EP2046528B1 - Method of grinding an indexable insert and grinding wheel for carrying out the grinding method - Google Patents

Description

1. a) die Wendeschneidplatte ist um eine senkrecht zu ihrer Ebene verlaufenden Drehachse zur Rotation angetrieben;
2. b) eine die Schleifscheibe lagernde und antreibende Schleifspindel sowie die Drehachse der Wendeschneidplatte werden in zwei senkrecht zueinander verlaufenden Verschiebeachsen relativ zueinander verschoben, wobei die Verschiebeachsen in parallelen oder identischen Ebenen liegen;
3. c) die Schleifspindel und die Wendeschneidplatte werden relativ zueinander um eine Schwenkachse verschwenkt, die senkrecht zu den Ebenen steht, in der die Verschiebeachsen und die Drehachse der Wendeschneidplatte liegen,

gemäß den Oberbegriffen der Ansprüche 1 bis 3.The invention relates to a method for grinding an indexable insert, in which the narrow sides thereof are moved along the circular contoured peripheral surface of a rotating grinding surface and ground by the latter, with the following CNC-controlled coordinated movements of the grinding process:

1. a) the indexable insert is driven for rotation about a plane perpendicular to its plane of rotation;
2. b) a grinding spindle supporting and driving grinding spindle and the axis of rotation of the insert are displaced in two mutually perpendicular displacement axes relative to each other, wherein the displacement axes are in parallel or identical planes;
3. c) the grinding spindle and the indexable insert are pivoted relative to one another about a pivot axis which is perpendicular to the planes in which the displacement axes and the axis of rotation of the indexable insert lie,

according to the preambles of claims 1 to 3.

Such a grinding method is known from DE 42 40 053 A1 known. The narrow sides of the indexable insert are ground in this known method with a narrow grinding wheel, which has a cylindrical peripheral contour. The grinding wheel is driven by a grinding spindle, which is displaceable in two mutually perpendicular horizontal planes. The indexable insert is located in a clamping device which is pivotable about a vertical axis. The clamping device has two Einspannstempel, which clamp the indexable insert on their broad sides between them and drive for rotation. By the clamping device around the vertical pivot axis is pivoted, a desired clearance angle can be sanded on the narrow sides of the turning cutting plates. During the grinding process, the following four movements are constantly coordinated with each other in a CNC-controlled manner: The rotational movement of the indexable insert about its driven axis of rotation (C-axis), the movement of the grinding spindle in the direction of the first displacement axis (Z-axis) and the second displacement axis (X-axis ) and the pivoting movement of the clamping device about the vertical pivot axis (B-axis). In this way it is possible to grind flat narrow sides with the desired clearance angle to the reversible cutting plate.

In the known method, the cylindrical grinding wheel is guided in the operation of the peripheral grinding with radial feed over the side surface of the indexable insert. It contacts the side surface in a straight line parallel to the grinding wheel axis of rotation. A line contact always means a higher heat load for the workpiece.

With the known method according to the DE 42 40 053 A1 should be improved by then usual grinding methods in which the narrow sides of the insert are ground with cup-shaped grinding wheels. However, there were difficulties in realizing the grinding process with four CNC interpolating motion axes. Therefore, in the known method according to the DE 42 40 053 A1 also expressly stipulated that during the grinding of the narrow sides of the cylindrically contoured narrow grinding wheel in the axial direction superimposed for controlled movement reciprocating reciprocated, whereby the engagement of the individual abrasive grains of the grinding wheel is to be constantly corrected. For this reason alone, the axial width of the grinding wheel must be greater than the thickness of the indexable insert. The grinding wheel must therefore have an unnecessarily large width, which is disadvantageous due to the then higher weight in mass production. Further, a large axial extent of the grinding wheel limits the processing capabilities that can be performed on the indexable insert. Moreover, in practice it has been shown that the grinding results did not lead to the hoped-for improvement. Excessively high grinding wheel wear and unsatisfactory precision in the grinding result, ie in the nature of the ground narrow sides, were found.

Presumably therefore, even after the announcement of the proposal in accordance with the DE 42 40 053 A1 have made further suggestions for grinding with cup-shaped inserts, such. B. the DE 43 01 214 A1 shows. Although this may have improved the grinding result again, but provided for this purpose pot-shaped grinding wheels were particularly complicated, namely constructed in several parts. As chamfers often have to be sanded during the grinding of indexable inserts, at least two abrasive linings of cylindrical shape were required, which lie in different planes. With one, deeper abrasive coating, the narrow sides of the indexable insert were ground, while the required chamfers should be ground with the second, in another axial plane abrasive coating. The grinding with cup-shaped grinding wheels also causes difficulties in terms of mutual accessibility of the surfaces to be ground on the indexable insert. Therefore, the improved methods of grinding indexable inserts with cup-shaped grinding wheels could not be economically satisfactory.

In a simple device for regrinding worn indexable inserts according to the DE 295 14 702 U1 It is known to regrind the indexable inserts with a grinding wheel, which has the profile of a double cone in cross section. The device is placed on the grinding of indexable inserts whose broad sides have a diamond-shaped contour. The indexable inserts are mounted on a tool carrier. Grinding wheel and tool carrier are relatively movable in two horizontal directions and the vertical. By raising or lowering the grinding wheels, a hollow grinding on the indexable insert or a clearance angle can be formed. The contour of the grinding wheel in the form of a double cone serves to grind different narrow sides of the indexable insert successively on one or the other conical surface of the grinding wheel. For this purpose, the clamped indexable insert must be pivoted only on the tool carrier, wherein at least one linear contact exists. This type of grinding is not comparable to a grinding operation that is economically carried out in the production of indexable inserts in mass production.

