METHOD AND MACHINE EQUIPMENT FOR MANUFACTURING OF A CUTTING TOOL

Abstract

A method for multistep machining a cutting tool includes defining a data set of the cutting tool, positioning the workpiece in a machining device, determining a data set of the workpiece to be machined, defining at least one machining program based on the defined data set in relation to the determined data set of the workpiece, subjecting the workpiece to the at least one machining program, to obtain intermediate geometries of the workpiece, determining a second data set by measuring means including the intermediate geometries of the workpiece and transferring the machined workpiece to a second machining device. Furthermore, the steps of positioning, determining data set of the workpiece, defining machining program, subjecting the workpiece to the machining program, determining a second data set and transferring to the second machining device are repeated until the workpiece takes on the shape of the target geometries.

Claims

1. Method for multistep machining a cutting tool, comprising the steps: a) Defining a data set of the cutting tool comprising target geometries of the cutting tool, parameters of materials of the cutting tool and/or parameters of process operations for machining a workpiece into the cutting tool; b) Positioning the workpiece in a machining device; c) Determining a data set of the positioned workpiece to be machined by a measuring method comprising actual geometries of shape, positional and orientation data of the positioned workpiece; d) Defining at least one machining program for the machining device based on the defined data set of the cutting tool in relation to the determined data set of the workpiece; e) Subjecting the workpiece to the at least one machining program, thereby obtaining intermediate geometries of the workpiece; f) Determining a second data set of the workpiece by measuring means comprising the intermediate geometries of the workpiece; g) Transferring the machined workpiece to a second machining device; h) Repeating steps b) to g) until the workpiece takes on the shape of the target geometries.

2. Method according to claim 1, wherein at least the second data set determined in step f) is processed to instantiate an actual model of the workpiece with intermediate geometries and is used to control the machining program applied in step e).

3. Method according claim 1, wherein the method comprises at least one rough machining step and at least one fine machining step.

4. Method according to claim 3, wherein the at least one rough machining step is selected from the group consisting of laser processing, grinding and electrical discharge machining.

5. Method according to claim 3, wherein the at least one fine machining step is selected from the group consisting of laser processing, grinding and electric discharge machining.

6. Method according to claim 1, wherein the measuring method to define the data set of the workpiece to be machined depends on the machining method to be performed.

7. Method according to claim 6, wherein the measuring method is a mechanical and/or optical method.

8. Method according to claim 1, wherein the data set of the workpiece defined in step c) comprises positional coordinates of machining fields related to a programming zero point determined within the workpiece.

9. Method according to claim 8, wherein positional coordinates of at least one reference point related to the workpiece and deviations of the programming zero point to the at least reference point of the workpiece are determined.

10. Method according to claim 9, wherein the at least one reference point is a center-of-gravity of the workpiece.

11. Method according to claim 9, wherein the machining program of step d) is adjusted according to the determined deviations of the programming zero point to the at least one reference point.

12. Method according to claim 1, wherein the target geometries of the cutting tool are generated from a set of parametrized templates.

13. Method according to claim 1, wherein before and/or after each machining step e) at least the shape of the workpiece is determined and is correlated to the target geometries of the cutting tool comprised in the data set to determine the following machining program.

14. A machining equipment for performing the method for machining a cutting tool according to claim 1, comprising: At least one first machining means for roughing a workpiece; At least one second machining means for finishing the workpiece; Measurement means for measuring a shape of the workpiece and determining positional and orientation data of the workpiece, and A control means for controlling the first machining means and/or the second machining means based on determined data sets of the workpiece to be machined and the defined data set of the cutting tool.

15. Machining equipment according to claim 14, wherein the measuring means comprises imaging means.

16. Machining equipment according to claim 14, wherein the measuring means comprises a probe.

17. Machining equipment according to claim 14, wherein the workpiece to be machined is positioned such to be machined by the first and/or second machining means in a loading prism.

18. Machining equipment according to claim 15, said imaging means comprising at least one of the following: CCD camera, infrared camera, near-infrared camera, laser scanner, laser triangulation, microscope, and/or interferometer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The invention will be explained more closely in the following by way of example, with reference to the attached drawing in which:

[0053] FIG. 1 shows a block scheme of the method according of the invention;

[0054] FIG. 2 is a schematic view of a workpiece showing a programming zero point and another reference point; and

[0055] FIG. 3 shows schematically a process for measuring a shape of a workpiece.

DETAILED DESCRIPTION OF THE DRAWING

[0056] The method for manufacturing of a cutting tool will be described with reference to FIG. 1. FIG. 1 is a block scheme showing main elements of the method according to a preferred embodiment of the invention. In FIG. 1, a control unit 10 is adapted to receive a data set 12 defining target geometries of a cutting tool to be manufactured, including design data indicating a final shape and dimensions of the cutting tool as well as data of finished surface qualities. Furthermore, information of material of the cutting tool and further information related to parameters of process operations to take a workpiece 14 into a shape of the finished cutting tool are stored. Said data set 12 can be stored in a data storage 16, wherein the geometry data, feature data, machining means data, material data and further relevant data can be stored as well in separate data storages comprised in the control unit 10. The control unit 10 is a functioning unit to store data in relation to the target cutting tool and in relation to the workpiece 14. The data set 12 is inputted through an on-line processing or in other appropriate way in the control unit 10. Furthermore, the control unit 10 can comprise individual control units such as decentral control units.

