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  for Metal Finishing since 1989
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Surface finish comparison

We are making circuit board heatsinks from aluminum angle. In order to remove any dings from manufacturing or shipping, we hand lap the surface that conducts heat away from the components with 120 grit then with 200 grit wet sandpaper. We are sending these heatsinks out for quote to a machine shop (our next project requires 112 each of three different versions)and I don't know the surface finish callout to put on the print.

Can you please help me come up with the correct callout? I am thinking maybe 32 or 63 microinches, but I don't have a surface finish comparator gauge to check it against. Should I specify the "Production Method", "Sampling Length", "Other Roughness Values", "Roughness Spacing", and/ or "Lay Direction"?

Todd Swagerty
Product designer - Chico, California, USA
June 23, 2009

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August 4, 2009

Dear Todd,

Viewing your question, its known that your cutoff length should be 0.8 mm and the sampling length depends on your functional requirement.

your production method is not required mostly.

Thanks & Regards

Arunachalam.M
- Coimbatore, Tamilnadu, India