RU192840U1 - END MILL - Google Patents

Abstract

An end mill comprising a shank, a body, an axis, an end plane located perpendicular to the axis, main helical cutting teeth resting on the back of the head, and additional helical cutting teeth resting on the back of the head located on the body, the main helical teeth with the backs extending from the end the plane to the shank, and additional helical teeth with occiput have a length equal to 30% of the length of the main teeth when counting from the end plane; the number of additional teeth is equal to the number of main teeth. On each additional tooth there are chip separating grooves, which, in combination with the teeth located between them, form a chipbreaker for grinding in the end part of the chip obtained when milling into small parts with the possibility of removing these small particles with compressed air or under coolant pressure, and the chip separation grooves of each additional tooth are located along the helical line at the same, respectively, distance and from the end plane and begin at a distance of 0.9 mm from the end plane, and the chip cutting grooves themselves are rectangular in shape with a width of 0.6 mm and a depth of 0.45 mm, the width of the teeth is 0.6 mm, while the chip breaker pitch is 1.2 mm

Description

The technical field to which the utility model relates.

The utility model relates to cutting tools for metal working, in particular to end mills.

State of the art

The invention is known RU 2392095 C1 End mill. The essence of this invention is that in addition to the existing teeth with side cylindrical cutting blades and end cutting blades, the intersection of which are the tops of the teeth located on the side surface of the cutter, two additional end cutting blades are made. These additional end blades are short and therefore not in contact with the side cylindrical surface of the cutter. The purpose of this invention is the possibility of cutting the mill in the axial direction, which is important when milling keyways.

The invention is known RU 2394670 C1 End mill with torsional rigidity. The essence of this invention is to create a profile of the cutter tooth having enlarged chip grooves for ejecting (retracting) the chip to facilitate the operation of the cutter and provide increased rigidity.

Known end mill with crowns made of hard alloy GOST 20534-75 with oblique teeth. The oblique teeth of this cutter are located on a cylindrical surface, which includes the cutting part of the cutter.

Known end mill with soldered carbide helical plates GOST 20538-75. The helical teeth of this cutter are located on a cylindrical surface, which includes the cutting part of the cutter.

Known end mill patent RU 2568231 C1, 2015. In this mill, in addition to the main teeth, there are additional teeth at the end part of the mill, as in utility model No. 125502. (Authors Cherkashin V.P., Vodilov A.V.) 2013. But the similarity ends there. Utility model No. 125502 has main teeth straight and additional oblique.

Known end mill RU 2573858 C1. Here a new principle of designing an end mill body different from the standard is proposed.

Known US patents No. 6231275 B1, No. 6439811 B1. In these patents, a change in the cutting angles is applied to improve the roughness of the machined surface.

Known patents RU 2507038 C1, RU 1537414 C1, where the cutting edges of the teeth are made with chip separation grooves. End mills with chip separating grooves and chip breakers degrade the cleanliness of the surface and increase the roughness.

The teeth with chip separating grooves appeared a long time ago and had the goal of cutting a long drain chip for its better removal and transportation. Chip separation grooves were made at a great distance from each other; for example, two (or even one) chip separating grooves along the entire length of the cutter tooth.

Chip separating grooves are narrow grooves cut across the cutting teeth or what is the same across the cutting blades; a cutting blade is a sharpened, sharpened portion of a cutting tooth.

Chisels with chipbreakers appeared because of the need to mill modern difficult to process materials or for milling conditions, when it is very difficult to remove chips. Chipbreakers are performed over the entire length of the cutting teeth of modern milling cutters; this impairs the cleanliness and roughness of the machined surface and such cutters are mainly used for roughing.

Chipbreakers are small teeth on the teeth. Between the teeth there are hollows, which are chip separating grooves. The width of the teeth and the width of the chip separation grooves are the same (or comparable). That is, the step of the chip separation grooves is approximately equal to their doubled width. Chipbreakers are needed for grinding chips into small pieces, which facilitates its removal from the cutting zone. Note that usually a milling cutter with small teeth on the teeth is called a milling cutter with chipbreakers. The space between the teeth is chip separation grooves. We also note that chipbreakers visually are serrated on the teeth.

Traditionally, the cutting blade of a tooth cutter has a straightforward appearance. If chip breakers, that is, teeth, are made on the blades of these teeth, then the width of these teeth is what remains of the rectilinear blade, that is, only areas from the rectilinear blade that became known as teeth are left.

