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Vibratory finishing of polyurethane pieces

I have been casting products out of a clear polyurethane for a number of years. I am developing a couple of new products (small -- approximately a 2 ounce cast)that have some minor sanding/finishing needed. To sand and buff these parts out by hand is too labor intensive and I am searching for some vibratory media options to clean these parts up. The material is similar to the clear coat of an automotive finish and is a shore D-80 hardness. The urethane is extremely durable but accepts sanding. I could opt for sand finishing to a dull finish and then topcoating them with a clear but that again becomes labor intensive. Does anyone have any suggestions for a finishing media that would not simply "bounce off" and a subsequent polishing media? Thanks in advance for any suggestions. Joe H

Joe Havian
- Valrico, Florida, USA
2003

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Dear Sir,

We are using centrifugal disc finishing machine for this type materials. This machine can process 50 shore A hardness rubber or PU with ceramic abrasive chips.

Ersan Yurdagulen
- Turkey
2003

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Hmmmmmmm! You know, that is the material that is used to line big mass finishing equipment work chambers. These liners are rigid and do wear but that takes a lot of time. Then again, if you use a high energy centrifugal system with a big, coarse ceramic media, you might achieve the results you are looking for in a reasonable time frame. You have to also remember that this will produce a uniform finish, but outside edges may be effected to a greater extent. If you are interested, send me some samples for processing.

AF Kenton
retired business owner - Hatboro, Pennsylvania
2003