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Electropolished part dimensional tolerance

My project includes modification to pharmaceutical vial handling equipment which will include the manufacture of new machine parts destined to serve above the product line inside of a class 100 barrier system. Subject parts will be machined from 316L. 10-12 Ra is desired after electropolishing for cleanability. Final dimension tolerances for certain part features is desired at ±.0005 inches for certain overall dimensions (.1875 inches up to 13.5000 inches) and for certain hole sizes (.2500 inch diameter up to 1.0000 inch diameter).

Question:

1) Does electropolishing remove sufficient material to upset ± .0005 tolerancing? How much should I allow for removal? How close can tolerances realistically be held after electropolishing of precision parts?

2) How to write the electropolishing specification in order that my electropolishing vendor succeds in maintaining critical ±.0005 dimensions?

Thanks for your assistance!

Dave Heinrich
a pharmaceutical company- Kalamazoo, Michigan, U. S. A.
2003

Electropolishing will normally yield approx. 50% improvement in Ra, so your starting finish needs to be fairly good. The metal removal is usually a ten thousandth. Holes can be plugged and features masked as necessary to hold a tighter dimension.

Dan Weaver
- Toccoa, Georgia
2003