The chipbreakers on the tooth are small teeth (the teeth are part of the rectilinear tooth blade in size equal to the distance between the chip separating grooves) on the teeth; the width of the tooth and the distance between the teeth are approximately the same (or comparable). The shape of the teeth is different, the geometric shape of the depressions (distances) between the teeth, that is, chip separation grooves) is also different, including the simplest rectangular one, which is presented in this proposed utility model.

Each geometric shape (or profile) of the teeth (or chipbreakers) corresponds to the geometric shape of the chip separation groove between them. The tops of the teeth can be rounded in radius; this increases durability but complicates technology and editing.

For a clearer understanding of what a chipbreaker is for this section of the “Prior Art”, an informational figure 1 is presented in the appendix to the application, containing a typical standard end mill with chipbreakers (small teeth) on the teeth; This is an addition to the verbal text; (Internet resource).

Known utility model No. 125502. In this utility model No. 125502 V23C. End mill of increased resistance (authors Cherkashin V.P., Vodilov A.V.) the main teeth of the mill are straight, and the additional teeth (of lesser length) located in the same mill are oblique.

Known utility model No. 153802. In this utility model No. 153802 В23С The combined end mill of increased resistance (authors Cherkashin V.P., Vodilov A.V.) the end part of the mill containing oblique additional teeth is interchangeable.

Known utility model No. 158628. In this utility model No. 158628 V23C, an end mill with interchangeable cutting inserts having increased resistance (authors Cherkashin V.P., Vodilov A.V.) in the end part of the mill containing end cutting inserts, additional end cutting inserts are installed on the non-working side of the grooves having both end and side cutting blades.

Known design of the end mill from an article in the journal STIN (Machines and tools) 2013, No. 9, p. 23-28. Analysis of the temperature fields of the end mill with equal resistance of the side and end cutting blades when milling hard-to-work steels. Authors of the article Cherkashin V.P., Vodilov A.V. In this design, the main cutting teeth of the mill are helical, in the end part of the mill, cutting teeth with a length equal to 30% of the main teeth are also helical.

This article is from STIN Magazine (Machine Tools and Instruments) 2013, No. 9 p. 23-28 was reprinted in an English journal. Temperature fields of a face mill with uniform cutter life in milling hard steel Cherkashin, V .; Vodilov, A. May 7, 2014. Russian Engineering Research. Russian Engineering Research, 2014, Vol. 34, No. 4, pp. 261-265. © Allerton Press, Inc., 2014. Original Russian Text © V.P. Cherkashin, A.V. Vodilov, 2013, published in STIN, 2013, No. 9, pp. 23-28. Temperature Fields of a Face Mill with Uniform Cutter Life in Milling Hard Steel a b V.P. Cherkashin and A.V. Vodilov OMT OJSC, Moscow Tikhomirov Research Institute of Instrument Design

An article in the journal STIN (Machines and Tools) 2013, No. 9, pp. 23-28 (authors Cherkashin V.P., Vodilov A.V.) has been placed in the largest libraries, including the library of the Saratov State Technical University (GTU), in the libraries of Omsk State Technical University, Altai State Technical University, Amur State Technical University, Penza State Technical University, Bryansk State Technical University.

The design of the end mill from the journal STIN (Machines and Tools) 2013, No. 9, p. 23-28 (authors Cherkashin V.P., Vodilov A.V.) was taken as a prototype of the proposed utility model and was used for the manufacture of coal mining combines (Selecting the parameters of the terminal milling cutters with equal resistance of side and end cutting blades for processing stars of feed mechanism propellers. Mining Equipment and Electromechanics Journal. 2012. No. 10, pp. 7-11, author Cherkashin VP).

In article 1350 of the Civil Code of the Russian Federation “Condition for patentability of inventions” in paragraph 2, the following is stated.

An invention (utility model) is new if it is not known from the prior art.

An invention (utility model) has an inventive step, if for a specialist it does not explicitly follow from the prior art.

The prior art for the invention (utility model) includes any information that has become available at the time of application.

For a clearer and more visual representation of what a prototype is in the annex to the application, information figure 2 is presented; addition to the verbal text. This design cutters from the magazine journal STIN (Machines and tools) 2013, No. 9).

In this application, the section "Prior Art" has a special, non-standard form, as informational figures 1 and 2 are attached to this section.

Information figure 1 is a general view of cutting teeth with chipbreakers ₃ cognitive drawing.

