DE102019124800A1 - Method for producing a thread, in particular an internal thread, with hard metal - Google Patents

Abstract

The method according to the invention increases the service life of taps made of hard metal.

Description

The invention relates to a method for producing a thread, in particular an internal thread.

A thread has a helical or helical thread turn with a constant thread pitch and can be produced as an internal thread or as an external thread. To create an internal thread, a core hole (or: a core hole) is usually first created in the workpiece, which can be a blind hole or a through hole, and then the thread is created in the inner wall of the core hole. The core hole with a thread created in it is also referred to as a threaded hole.

Both cutting and non-cutting methods and threading tools are known for thread generation or thread finishing. Machining thread generation is based on the removal of material from the workpiece material in the area of the thread. Non-cutting thread generation is based on reshaping the workpiece and generating the thread turn in the workpiece by pressure. The manual of thread technology and milling technology, publisher: EMUGE-FRANKEN, publisher: Publicis Corporate Publishing, year of publication: 2004 (ISBN 3-89578-232-7), in the following only as "EMUGE- Manual ”.

Taps (see EMUGE manual, chapter 8, pages 181 to 298) and thread milling cutters (see EMUGE manual, chapter 10 , Pages 325 to 372) and, only for external threads, the dies (see EMUGE manual, chapter 11, pages 373 to 404).

A tap is a thread cutting tool whose cutting edges or thread cutting teeth are arranged along an external thread below the thread pitch of the thread to be produced. When creating the thread, the tap is moved into a cylindrical core hole in a workpiece with a feed that is axial to the tool axis and while rotating around its tool axis at a rotational speed dependent on the axial feed rate according to the thread pitch, the tool axis of the tap being aligned coaxially with the center axis of the core hole and its cutting edges are permanently in engagement with the workpiece on the core hole wall (continuous cut), so that a continuous thread is created on the core hole wall. Typical geometries of a tap with the usual chamfer area are described in the EMUGE manual, chapter 8, pages 250 and 251 and 284 and 285. In the cutting direction, in cross section perpendicular to the helix, the thread cutting teeth have a cutting profile or active profile on the outer edge and then inwardly a rake face and on the back of the tooth adjoining the cutting direction, free surfaces or clearance angles, so that there is no contact and therefore no friction with the workpiece. A typical distribution of the individual thread action profiles of the thread cutting teeth ground at an angle in the chamfer area with the corresponding chip distribution is shown in the EMUGE manual, chapter 9, page 322.

The thread cutting process with a tap is explained together with a typical torque curve in the EMUGE manual, chapter 8, page 255. After the cutting process of the tap up to the engagement of all cutting teeth, the machine spindle is braked to a standstill. Now the return or the reversing movement is started and the tooth back of the thread cutting tooth preceding the thread cutting shears off the chip still in the hole on its free rear side and squeezes the chip root back between the free surface and the hole wall.

The non-cutting thread generating tools include the so-called thread formers (see EMUGE manual, chapter 9, pages 299 to 324) and, only for external threads, the thread rolling tools (see EMUGE manual, chapter 11, pages 373 to 404).

Thread forming tools are threading tools with an approximately spiral or helical circumferential thread profile, along which several press studs (also referred to as shaped teeth, shaped teeth or shaped wedges) are arranged, which are offset by further outwardly protruding and generally rounded polygonal corner areas of an approximately polygonal cross-section of the Thread formers are formed. When creating the thread, the thread former is moved into a cylindrical core hole in a workpiece, similar to the tap, with an advance that is axial to the tool axis and while rotating around its tool axis, the tool axis of the tap being aligned coaxially to the central axis of the core hole. The speed of rotation and the axial feed speed are matched to one another according to the thread pitch. The press studs of the thread former are permanently in engagement with the workpiece on the core hole wall and press the thread turn into the core hole wall by plastic deformation, so that a continuous thread turn is created on the core hole wall. Typical geometries of a Thread formers with the usual starting area are described in the EMUGE manual, chapter 9, pages 308 and 309. A typical distribution of the individual thread action profiles of the thread rolling teeth rising in the threading area is shown in the EMUGE manual, chapter 9, page 322. The thread forming process with a thread former is explained together with a typical torque curve in the EMUGE manual, chapter 9, page 310.

Taps and taps work with an exclusively axial feed or working movement with a rotational movement around their own tool axis that is synchronized according to the thread pitch. The direction of rotation of the tap and the thread former when creating the thread corresponds to the direction of winding of the thread to be created. When the thread turn is generated or at the end of the generation of the thread turn, the tool is braked and brought to a standstill at a reversal point. The deceleration before reaching the reversing or reversal point is normally brought about by reducing the axial feed rate and speed to a value of 0, which is synchronized according to the constant thread pitch. To retrieve the tool from the workpiece, a backward or reversing movement is initiated, in which the axial feed direction and the direction of rotation are exactly opposite to the working movement and the axial feed movement and rotational movement are again synchronized according to the thread pitch so as not to damage the thread.

In practice, taps and taps are used which are produced monolithically, generally by machining, in particular grinding, from a blank.

In addition, it is also known to form the working areas of taps with the thread teeth or thread cutting or the working areas of thread grooves with the form teeth or press studs on separate thread generating elements and to attach these thread generating elements to a support body or holder. The carrier body here has the coupling shaft for coupling to the machine drive, usually via a tool holder.

The materials used for the taps or taps are generally high-speed steel such as high-speed steel (HSS steel) or cobalt-alloyed high-speed steel (HSS-E steel) or hard metal such as a hard metal alloy, in particular P steel or K steel or cermet, or cemented carbide, in particular tungsten carbide , optionally alloyed or mixed with metals or other metal carbides, or titanium nitride or titanium carbide or titanium carbonitride or aluminum oxide, or cutting ceramics, in particular polycrystalline boron nitride (PCB), or polycrystalline diamond (PCD).

The use of the harder materials, which are advantageous for machining workpieces made of harder materials, in particular hard metal, for taps or taps is in practice severely limited by the brittleness of these materials, especially when they are used very frequently in thread production in steels, especially tough steels . In practice, in particular, when machining workpieces made of steel, the problem arises that the remaining material protrusions, in particular the chip roots and disruptive chips, especially long curly chips, when tapping or grooving claws or form bead in thread cutting now break when running backwards after the reversal point brittle material can lead. This is why taps and taps made of carbide have not been able to establish themselves on the market and the predominant material is HSS.

According to the EP 2 229 257 B1 Carbide taps have advantages over taps made of high-speed steel due to the greater material hardness and higher compressive strength and greater temperature stability, for example theoretically a higher rotation speed and longer service life. Carbide taps are ideal for drilling threads in gray cast iron (GG) or aluminum. However, taps made of hard metal in steels have a comparatively short service life, which is usually shorter than that of comparable HSS or HSS-E taps. The lower service life of carbide taps is probably due to the fact that the thread cutting breaks prematurely or is partially torn off or worn off due to the higher brittleness and lower elasticity as well as the lower breaking strength and toughness of carbide compared to high-speed steel. The EP 2 229 257 B1 now proposes to create a targeted and defined rounding of at least part of the cutting edges of thread cutting teeth, at least in the area of the outer cutting or tip cutting, of a tap and thus to increase the service life, even if the thread cutting edges are made of hard metal and threads are cut in steel. The curvature of the cutting edge rounding and / or the removal depth of the rounded cutting edge is compared to the ideal wedge shape depending on at least the two parameters number of thread cutting teeth in the starting area and thread pitch and preferably also on the third parameter increase in the maximum radial distance of the outer cutting edges or cutting edges Thread cutting teeth selected over the lead area.

From the DE 10 2016 008 478 A1 a combination tool is known with which a threaded hole is produced in a workpiece in one work step solely by an axial work movement. With this combination tool, which is referred to as a bullet tapping tool, the core hole drilling and the internal thread cutting are carried out in one tool stroke. In order to reduce the tool load, DE 10 2016 008 478 A1 Suggested that after the tapping stroke the reversing stroke does not follow immediately, but rather a groove forming step or groove forming stroke takes place beforehand, in which a circumferential groove adjoining the internal thread is formed without a thread pitch, in which the thread profile of the tapping tool rotates without stress can. The tapping tool is moved beyond the target thread depth for the tapping stroke until a target drilling depth is reached, with a groove form feed and a groove form speed that are not synchronized with one another and different from the tapping feed and for tapping speed. The circumferential groove is generated during the groove form stroke with the help of the main cutting edge and the thread cutting tooth (or general thread tooth) of the thread profile on the tapping tool. When the target drilling depth is reached, the groove form feed is reduced to 0. At the same time, the groove form speed is reduced to 0 in order to enable the reversal of the direction of rotation required for the reversing stroke. The DE 10 2016 008 478 A1 does not provide any information on the materials for the tool.

The invention is based on the object of specifying a new method in each case for producing a thread, in particular an internal thread in a core hole or an external thread, in a workpiece. In particular, the method is intended to improve the service life of taps or thread formers, which are made of a brittle material such as hard metal or cutting ceramic, at least in the area of their thread teeth, even when machining different steels.

Embodiments and objects according to the invention which are suitable for solving this object are specified in particular in the patent claims, which are directed to a method for producing a thread, in particular an internal thread.

Further refinements and developments according to the invention emerge from the respective dependent claims.

The claimable combinations of features and subjects according to the invention are not restricted to the selected version and the selected back-references of the patent claims. Rather, each feature of a claim category, for example a method, can also be claimed in another claim category, for example a tool. Furthermore, each feature in the patent claims, regardless of their back-references, can be claimed in any combination with one or more other feature (s) in the patent claims. In addition, each feature described or disclosed in the description or drawing can be used individually, independently or separately from the context in which it stands, alone or in any combination with one or more other features that are stated in the claims or is or are described or disclosed in the specification or drawing may be claimed.

• a) ein Werkzeug zum Erzeugen eines Gewindes verwendet,
• a1) wobei das Werkzeug um eine durch das Werkzeug verlaufende Werkzeugachse drehbar und axial zur Werkzeugachse bewegbar ist,
• a2) wobei das Werkzeug wenigstens einen Gewindeerzeugungsbereich umfasst, der mit einer vorgegebenen Gewindesteigung und einem vorgegebenen Windungssinn des zu erzeugenden Gewindes um eine durch das Werkzeug verlaufende Werkzeugachse verläuft und ein Wirkprofil aufweist, das dem Gewindeprofil des zu erzeugenden Gewindes entspricht,
• a3) wobei jeder Gewindeerzeugungsbereich einen oder mehrere Gewindezähne aufweist,
• b) das Werkzeug in einer Arbeitsbewegung während einer ersten Arbeitsphase in das vorgefertigte, d.h. bereits vorhandene, Kernloch im Werkstück bewegt,
• b1) wobei die Arbeitsbewegung eine Drehbewegung mit einem vorgegebenen Drehsinn um die Werkzeugachse des Werkzeugs und eine gemäß der Gewindesteigung des Gewindeerzeugungsbereichs mit der Drehbewegung synchronisierte axiale Vorschubbewegung des Werkzeugs in einer axialen Vorwärtsrichtung axial zur Werkzeugachse umfasst, derart, dass einer vollen Umdrehung des Werkzeugs um die Werkzeugachse ein axialer Vorschub des Werkzeugs um die vorgegebene Gewindesteigung entspricht,
• b2) wobei der Gewindeerzeugungsbereich während der ersten Arbeitsphase in der Arbeitsbewegung einen unter der vorgegebenen Gewindesteigung verlaufenden Gewindegang in der Wandung des Kernloches erzeugt,
• c) wobei das Werkzeug in einer Abbremsbewegung während einer zweiten Arbeitsphase im Anschluss an die erste Arbeitsphase weiter in das Werkstück bis zu einem Umkehrpunkt bewegt wird,
• c1) wobei der axiale Vorschub des Werkzeugs bezogen auf eine volle Umdrehung zumindest während eines Teils der Abbremsbewegung, vorzugsweise während der gesamten Abbremsbewegung, betragsmäßig kleiner als die Gewindesteigung ist und beim Umkehrpunkt Null ist und
• c2) wobei der Gewindeerzeugungsbereich, insbesondere der Gewindezahn oder die Gewindezähne, des Werkzeugs während der Abbremsbewegung wenigstens eine, insbesondere geschlossene oder ringförmige, Umfangsnut in der Wandung des Kernloches im Werkstück erzeugt.

The method according to claim 1 is provided for producing a thread with a predetermined thread pitch in a prefabricated core hole in a workpiece. The procedure will

• a) a tool is used to create a thread,
• a1) wherein the tool is rotatable about a tool axis running through the tool and can be moved axially to the tool axis,
• a2) wherein the tool comprises at least one thread generation area which runs with a predetermined thread pitch and a predetermined direction of winding of the thread to be generated around a tool axis running through the tool and has an active profile which corresponds to the thread profile of the thread to be generated,
• a3) each thread generation area having one or more thread teeth,
• b) the tool is moved into the prefabricated, ie already existing, core hole in the workpiece in one working movement during a first working phase,
• b1) wherein the working movement comprises a rotary movement with a predetermined direction of rotation around the tool axis of the tool and an axial feed movement of the tool in an axially forward direction axially to the tool axis, which is synchronized with the rotary movement according to the thread pitch of the thread generating area, such that one full revolution of the tool around the Tool axis corresponds to an axial feed of the tool by the specified thread pitch,
• b2) wherein the thread generation area during the first work phase in the Working movement creates a thread in the wall of the core hole that runs below the specified thread pitch,
• c) wherein the tool is moved further into the workpiece up to a reversal point in a braking movement during a second work phase following the first work phase,
• c1) wherein the axial advance of the tool, based on a full revolution, is at least during part of the braking movement, preferably during the entire braking movement, smaller in amount than the thread pitch and is zero at the reversal point and
• c2) wherein the thread generation area, in particular the thread tooth or the thread teeth, of the tool generates at least one, in particular closed or annular, circumferential groove in the wall of the core hole in the workpiece during the braking movement.

In order to increase the service life of taps, the invention takes a different approach than the one mentioned above EP 2 229 257 B1 . While in EP 2 229 257 B1 an improvement to the tool, namely the cutting edge rounding, is proposed, which can of course also be provided in the tool of the invention, the invention is based on the consideration of improving the process, i.e. the movement sequence of the tool and the programming of the machine control. According to the invention, it is proposed that for the special case of the combined drilling and tapping tool, which works in the solid material and generates core hole and thread at the same time, according to the aforementioned DE 10 2016 008 478 A1 provided groove forming step between the thread generation step and the reversal point now in the conventional generation of threads in already prefabricated core holes with a tap that does not have or does not have a drilling part or drilling area, and for this purpose also to be further improved.

Furthermore, this advantageous combination according to the invention is extended not only for taps but also for taps or for combined tapping and thread forming tools, i.e. generally axially operating threading tools with thread generating areas formed helically according to the thread pitch when generating threads in a prefabricated core hole.

In a multi-part embodiment, the tool comprises a carrier body through which the tool axis runs, and at least one thread generating element, in particular produced separately from the carrier body, which is fastened to the carrier body, in particular is fastened interchangeably or detachably, each thread generating element having at least one thread generating area.

In one embodiment, the or each thread generating area is arranged on a front end area of the tool and / or the or each thread generating element is attached to a front end area of the support body, preferably on an end face of the support body.

In one embodiment, the thread generating element is designed as an end-face threaded head with the complete thread generating area or all thread teeth, the tool axis running centrally through the carrier body and the thread generating element, and the thread generating element preferably at the front by means of a central fastening screw guided axially through a central opening in the thread generating element The end face of the carrier body is attached,

In a further embodiment, several thread generating elements are fastened separately to the carrier body and distributed around the tool axis in the circumferential direction and are arranged at a distance from one another.

In one embodiment with reusable thread generating elements, the or each thread generating element has a working active thread tooth or a working active thread cutting edge and additionally at least one, in particular one, two or three, further non-active thread tooth or thread cutting edge, which or which by loosening the releasable fastening, turning and / or turning of the thread generating element and reattaching on the carrier body to one or an active working thread tooth or thread cutting edge. For example, can
the or each thread generating element in an approximately rectangular or triangular symmetrical and plate-shaped basic shape have four or three thread cutting edges at the four or three corners with respective upstream rake faces.

In a preferred embodiment, the or each thread generating element is inserted in an associated receptacle of the carrier body, in particular on its end face, and in particular is detachably and exchangeably fastened to the carrier body by means of a fastening screw guided through a central opening in the thread generating element. The receptacles are preferably adapted to the thickness of the thread generating elements, see above that the front surfaces of the thread generating elements terminate essentially flush with the end surface of the carrier body.

The carrier body can now be manufactured very efficiently and at least in the area of the thread generating element have a cylindrical shape with respect to the tool axis, in particular also a cylindrical neck and / or at least partially made of steel, in particular high-strength steel.

In another embodiment, the tool has thread generating regions formed monolithically on a base body through which the tool axis extends.

