US 6,537,138 B2Granted

Method of grinding an axially asymmetric aspherical mirror

AssigneesRiken, Shimadzu Corporation

InventorsHitoshi Ohmori, Yutaka Yamagata, Sei Moriyasu, Shinya Morita, Katsuhiko Kada, Hidetaka Kira, Hiroyuki Sasai, Masaru Kawata

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Abstract

An electrolytic in-process dressing device 10 is provided with a disk-shaped metal-bonded grindstone 2 with a surface 2a with a circular arc shape with a radius R at its outer periphery and a numerical control device 16. The disk-shaped metal-bonded grindstone 2 rotates around an axis Y, and the grindstone is dressed electrolytically while the device 10 grinds the workpiece 1. The numerical control device 16 is provided with a rotary truing device 12 that rotates around the X axis that orthogonally crosses the axis of rotation Y and trues the circular arc surface 2a, a shape measuring device 14 for measuring the shape of the circular arc surface of the grindstone and the shape of the processed surface of workpiece 1 on the machine, and controls the grindstone numerically in the three directions along the axes X, Y and Z. The numerical control device 16 moves the grindstone in three axial directions and repeats the operations of truing, grinding and measurements on-line. Thus, an axially asymmetrical aspheric mirror with a highly accurate shape and extremely low surface roughness, that can precisely reflect or converge light can be manufactured within a short time with a high accuracy.

Claims5

Dependent claims

A method of grinding an axially asymmetric aspherical mirror, comprising the steps of:

providing a workpiece;
providing a grinding apparatus comprising:
(a) a disk-shaped metal-bonded grindstone rotatable about an axis Y and that has an outer periphery surface that defines a circular arc with a radius R;
(b) an electrode that faces the grindstone and defines a space present between the electrode and the grindstone;
(c) a nozzle disposed to supply a conducting liquid between the electrode and the grindstone;
(d) a power supply device operably connected to apply a voltage between the grindstone and the electrode;
(e) an electrolytic in-process dressing device disposed to electrolytically dress the grindstone while the workpiece is being ground by the grindstone;
(f) a rotary truing device rotatable about an axis X orthogonal to the axis of rotation Y and disposed to true the circular arc surface;
(g) a shape measuring device disposed to measure the shape of the circular arc surface of the grindstone and the shape of a processed surface of the workpiece;
and
(h) a numerical control device operably connected to numerically control the grindstone in three axial directions X, Y and Z;
processing the workpiece by grinding with the grindstone;
truing the circular arc surface of the grindstone with the rotary truing device;
measuring the shape of the circular arc surface of the grindstone and the shape of the processed surface of the workpiece to provide on-machine measurements using the shape measuring device;
and
moving the grind stone in the three axial directions in accordance with the numerical control device, and repeating the steps of truing, processing, and measuring.

13 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/793,421Filed 27 Feb 2001
Priority: JP 2000-0582823 Mar 2000
Published: US 2001/0024934 A127 Sep 2001
Granted: 25 Mar 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

B24B 49/04
According to the instantaneous size and required size of the workpiece acted upon, the measuring or gauging being continuous or intermittent:…
B24B 13/06
Machines or devices designed for grinding or polishing optical surfaces on lenses or surfaces of similar shape on other work; Accessories…
B24B 53/001
Devices or means for dressing or conditioning abrasive surfaces: involving the use of electric current
B24B 53/08
Of profiled abrasive wheels: controlled by information means, e.g. patterns, templets, punched tapes or the like