WO2007025679A1

WO2007025679A1 - Tool for machining workpieces

Info

Publication number: WO2007025679A1
Application number: PCT/EP2006/008348
Authority: WO
Inventors: Dieter Kress; Friedrich Häberle
Original assignee: MAPAL Fabrik für Präzisionswerkzeuge Dr. Kress KG
Priority date: 2005-08-29
Filing date: 2006-08-25
Publication date: 2007-03-08
Also published as: DE102005041331A1

Abstract

The invention relates to a tool for machining workpieces, comprising at least one geometrically defined blade, a shaft (3) having a front surface (11), a head (5) which comprises a bearing surface (17) and a front surface (23) and which is secured to the shaft (3). The bearing surface (17) is arranged on the front surface (11), the front surface (11) of the shaft (3) comprises a first structure (15), the head (5), on the bearing surface (17) thereof which is oriented towards the front surface (11), comprises a second structure (19). The structure is embodied in such a manner that it engages in another structure in such a manner that torque introduced into the shaft (3) is transferred to the head (5). Said tool is characterised in that the head (5) can be soldered to the shaft (3), the head (5) comprises a hard material layer (21) on the front side thereof (23), and that at least parts of the geometrically defined blade are worked produced from the hard material layer (21).

Description

Tool for machining workpieces

description

The invention relates to a tool for machining workpieces according to the preamble of claim 1 and a method for producing a tool for machining workpieces according to the preamble of claim 21.

Tools and methods of the type discussed here are known. In particular, in the machining of holes in workpieces made of hardened materials or cast materials or non-ferrous metals (non-ferrous metals) tools are used, which are equipped with blades made of polycrystalline boron nitride (PKB) or polycrystalline diamond (PCD). The cutting edges are inserted into the basic body of the tools and soldered into suitable grooves. For manufacturing reasons, it is not possible to realize tools whose diameter is smaller than about 6 mm. The production of such tools is possible only with considerable effort. In particular, the soldering of blanks, so primitives, for the production of cutting, is very problematic because all blanks of a tool must be soldered at the same time. The shaft is too small, as that individual lots could be brought separately to soldering temperature. In the dimensions of the type mentioned here, the entire tool is so hot that already soldered blanks would solve when soldering more blanks again. In addition, the soldering surface available for fastening the cutting edges is so small with such small tool diameters that the cutting edges in the tool hold relatively poorly or only little bear in the tooling. workers. The smaller the diameter of the tool, the smaller the hold of the cutting edges.

It is therefore an object of the invention to provide a tool for machining workpieces which comprises geometrically defined cutting edges of polycrystalline boron nitride or of polycrystalline diamond and in this case has a diameter which is significantly smaller than 6 mm, for example in a range of 1, 5 mm to 4 mm, in particular from 2 mm to 3 mm.

To solve this problem, a tool is proposed which has the features mentioned in claim 1. It is characterized by a head attached to a shaft, which is fastened by means of a soldering process and has a hard material layer in the region of its end face, in the region of which at least parts of the geometrically defined cutting edge are provided. The fact that said head of the tool is provided with a hard material layer, in the area of which the cutting edges of the tool are realized, it is no longer necessary to use individual cutting polycrystalline boron nitride or polycrystalline diamond in the tool. Since the hard material layer extends over a larger area of the head, it is very well connected to the head so that the geometrically defined cutting edges provided in the area of the hard material layer can absorb high cutting forces.

Further embodiments emerge from the subclaims.

The object of the invention is also to provide a method by means of which tools for machining workpieces can be produced which do not have the abovementioned disadvantages. To solve this problem, a method with the features of claim 21 is proposed, in which a head is soldered to a shank of a tool. In this case, the head, preferably before attachment to the shaft, provided with a hard material layer. At least in this at least one groove is introduced to realize at least one geometrically defined cutting edge. It is therefore essential that after placing the head on the shank of the tool a hard material layer is ready, in which at least one cutting edge can be incorporated. It is therefore no longer necessary to solder individual cutting into the tool.