In one embodiment, in the base body, which in particular has a cylindrical basic shape, several, in particular five, successive thread teeth are separated from one another by several, for example five, preferably axially to the tool axis running separating grooves, which are arranged along the circumference around the tool axis and in Winding sense thread cutting and have free surfaces behind, wherein in particular axially behind the thread generating area formed from the thread teeth, a cylindrical outer surface of the base body is formed.

Thread depth is lost due to the creation of circumferential grooves. It is therefore advantageous in the tool and process according to the invention if the or each thread generation area in the axial direction to the tool axis has an axial extension from a range between 0.5 P and 1.5 P of the thread pitch P or in which the axial distance to the tool axis between the first thread tooth opposite to the winding direction and the last thread tooth of the thread generating area from a range between 0.5 P and 1.5 P of the thread pitch P is chosen, so as short as possible, which is a difference to a conventional tap or thread forming machine.

To compensate for the reduced guidance of the tool as a result, in a preferred embodiment a cylindrical guide area is formed in front of the thread generating area for guiding the tool on the core hole wall in the core hole.

In one embodiment, a start-up area is provided or the thread profile of the thread turn is successively cut and / or formed from the individual thread teeth to the complete thread profile and / or the thread action profiles of the individual thread teeth are divided and, when combined, result in the complete thread profile.

In a particularly advantageous embodiment of the invention, the material for the thread teeth and / or the or each thread generation area and / or the thread generation elements and / or the carrier body and / or the base body and / or the entire tool, hard metal such as a hard metal alloy, in particular P -Steel or K steel or cermet, or cemented carbide, in particular tungsten carbide, optionally alloyed or mixed with metals or other metal carbides, or titanium nitride or titanium carbide or titanium carbonitride or aluminum oxide, or cutting ceramics, especially polycrystalline boron nitride (PKB), or polycrystalline diamond (PKD) used.

• d) während der Arbeitsbewegung die (tatsächliche) Drehzahl der Drehbewegung des Werkzeugs in ihrem zeitlichen Verlauf ein erstes Plateau, bei dem die Drehzahl konstant auf einer vorgegebenen (oder: programmierten oder im Steuerprogramm eingegebenen) maximalen Drehzahl bleibt, durchläuft und
• e) während der Abbremsbewegung die (tatsächliche Drehzahl) der Drehbewegung des Werkzeugs in ihrem zeitlichen Verlauf ein zweites Plateau, bei dem die Drehzahl konstant auf derselben vorgegebenen maximalen Drehzahl bleibt, durchläuft,
• f) wobei die vorgegebene maximale Drehzahl der Drehbewegung des Werkzeugs mindestens so groß gewählt ist, dass eine Bahngeschwindigkeit am Gewindeerzeugungsbereich von mindestens 57 m/min, insbesondere von mindestens 85 m/min, erreicht wird, was bei einem Gewindedurchmesser von 6 mm einer maximalen Drehzahl von mindestens 3000 U/min, insbesondere mindestens 4.500 U/min, entspricht.

In one embodiment according to the invention it is now provided that

• d) during the working movement, the (actual) speed of the rotary movement of the tool in its temporal course runs through a first plateau at which the speed remains constant at a predetermined (or: programmed or entered in the control program) maximum speed, and
• e) during the braking movement, the (actual speed) of the rotary movement of the tool runs through a second plateau over time, at which the speed remains constant at the same predetermined maximum speed,
• f) the specified maximum speed of the rotary movement of the tool is selected to be at least large enough that a path speed of at least 57 m / min, in particular of at least 85 m / min, is achieved at the thread generation area, which is a maximum speed with a thread diameter of 6 mm of at least 3000 rpm, in particular at least 4,500 rpm.

• d) das Werkzeug in der Arbeitsbewegung und in der Abbremsbewegung von einem Maschinenantrieb angetrieben wird und zwischen den Maschinenantrieb und das Werkzeug eine Übersetzungseinheit für die Drehbewegung, insbesondere eine Übersetzungsgetriebeeinheit, mit einem vorgegebenen oder vorgebbaren Übersetzungsverhältnis geschaltet (oder: gekoppelt) ist,
• e) wobei das Übersetzungsverhältnis dem Quotienten aus der Drehzahl des Maschinenantriebs und der Drehzahl des Werkzeugs entspricht und maximal 1:3 beträgt, so dass das Werkzeug mindestens dreimal so schnell dreht wie der Maschinenantrieb,
• f) wobei in der Programmierung des Maschinenantriebs eine maximale Drehzahl der Drehbewegung des Maschinenantriebs programmiert wird, die dem Produkt aus dem Übersetzungsverhältnis und der vorgegebenen maximalen Drehzahl der Drehbewegung am Werkzeug entspricht.

In one embodiment according to the invention, which is preferably combined with the aforementioned embodiments, it is provided that

• d) the tool is driven by a machine drive in the working movement and in the braking movement and a transmission unit for the rotary movement, in particular a transmission gear unit, is connected (or coupled) with a predetermined or predefinable transmission ratio between the machine drive and the tool,
• e) where the transmission ratio corresponds to the quotient of the speed of the machine drive and the speed of the tool and is a maximum of 1: 3, so that the tool rotates at least three times as fast as the machine drive,
• f) a maximum speed of the rotary movement of the machine drive is programmed in the programming of the machine drive, which corresponds to the product of the transmission ratio and the specified maximum speed of the rotary movement on the tool.

In one embodiment, there is an intermediate time interval between the time interval of the first plateau of the speed and the time interval of the second plateau of the speed, in which the speed drops below the maximum speed.

In one embodiment, the ratio of the interval length of the intermediate time interval to the interval length of the time interval of the second plateau is in a range from 0.5 to 2.4.

In one embodiment, the interval length of the second plateau is selected in a range from 0.01 s to 0.25 s, in particular 0.02 s to 0.13 s, and / or the interval length of the intermediate time interval is between 0.05 in one embodiment s and 0.15 s, in particular between 0.06 and 0.10 s.

In one embodiment, the maximum speed is already reached at the beginning of the first work phase or the work movement or at the point where the tool enters the workpiece.

In one embodiment, the maximum web speed achieved at the thread generation area is selected in a range from 57 m / min to 189 m / min, in particular from 85 m / min to 132 m / min.

In one embodiment, the transmission ratio is generally selected between 1: 3 and 1:10, in particular between 1: 4 and 1: 8, preferably between 1: 4 and 1: 5.

The braking movement preferably comprises a rotary movement with a constant direction of rotation as in the working movement.

As a rule, the braking process or the second work phase begins with an axial feed that corresponds to the thread pitch of the first work phase. The braking process is to be understood as braking from the initial thread pitch to zero at the end or at a reversal point and does not have to include a reduction in the axial feed rate over the entire angle of rotation interval depending on the angle of rotation (braking acceleration), in particular to values below the thread pitch. Rather, rotation angle intervals are also possible in which the axial advance is zero or even temporarily negative in relation to the rotation angle, that is to say reverses its direction.

In a preferred embodiment, the axial advance movement is controlled during the braking movement depending on the angle of rotation of the rotational movement of the tool according to a previously stored unique relationship, in particular a function or a sequence of functions, between the axial advance of the tool and the angle of rotation.

A function that defines the relationship between the axial feed (or: the axial penetration depth) and the angle of rotation can have a continuous definition range and value range or also a discrete definition range and value range with discrete, previously stored or previously determined value pairs or value tables.

In one embodiment, the rotational speed of the rotational movement at the reversal point is also zero. and / or the total or total axial feed of the tool during the braking movement is selected or set between 0.1 times and 2 times the thread pitch.

In a preferred embodiment, different relationships, in particular functions, between the axial advance of the tool and the angle of rotation are selected or set during the braking movement in several successive braking steps.

In a particularly advantageous embodiment, a linear function of the angle of rotation is selected during several, in particular all, braking steps for the axial penetration depth or the axial feed and / or the (programmed) slope, ie the derivation of the axial penetration depth or the axial feed according to the Angle of rotation, constant in each of these braking steps and decreases in amount from one braking step to a subsequent braking step.

This embodiment can be implemented in a particularly simple manner by using an NC control for a thread process, for example a G33 path condition, with the thread pitch of the thread for the work movement and also one, preferably the same, NC control for a thread process in the several braking steps , for example a G33 path condition, with the respective constant pitch is used as the thread pitch parameter.

In one embodiment, during several, in particular all, braking steps, the axial penetration depth or the axial advance is an, in particular cubic, spline function of the angle of rotation.

In one embodiment, the different functions of successive braking steps are continuously and, in the case of differentiable functions, preferably continuously differentiable.

In one embodiment, in particular during an equalization step, the axial advance during the braking movement is zero in a rotation angle sub-interval and / or takes place in a rotation angle sub-interval in the reverse direction opposite to the forward direction of the working movement.

In one embodiment, after reaching the reversal point, a reversing movement of the tool is initiated, with which the tool is moved out of the workpiece, the reversing movement initially being a first reversing phase, with which the thread generating area of the tool is guided back into the thread of the generated thread, and in the Connection includes a second reversing phase, during which the thread generation area is guided out of the workpiece through the thread turn.

The reversing movement is preferably carried out with a course of movement that is symmetrical to the working movement and the braking movement, with the opposite direction of rotation and the opposite feed.

In an advantageous embodiment, the reversing movement is controlled in the first reversing phase with the same absolute value, only inverted in the direction of rotation and feed direction, previously stored unique relationship, in particular a function or a sequence of functions, between the axial advance of the tool and the angle of rotation, as in the Braking movement during the second work phase, possibly omitting or shortening the equalization step, if available.

• 1 ein Gewindeerzeugungswerkzeug bei der Erzeugung eines Gewindes,
• 2 bis 10 aufeinanderfolgende Schritte eines Verfahrens oder Zyklus zur Erzeugung eines Gewindes mit einem Gewindeerzeugungswerkzeug, insbesondere gemäß 1,
• 11 ein mit dem Verfahren und Werkzeug nach den 1 bis 10 hergestelltes Gewinde,
• 12 die Steuerung eines Gewindeerzeugungszyklus anhand eines Graphen der axialen Eindringtiefe als Funktion des Drehwinkels,
• 13 der Endabschnitt des in 12 dargestellten Graphen in der Vorwärtsbewegung als Abbremsvorgang,
• 14 der Endabschnitt des in 12 dargestellten Graphen in der Rückwärtsbewegung als Beschleunigungsvorgang,
• 15 ein Diagramm der Eindringtiefe und der Drehzahl als Funktionen der Zeit mit einer Übersetzungseinheit zwischen Antriebseinheit und Werkzeug gemäß der Erfindung und
• 16 ein Diagramm der Eindringtiefe und der Drehzahl als Funktionen der Zeit ohne eine Übersetzungseinheit zwischen Antriebseinheit und Werkzeug,
• 17 ein Gewindeerzeugungswerkzeug mit drei Gewindezähnen an einem stirnseitigen Gewindeerzeugungselement an einem Trägerkörper in einer perspektivischen Darstellung,
• 18 ein Gewindeerzeugungswerkzeug mit sechs stirnseitigen Gewindeerzeugungselementen an einem Trägerkörper in einer Stirnansicht,
• 19 das Gewindeerzeugungswerkzeug gemäß 18 in einer perspektivischen Darstellung,
• 20 das Gewindeerzeugungswerkzeug gemäß 18 und 19 in einer Seitenansicht,
• 21 das Gewindeerzeugungswerkzeug gemäß 18 bis 20 in einer gegenüber 20 gedrehten Seitenansicht,
• 22 ein Gewindeerzeugungswerkzeug mit acht Gewindezähnen an einem stirnseitigen Gewindeerzeugungselement an einem Trägerkörper in einer perspektivischen Darstellung,
• 23 bis 26 ein monolithisches Gewindeerzeugungswerkzeug gemäß der Erfindung und
• 27 bis 30 Ausführungsbeispiele für Aufteilungen der Gewindewirkprofile der Gewindezähne jeweils in einem Querschnitt,

jeweils schematisch dargestellt sind. Einander entsprechende Teile und Größen sind in den 1 bis 30 mit denselben Bezugszeichen versehen.The invention is explained further below with the aid of exemplary embodiments. Reference is also made to the drawing, in which

• 1 a thread creation tool when creating a thread,
• 2 to 10 successive steps of a method or cycle for generating a thread with a thread generating tool, in particular according to FIG 1 ,
• 11 one with the method and tool according to the 1 to 10 manufactured thread,
• 12th the control of a thread generation cycle using a graph of the axial penetration depth as a function of the angle of rotation,
• 13th the end section of the in 12th graph shown in the forward movement as a braking process,
• 14th the end section of the in 12th graph shown in the backward movement as an acceleration process,
• 15th a diagram of the penetration depth and the speed as a function of time with a translation unit between the drive unit and tool according to the invention and
• 16 a diagram of the penetration depth and the speed as a function of time without a transmission unit between the drive unit and the tool,
• 17th a thread generating tool with three thread teeth on an end-face thread generating element on a carrier body in a perspective view,
• 18th a thread generating tool with six end-face thread generating elements on a carrier body in an end view,
• 19th the threading tool according to 18th in a perspective view,
• 20th the threading tool according to 18th and 19th in a side view,
• 21 the threading tool according to 18th to 20th in an opposite 20th rotated side view,
• 22nd a thread generating tool with eight thread teeth on an end thread generating element on a carrier body in a perspective view,
• 23 to 26th a monolithic threading tool according to the invention and
• 27 to 30th Exemplary embodiments for the division of the thread action profiles of the thread teeth each in a cross section,

are each shown schematically. Corresponding parts and sizes are in the 1 to 30th provided with the same reference numerals.

First exemplary embodiments of the tool and method according to the invention are described below with reference to FIG 1 to 11 explained.

This in 1 shown tool 2 is used to create a thread 5 in one workpiece 6th used. For this purpose, the tool is inserted into the core hole in a working movement or a working stroke or a thread generating movement, which is composed of a rotary movement around the tool axis on the one hand and an axial feed movement along the tool axis 35 in the workpiece 6th emotional. The diameter of the core hole 35 is denoted by d.

The 11 shows an embodiment of a threaded hole 36 with one thread 50 and a thread profile 55 of the thread 5 that with a method or a tool according to the invention, for example according to 1 or 2 to 10 , can be produced.

berechenbar. Typische Werte für den Gewindesteigungswinkel δ liegen beispielsweise zwischen 1° und 5°.The thread pitch angle δ of the thread 50 with the thread pitch P and the diameter D. is with respect to a transverse plane E, which is perpendicular to the tool axis A. is directed, measured and is from the following relationship $$\text{P}=\mathrm{\pi }\cdot \text{D tan}\cdot \mathrm{\delta }$$

predictable. Typical values for the thread lead angle δ lie, for example, between 1 ° and 5 °.

The tool 2 is the one hand to one through the tool 2 running tool axis A. rotatable or rotationally movable and on the other hand along or axially to the tool axis A. axially or translationally movable. These two movements are coordinated or synchronized with one another, preferably by a control unit, in particular a machine controller, while the tool is being used 2 on a surface 60 of the workpiece 6th and down to a hole depth LT in the core hole 35 of the workpiece 6th penetrates. The tool axis A. remains during the creation of the thread 5 relative to the workpiece 6th stationary or constant position. The thread center axis M. of the thread 5 is coaxial with the tool axis during the process A. or coincides with this.

The tool 2 is preferably by means of a coupling area on one axially to the tool axis A. running or trained tool shank 21 by means of a rotary drive, not shown, in particular a machine tool and / or drive or machine tool spindle, rotationally or in a rotary movement about its tool axis A. can be driven as an axis of rotation in a forward direction of rotation VD and in an opposite reverse direction of rotation RD. Further is the tool 2 axially in an axial forward movement VB or an axial backward movement RB axially to the tool axis A. movable, in particular by means of an axial drive, which in turn can be provided in the machine tool and / or drive or machine tool spindle.

On one of the coupling area of the tool shank 21 remote free end of the tool 2 is a carrier body 20th provided on which a thread generation area 4th is monolithic or in one piece or via one or more separate thread generating elements (in 1 not shown) is arranged or attached.

The thread creation area 4th is that along a helix (or: helix, thread), the pitch of which is the thread pitch P and their direction of winding the direction of winding of the internal thread or thread to be generated 50 corresponds to, runs or is formed. In this sense, the helical line is to be understood technically and not as a purely mathematical one-dimensional line, but also has a certain extent transversely to the mathematical line, that of the corresponding dimension of the thread generation area 4th corresponds to. Mathematically, one would otherwise have to speak of a family of helical lines running parallel to each other or possibly of a screw band or helix band. The winding direction of the thread creation area 4th as a right-hand thread or left-hand thread corresponds to the superposition of axial forward movement VB and forward rotation VD.

The thread creation area 4th comprises one or more, ie a number n greater than or equal to 1, thread teeth which are designed to be cutting and / or shaping. Preferably n = 2.