The DE 88 04 567 U1 deals with the so-called deep grinding of cylindrical workpieces. In this case, a rotating grinding wheel is guided by a cylindrical contour with considerable grinding depth along the workpiece circumference and parallel to its longitudinal axis. The axis of rotation of the grinding wheel can be made slightly inclined parallel to the workpiece longitudinal axis or opposite to this according to the so-called Quickpoint principle. The largest part of the material removal from the cylindrical outer wall of the workpiece is performed by the in the feed direction forward outer edge of the grinding wheel, and especially with the outer annular zone of the grinding wheel side surface. In this front area of the grinding wheel, therefore, the abrasive coating has a rough grinding wheel specification. The rear area adjoining the front area of the grinding wheel has a finer specification grinding surface; he should improve when driving over the cylindrical workpiece, especially its surface.

Of the DE 88 04 567 U1 there is no indication that a particular dimensional stability of the workpiece is desirable. Rather, the grinding wheel proposed there is used especially for roughing. The direction of the DE 88 04 567 U1 goes to the fact that the front in the feed direction edge region of the grinding wheel end face is not rounded off by wear, so that forms a so-called roof profile. In the Fig. 3 of the DE 88 04 567 U1 is such, caused by wear disadvantageous roof profile specially shown. It is that the front outer edge of the grinding wheel is rounded, the rounding passes through both areas of the abrasive coating. With the according to the DE 88 04 567 U1 The proposed modified grinding wheel specification is intended to prevent a rounded contour of the grinding wheel and to ensure that the desirable, strictly cylindrical contour of the grinding wheel is maintained as long as possible during the grinding operation.

The invention is based on the object to provide a grinding method of the initially mentioned type, with the inserts are produced in an economic mass production, in which the narrow sides even with the use of difficult to machine sintered sintered last have a perfect condition and the desired dimensional , Form and position tolerances are met.

A first solution of this object is achieved with the entirety of the features of claim 1. Here, a grinding wheel is used, which has a forwardly tapered lead area and an adjoining cylindrical caster area. The grinding process is carried out in such a way that the lead-in area, which forms a lead angle with respect to the contour of the indexable insert, performs a longitudinal grinding on the principle of peel-grinding, thereby first passing over the narrow side of the indexable insert. The lead-in area causes pre-grinding, for example roughing. The lead-in area removes most of the grinding allowance. By the lead-in area at the point of its largest diameter merges into the cylindrical trailing area, also an immediate transition from pre-grinding becomes performed on the regrinding on the surface of the narrow sides. The two processes can thus take place simultaneously.

It has been found that in the procedure according to the invention very good grinding results in conjunction with a significantly improved life of the grinding wheels are achieved, d. H. the wear of the grinding wheels is significantly reduced. This is due to the fact that during peeling grinding with a grinding wheel tapering forwards in the longitudinal direction of the grinding process, substantially improved cooling conditions exist, whereby the grinding wheel is spared and a minimum of heat is introduced into the workpiece in the grinding zone. The subsequent trailing area is significantly shorter than the flow area, z. B. amount to only one third of the grinding wheel thickness. When grinding by means of the trailing area, a line contact of the grinding wheel with the narrow side of the indexable insert, because the grinding wheel is perpendicular to the respective narrow side of the indexable insert. However, only relatively little material is removed here, and the contact length is short. Thus, the thermal stress of the grinding wheel and the workpiece is kept low here as well. The significantly reduced thermal load on the grinding wheel has proved to be decisive in the grinding of hard-to-machine carbide sintered materials of the indexable inserts. The service life of the grinding wheel could be significantly increased. In addition, cutting inserts made of ceramic materials can be processed with the grinding process.

A second solution of the object underlying the invention is achieved by the entirety of the features of claim 2. The Applicant has found that a slight pivoting of the grinding wheel relative to the indexable insert can lead to similar good results as the orientation perpendicular to the respective contour of the narrow side during grinding according to the first solution. When proceeding according to claim 2, the grinding wheel forms a leading angle in the lead-in area and in the trailing area a clearance angle with respect to the narrow side of the indexable insert to be ground. This is also possible if the trailing region of the grinding wheel is cylindrically contoured as in the procedure according to claim 1. The grinding wheel is then abrasive only with the tapered feed area up to the largest grinding wheel diameter. Clearly lead angle and clearance angle lead to a further improvement of the cooling conditions. The method according to claim 2 can also be done by peel grinding. For very hard sintered materials u u. U. perform the pre and regrinding with two different grinding wheels. If, however, the trailing region is likewise tapered starting from the largest diameter of the grinding wheel, a larger starting angle and a larger clearance angle result, without the grinding wheel having to be tilted or pivoted particularly strongly in relation to the indexable insert.

A third solution of the problem underlying the invention is set forth in claim 3. The applicant has found that the trailing area can even be completely eliminated and that the procedure according to claim 2 can also be carried out with a grinding wheel having in its peripheral region a tapered, for example tapered, contour and with the small diameter ahead on the narrow sides the indexable insert is guided. The advantage of this solution is based to a very special extent on the thereby improved cooling conditions on the surface of the grinding wheel and the indexable insert

For the three specified procedures, various embodiments are possible, which are specified in the dependent claims.

If in claims 1 and 2, the lead-in area is referred to as tapering forward, so it is based on a movement of the grinding wheel relative to a stationary in the axial direction indexable insert. In principle, however, only a relative movement between the indexable insert and the grinding wheel in the feed direction of the longitudinal loops is required, so that the term "to" is only an ordinal specification for the nature of the grinding wheel.