Embodiments of the method emerge from the subclaims.

The invention will be explained in more detail below with reference to the drawing. Show it:

Figure 1 is a schematic diagram of a blank of a tool in

Exploded view;

Figure 2 is a perspective bottom view of a head of the blank according to Figure 1 and

Figure 3 is a perspective view of a finished tool.

The blank of a tool 1 shown in FIG. 1 comprises a shaft 3 and a head 5 arranged here in an exploded view at a distance from the shaft. In the exemplary embodiment shown here, the shaft 3 is essentially cylindrical and has a uniform length over the length shown here Outside diameter on. The head 5 facing away from the end 7 of the Shaft 3 is broken off, so that its design is not recognizable here. It should be noted here that this end 7 have a larger outer diameter and may be specially designed to allow the inclusion in a machine tool or in an intermediate piece, an adapter or the like.

At the head 5 facing the end 9 of the shaft 3, an end face 11 is provided which lies in an imaginary plane on which the central axis 13 of the tool 1 is perpendicular. It should be noted here that the tool 1 is usually set in rotation during the machining of workpieces and thus rotates about the central axis 13, while it is brought into engagement with a workpiece to be machined. In principle, however, it is also possible to hold the tool 1 and to set the workpiece in rotation. Decisive is a relative rotation between tool 1 and workpiece.

The schematic diagram shows that a first structure 15 is introduced into the end face 11, in this case at least one V-shaped groove extending over the entire cross section of the end face 11 and extending along an imaginary diameter line, that is to say the center axis 13 cuts.

The head 5 is provided on its the shaft 3 and thus the end face 11 facing abutment surface 17 with a second structure 19 which engages in the first structure 15. As a result, an introduced into the shaft 3 torque on the head 5 can be transferred.

On the opposite side of the contact surface 17 of the head 5 is provided with a hard material layer 21 whose thickness to the later Embodiment of the head 5 is adjusted. Preferably, the hard material layer 21 extends over the whole, the contact surface 17 opposite end face 23 of the head 5. In principle, however, a hard ring on the end face 21 can be applied, whose diameter is adapted to the subsequent use of the head 5.

In the illustrated here, preferred embodiment of the tool 1, the end face 23 is arranged in an imaginary plane on which the central axis 13 is perpendicular. Since the contact surface 17 is located in an imaginary plane on which the central axis 13 is perpendicular, the end face 23 extends parallel to the contact surface 17. Since the hard material layer 21 is formed here with a uniform continuous thickness, the surface 25 is also in an imaginary plane arranged on which the central axis 13 is vertical.

The tool 1 is characterized in that the head 5 is soldered onto the shaft 3. The distance between the contact surface 17 and the hard material layer 21, ie the length of the head 5 measured in the direction of the central axis 13, can be selected such that the contact area between the contact surface 17 of the head 5 and the end surface 11 of the shaft 3 during the soldering process Heat does not damage the hard material layer 21.

FIG. 2 shows a perspective bottom view of the head 5 of the tool 1 according to FIG. 1. Identical parts are provided with the same reference numerals, so that reference is made to the preceding description in order to avoid repetition. In the representation selected here, the head 5 is opposite to that in FIG 1 chosen significantly enlarged. He is also essentially cylindrical.

It can be seen that a second structure 19 having at least one elevation is realized on the contact surface 17 of the head 5 facing the observer. This is chosen so that it can engage in a first structure 15 on the end face 11 of the shaft 3.

Ultimately, it is irrelevant how the first structure 15 and the second structure 17 and whether elevations and / or elevations are formed on the end surface 11 and elevations and / or depressions correspondingly on the contact surface 17, provided that it is ensured that of the shaft 3, a torque can be transmitted to the head 5. It should be noted that the tool 1 described here is also realized with very small diameters, ie that the structures on the one hand on the end face 11, on the other hand on the contact surface 17 are very small. Therefore, these are preferably produced by means of non-cutting processes, for example by laser or erosion processes, wherein elevations of the structures are preferably produced by die erosion and depressions, preferably by wire erosion.