Each thread tooth is formed or aligned or arranged to run along the helical line. Each thread tooth has a thread tooth profile as an effective profile, which generally results or represents the outermost dimension or outer profile of the thread tooth in a projection along the helical line and is mapped into the workpiece during the thread generating movement, be it by cutting or by shaping or pressing.

If several (n> 1) thread teeth from the thread generation area 4th are included, these thread teeth are arranged offset to one another at least approximately along the helical line (or in the axial direction). Such an arrangement along the helical line also includes embodiments in which the thread teeth are slightly offset laterally to an ideal line, for example around thread knitting profiles with different processing on the thread flanks or a different division or superposition of the Realize thread action profiles on or to the overall thread profile. With regard to this arrangement of the thread teeth, it is only important that their arrangement during the working movement relates to a thread turn in the workpiece with the same thread pitch P maps.

In the in 1 to 10 The illustrated embodiments are two thread teeth 41 and 42 are provided, for example by half or generally 1 / n of the thread pitch P are axially offset from one another, that is, they are offset in the angular direction corresponding to half a revolution or by 180 °. The outside diameter of the thread creation area 4th and the thread 50 and thus of the thread 5 is denoted by D. The thread profile of the internal thread, i.e. the cross section through the thread turn 50 , is generated by the active thread profile composed or superimposed from the individual active profiles of the thread teeth, eg 41 and 42, when the workpiece is completely passed through.

The one in axial projection onto the tool axis A. The measured thread profile width of the thread active profile is denoted by c and corresponds to the maximum distance between the thread profile flanks. The one in axial projection onto the tool axis A. measured axial distance between two successive thread profiles of the thread turn 50 is the thread gap b . The sum of the thread gap b and the thread width c corresponds to the thread pitch here P .

The thread teeth 41 and 42 are in these embodiments by separating grooves 25th which in particular form chip flutes or also coolant and / or lubricant grooves in the carrier body 20th and / or the thread generating element (s) separated from one another. The separating grooves 25th settle through the threading area 4th through, in particular, into the shaft area and preferably run twisted at a constant or variable twist angle, which is typically in an interval of 0 ° to 50 °, in particular 20 ° to 35 °.

• Während einer ersten Arbeitsphase oder Gewindeerzeugungsphase wird mit dem Werkzeug 2 der Gewindegang 50 in der Kernlochwandung des Kernloches 35 mittels des Gewindeerzeugungsbereichs 4 erzeugt. In dieser ersten Arbeitsphase wird die axiale Vorschubgeschwindigkeit v entlang der Werkzeugachse A auf die Drehgeschwindigkeit für die Drehbewegung um die Werkzeugachse A so abgestimmt und synchronisiert, dass bei einer vollen Umdrehung der axiale Vorschub der Gewindesteigung P entspricht. Die axiale Eindringtiefe (oder: der axiale Vorschub) T in Richtung der Werkzeugachse A gemessen von der Werkstückoberfläche 60 in dieser ersten Arbeitsphase entspricht der Gewindetiefe T_G . Die Variable T entspricht in einer üblichen NC-Maschinensteuerung der z-Achse.

In an advantageous embodiment, the tool 2 or another tool according to the invention, the following procedure is carried out:

• During an initial work phase or thread creation phase, the tool is used 2 the thread 50 in the core hole wall of the core hole 35 by means of the thread generation area 4th generated. In this first work phase, the axial feed rate v is along the tool axis A. on the rotational speed for the rotary movement around the tool axis A. coordinated and synchronized in such a way that the axial advance of the thread pitch is achieved with one full revolution P corresponds to. The axial penetration depth (or: the axial feed) T in the direction of the tool axis A. measured from the workpiece surface 60 in this first working phase corresponds to the thread depth T _G . The variable T corresponds to the z-axis in a normal NC machine control.

In a second work phase immediately following the first work phase, the tool is now in a braking process (or: in a braking movement) 2 braked in an angle of rotation interval in such a way that the axial feed V at an angle of rotation of 360 °, ie with a full revolution, of the tool 2 smaller than the thread pitch P and decreases to zero. As a rule, the braking process or the second work phase begins with an axial feed rate based on an angle of rotation of 360 °, that of the thread pitch P corresponds to the first work phase, i.e. V = P, and then reduces the axial feed per 360 ° angle of rotation to values below the thread pitch P , i.e. V <P. The braking process is to be understood as braking from the initial thread pitch V = P down to zero at the end or at a reversal point, i.e. V = 0, and does not have to reduce the axial feed rate V over the entire angle of rotation interval depending on the Include angle of rotation (deceleration). Rather, rotation angle intervals are also possible in which the axial advance is zero or even temporarily negative in relation to the rotation angle, that is to say reverses its direction.

In a preferred embodiment, this braking process takes place in defined sub-steps, as will be explained in more detail below.

This braking movement in the second work phase leads to the thread generation area 4th now - in an actually atypical or non-functional manner - at least one circumferential groove or circumferential groove or circumferential groove (or: an undercut) in the core hole wall of the core hole 35 generated. The process in the second work phase can therefore not only be referred to as a braking process but also as a circumferential groove generation or circumferential groove generation or undercut movement, and in the case of a purely cutting tool, it can also be referred to as a free-cutting movement.

In 1 are the thread generating teeth 41 and 42 with the same outer radius D. / 2 and preferably the same active thread profile that is already the end profile of the thread turn 50 corresponds, shown. The thread generating teeth 41 and 42 of the tool according to FIG 1 create a circumferential groove in the second work phase 51 with the continuous outer diameter D. and the axial length a , which results from the total axial advance of the braking movement in the second work phase up to the reversal point.

In 11 are, however, two circumferential grooves 51 and 52 shown, the first circumferential groove 51 one between the core hole diameter d and the outer thread diameter D. lying outside diameter d 'and the second circumferential groove 52 has an outside diameter equal to the thread outside diameter D. corresponds to.

Such circumferential grooves 51 and 52 can, for example, with two thread generating teeth offset by P / 2 during the second work phase 41 and 42 such as in 1 shown, which can be modified as follows: The first thread generating tooth 41 in 1 only have an outer radius d '/ 2 and thus be a chamfer or chamfer tooth that forms the thread 50 not generated up to the full profile depth or up to the final thread root, while the second thread generating tooth 42 already has the full outer diameter D. has, i.e. generates the full thread profile depth (full tooth).

In this exemplary embodiment, the circumferential groove is thus composed of two partial grooves, namely the first circumferential groove with a smaller diameter 51 that from the first threading tooth 41 and the one with the full diameter D. formed second circumferential groove 52 generated by the second thread generating tooth 42.

These explanations are only exemplary. In the case of a different number or distribution of thread generating teeth, not shown, correspondingly different circumferential grooves result.

If you have the circumferential groove (s), for example the circumferential grooves 51 and 52 in 11 or the circumferential groove 51 in 1 , are to be generated continuously or uninterrupted in the axial direction, the axial feed V is reduced at a full revolution or 360 ° in particular by at least b / n compared to P, by the thread gap b to close or no longer to be generated, where n is the number of thread generating teeth in the thread generating area 4th is.

The undercut movement or braking movement, for example by suitable selection of the movement parameters or also by additional axial equalizing movements, can also be carried out in such a way that the outer width on the thread profile, in particular the flanks, are no longer visible in the circumferential groove or disappear and / or the circumferential groove is only visible has a cylindrical shape. In this way, the screwability of the workpiece thread produced could be improved or made possible.

In the in 1 to 11 illustrated embodiments is n = 2 with the two thread generating teeth 41 and 42 or circumferential grooves 51 and 52 so that the axial feed V during the braking process is preferably set smaller than P − b / 2. The thread action profile of the thread generating teeth, here 41 and 42, then no longer generates a thread in the superposition during the movement, but at least one continuous circumferential groove that has the same outer diameter as that of the associated thread generating tooth on its respective path during the braking movement in the second work phase corresponds to.

The total depth or hole depth or total axial dimension of the threaded hole 5 after the second work phase is with T _L and corresponds essentially to the sum of the thread depth T _G as axial feed in the first working phase and the axial groove length a as an axial advance in the second work phase and the axial depth of the remaining bore sub-area 56.

When the total depth or hole depth T _L of the threaded hole 5 is reached, the tool comes 2 comes to a standstill and reaches a turning point UP .

It will now be at the turning point UP an immediate reversing or backward movement RB initiated with the tool 2 initially in a first reversing phase through the circumferential groove (s) 51 , 52 up to the thread 50 is moved back and then in a second reversing phase through the thread 5 or the thread 50 outwards from the threaded hole 36 and then the workpiece 6th is moved out or is unthreaded.

More will be explained later on a preferred embodiment of the first reversing phase.

In the second reversing phase of the backward movement RB the axial feed and the rotary movement of the tool become again 2 on each other according to the thread pitch P synchronized so as not to damage the thread, only that the direction of the axial feed is in the direction of the arrow of the backward movement RB opposite the direction of the arrow of the forward or working movement VB is interchanged or opposite and the direction of rotation of the rotary movement is also reversed, that is, instead of the forward direction of rotation VD, the reverse direction of rotation VR is now set.

The thread axis or center axis of the thread with the thread turn 50 is denoted by M and falls during the entire work movement, i.e. both in the first work phase and in the second work phase, and also during the reversing movement, i.e. both in the first reversing phase and in the second reversing phase, with the tool axis A. of the tool 2 together or is coaxial with this.

The 12th shows on the basis of a diagram an embodiment of a process (or: method) or a control sequence that can be used to generate a thread in the workpiece.

In the graph of the function T (cp) according to 12th is, without loss of generality, in particular the generation of a threaded hole, i.e. a complete thread generation cycle according to the invention in one embodiment, in particular a thread generation cycle with a first work phase, second work phase, reversal point, first reversing phase and second reversing phase, for example as already based on 1 to 10 described.

In the diagram of the 12th the penetration depth (or: vertical or axial coordinate) T is on the vertical axis or ordinate as in the axial direction, ie along the tool axis A. and that to the tool axis A. coaxial thread center axis M. , running and measured coordinates for the axial feed are plotted in mm. The values for the penetration depth T take from the value shown at the top, in particular the axial entry position on the workpiece surface 60 of the workpiece 6th corresponds to (which is also in 2 is shown) down to a lowest value, so are plotted as negative values downwards. The number range goes in the example of 1 for example from T = 0 mm as the uppermost value to, for example, T = - 17 mm as the lowest value, but of course other values are also possible depending on the desired thread length and tool design.

The (summed) angle of rotation is on the horizontal axis or abscissa φ the rotation of the tool 2 around its tool axis A. plotted in degrees [°]. The angle of rotation φ is based on the entry angle of rotation or initial angle of rotation φ = 0 ° at the axial entry position T = 0 mm at an entry point EP = (0, 0) and increases to the right towards positive values up to the value of entered on the abscissa as the last value φ = 8000 ° to. The angle of rotation φ increases with the forward rotational movement VD or in a forward direction of rotation towards positive values and decreases with the backward rotational movement RD or a reverse direction of rotation opposite to the forward direction of rotation. Here, ± 360 ° corresponds to one complete revolution of the tool 2 around its tool axis A. .

The function T (cp) describes the dependency or synchronization of the axial feed movement in the axial coordinate (or: depth in the workpiece 6th ) T of or with the rotary movement in the coordinate φ and is typically stored in a control such as a numerical control or CC control of the machine tool, in particular in the form of a previously determined and stored value table or also as a function for the respective calculation. According to the nomenclature commonly used in CNC technology, the T coordinate would correspond to the Z axis (spindle axis), with the positive direction running conventionally from the workpiece to the tool, such as in 1 at the coordinate T drawn.

The graph (cp; T ( φ )) of the function T (cp) proceeds according to 12th first of all a linear section that is typical of a tap or thread former and corresponds to the generation of the thread turn, ie in the form of a straight line, from the starting point φ = 0 ° and T = 0 mm up to a thread end point φ ₀ and T ( φ ₀ ), at which the thread turn or the actual thread generation ends and which in the example shown is - 16 mm without loss of generality.

mit der Gewindesteigung P.The representation of the linear function T (cp) in this section from φ = 0 to φ = φ ₀ and T = T (0), in particular 0 mm, to T = T (φ ₀ ), in particular - 16 mm applies: $$\left|\text{T}\left(\mathrm{\phi }\right)\right|=\left(\text{P /}360°\right)\mathrm{\phi }$$

with the thread pitch P .

The slope or derivative dT / dφ in this area is constant and corresponds to the amount according to P / 360 °. So that means for the thread pitch $$\text{P}=360°\left|\text{dT / d}\mathrm{\phi }\right|$$

Since in the example chosen the 12th that of the entered angle value φ = 3600 °, the corresponding value for the thread depth T = - 10 mm, the slope of the straight line is - 1 mm / 360 ° and thus the thread pitch P = 1 mm.

Due to the axial feed, which is synchronized with the rotation, along the penetration depth T or thread center axis M. are all components of the tool with a complete rotation of 360 ° 2 about the thread pitch P hiked on.

The linear portion of the function T ( φ ) corresponds to the usual synchronized tap or thread forming kinematics and can, for example, be already fixed in a CNC control programmed route condition (address letter G or G function), for example as G33, in particular G331 and G332, whereby the thread pitch P is entered as an interpolation parameter parallel to the Z-axis, typically under the address letter K in the CNC nomenclature.

The thread generation process takes place in this linear section, in particular for the generation of the thread turn 50 in the first working phase, from which in particular in 3 to 6th different positions or sections with increasing depth of penetration T are shown, and as a result becomes a thread of thread depth T _G as the interval length of the penetration depth T , in particular from T = 0 to T ₀ , over the interval length or the angle of rotation range φ _{G of} the angle of rotation φ , in particular from φ = 0 ° to φ = φ ₀ . In the example of the 12th the thread creation process (first working phase) takes place from φ = 0 ° to φ = φ ₀ and from the corresponding penetration depth T = 0 mm to T = - 16 mm.

The slope of the straight line in 12th between φ = 0 and φ = φ ₀ corresponds to the axial feed rate of the tool 2 that according to the thread pitch P on the angle of rotation φ is synchronized.

The time dependency of the angle of rotation φ (t) as a function of time t and thus penetration depth T (t) as a function of time t can in principle be varied during the thread production process - even over a wide range. However, the rotational speed is preferably dcp / dt and the axial feed speed dT / dt during the working movement VB always constant. If the rotational speed dcp / dt is changed, the axial feed speed dT / dt, i.e. the derivation of the penetration depth, must accordingly also be changed T after the time t be adjusted accordingly, so that the synchronization of the axial feed Z according to the relationship Z = P / 360 ° is retained.

This is the well-known kinematics implemented in machine tool controls or NC controls for thread generation by means of an axially working thread tool such as a tap or thread former.

Following the thread generation process (first work phase), a braking process or a braking movement now takes place, in particular in the second work phase FROM in a rotation angle range Δφ between the angle of rotation values φ ₀ and φ _n and an associated penetration depth range ΔT , which in the example of the 18th from T ( φ ₀ ) = - 16 mm to T ( φ _n ) = - 17 mm is sufficient. At the end of the braking movement FROM is a turning point UP achieved at which the tool 2 briefly comes to a standstill both in terms of the rotary movement and in terms of the axial feed movement. At the turning point UP are the maximum angle of rotation range φ _L , where φ _L = φ _G + Δφ , and the maximum depth of penetration T _L for the threaded hole 36 reached.

During the braking process or the braking movement FROM the axial feed speed is reduced depending on the angle of rotation, which corresponds to the slope of the graph shown for the function T (cp), according to a dependency or function that is preferably strictly monotonic (slope always falling) or monotonic (slope falling and possibly partially also zero), but may also temporarily increase slightly again in partial sections. The gradient is preferably set in a predetermined number n of individually defined, programmed or stored partial steps or braking steps S _i successively reduced, the total number or number n being a natural number with n> 1, generally 200>n> 2, in particular 20>n> 5 being selected, and where i is the counting index for the braking step S _i and lies between 1 and n, so 1 ≤ i ≤ n applies.

In every sub-step or braking step S _i is preferably a synchronization of the axial feed corresponding to the control of a threading process T (or from the feed rate dT / dt) and the angle of rotation φ (or the speed of rotation dφ / dt) set or programmed by adding each deceleration step S _i with 1 ≤ i ≤ n an associated predetermined function T _i ( φ ) is assigned or programmed with an associated value interval [T _i-1 , T _i ] over the associated angle of rotation interval [φ _i-1 , φ _i].

The function T _i (φ) is preferably linear, so the graph (idealized) is a straight line.

The programmed or saved incline decreases from each deceleration step S _i to the next braking step S _{i + 1} , gradually or successively, ie | dT _{i /} dφ | > 1 dT _{i + 1} / dφ |. The slope corresponds to a slope parameter.

