Method for polishing

• US 20070173176A1
• Filed: 03/30/2007
• Published: 07/26/2007
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: asphericon GmbH
• Original Assignee: asphericon GmbH
• Inventors: Kurschel, Thomas, Kiontke, Sven
• Granted Patent: US 7,854,645 B2
• Time in Patent Office: Days
• US Class Current: 451/5
• CPC Class Codes: B24B 1/00 Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
• CPC Class Codes: B24B 13/012 conformable in shape to the optical surface, e.g. by fluid pressure acting on an elastic membrane
• CPC Class Codes: B24B 13/06 grinding of lenses, the tool or work being controlled by information-carrying means, e.g. patterns, punched tapes, magnetic tapes

Abstract

A method is disclosed, whereby a reduced wear of the polishing tool and a reduced duration for the polishing process may be achieved and also free form surfaces and non-rotating workpieces may be polished. The above may be achieved whereby the surface of the tool actually in contact with the workpiece lies off the tool axis. The invention further relates to a method for polishing a surface of a workpiece, via a tool rotating about a tool axis, whereby the workpiece, at least in one region of the workpiece surface has a contacted surface which is part region of a surface for machining, which for its part is at least part of a polishing surface of the tool, whereby the tool axis intersects the polishing surface.

Claims

1. A method for polishing a surface of a workpiece via a tool rotating about a tool axis, whereby the workpiece is contacted in at least one region of the workpiece surface by a respective momentarily contacting surface that is a subarea of a surface for machining, which is at least part of a polishing surface of the tool, whereby a tool axis intersects the polishing surface, the method comprising:

adjusting a position of the tool such that a center of the tool'"'"'s respective surface momentarily contacting the workpiece is off the tool axis; and

tilting the tool about an axis distinct from the tool axis, wherein a relative angle between the tool axis and a local surface normal of the workpiece is adjusted in the contacted area, and wherein the tool is moved translatively along at least a part of the workpiece surface, and wherein a relative angle is being continuously modified at least in sections in the course of the translative motion along the workpiece surface.

2. The method according to claim 1, wherein the tool is tilted about an axis that is perpendicular to the tool axis.

3. The method according to claim 1, wherein the relative angle to be adjusted is determined based on data associated with the workpiece and/or the tool.

4. The method according to claim 3, wherein the relative angle is determined based on a respective position of the tool relative to the workpiece.

5. The method according to claim 4, wherein the relative angle is determined based on a surface normal of the workpiece in the contacted area of the workpiece surface in this position.

6. The method according to claim 3, wherein the relative angle is determined on the basis of a polishing surface normal of the surface of the tool which is in momentary contact with the workpiece surface, respectively.

7. The method according to claim 3, wherein the relative angle is determined on the basis of a removal that is to be achieved from the workpiece surface.

8. The method according to claim 1, wherein a tool with a planar polishing surface is tilted about an axis that is distinct from the tool axis, based on a surface normal of the workpiece in the contacted area, wherein the tool axis is collimated with the surface normal and the tool is parallely translated to a workpiece surface in the contacted area.

9. The method according to claim 8, wherein the amount of the translation is determined based on a removal that is to be achieved.

10. The method according to claim 1, wherein the workpiece rotates about a workpiece axis.

11. The method according to claim 10, wherein rotary motions of workpiece and tool are reversely directed, such that a relative speed between the workpiece surface and the polishing surface, in the range of the respective momentarily contacting surface, is increased.

12. The method according to claim 1, wherein the tool is pressed against the workpiece surface.

13. The method according to claim 12, wherein the contact pressure is controllable.

14. The method according to claim 12, wherein the contact pressure is generated by compressed air.