Method and Device for Machining a Workpiece

Abstract

In a method for machining a workpiece (1), the workpiece (1) is secured to a carrier element (2) by at least one connecting element (4) or is produced by a generative production method. In an embedding step, the workpiece (1) is introduced into a casting mould surrounding the workpiece (1) and a curing carrier material (16) surrounding the workpiece (1) is introduced into the casting mould, such that the workpiece (1) is embedded and fixed in the carrier material (16). In an exposure step, the carrier material (2) is separated from the workpiece (1) and the workpiece (1) is exposed from a side facing the carrier element (2), in order, in a subsequent second machining step, for it to be possible to machine the workpiece (1) partially embedded in the carrier material (16). The workpiece (1) can be produced by a generative production method on the carrier element (2), wherein at least one connecting element (4) that joins the workpiece (1) to the carrier element (2) is produced at the same time. Arranged on the carrier element (2) are protruding positioning elements (6), which, when the workpiece (1) is introduced into the casting mould (10), come into engagement with matching recesses in the casting mould, in order to define a position of the carrier element (2) with the workpiece (1) secured thereto relative to the casting mould and to allow subsequent referencing of the workpiece (1).

Claims

1.-21. (canceled)

22. A method for machining a workpiece which is fixed on a carrier element by at least one connecting element, comprising: an embedding step, in which the workpiece is inserted into a casting mold enclosing the workpiece and a curing carrier material enclosing the workpiece is introduced into the casting mold, so that the workpiece is embedded and fixed in the carrier material; an exposure step, in which the carrier element is separated from the workpiece and the workpiece is exposed from a side facing the carrier element; and a subsequent machining step, in which the workpiece partially embedded in the carrier material is machined.

23. The method according to claim 22, wherein the workpiece is manufactured on the carrier element by a generative manufacturing process and at least one connecting element connecting the workpiece to the carrier element is also manufactured.

24. The method according to claim 22, wherein positioning elements are arranged on the carrier element or on the workpiece.

25. The method according to claim 24, wherein, on introduction of the workpiece into the casting mold, the projecting positioning elements engage in recesses adapted thereto in the casting mold in order to specify a positioning of the carrier element with the workpiece fixed thereon relative to the casting mold.

26. The method according to claim 24, wherein at least three positioning elements are arranged spaced at an interval from one another.

27. The method according to claim 24, wherein the positioning elements are positioning pins projecting from the carrier element.

28. The method according to claim 24, wherein the positioning elements are each connected by way of at least one connecting element to the carrier element.

29. The method according to claim 24, wherein the positioning elements are connected to the workpiece via stabilizing elements.

30. The method according to claim 24, wherein the positioning elements are manufactured together with the workpiece by a generative manufacturing method.

31. The method according to claim 22, wherein the casting mold is configured in multiple parts and following the curing of the carrier material is taken apart and demolded from the cured carrier material.

32. The method according to claim 31, wherein the casting mold has a casting mold base element and a side wall ring element connectable detachably to the casting mold base element, and wherein the side wall ring element is detached and removed from the casting mold base element before or after the exposure step.

33. The method according to claim 24, wherein the carrier material is removed from the casting mold with the workpiece and with the positioning elements and is fixed in a positioning device before subsequent machining of the workpiece takes place.

34. The method according to claim 33, wherein following the fixing of the carrier material in the positioning device, the positioning elements projecting from the carrier material are scanned and used for referencing of the workpiece.

35. The method according to claim 33, wherein during the embedding step, at least one fixing element is embedded into the carrier material in an edge area facing the casting mold, which element is partly exposed following curing of the carrier material and is used for locating in a positioning device.

36. The method according to claim 22, wherein the carrier material is a curing molding compound, an embedding compound, a wax or a thermoplastic plastic material.

37. The method according to claim 22, wherein the carrier material is a eutectic alloy.

38. A device for locating and machining a workpiece, comprising: a carrier element, on which the workpiece can be arranged and fixed; and a casting mold, which can be connected detachably to the carrier element, and which encloses the workpiece and can be filled with a carrier material enclosing the workpiece.

39. The device according to claim 38, wherein the device has positioning elements connectable to the carrier element, which positioning elements can each be brought into engagement with a recess adapted thereto in the casting mold, in order to specify a positioning of the carrier element relative to the casting mold.

40. The device according to claim 39, wherein the recesses in the casting mold provided for engagement with a positioning element each have a seal, with which a gap between the positioning element and an adjoining area of the casting mold is sealed, so that no carrier material can penetrate into the recesses.

41. The device according to claim 38, wherein the casting mold is configured in two parts or multiple parts and the multiple parts of the casting mold are connectable detachably to one another.

42. The device according to claim 41, wherein the casting mold has a casting mold base element and a multipart side wall ring element detachably connectable thereto.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 to FIG. 5 show schematic snapshots during the manufacture and machining of two workpieces by the disclosed method and using the disclosed device.

