METHOD FOR SETTING UP A WORKPIECE RECEIPT

Description

[0001] The invention relates to a method for setting up a dental milling machine.

[0002] In this context, DE 20 2013 103515 U1 and US 2014 / 147225 A1 are cited as state of the art.

[0003] For the production of dental prostheses, such as crowns, bridges, or similar items, blanks made of various materials are machined in dental milling machines. These blanks are generally standardized in terms of their dimensions, allowing them to be used across different dental milling machines. However, manufacturers are now selling dental milling machines that can only accommodate blanks with non-standard dimensions. This means users are limited to using the blanks specifically designed for their milling machine, making flexible use of the machine impossible.

[0004] If a blank is clamped in the workpiece holder for machining during normal operation of the dental milling machine, it must be ensured before machining begins that the coordinate system of the actual workpiece, in this case the blank, matches the coordinate system of the programmed, virtual workpiece. This requires calibration of the workpiece holder before commissioning the dental milling machine.

[0005] Dental milling machines are known to use a calibration method where a test workpiece with several reference points is clamped into the workpiece holder. A probe clamped in the tool holder approaches these reference points. The coordinates recorded at the reference points are stored in the dental milling machine's control system. Based on these reference points, the virtual coordinate system of the workpiece holder, and thus also of the workpiece, is adjusted. In a further calibration step, a reference workpiece is milled, the target geometry of which is stored in the dental milling machine's control system. The geometry of the reference workpiece is measured and compared with the target geometry. Based on the deviation between the actual and target geometry of the reference workpiece, the virtual coordinate system can be corrected.This step can be repeated until the reference workpiece is manufactured with sufficient accuracy. Such calibration of the dental milling machine is extremely time-consuming and expensive. Due to the complexity of the calibration, it usually has to be performed by service technicians.

[0006] The objective of an unclaimed measure is to further develop a dental milling machine in such a way that the dental milling machine can be set up in a simple manner and is also flexible in its use.

[0007] An unclaimed measure is based on the further task of specifying a means that enables simple setup and at the same time flexible use of a dental milling machine.

[0008] The invention is based on the objective of providing a method that enables simple setup and flexible use of a dental milling machine.

[0009] The problem relating to the method is solved by a method according to the features of claim 1.

[0010] The dental milling machine includes a workpiece holder. The workpiece holder comprises a bracket and an adapter. The adapter is attached to the bracket. The adapter has at least one receptacle for attachment to the bracket of the dental milling machine. In its initial state, the adapter is a blank and designed to be milled by the dental milling machine.

[0011] Before the workpiece holder is activated, the adapter is milled to achieve the contour required to hold a blank. The operator can, for example, specify the appropriate milling operation depending on the blanks to be processed, thus achieving the desired contour on the adapter. Therefore, any contour tailored to the operator's requirements can be incorporated into the adapter, adapted to the blanks used by the operator. Consequently, the dental milling machine is not limited to processing specific blanks but can be used for a wide range of blanks.

[0012] Another advantage of the dental milling machine is that milling over the adapter eliminates the need for additional calibration. The contour for holding the workpiece is milled into the adapter, thus defining the position of the workpiece holder in the dental milling machine. The control system of the dental milling machine knows the exact position of the workpiece holder because it corresponds to the position of the contour programmed for milling. When milling over the adapter, any inaccuracies of the dental milling machine are transferred to the adapter, thereby aligning the zero points of the workpiece holder and the dental milling machine relative to each other.

[0013] Preferably, the adapter is milled in a second state by the dental milling machine and includes a contour for receiving a blank. Therefore, in this second state of the adapter, a workpiece can be held in the workpiece holder.

[0014] Preferably, the adapter is made of plastic, particularly injection-molded plastic. Plastic provides sufficient strength to hold workpieces during milling. At the same time, plastic is significantly easier to mill than alternative materials suitable for such an adapter, such as aluminum or other metallic materials. The holder is preferably made of aluminum.

[0015] The adapter is held securely and detachably on the holder. For each blank's mounting contour, an adapter with a custom contour can be provided. If multiple blanks with different mounting contours are to be processed in the dental milling machine, the adapter can be easily changed and the corresponding blank processed.

[0016] The workpiece holder includes at least one clamping device. The clamping device is preferably held on the adapter. When the blank is clamped in the workpiece holder, the blank rests on the adapter and is clamped against the adapter by the clamping device.