In an advantageous embodiment, this pitch parameter is programmed as a thread pitch in the CNC control, that is to say in particular as an interpolation parameter along the z-axis or the thread axis M. in a G33, in particular G331 and G332, path condition. This means that the path conditions or G functions already specified in the control programming can be used and only the input parameter for the thread pitch needs to be successively changed or reprogrammed.

programmiert oder eingestellt, wobei $${\text{P}}_{\text{i+1}}<{\text{P}}_{\text{i}}$$

für alle i mit 1 ≤ i ≤ n. Ferner ist $${\text{P}}_{\text{i}}<\text{P}$$

d.h. die Steigung in der zweiten Arbeitsphase oder während der Abbremsbewegung AB kleiner ist als die Gewindesteigung P während der ersten Arbeitsphase. Insbesondere aber ohne Beschränkung der Allgemeinheit kann P_i = P (n - i)/n sein. Im Allgemeinen ist der letzte Wert P_n immer noch größer als 0, auch wenn er der kleinste Wert der Werte P_i ist.Thus, in every deceleration step S _i the associated slope parameter $${\text{P}}_{\text{i}}=\left|{\text{dT}}_{\text{i}}\text{/ d}\mathrm{\phi }\right|$$

programmed or set, where $${\text{P}}_{\text{i + 1}}<{\text{P}}_{\text{i}}$$

for all i with 1 ≤ i ≤ n. Furthermore, $${\text{P}}_{\text{i}}<\text{P}$$

ie the slope in the second work phase or during the braking movement FROM is smaller than the thread pitch P during the first phase of work. In particular, but without loss of generality, P _i = P (n - i) / n can be. In general, the last value P _n is still greater than 0, even if it is the smallest value of the values P _i .

The values of P _i can be selected, for example, in such a way that a continuously continued movement into the free cutting area is possible from the thread pitch movement. In particular, the speed of the tool should be maintained as far as possible. From this, for example, various conditions can be formulated that can be mapped in approximation functions.

für φ ∈ [φ_i-1, φ_i] mit den Randbedingungen T(φ_i-1) = T_i-1, und T(φ_i) = T_i.The following applies in every deceleration step S _i for all i with 1 ≤ i ≤ n the relation: $$\text{T}\left(\mathrm{\phi }\right)={\text{T}}_{\text{i-1}}-\left({\text{P}}_{\text{i}}\text{/}360°\right)\left(\mathrm{\phi }-{\mathrm{\phi }}_{\text{i}-1}\right)$$

for φ ∈ [φ _i-1 , φ _i ] with the boundary conditions T (φ _i-1 ) = T _i-1 , and T (φ _i ) = T _i .

The rotation angle range Δφ for the deceleration movement FROM in the second work phase is generally selected to be smaller than the angle of rotation range φ _G for thread generation in the first work phase, in particular Δφ <0.5 φ _G and preferably Δφ <0.2 φ _{G is} selected. This can depend in particular on how large the usable thread length is. Another influencing factor is the intended function in the undercut. If you want to make additional rotations in addition to the pure braking to cut the chips free, additional rotations can be added (see below on 21 and 22nd )

The penetration depth range (or: the maximum penetration depth) ΔT for the deceleration movement FROM In the second work phase, the selected range is generally smaller than the penetration depth range or the thread length T _G for thread creation in the first working phase, in particular ΔT <0.5 T _G , preferably ΔT <0.2 T _G elected.

The range of penetration ΔT for the deceleration movement FROM can in particular be chosen equal to P. There is also a penetration depth range ΔT Smaller P possible to keep the thread hole depth smaller, eg 0.5 P or 0.25 P. For machining reasons, it may also be advantageous to use larger undercut heights or a larger penetration depth range ΔT to choose, in particular up to 2 P and in exceptional cases also larger.

In one embodiment, a braking movement FROM in a rotation angle range Δφ and an associated penetration depth range ΔT Let n = 10 be chosen as an example and without loss of generality and are thus ten deceleration steps S ₁ to S ₁₀ with the associated slope parameters P ₁ to P ₁₀ intended.

The rotation angle range Δφ is divided accordingly into the n = 10 rotation angle intervals [φ ₀ , φ ₁ ], [φ ₁ , φ ₂ ], ..., [φ _i-1 , φ ₁ ], [ φ _i , φ _{i + 1} ], ... [φ ₉ , φ ₁₀ ] and associated with these intervals are the corresponding penetration depth intervals [T ₀ , T ₁ ], [T ₁ , T ₂ ], ..., [T _i-1 , T _i ], [ T _i , Ti + ₁ ], ..., [T ₉ , T ₁₀ ], into which the penetration depth range ΔT is divided, which in the example of the 12th from T ( φ ₀ ) = -16 mm to T (φ ₁₀ ) = - 17 mm is sufficient and / or corresponds to the thread pitch - P = - 1 mm. A partial step corresponds to each interval S _i .

It is now each of these intervals of each deceleration step S _i an associated pitch parameter P _i , in particular as a thread pitch or interpolation parameter of the CNC control, assigned to the two intervals [φ ₀ , φ ₁ ] and [ T ₀ , T ₁ ] the slope P ₁ , the pair of intervals [φ ₁ , φ ₂ ] and [T ₁ , T ₂ ] the slope P ₂ and so on up to the slope P ₁₀ for the last pair of intervals [φ ₉ , φ ₁₀ ] and [T ₉ , T ₁₀ ].

The slope values P ₁ to P ₁₀ are chosen such that P _{i + 1} , <P _i for i = 1 to i = n, in particular n = 10. In each subsection or braking step S _i remains the thread pitch P ₁ to P ₁₀ constant, so that there are essentially straight sections of the graph of the function T (cp), in which a synchronized “thread movement” takes place, i.e. the axial feed rate corresponds to the quotient of P _i / 360 °.

The penetration depth intervals in the braking steps are preferred S _i for all i with 1 i n (here, for example, n = 10) chosen to be the same, so that the length of the intervals T ₁ - T ₀ = T ₂ - T ₁ = T _i - T _i-1 = T _{i + i} - T _i = T _n - T _n-1 is chosen to be equal or equidistant, that is $${\text{T}}_{\text{i}}-{\text{T}}_{\text{i-1}}=\Delta \text{T / n}\text{.}$$

in dem Drehwinkelbereich Δφ in den Abbremsschritten S_i . D.h. der Drehwinkelabstand φ₂ - φ₁ ist kleiner als der Drehwinkelabstand φ₃ - φ₂ und der Drehwinkelabstand φ_i+1 - φ_i ist größer als der Winkelabstand φ_i - φ_i-1. Den größten Winkelabstand oder Winkelbereich deckt der letzte Teilabschnitt ab zwischen den Drehwinkelwerten φ₁₀ - φ₉ . Dies entspricht einem kontinuierlichen und in jedem Teilabschnitt oder Abbremsschritt S_i verlangsamten Abbremsvorgang.Since the axial feed is chosen to be constant in each sub-section or sub-interval in this exemplary embodiment, since T _{i + i} - T _i is chosen to be the same or equidistant for all i, result with less increasing slope P _i and thus decreasing axial feed speed increasing rotation angle intervals φ _{i + 1} - φ _i $${\mathrm{\phi }}_{\text{i}+1}-{\mathrm{\phi }}_{\text{i}}>{\mathrm{\phi }}_{\text{i}}-{\mathrm{\phi }}_{\text{i}-1}$$

in the rotation angle range Δφ in the deceleration steps S _i . That is, the angle of rotation distance φ ₂ - φ ₁ is smaller than the angle of rotation _{distance φ 3} - φ ₂ and the angle of rotation _{distance φ i + 1} - φ _i is greater than the angular distance φ i - φ _i-1 . The last section between the rotation angle values covers the largest angular distance or angular range φ ₁₀ - φ ₉ . This corresponds to a continuous and in each partial section or braking step S _i slowed braking process.

During the deceleration movement FROM the time dependency of the rotational speed dcp / dt and the axial feed speed dT / dt is selected or controlled or programmed in such a way that the tool 2 at the turning point UP = (φ _n , T _n ) or (φ ₁₀ , T ₁₀ ) comes to rest, i.e. dcp / dt = 0 and dT / dt = 0 with φ = φ _n or T = T _n or with φ = φ ₁₀ or T = T ₁₀ . The tool 2 at the turning point UP is also in 7th shown.

The reduction of the rotational speed dcp / dt and the axial feed speed dT / dt to 0 depending on the time t can, for example, be continuous during the braking movement FROM take place or, for example, only in the last braking step S _n or S ₁₀ .

From the inertia of the drive system, in particular of the control and the machine drives and the inertia of the moving components, the graphs in the braking steps are not exactly linear, but rather slightly rounded S ₁ to S ₁₀ or during the braking movement FROM . Ideally represented or stored in the programming of the braking movement itself, however, the described sequence of linear functions or strung together linear sections with gradually decreasing slope, ie gradually decreasing constant feed rate, results in the individual braking steps S _i for example S ₁ to S ₁₀ .

Before initiating an extension or reversing movement, an intermediate step can be carried out, such as a cleaning process. Here you can, for example, remove the remains of the chip roots by turning the tool further, or you can clean the circumferential groove of remnants of the thread tips in order to get a cleaner cylindrical area. Then a screw could be screwed in even better.

After reaching the turning point UP is now in one embodiment, as in particular in 12th shown, a reversing movement or backward movement RB initiated, which initially in a first reversing phase, an acceleration movement BB includes up to the threading into the thread 50 what for example in 8th is shown, and in a second reversing phase, a backward movement RB in which the tool 2 through the thread 50 synchronized to the outside, which is, for example, in 9 is shown.

In an advantageous embodiment, the control curve or function can now according to 12th in reverse order and / or symmetrically to the reversal point UP used or traversed.

The rotary motion is used for the backward motion RB or. BB reversed from the forward direction of rotation VD to the reverse direction of rotation RD, ie the angle of rotation φ starting from φ = φ _n or φ = φ _10, preferably at the reversal point UP reduced or turned back in the negative direction until finally the starting value again φ = 0 is reached and the tool 2 from the workpiece 6th exit. The dependency or function T (cp), which is preferably adopted unchanged, now leads to the penetration depth T becomes smaller in terms of amount with decreasing angle of rotation, i.e. from T = T _n or T = T ₁₀ at the reversal point UP again up to T = 0 at the entry point EP at φ = 0 decreases, which is therefore also the exit point at the same time. In particular, the first reversing phase corresponds to the second work phase and the second reversing phase corresponds to the first work phase.

In particular, an embodiment can also be used for the second working phase in reversed order for the first reversing phase. It can therefore start from the reversal point in the first reversing phase UP the same dependency or function T ( φ ) in the opposite order for the acceleration movement BB in reverse of the braking movement FROM be used.

However, other functions T ( φ ) and sub-steps are used, which preferably correspond to the point ( φ ₀ , T ₀ ), at which the decelerating movement FROM began or the first work phase ended, so that the correct threading point for the tool for the retraction through the thread 50 can be achieved.

Preferably, starting from the final angle value φ _n or φ ₁₀ in reverse order initially an acceleration phase as the first reversing phase with an acceleration movement BB carried out with the same incremental steps. These steps are now, however Are acceleration steps S _j with n + 1 j 2 n, starting with S ₁₁ to S ₂₀ for n = 10.

Associated with each of these acceleration steps S _{j is} an associated angle of rotation interval [ φ ₁₀ , φ ₁₁ ], [φ ₁₁ , φ ₁₂ ], ..., [φ _j-1 , φ _j ], [φ _j , φ _{i + 1} ], ... [φ ₁₉ , φ ₂₀ ], where φ _j from the first reversing phase simply φ _i from the second work phase corresponds if one sets i + j = n. The slope parameters also stay the same, just in reverse order, so they are from P ₁₀ via P ₉ , P ₈ up to P ₁ for the sections of the control curve according to 12th scroll from right to left until the depth value T ₀ is achieved. There is a new angle value φ ₁₁ temporally after the angle value φ ₁₀ assumed and the interval [ φ ₁₀ , φ ₁₁ ] the interval [T ₁₀ , T ₉ ], with the thread pitch P ₁₀ and the subsequent angular interval [φ ₁₁ , φ ₁₂ ] the penetration depth _{interval [T 9} , T ₈ ] with the corresponding thread pitch P ₉ etc. up to the last section of [φ ₁₉ , φ ₂₀ ] corresponding to [T ₁ , T ₀ ] with the thread pitch P ₁ .

Then, in the opposite direction, the 12th the linear portion of the curve of φ ₀ to φ = 0 according to the penetration depth T from T ₀ traverse up to T = 0. The slope of the straight line in 12th The corresponding axial feed rate during the backward movement is now again P / 360 ° with the opposite direction. As a result, the tool is guided in reverse through the thread generated in the forward movement, without the thread turn being damaged in the thread. The backward movement is synchronized in exactly the same way as the forward movement, only with the opposite direction of rotation, so that the angle changes φ from the angle φ _n just backwards again in its value decreases up to φ = 0 and now the thread depth of T = even if the axial feed rate is reversed T ₀ until T = 0 increases mathematically.

The same control curve or function T (cp) as in the forward movement VB in the two working phases also in the backward movement RB Using it in the two reversing phases has the advantage, on the one hand, that the tool 2 Can be controlled precisely in position or movement and is particularly useful when threading into the thread 50 is in the correct position, and so the forces during reversing can be kept very low and / or a high retraction or extension speed is made possible.

In one embodiment of an implementation of the described dependencies or functions for T ( φ ) are the values of the penetration depth T is used as input parameters measured or specified by the control system or programming, and the associated values of the angle of rotation are obtained φ from the dependency by means of the assigned slope parameters P and P _i .

An NC program for tapping or thread forming can therefore be selected, in particular with a G33, in particular G331 and G332, path condition with a thread pitch to be entered, and a sequence or set of values for the penetration depth can now be specified for which a new Thread pitch parameter is switched, the thread pitch parameter being retained until the next value of the penetration depth.

The 13th now shows an embodiment of a braking movement FROM in an enlarged view of the lower right area of the diagram of FIG 12th in a rotation angle range Δφ and an associated penetration depth range ΔT .

In 13th n = 10 is selected as an example and without loss of generality, and there are thus ten deceleration steps S ₁ to S ₁₀ with the associated slope parameters P ₁ to P ₁₀ drawn.

The rotation angle range Δφ is divided accordingly into the n = 10 rotation angle intervals [φ ₀ , φ ₁ ], [φ ₁ , φ ₂ ], ..., [φ _i-1 , φ ₁ ], [φ _i , φ _{i + 1} ],. .. [φ ₉ , φ ₁₀ ] and associated with these intervals are the corresponding penetration depth intervals [T ₀ , T ₁ ], [T ₁ , T ₂ ], ..., [T _i-1 , T _i ], [T _i , Ti + ₁ ], ..., [T ₉ , T ₁₀ ], into which the penetration depth range ΔT is divided, which in the example of the 12th from T ( φ ₀ ) = -16 mm to T (φ ₁₀ ) = - 17 mm is sufficient and / or corresponds to the thread pitch - P = - 1 mm. A partial step corresponds to each interval S _i .

In 13th is different from in 12th , the differential angle of rotation based on φ ₀ recorded. If you are in 13th the same values on the rotation angle axis for φ as in 12th want to enter, all values on the horizontal axis are with the value of φ ₀ who is in 12th is for example 5800 °, to be added. The deceleration movement FROM starts at the angle of rotation value φ ₀ and the corresponding penetration depth value T ₀ and ends at the final angle of rotation value φ ₁₀ and the associated penetration depth value T ₁₀ .

It is now each of these intervals of each deceleration step S _i an associated pitch parameter P _i , in particular as a thread pitch or interpolation parameter of the CNC control, assigned to the two intervals [φ ₀ , φ ₁ ] and [ T ₀ , T ₁ ] the slope P ₁ , the pair of intervals [φ ₁ , φ ₂ ] and [T ₁ , T ₂ ] the slope P ₂ and so on up to the slope P ₁₀ for the last pair of intervals [φ ₉ , φ ₁₀ ] and [T ₉ , T ₁₀ ].