Information Figure 2 is a prototype drawing. This drawing is taken from the journal STIN. This is also an educational drawing.

In general, the information figures 1 and 2 are not drawings of a utility model. If the substantive examination decides that Figures 1 and 2 are an excess of information, then these figures are canceled from the section "Prior Art".

The end part of the mill refers to the part of the mill with a length equal to the length of the additional teeth when counting from the end plane of the mill.

The end part of the cutter wears out more than the part of the cutter that does not contain the end part. This is due to the presence of secondary cutting of the chip with insufficient removal of it from the cutting zone, and also because the end part is loaded more often due to the presence of milling technology with a gradual deepening of the cutter by the length of the end part, milling with simultaneous radial and axial feed.

The design of the cutter from STIN Magazine (Machines and Tools) 2013 No. 9 has the peculiarity that it contains at the end part additional teeth of a lesser extent, comprising 30% of the main teeth along the length. These additional teeth help the cutting operation of the main teeth, which have a large length, increasing the resistance of the most wear, end part of the cutter and, therefore, increasing the resistance of the cutter as a whole. This mill works satisfactorily when milling planes, ledges, wide grooves.

But when milling closed complex surfaces of parts, there are difficulties associated with poor removal of chips from the cutting zone, jamming of chips in the teeth of the cutter, accumulation in the chip groove, compaction, packing and, as a result, breakage of the cutter (and sometimes tooth wear due to secondary cutting chips). The complex profile surface of a part is a combination of surfaces of revolution and planes, holes, deep grooves, pockets, various kinds of recesses. When processing closed such surfaces, the cutting zone is closed to remove chips and the chips accumulate in the cutting zone, which is unacceptable for a normal cutting process. Note that a typical element of a complex profile surface that is most difficult to mill due to insufficient chip removal is a narrow and deep groove, that is, a groove equal in width to the diameter of the cutter and in depth equal to the length of the main teeth. In addition, the end part of the cutter enters the cutting work much more often than the rest of the cutter, which does not contain additional teeth due to the presence of radial feed simultaneously with the axial feed, which occurs when machining on CNC machines.

Currently, end mills are manufactured by SKIF (Russia), ISCAR (Israel), PRAMET (Czech Republic), WALTER (Germany).

In these companies, for machining closed complex surfaces, interchangeable end parts in end mills are provided. The end parts are most susceptible to the accumulation of chips (with the vertical position of the cutter) and in connection with this there is the possibility of breaking the cutter tooth, or the body (body) of the cutter itself. If a breakdown occurs, the replaceable end part is replaced with a spare.

On the website of the industrial Internet portal WWW.mirprom.ru, in the section “Features of the tool for high-performance milling at machining centers”, the following information from SKIF (Russia) is presented “One of the problems of the process of machining complex surfaces of parts by milling is the possibility of packing chips in the cutting zone and, accordingly, damage to the cutter, part or the machine itself. When roughing large-sized parts of complex shape, the most vulnerable part of prefabricated end face-cylindrical mills is the lower row of teeth (with the vertical position of the milling cutter) having a shorter resource. The optimal solution is a removable face cutting part significantly reduces operating costs and increases the resource of an expensive mill body. ”

This refers to the lack of resources on the condition of damage, static breakage and malfunction of the cutter while still working, not worn cutter teeth blades.

In the operating instructions of almost all milling cutters, the need to remove chips with compressed air or under pressure with coolant is indicated, but when milling complex surfaces, especially in the presence of drain chips, blowing chips with air or washing with liquid is difficult.

With a relatively poor, relatively insufficient removal of chips from the cutting zone, chip shavings do not occur, but secondary chip cutting occurs. This greatly increases the wear of the cutters, but this amount of wear can be predicted and even calculated.

With virtually no removal or with completely insufficient removal of chips from the cutting zone (for normal operation of the cutter), the chip is refilled and the cutter body breaks. That is, here the milling cutter breaks down when the cutting teeth blades are still working and not blunt and worn out. This occurs when milling parts of complex shape, when it is difficult to remove chips and when milling viscous metals, when there is a drain chip, that is, chips having the form of a continuous tape. The drainage chip not only clogs the chip flutes, but is also washed onto the teeth, making the cutting process more difficult.

In production conditions, for some mills, the problem is solved by the supply of replaceable end parts.