Since indexable inserts with a clearance angle have a larger and a smaller broadside, the question arises in which direction the grinding wheel is to be moved relative to the indexable insert. Basically, both directions of movement are possible, ie moving the cutting plate from the small broadside to the larger broadside and vice versa. However, it has been found that with hard sintered materials and high grinding performance it is better, according to a first embodiment of the method according to the invention, to guide the grinding wheels from the larger broad side of the indexable inserts over their narrow sides to the smaller broadside. The reason for this is that during grinding from the larger broad side, the endangered cutting edge in the region of the large transverse dimension breaks out less easily than when this cutting edge reaches from the narrow side through the grinding wheel becomes. Grinding pressure and thermal stress are then lower when grinding this cutting edge.

In the procedure according to claim 2 or 3, according to a further embodiment of the method also a peel grinding can be carried out.

According to a further advantageous embodiment, it is provided that the taper of the lead area and / or the trailing area (claims 1 and 2) or the entire tapered contour of the rotating grinding wheel (claim 3) are formed as a conical surface. The visible in longitudinal section circumferential lines of flow area, trailing area or grinding wheel are then straight. This is a production technology particularly favorable embodiment when dressing the grinding wheel. However, it must be mentioned that there is no compulsion to do so. The tapers can therefore also arched, z. B are executed as spherical surfaces or as fillets, where it depends very much on the special process control of the abrasive material to be ground

In many cases, in particular in the procedure according to claim 1, it is sufficient to carry out the entire gradation of grinding, ie from roughing to fine grinding, through the leading and trailing areas of the grinding wheel. Even with the conical grinding wheel according to claim 3, a finishing by longitudinal and peeling grinding in one go is possible. However, with very hard sintered materials and particularly high abrasive stress, it may also be necessary to distribute the grinding process on two grinding wheels. This is the subject of a further advantageous embodiment of the method according to the invention, wherein for roughing and finishing successive grinding operations with different grinding wheel specification but the same basic structure. The grinding machines required for this purpose, for example with pivotable grinding headstocks, which carry two grinding spindles, belong to the state of the art.

Despite the leading and trailing areas (claims 1 and 2), the grinding wheels required to carry out the methods according to the invention retain a relatively simple construction. Since the basically disc-shaped basic shape of the grinding wheel is maintained, the mutual accessibility of the indexable insert with the circular contoured circumferential surface, but also with the side surfaces of the grinding wheel, presents no difficulties. According to a further advantageous embodiment of the According to the method of the invention, it is therefore readily possible to also grind the chamfers of the indexable insert located between the narrow sides and the broad sides in the same clamping with the side surfaces of the rotating grinding wheel. With one and the same grinding wheel, the narrow sides of the indexable insert and the chamfers can thus be ground in one and the same clamping, which are arranged between the individual flat narrow sides or between the narrow sides and the broad sides of the indexable insert.

Finally, there is a particularly simple and thus advantageous possibility to carry out the method according to the invention when the indexable inserts need not have a clearance angle. The narrow sides of the indexable inserts then run perpendicular to their broad sides, and the relative pivotability of the grinding spindle and indexable insert about a particular pivot axis can be omitted.

The invention also relates to the use of a special grinding wheel for carrying out the grinding method according to claim 1 or 2 and the dependent claims 4 to 6 and 8 to 10 according to claim 11. According to the different grinding operations performed by the leading and trailing areas of the grinding wheel In each case, the cutting material material located on the circular contoured circumferential surface of the grinding wheel consists of diamond grains with a ceramic or metallic bond, the grinding wheel specification differing in the leading and trailing regions. The cutting material and its binding can be parked in the lead area especially on the needs of roughing and in the trailing area on the sizing, so z. B. be executed finer.

The use also includes a grinding wheel in which an abrasive coating is also provided on the side surfaces of the grinding wheel for grinding the chamfers, which may then again have a grinding wheel specification that is different from that in the circular contoured peripheral surface of the grinding wheel.

As has already been presented for the embodiment of the method, according to a further embodiment, the grinding wheel can have the taper of the lead-in area and / or of the trailing area in the form of a conical jacket, without it being necessary to stipulate for reasons of grinding technology.

Figur 1

zeigt eine Ansicht von oben auf die wesentlichen Teile einer Schleifmaschine, mit der das erfindungsgemäße Verfahren durchgeführt wird.

Figur 2A

ist eine Stirnansicht und ein Teilschnitt bei einer zu schleifenden Wendeschneidplatte.

Figur 2B

gibt eine Einzelheit aus dem Teilschnitt gemäß Figur 2A an.

Figur 3

zeigt einen Längsschnitt und eine Stirnansicht im Bereich der Werkstückaufnahme des Werkstückspindelstocks der Schleifmaschine gemäß Figur 1.

Figur 4

zeigt in einer Prinzipdarstellung die maßgeblichen Einflussgrößen beim Schleifen der Schmalseiten einer Wendeschneidplatte.

Figur 5

stellt den Schleifeingriff zu Beginn des Längsschleifens dar.

Figur 6

zeigt eine fortgeschrittene Phase des Schleifvorganges.

Figur 7

ist die Darstellung einer Schleifphase am Ende des Nachschleifens.

Figur 8

ist die Wiedergabe eines gegenüber den Figuren 4 bis 7 geänderten Schleifverfahrens, wobei die rotierende Schleifscheibe gegenüber der Wendeschneidplatte leicht geschwenkt ist.

Figur 9

zeigt eine der Figur 8 entsprechende Darstellung, wobei jedoch die rotierende Schleifscheibe eine geänderte Kontur hat.