In the embodiment shown here, a second structure 19 is realized on the contact surface 17 of the head 5, which comprises two running along imaginary diameter lines, mutually perpendicular ribs 27 and 29, whose cross-section is triangular or V-shaped. Other cross-sectional shapes are also possible. They do not have to be selected identically as the cross-sectional shape of the ribs 27, 29 absorb- The grooves of the first structure 15. They only have to be suitable to intervene in the grooves with as little play as possible.

The mutually perpendicular ribs 27 and 29 thus engage in correspondingly arranged, the first structure 15 representing depressions in the end face 11 of the shaft 3 a. They cause because of the arrangement chosen here a centering of the head 5 on the shaft 3, so that the connection between the head 5 and shaft 3 can be realized in a simple manner: It requires no special means to center the two parts during the connection process. If two mutually perpendicular grooves are provided on the end face 11 of the shaft 3, one of which can be seen in Figure 1, it is basically sufficient to provide on the contact surface 17 of the head 5 projections, preferably because of the centering at least three, in the engage the first structure 15 forming gutters. A maximum torque can, however, be transmitted if, as shown in FIG. 2, for the implementation of the second structure 19, grooves 27 and 29 running perpendicular to one another over the diameter of the contact surface 17 are provided, which run into corresponding grooves of the first structure 15 engage on the end face 11.

It is particularly preferred to form the first and second structures complementary, because this results in the largest contact surfaces and the possibility of transmitting a maximum torque.

From the explanations it is clear that for the centering of the two parts of the tool 1 also three star-shaped grooves or projections can be provided. The Type of configuration of the structures 15 and 19 is thus selectable within a wide range and adaptable to desired conditions.

Figure 1 shows a tool 1 before the introduction of special external structures, ie a blank. If the head 5 is soldered to the shaft 3, according to FIG. 1, a continuously cylindrical tool 1 is formed, which has a uniform outer diameter over the length visible here, that is to say passes smoothly from the shaft 3 to the head 5.

To produce the finished tool 1, at least one groove N can be introduced into the peripheral surface of the blank, that is to say into the circumferential surface U1 of the head 5 and optionally the peripheral surface U2 of the shaft 3. This should extend at least over the thickness of the hard material layer 21 in order to form a geometrically defined cutting edge here. As is usual with known tools, with respect to the cutting edge produced in this way, a groove N, designed as a chip groove, is provided as seen in the direction of rotation of the tool 1. This extends at least over the region of the active cutting edge, ie the cutting edge, which engages with a workpiece to be machined. Preferably, however, it is provided that the cutting edge and the groove N extend not only over the thickness of the hard material layer but at least over the length of the head 5 and preferably also extend into the shaft 3.

The at least one groove N serving to produce the at least one cutting edge is preferably arranged in the peripheral surface of the tool 1 such that it does not damage the first structure 5 and the second structure 19. It is therefore preferably on it ensured that an introduced into the peripheral surface of the tool 1 groove intersects neither one of the ribs 27 nor one of the recesses in the end face 11 of the shaft 3. As a result, the structures remain over the entire diameter of the tool 1 and can transmit a maximum torque.

The at least one groove N, which extends in the peripheral surface of the tool 1 at least over the thickness of the hard material layer 1 measured in the direction of the longitudinal axis 13, can run parallel to the central axis 13 or along an imaginary screw line which runs concentrically to the central axis 13 ,

So it is very possible to realize the tool 1 as a milling cutter, drill, reamer or the like.

It is particularly advantageous that the hard material layer 21 has a large contact surface on the front side 23 of the head 5, that is to say it can absorb large forces. In this case, it is relatively easy to machine the hard material layer 21 in order to realize desired cutting edges, which can also extend into the upper side 25 of the hard material layer 21. It becomes clear that during the production of the cutting no soldering is necessary. Only the head 5 needs to be soldered onto the shank 3 to make the blank of the tool 1, which can then be machined in a suitable cutting or non-cutting manner to produce cutting, chip grooves, and other desired geometries. Preferably, the hard material layer 21 is applied to the end face 23 of the head 5, before it is soldered to the shaft 3. This prevents that the solder joint between the head 5 and shaft 3 is damaged by the application of the hard material layer. It is clear that even with tools with a very small diameter of the head 5 is relatively easy to handle, especially as measured in the direction of the central axis 13 length is variable and adaptable to different applications.