The end mill (STIN magazine (Machines and tools) 2013 No. 9) contains a shank, a body, an axis, an end plane located perpendicular to the axis, main helical cutting teeth resting on the nape, and additional helical cutting teeth resting on the nape located on the body, and the main helical teeth with a nape have a length from the end plane to the shank, and additional helical teeth with a nape have a length equal to 30% of the length of the main teeth when counting from the end plane; the number of additional teeth is equal to the number of main teeth. The teeth are screw fastened by soldering.

The design of the cutter (published in the journal STIN (Machines and Tools) 2013, No. 9, was taken as a prototype of the proposed utility model.

In this section "Prior Art", applicants do not have an unequivocal opinion whether informational figures 1 and 2 are an excess of information or not. If the examination considers that information figures 1 and 2 are an excess of information and are not needed, then these information figures need to be simply extinguished, that is, cut out.

1) Disclosure of a utility model

The prototype is the design of the end mill, published in the journal STIN (Machines and Tools) 2013 No. 9, pp. 23-28 Analysis of the temperature fields of the end mill with equal resistance of the side and end cutting blades when milling difficult to steel. The authors of the article are Cherkashin V.P., Vodilov A.V., containing a shank, a body, an axis, an end plane located perpendicular to the axis, the main helical cutting teeth resting on the nape, and additional helical cutting teeth resting on the nape located on the body moreover, the main helical teeth with a nape have a length from the end plane to the shank, and the additional helical teeth with a nape have a length equal to 30% of the length of the main teeth when counting from the end plane; the number of additional teeth is equal to the number of main teeth. These prototype data are included in the restrictive part of the utility model formula.

(This is essentially a limiting part of the proposed utility model).

Helical cutting teeth are brazed screw cutting inserts.

The disadvantage of the prototype is as follows.

The disadvantage of the prototype is manifested when milling closed complex surfaces, when there are difficulties associated with poor removal of chips from the cutting zone, jamming of chips in the teeth of the cutter, accumulation in the chip groove, compaction, packaging and, as a result, breakage of the cutter. The complex profile surface of a part is a combination of surfaces of revolution and planes, holes, deep grooves, pockets, various kinds of recesses. When processing closed such surfaces, the cutting zone is closed to remove chips and the chips accumulate in the cutting zone, which is unacceptable for a normal cutting process. Note that a typical element of a complex profile surface that is most difficult to mill due to insufficient chip removal is a narrow and deep groove, that is, a groove equal in width to the diameter of the cutter and in depth equal to the length of the main teeth.

In the prototype, the end part of the cutter and especially its lower part (with the vertical position of the cutter) work in difficult and often unsatisfactory cutting conditions. The chips clog the chip groove, can be wound on the teeth (especially if the chips are drain or close to the drain), can not be removed from the cutting zone under pressure by cooling liquid or compressed air, which threatens the breaker milling, that is, reducing the cutter life by the condition of breaking elements cutters, cutter body or its teeth.

We emphasize that for some milling cutters, the task of increasing the resource is solved by manufacturing and supplying replaceable end parts.

In the prototype (as in other end mills), the chip groove is the space between the teeth and the back of the head, where the chip (including the drain chip) is placed at the beginning of the cutting of the tooth, and then this chip rises up along the helical teeth (or both the same along helical chip grooves) and is simultaneously discarded from the mill by inertia, since the chip has weight and mass. This occurs when milling ledges, planes, wide and shallow grooves. But when milling narrow and deep grooves, the chips cannot be removed in this way (since the entire space is closed), therefore, in this case, the chips must be removed under pressure from the coolant or compressed air.

Drain chips are a common type of chip in the processing of viscous and sometimes non-viscous metals. This shavings has the form of a continuous tape, which, when faced with an obstacle, does not collapse, but twists, clings to any protrusions and is difficult to remove from the cutting zone under pressure with coolant or compressed air (unless grinded into small parts).

Note that other types of shavings, which are not in the form of a continuous tape, but scatter into separate fragments, are also difficult to evacuate from a narrow and deep groove, since these fragments are not small enough to be washed out under pressure, coolant, or compressed air.

Note that the resource of the cutter can be evaluated by many criteria, for example, the wear criterion, but in this case it is evaluated by the criterion for the failure of the cutter.

Breakage of the cutter is an unplanned (emergency) failure of the tool as a result of improper operation (for example, as a result of clogging of chip grooves). Unlike milling cutter wear, which can be calculated or experimentally determined even with factors such as secondary chip cutting

The roughness and cleanliness of the machined surface is formed by the main teeth, which extend from the end plane to the shank, the additional teeth help the main teeth in the work of cutting, and in the utility model, the additional teeth also have chip breakers, which also chop the chip, which contributes to its removal from the zone cutting.