Figur 10

verdeutlicht, wie bei dem erfindungsgemäßen Schleifverfahren auch Fasen mit derselben Schleifscheibe und derselben Aufspannung an die Wendeschneidplatte angeschliffen werden können.

Figur 11

ist eine der Figur 10 entsprechende Darstellung, wobei die Fase an der entgegengesetzten Seite der Wendeschneidplatte angeschliffen wird.

Figur 12

erläutert eine weitere Variante des erfindungsgemäßen Verfahrens, wobei die Schleifscheibe in ihrem Umfangsbereich durchgehend eine sich verjüngende Kontur hat.

The invention will be explained in more detail in the drawings illustrated embodiments. The figures show the following:

FIG. 1

shows a view from above of the essential parts of a grinding machine, with which the inventive method is performed.

FIG. 2A

is an end view and a partial section of an indexable insert to be ground.

FIG. 2B

gives a detail from the partial section according to FIG. 2A at.

FIG. 3

shows a longitudinal section and an end view in the region of the workpiece holder of the workpiece headstock of the grinding machine according to FIG. 1 ,

FIG. 4

shows in a schematic representation of the relevant factors influencing the grinding of the narrow sides of an indexable insert.

FIG. 5

represents the grinding engagement at the beginning of longitudinal grinding.

FIG. 6

shows an advanced phase of the grinding process.

FIG. 7

is the representation of a grinding phase at the end of re-sharpening.

FIG. 8

is the reproduction of one over the FIGS. 4 to 7 changed grinding process, wherein the rotating grinding wheel is slightly tilted relative to the indexable insert.

FIG. 9

shows one of the FIG. 8 corresponding representation, but with the rotating grinding wheel has a changed contour.

FIG. 10

illustrates how beveled with the same grinding wheel and the same clamping on the indexable insert in the inventive grinding process also bevels.

FIG. 11

is one of the FIG. 10 corresponding representation, wherein the chamfer is ground on the opposite side of the indexable insert.

FIG. 12

illustrates a further variant of the method according to the invention, wherein the grinding wheel in its peripheral region has a continuous tapered contour.

In FIG. 1 is a view from above schematically illustrated a grinding machine, as it corresponds to the usual universal round and -Unrundschleifmaschine. Only the essential parts are shown. On a machine bed 1, a grinding table 2 in the direction of a first displacement axis 3 is movable. The displacement axis 3 is commonly referred to in grinding machine construction as Z-axis. The grinding table 2 carries a workpiece headstock 4 with a receptacle 5 and a centering insert 6 At a distance from the Werkstockspindelstock 4 of the tailstock 7 is arranged with a centering 8 and a pressure pin 9. Workpiece headstock 4 and tailstock 7 can normally be moved against each other, but also together. At the centering insert 6, the indexable insert 10 to be ground can be fastened and centered and clamped by the pressure pin 9 of the tailstock 7.

The indexable insert 10 can be driven in rotation by the workpiece spindle 4. During grinding, therefore, the indexable insert 10 rotates about the driven axis of rotation 11. This is generally referred to as C-axis in grinding machine construction. At a distance from the grinding table 2, a wheel spindle 12 is arranged, which can be pivoted about a plane perpendicular to the plane of the pivot axis 13. The pivot axis 13 is commonly referred to as B axis. By means of a carriage 14, the wheelhead 12 can be moved relative to the grinding table 2 in the direction of the second displacement axis 15. The second displacement axis 15 is usually referred to in grinding machine construction as the X-axis.

The wheelhead 12 carries a first grinding spindle 16 with a first grinding wheel 18 and a second grinding spindle 17 with a second grinding wheel 20. Each of the two grinding wheels 18, 20 has a circular contoured peripheral surface 18a. The associated Rotation axes of the first and second grinding spindles 16, 17 and grinding wheel 18, 20 are designated by 19 and 21.

To the grinding machine also includes a dressing spindle 22 with a dressing wheel 23, to which the two grinding wheels 18 and 20 can be made to dress.

The pivotability of the grinding headstock 12 about the pivot axis 13 serves once to selectively bring the first grinding wheel 18 or the second grinding wheel 20 in sliding contact with the insert 10 and on the other hand, that the required pivoting movement of the grinding wheel can take place during grinding. The pivoting movement of the grinding headstock 12 about the pivot axis 13 is in this case included in the CNC control of the entire grinding machine.

• Rotation der Wendeschneidplatte 10 um die angetriebene Drehachse 11 (C-Achse),
• Verschieben der Wendeschneidplatte 10 über den Schleiftisch 2 in der Richtung der ersten Verschiebeachse 3 (Z-Achse),
• Verschieben des Schleifspindelstocks 12 relativ zum Schleiftisch 2 in Richtung der zweiten Verschiebeachse 15 (X-Achse),
• Verschwenken des Schleifspindelstocks 12 um die Schwenkachse 13 (B-Achse).

In the grinding machine for carrying out the grinding method according to the invention, four possible movements are thus coordinated with one another in a CNC-controlled manner:

• Rotation of the indexable insert 10 about the driven axis of rotation 11 (C-axis),
• Moving the indexable insert 10 over the grinding table 2 in the direction of the first displacement axis 3 (Z-axis),
• Moving the grinding headstock 12 relative to the grinding table 2 in the direction of the second displacement axis 15 (X-axis),
• Swiveling the grinding headstock 12 about the pivot axis 13 (B-axis).

The first and second displacement axis 3, 15 and the driven axis of rotation 10 lie in parallel planes; they can even all be in the same plane. The pivot axis 13 is perpendicular to these planes or this plane.