[0042] FIG. 6 shows a schematic snapshot before an embedding step, wherein several workpieces are additionally connected to one another by stabilizing elements.

[0043] FIG. 7 is a schematic depiction of a molding formed of a cured carrier material, in which two workpieces and three positioning elements are embedded.

[0044] FIG. 8 is a schematic depiction of the molding depicted in FIG. 7, which is taken up in a locating device of a machining machine and permits simultaneous machining of the two workpieces from opposing outer surfaces,

[0045] FIG. 9 is an enlarged partial view of a sealed recess in a casting mold in which a positioning element engages.

[0046] FIG. 10 is an enlarged partial view of an edge area of the molding formed from the cured carrier material in the casting mold, wherein a fixing element was inserted into the edge area as an insert component during the embedding step.

[0047] FIG. 11 is an enlarged partial view of the molding from the carrier material depicted in FIG. 10, wherein the casting mold was removed and a portion of the fixing element exposed, in order to make a gripping section of the fixing element accessible.

DETAILED DESCRIPTION

[0048] FIGS. 1 to 5 show several snapshots of a manufacturing and machining method. FIG. 1 schematically depicts a manufacturing step, wherein using a generative manufacturing process such as 3D printing or selective laser melting, for example, two workpieces 1 are generated and solidified in layers on a carrier element 2 configured in the shape of a disc. The carrier element 2 here is taken up in a locating device, which is not shown in greater detail, and is fixed in its position and situation. The two workpieces 1 are arranged on a level surface 3 of the carrier element 2 and each connected to the carrier element 2 and fixed thereto via several connecting elements 4. An underside 5 of the workpieces 1 has a spacing of, for example, one or more millimeters from the surface 3 of the carrier element 2.

[0049] At the same time as the generative manufacture of the two workpieces 1, several positioning elements 6 are produced generatively. The positioning elements 6 are formed pin-shaped, project perpendicularly from the level surface 3 of the carrier element 2 and have a rounded end area 7. In contrast to the two workpieces 1, the positioning elements 6 are connected not via connecting elements 4 but directly on and to the carrier element 2 and fixed thereon.

[0050] In a following first machining step (FIG. 2), the finished workpieces 1 could be machined with a suitable machining tool 8. Surface post-machining of the workpieces 1 can be undertaken with the machining tool 8, for example. However, on account of the fixing of the workpieces 1 on the carrier element 2, only one side 9 of the workpieces 1 facing away from the carrier element 2 is accessible to the machining tool 8 in each case, so that only the side 9 facing away from the carrier element 2 can be machined using the machining tool 8. Such a first machining step is not absolutely necessary in many cases.

[0051] In a subsequent embedding step shown schematically in FIG. 3, a casting mold 10 is connected after the first machining step to the carrier element 2, wherein the casting mold 10 encloses the two workpieces 1 as well as the positioning elements 6. The positioning elements 6 engage with the end areas 7 in recesses 11 adapted thereto in the casting mold 10 and form a positive-locking positioning and positional fixing of the casting mold 10 relative to the carrier element 2. The positioning elements 6 embedded together with the workpieces 1 also form measuring points, the position of which is exactly specified. The positioning elements 6 can also be scanned prior to a subsequent machining step and used for referencing of the workpieces 1.

[0052] The casting mold 10 consists of a casting mold base element 12 formed in a pot-like manner and of a side wall ring element 13, which is formed in turn from two half-rings 14 formed in a half-ring shape. The half-rings 14 can be assembled detachably with one another to form the annular side wall ring element 13 and be connected likewise detachably to the casting mold base element 12 and removed from the casting mold base element 12 at a later time.

[0053] The casting mold 10 connected to the carrier element 2 forms a hollow cavity 15, in which the two workpieces 1 are arranged. Introduced into the hollow cavity 15 is an initially liquid carrier material 16, with which the hollow cavity 15 is filled and the two workpieces 1 completely enclosed. The initially liquid carrier material 16 then cures. The two workpieces 1 are then completely enclosed by the carrier material 16 and embedded therein, so that the workpiece 1 and the positioning elements 6 are fixed by the surrounding cured carrier material 16 in their position inside the casting mold 10.

[0054] The casting mold 10 can be taken up in a locating device, which is not depicted in greater detail, and fixed in its position.

[0055] In a subsequent exposure step depicted schematically in FIG. 4, the two half-rings 14 are detached from one another and from the casting mold base element 12 as well as from the carrier element 2 and are removed. The carrier element 2 is then separated from the casting mold 10 and the carrier material 16 cured therein along the level surface 3 using a band saw 17. To separate the carrier element 2 any suitable mechanical separating apparatus, for example a blade or saw, can be used. The carrier element 2 can also be eroded. In this case a thin slice of the carrier material 16 in an area close to the surface 3 of the carrier element 2 can be destroyed. During the separation of the carrier element 2 the positioning elements 6 and the connecting elements 4 that have connected the workpieces 1 to the carrier element 2 are also severed.

