Device and method for producing a guide bevel on a workpiece, in particular on a cutting tool

Abstract

The invention relates to a method for producing a guide bevel on a workpiece, in particular a cutting tool. The workpiece to be machined is clamped in a clamping device which is rotationally driven about a rotational axis, and at least one laser unit is provided. The clamping device and the laser unit can be moved relative to each other by means of at least one CNC-controlled axis. The laser unit is of a type that is suitable for machining the workpiece by removing material. In order to produce the margin, the laser unit and the clamping device are controlled such that the workpiece in the clamping device is continuously rotated about the rotational axis of the clamping device at least by a specified angular amount while the laser unit and the clamping device are moved relative to each other at least by a specified distance in order to remove material from the workpiece so as to produce the guide bevel.

Claims

1. Method for producing a margin on a workpiece, wherein the workpiece is a cutting tool, wherein the workpiece to be machined is clamped in a clamping device which is rotationally driven about a rotational axis, and at least one laser unit is provided, wherein the clamping device and the laser unit are operable to be moved relative to each other by means of at least one CNC (computer numerical control)-controlled axis, and wherein the laser unit is of a type that is suitable for machining the workpiece by removing material, and wherein in order to produce the margin, the laser unit and the clamping device are controlled such that the workpiece in the clamping device is rotated about the rotational axis of the clamping device at least by a specified angular amount while simultaneously the laser unit and the clamping device are moved relative to each other at least by a specified distance in order to remove material from the workpiece so as to produce the margin, wherein the margin extends over a specified portion of the radial outer surface of the workpiece to be machined or a region of the margin extends over a specified portion of the radial outer surface of a cutting element of the workpiece, wherein in the specified portion of the radial outer surface of the workpiece or the specified portion of the radial outer surface of the cutting element of the workpiece, material is removed by means of a laser beam of the laser unit so as to produce the margin, wherein at least one of the at least one laser unit and the clamping device is movable relative to the other in the direction of one or more of an X-, Y-, Z-axis and simultaneously pivotable about one or more of the X-, Y-, Z-axis.

2. The method according to claim 1, wherein the clamping device is controlled and driven during production of the margin such that the workpiece in the clamping device continuously rotates about the rotational axis.

3. The method according to claim 1, wherein a measuring device is provided, with which measurements are carried out on the workpiece in the clamping device.

4. The method according to claim 3, wherein, following the machining and the measurement of the workpiece, the change to a new, unmachined workpiece is performed in an automated manner.

5. The method according to claim 1, wherein the clamping device and the laser unit are controlled such that the laser unit removes material successively from individual cutting edges of the cutting tool.

6. The method according to claim 1, wherein the workpiece is clamped, unsupported, in the clamping device.

7. The method according to claim 1, wherein the workpiece is clamped by one axial end in the clamping device, and is engaged by its other axial end with a tail centre.

8. The method according to claim 7, wherein the tail centre is controlled such that the workpiece is released from the tail centre after completion of the machining of the workpiece.

9. The method according to claim 7, wherein the tail centre is controlled such that a maximum-permissible axial holding force which is exerted on the workpiece by the tail centre is not exceeded, the maximum-permissible axial holding force being calculated in accordance with one or more dimensions of the workpiece.

10. The method according to claim 1, wherein the workpiece is clamped, suspended or upright, in the clamping device.

11. The method according to claim 1, wherein the laser beam produced by the laser unit is embedded, for its guidance, in a water jet.

12. The method according to claim 1, wherein the specified distance by which the laser unit and the clamping device can move relative to each other is subdivided into a plurality of partial distances.

13. The method according to claim 1, wherein at least one of the at least one laser unit and the clamping device is moved by means of at least four CNC-controlled axes.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) An embodiment of the present invention is described below with reference to the appended figures, in which:

(2) FIG. 1 shows a perspective view of a cutting tool to be machined;

(3) FIG. 2 shows a front view of this cutting tool to be machined;

(4) FIG. 3 shows an enlarged detail from FIG. 2;

(5) FIG. 4 shows a perspective view of a cutting element of the cutting tool according to FIGS. 1 and 2;

(6) FIGS. 5 to 8 show schematic, perspective views of machining situations of the tool using a laser according to the method according to the invention; and

(7) FIG. 9 shows a figure for the general understanding of the invention.

DETAILED DESCRIPTION

(8) FIG. 1 shows a perspective view of an embodiment of a tool which is machined as a workpiece with the method for producing a margin according to the invention. With the aid of FIG. 1 and also FIGS. 2 to 4, it will be clarified what is meant by a margin or circular land which is to be produced on a cutting tool with the method according to the invention. Furthermore, in this regard, reference is made to the explanations relating to FIG. 9 given in the introduction.

(9) The cutting tool 10 has cutting elements 12 and 14 which are received and fixed in corresponding recesses 16 and 18 in the tool 10, for example by soldering in. The cutting elements 12 and 14 each comprise a cutting edge 20 and 22. The cutting edges 20, 22 lie in a region of the cutting elements 12 and 14 which projects radially outwards beyond the outer circumference of the tool 10.