The slope values P ₁ to P ₁₀ are chosen such that P _{i + 1} <P _i for i = 1 to i = 10 in 13th or n in 12th . In every section or braking step S _i remains the thread pitch P ₁ to P ₁₀ constant, so that there are essentially straight sections of the graph of the function T (cp), in which a synchronized “thread movement” takes place, i.e. the axial feed rate corresponds to the quotient of P _i / 360 °.

im dargestellten Ausführungsbeispiel der 13 als - 1 mm/10 = - 0,1 mm gewählt ist.In the illustrated embodiment of 13th became the penetration depth intervals in the deceleration steps S _i for all i with 1 i n (here, for example, n = 10) chosen to be the same, so that the length of the intervals T ₁ - T ₀ = T ₂ - T ₁ = T _i - T _i-1 = T _{i + i} - T _i = T _n - T _n-1 is chosen to be equal or equidistant, that is $${\text{T}}_{\text{i}}-{\text{T}}_{\text{i-1}}=\Delta \text{T / n}$$

in the illustrated embodiment of 13th is selected as - 1 mm / 10 = - 0.1 mm.

in dem Drehwinkelbereich Δφ in den Abbremsschritten S_i . D.h. der Drehwinkelabstand φ₂ - φ₁ ist kleiner als der Drehwinkelabstand φ₃ - φ₂ und der Drehwinkelabstand φ_i+1 - φ_i ist größer als der Winkelabstand φ_i - φ_i-1. Den größten Winkelabstand oder Winkelbereich deckt der letzte Teilabschnitt ab zwischen den Drehwinkelwerten φ₁₀ - φ₉ . Dies entspricht einem kontinuierlichen und in jedem Teilabschnitt oder Abbremsschritt S_i verlangsamten Abbremsvorgang.Since the axial advance in each section or sub-interval in the embodiment of 13th is chosen to be constant, since T _{i + 1} - T _i is chosen to be the same or equidistant for all i, with a decreasing slope P _i and thus decreasing axial feed rate, increasing rotation angle intervals φ _{i + 1} - φ _i $${\mathrm{\phi }}_{\text{i}+1}-{\mathrm{\phi }}_{\text{i}}>{\mathrm{\phi }}_{\text{i}}-{\mathrm{\phi }}_{\text{i}-1}$$

in the rotation angle range Δφ in the deceleration steps S _i . Ie the angle of rotation distance φ ₂ - φ ₁ is smaller than the angle of rotation distance φ ₃ - φ ₂ and the angle of rotation distance φ _{i + 1} - φ _i is greater than the angular distance φ _i - φ _i-1 . The last section between the rotation angle values covers the largest angular distance or angular range φ ₁₀ - φ ₉ . This corresponds to a continuous and in each partial section or braking step S _i slowed braking process.

During the deceleration movement FROM the time dependency of the rotational speed dcp / dt and the axial feed speed dT / dt is selected or controlled or programmed in such a way that the tool 2 at the turning point UP = φ _n , T _n ) or (φ ₁₀ , T ₁₀ ) comes to rest, i.e. dcp / dt = 0 and dT / dt = 0 with φ = φ _n or T = T _n or with φ = φ ₁₀ or T = T ₁₀ .

The reduction of the rotational speed dcp / dt and the axial feed speed dT / dt to 0 depending on the time t can, for example, be continuous during the braking movement FROM take place or, for example, only in the last braking step S _n or S ₁₀ .

The really not exactly linear, but somewhat rounded curves of the graphs in the braking steps S ₁ to S ₁₀ of the 13th physically follow from the inertia of the drive system, especially the control, including its interpolation routines to smooth the transitions, and the machine drives and the inertia of the moving components.

Ideally represented or stored in the programming of the braking movement itself, however, the described sequence of linear functions or strung together linear sections with gradually decreasing slope, ie gradually decreasing constant feed rate, results in the individual braking steps S _i for example S ₁ to S ₁₀ .

In 14th an embodiment is shown, as in the first reversing phase starting from the reversal point UP the same dependency or function T ( φ ) in the opposite order for the acceleration movement BB in reverse of the braking movement FROM e.g. according to 12th and 13th can be used.

However, other functions T ( φ ) and substeps as in 5 can be used, preferably to the point ( φ ₀ , T ₀ ,) to which also the braking movement FROM began or the first work phase ended, so that the correct threading point for the tool for the retraction through the thread 50 can be achieved.

Preferably, starting from the final angle value φ _n or φ ₁₀ in reverse order initially an acceleration phase as the first reversing phase with an acceleration movement BB carried out with the same incremental steps. However, these steps are now acceleration steps S _j with n + 1 j 2 n, in 14th starting with S ₁₁ to S ₂₀ for n = 10.

Associated with each of these acceleration steps S _{j is} an associated angle of rotation interval [φ ₁₀ , φ ₁₁ ], [φ ₁₁ , φ ₁₂ ], ..., [φ _j-1 , φ _j ], [φ _j , φ _{i + 1} ], ... [φ ₁₉ , φ ₂₀ ], where φ _j from the first reversing phase is simple φ _i from the second work phase corresponds if one sets i + j = n. The slope parameters also remain the same, only in reverse order, i.e. in 5 they will from P ₁₀ via P ₉ , P ₈ up to P ₁ for the sections of the control curve according to 13th scroll from right to left until the depth value T ₀ is achieved. According to 14th becomes the new angle value φ ₁₁ chronologically after the angle value φ ₁₀ assumed and corresponds to the interval [ φ ₁₀ , φ ₁₁ ] the interval [T ₁₀ , T ₉ ], with the thread pitch P ₁₀ and the subsequent angular interval [φ ₁₁ , φ ₁₂ ] the penetration depth _{interval [T 9} , T ₈ ] with the corresponding thread pitch P ₉ etc. up to the last section of [φ ₁₉ , φ ₂₀ ] corresponding to [T ₁ , T ₀ ] with the Thread pitch P ₁ .

Then, in the opposite direction, the 12th the linear portion of the curve of φ ₀ to φ = 0 according to the penetration depth T from T ₀ traverse up to T = 0. The slope of the straight line in 1 The corresponding axial feed rate during the backward movement is now again P / 360 ° with the opposite direction. As a result, the tool is guided in reverse through the thread generated in the forward movement, without the thread turn being damaged in the thread. The backward movement is synchronized in exactly the same way as the forward movement, only with the opposite direction of rotation, so that the angle changes φ from the angle φ _n just backwards again in its value decreases up to φ = 0 and also when the axial feed rate is reversed, the thread depth now increases from T = T ₀ to T = 0 from a mathematical point of view.

The same control curve or function T (cp) as in the forward movement VB in the two working phases also in the backward movement RB Using it in the two reversing phases has the advantage, on the one hand, that the tool 2 Can be controlled precisely in position or movement and is particularly useful when threading into the thread 50 is in the correct position, and so the forces during reversing can be kept very low and / or a high retraction or extension speed is made possible.

In one embodiment of an implementation of the described dependencies or functions for T ( φ ) are the values of the penetration depth T is used as input parameters measured or specified by the control system or programming, and the associated values of the angle of rotation are obtained φ from the dependency by means of the assigned slope parameters P and P _i .

A CNC program for tapping or thread forming can therefore be selected, in particular with a G33, in particular G331 and G332, path condition with a thread pitch to be entered, and a sequence or set of values for the penetration depth can now be specified for which a new Thread pitch parameter is switched, the thread pitch parameter being retained until the next value of the penetration depth.

A sequence would be e.g.

Work assessment:

• ■ Bei der Eindringtiefe T = 0 wähle den Gewindesteigungsparameter P und behalte diesen bis T = T₀ bei. Es wird eine Drehzahl oder Drehgeschwindigkeit eingestellt.
• ■ Bei T = T₀ wechsle auf den Gewindesteigungsparameter P₁ und behalte diesen bis T = T₁ bei.
• ■ Bei T = T_i wechsle auf den Gewindesteigungsparameter P_i+1 und behalte diesen bis T = T_i+1 bei für alle i mit 1 ≤ i ≤ n.
• ■ Reduziere die Drehgeschwindigkeit oder Drehzahl bis auf 0 bei T = T_n .

und vorzugsweise für die

• ■ The depth of penetration T = 0 choose the thread pitch parameter P and keep this until T = T ₀ at. A speed or rotational speed is set.
• ■ At T = T ₀ change to the thread pitch parameter P ₁ and keep it until T = T ₁ .
• ■ At T = T _i change to the thread pitch parameter P _{i + 1} and keep this until T = T _{i + 1} for all i with 1 ≤ i ≤ n.
• ■ Reduce the rotational speed or rotational speed down to 0 at T = T _n .

and preferably for that

Reversing movement:

• ■ At T = T _n reverse the axial feed movement and the rotary movement with a set rotational speed or rotational speed and start again in the opposite direction with the thread pitch parameter P _n and maintain this until T = T _n-1 .
• ■ At T = T _j change to the thread pitch parameter P _j and keep this until T = T _j-1 for all j as a descending index with 1 j-n-1.
• ■ At T = T ₀ choose the thread pitch parameter P and keep this until T = 0.

Even if this embodiment of the working movement in the second working phase and / or the reversing movement in the first reversing phase, which corresponds in particular to a linear interpolation, has advantages due to its simple implementation in existing machine programs, other dependencies or functions or Interpolations in individual sub-steps or sub-intervals for the relationship between T and φ can be provided or combinations thereof.

In the described linear interpolation, the linear curve sections or graph sections are continuously attached to one another, i.e. the starting points ( φ _i , T _i ) of each interval correspond to the endpoints of the previous interval and for the first interval the endpoint ( φ ₀ , T ₀ ) of the linear graph of thread generation. These connection points are also referred to as support points.

In all embodiments or interpolations, instead of linear sections, curve sections or graph sections can also be selected that are continuously differentiable juxtaposed (or: linked, connected to one another). This means that not only does the starting point of each interval coincide with the end point of the previous interval, i.e. a continuous transition takes place at the connection points between the intervals, but also the graph sections or their functions in these Connection points are differentiable and their derivatives have the same value. As a result, smooth or continuously differentiable transitions between the graphs in the individual deceleration steps or intervals are achieved, which is beneficial to the sequence of movements. Also the transition in the angle of rotation φ ₀ from the thread generating movement in the first working phase to the braking movement FROM in the second working phase or then, accordingly, preferably also from the first reversing phase to the second reversing phase, it is preferably continuously differentiable or selected with the same gradient

Examples of functions that are suitable for such a continuously differentiable interpolation are polynomials of degree higher than 1, in particular third degree, such as, for example, cubic splines.

mit den bei Spline-Interpolation üblichen Randbedingungen lässt sich beispielsweise eine bis in die dritte Ableitung stetige Funktion erstellen.Spline interpolation can be used here. Using a 3rd degree polynomial function as a spline function $$\text{T}\left(\mathrm{\phi }\right)={\text{a}}_3{\mathrm{\phi }}^3+{\text{a}}_2{\mathrm{<figure-callout\; id="2"\; label="\phi "\; filenames="DE102019124800A1\_0016.png,DE102019124800A1\_0017.png"\; state="\{\{state\}\}">\phi </figure-callout>}}^2+{\text{a}}_{\text{1}}\mathrm{\phi }+{\text{a}}_0$$

With the general conditions usual for spline interpolation, for example, a function that is continuous up to the third derivative can be created.

Furthermore, a continuous, in particular strictly monotonically or also monotonically decreasing function for the braking process or at least a predominant part of the braking steps can also be used S _i , for example an exponential function or logarithmic function, can be used

wobei fd der Flankendurchmesser ist und x eine fortlaufende natürliche Zahl.For example, the following exponential function can be used: $$T=-e^{\frac{-P}{\pi \cdot fd}\cdot x}+1;$$

where fd is the pitch diameter and x is a running natural number.

The theoretical curves or functions described can in particular be mapped by a corresponding number of individual NC control data records.

In a further embodiment of an implementation of the described dependencies or functions for T ( φ ) are the values of the angle of rotation φ used as input parameters measured or specified by the control system or programming, and the associated values of the penetration depth result T from the dependency by means of the slope parameters P and P _i .

In a third variant, the time can also be specified as an input parameter and the values of the angle of rotation φ (t) and the penetration depth T (t) result from the dependence on time t and the dependence on each other by means of the slope parameters P and P _i .

In one embodiment, the control or synchronization can take place in an open control or control circuit without measuring the process variables, penetration depth and angle of rotation. A penetration depth value is assigned to each angle of rotation value by means of a table of values or by calculation according to the stored formulas, and the rotary drive and axial drive are controlled accordingly.

In a further embodiment, at least one of the two process variables penetration depth and angle of rotation can also be measured, and the measured values can be fed back into the controller in order to carry out a regulation, for example in accordance with the method in 12th target curve shown, to be realized in a closed control loop. The angle of rotation φ is usually determined in the area of the drive, in particular the drive spindle, by means of rotation angle sensors or measurement of physical quantities that are clearly related to the rotation angle. In principle, however, it is also possible to set the angle of rotation directly on the tool 2 to eat.

The depth of penetration T can be measured by axial position sensors and here again generally on the drive, in particular the drive spindle, or in a special embodiment on the tool or workpiece itself.

In further embodiments, an equalization step or constant circulation step can also take place in the second work phase, during which the penetration depth T ( φ ) = const. is or at least no further feed movement is carried out in the forward direction. The direction of rotation of the rotary movement preferably remains the same during the equalization step, ie it is not reversed.

In one embodiment, when the maximum penetration depth is reached ΔT at an angle of rotation φ _n-1 the corresponding value T ( φ ) for the subsequent step S _n up to the angle of rotation φ _n at the turning point UP held constant, ie T (φ _n-1 ) = T _n-1 = T _n = T ( φ _n ).

In a further embodiment, the maximum penetration depth ΔT already reached at an angle of rotation φ _n-2 with the corresponding value T (φ _n-2 ) = T _n-2 . Now the value T (cp) for the subsequent step S _{n-1 is} reduced again up to the angle of rotation φ _n-1 , ie the axial advance direction vice versa, and the penetration depth is reduced to the value T (φ _n-1 ) = T _n-1 <T _n-2 . The tool therefore runs with a slight reversing feed in the circumferential groove. This defined movement in the negative T-direction away from the bottom of the hole can be advantageous in order to further improve the undercut or the circumferential groove with regard to screwability. From the angle of rotation φ _n-1 , the corresponding value T ( φ ) for the subsequent step S _n up to the angle of rotation φ _n at the turning point UP held constant, ie T (φ _n-1 ) = T _n-1 = T _n = T ( φ _n ). However, especially when the circumferential groove has already been (largely) created, a relatively large and / or rapid return movement and / or an axial back and forth movement of the tool during leveling can also take place, which can also have an axial advance per 360 °, which even greater than the thread pitch P is.

The tool and its thread teeth thus rotate in step S _n on a circular path or cylindrical path without a gradient or even in step S _n-1 with a positive gradient again by a small amount outwards in the workpiece.

This movement serves in particular to level the circumferential groove and to clean the surface of the workpiece, to evacuate the created threaded hole as completely as possible from chip material and, if necessary, to reduce tension between the workpiece and the tool that were previously built up by the machining forces. The step S _n as the last step of the braking movement FROM as well as the penultimate step S _n-1 can thus also be referred to as an equalization step.

The total angle of rotation φ _n - φ _n-1 , of the equalization step S _n or φ _n - φ _{n-2 of} the equalization step S _n and S _n-1 can be freely selected within wide limits, for example between 180 ° and 2000 °, and is usually selected to be larger, for example 3 times larger, than the angle of rotation φ _{n- 1} - φ ₀ or φ _n-2 - φ ₀ of the previous monotonically falling section (transition area).

During the reversing movement RB In the first reversing phase, for example, the equalization step can also be partially or completely omitted.

By means of the measures according to the invention, advantageous sequences of movements can be achieved in the transition into the free cut (circumferential groove) and in the free cut itself. The working speed of the tool can be as high and constant as possible. The machine (including control) can map the movement in a highly dynamic manner. A geometry that can be screwed through can also be created in the cutout or the circumferential groove.

If you look at the conditions on the machine, you can see that there is a physical inertia in the system as well as an inertia in the drives and in the control system. In order to keep the speed from the thread high also in the undercut, ie the circumferential groove, a constant movement path of the z-axis (variable T ) and axis of rotation (variable φ ) enables the machine to implement this movement, preferably at a high path speed. This then results in a high and steady speed of the effective tool teeth and cutting edges. This, in turn, is beneficial for uniform machining.

In order to program the machine, the theoretical trajectories can be transferred to corresponding NC blocks. Here, slight deviations or approximations (in the form of, for example, compound helical movements) can occur.

In the technical implementation of a thread production process like this one, the time dependency of the penetration depth is also important T = T (t) and the angle of rotation φ = φ (t) or the speed or frequency n = n (t) from the time t. This defines the path speed v (t) (circumferential speed, machining speed, feed speed, cutting speed) resulting on the workpiece, i.e. the speed in the tangential direction to the trajectory.

The path speed v (t) depends on the radius r and thus the thread hole diameter, on the one hand, and the rotational speed ω (t) = dφ (t) / dt = 2 π n (t) according to the vector relationship v = r × ω and is therefore for larger radii r larger at the same speed n, e.g. larger for M8 threads (r = 4 mm) than for M6 threads (r = 3 mm).

_{Ideally, an at least approximately constant maximum path speed v max should be} achieved or maintained for as long as possible or for as long a period of time as possible during the process. This applies in particular to the braking movement or undercut movement FROM .

The tool is generally optimized with regard to its performance and geometry to this maximum value v _max . This maximum path speed v _max corresponds to an at least approximately constant maximum speed nmax, which, however, depends on the radius or diameter of the tool, as already described.

