Mandrel reusability in precision replication of ZnS conformal domes

Jitendra Singh Goela; Joel Askinazi; Barry Robinson

doi:10.1117/12.439167

7 September 2001 Mandrel reusability in precision replication of ZnS conformal domes

Jitendra Singh Goela, Joel Askinazi, Barry Robinson

Proceedings Volume 4375, Window and Dome Technologies and Materials VII; (2001) https://doi.org/10.1117/12.439167
Event: Aerospace/Defense Sensing, Simulation, and Controls, 2001, Orlando, FL, United States

Abstract

Recently precision replication of flat, spherical and aspheric surfaces was demonstrated in ZnS by a chemical vapor deposition (CVD) process. Two-inch size ZnS parts were replicated successfully down to a fraction of a wave in the visible and finish of 20-180 Angstroms RMS. The replication technology was then extended to produce six best-fit-sphere ZnS corrector elements of diameter 2.4-inch by replicating on Al₂O₃ and SiO₂ coated, highly polished and diamond turned ZnS mandrels. These replicated corrector elements measured an inside surface figure of 0.14-0.27 Angstroms RMS and smoothness of about 41 Angstroms RMS. Mandrel reusability was then demonstrated by replicating on several previously used corrector element mandrels which were minimally refurbished (mandrel surface was cleaned with acetone). These replicas and mandrels measured essentially same surface figure and smoothness after second replication as before. After replication, analysis was performed on a few mandrels, which did not release from the replicas. Cause of this adherence was determined to be presence of 10-20 micron size pinholes in the release coating. Very good replication was achieved on those areas where no pinholes were present. The integrity of the release coating determines the durability of the replication mandrel.

Citation Download Citation

Jitendra Singh Goela, Joel Askinazi, and Barry Robinson "Mandrel reusability in precision replication of ZnS conformal domes", Proc. SPIE 4375, Window and Dome Technologies and Materials VII, (7 September 2001); https://doi.org/10.1117/12.439167

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available