Title:
PREPARATION OF MAIN TOOL FOR REPEATED MANUFACTURE
Document Type and Number:
Japanese Patent JPS5570550
Kind Code:
A
Abstract:
A method of making a master replicating tool having a predetermined negative aspherical profile from which aspherical profiled optical elements can be made, comprising machining a blank of a hard, non deformable siliceous material with a cutting tool in a one stage machining operation to produce substantially the predetermined profile, coating the surface so produced with a layer of nickel or nickel based alloy, machining the nickel or nickel based alloy to produce the predetermined profile with the cutting tool and protecting the surface by applying a layer of an inert, scratch-resistant material thereon. Hand figuring the blank after machining is avoided. The scratch-resistant layer is thin and can be between 500 A and 5000 A thick. This layer is applied by vapour deposition and is preferably vacuum deposited vitreous carbon. The blank is machined to produce the substantial predetermined profile to within the limits determined by the fracture planes of the siliceous material which are produced during the machining operation and these fracture planes may be less than 20 mu m for ceramic materials.
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Inventors:
HARII HOUDEN
Application Number:
JP14288579A
Publication Date:
May 28, 1980
Filing Date:
November 06, 1979
Export Citation:
Assignee:
PHILIPS NV
International Classes:
B24B13/01; B24B13/00; B24D3/00; B29D11/00; C03C17/00; C03C17/36; C04B41/00; C04B41/52; C04B41/89; G02B3/02; (IPC1-7): B24B13/00