According to the EMUGE manual, pages 282 to 283, different cutting speeds should also be selected for tapping, depending on the material of the workpiece and the material of the tap (solid carbide or HSS), e.g. from 40 to 100 m / min. in not hardened Steels and from 5 to 80 m / min. in cast iron and from 10 to 60 m / min. in aluminum alloys for the various types of taps specified there.

After extensive experiments and investigations by the inventors, values for the web speed v _max from a value range from 57 m / min to 189 m / min, in particular from 85 m / min to 132 m / min, have finally proven to be particularly useful, especially in aluminum materials.

The following preferred speed ranges in rpm (1 / min = 1/60 Hz) for the maximum speed are derived from these web speed ranges.

With an M6 thread (diameter 6 mm), the maximum speed nmax of the tool is between 3,000 rpm and 10,000 rpm, preferably between 4,500 rpm and 7,000 rpm.

With a different thread diameter, the speed or the speed range changes according to the ratio of 6 mm to the other thread diameter, for example with M8 instead of M6 by the factor 6th / 8 = 0.75.

With an M8 thread (diameter 8 mm), for example, the maximum speed nmax of the tool is between 2,250 rpm and 7,500 rpm, preferably between 3,375 rpm and 5,250 rpm.

Technically, as already stated, a primary target specification or process condition is both during thread creation, i.e. the first work phase with the work movement VB , as well as and especially during the undercut movement, i.e. the second work phase with the braking movement FROM to achieve or keep the desired path speed and thus the maximum speed as constant as possible for as long as possible. In other words, the longest possible periods of time during the work movement, including the second work phase (undercut movement), should ensure the longest possible plateau with the maximum speed in the time-dependent function of the speed n (t). In this way, the process can be operated as long as possible at the maximum speed that is optimal for the tool and excessive forces and accelerations on the tool can be avoided.

In addition, in a further target specification or process condition, the maximum speed should already be reached when entering the workpiece at a predetermined safety distance.

It has now surprisingly been found that at the preferred maximum speeds of 4,000 rpm to 6,000 rpm, especially for M6 and M8, even with this high-end machine equipment, the undercut movement does not achieve a constant maximum speed and thus path speed could be, which led to reduced tool life up to and including tool breakage. The following error, i.e. the offset between the setpoint and the actual value of the axis position, increases with increasing speed in machine tools. This error can be counteracted by increasing the Kv factor, which indicates the speed at which the following error is closed. However, there are limits to increasing the Kv factor, otherwise the machine's control system will become unstable, overshoots will occur and the machine will begin to vibrate.

In one embodiment, the invention is based on the idea of interposing or arranging a transmission unit between the spindle of the machine and the tool, which translates the speed of the machine spindle to a higher speed on the tool with a predetermined transmission ratio of at least 1: 3. The speed at the machine spindle is equal to the product of the transmission ratio and the speed of the tool. With this measure, it was surprisingly possible to achieve a sufficient speed plateau with the maximum speed both during the first work phase (thread generation) and during the second work phase (undercut or circumferential groove generation).

The transmission ratio is generally chosen between 1: 3 and 1:10, in particular between 1: 4 and 1: 8, preferably between 1: 4 and 1: 5. It turned out that higher gear ratios did not bring any significant further improvements.

If machine tool controls should also achieve the stated objectives, even without a translation unit, such designs also fall under the implementation of the invention and its scope of protection.

In embodiments based on 15th and 16 the difference becomes clear with and without a translation unit. An exemplary embodiment of the translation unit used is shown in 17th shown.

The thread creation cycle of the 15th was carried out according to the invention with a translation unit between the machine drive or the machine spindle of the machine tool and tool. The gear ratio the translation unit, which is the ratio of the speed or the rotational speed of the drive, in this case the machine drive or the machine spindle, to the rotational speed or the rotational speed of the output, in this case the tool 2 or its tool holder, is selected to be less than one, ie the translation takes place quickly. In the example shown, the 16 a translation unit has been chosen with a ratio of approximately 4.4 by an inventively modified Speed Synchro was used ^® by the applicant. A maximum spindle speed of 1,020 rpm = 17 1 / s = 17 Hz was set, corresponding to a tool speed of 4,500 rpm = 75 1 / s = 75 Hz

The thread creation cycle of the 16 was carried out without a translation unit between the machine spindle of the machine tool and the tool, ie the spindle speed corresponded to that of the tool. A maximum spindle speed of 4,500 rpm = 75 1 / s = 75 Hz was set.

In 15th and 16 are empirically determined time dependencies or controls of the penetration depth T = T (t) or z-axis coordinate on the one hand and the speed n = n (t) as a function of time t over the entire thread generation cycle between the entry point EP and the reversal point UP and back again. The penetration depth T (t) = T (cp (t)) results as a function of time t due to the selected dependency T (cp), which has already been described in detail. The speed n (t) depends on the angular speed ω = ω (t) = dcp / dt, which is the first time derivative of the angle of rotation of the angle of rotation φ = φ (t) corresponds, together as follows, to 2π n (t) = dcp / dt. The angular speed ω or the speed n (t) and the axial speed v (t) are synchronized again, in particular according to one embodiment 12th .

The speed n (t) in 15th Two different speeds plotted against time, on the one hand the speed n _w (t) of the tool 2 and on the other hand the speed n _s (t) of the machine spindle.

der Übersetzungseinheit miteinander verknüpft. Das Übersetzungsverhältnis I ist im Allgemeinen größer als 3 gewählt, im vorliegenden Ausführungsbeispiel der 16 beträgt das Übersetzungsverhältnis I der Übersetzungseinheit etwa I = 4,4.The two speeds n _w (t) and n _s (t) are based on the transmission ratio $$\text{I.}={\text{n}}_{\text{s}}\left(\text{t}\right){\text{/ n}}_w\left(\text{t}\right)$$

linked to the translation unit. The transmission ratio I is generally selected to be greater than 3, in the present exemplary embodiment FIG 16 the transmission ratio I of the transmission unit is approximately I = 4.4.

In 16 on the other hand, only one speed is plotted against time as speed n (t), namely the speed nw (t) of the tool 2 , because because of the missing translation unit, the speed is nw (t) of the tool 2 and the speed n _s (t) of the machine spindle is the same, ie n _s (t) = nw (t).

On the timeline of time t are in 15th and 16 eleven points in time to to t _{10 are} plotted.

The earliest point in time t ₀ corresponds to the start of the thread generation cycle at entry point EP. The entry point EP lies at T (to) on the workpiece surface and is spaced by a safety distance here, for example - 2 mm from T = 0 mm, at which the movement in the z-axis begins. The first work phase of the work movement begins at time to VB at which the thread is created. Here, the penetration depth T (t) is synchronized with the angle of rotation φ (t) or the speed n (t) via the thread pitch, for example in 12th shown. For example, the 5 and 6th where the thread creation area 4th the thread 50 generated.

This first working phase ends at time t ₂ and the undercut movement or braking movement goes into the second working phase FROM over. Here at T (t ₂ ) is the thread depth T _G reached, which in the present case is, for example, about 11 mm.

In the second work _{phase between time t 2} and time t ₅ , the braking movement or undercut movement takes place FROM instead of that at the turning point UP ends. The penetration depth T (t) decreases, becoming significantly slower, around the penetration depth area ΔT = T (t ₅ ) - T (t ₂ ) down to the lowest value T (t ₅ ) at the reversal point UP (in terms of amount), which in the example shown is -14 mm. Here is the thread hole depth T _L reached. Starting at time t ₂ to time t ₅ , which is the turning point UP corresponds, so the braking process or the undercut movement to generate the circumferential groove (s) or undercuts, in particular 51 in 1 and 10 as well as 51 and 52 in 11 , instead, especially the braking movement FROM according to 12th and 13th and / or the braking movement with the predetermined dependency according to the invention between the penetration depth T = T ( φ ) and the angle of rotation φ (not to be confused with the curve T (t) in 15th and 16 ). During the braking process in the embodiment according to changes 12th the depth of penetration ΔT and the angle of rotation around Δφ .

Specifically, a change in the thread pitches Pi at intervals of 0.1 mm each can be set with programmed thread commands G331 with a pitch range of 0.9 mm - 0.05 mm (thread itself has P = 1 mm). Machine-internal routines usually interpolate the commands entered into a continuous curve for each axis. Due to the reduced gradients in the undercut movement, in particular the chip root in the drill base is reduced in size until it no longer represents an obstacle in the backward movement.

At the turning point UP the penetration depth T (t) reaches its deepest and largest value in terms of absolute value T _L and the angle of rotation φ (t) also has its largest or widest value φ _L. The axial speed v (t) = dT / dt and the speed n (t) = dcp / dt / 2π take place at the reversal point UP currently shows the value zero, i.e. the tool 2 comes to a standstill here, for example in 7th shown.

From the turning point UP the reversing movement now begins at time t ₅ RB of the tool 2 that go back into a first reversing phase with the acceleration movement BB , which lies between the times t ₅ and t ₈ , and a second reversing phase, which lies between the times t ₈ and t _10, is subdivided. At time t ₁₀ , the workpiece surface is reached again and T (t ₁₀ ) = T (to), in the present example -2 mm.

In the in 15th and 16 The illustrated embodiments is, without loss of generality, the control of the feed movement VB and the reversing movement RB essentially symmetrical to the reversal point UP designed, ie the graphs for the depth of penetration T = T (t) are essentially axis-symmetrical or mirror-symmetrical to a point through time t _{5 of} the reversal point UP running perpendicular axis of symmetry and the graphs of the speeds nw (t) and n _s (t) are each essentially point-symmetrical to the point (t ₅ , 0) at the reversal point UP .

It was in the embodiments of 15th and 16 the dependency or synchronization of the depth of penetration T = T (cp) of or with the angle of rotation φ with varying thread pitch parameters in the undercut movement FROM according to 12th and 13th and 14th elected.

How to get into the 15th and 16 can immediately recognize, the real temporal progressions of the speed n _w (t) differ considerably despite the theoretically same resultant maximum speed nmax on the tool, here 4,500 rpm, programmed in the machine control. This is explained in more detail below.

In the embodiment according to the invention with translation unit according to 15th the machine control increases the speed n _w (t) according to the specified maximum rotational acceleration from the point in time at T = 0 mm and reaches _{the maximum value n s.max of} the speed of the machine _{spindle and the corresponding gear ratio shortly before time t 0} at the entry point EP maximum value of the speed of the tool. This maximum value of the speed of the tool now reaches or corresponds to the theoretical, programmed maximum speed nmax of the tool, here the full 4,500 rpm, corresponding to n _s.max = I nmax = 1,020 rpm for the spindle.

This maximum speed nmax is now kept constant over a plateau with a time interval Δt ₁ between times to and t ₁ , ie nw (t) = nmax or correspondingly n _S (t) = n _{S, max} in the time interval between t ₀ and t _{1 of} the interval length Δt ₁ .

At time t ₄ , the speed n _w (t) decreases again down to a local minimum at a minimum _{speed n min} , that or those already within the braking movement FROM , that is here shortly after time t ₂ .

The speed difference between maximum speed nmax and minimum speed n _min is denoted by Δn, i.e. Δn = nmax - nmin and should not exceed 0.8 nmax. Δn depends on the machine and machine control used.

Now after reaching the minimum speed n _{min increases} as a result of the control of the undercut movement FROM the speed nw (t) immediately increases again and again reaches the maximum speed nmax for the second time at the point in time t ₃ , which is kept constant over a second plateau with a time interval Δt ₃ between the points in time t ₃ and t ₄ , ie nw ( t) = nmax or correspondingly n _S (t) = n _{S, max} in the time interval between t ₃ and t _{4 of} the interval length Δt ₃ .

With other values for the transmission ratio I, in particular in a value range from I = 3 to 8, and with other values for the maximum rotational speed nmax in particular in a value range from 3,000 to 10,000 rpm, the time profile of the speed nw (t) is, also in the different combinations, qualitatively the same. In particular, the two plateaus Δt ₁ and Δt _{3 also occur} with the intermediate time interval Δt ₂ .

The absolute values of the interval length of the second plateau Δt ₃ depend on the transmission ratio I and the maximum speed nmax and also on the machine control. In particular, the interval length Δt _{3 of} the second plateau can be selected in a range from 0.01 s to 0.25 s, in particular 0.02 s to 0.13 s.

From time t ₄ , the speed n _W (t) increases to 0 at the reversal point UP at time t ₅ .

The intermediate time interval Δt ₂ between the times t ₁ and t ₃ , which lies between the two plateaus, _{i.e. the periods Δt 1} and Δt ₃ with maximum speed nmax, is also machine-dependent and should generally not be avoidable, but should be possible be kept short.

The absolute values for the interval length of the intermediate time interval Δt ₂ for the various gear ratios I and maximum speeds nmax are, in particular, between 0.05 s and 0.15 s, preferably between 0.06 and 0.10 s, and therefore generally do not vary as strong as at Δt ₃ .

The ratio Δt ₂ / Δt _{3 of} the time interval Δt ₂ between the plateaus and the time interval of the second plateau Δt ₃ is also of interest here, because the time interval Δt _{2 of} the first plateau is also dependent on the thread length.

In general, the ratio Δt ₂ / Δt _{3 is} in a range from 0.3 to 3.4 for the various transmission ratios I and maximum speeds nmax, in particular in a range from 0.5 to 2.4.

This course of the speed n _W (t) during the working movement between times t ₁ and t _{5 is} repeated, as in FIG 15th can be seen in the reversing movement between times t ₅ and t ₁₀ mirrored at the point of reversal UP with two plateaus of maximum speed - nmax, namely the plateau Δt ₃ between times t ₆ and t ₇ and the plateau Δt ₁ between times t ₉ and t ₁₀ and the intermediate range of lower speed with the absolute _minimum speed - n min between the times t ₇ and t ₉ .

In the version without translation unit according to 16 the machine control increases the speed n _W (t) according to the specified maximum rotational acceleration from the point in time at T = 0 mm via the point in time t ₀ at the entry point EP to the point in time t ₁ , until a local and global maximum at this point in time t ₁ is reached, but without a plateau, ie without a time interval in which the speed remains at its maximum value. Rather, the maximum value of the speed nw (t) is left again immediately, ie the speed nw (t) immediately _{decreases again from the point in time t 1.} Furthermore, the maximum value of the speed nw (t) actually achieved is below the programmed maximum speed nmax.

At time t ₃ , the speed nw (t) reaches a local minimum n _min that already within the braking movement FROM , that is here shortly after time t ₂ . Now increases as a result of the control of the undercut movement FROM the speed nw (t) increases again and reaches a second local maximum at time t ₄ and only then increases to 0 at the reversal point UP at time t ₅ . The maximum at the point in time t ₄ is smaller than the maximum at the point in time t ₁ and is punctiform, ie no plateau with a constant speed is formed here either.

This course of the speed n _W (t) during the working movement between times t ₁ and t _{5 is} repeated in the reversing movement between times t ₅ and t _10, mirrored at the point of reversal UP with two absolute maximums at times t ₆ and t9 and an intermediate absolute minimum - n _min at time t ₈ . Even in the reversing movement, the absolute maximum speed - nmax is not reached and the desired speed plateaus do not occur.

The flank rises or slopes in the speed are limited or determined in both exemplary embodiments and generally by the maximum rotational acceleration of the machine spindle.

For versions with the translation unit as in 15th were compared to versions without a translation unit as in 16 Improvements in thread quality, machine wear, tool load and, as a result, probably also the tool life were noted.

An embodiment of a translation unit can be formed by modifying the speed synchro ^® by the applicant. In contrast to the known, a rigid coupling is implemented without length compensation by means of elastomers, in order to increase the accuracy of the vicinity of the reversal point UP not endanger the control steps carried out.

It has now been shown that with the braking or undercut movement FROM or circumferential groove generation according to the invention a cleaning of the remaining material residues such as chip root or form bead takes place before the tool movement is reversed at the reversal point and therefore no excessive stress occurs on the thread teeth during the reversing movement. As a result, breaks in thread teeth made of the brittle, hard materials can be avoided and thread generation areas or thread teeth, in particular on separately manufactured, replaceable thread generation elements made of hard metal or another similarly brittle material, can be used.

Thus, in or through the method according to the invention with the axial thread generating movement with the integrated braking or undercutting movement FROM or Circumferential groove generation can now be practically any axial thread generating tool, i.e. taps or thread forming tools or combinations thereof or other cutting and non-cutting axial thread generating tools, in particular those with thread teeth made of hard metal or another brittle material, in particular thread teeth on separate thread generating elements that are detachably attached to a support body or holder .

The thread generating tool can now in embodiments, such as in 17th to 22nd is shown, have a carrier body and a thread generation region with one or more thread teeth distributed over one or more thread generation element (s) that are detachably or exchangeably fastened to the carrier body.

In other embodiments, the threading tool, such as for example in FIG 23 to 26th is shown, be formed monolithically, wherein the thread generating area with one or more thread teeth on a base body is made in one piece with this, for example by machining such as grinding.

