Method for achieving length accuracy of diamond turned parts
A temporary part is mounted onto the chuck of the diamond turning machine. A diamond turning tip of the diamond turning machine is used to form a reference surface on the temporary part, registering a baseline for a motion control system of the diamond turning machine. While the temporary part remains mounted to the diamond turning machine, a workpiece is mounted onto the temporary part, and the diamond tip is controlled relative to the reference surface to diamond turn a surface profile on the workpiece. Because the baseline established by the reference surface compensates for positional variations from mounting parts directly onto the chuck of the diamond turning machine, the length of the workpiece can be shaped to a designated length with a high degree of accuracy.
1. A method for diamond turning a workpiece on a diamond turning machine comprising a chuck and a diamond tip installed on the diamond turning machine, the method comprising:
mounting a temporary part onto the chuck of the diamond turning machine;
using the diamond turning machine to control the diamond tip to diamond turn a reference surface on the temporary part;
while the temporary part remains mounted on the chuck and the diamond tip remains installed on the diamond turning machine:
mounting a workpiece onto the temporary part; and
using the diamond turning machine to control the diamond tip relative to the reference surface to diamond turn a surface profile on the workpiece.
2. The method of claim 1 , where the diamond tip diamond turns the surface profile to achieve a specified thickness for the workpiece.
3. The method of claim 2 , where the workpiece is diamond turned to a thickness tolerance of 1 μm or less.
4. The method of claim 1 , where diamond turning the reference surface on the temporary part comprises:
diamond turning a recess into the temporary part, a bottom of the recess serving as the reference surface.
5. The method of claim 4 , where mounting the workpiece onto the temporary part comprises:
mounting the workpiece into the recess, the recess also laterally positioning the workpiece.
6. The method of claim 4 , where the recess has a bottom and sidewalls, the bottom is substantially perpendicular to an axis of rotation for the diamond turning, and the sidewalls are substantially parallel to the axis of rotation.
7. The method of claim 4 , where the recess has a bottom and sidewalls, and the temporary part further includes corner relief features at a junction of the bottom and sidewalls.
8. The method of claim 4 , where the diamond tip diamond turns the surface profile to achieve a specified thickness for the workpiece, and the recess has a depth that is less than the specified thickness.
9. The method of claim 1 , further comprising:
before diamond turning the surface profile on the workpiece, diamond turning a cut surface on a side of the workpiece that is opposite the surface profile, where mounting the workpiece onto the temporary part comprises mounting the workpiece with the cut surface of the workpiece contacting the reference surface of the temporary part.
10. The method of claim 9 , where:
diamond turning the cut surface comprises, while the temporary part remains mounted on the chuck and the diamond tip remains installed on the diamond turning machine:
mounting the workpiece onto the temporary part with the side opposite the surface profile facing the diamond tip; and
controlling the diamond tip relative to the reference surface to diamond turn the cut surface on the workpiece.
11. The method of claim 10 , where mounting the workpiece onto the temporary part further comprises cleaning the reference surface and the cut surface after diamond turning the cut surface and before mounting the workpiece onto the temporary part.
12. The method of claim 9 , where diamond turning the cut surface is performed using a different diamond tip, on a different diamond turning machine and/or without the temporary part.
13. The method of claim 9 , where diamond turning the cut surface further comprises diamond turning a recess into the cut surface, the method further comprising:
filling the recess with filler material to planarize the cut surface before mounting the workpiece with the cut surface of the workpiece contacting the reference surface of the temporary part; and
releasing the filler material after diamond turning the surface profile.
14. The method of claim 13 , where diamond turning the surface profile on the workpiece cuts through the workpiece to the filler material in at least one location to produce a hole in the workpiece.
15. The method of claim 13 , where diamond turning the surface profile on the workpiece cuts through the workpiece to the filler material to separate the workpiece into two or more pieces.
16. The method of claim 13 , where the filler material is a curable, soluble material.
17. The method of claim 1 , where the chuck is a vacuum chuck, the temporary part is mounted onto the vacuum chuck by suction from the vacuum chuck, the temporary part includes a vacuum port that extends the suction to the reference surface, and the workpiece is mounted onto the temporary part by suction from the vacuum port.
18. The method of claim 17 , where diamond turning the temporary part further comprises diamond turning a spiral groove on the reference surface connected to the vacuum port, the workpiece mounted onto the temporary part by suction through the spiral groove.
19. The method of claim 1 , where the temporary part and the workpiece comprise a poly(methyl methacrylate) material.
20. The method of claim 1 , where the workpiece is mounted onto the temporary part using at least one of magnetic attraction, electrostatic attraction, and interference fit.