[0017] In its first state, the adapter is preferably arc-shaped. Commercially available blanks are circular and disc-shaped. In its second state, the adapter has a contour at least partially inverse to that of the blank, preferably also arc-shaped, and in particular semicircular. To enable fast milling, the contour of the adapter in its first state is similar to the contour in its second state. However, it may also be advantageous to provide a different contour for the adapter in its first state. This could be the case, for example, if differently shaped workpieces, such as polygonal workpieces or the like, are to be held on the adapter.

[0018] It is preferably provided that the bracket has at least one lateral stop for positioning the adapter. When changing an adapter, it is pushed against the stop and then screwed into place. This ensures sufficiently precise positioning of the adapter. Advantageously, the bracket and the adapter are aligned relative to each other via a dowel pin.

[0019] The inventive method for setting up a dental milling machine provides for a dental milling machine, wherein the dental milling machine has a workpiece holder, the workpiece holder comprising a bracket and an adapter, the adapter being attached to the bracket. The adapter is a blank and is milled by the dental milling machine in such a way that a receiving contour for receiving a blank is formed on the adapter.

[0020] Preferably, at least one clamping device is attached to the adapter. The clamping device is attached to the adapter, in particular, after the adapter has been milled. When machining a blank, the blank is held between the adapter and the at least one clamping device.

[0021] Further features of the invention will become apparent from the description and the drawing, in which a detailed embodiment of the invention is shown below. The drawing shows: Fig. 1 shows a perspective view of a dental milling machine, Fig. 2 shows a perspective view of the dental milling machine according to Fig. 1 with the loading flap open, Fig. 3 in perspective view an arrangement of a carrier and a workpiece holder with adapter, Fig. 4 in perspective view from above an adapter as a blank for the workpiece holder Fig. 5 in perspective view from below the adapter after Fig. 4Fig. 6 shows the adapter in a perspective view after milling, Fig. 7 shows the adapter in a perspective view after milling. Fig. 6 with clamping devices, Fig. 8 in perspective view the holder, Fig. 9 in a front view of the adapter after Fig. 6 with clamping devices, Fig. 10 in a perspective view an arrangement of the carrier and the workpiece holder with clamped blank, Fig. 11 in a perspective view an arrangement according to Fig. 10 with swiveled workpiece holder, Fig. 12 in a perspective view an alternative blank for a workpiece holder and Fig. 13 in a perspective view an adapter with an alternative holder geometry with clamping means.

[0022] In Fig. 1A dental milling machine 1 is shown. The dental milling machine 1 is designed for the production of dental prostheses, in particular for the manufacture of crowns and bridges. Such a prosthesis is manufactured from a blank – hereinafter referred to as blank 15. The dental milling machine 1 has a housing 2 with a loading flap 3. The housing 2 defines an interior space 9 of the dental milling machine 1. After opening the loading flap 3, access to the interior space 9 of the dental milling machine 1 is provided, allowing, for example, the insertion or removal of a blank 15. The housing 2 of the dental milling machine has a top surface 46 and a bottom surface 47. Several feet 45 are arranged on the bottom surface 47 of the dental milling machine 1, and the dental milling machine 1 rests on these feet 45. The term "top" indicates a direction extending from the bottom surface 47 to the top surface 46 of the dental milling machine 1.The term "bottom" refers to a direction running from the top 46 to the bottom 47 of the dental milling machine 1.

[0023] As in Fig. 1 In the schematic representation, a milling spindle 5 is arranged in the dental milling machine 1. The milling spindle 5 comprises an electric motor 49 and a spindle 48 driven by the electric motor 49. In the exemplary embodiment, the milling spindle 5 is adjustable translationally in space, i.e., in the direction of the x, y, and z axes of the dental milling machine 1, via a drive system not shown in detail. In the preferred embodiment, the milling spindle 5 is preferably adjustable rotationally and can be pivoted about the degrees of freedom A and B, i.e., about the x-axis and the y-axis, respectively. The degrees of freedom of the milling spindle are defined in Fig. 1 schematically indicated. Furthermore, the dental milling machine 1 includes a Fig. 1Control unit 4 is shown only schematically. The control unit 4 serves to supply and control the milling spindle 5 and the drive system. The milling spindle 5 and the drive system are connected to the control unit 4, in particular via an electrical connection.