The carrier body or the base body can also have a neck, i.e. the diameter tapering or decreasing continuously or in steps towards the thread generation area.

17th shows a thread generating tool, in particular a tap, with three thread teeth 11, 12 and 13 at the corners of a plate-shaped thread generating element having a triangular basic shape 10 . The thread generating element 10 is outwardly by three flat side surfaces reproducing the triangular shape 14th limited, extending to the rear areas of the open spaces F1 to F3 the thread teeth 1 to 13 extend. The open spaces go in front F1 to F3 in thread cutting G1 to G3 of thread teeth 1 to 13 above. The thread cutting G1 to G3 lie on respective rake faces, which are each one on the respective thread tooth 11 to 13 adjacent and preferably axially or straight flute 15th are formed.

By means of a through a central opening in the thread generating element 10 axially guided central fastening screw 27 is the thread generating element 10 at the front on the face or face 22nd a carrier body 20th attached. The tool axis A. runs centrally through the carrier body 20th and the thread generating element 10 .

In the 18th to 21 is an exemplary embodiment of a thread-generating tool with several, here for example six, thread-generating elements that can be used multiple times due to multiple thread cutting 71 to 76 shown.

The thread generating elements 71 to 76 have four thread cutting edges in an approximately rectangular, symmetrical and plate-shaped basic shape G at the four corners with respective upstream rake faces.

Each of these thread generating elements 71 to 76 is in an associated receptacle 91 to 96 of the carrier body 20th at its end face 22nd inserted and by means of a through a central opening in the thread generating element 71 to 76 guided, not shown fastening screw detachable and exchangeable on the support body 20th attached. The receptacles 91 to 96 can match the thickness of the thread generating elements 71 to 76 be adapted so that the front surfaces of the thread generating elements 71 to 76 essentially flush with the face 22nd of the carrier body 20th to lock. By turning through 180 ° or turning the thread generating elements 71 to 76 are these four times. ie with one of the four threads G can be used like an indexable insert.

One thread bar each with two thread cutting edges G can forms a thread tooth GZ . The thread teeth GZ of the various thread generating elements 71 to 76 are again on a helix with the thread pitch P , preferably each axially around ΔP and in the circumferential direction by a pitch angle Δα equally spaced.

But there are also designs of thread generating elements 71 to 76 with only three or two or even just one thread cutting edge G possible and also with other than rectangular or plate-shaped basic shapes and also with a number other than 6.

The outermost radial distances of the active thread cutting G the thread teeth of the thread generating elements 71 to 76 are denoted by r1 to r6 and preferably increase in the opposite direction to the winding direction, i.e. r1 <r2, r2 <r3, ... to r5 <r6.

In 22nd is now a threading tool with a threading element 80 on one end face 22nd a carrier body 20th shown. The plate-shaped thread generating element, again designed as a working head 80 here has a star-shaped basic shape with, for example, eight thread teeth 81 to 88 around the center through the threading element 80 and the support body 20th running tool axis A. for example, are arranged equidistant and in front which again a rake face is formed by a flute.

By means of a through a central opening in the thread generating element 80 axially guided central fastening screw 27 is the thread generating element 80 at the front of the face 22nd of the carrier body 20th attached.

The thread generating element is in 17th as well as in 22nd designed as a front working head or threaded head with the complete thread generation area or all thread teeth. The carrier body 20th can therefore be designed very simply and, for example, as in 17th or 22nd shown, a body that is easy to manufacture with respect to the tool axis A. cylindrical shape or shaft shape, half the diameter of which is smaller than the radial distance of the thread teeth from the tool axis A. . On the outer surface of the carrier body 20th coolant and / or lubricant leakage can occur 26th be provided.

In other embodiments, as in 18th to 21 shown, a plurality of thread-generating elements, which are detachably fastened separately to the carrier body and are provided around the tool axis A. are distributed in the circumferential direction and arranged at a distance from one another. Each thread generating element can have an effective or working thread tooth or thread cutting edge, but also have additional non-active thread teeth or thread cutting as reserves, but which become active by turning and / or remounting the thread generating element on the carrier body. In addition to a detachable fastening, however, a permanent fastening of the thread generating element on the carrier body is also possible, for example by soldering or printing in 3D printing.

Additional form-fit connections, not shown, can also be used for additional protection against rotation or, if necessary, also axial protection at the connection point between the carrier body 20th and thread generating element, for example 10 according to 17th or 80 according to 22nd , be provided.

In the embodiment according to 23 to 26th a monolithically produced front region of a tap is shown, which is thus essentially formed from one material. In a base body, which has a cylindrical basic shape, several, for example five, are axially to the tool axis A. running separating grooves 25th several, in particular five, successive thread teeth Z1 to Z5 separated from one another, which run along the circumference around the tool axis A. are arranged and thread cutting in the direction of the winding G and behind it open spaces F. exhibit. Behind the thread generation area formed from the thread teeth Z1 to Z5, the cylindrical outer surface of the base body is denoted by 31.

In front of the thread generating area formed from the thread teeth Z1 to Z5, there is now also a cylindrical guide area 33 formed to guide the tool on the core hole wall in the core hole 36 . To the front 32 of the base body is the guide area 33 via a bevel on the face 34 over. In the front 32 can be a central outlet for coolants and / or lubricants.

The thread creation areas 4th and their thread teeth, especially 41 and 42 in 1 to 10 or 11 to 13th in 17th or the G at 71 to 76 in 18th to 21 or 81 to 88 in 22nd or Z1 to Z5 in 23 to 26th , are along the according to the thread to be generated 50 formed helix or helical line with the thread pitch P arranged one behind the other and at the corresponding pitch angle to one another and also engage in each point in the workpiece along the thread turn one after the other 50 on. The axial distance ΔP the thread teeth or their thread cutting is related to the pitch angles. With an even division, both the pitch angles and the axial distances are the same, with unequal division they are of different sizes.

Due to the undercut movement FROM at least the axial dimension of the thread depth is now lost due to the circumferential groove. The axial dimension of the circumferential groove becomes larger the longer the thread generation area extends along the tool axis A. extends. Therefore, in the tool and process according to the invention, it is advantageous to use the thread generation area 4th or to keep the axial distance between the first thread tooth and the last thread tooth opposite to the direction of the winding as small as possible, preferably in a range between 0.5 P and 1.5 P.

The thread teeth can all be designed to cut or all to form or also to cut or form in any order or configuration.

A cut or chamfer area or run-up in the thread generation area is preferred 4th educated. This means that the thread profile of the thread 50 is successively cut or shaped from the individual thread teeth to the complete thread profile. So there are the thread profiles of the individual thread teeth divided and result in the complete thread profile at the end.

For example, take the outer radial distances of the thread teeth from the tool axis A. opposite to the direction of the winding, so that the thread root of the thread turn 50 is incorporated more and more deeply. This is according to, for example, in the exemplary embodiments 18th to 21 and 23 to 26th visible. Due to the axially short thread generation area 4th This section or threading area preferably extends over the entire thread generation area and there is then no calibration or guide area with thread teeth of the same thread profile. This has the disadvantage that the tool is not guided as well in the core hole and the thread just created as a conventional tap.

The 27 to 30th show exemplary embodiments of a division of the thread action profiles, for example in the case of the tool 2 according to 1 to 10 or 17th to 26th . The thread profile is successively generated by superimposing individual active profiles of successive thread teeth, whether cutting or shaping. This is, in particular, a special design of a gate or chamfer area.

There are successively added thread tooth profile surfaces ΔAi as differential profiles of two successive thread tooth profiles, for example with five thread teeth ΔA1 to ΔA5 until finally the entire thread profile GP arises as a superimposed active profile.

In 27 the thread tooth profiles and the differential profiles or thread tooth profile surfaces ΔAi lie symmetrically in a trapezoidal or metric thread profile GP and increase in a geometric expansion in the form of increasing individual trapezoidal or metric thread tooth profiles, so that both the thread flanks and the thread root of each thread tooth are further incorporated.

In 28 the thread tooth profiles and the differential profiles or thread tooth profile surfaces ΔAi again lie symmetrically in a trapezoidal or metric thread profile GP , however, have the same pitch diameter and increase in height as the individual trapezoidal or metric thread tooth profiles become larger, so that only the thread root and the adjacent thread flank sections of each thread tooth are further incorporated.

In 27 the thread tooth profiles and the differential profiles or thread tooth profile surfaces ΔAi lie symmetrically in a trapezoidal or metric thread profile GP and increase in a geometric expansion in the form of increasing individual trapezoidal or metric thread tooth profiles, so that both the thread flanks and the thread root of each thread tooth are further incorporated.

In 28 First, larger triangular thread tooth profiles are used for the first four thread teeth, so that an asymmetrical triangular differential profile or thread tooth profile surface ΔA1 and correspondingly inclined strip-shaped differential profiles or thread tooth profile surfaces ΔA2 to ΔA4 arise. The final trapezoidal or metric thread profile GP is then completed by the last thread tooth according to the difference profile or thread tooth profile area ΔA5.

30th shows a special thread profile division for trapezoidal or metric thread profiles GP , in which two thread teeth with essentially the same size trapezoidal thread profile surfaces ΔA1 and ΔA2 on opposite thread flanks of the thread profile GP are used and then two increasingly larger trapezoidal thread profiles of the two subsequent thread teeth again on opposite thread flanks of the thread profile GP , so that the difference profiles or thread tooth profile surfaces ΔA3 and ΔA4 arise. The final trapezoidal or metric thread profile GP is then completed by the last thread tooth according to the difference profile or thread tooth profile area ΔA5.

Identical thread tooth profile surfaces, in particular ΔA1 = ΔA2 as, for example, in 30th usually mean equal volumes of the cut or shaped thread part profile of the thread 50 . Same thread tooth profile depths, especially as in 27 and 28 , usually mean the same chip thicknesses when cutting or indentation depths when forming the corresponding thread part profiles of the thread turn 50 .

In the case of differently designed and / or more or less than five thread teeth, the division can also be designed differently.

In all embodiments, preferably at least the thread teeth, the or each thread generation area or the thread generation elements, in monolithic embodiments also the entire tool, are made of hard metal such as a hard metal alloy, in particular P steel or K steel or cermet, or cemented hard metal, in particular tungsten carbide, optionally alloyed or mixed with metals or other metal carbides, or titanium nitride or titanium carbide or titanium carbonitride or aluminum oxide, or cutting ceramics, especially polycrystalline boron nitride (PKB), or polycrystalline diamond (PKD). Due to the undercut movement, the durability and service life of these rather brittle materials is significantly increased.

Alternatively, high-speed steel such as high-speed steel (HSS steel) or cobalt-alloyed high-speed steel (HSS-E steel) can also be used.

The carrier body to which the thread generating element is attached can be made of any material, but preferably a material that is easier to manufacture, such as high-strength steel. In principle, it is also possible that the carrier body is made of high-speed steel such as high-speed steel (HSS steel) or cobalt-alloyed high-speed steel (HSS-E steel) or also of hard metal such as a hard metal alloy, in particular P steel or K steel or cermet, or sintered carbide , in particular tungsten carbide, optionally alloyed or mixed with metals or other metal carbides, or titanium nitride or titanium carbide or titanium carbonitride or aluminum oxide, or cutting ceramics, in particular polycrystalline boron nitride (PCB), or polycrystalline diamond (PCD) is formed or manufactured.

Furthermore, additional coatings, in particular wear protection layers, can be applied to the tool, in particular its thread generation area or at least its thread teeth.

The carrier body preferably has an internal coolant and / or lubricant supply and thus internal channels. The carrier body can be produced in various ways, including by 3D printing and / or machining.

In one embodiment, preferably in the front area or as the front thread tooth, a thread tooth is provided which has a thread tooth profile with a front thread tooth profile flank and a rear thread tooth profile flank as well as a front flank flank flank directly adjoining the front thread tooth profile flank on a front thread tooth flank and one directly adjacent to the rear one Has thread tooth profile flank subsequent rear flank flank on a rear thread tooth flank. The front flank clearance surface is exposed to the rear or set back with respect to a front thread tooth flank envelope which runs along or parallel to the helical line and through the front thread tooth profile flank. It is now the rear flank clearance surface opposite a rear transverse plane, which is directed perpendicular to the tool axis and runs through the rearmost point of the thread tooth profile or the rear thread tooth profile flank, offset to the front or exposed. The helical line is inclined backwards by the thread pitch angle with respect to the rear transverse plane. This exposure of the thread tooth prevents or at least greatly reduces friction of the thread tooth on the workpiece surface both on its front thread tooth flank and on its rear thread tooth flank both during the working movement and during the braking movement. Here and in the following, “front” or “front” are to be understood as following in the direction of the forward movement or the direction of winding of the thread generation area and “rear” or “rear” as in the opposite direction, i.e. opposite to the direction of the forward movement or in the direction of the backward movement or opposite to the direction of the winding of the thread generation area.

In embodiments, the front flank clearance surface is inclined or set back with respect to the front thread tooth flank envelope by a front flank clearance angle which is generally in an interval between 0 ° and 10 °, in particular between 0 ° and 2 °. In advantageous embodiments, the rear flank flank face is inclined or set back with respect to the rear transverse plane by an angle which is generally in an interval between 0 ° and 6 °, in particular between 2 ° and 5 °, and / or with respect to a rear thread tooth flank envelope that extends along which extends or runs parallel to the helix, is inclined or set back by a rear flank clearance angle which is greater than the thread pitch angle and generally in an interval between the thread pitch angle and 6 °, in particular between 4 ° and 5 °. The flank free surfaces can run helically, i.e. linearly in the development, or also assume (differently) curved shapes, in particular tapering even more towards one another at least in sections or also tapering less strongly towards one another. In such an embodiment, the corresponding flank clearance angle can define a boundary line or surface which is not exceeded (outwards) by the flank clearance area.

In a further embodiment, the thread generation area, in particular in its rear area or as the rearmost thread tooth, has at least one thread and reaming tooth. This thread and reaming tooth has a thread tooth element with a thread tooth profile as an active profile for generating or reworking the thread in a front-side area, viewed in the direction of the winding. Furthermore, the thread and reaming tooth has a reaming element for reaming the generated thread during a reversing movement in a rear region, viewed in the direction of the winding on, wherein the clearing element has a clearing profile as an active profile, which preferably corresponds to the thread profile of the generated thread and / or corresponds to the thread tooth profile on its front area.

The clearing element preferably has a clearing blade which has a clearing profile that corresponds to the thread tooth profile of the threaded tooth element, in particular has an active profile that is the same or at least the same on the clearing profile flanks of the clearing profile as the thread tooth profile. Furthermore, in an advantageous embodiment, the clearing element has a furrowing clearing surface which is arranged downstream of the clearing edge when viewed opposite to the direction of winding, the active profiles of the clearing edge and the clearing surface superimposing one another to form the entire clearing profile of the clearing element. The clearing surface preferably rises radially outward in the direction of the winding and can merge into a toothed web, which in particular has a constant profile or no free surfaces, wherein in particular a clearing profile head of the clearing surface and / or the toothed web is smaller than a clearing profile head of the reaming edge. The tooth flanks of the thread and reaming tooth can run at least predominantly or completely along associated front thread tooth flank envelopes or rear thread tooth flank envelopes or without free areas.

In a particularly advantageous embodiment of the tool, the thread generation area has both at least one thread tooth as described and at least one thread and reaming tooth, the thread and reaming tooth being the last tooth of the thread generation area in the direction of the winding and thus the first tooth in the reversing movement.

In a further embodiment, at least one thread tooth or the thread and reaming tooth has a thread cutting edge in its front area in the direction of the winding or in the thread tooth element and preferably also a thread cutting surface downstream of the thread cutting edge in the direction of the winding for generating a surface with good surface quality, the active profiles of the Overlay the thread cutting edge and the thread forming surface to form the thread tooth profile, preferably corresponding to the thread profile, on the front-side area. The thread-forming surface can rise radially outwards in the opposite direction to the direction of the winding and preferably merge into or into the toothed web, which in particular serves as a calibration area and / or has a constant profile or no free surfaces. A thread tooth profile head of the thread groove surface and / or the tooth web can now be smaller than the thread tooth profile head of the thread cutting edge.