[0056] The two workpieces 1 can then be exposed as required from a side 19 originally facing the carrier element 2 using a suitable machining tool 18, in order to facilitate machining of the two workpieces 1 from the side 19 originally facing the carrier element 2 in a following second machining step, as is shown schematically in FIG. 5. After machining of the two workpieces 1 now from all sides 9, 19, the workpieces 1 can be completely removed from the carrier material 16. The carrier material 16 can be first taken out of the casting mold base element 12 or demolded for this purpose. The carrier material 16 can then be removed completely and without residues from the workpieces 1 using suitable methods.

[0057] In the exemplary embodiment shown by way of example in FIG. 6, several small workpieces 1 are connected to one another by stabilizing elements 20 for the purpose of additional stabilization. The stabilizing elements 20 can be produced using the normal generative manufacturing processes together with the workpieces 1 and the positioning elements 6. A number of small workpieces 1 can be reliably fixed on a carrier element 2 in this way and machined from all sides using the disclosed method. The positioning elements 6 can also be connected to the workpieces 1 by stabilizing elements 20 to achieve additional stability and more accurate referencing.

[0058] An advantageous configuration of the method is depicted by way of example in FIGS. 7 and 8. Following the manufacture of the workpieces 1 and the positioning elements 6 on the carrier element 2, a casting mold 10 formed of two half-ring-shaped wall shells 21 is placed onto the carrier element 2 so that the workpieces 1 and the positioning elements 6 are enclosed by the two half-ring-shaped wall shells 21. In the embedding step the curing carrier material 16 is then poured into the casting mold 10, wherein the filling level for the carrier material 16 is measured so that upper end areas 22 of the positioning elements 6 are not covered by the carrier material 16 and they project. Following the curing of the carrier material 16, the two half-ring-shaped wall shells 21 are demolded and the carrier element 2 separated from the remaining molding 23. The two workpieces 1 and the positioning elements 6 are embedded in the molding 23, the outer shape of which was determined by the casting mold 10 in the area of a circumferential sheath.

[0059] Following take-up of the molding 23 in a locating device 24 indicated in FIG. 8, the end areas 22 of the positioning elements projecting from the molding 23 can be scanned and used for referencing of the workpieces 1 in the molding 23. Very accurate positional recording of the workpieces 1 in the molding 23, which is taken up in the locating device 24 and fixed in position, is possible by this.

[0060] In a subsequent machining step, surfaces 25 and 26 lying opposite one another can then be machined simultaneously or consecutively using suitable machining tools 8, 18, without the molding 23 having to be removed from the locating device 24 and located afresh, and without gripping adversely affecting the preceding referencing and thus the precision achievable in machining of the workpieces 1.

[0061] FIG. 9 depicts a recess 11 in the casting mold 10 in an enlarged view by way of example. An end area 22 of a positioning element 6 protrudes during the embedding step into the recess 11. To prevent the still liquid carrier material 16 from penetrating into the recess 11 through a gap between the positioning element 6 and the area of the casting mold 10 bordering the recess prior to curing, a sealing ring 27 is inserted into a groove 28 running along the circumference of the recess 11. The sealing ring 27 seals the annular gap between the positioning element 6 and the casting mold 10 and prevents the end area 22 of the positioning element 6 from being moistened and coated by the carrier material 16.

[0062] FIGS. 10 and 11 show purely schematically that during the embedding step, additional fixing elements 29 can also be embedded as an insert part in an edge area 30 on the casting mold 10 in a connecting area of the two half-rings 14 of the side wall ring element 13 in such a way in the molding 23 formed by the carrier material 16 that a gripping section 31 of the fixing element 29 is surrounded by the two half-rings 14 and an anchoring area of the fixing element 29 is embedded into the carrier material 16. Following the curing of the carrier material 16, the casting mold 10 can be demolded in order to expose the gripping section 31 of the fixing element 31, which continues to be anchored in the remaining molding 23. The exposed gripping section 31 can be used to grip the molding 23 before a subsequent machining step and to take it up and fix it in a suitable locating device of a machining machine.

[0063] In an advantageous configuration of the method, first the workpieces 1 and the positioning elements 6 are produced with the aid of a generative manufacturing method on the carrier element 2. Then the workpieces 1 and the positioning elements 6 are enclosed in an embedding step by a casting mold 10 and embedded in a curing carrier material 16. The casting mold 10 and the carrier element 2 are demolded and separated from the molding 23 formed from the cured carrier material 16. The molding 23 is taken up in a locating device 24 and fixed in position. The end areas 22 of the positioning elements 6 protruding from the molding 23 are scanned and the workpieces 1 embedded in the molding 23 are referenced, so that their position relative to the locating device 24 is exactly known. Then the surfaces 25, 26 of the workpieces 1 can be post-machined in a subsequent machining step with suitable machining tools 8, 18.