[0024] In Figure 2 The dental milling machine 1 is shown with the loading flap 3 open. The open loading flap 3 exposes a loading opening 8. Through the loading opening 8, blanks 15 can be guided into the interior 9 of the dental milling machine 1 and inserted into a workpiece holder 10 of the dental milling machine 1. As shown in Figure 1As shown, the workpiece holder 10 is arranged in the interior 9 of the dental milling machine 1. The workpiece holder 10 serves to hold a blank 15 and fix it in such a way that unintentional displacement of the blank 15 is prevented during machining. This enables precise machining of the blank 15.

[0025] As in Fig. 3As shown, the workpiece holder 10 is mounted on a support 20 of the dental milling machine 1. In a preferred embodiment, the workpiece holder 10 is pivotably mounted on the support 20 about a pivot axis 21. The workpiece holder 10 extends from its first end 22 to its second end 23. The workpiece holder 10 is pivotably mounted on the support 20 at both its ends 22, 23. The workpiece holder 10 is operatively connected to an electric motor (not shown), in particular a stepper motor, wherein the electric motor causes a pivoting movement 24 of the workpiece holder 10 about the pivot axis 21.

[0026] As in Fig. 3As shown, the workpiece holder 10 comprises a support 11 and an adapter 12. The adapter 12 is arranged on the support 11. The workpiece holder 10 includes at least one clamping device 13. In the present embodiment, two clamping devices 13 are provided. The clamping devices 13 are designed to clamp the blank 15 against the adapter 12. The blank 15 is preferably held directly between the adapter 12 and the clamping device 13. It is also possible to provide only one clamping device 13, or more than two. The clamping devices 13 are preferably attached to the adapter 12. Alternatively, the clamping devices 13 can also be attached to the support 11. A screw connection 14 is provided for attaching each clamping device 13. In an alternative embodiment of the dental milling machine 1, it may be advantageous to design the clamping device 13 to be attachable to the adapter 12 or the support 11 without tools.In such a design, the clamping device 13 can be attached, for example, via a quick-release clamp, an eccentric lever or the like.

[0027] In Fig. 4The adapter 12 is shown. In this example, the adapter 12 is designed as a blank 16 and is therefore in a first state 17. In this first state 17, the adapter 12 has not yet been milled by the dental milling machine 1. The adapter 12 is preferably made of a plastic. It may be advantageous to manufacture the adapter by injection molding. The machining forces occurring during the milling of plastic are significantly lower than those for a metal material. The adapter 12 extends from its first end face 62 to its second end face 63. In the present embodiment, the adapter 12 is arc-shaped, with the concave side of the adapter 12 being an inner surface 65 and the convex side of the adapter 12 being an outer surface 64. Furthermore, the adapter 12 comprises a top surface 60 and a bottom surface 61, which are connected to each other via the end faces 62, 63, the inner surface 65, and the outer surface 64.

[0028] How Fig. 4 As shown in the preferred embodiment, the blank 16 is designed as a semi-finished product and comprises several pre-fabricated openings 26, 27, 29 as well as functional contours 30, 31. The adapter 12 thus includes at least one opening 27 through which the adapter 12 can be screwed to the holder 11 on its underside 61. The underside 61 therefore forms a receptacle 66 for connection to the holder 11. An internal thread (not shown in detail) is provided in the opening 27. In the preferred embodiment, the internal thread is a threaded sleeve cast into the blank 16. In the present embodiment, three such openings 27 are provided for connection to the holder 11. A different number of openings 27 may also be advantageous. Furthermore, the adapter 12 includes two additional openings 26, each with a thread, through which the clamping devices 13 can be attached to the top 60 of the adapter 12.

[0029] As in Fig. 4As shown, positioning elements 31 are provided on the upper surface 60 of the adapter 12. When the workpiece holder 10 is mounted, the clamping device 13 rests on these positioning elements. Furthermore, a central web 30 is formed on the upper surface 60 of the adapter 13, at each end of which a clamping device 13 rests. When a clamping device 13 is attached to the adapter 12, it is placed onto the positioning elements 31 and, via a guide contour 33 of the clamping device 13, at least partially engages one end of the central web 30. The clamping element 13 is positioned against the central web 30 such that it can be screwed to the adapter 12. This allows for easy assembly of the workpiece holder 10.