• Führungsgewinde kann nicht mehr ausbrechen
  • - Statt Spannuten kann ein Hals geschliffen werden, der die Späne nicht behindert
  • - Durch kleinen Führungs-/Dichtzylinder kann das Werkzeug für Sacklochbearbeitung mit IKZ so eingestellt werden, dass der Kühlmittelstrahl direkt auf die Schneide oder auf den Span gelenkt wird
  • - Dadurch eventuell sehr tiefe Sacklochbohrungen möglich
  • - Sehr kurzer Gewindeauslauf analog Gewindefräsen mit einschraubbarem Freistich (Hydraulik!)
  • - Kein Umkehrschnitt! Spanwurzeln werden im Freischneidprozess entfernt
  • - konstante Schnittgeschwindigkeit (analog Drehprozess) mit Speedsynchro®
  • - Variable Anschnittaufteilung (-gestaltung), beispielsweise Anstrehlung, Anschnittwinkel auch nach hinten, Radius am Außen, am Vollzahn eine Art Verbreiterung. Bevorzugt Anstrehlung kombiniert mit zylindrischem Anschnitt
  • - Freiheitsgrade in der Gestaltung des Schneidkeils (z.B. Spanwinkel, Spanleitstufe, Schräge, Drall, Negativfase, Freiwinkel)
  • - Gezielte Schneidkantenpräparation
  • - Günstige Komplettbearbeitung auf CNC (monolithische GB)
  • - Schneidplatten führen zu niedrigen Tool Cost per Hole bei großen Serien
  • - Bei Schneidplatten: Einstellbare Platten für unterschiedliche Toleranzen
  • - Schneidende und / oder Formende Gewindeanteile oder Kernschneidanteile möglich
• Anzahl der Gewindezähne:
  • - Mindestens ein Gewindeschneidzahn, maximal mehrere Gewindeschneidzähne und mehrere Nuten, über maximal 3 Gewindegänge axial angeordnet
  • - Bevorzugt etwa über 0,5 -1,5 x Gewindesteigung axial angeordnet
  • - Bevorzugt über einen Gewindegang axial angeordnet
  • - Ungleiche Teilung bei der Anordnung der Zähne am Umfang
  • - Teilweise oder ganz additiv hergestellt, beschichtet, unbeschichtet, oberflächenbehandelt
• Bei Schneidplatten allgemein:
  • - Einstellbare Platten für verschiedene Toleranzen
  • - Verschiedene Schneidplattengeometrien, z.B. Schmetterlingsplatten oder Standardplatten (ISO), dreieckig, viereckig, rhombisch, etc.
• Dreiecksplatte:
  • - Schneidkopf mit mehreren Schneiden

A few characteristic advantages and features of the invention are given here once again in key words:

• Guide thread can no longer break out
  • - Instead of flutes, a neck can be ground that does not obstruct the chips
  • - With the help of a small guide / sealing cylinder, the tool for blind hole machining with ICZ can be set so that the coolant jet is directed directly onto the cutting edge or onto the chip
  • - This means that very deep blind holes may be possible
  • - Very short thread runout analogous to thread milling with screw-in undercut (hydraulic!)
  • - No reverse cut! Chip roots are removed in the free cutting process
  • - Constant cutting speed (analogous to the turning process) with Speedsynchro®
  • - Variable gate division (design), for example stratification, gate angle also to the rear, radius on the outside, a kind of widening on the full tooth. Preferably spotlighting combined with a cylindrical gate
  • - Degrees of freedom in the design of the cutting wedge (e.g. rake angle, chip breaker, bevel, twist, negative bevel, clearance angle)
  • - Targeted cutting edge preparation
  • - Cheap complete machining on CNC (monolithic GB)
  • - Inserts lead to a low tool cost per hole for large series
  • - For cutting inserts: adjustable inserts for different tolerances
  • - Cutting and / or shaping thread portions or core cutting portions possible
• Number of thread teeth:
  • - At least one thread cutting tooth, a maximum of several thread cutting teeth and several grooves, arranged axially over a maximum of 3 thread turns
  • - Preferably arranged axially about 0.5-1.5 x thread pitch
  • - Preferably arranged axially via a thread
  • - Unequal pitch in the arrangement of the teeth on the circumference
  • - Partly or entirely additively manufactured, coated, uncoated, surface treated
• For cutting inserts in general:
  • - Adjustable plates for different tolerances
  • - Different insert geometries, e.g. butterfly inserts or standard inserts (ISO), triangular, square, rhombic, etc.
• Triangle plate:
  • - Cutting head with several cutting edges

List of reference symbols

2

Tool

4th

Thread creation area

5

thread

6th

workpiece

10

Thread generating element

11 to 13

Thread tooth

14th

Side face

15th

Spannut

20th

Carrier body

21

shaft

22nd

Front side

25th

Separating groove

26th

Coolant and / or lubricant leak

27

Fastening screw

30th

Base body

31

Outer surface

32

Face

33

Guide surface

34

Bevel

35

Core hole

36

Threaded hole

40, 41

Thread tooth

50

Thread

51, 52

Circumferential groove

53

Core hole bottom

55

Thread profile

60

Workpiece surface

71 to 76

Thread generating element

80

Thread generating element

81 to 88

Thread tooth

a

Groove length

A.

Tool axis

FROM

Deceleration movement

b

Thread gap

BB

Acceleration movement

c

Thread profile width

d

Core hole diameter

D.

Thread hole diameter

F.

Open space

F1 to F3

Open space

G

Thread cutting

G1 to G3

Thread cutting

GP

Thread profile

GZ

Thread tooth

M.

Thread center axis

P

Thread

P ₁ to P ₁₀

Slope parameters

RB

Backward movement

ΔA1 to ΔA5

Thread tooth profile effective surface

S ₁ to S ₁₀

Deceleration step

S ₁₁ to S ₂₀

Acceleration step

T

End ring depth

T _G

Thread depth

T _L

Thread hole depth

T ₀ to T ₁₀

Depth value

T _i , T _n

Depth value

ΔT

Penetration depth range

UP

Turning point

VB

Forward movement

W.

Twist sense

Z

Thread tooth

ΔP

pitch

Δα

Pitch angle

δ

Thread pitch angle

ε

Opening angle

φ

Total angle of rotation

Δφ

Rotation angle range

φ ₀ to φ ₂₀

Angle of rotation value

φ _i , φ _n

Angle of rotation value

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 2229257 B1 [0014, 0021]
• DE 102016008478 A1 [0015, 0021]

Claims (34)

Method for generating a thread with a predetermined thread pitch in a prefabricated core hole in a workpiece, a) where a tool is used to create a thread, a1) wherein the tool is rotatable about a tool axis (A) running through the tool and can be moved axially to the tool axis, a2) wherein the tool comprises at least one thread generation area (4) which runs with a predetermined thread pitch (P) and a predetermined direction of winding (W) of the thread (50) to be generated around a tool axis (A) running through the tool and has an active profile which corresponds to the thread profile of the thread to be generated, a3) each thread generation area having one or more thread teeth, b) in which the tool is moved into the prefabricated core hole in the workpiece in a work movement during a first work phase, b1) wherein the working movement comprises a rotary movement with a predetermined direction of rotation about the tool axis (A) of the tool and an axial feed movement of the tool in an axial forward direction (VB) axially to the tool axis, synchronized with the rotary movement according to the thread pitch of the thread generating area, such that a full rotation of the tool around the tool axis corresponds to an axial feed of the tool by the specified thread pitch, b2) wherein the thread generating area generates a thread (50) in the wall of the core hole (36) running at the predetermined thread pitch during the first work phase in the work movement, c) the tool being moved further into the workpiece up to a reversal point (UP) in a braking movement (AB) during a second work phase following the first work phase, c1) wherein the axial advance of the tool, based on a full revolution, is at least during part of the braking movement, preferably during the entire braking movement, smaller in amount than the thread pitch and is zero at the reversal point and c2) the thread generating area, in particular the thread tooth or teeth, of the tool generating at least one, in particular closed or annular, circumferential groove (51, 52) in the wall of the core hole (36) in the workpiece during the braking movement. Procedure according to Claim 1 In which a) the tool has a carrier body (20) through which the tool axis runs, and at least one thread generating element, in particular produced separately from the carrier body, which is fastened to the carrier body, in particular is fastened interchangeably or detachably, b) each thread generating element has at least one thread generation area. Procedure according to Claim 1 or Claim 2 , in which the or each thread generating area is arranged on a front end area of the tool and / or in which the or each thread generating element is attached to a front end area of the support body, preferably on an end face (22) of the support body. Procedure according to Claim 2 or Claim 3 , in which the thread generating element is designed as a frontal threaded head with the complete thread generating area or all thread teeth, the tool axis running centrally through the carrier body and the thread generating element, the thread generating element in particular by means of a central fastening screw (27) at the front, which is axially guided through a central opening in the thread generating element is attached to the end face of the carrier body, Procedure according to Claim 4 , in which the thread generating element has a triangular basic shape with three thread teeth (11, 12 and 13) with thread cutting (G) and free surfaces (F) at the corners and / or is plate-shaped and / or outwards by three flat side surfaces reproducing the triangular shape (14), which in particular extend as far as the rear areas of free surfaces (F1 to F3) of the thread teeth, and / or has flutes (15) adjoining the respective thread teeth (11 to 13) and preferably axially extending. Procedure according to Claim 4 , in which the thread generating element (80) has a star-shaped basic shape and / or is plate-shaped and / or has several, in particular eight, thread teeth which are arranged around the tool axis and in front of which a flute is formed. Procedure according to Claim 2 or Claim 3 , in which several thread generating elements are attached separately to the carrier body and are distributed around the tool axis A in the circumferential direction and are arranged at a distance from one another. Procedure according to Claim 7 , in which the or each thread generating element has a working active thread tooth or a working active thread cutting edge and additionally has at least one, in particular one, two or three, further inactive thread tooth or thread cutting edge, which turns by releasing the releasable fastening and / or rotating the Thread generating element and reattaching to the carrier body to one or an active working thread tooth or thread cutting edge. Procedure according to Claim 8 , in which the or each thread generating element in an approximately rectangular or triangular symmetrical and plate-shaped basic shape has four or three thread cutting (G) at the four or three corners with respective upstream rake faces. Method according to one of the Claims 7 to 9 , in which the or each thread generating element (71 to 76) is inserted in an associated receptacle (91 to 96) of the carrier body (20), in particular on its end face (22), and in particular by means of a fastening screw guided through a central opening in the thread generating element is detachably and exchangeably attached to the carrier body, the recordings preferably being adapted to the thickness of the thread generating elements so that the front surfaces of the thread generating elements are essentially flush with the end face (22) of the carrier body. Method according to one of the Claims 2 to 10 , in which the carrier body has a cylindrical shape with respect to the tool axis A at least in the area of the thread generating element, in particular has a cylindrical neck, and / or in which the carrier body is at least partially made of a steel, in particular high-strength steel. Procedure according to Claim 1 , in which the tool has thread generating areas formed monolithically on a base body through which the tool axis runs. Procedure according to Claim 12 , in which in the base body, which in particular has a cylindrical basic shape, several, in particular five, successive thread teeth (Z1 to Z5) are separated from one another by several, for example five, preferably axially to the tool axis running, separating grooves, which are separated from one another by the Tool axis are arranged and thread cutting in the direction of the winding and have free surfaces behind it, with a cylindrical outer surface of the base body being formed in particular axially behind the thread generating area formed from the thread teeth. Procedure according to Claim 12 or 13th , in which a cylindrical guide area (33) is formed in front of the thread generating area for guiding the tool on the core hole wall in the core hole (36), wherein in particular the guide area merges with an end face (32) of the base body via an end bevel and / or n the Front side is a central outlet for coolants and / or lubricants. Method according to one of the preceding claims, in which the or each thread generating area in the axial direction to the tool axis has an axial extension from a range between 0.5 P and 1.5 P of the thread pitch P or in which the axial distance to the tool axis between the opposite to the Winding sense of the first thread tooth and last thread tooth of the thread generating area from a range between 0.5 P and 1.5 P of the thread pitch P is selected. Method according to one of the preceding claims, in which the thread profile of the thread turn is successively cut and / or formed from the individual thread teeth up to the complete thread profile and / or in which the thread action profiles of the individual thread teeth are divided and at the end result in the complete thread profile. Method according to one of the preceding claims, in which the material for the thread teeth and / or the or each thread generation area and / or the thread generation elements and / or the carrier body and / or the base body and / or the entire tool is hard metal such as a hard metal alloy, in particular P -Steel or K steel or cermet, or cemented carbide, in particular tungsten carbide, optionally alloyed or mixed with metals or other metal carbides, or titanium nitride or titanium carbide or titanium carbonitride or aluminum oxide, or cutting ceramics, especially polycrystalline boron nitride (PKB), or polycrystalline diamond (PKD) is provided. Method according to one of the preceding claims, in which a) during the working movement, the speed of the rotational movement of the tool in its temporal course passes through a first plateau at which the speed remains constant at a predetermined maximum speed (nmax) and b) during the braking movement, the actual speed of the rotary movement of the tool runs through a second plateau over time, at which the speed remains constant at the same predetermined maximum speed (nmax), c) where the specified maximum speed of the rotary movement of the tool is selected to be at least so high that a path speed at the thread generation area of at least 57 m / min, in particular of at least 85 m / min, is achieved, which is a maximum speed with a thread diameter of 6 mm of at least 3000 rpm, in particular at least 4,500 rpm. Procedure according to Claim 18 , in which between the time interval (Δt ₁ ) of the first plateau and the time interval (Δt ₃ ) of the second plateau there is an intermediate _{time interval (Δt 2} ) in which the speed drops below the maximum speed, the ratio (Δt ₂ / Δt ₃ ) the interval length of the intermediate _{time interval (Δt 2} ) to the interval length of the time interval (Δt ₃ ) of the second plateau is in a range from 0.5 to 2.2, preferably 0.7 to 1.6. Procedure according to Claim 18 or Claim 19 , at which the maximum speed is already reached at the beginning of the first work phase or the work movement or at the point where the tool enters the workpiece. Method according to one of the preceding claims, in which a) the tool is driven by a machine drive in the working movement and in the braking movement and a transmission unit for the rotary movement, in particular a transmission gear unit, is connected (or coupled) with a predefined or predefinable transmission ratio between the machine drive and the tool, b) where the transmission ratio corresponds to the quotient of the speed of the machine drive and the speed of the tool and is a maximum of 1: 3, so that the tool rotates at least three times as fast as the machine drive, c) whereby in the programming of the machine drive a maximum speed of the rotary movement of the machine drive is programmed, which corresponds to the product of the transmission ratio and the specified maximum speed of the rotary movement on the tool. Procedure according to Claim 21 , in which the transmission ratio between 1: 3 and 1: 8 and preferably between 1: 4 and 1: 5 is selected. Method according to one of the preceding claims, in which during at least a predominant part of the second work phase or during the entire second work phase, the tool is moved in the same forward direction as during the work movement in the first work phase and / or where the braking movement is a rotary movement with a constant direction of rotation such as includes during the work movement. Method according to one of the preceding claims, wherein the rotational speed of the rotational movement at the reversal point is zero and / or in which the total or total axial feed of the tool during the braking movement is selected between 0.1 times to 2 times the thread pitch. Method according to one of the preceding claims, wherein during the braking movement the axial feed movement is controlled depending on the angle of rotation of the rotational movement of the tool according to a previously stored unique relationship, in particular a function or a sequence of functions, between the axial feed of the tool and the angle of rotation and Method according to one of the preceding claims, in which different relationships, in particular functions, between the axial advance of the tool and the angle of rotation are selected or set during the braking movement in several successive braking steps. Procedure according to Claim 26 , in which a linear function of the angle of rotation is selected for the axial penetration depth or the axial advance during several braking steps and / or in which the slope, i.e. the derivation of the axial penetration depth or the axial advance according to the angle of rotation, is constant and absolute in each of these braking steps is set to decrease from one deceleration step to a subsequent deceleration step. Procedure according to Claim 27 , in which an NC control for a thread process, for example a G33 path condition, with the thread pitch of the thread is used for the working movement and in the several braking steps also one, preferably the same, NC control for a thread process, for example a G33 path condition, with the respective constant pitch is used as the thread pitch parameter. Method according to one of the Claims 26 to 28 , in which, during several braking steps, the axial penetration depth or the axial advance is a particularly cubic spline function of the angle of rotation. Method according to one of the Claims 11 to 14th , in which the different functions of successive braking steps are set continuously and, in the case of differentiable functions, preferably continuously differentiable. Method according to one of the preceding claims, in which, in particular during an equalization step, the axial advance during the braking movement is zero in a rotation angle sub-interval and / or in a rotation angle sub-interval in the reverse direction opposite to the forward direction of the working movement. Method according to one of the preceding claims, in which the after reaching the Reversing point, a reversing movement of the tool is initiated, with which the tool is moved out of the workpiece, the reversing movement initially a first reversing phase, with which the thread generating area of the tool is guided back into the thread of the generated thread, and then a second reversing phase, during which the thread generating area is led out of the workpiece through the thread turn. Procedure according to Claim 32 , in which the reversing movement is carried out with a movement path that is symmetrical to the working movement and braking movement, with reversed direction of rotation and reversed feed. Procedure according to Claim 32 or Claim 33 , in which the reversing movement in the first reversing phase of the same absolute value, inverted only in the direction of rotation and advance direction, is stored in advance, in particular a function or a sequence of functions, between the axial advance of the tool and the angle of rotation is controlled as in the braking movement during a second work phase, possibly omitting or shortening the equalization step, if available.

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