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Q&As since 1989
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Metallizing plastic diffraction gratings
Q. I am working on plastic diffraction gratings.These gratings will consist of injection molded parts with grooves 5 microns deep. The material will be ABS or polycarbonate. I need to apply a reflective metallic coating to the part. The electroplating process needs to be very controlled because of the tiny groove depth.
Fernando ErismannC&K Systems
1996
A. Hi, Fernando. For low volumes, the easiest and most practical idea is "two-part silvering" where you simultaneously spray silver nitrate [on eBay or Amazon] and a reducing agent onto the grating. The small grooves should be no problem at all. However, you may want to apply it on a spin table to insure full coverage and no air bubbles preventing wetting.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
A. It never ceases to amaze me how this kind of plating is possible at all. The results are nothing short of specular(!). And yet, it is only one of the many challenging, exciting, and rewarding fields in platingdom.
You have to see an operation of this kind to believe it. Plating is the way to make a mold of a surface like this for mass reproduction.
Tom Pullizzi
Falls Township, Pennsylvania
1996
1996
A. Fernando:
Sounds like the processing used to manufacture compact disks is something you should look in to.
CDs are molded from low molecular weight polycarbonate with pits on the order of 0.5um wide and 0.1um deep. These are produced from a photosensitive glass "master" disk from which a galvanic nickel negative "father" is made. A positive "father" is made from additional galvanic nickel deposits. From these "fathers", a "mother" and subsequent "sons" are made in a similar way.
ASM Metals Handbook Vol. 5: "Surface Engineering"
on
AbeBooks
or
Amazon
(affil links)
"Electroplating Engineering Handbook"
by Larry Durney
on
AbeBooks
or
eBay
or
Amazon
(affil links)
The "sons" are used in an injection molding process to produce the disks. The moldings are then metallized (vacuum vapor deposition) and coated with varnish to complete the disk.
You may be able to take advantage of some of these techniques.
Brian CardwellFord Motor Company
Q. Dear Sir,
can I use CD as a diffraction grating for the separating of the ultraviolet ? It is necessary for my greenhouse optimisation.
Best Regards
- Izmir TURKEY
2000
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Diffraction Grating HELLO Thank you for your consideration, - Charlotte, North Carolina 2004 Looking for source of diffraction gratings for art project. William Martin- Thomaston, Maine (2008) Edmund Scientifics and Sargent-Welch have diffraction grating sheets. Good luck. Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey |
I do artwork about Heaven and would be interested in finding out if I can add refraction gratings to my pictures on plastic sheets? As it is we have wonderful time with light coming into our windows in morning and giving us a free lightshow! Would imagines in refraction grating goes patterns to appear? Thanks for any info!
Lee LipeHeavenly Clowns - Paradise, California
September 5, 2008
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