The CNC-controlled adjustment of the four movement possibilities is achieved in the manner of a non-circular grinding process that the narrow sides of the indexable insert 10 get the desired contour In this case, generally flat surfaces with bevels in the transition from the narrow sides to the two broad sides are desired.

In the FIGS. 2A and 2 B is to be ground indexable insert 10 with its details. Your broadsides 10a, b are already finished at the beginning of the grinding process. Indexable inserts are usually made of sintered carbide or ceramic materials; Even by sintering, broadsides 10a, b can be produced with sufficient accuracy and fineness. If higher accuracies are required, the broad sides are ground in a previous operation. The indexable inserts are used interchangeable and rotatable, for example by means of a mounting hole 26 in tool holders. They generally have a clearance angle 27 so that their narrow sides 24 are inclined relative to the broad sides. Therefore, one broad side 10a is larger than the other broadside 10b. The narrow sides 24 merge with bevels 25 into each other. Chamfers 28 can also be incorporated in the transition between the narrow sides 24 and the broad sides 10a, 10b, compare this FIG. 2B , For this purpose, a chamfer angle 29 is produced in the edge area. In the broad sides 10a, 10b of the indexable inserts, depressions 30 may be located, or the broad sides 10a, 10b may be formed by the depressions 30. In certain applications, the clearance angle 27 may be omitted, so that the narrow sides 24 are vertical to the broadsides 10a, b run. The individual angles depend on the intended use of the indexable insert 10, in particular after the Zerspanaufgabe and the material to be machined, which is to be machined with the indexable insert 10.

The FIG. 3 shows an enlarged view of details of the workpiece stub spindle. The already mentioned receptacle 5 is fastened with screws 32 on the receiving part 31 for the workpiece headstock 4. The receptacle 5 comprises the clamping insert 6, which is provided in its longitudinal direction with stepped holes. In this longitudinally movable is a centering pin 37 which is biased by a compression spring 34 in the direction of the tailstock 7. The compression spring 34 is supported with its inner end on a pressure plate 35. The pressure plate 35 also serves to support the centering pin 37 with a nut 36. By rotation about the driven axis of rotation 11 of the clamping insert 6 is driven to rotate. The indexable insert 10 is attached to the centering pin 37 and at the same time supports itself on the shoulder of the clamping insert 6. Since the workpiece headstock 4 and tailstock 7 can be adjusted against each other, the indexable insert 10 is clamped between the clamping insert 6 and the pressure pin 9 of the tailstock 7 and taken to rotate non-positively. The illustrated allows Construction also a fast, suitable for mass production replacement of the grinding indexable inserts. The partial handling for loading and unloading preferably takes place fully automatically in or out of the device

In FIG. 4 the grinding process is illustrated schematically and with its basic influencing variables. The indexable insert 10, which is provided with a grinding allowance 38, is driven to rotate about the driven rotation axis 11. The extended surface of a narrow side 24 forms the geometric determination line 39 for the grinding process of this narrow side.

The grinding wheel 18 rotates about its axis of rotation 19, wherein the actual grinding body is clamped as usual between two clamping flanges 40. The rotating peripheral surface 18a of the grinding wheel 18 is contoured in a circular shape, i. h., That in each radial plane of the grinding wheel is a circular contour. In this case, however, the grinding wheel 18 is composed of a feed region 41 and a trailing region 42 in its abrasive region. The flow area 41 is tapered in the axial direction. From a largest diameter 43 of the grinding wheel 18, it reduces to a smaller diameter of its front side surface. The front side surface is defined by the feed direction 44, in which the relative movement of the grinding wheel 18 relative to the indexable insert 10 takes place along the geometric determination lines 39. In this case, the indexable insert 10 can be moved and the grinding wheel stand in the axial direction or vice versa.

In FIG. 4 the contour of the feed area 41 is shown as a cone contour. In the FIG. 4 apparent generatrix of the lead-in area 41 is thus a straight line. However, this is by no means mandatory, depending on the technological requirements of the cutting process, the surface line can also be curved, z. B. spherical or shaped as a groove. These shapes can also be freely determined depending on the shape of the workpiece and the grinding task FIG. 4 is also shown that the mutual movement between the grinding wheel 18 and the indexable insert 10 in the feed direction 44 starts at the larger broad side 10a and ends at the smaller broad side 10b. This is the generally preferred direction of grinding; because it reduces the risk that the peripheral edge of the indexable insert 10, which is located between the broad side 10a and the narrow side 24, breaks out during grinding. In principle, however, it is also possible to work with different grinding direction, so that the mutual movement attaches to the smaller broadside 10b.

The lead-in region 41 is adjoined by a trailing-off region 42, which in the present case is contoured in a cylindrical manner, so that the diameter of the trailing region is at the same time the largest diameter of the leading region. In the region of the largest diameter 43, the two areas merge into one another.

The grinding process is controlled in such a way that with the lead area 41 a peel grinding in the sense of pre-grinding and with the trailing area 42 a regrinding peel grinding is known, the grinding wheel 48 delivered so that the entire grinding allowance 38 is removed in a single longitudinal passage While the peeling grinding is performed with a tapered contour of the lead-in area, there is a line contact between the trailing area 42 and the narrow side 24 of the indexable insert 10 during regrinding.

The grinding process is based on a longitudinal grinding, wherein the grinding wheel 18 is guided relative to the indexable insert 10, as in detail in the FIGS. 1 to 7 is illustrated. The FIGS. 5 to 7 show the enlarged detail U from the FIG. 4 , but in advanced stages of the grinding process.