Already the representation according to FIG. 1 reveals that the use of separate cutting edges in the peripheral surface of the tool 1 by means of a soldering process is very complicated, practically impossible, especially when very small outside diameters of the tool 1 are realized.

The explanations of Figures 1 and 2 also show that the method of manufacturing the tool 1 is very simple. It only requires the realization of a first structure 15 on the end face 11 of the shaft 3 and a second structure 19 on the contact surface 17 of the head 5 in order to transmit a torque from the shaft 3 to the head 5 easily. Preferably, the structures 15 and 19 are formed so that the head 5 automatically centered on the shaft 3, while it is soldered to the shaft.

The application of the hard material layer 21 on the end face 23 of the head 5 is possible in a simple, known manner. Preferably, a polycrystalline boron nitride (PKB) layer or a polycrystalline diamond (PCD) layer is realized here.

The head 5 can be cut out of a basic element, also referred to as a blank, preferably in a non-cutting process, in particular by means of a laser or by means of wire erosion. It is very possible to realize a peripheral surface 111 of the head 5, which deviates from the cylindrical surface shown in Figure 1, and already more or less corresponds to the desired outer contour of the finished tool 1. Here, only one grinding operation of the head 5 is required, in order in particular to configure its hard material layer 21 in such a way that desired cutting edges are realized here. Preferably, the outer contour of the head 5 is the same over its entire length. The specification of a certain outer contour of the head 5 prior to soldering on the shaft 3 is particularly useful if a PCD layer is selected for the hard material layer 21, the processing is time-consuming and expensive due to the particular hardness. If the outer contour of the finished tool is already predetermined at least in the region of the head 5, only slight grinding work is required to complete the tool 1 or the at least one cutting edge in the region of the hard material layer 21.

A finished tool 1 is shown in FIG. It has a shaft 3 and a head 5, which is soldered here on the end face 11 of the shaft 3, so that its contact surface 17 abuts seamlessly against the end face 11.

At the upper side 25 of the head 5 facing away from the shaft 3, the hard material layer 21 is provided.

In the illustration according to FIG. 3, a complete tool 1 is shown. By way of example, the shaft 3 here transitions into a fastening region 31 which has a larger outer diameter than the shaft 3 and is adapted to the receptacle of a machine tool, an adapter, an intermediate piece or the like is so that the tool 1 can be easily attached. The blank of the tool 1 may have before working out the contour of the shaft 3 and the head 5 over its entire length a constant diameter and a uniform outer contour.

In the exemplary embodiment of the tool 1 illustrated here, the outer contour of the head 5 continues in the shaft 3, so that chip grooves provided in the region of the circumferential surface U1 of the head 5 continue to run without any projections in the area of the peripheral surface U2 of the shaft 3.

After all, it turns out that the tool 1 is very simple and easy to produce. Preferably, at least the head is made of hard metal. The shaft can be made of carbide or steel. The hard material layer 21 preferably consists of PKB or PKD.

The production of the desired cutting edges and contours in the area of the hard material layer 21 and / or the head 5 and / or the shaft 3 is possible in a conventional manner. It therefore requires no special measures, the cutting geometry, the shape of the chip spaces, chip and clearance angle and gates and other functional surfaces that are needed depending on the type of tool to realize the tool 1.

It turns out that the hard material layer 21 preferably rests over its entire surface on the end face 23 of the head 5 and thus is firmly connected to this and can absorb high forces. In particular, it is relatively easy, even with very small diameters of the tool 1, the head 5 with the hard material layer 21 on the shaft 3 festzulö- and then to realize the desired cutting edges and other geometries.

