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Michel (NPI Engineer)
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Join Date: Mar 2008
Posts: 2

SPI's mold surface call-out equivalent for "Diamond Polished Optical Clear"

03/27/2008 3:52 PM

I'm looking to complete a plastic injection part dwg., and I would like to find an equivalent SPI mold surface finish call-out (i.e. A-1, C-3, etc...) instead of using words such as "Diamond Polished Optical Clear".

Michel
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garyceng
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Location: North East Pennsylvania
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Good Answers: 7
#1

Re: SPI's mold surface call-out equivalent for "Diamond Polished Optical Clear"

03/28/2008 12:17 AM

A #4 microfinish is considered a mirror polish for molds to obtain an opticaly clear molded part.

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plaasteek
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Join Date: Feb 2008
Location: Made in USA
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#2

Re: SPI's mold surface call-out equivalent for "Diamond Polished Optical Clear"

03/28/2008 10:20 AM

The best way to define the mold finish would be to specify "SPI A-1, Optically Clear Mold Finish." Now, this could also be specified as "SPI A-3" because it depends upon the material being molded, as with polycarbonate. It is best to check with your material suppier for the finish they recommend for their product to be molded. Too high of a finish can create material sticking and other molding problems.

I included a reference chart where you can visually see the recommended SPI finish for the material being molded.

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Michel (NPI Engineer)
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Join Date: Mar 2008
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#3
In reply to #2

Re: SPI's mold surface call-out equivalent for "Diamond Polished Optical Clear"

03/28/2008 1:03 PM

Thank you. The chart was extremely helpful.
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