The roughing and regrinding can be carried out as roughing and finishing. In certain applications, ie with particularly difficult to machine sintered materials, it may be appropriate to distribute roughing and finishing on two different grinding wheels, as the grinding machine according to FIG. 1 allows in a known manner. The two grinding wheels 18 and 20 in this case have the same basic structure but different grinding wheel specification

Even if the machining process is always based on longitudinal grinding, it must always be borne in mind that the four different movements listed above must always be adjusted in a CNC-controlled manner so that the desired result can be achieved.

The progress of longitudinal grinding is particularly evident in the FIGS. 4 to 7 in connection. According to FIG. 4 the grinding wheel 18 is first brought to the indexable insert 10 and touches the Schleifmaßmaß 38 straight with the lead-in at the Place the larger broadside 10a. In the phase of FIG. 5 a large part of the grinding allowance has already been removed by the lead-in area 41, and the caster area 42 is currently being used. According to FIG. 6 If there is a complete line contact between the trailing edge region 42 and the pre-ground narrow side 24 While pre-grinding is not yet complete, re-sharpening already starts with the entire axial extension of the trailing region 42. In FIG. 7 the regrind with the tail region 42 is just over, and the grinding process is so far completed It should be noted that the chamfers 25 are mitgeschliffen between the individual narrow sides 24 in the course of the grinding process described here

Based on FIG. 8 a grinding process is described, compared to the FIGS. 4 to 7 shown grinding process is changed.

The reference numerals for the illustrated parts of the grinding machine and the indexable insert have remained unchanged. However, a new sequence of reference numerals for the rotating grinding wheel 48 is introduced because, although the latter has remained unchanged, it is moved in a changed pivotal position relative to the indexable insert 10. While according to FIG. 4 the grinding wheel 18 is perpendicular to the surface line of the narrow sides 24, the grinding wheel 48 is in the illustration according to FIG. 8 pivoted forward by the tilt angle 47. This can be easily adjusted and maintained by means of the pivot axis 13. The grinding wheel 48 again has a forwardly tapering lead-in area 49 and a cylindrical trailing area 50. The circular contoured peripheral surface 48a thus forms a lead angle 45 in the lead area 49 opposite the resulting narrow side 24 of the indexable insert 10 and a clearance angle 46 in the trailing area 50. The clamping flanges of the rotating grinding wheel 48 are again denoted by 40, their axis of rotation 51 and their largest diameter 52.

The grinding wheel 48 is guided relative to the indexable insert 10 in the feed direction 44 along a longitudinal grinding on the narrow side 24 of the indexable insert 10 along. In this case, peeling grinding is preferred.

Here, in the trailing region 50 is no longer a line contact with the narrow side 24 of the insert 10 instead, but only a point contact by the largest diameter 52 It has been shown that in this way, the desired Contours on the narrow sides 24 of the indexable insert 10 are to work out reliably. In this case, the entire processing can be done by peeling grinding If the grinding allowance 38 to be processed is higher, however, the grinding of the contour can take place in several steps; ie the grinding allowance is removed step by step. The clearance angle 46 in the trailing region 50 leads to improved cooling conditions because the line contact between the indexable insert 10 and the trailing region 50 is canceled.

FIG. 9 has a variant of that through the FIG. 8 illustrated process flow to the subject. The contour of the trailing region 50 is no longer cylindrical in this case, but counter to the feed direction 44 of the longitudinal grinding, ie tapered towards the end of the grinding wheel 48. The contour of the taper may preferably be conical, although other contours are readily conceivable. With the modified shape of the grinding wheel according to FIG. 9 For example, a larger lead angle 53 in the lead-in area and also a larger clearance angle 44 in the lead-in area 50 can be realized without the grinding wheel 48 having to be tilted even more than the side face 24 of the indexable insert 10. This shows very quickly a comparison of the cutting angle 47 according to the FIGS. 8 and 9 , Also in the method according to FIG. 9 can be realized easily a longitudinal grinding.

Finally, in the Figures 10 and 11 illustrated how chamfers 28, which are located in the transition region between the broad sides 10 a, b and the narrow sides 24, can be ground with the same grinding wheels 18, which serve for grinding the narrow sides 24. For this purpose, the broad sides 55, 56 of the grinding wheel 18 are also provided with an abrasive coating and are laterally obliquely to the transition region between the broad sides 10 a, b and the narrow sides 24 of the indexable inserts 10 employed.

For carrying out the previously described grinding method according to the invention thus grinding wheels are required, which have two different areas in the axial direction, namely a lead-in area 41, 49 and a trailing area 42, 50 During the lead-in area 41, 49 to the first side surface 55 of the grinding wheel 18, 48th formed tapering, the trailing region 42, 50 may be cylindrical or also tapering towards the second side surface 56. Since indexable inserts 10 are made of sintered cemented carbide or ceramic materials, the cutting material is made by diamond grains with ceramic or metallic Bond formed. As a rule, the grinding wheel specification will be different in the advance area 41, 49 than in the trailing area 42, 50 because the lead area 41, 49 generally works in the sense of pre-grinding, ie has to remove larger quantities of material compared to the trailing area 42, 49 and works coarser. The tracking area 42, 50 can be set finer and softer in its grinding specification; because of the wake area above all the required surface finish must be achieved.

The abrasive pads on the side surfaces 55, 56 of the abrasive wheels 18, 48 are also formed of ceramic or metal-bonded diamond grains and will again have a different grinding wheel specification than they do in the art, in accordance with their task of grinding the chamfers 28 to the indexable insert 10 Leading 41, 49 or in the wake area 42, 50 is present.

It has even been found that advantageous results can be achieved if the method is carried out with a grinding wheel which has no trailing area. The grinding wheel is then practically only from the lead-in area, so in its peripheral region has a tapered, in the simplest case, tapered contour and is guided with the smaller diameter ahead over the narrow sides of the indexable inserts. This case is FIG. 12 shown.