If, as explained above, the head and thus the hard material layer 21 already realized in a desired contour, possibly also the shaft 3, the final grinding process for the completion of the tool 10 after soldering between the head 5 and shaft 3 is reduced to a minimum.

The hard material layer 21 can also be formed annularly, at least if only in the peripheral region of the head 5 cutting are to be provided, and in particular when the tool has a coolant supply, which opens into the end face 23 of the head 5.

From the explanations of the tool 1 and the method of manufacturing such a tool, the following becomes clear:

The tool 1 is very simple, so that its production is inexpensive feasible. It turns out that only on the front side 23 of the head 5 a hard material layer 21 is required and this only in the area of the contact surface U of the head 5 of the tool 1. It is relatively easy to apply to the end face 23, this hard material layer 21, either a quasi-continuous disc forms on the end face 23, or a ring which extends along the peripheral surface U1 of the head 5.

In the blank of the tool 1 which can be seen from FIG. 1, at least one, preferably a plurality of grooves are made in its peripheral surface, that is, in the peripheral surface U1 of the head 5 and in the peripheral surface U2 of the shaft 3. cut material layer 21. The contour of the at least one groove N is selected so that a side edge of the groove forms a cutting edge of the tool 1. Thus, if several grooves are introduced into the tool 1, this has correspondingly more cutting edges.

Because the groove intersects the hard material layer 21, the groove N passing through the end face 23 and the hard material layer 21 forms a cutting edge in the hard material layer. In this case, this groove N also forms a cutting edge in the head 5 and possibly also in the shaft 3. It should be noted, however, that the thickness of the hard material layer 21 defines the length of the particularly resistant cutting edge of the tool 1. The thickness of the hard material layer 21 is thus selected so that the particularly stressed areas of the cutting edge run in this hard material layer.

It thus turns out that the hard material layer 21 is relatively easy to apply to the end face 23 and its thickness defines the length of the region of the cutting edge which is particularly resistant.

Further areas of the head 5 and the shaft 3 require no coating with hard material, which significantly reduces the cost of manufacturing the tool.

If the hard material layer 21 is formed as a ring, measured in the direction of the central axis 13 of the tool 1 width of the ring must be chosen so that this width is chosen so large that when introducing a groove in the peripheral surface LH, then just the Hard material ring cuts, sufficient material is available to form a cutting edge. Preferably, the width of the ring is made greater than or equal to the depth of the groove N. Particularly preferred is a tool 1, wherein the width of the hard material ring is selected so that it is at least slightly larger than the depth of the groove. Thus, when introducing the groove, not only a cutting edge on the head 5 is produced, but also a chip removal region of particularly resistant material, which extends to the bottom of the groove.

Claims

claims

1. Tool for machining workpieces with at least one geometrically defined cutting edge, with a one end face (11) having shank (3), with a on the shaft (3) fixed, a contact surface (17) and an end face (23) having head (5), wherein the contact surface (17) rests against the end surface (11), the end surface (11) of the shaft (3) has a first structure (15), the head (5) on its contact surface facing the end surface (11) (17) comprises a second structure (19), wherein one structure is adapted to engage the other structure such that a torque introduced into the shaft (3) is transferable to the head (5), characterized in that the head (5) can be soldered onto the shaft (3), the head (5) has a hard material layer (21) on its end face (23), and at least parts of the geometrically defined cutting edge are machined out of the hard material layer (21).

2. Tool according to claim 1, characterized in that only the end face (23) is provided with a hard material layer (21).

3. Tool according to claim 1 or 2, characterized in that the thickness of the hard material layer (21) corresponds to the length of the cutting edge.

4. Tool according to one of the preceding claims, characterized in that the hard material layer (21) is formed as a ring whose outer diameter corresponds to the outer diameter of the tool (1).

5. Tool according to claim 4, characterized in that the width of the ring is greater than or equal to the depth of the groove (N).

6. Tool according to one of the preceding claims, characterized in that the first structure (15) and the second structure (19) are formed so that the head (5) on the shaft (3) is centered.