(10) FIG. 2 shows a front view of the tool 10. In FIG. 2, the cutting elements 12 and 14 with their respective cutting edges 20 and 22 can be seen again. The cutting edges 20 and 22 of the cutting elements 12 and 14 lie on the radius of an imaginary circle 24.

(11) FIG. 3 shows an enlarged view of the detail A from FIG. 2. In FIG. 3, there can be seen a portion of the tool 10 and a portion of the cutting element 12 with its cutting edge 20. Also shown is a portion of the imaginary circle 24 with specified radius. In the region of the cutting element 12 following the cutting edge 20, the region 26 extends on the radial outer surface of the cutting element 12. In the region 26, a margin is to be formed with the method according to the invention. The region 26 of the margin lies on the same radius of the imaginary circle 24 as the cutting edge 20. Below the margin, a clearance angle is provided by means of the chamfered portion.

(12) FIG. 4 shows a perspective view of the cutting element 12. In FIG. 4, the region 26 which corresponds to the margin is shaded in grey to show it clearly. The region 26 of the margin extends, starting from the cutting edge 20, over a specified portion of the radial outer surface of the cutting element 12. With the margin or circular land 26, the surface quality, i.e. inter alia the surface roughness of a bore wall for example, is influenced.

(13) FIG. 5 shows a schematic, perspective view of a machining situation of a workpiece, shown in FIGS. 1 to 4, using the method according to the invention.

(14) The tool 10 is in this case clamped as a workpiece in a clamping device (not shown) and can be continuously rotated in the direction of the arrow 28 about a rotational axis A of the clamping device. Moreover, the tool 10 can be moved relative to the laser beam 36 at least in the directions of the arrows 30, 32, 34 (X-, Y-, Z-direction) via the drivable clamping unit. Furthermore, a laser unit (not shown), which produces the schematically indicated laser beam 36, can also be moved relative to the tool 10 in the directions of the arrows 30, 32, 34. In other words, a relative movement between the tool 10 in the clamping device (not shown) and the laser beam 36 produced by a laser unit (not shown) can be executed while the tool 10 continuously rotates.

(15) To produce the margin or circular land on one of the cutting elements 12 and 14 in a region 26 (FIGS. 3 and 4) following the cutting edge 20, the tool 10 is continuously rotated about the rotational axis of the clamping device and rotates, for example, at a rotational speed of greater than 20 rpm, or is pivoted. Through the continuous rotation of the tool 10, the cutting elements 12 and 14 are successively guided through the laser beam 36, during which the laser beam 36 removes material from the region 26 in order to be able to form the margins. The cutting elements 12 and 14, which lie on the same radius (FIG. 2), thus pass through the laser beam 36 owing to the rotation, and the laser beam 36 acts successively on the cutting elements 12 and 14 so as to produce the margins.

(16) In addition to the continuous rotation of the tool 10, either the tool 10 (via the clamping device not shown) and also the laser unit (not shown) producing the laser beam 36 can be moved relative to each other at least in the directions of the arrows 30, 32, 34. The relative movement of the laser unit and the clamping device achieves the effect that the laser beam 36 can act, from different angles and positions, on the cutting element 12 and 14 to be machined. In other words, the tool 10 is continuously rotated about the rotational axis while, through a relative movement between the laser 36 and the tool 10, the laser 36 is guided along the region 26 (FIGS. 3 and 4) of the cutting elements 12 and 14 so as to produce the margins. The drive of the clamping device and of the laser unit is preferably effected via one or more CNC-controlled axes.

(17) By virtue of the continuous rotation of the tool about its rotational axis, the laser beam acts substantially tangentially on the region 26 (FIGS. 3 and 4) of the cutting elements 12 and 14 to be machined, which contributes, particularly in the case of tools with a plurality of cutting elements 12 and 14 or cutting edges, towards a quick and successive production of the geometries on the individual cutting elements 12 and 14 required for a margin.

(18) Naturally, with the method according to the invention, it is also possible to machine tools with a cutting edge or a cutting element and tools with more than two cutting edges or cutting elements.

(19) FIGS. 6 to 8 correspond largely to FIG. 4, but show that a relative movement between the clamping device and the laser unit is possible and the laser beam can also strike the workpiece to be machined, at different angles.

(20) FIGS. 5 to 8 show, besides the different possibilities for bringing the laser beam 36 onto the workpiece (tool) 10, additionally that the laser beam 36 is always represented by a cone. As a result, on the one hand the focusing of the laser beam onto the machining location is indicated, but on the other hand also the possibility that the laser beam can execute a rotating movement.

(21) In summary, it can be concluded that a markedly improved possibility for overcoming the relatively difficult problem of creating a circular land on a tool is obtained with the invention. In particular given the increasingly complicated workpiece geometries which are required for the time-saving machining of complex workpiece geometries, the present invention offers considerable advantages.