In FIG. 12 First, the indexable insert 10 is again shown with their broad sides 10 a, b and their narrow sides 24. The reference numerals for this have remained unchanged as well as those for the workpiece holder of the grinding machine and the four relevant axes of motion C, BX and Z. Notwithstanding the foregoing, the circular contoured peripheral surface 58 of the grinding wheel 57 here has a continuous continuous tapered contour, in the illustrated embodiment that of a conical mantle with rectilinear generators. The cone shape is not mandatory. Indexable insert 10 and grinding wheel 57 are again tilted or pivoted about the tilting angle 60 and are guided relative to one another in the sense of a longitudinal grinding. In this case, the peripheral edge 61 formed on the larger side surface 63 of the grinding wheel 57 is in sliding contact with the indexable insert 10, and the smaller side surface 62 of the grinding wheel has in the feed direction 64 of the longitudinal grinding forward. As can be seen, a lead angle 59 between the peripheral surface 58 of the grinding wheel 57 and the narrow side 24 of the indexable insert 10 is again formed. <u> List of Reference Numbers </ u> 1 machine bed 2 grinding table 3 first displacement axis (Z-axis) 4 Workhead 5 admission 6 Clamp insert 7 tailstock 8th centering 9 pushpin 10 Indexable insert 10a, b broadside 11 driven rotary axis (C-axis) 12 Wheelhead 13 Swivel axis (B-axis) 14 carriage 15 second displacement axis (X-axis) 16 first grinding spindle 17 second grinding spindle 18 first grinding wheel 18a circular contoured peripheral surface 19 first axis of rotation 20 second grinding wheel 21 second axis of rotation 22 dressing spindle 23 dressing wheel 24 narrow side 25 Chamfer (narrow side) 26 mounting hole 27 clearance angle 28 Chamfer (broadside) 29 bevel angle 30 trough 31 receiving part 32 screw 34 compression spring 35 printing plate 36 mother 37 centering 38 Grinding 39 geometric destination line 40 clamping flange 41 leading area 42 running area 43 largest diameter 44 Feed direction of the longitudinal grinding 45 Bleed angle of the flow area 46 Clearance angle of the trailing area 47 tilt angle 48 grinding wheel 48a circular contoured peripheral surface 49 leading area 50 running area 51 axis of rotation 52 largest diameter 53 Bleed angle of the flow area 54 Clearance angle of the trailing area 55 first side surface 56 second side surface 57 grinding wheel 58 circular contoured peripheral surface 59 lead angle 60 tilt angle 61 large peripheral edge 62 small side surface 63 large side surface 64 Feed direction of the longitudinal grinding

Claims (13)

1. Method for grinding an indexable cutting insert (10), in which the narrow sides (24) thereof are moved along the circularly contoured circumferential surface (18a) of a rotating grinding disc (18) and are ground by the latter, with the following movements of the grinding operation which are coordinated with one another under CNC control:

   a) the indexable cutting insert (10) is driven in rotation about a rotational axis (11) that extends perpendicularly to the plane thereof;

   b) a grinding spindle (16), which mounts and drives the grinding disc (18), and also the rotational axis (11) of the indexable cutting insert (10) are displaced in relation to one another in two displacement axes (3, 15) that extend perpendicularly to one another, wherein the displacement axes (3, 15) and the rotational axis (11) are located in parallel or identical planes;

   c) the grinding spindle (16) and the indexable cutting insert (10) are pivoted in relation to one another about a pivot axis (13) which is perpendicular to the planes in which the displacement axes (3, 15) and the rotational axis (11) of the indexable cutting insert (10) are located,
   characterized by the following procedure:

   d) the grinding operation is based on longitudinal grinding, wherein the circularly contoured circumferential surface (18a) of the rotating grinding disc (18) is guided in relation to the narrow sides (24) of the indexable cutting insert (10) from one broad side (10a) to the other broad side (10b) of the indexable cutting insert (10);

   e) during the longitudinal grinding, a leading region (41) which is located on the grinding disc (18) and narrows towards the front is guided forwards, said leading region acting on the narrow sides (24) of the indexable cutting insert (10) by peel grinding for the purpose of rough grinding;

   f) the trailing region (42) of the grinding disc (18), said trailing region adjoining the leading region (41) and being located at the rear during longitudinal grinding, has a cylindrical shape and acts on the narrow sides (24) of the indexable cutting insert (10) by linear contact for the purpose of re-grinding.
2. Method for grinding an indexable cutting insert (10), in which the narrow sides (24) thereof are moved along the circularly contoured circumferential surface (48a) of a rotating grinding disc (48) and are ground by the latter, with the following movements of the grinding operation which are coordinated with one another under CNC control:

   a) the indexable cutting insert (10) is driven in rotation about a rotational axis (11) that extends perpendicularly to the plane thereof;

   b) a grinding spindle (16), which mounts and drives the grinding disc (48), and also the rotational axis (11) of the indexable cutting insert (10) are displaced in relation to one another in two displacement axes (3, 15) that extend perpendicularly to one another, wherein the displacement axes (3, 15) and the rotational axis (11) are located in parallel or identical planes;

   c) the grinding spindle (16) and the indexable cutting insert (10) are pivoted in relation to one another about a pivot axis (13) which is perpendicular to the planes in which the displacement axes (3, 15) and the rotational axis (11) of the indexable cutting insert (10) are located,
   characterized by the following procedure:

