System and method for machining a workpiece

Abstract

A workpiece accommodation device for purposes of accommodating a workpiece and for use in a device for the machining of a workpiece with: a tool mounting for purposes of accommodating the tool, a workpiece accommodation device for purposes of accommodating the workpiece, characterized in that during the machining process at least one first oscillation component can be introduced in a Z-direction, and an, in particular simultaneous, second oscillation component can be introduced in an X- and/or Y-direction by means of oscillation components.

Claims

1. A system for machining a workpiece surface of a workpiece, the system comprising: a tool having a tool surface for the machining of the workpiece surface in a feed direction v, a workpiece holder for accommodating the workpiece, wherein the workpiece is configured such that it can be set into oscillation by means of oscillation agents along a plane of oscillation E inclined to the feed direction v, wherein at least the tool surface is formed from at least two different materials, the tool surface including a first material and a second material that projects out of the first material with an average utilisation length, and wherein an oscillation amplitude of the oscillation agents is less than the average utilisation length.

2. The system in accordance with claim 1, wherein the first material of the tool surface is a matrix material and the second material of the tool surface is at least one chisel embedded in the matrix material.

3. The system in accordance with claim 2, wherein the matrix material is formed from one or more of the following materials: an alloy, a metal, a ceramic, and a carbon fibre composite material.

4. The system in accordance with claim 2, wherein the at least one chisel is formed from one or more of the following materials: a mineral, an alloy, and a metal.

5. The system in accordance with claim 2, wherein the average size of the at least one chisel is less than 1000 m.

6. The system in accordance with claim 2, wherein more than 20% of the volume of the at least one chisel is embedded in the matrix material.

7. A method for the achining of a workpiece surface of a workpiece, the method comprising: machining the workpiece surface with a tool having a tool surface, formed from at least two different materials, the workpiece surface being machined in a feed direction v, oscillating a workpiece holder for accommodating the workpiece along a plane of oscillation E inclined to the feed direction v, wherein the tool surface comprises a first material and a second material that projects out of the first material with an average utilisation length, and wherein the workpiece holder is oscillated at an oscillation amplitude that is less than the average utilisation length.

8. The system in accordance with claim 3, wherein the alloy is selected from one or more of the following: a steel, a carbide, a refractory metal and/or a metal matrix composite materials (MMC).

9. The system in accordance with claim 8, wherein the steel s a tool steel.

10. The system in accordance with claim 9, wherein the tool steel is selected from one or more of the following: a high-speed steel (HSS), a hot-working steel, and/or a cold-working steel.

11. The system in accordance with claim 3, wherein the metal is selected from one or more of the following: a crystalline metal, a quasi-crystalline metal and/or an amorphous metal.

12. The system in accordance with claim 4, wherein the mineral is in elemental form.

13. The system in accordance with claim 12, wherein the elemental form is a diamond.

14. The system in accordance with claim 4, wherein the alloys are selected from one or more of the following: a steel, a carbide, a refractory metal, and/or a metal matrix composite material (MMC).

15. The system in accordance with claim 14, wherein the steel is a tool steel.

16. The system in accordance with claim 15, wherein the tool steel is selected from one or more of the following: a high-speed steel (HSS), a hot-working steel, and/or a cold-working steel.

17. The system in accordance with claim 4, wherein the metal is selected from one or more of the following: a crystalline metal, a quasi-crystalline metal and/or an amorphous metal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a schematic representation of a form of embodiment of the inventive system,

(2) FIG. 2a shows a schematic plan view of a first inventive surface of a tool with a high density of microchisels,

(3) FIG. 2b shows a schematic side view of the surface along the line of cut A-A in FIG. 2a,

(4) FIG. 3a shows a schematic plan view of a second inventive surface of a tool with a low density of microchisels,

(5) FIG. 3b shows a schematic side view of the surface along the line of cut B-B in FIG. 3a,

(6) FIG. 4 shows a schematic representation of an Si.sub.3N.sub.4-structure, and

(7) FIG. 5 shows a schematic, enlarged representation of the movement of an inventive chisel relative to the workplace.

DETAILED DESCRIPTION OF THE INVENTION

(8) FIG. 1 shows a schematically represented tool 1, not to scale, (here a roughing milling cutter) with a tool surface 1o. The tool experiences a feed in a feed direction v, and in the particular form of embodiment rotates about an axis of rotation R/tool longitudinal axis W. From the direction of rotation a cutting direction s ensues along a workpiece surface 4o of a workpiece 4 that is being machined.

(9) The tool surface 1o of the tool 1 contacts the workpiece 4 on the workpiece surface 4o. The workpiece 4 is mounted/fixed on a workpiece holder 5. With regard to the workpiece holder 5 reference is made to W02012/084779A1. The workpiece holder 5 is constructed such that it can allow the workpiece 4 to oscillate along a plane E; the vector En normal to the plane possesses an angle of inclination to the tool longitudinal axis W, and/or is inclined relative to the feed direction v and/or the cutting direction s.

(10) To this end the workpiece holder 5 is comprised of a first oscillation element 8 and a second oscillation element 9 guided relative to the first oscillation element 8 along the inclined plane E.

(11) Oscillation agents, preferably in the form of piezoelements 10, are provided in order to execute a movement of the oscillation elements 8, 9 relative to one another.

