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  for Metal Finishing since 1989
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Finest surface finishing

Hi !

I am looking for a process with which I can get surface finish of about 10nm (R rms) on the inner surface of a hollow stainless steel tube of 1 mm , 2 mm inner diameter. Is it possible to get down to that surface level? I would really appreciate your help.

Sach
Student - Fort Collins, Colorado, USA
2005

Check into EDM (electronic Discharge Machining) You may be able to achieve a surface finish close to 10 RMS but this might turn out be cost prohibitive. I would expect that it would take a few passes to achieve this level of surface finish. Grinding is out of the question because of the small size of the feature and even then you would probably only achieve a surface finish of 16-32 RMS.

Bryan Parker
- New Mexico
2005

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Again there is a very expensive method called extrude hone that can achieve a proper end result. On the cheap side, you may want to look into a process called ballizing. That is a basically shoving a solid ball through the ID.

AF Kenton
retired business owner - Hatboro, Pennsylvania
2005

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If I'm not wrong, 10nm is 25.4 times smaller than 10 microinches , So, you are talking really smooth, mirror. You might need to look into lapping with diamond pastes.

Another possibility would be electroforming (EF) over a higly polished mandrel of the required size. Much easier to polish and inspect an outside diameter. EF will replicate the finish. Part material can be high purity nickel or nickel-cobalt alloy (similar to stainless steel).

Guillermo Marrufo
Monterrey, NL, Mexico
2005

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Q. I am looking for a process with which I can get surface finish of 2 µinch = 0.05 µm on the outer diameter surface of 4.75" 4145 H material cylindrical bar.
Is it possible to get down to that surface level? I would really appreciate your help.

S Jagdish
- Singapore
May 30, 2012

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