Abrasive tool making process – material – or composition – With carbohydrate or reaction product thereof
Patent
1989-12-04
1992-08-18
Kisliuk, Bruce M.
Abrasive tool making process, material, or composition
With carbohydrate or reaction product thereof
5116577, 51284R, B24B 1306
Patent
active
051387980
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method and to apparatus for polishing an optical component.
The conventional technique for fabricating optical components such as lenses or mirrors comprises successive operations of providing a blank, grinding it down, and then polishing it. The blank is made by machining using a bell-shaped tool with abrasive diamonds. Grinding down and polishing are both performed by means of a polisher and an abrasive. Grinding down is a roughing-down operation which is relatively quick and easy to perform, but polishing is a very long and expensive operation on which the optical quality of the component depends entirely.
At present, polishing is characterized both by the age and primitiveness of the machines used and by the subtlety of the skilled know-how of the personnel performing this operation. Traditional polishing machines essentially comprise a lathe having a vertical axis of rotation on which the component to be polished is fixed, a polisher coming into contact with the surface of the component to be polished, said polisher being supported in its center by a ball-and-socket connection and being driven through orbital motion while bearing against the surface to be polished, and mechanical linkage means for positioning the polisher and for generating its motion.
The polishing method consists in interposing an abrasive powder of determined grain size and a wetting liquid between the polisher and the component to be polished. Abrasive feed, the type of polisher, its diameter, the bearing pressure applied thereto, the position, amplitude, and speed adjustments of its orbital motion, and the adjustment applied to the rotation of the lathe all constitute polishing parameters. It is necessary to proceed with considerable caution given that the localization and amplitude of polishing operations are not exactly controlled. Thus, polishing is performed by alternating operations of verification and of removing a very small amount of material. If too much material is removed from any given point, and the measurement to which successive polishing operations were converging is exceeded, then the entire surface of the optical component needs to be started over. This is a permanent danger, and each time it happens cost is considerably increased.
In order to avoid these drawbacks, specialized personnel undertake a very large number of verification operations and between these operations polishing operations are performed during which only a small portion of the surface defects (in excess) in need of correction are, in fact, removed.
As a result, if a 600 mm diameter mirror is being polished to an accuracy of 1/8 of a wavelength, for example, then about 400 hours of machine time and 150 hours of specialized personnel time are required. During the finishing period alone (which lasts for 10 to 15 days), two to three verifications of the surface state of the component are required each day. About 40 successive polishing operations are required in order to reduce the amplitude of surface defects from 5 microns to 1/8 of a wavelength.
This multiplication of individual polishing operations is due to them being voluntarily limited to an effectiveness of about 10% during each individual operation, such that about 90% of the amplitude of the defect remains to be treated. Clearly, if this effectiveness could be improved without risk, then the number of operations required for polishing optical components could be considerably reduced, thereby reducing their cost.
In addition, if polishing conditions could be mastered, then these operations could be automated.
A particular object of the invention is to provide a method and apparatus for polishing optical components and satisfying these requirements.
The invention thus provides a method of polishing an optical component by means of a polisher mounted on a motion-generating and guiding support, the method being characterized in that it consists in transferring parameters defining individual polishing operations to the polisher and its support, and in quantifying t
REFERENCES:
patent: 3769762 (1973-11-01), Mayo
patent: 4592684 (1986-06-01), Baker
patent: 4598502 (1986-07-01), Lombard
patent: 4768308 (1988-09-01), Alkinson
patent: 4956944 (1990-09-01), Ando
NTIS Technical Notes, No. 12, Part F, Dec. 1985, (Springfield, Va.), Programmed Optical Surfacing Equipment, p. 1375.
Applied Optics, vol. 21, No. 3, Feb. 1, 1982, Optical Society of American, (New York), R. A. Jones: Segmented Mirror Polishing Experiment, pp. 561-564.
Optical Engineering, vol. 22, No. 2, Mar./Apr. 1983, Society of Photo-Optical Instrumention Engineers, (Bellingham, Wash.), R. A. Jones: Computer-Controlled Polishing of Telescope Mirror Segments, pp. 236-240.
Applied Optics, vol 26, No. 12, Jun. 15, 1987, Optical Society of America, (New York, NY), G. Doughty et al.: Microcomputer-Controlled Polishing Machine for Very Smooth and Deep Aspherical Surfaces, pp. 2421-2426.
Bertin & Cie
Kisliuk Bruce M.
Marlott John A.
LandOfFree
Method and apparatus for polishing an optical component does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for polishing an optical component, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for polishing an optical component will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1239788