Method for processing and measuring rotationally symmetric workpieces as well as grinding and polishing tool

• US 7,160,174 B2
• Filed: 06/01/2005
• Issued: 01/09/2007
• Est. Priority Date: 06/01/2005
• Status: Active Grant

• Current Assignee: asphericon GmbH
• Original Assignee: asphericon GmbH
• Inventors: Kiontke, Sven, Kurschel, Thomas, Zschaebitz, Alexander
• Primary Examiner(s): Wilson; Lee D.
• Assistant Examiner(s): OJINI, EZIAMARA ANTHONY
• Application Number:
  US11/141,959
• Publication Number:
  US 20060276107A1
• Time in Patent Office: 587 Days
• Field of Search: 451/8, 451/41, 451/285, 451286-290, 125/13.R, 83/71, 83/74, 833/65
• US Class Current: 451/8
• CPC Class Codes: B24B 13/015 of television picture tube viewing panels, headlight reflectors or the like
• CPC Class Codes: B24B 29/04 for rotationally symmetrical workpieces, e.g. ball-, cylinder- or cone-shaped workpieces

Abstract

A method for processing a rotationally symmetric workpiece, preferably having optically effective surfaces, whose symmetry axis is aligned parallel with the z-axis and which is moveable parallel with the z-axis, using a rotating, rotationally symmetric grinding or polishing tool whose rotation axis is aligned parallel with the y-axis and which is thereby touching the surface of the workpiece by means of a processing surface, the workpiece rotating around its symmetry axis and to a tool for performing said method as well as a method for tactile measuring of such a workpiece. The invention may be used for processing aspheric workpieces having optically effective surfaces, in particular lenses or mirrors that have a non-processable zone, for example a conical bump in the middle of the workpiece.

Claims

1. A method for processing a rotationally symmetric workpiece in a space defined by orthogonal x-, y- and z-axes, the workpiece having a symmetry axis parallel to the z-axis, the method comprising:

rotating the workpiece around the symmetry axis;

moving the workpiece parallel to the z-axis;

providing a rotating, rotationally symmetric tool having a processing surface and a rotation axis parallel with the y-axis;

moving the tool in a plane parallel to a plane defined by the x- and z-axes and at a constant distance in the y-direction from the workpiece symmetry axis, the processing surface of the tool thereby contacting a surface of the workpiece.

2. The method as recited in claim 1, wherein the workpiece includes at least one optically effective surface.

3. The method as recited in claim 1, wherein the tool is one of a grinding tool and a polishing tool.

4. The method as recited in claim 1, further comprising determining, for each x-position of the tool, a y-position at which the processing surface will contact the surface of workpiece and moving the workpiece in the z-direction accordingly.

5. The method as recited in claim 1, wherein the processing surface includes a rotationally symmetric spherical surface section of a virtual sphere, a center of the virtual sphere on the rotation axis of the tool, the spherical surface section being formed asymmetrically relative to a mirror plane disposed normal to the rotation axis and the virtual center is lying outside of a midplane of the processing surface.

6. The method as recited in claim 1, wherein the tool includes a shape of a toroid section disposed perpendicularly to the symmetry axis.

7. The method as recited in claim 1, wherein the tool includes a shape of a thin disk, and wherein the processing surface is a narrow side surface of the thin disk.

8. The method as recited in claim 1, wherein the tool includes a shape of one of a cone and a frustum, and wherein the processing surface at a largest radius.

9. The method as recited in claim 1, further comprising:

providing a caliper moveable parallel with the x-axis and capable of contacting the surface of the workpiece at a point of contact and to measure z-values of the surface; and

moving the caliper in a plane parallel to the x-z plane and at a constant distance in the y-direction from the symmetry axis.

10. The method as recited in claim 9, wherein the moving is performed so as to at least one of acquire a cutting profile and determine a center of the workpiece.

11. The method as recited in claim 10, further comprising calculationally converting an x-position of each point of contact to a related radius of the workpiece.

12. The method according to claim 1, wherein the workpiece has a rough surface and further comprising:

applying a uniformly thick layer onto the rough surface; and

scanning the surface using a caliper.

13. The method as recited in claim 12, wherein the workpiece is rotationally symmetric and wherein the scanning is a tactile scanning.

14. The method as recited in claim 13, wherein the layer is at least one of an adhesive strip or an adhesive film.

15. A method for processing a rotationally symmetric workpiece in a space defined by orthogonal x-, y-, and z-axes, the workpiece having a symmetry axis parallel to the z-axis, the method comprising:

rotating the workpiece around the symmetry axis;

moving the workpiece parallel to the z-axis;

providing a rotating, rotationally symmetric tool having a processing surface and a rotation axis parallel with the y-axis;

moving the tool in a plane parallel to a plane defined by the y- and z-axes and intersecting the workpiece symmetry axis, the processing surface of the tool thereby contacting a surface of the workpiece.