[0057] The workpiece 14 is positioned into a machining device in an appropriate way depending on the type of machining method performed by said machining device. The workpiece 14 to be machined can be referred as a blank which in step 18 is subjected to a measurement method to generate data necessary to generate a machining program to be performed in said machining device. The data set comprises at least geometry data of the workpiece 14 and is transmitted to the control unit 10, indicated by an arrow in FIG. 1. In a step 24, based on the geometry data, the control unit 10 generates a machining program to be performed in step 20. According to the invention, the measuring in step 18 is performed with the workpiece 14 positioned in said machining device, in particular in initally machining steps in a machining device for macroforming. The measuring of the workpiece 14 further gives information about the position of the workpiece 14 in the machining device and the orientation thereof.

[0058] After subjecting the workpiece 14 to a machining process in particular the macroforming step 20 the machined workpiece 14 is again subjected to measuring in step 22, for example by laser scanning to generate a data set of the intermediate geometry of the workpiece 14 which is transmitted to the control unit 10, indicated by an arrow in FIG. 1. The extracted geometry data can be computed such to instantiate an actual model of the workpiece 14 in that process stage. Said actual model can be set in relation to the data set 12 of the finished cutting tool to generate a machining program for the following process steps 26, etc.

[0059] As indicated by connection lines the determined data sets before and after machining of the workpiece 14 in step 20 each can be processed to control a machining program applied in step 20 wherein the machining program is further controlled by the defined data set 12 of the target cutting tool stored in the control storage 16 of the control unit 10.

[0060] Since the method according to the invention is a multistep process the workpiece 14 is subjected to further machining processes. Each successive machining process can be performed comparable to the previously described program, starting by a measuring step 18, subjecting the workpiece to machining 20 in a machining device and another measuring step 22. The process steps comprises at least one macroforming process, indicated by 24 and at least one microforming process, indicated by 26. Said program is controlled by the control unit 10 and provides a closed-loop control for the performed machining process. The process chain is indicated in FIG. 1 by blocks 24, 26. The successive machining steps can be performed in another machining device wherein transferring and positioning of the workpiece is included. At the end a cutting tool with desired geometries and qualities is manufactured.

[0061] FIG. 2 shows a schematic workpiece 14 which can be in the form of a rhombus with sides 14.1, 14.2, 14.3 and 14.4. FIG. 2 shows the workpiece 14 in plan view. According to the method of the invention, the shape and dimensions of the workpiece 14 is determined in step 18 previous each machining step 20 wherein appropriate measuring method is provided. Initially, a programming zero point 28 is defined in particular by an operator, wherein taking into account target geometries of the cutting tool. The programming zero point 28 is set in the volume of the workpiece 14 or on a surface of the workpiece 14. According to the invention, the programming zero point 28 can be seen as an origin of a coordinate system, crosspoint of coordinate axis, in particular the three coordinate axis x, y and z representing the three space directions. As can be seen in FIG. 2, the programming zero point 28 can differ from a reference point 30. In the embodiment shown in FIG. 2, the reference point 30 represents a center-of-gravity of the workpiece 14 but can be also every other suitable reference point 30. The reference point 30 is generated on the base of the measured geometry coordinates of the workpiece 14. This can be done based on measurements via optical means of an imaging proceeding technique wherein positions of the four sides 14.1, 14.2, 14.3, 14.4 of the workpiece 14 are determined.

[0062] Referring to FIG. 3, the workpiece 14 has in the shown embodiment a triangular form and is positioned in a loading prism 32 in relation to a machining device. As can be seen, the programming zero point 28 differs from the reference point 30.

[0063] According to one embodiment of the invention, one measurement method is based on a probe 34 to measure shape, dimensions and/or other parameters such as straight lines of the workpiece 14 relevant for the method of the invention and further to determine the reference point 30. The probe 34 can be displaced automatically towards the workpiece 14, in particular towards the surfaces 36, 38, 40 of the workpiece 14 wherein directions and displacements of the probe 34 can be processed to generate geometry coordinates of the surfaces 36, 38, 40 of the workpiece 14 related to the programming zero point 28. Based on the geometry, coordinates of the surfaces 36, 38, 40 of the workpiece 14 which are related to the programming zero point 28 coordinates of the reference point 30 can be extracted and deviations based on coordinates can be defined. Deviations of the programming zero point 28 to the reference point 30 are used for the machining program in particular to effect a machining path of a tool required to produce the desired path with high accuracy.