7. Tool according to one of the preceding claims, characterized in that the first or second structure (15,19) at least one recess and the second or first structure (19,15) has at least one increase.

8. Tool according to claim 7, characterized in that the recess is formed as a groove.

9. Tool according to claim 8, characterized in that at least three star-shaped to the central axis (13) of the tool (1) extending grooves are provided.

10. Tool according to claim 8, characterized in that two are each provided along a diameter line extending, an angle enclosing grooves are provided.

11. Tool according to one of claims 7 to 10, character- ized in that the increase is punctiform.

12. Tool according to one of claims 7 to 10, characterized in that the increase is designed as a rib (27,29).

13. Tool according to claim 12, characterized in that two respective extending along a diameter line, each other with an angle enclosing ribs (27,29) are provided.

14. Tool according to claim 12, characterized in that at least three star-shaped standing ribs are provided.

15. Tool according to one of the preceding claims, characterized in that the first and second structures (15,19) are complementary.

16. Tool according to one of the preceding claims, characterized by at least one in the peripheral surface (U1, U2) of the tool (1) introduced groove (N).

17. Tool according to claim 16, characterized in that extending the at least one groove (N) over the peripheral surface of both the head (5) and the shaft (3).

18. Tool according to claim 16 or 17, characterized in that the groove (N) extends in a straight line or along an imaginary helix.

19. Tool according to one of the preceding claims, characterized in that the outer diameter of at least the head (5) 6 mm, preferably 1, 5 mm to 4 mm, in particular 2 mm to 3 mm.

20. Tool according to one of the preceding claims, characterized in that the hard material layer (21) comprises PKB and / or PCD.

21. A method for producing a tool for machining workpieces with a front surface having a shaft and a contact surface having head, in particular according to one of claims 1 to 16, characterized in that on the end face (11) of the shaft (3) a first structure (15) and on the abutment surface (17) of the head (5) a second structure (19) is formed, wherein the one structure is designed so that it engages in the other for transmitting a torque that the head (5 ) is placed on the end face (11) of the shaft (3) and soldered, that the head (5) on its end face (23) - preferably before attachment to the shaft (3) - provided with a hard material layer (21), and at least one groove (N) is introduced at least into the hard material layer (21) in order to realize at least one geometrically defined cutting edge.

22. The method according to claim 21, characterized in that the hard material layer (21) only on the end face (23) of the head (5) is applied.

23. The method according to claim 21 or 22, characterized in that the thickness of the hard material layer is chosen so that it corresponds to the length of the at least one cutting edge.

24. The method according to any one of the preceding claims 21 to 23, characterized in that the hard material layer is annular is formed, wherein the width of the ring is preferably equal to or greater than the depth of the groove (N).

25. The method according to any one of the preceding claims 21 to

24, characterized in that the hard material layer (21) PKB and / or PCD has.

26. The method according to any one of the preceding claims 21 to

25, characterized in that the head (5) is cut from a larger base element.

27. The method according to claim 26, characterized in that the head (5) is cut out of the base body by means of a laser or by means of wire erosion.

28. The method according to any one of the preceding claims 21 to 27, characterized in that the first structure (15) and / or the second structure (19) are manufactured in a non-machining process.

29. Method according to claim 28, characterized in that the first and / or second structure (15, 17) is / are produced by means of a laser or by means of an erosion process.

30. The method according to any one of the preceding claims 21 to 29, characterized in that at least one groove (N) is introduced into the peripheral surface of the head (5).

31. The method according to claim 30, characterized in that a groove (N) in the peripheral surface of the shaft (3) is introduced.

32. The method according to any one of the preceding claims 21 to 31, characterized in that the groove (N) is realized as a chip groove.

33. The method according to claim 32, characterized in that the groove (N) runs parallel to the longitudinal axis (13) of the tool (1) or along an imaginary concentric with the longitudinal axis (13) lying helix.

34. The method according to any one of the preceding claims 21 to 33, characterized in that the head (5) is provided prior to attachment to the shaft (3) with a contour from which the at least one blade made, preferably ground, is.