Shavings from the part of the teeth that are located above the end part (when the cutter is vertical) have a significantly larger chip groove and are mainly transported upward due to the presence of helical teeth (helical chip grooves also correspond to helical teeth). The lower parts of the main teeth and the additional teeth are more susceptible to grinding, and the additional teeth have chipbreakers for grinding chips.

The disadvantage of the prototype is eliminated as follows.

To ensure the absence of chip shavings on the additional teeth of the utility model, chip breakers are made, which are chip separation grooves; between the chip separating grooves are the teeth, which, in combination with the chip separating grooves, are called chipbreakers. Chipbreakers crush (grind) the chips at the end face of the cutter into small parts, which makes it possible to remove it with compressed air or pressurized coolant and ensures satisfactory operation of the cutter.

Here you need some information about chipbreakers.

The chipbreakers are a plurality of chip separating grooves located on the tooth, located a short distance from each other on the tooth.

Chip separating grooves are narrow grooves cut across the cutting teeth or what is the same across the cutting blades; a cutting blade is a sharpened, sharpened portion of a cutting tooth.

Note that in the technical literature, operating instructions and advertising sites, the concepts of “chip flutes, teeth with chip breakers, chip breakers” for end mills are identical, that is, they mean the same thing.

Traditionally, the cutting blade of a tooth cutter has a straightforward appearance. If on these teeth (more precisely, on the blades of these teeth) to perform chip separation grooves, then between the chip separation grooves on the teeth will remain teeth. The width of these teeth is what remains of the rectilinear blade, that is, only sections from the rectilinear blade remain.

The chipbreakers on the tooth are small teeth (the teeth are part of a straight tooth in size equal to the distance between the chip separating grooves) on the teeth; the width of the tooth and the distance between the teeth are approximately the same (or comparable). The shape of the teeth is different, the geometric shape of the depressions (distances) between the teeth, that is, chip separation grooves) is also different, including the simplest rectangular one, which is presented in this proposed utility model.

Note that in the chip breakers of standard end mills, the chip separating grooves are located on all the teeth along the entire length of the working part of the milling cutter.

In the proposed utility model in FIG. 4, the additional cutting teeth depict chip cutting grooves for general use, i.e., traditional rectangular chip cutting grooves. Each type of chip separation groove has its own advantages and disadvantages. The advantage of rectangular chip-cutting grooves is that they are the easiest to manufacture (compared, for example, with trapezoidal) and are general-purpose chip-cutting grooves for milling parts of general mechanical engineering; such most common parts include body parts of various mechanisms, brackets, traverses.

Rectangular chip-cutting grooves are made with a conventional flat grinding wheel and this wheel does not require preliminary straightening along the profile.

We also note the following. The chip separation grooves appeared a long time ago, before there was one or two chip separation grooves on the entire tooth; but still they were called chipbreakers. In the XXL Engineering Encyclopedia, in the Equipment, Materials Science, and Mechanics section on page 256, chip cutting grooves are called chip breaking grooves, namely, “they are equipped with chip cutting (chip breaking) grooves that are placed on the teeth”. In GOST 24637-81 on page 6, chip cutting grooves are called chipbreakers, namely, “depth of the chipbreaker cavity”.

The chipbreakers are made only on additional teeth and this does not affect the roughness and cleanliness of the treated surface. The surface to be machined is formed by the main teeth, the length of which is from the end plane to the shank, and the additional teeth grind (grind) the chips into small parts.

It should also be emphasized that additional teeth (of shorter length) help in the work of cutting in the end part and therefore increase the resistance of the cutter as a whole.

The purpose of the proposed utility model is to grind the chips in the end part of the cutter into small parts in order to be able to remove it from the end zone of the cutting with coolant under pressure or compressed air and thereby create conditions for the absence of chip filling and breakage of the cutter.

The design of the end mill according to the proposed utility model is new, not known in the art, has a novelty criterion and corresponds to an inventive step.

An essential feature is that on each additional tooth of the prototype there are chip separating grooves, which, in combination with the teeth located between them, form a chipbreaker for grinding in the end part obtained by milling the chip into small parts with the possibility of removing these small particles with compressed air or under pressure coolant, and the chip separating grooves and teeth of each additional tooth are located along the helical line at the same, respectively, distance from the torus core plane and begin at a distance of 0.9 mm from the end plane, and the chip separation grooves themselves are rectangular in shape with a width of 0.6 mm and a depth of 0.45 mm, the width of the teeth is 0.6 mm, while the chip breaker pitch is 1.2 mm ( this is essentially the distinguishing part of the proposed utility model formula).