[0030] In Fig. 8The holder 11 of the workpiece fixture 10 is shown. The holder 11 has a support surface 40, which serves to support the underside 61 of the adapter 12. The holder 11 extends in an arc from a first end 51 to a second end 52. A support wall 41 is provided on the support surface 40. The support wall 41 is divided into three sections 55, 56, 57. The first section 55 of the support wall 41 is formed at the first end 51 of the holder 11. The third section 57 of the support wall 41 is formed at the second end 52 of the holder 11. The first section 55 and the third section 57 are connected to each other via the arc-shaped second section 56. The first section 55 and the second section of the support wall 41 are oriented substantially parallel to each other. The support wall 41 is preferably oriented perpendicular to the support surface 41.The holder 11 is preferably made of a metallic material, in particular of an aluminum alloy.

[0031] As in Fig. 8 As shown, two stops 42 are provided on the first section 55 of the support wall 41. The stops 42 are designed as projections of the support wall 41. Alternatively, it may also be advantageous to provide the two stops 42 on the third section 57 of the support wall 41. In the non-pivoting orientation of the workpiece holder 10, the two stops 42 define a limit of the adapter 12 with respect to the x-degree of freedom. The second section 56 of the support wall 41 defines a limit of the y-degree of freedom for the adapter 12. The bearing surface 40 defines the limit of the z-degree of freedom. Thus, the orientation of the adapter 12 relative to the holder 11 is determined in all spatial directions.

[0032] To attach the adapter 12 to the bracket 11, the adapter is placed with its underside 61 onto the support surface 40 of the bracket 11. The adapter 12 is then slid against the stops 42 of the first section 55 of the retaining wall 41 and against the second section 56 of the retaining wall 41 itself. For additional positional security between the bracket 11 and the adapter 12, a dowel pin is preferably provided, which engages in the opening 44 of the bracket 11 and in the opening 29 of the adapter 12. The adapter 12 and the bracket 11 can then be screwed together. Through holes 43 are provided in the bracket 11 for this purpose. The adapter 12 is detachably attached to the bracket 12.Furthermore, the fastening method ensures sufficient accuracy in the alignment of the adapter 12 and the holder 11, so that it is unnecessary to reconfigure the workpiece holder 10, i.e., to adjust the x and y coordinates of the workpiece holder 10 in the control unit 4. It is also possible to change different adapters 12.

[0033] The arc-shaped design of the holder 11 and the adapter 12 allows machining of the blank 15 on its circumferential side. The blank 15 is held in the arc-shaped workpiece holder 10, enabling the milling tool to machine the circumferential side of the blank 15 without colliding with the workpiece holder 10. The arc-shaped design of the workpiece holder 10 and its swivelling capability increase the effective working area of ​​the dental milling machine 1.

[0034] As in Fig. 3As shown, the workpiece holder 10 is connected to the carrier 20 via two shafts 53. At least one of the two shafts 53 is driven by the electric motor to swivel the workpiece holder 10. As shown in Fig. 8 As shown, a recess is provided at both the first end 51 and the second end 52 of the bracket 11, forming a hub 50 for connection to the shafts 53 of the support 20. The hubs 50 are screwed to a support element 54 of the support 20. Preferably, the bracket 11 is positively connected to the shafts 53 in the pivot direction 24, for example via a tongue-and-groove connection or a dowel pin.

[0035] As in the Figs. 4 and 5 As shown, in the first state 17 of the adapter 12, all openings and contours of the adapter 12, which serve for the alignment and fastening of the holder 11 and the clamping means 13, are already pre-machined. Only one contour 35 for receiving a blank 15 ( Fig. 6The adapter 12 is not formed in its first state 17. It is to be manufactured in the dental milling machine 1 as follows: The adapter 12 is to be attached to the holder 11 as described above. A variety of different manufacturing programs for completing the adapter 12 are preferably stored in the control unit 4. The operator selects a manufacturing program that is directed at the corresponding blank 16 and specifies the receiving contour 35 desired by the operator. The operator starts the manufacturing program, causing the dental milling machine 1 to perform the milling operation on the blank 16. A receiving contour 35 is then milled onto the adapter 12. The receiving contour 35 is milled into the inner surface 65 of the adapter 12.

[0036] Upon completion of the milling process, the adapter 12 comprises a receiving contour 35 and is thus in its second state 18, as shown in Fig. 6The receiving contour 35 is formed on the inner surface 65 of the adapter. The receiving contour 35 consists of a base wall 37 and a projection 38 formed on the base wall 37. Both the base wall 37 and the projection 38 are formed on the inner surface 65 of the adapter 12. The base wall 37 extends from the underside 61 to the top surface 60 of the adapter 12. The projection 38 abuts the underside 61 of the adapter 12. The base wall 37 extends from the adapter 12 to the top surface 60 of the adapter 12. In the exemplary embodiment, the receiving contour 35 is arcuate, in particular semicircular. This allows circular blanks 15 to be received in the workpiece holder 10. In the preferred embodiment, the projection 38 extends along the entire base wall 37 of the adapter 12, i.e., from the first end face 62 to the second end face 63.It may also be advantageous to provide several projections 38 instead of a single projection 38, which extend only over partial sections along the base wall 37 of the adapter 12.