   d) the grinding operation is based on longitudinal grinding, wherein the circularly contoured circumferential surface (48a) of the rotating grinding disc (48) is guided in relation to the narrow sides (24) of the indexable cutting insert (10) from one broad side (10a) to the other broad side (10b) of the indexable cutting insert (10);

   e) during the longitudinal grinding, a leading region (49) which is located on the grinding disc (48) and narrows towards the front is guided forwards, said leading region acting on the narrow sides (24) of the indexable cutting insert (10) by peel grinding for the purpose of rough grinding;

   f) the trailing region (50) of the grinding disc (48), said trailing region (50) adjoining the largest diameter (52) of the leading region (49) and being located at the rear during longitudinal grinding, is formed in a cylindrical manner starting from this diameter (52) or in a manner narrowing towards the end;

   g) the rotating grinding disc (48) is guided in such a pivoted position with respect to the narrow sides (24) of the indexable cutting insert (10) that the leading region (49) forms a chamfer angle (45, 53) and the trailing region (50) forms a clearance angle (46, 54) with respect to the narrow sides (24), and punctiform grinding contact between the largest diameter (52) of the grinding disc (48) and the narrow sides (24) of the indexable cutting insert (10) arises.
3. Method for grinding an indexable cutting insert (10), in which the narrow sides (24) thereof are moved along the circularly contoured circumferential surface (58) of a rotating grinding disc (57) and are ground by the latter, with the following movements of the grinding operation which are coordinated with one another under CNC control:

   a) the indexable cutting insert (10) is driven in rotation about a rotational axis (11) that extends perpendicularly to the plane thereof;

   b) a grinding spindle, which mounts and drives the grinding disc (57), and also the rotational axis (11) of the indexable cutting insert (10) are displaced in relation to one another in two displacement axes (3, 15) that extend perpendicularly to one another, wherein the displacement axes (3, 15) and the rotational axis (11) are located in parallel or identical planes;

   c) the grinding spindle and the indexable cutting insert (10) are pivoted in relation to one another about a pivot axis which is perpendicular to the planes in which the displacement axes (3, 15) and the rotational axis (11) of the indexable cutting insert are located,
   characterized by the following procedure:

   d) the grinding operation is based on longitudinal grinding, wherein the circularly contoured circumferential surface (58) of the rotating grinding disc (57) is guided in relation to the narrow sides (24) of the indexable cutting insert (10) from one broad side (10a) to the other broad side (10b) of the indexable cutting insert (10);

   e) the rotating grinding disc (57) has, in its circumferential region, a narrowing contour and is guided with the smaller diameter at the front over the narrow sides (24) of the indexable cutting insert (10);

   f) the rotating grinding disc (57) is guided in such a pivoted position with respect to the narrow sides (24) of the indexable cutting insert (10) that its circumferential surface (58) forms a chamfer angle (59) with respect to the narrow sides (24), and punctiform grinding contact between the largest diameter of the grinding disc (57) and the narrow sides (24) of the indexable cutting insert (10) arises.
4. Method according to one of Claims 1 to 3, characterized in that the relative movement between the rotating grinding disc (18, 48) and the indexable cutting insert (10) during longitudinal grinding starts at the larger broad side (10a) of the indexable cutting insert (10) and ends at the smaller broad side (10b).
5. Method according to Claim 2 or 3, characterized in that the longitudinal grinding takes place by peel grinding.
6. Method according to Claim 1 or 2, characterized in that the narrowing of the leading region (41, 49) and/or of the trailing region (50) is formed as a conical surface.
7. Method according to Claim 3, characterized in that the narrowing contour of the rotating grinding disc is formed as a conical surface.
8. Method according to one of Claims 1 to 7, characterized in that, for the purpose of roughing and finishing, successive grinding operations are provided with grinding discs (18, 20) having different grinding disc specifications but the same basic structure.
9. Method according to one of Claims 1 to 8, characterized in that bevels (28), located between the narrow sides (24) and the broad sides (10a, b), of the indexable cutting insert (10) are initially ground in the same setup with the lateral surfaces (55, 56) of the rotating grinding disc (18).
10. Method according to one of Claims 1 to 3 and 5 to 9, characterized in that, when indexable cutting inserts without an undercut are ground, the relative pivotability of the rotating grinding disc and the indexable cutting insert about a particular pivot axis is dispensed with.
11. Use of a grinding disc which has a circularly contoured circumferential surface (18a, 48a), having the following features:

    a) the grinding disc (18, 48) has two different regions in the axial direction at least in its circumferential region;

    b) starting from the largest diameter of the circularly contoured circumferential surface (18a, 48a), the first region is formed in a manner narrowing towards a first lateral surface (55);

    c) the second region, adjoining the largest diameter of the first region, is formed in a cylindrical manner or in a manner narrowing towards the second lateral surface (56);

    d) the cutting material consists of diamond grains with a ceramic or metallic bond, wherein the grinding disc specification is different in the two regions;

    characterized in that the grinding disc (18, 48) is used to carry out the grinding method according to Claim 1 or 2 and Claims 4 to 6 and 8 to 10 that refer back thereto, wherein the first region is used as the leading region (41, 49) during longitudinal grinding and the second region is used as the trailing region (42, 50) during longitudinal grinding.
12. Use according to Claim 11, wherein at least one of the grinding disc lateral surfaces (55, 56) is also provided with a grinding coating, the cutting material of which consists of ceramic- or metal-bonded diamond grains and the grinding disc specification of which is different from that in the circularly contoured circumferential surface (18a, 48a) of the grinding disc (18, 48).
13. Use according to Claim 11 or 12, wherein the narrowing of the leading region (41, 59) and/or of the trailing region (42, 50) is formed as a conical surface.

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