Here it is necessary to state some concretization. In the “Essential feature” it is stated “... a chipbreaker for grinding in the end part obtained when milling chips into small parts ...”. In the end part of the mill there are additional teeth having chipbreakers, and some of the main teeth that do not have chipbreakers. Chips from additional teeth are already crushed into small parts. Shavings from the main teeth are in the form of a continuous tape or large fragments. This ribbon shavings or large fragments are also crushed into small pieces in the closed area of the groove with additional chip breakers. Therefore, in the “Essential feature” the concept of “... for grinding in the end part obtained by milling the chips into small parts ...” refers to all the teeth of the end part (additional and main within the end part).

There is an analogue of the proposed utility model. The ISKAR end mills have a FINISHRED family of four-tooth milling cutters. In these cutters, two opposing teeth are equipped with chip separating grooves (chip breakers), which makes their surface serrated. Two other teeth of chipbreakers do not have. Thus, it is possible to produce roughing (with teeth with chip breakers) and finishing (with teeth without chip breakers) milling with one cutter. ”In these cutters, chip breakers (as teeth with chip breakers are called in some cases) during roughing, chip from all the cutter teeth is crushed, which ensures normal chip evacuation. We emphasize that traditionally in end mills with chipbreakers, the protrusions and depressions are offset along the helix when counting from the end plane for each subsequent tooth, so that each subsequent tooth cuts off that part of the metal that remained uncut by the previous tooth.

In the design of the proposed utility model, the uncut part of the metal with an additional tooth, is cut off with the main tooth due to the presence of chip separation grooves. If the chip separating grooves and teeth of each additional tooth in the utility model are located along the helical line at a correspondingly unequal distance (with an offset equal to the chip breaker step) from the end plane, then at the end plane we will have different parts of the crushed chips, which will degrade the quality chipbreaker work.

Objectively manifesting technical consists in grinding in the end part of the cutter into small parts with the possibility of their removal under pressure from a cooling liquid or compressed air. This objectivity is manifested in the following. If the prototype mills a narrow and deep groove, and then slowly (so as not to damage the surface to be machined), remove the cutter from the groove, then we will see on the teeth in the end part of the cutter (most distinctly when draining chips, that is, with chips that look like a continuous tape, not breaks when meeting with a solid obstacle, and curls) shavings wound on the teeth, which can be seen visually. When milling with the proposed utility model, this is not present on the teeth, since instead of chips there are small pieces, and there is nothing to wind onto the teeth.

The proposed utility model has the property of industrial applicability, since it does not require any special equipment for its manufacture.

A brief description of the drawings.

The proposed utility model is shown in FIG. 1-4, on which:

in FIG. 1 shows a front view of an end mill;

in FIG. 2 (section AA) shows a section of that part of the mill where there are cutting teeth extending from the end plane to the shank and cutting teeth of smaller length;

in FIG. 3 (section BB) shows a section of that part of the cutter where the cutting teeth have a length from the end plane to the shank;

in FIG. 4 shows an additional cutting tooth (of shorter length) with chip separating grooves, which in combination with the teeth between them form a chipbreaker;

in FIG. 5 shows the relative position of the cutter according to the proposed utility model and the part when processing a narrow deep groove.

Utility Model Implementation

The end mill (Fig. 1-4), contains a shank 1, a body 2, an axis (center line) 3, an end plane 4 located perpendicular to the axis, the main helical cutting teeth 5, resting on the back of the head 6, and additional helical cutting teeth 7, based on the nape 8 located on the body, the main helical teeth with the nape having a length H from the end plane to the shank, and the additional helical teeth with the nape having a length C equal to 30% of the length of the main teeth when counting from the end plane; the number of additional teeth is equal to the number of main teeth. On each additional tooth, there are chip separation grooves 9, which, in combination with the teeth 10 located between them, form a chipbreaker for grinding in the end part the chips obtained when milling into small parts with the aim of removing these small particles with compressed air or pressurized coolant, and chip cutting grooves each additional tooth are located along a helical line at the same, respectively, distance from the end plane and begin at a distance L = 0.9 mm from the end plane, taking into account the regrinding of the teeth during blunting, and the chip separating grooves themselves are rectangular in shape with a width of K = 0.6 mm and a depth of h = 0.45 mm, taking into account edits during blunting, the width of the teeth is n = 0.6 mm, taking into account their strength while the chipbreaker pitch is equal to P = 1.2 mm

In FIG. 4 for the simplest form of chip separation grooves used - rectangular chip separation grooves, these grooves and teeth are shown between them (chip separation grooves, which, in combination with the teeth located between them, form a chipbreaker). For each additional tooth, each groove is, respectively, at the same distance from the end plane.