(12) The piezoelements 10 connect the two oscillation elements 8 and 9 with one another such that by means of a reciprocal electrical loading of a piezoelement 10, a relative movement takes place between the oscillation elements 8 and 9. By the electrical loading of the piezoelements 10 a high-frequency oscillating movement between the two oscillation elements 8 and 9 is possible. Needless to say, use of mechanical, pneumatic or hydraulic elements would also be conceivable; these would replace the piezoelements 10.

(13) FIG. 2a shows an enlarged detail of the tool surface 1o of the tool 1, comprised of a plurality of microchisels 3, here diamonds. The distance L.sub.D characterises the distance between two microchisels. Since the microchisels 3 in general are not homogeneously distributed in the matrix material 2, an average distance Lm is specified, which represents the (arithmetically) averaged distance between the microchisels 3.

(14) FIG. 2b shows a cross-section through the tool surface 1o along the line of cut A-A.

(15) The tool surface 1o is comprised of a matrix material 2 and a multiplicity of chisels 3 embedded in the matrix material 2,

(16) The chisels 3 possess a utilisation part 3n projecting out of the tool surface 1o, and an anchor part 3a embedded in the matrix material 2. The average length of the utilisation part 3n is the utilisation length L.sub.N, the average length of the anchored part is L.sub.A.

(17) FIGS. 3a and 3b show analogous schematic representations of a corresponding tool surface 1o, but with a lower density/number of microchisels 3. The number of microchisels 3 per square millimeter is greater than 1, preferably greater than 10.sup.1, more preferably greater than 10.sup.2, even more preferably greater than 10.sup.3, most preferably greater than 10.sup.4, ideally greater than 10.sup.6.

(18) FIG. 4 shows a schematic structure 6 of a high strength material, here a ceramic. The schematic structure 6 preferably takes the form of a silicon nitride (Si.sub.3N.sub.4) structure. The structure 6 is in particular distinguished by grains 7 with an elongated, in particular a needle-shaped, constitution. The grains 7 perceived to be almost circular only appear to be globular. In actual fact these are the same elongated grains 7. In the view (ground section) the grains 7 are lying such that their longest axis is located approximately normal to the grinding plane.

(19) FIG. 5 shows the inventive efficient machining of high-strength, hard, and ultra-hard structures 6. The inventive combination of a tool surface 1o with microchisels 3 projecting out of the matrix material 2, and the imposition of an inclined oscillation, leads to the fact that the workpiece surface 4o moves at a constant, and in particular a reproducible, angle relative to the microchisels 3. Upon contact of the microchisel 3 with a grain 7 in the workpiece surface 4o, the grain 7 is subjected to a horizontal loading with a force component F.sub.H and a vertical loading with a force component F.sub.V. Here the following inventive aspects are of inventive and decisive significance:

(20) The movement of the workpiece holder 5, and with it the workpiece 4 along the plane E, is independent of, and/or transverse to the feed movement v and/or the cutting direction s, that is to say, the direction of rotation of the tool 1, and can be adjusted in any manner.

(21) The oscillation along the plane E, upon contact of the microchisel 3 with a grain 7 of the structure 6 on the workpiece surface 4o, always leads to the formation of a horizontal and a vertical force component, in particular as a result of a relative movement of two oscillation elements along an inclined plane E, and

(22) The forces that thereby result are added to the tool forces of the moving tool 1, in particular to the cutting forces and/or the feed forces,

(23) The three points cited mean that the structure 6 experiences a loading that releases the grains 7 out of the structure 6 with extremely high efficiency.

(24) While in the prior art the machining of a structure 6 as represented, in particular a ceramic structure, up to the present day has in general been possible, this has only been with very rapid wear of the tool, very long machining times and very low tolerances. As a result relatively high production costs occur. The inventive tool uses a surface with microchisels in order to bring about optimal chip formation. The inventive tool operates particularly efficiently in conjunction with the equipment from the document W02012/084779A1. The most favourable machining of a workpiece with the inventive tool takes place if the workpiece is moved in an oscillatory manner along an inclined plane with the aid of the equipment from the document W02012/084779A1.

(25) An inventively essential aspect includes primarily in using the tool surface 1o with microchisels 3 so as to machine efficiently a workpiece surface 4o of a workpiece 4, which has been fixed on a workpiece holder 5.

(26) Here, in particular, the oscillation of the workpiece 4 along the inclined plane E is utilised so as to subject the workpiece surface 4 to a horizontal and vertical force by means of the microchisels.

LIST OF REFERENCE SYMBOLS

(27) 1 Tool 1o Tool surface 2 Matrix material 3 Microchisels 3n Outer part of the embedded material 3a Inner part of the embedded material 4 Workpiece 4o Workpiece surface 5 Workpiece holder 6 Structure 7 Grain 8 First oscillation element 9 Second oscillation element 10 Piezoelement v Feed direction s Cutting direction R Axis of rotation W Tool longitudinal axis E Plane of oscillation En Normal to the plane of oscillation Angle of inclination L.sub.N Utilisation length L.sub.A Anchor length L.sub.D Distance Lm Average distance F.sub.H Horizontal force action F.sub.V Vertical force action