[0037] Naturally, the receiving contour 35 can be adapted almost arbitrarily to the operator's requirements or to the counter contour of the blank 15 to be received. For this purpose, the corresponding production program stored in the control unit 4 must be selected. Alternatively, a production program can also be created by the operator.

[0038] Finally, the clamping devices 13 are to be screwed onto the top surface 60 of the milled adapter 12. The clamping device 13 comprises a clamping contour 39. The clamping device 13 is arranged on the adapter 12 such that the clamping contour 39 projects beyond the base wall 37 of the adapter 12. To secure the blank 15, it is preferably clamped between the projection 38 of the adapter 12 and the clamping contour 39 of the clamping device 13, with contact against the base wall 37. Figures 10 and 11 ). For this purpose, the screw connections 14 must be tightened. As in Fig. 9 As can be seen, the clamping devices 13 rest on the positioning elements 31 of the adapter 12. This reduces the contact area between the adapter 12 and the clamping device 13, thus ensuring that the clamping forces are transferred to the blank 15.

[0039] By milling the adapter 12, additional calibration of the dental milling machine 1 is unnecessary. The mounting contour 35 for holding the blank is milled into the adapter 12, thus defining the position of the workpiece holder 10 in the dental milling machine 1. The control unit 4 of the dental milling machine 1 therefore knows the exact position of the workpiece holder 10, as this corresponds to the position of the contour programmed for milling.

[0040] In Fig. 12 An alternative 16' blank disc is shown. The 16' blank disc differs from the 16' blank disc according to the... Figures 4 and 5The difference lies in the fact that the inner surface 65' is not curved like the outer surface 64. Rather, the inner surface 65' is flat. Thus, the first end face 62 transitions directly into the inner surface 65', which then in turn leads into the second end face 63. The advantage of this embodiment of the blank 16' is that any desired receiving contours 35 can be milled into the blank 16. Such receiving contours are not limited to circular shapes but can also be polygons or freeform contours. The increased flexibility regarding the design of the receiving contours naturally results in a higher material removal rate.

[0041] As in Fig. 13As shown, a machined form of the alternative blank 16' can be an adapter 12' with three individual projections 38 on the base wall 37. The projections 38 are not connected to each other. The projections 38 form a three-point support, thus ensuring secure fastening of a blank 15 or a comparable workpiece. Of course, other geometries for the adapter 12 may also be suitable.

Claims

1. Method for setting up a workpiece receptacle, with a dental milling machine (1), wherein the dental milling machine (1) has a workpiece receptacle (7), wherein the workpiece receptacle (7) comprises a holder (11) and an adapter (12, 12'), wherein the adapter (12, 12') is fastened to the holder (11), wherein the workpiece receptacle (10) comprises at least one clamping means (13), wherein the adapter (12, 12') is a blank (16, 16') and is milled over by the dental milling machine (1) in such a way that a receiving contour (35) for receiving a blank (15) is formed on the adapter (12, 12'), characterized in that the clamping means (13) is designed to clamp the blank (15) against the adapter (12, 12').

2. Method according to Claim 1, characterized in that the at least one clamping means (13) is fastened to the adapter (12, 12'), in particular after the adapter (12, 12') has been milled over.

3. Method according to Claim 1 or 2, characterized in that, when machining a blank (15), the blank (15) is held between the adapter (12, 12') and the at least one clamping means (13).

4. Method according to any of Claims 1 to 3, characterized in that the adapter (12, 12') is formed from plastic, in particular from injection moulding material.

5. Method according to any of Claims 1 to 4, characterized in that the holder (11) is formed from aluminium.

6. Method according to any of Claims 1 to 5, characterized in that the adapter (12, 12') is held detachably on the holder (11).

7. Method according to any of Claims 1 to 6, characterized in that the holder (11) has at least one lateral stop (42) for abutment of the adapter (12, 12').

8. Method according to any of Claims 1 to 7, characterized in that the holder (11) and the adapter (12, 12') are aligned with one another by way of a dowel pin.