In FIG. Figure 5 shows the relative position of the cutter and the deep and narrow groove, which is typical and most difficult for machining a complex profile surface.

The end part of the cutter is the part of the cutter with a length equal to the length of the additional teeth when counting from the end plane.

Chip separating grooves are narrow grooves cut across the cutting teeth or what is the same across the cutting blades; a cutting blade is a pointed, sharpened portion of a cutting tooth.

Chip groove is the space between the teeth and the back of the head; in more detail, this is the space between a specific tooth and the nape of an adjacent tooth.

The end mill has helical teeth. The helical teeth along the screw flutes corresponding to these teeth raise the chips up from the end cutting zone, that is, the helical teeth are a kind of conveyor. At the same time, the chip has a mass and when the mill rotates due to inertia forces, the chip flies away from the mill. Chip rises from the end part with helical flute grooves (helical teeth), and is discarded from the milling cutter when there is a space where the chip could fly off. For example, when milling ledges or open planes.

When milling deep and narrow grooves, there is no such space; everything is closed by the walls of the groove.

The proposed utility model for milling complex surfaces with the presence of narrow and deep grooves works as follows. On additional teeth of the utility model, there are chipbreakers, which are chip separating grooves with a step equal to twice the width of these grooves; between the chip separating grooves are the teeth, which, in combination with the chip separating grooves, are called chipbreakers. Chipbreakers crush (grind) the chips at the end face of the cutter (including the chips from the main teeth) into small pieces, which helps to facilitate its removal with compressed air or under pressure.

In FIG. 1-4 presents the end mill of the proposed utility model.

Complex surfaces is a general constructive concept that includes various configurations of machined surfaces. But a more detailed and substantive examination of the working principle of the utility model is advisable to consider the processing of a deep and narrow groove in Fig. 5.

Note that a typical element of a complex profile surface, the most difficult for milling due to insufficient chip removal, is a narrow and deep groove.

In FIG. 5 shows the relative position of the cutter according to the proposed utility model and the part when processing a narrow deep groove. The width of the groove is approximately equal to the diameter of the cutter, the depth of the groove is approximately equal to the entire length of the cutting part of the cutter from the end plane to the shank. The shavings here are not able to fly away from the cutter due to inertia forces, since there is no space for this that is blocked by the walls of the groove and the shavings abut against these walls. This is especially pronounced in the area near the end of the cutter with the vertical position of the cutter.

In this case, the chips must be removed under pressure from the coolant or compressed air. But the chips, especially when milling viscous metals in the presence of discharge chips, with their sharp edges clings to all the protrusions, it is very difficult to remove under pressure with coolant or compressed air. So that such shavings can be removed, it must be crushed into small pieces.

In a narrow and deep groove, the chips cannot be removed due to inertia forces, therefore, other types of chips, such as break chips or articular chips, which consist of separate fragments, but not small enough, also have difficulty removing chips.

Narrow and deep grooves are the most difficult and typical sections of a complex machined surface for milling; in working drawings, narrow and deep grooves are often called pockets, wells, crevices, and indentations.

In the utility model, additional teeth help in cutting the main teeth, and chip breakers (small teeth) on the additional teeth grind (grind) the chips in the end part of the cutter (including the main teeth in the end part) into small parts, which helps to facilitate its removal from chip grooves with compressed air or pressurized coolant.

Chipbreakers on the teeth here play a decisive role in chip control, allowing the cutter to operate in normal mode without filling the chips, providing the required resource for the cutter under the condition that there is no breakage of the teeth.

Chipbreakers crush the chips at the end of the cutter in the end plane on the additional teeth. That is, where the possibility of filling chips and breaking the cutter is most dangerous.

The fact that the chips are not refilled, but crushed into small parts can be observed visually, see the objectively manifest technical result. In the area of the main teeth outside the end part of the cutter towards the shank, the number of teeth is smaller, the size of the chip groove is larger and sufficient to transport the chips (towards the shank) and the chip does not fill in the chip groove.

The work of the milling cutter according to the proposed model consists in the fact that the main teeth perform the main cutting work, and the additional teeth help the main teeth in the most difficult for the cutting end part of the cutter. In the proposed utility model, additional teeth have chip breakers (small teeth), therefore, these teeth correspond to small, crushed chips during milling, with the aim of making it easier to remove from the end zone of cutting.

When milling ledges, wide and shallow grooves, a useful model, having chip breakers on additional teeth, is more productive, since the teeth with chip breakers have less cutting force.

The utility model was tested under production conditions in a mechanical workshop. A milled part made of steel of the grade 35 HB 120-140 steel, GOST 4543-71, unstrengthened and had a discharge chip. The diameter of the cutter is F40mm, the length of the main teeth is H = 30 mm, the length of the additional teeth is C = 9 mm. The check was carried out by a milling cutter with rectangular chip-cutting grooves made with a groove width n = 0.6 mm, a depth h = 0.45 mm, a tooth width K = 0.6 mm, and a value L = 1.2. At first, a deep narrow groove of large length and half open was milled, that is, on one side the cutter exited the groove and the chips could be visually inspected and checked. The check was carried out on the condition of the presence of grinding chips into small pieces. At the exit from the groove, the chip with the accepted parameters of the chip guide had a crushed shape and conditions for filling the cutter occurred. The value of L = 1.2 is sufficient as a reserve for regrinding of teeth during blunting at the end. The value of h is sufficient for dressing chip separation grooves when blunting on the rear surface. Chipping teeth did not occur.

Then a closed and deep groove was milled and the chips were blown out with compressed air.

When milling a closed narrow and closed groove, small particles of shavings were removed from the groove with compressed air and no chip shavings occurred.

Above the end part of the mill, the discharge chips from the milled metal of steel grade 35 along helical grooves, which are two times larger in volume (than in the end part), rises up (with the vertical position of the mill) and leaves the milling zone.

When the milling cutter is used for about one hour, the teeth become dull and the teeth are regrind and the chip cutting grooves are straightened.

Bibliography

1. An article in the journal STIN (Machine Tools and Instruments) 2013, No. 9. “An analysis of the temperature fields of the end mill with equal resistance of the side and end cutting blades when milling hard-to-work steels. Authors of the article Cherkashin V.P., Vodilov A.V.

2. RU 2392095 C1 End mill.

3. RU 2394670 C1 End mill with torsional rigidity.

4. RU 2507038 C1 End Mill for Processing Hard Materials.

5. RU 1537414 C1 End Mill.

6. RU 2568231 C1 End mill for processing laminated plastics.

7. RU 2573858 C1 Combined end mill.

8. Utility model No. 125502 V23C. End Mill High Strength. Authors Cherkashin V.P., Vodilov A.V.

9. Utility model No. 153802 V23C. The combined end mill of the increased durability. Authors Cherkashin V.P., Vodilov A.V.

10. Utility model No. 158628 V23C. End mill with interchangeable cutting inserts with increased resistance. Authors Cherkashin V.P., Vodilov A.V.

11. US patent US 6231275 B1.

12. US patent US 6439811 B1.

13. GOST 20534-75 End mills with a tapered shank, equipped with carbide crowns.

14. GOST 20538-75 Elongated end mills with a diameter of 10 to 50 mm with a tapered shank, equipped with screw carbide inserts.

15. GOST 24637-81 End mills equipped with screw carbide inserts for machining parts of high-strength steels and titanium alloys on programmed machines. Technical conditions

Claims (1)

An end mill comprising a shank, a body, an axis, an end plane located perpendicular to the axis, an equal number of main helical cutting teeth resting on the nape, and additional helical cutting teeth resting on the nape located on the body, the main helical teeth with nape are extended from the end plane to the shank, and additional helical teeth with nappes have a length from the end plane of 30% of the length of the main teeth, characterized in that the additional helical the cutting teeth are made with chip separating grooves and with the teeth located between them to form a chip breaker for grinding in the end part of the chips obtained during milling, while the chip separating grooves of each additional helical cutting tooth are located along a helical line at a distance of 0.9 mm from the end plane and are made rectangular 0.6 mm wide and 0.45 mm deep, the teeth are 0.6 mm wide, and the chipbreaker pitch is 1.2 mm.

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