Electroplishing to remove embedded abrasives in 304 Stainless Steel?

[ligo]

Hello, We have about 100 canisters made from 304 SS that have been abrasively ground, sanded and/or polished. The exact type/brand/composition of abrasives used is not in our control since an outside vendor is doing this part of the work. They will undoubtedly use whatever they have at hand.

As a final step we need to remove any embedded abrasives (and any binder used to hold the abrasives together) from the 304 SS. We think that electropolishing may accomplish this, but I can't find any information on how successful we should expect this to be. Does anyone have any data on how well elecroplishing will remove embedded abrasives? If the embedded abrasives go deeper than .0005" will electropolishing get them out? Any source of hard data on this would be greatly appreciated.

These canisters will be going in a high vacuum environment in which there are instruments that are very sensitive to even the smallest contamination. Particularly from any out-gassing of any compounds that might have gotten embedded with the abrasives. Before going into the vacuum the canisters will also undergo ultrasonic cleaning and vacuum baking for 48 hours to remove any remaining surface contamination, and then handled only in a class 100 clean room environment.

thanks for your help

 

[unclesyd]

Personally Ive never seen abrasives embedded in SS under the conditions you describe.
My quick answer would be to get one of what you consider the worst cases and one of not so bad and have them electropolished polished.

One approach is to contact people like Extrude Home who have a multifaceted approach to surface finishing.

http://www.extrudehone.com/index.php

May I ask how you are determining that you have embedded abrasives?

 

[israelkk]

To my experience electropolishing itself will not remove embedded abrasives or binder. To my opinion you need to use a mechanical cleaning such as fine mesh glass beads or aluminum oxide grits blast. Use low pressure to avoid too much removal of base metal if wall thickness is important. Then use passivation or electropolishing.

 

[ligo]

I don't have any experimental evidence to show that there actually is embedded materials of any type or size. Nor do I know how or it was decided that any possible embedded materials are a problem. Typically our machining requirements do not allow any type of abrasive removal of material. This requirement was specified long before my time, and I'm having trouble tracking down its origination and original justification.

The follow-on question will be the same for 6061-T6 AL plates that have been sanded.

thanks

 

[Compositepro]

I think the vacuum bake you mention is designed to do exactly what you are asking about.

 

[ligo]

I would concur that it certainly seems as if the vacuum bake should take care of any volatile compounds, and even potentially cause embedded abrasive to loosen and fall out. but I need data to back up any claims, and I don't have access to parts to verify.

 

[unclesyd]

One thing you might try is run them through an ultrasonic bath. I would use a worm alkaline type cleaner in the bath and followed by a rinse the dip in an non ultrasonic acidic bath. Rinse with good water and then give them a rinse in an ultrasonic bath with deionized water.

 

[ligo]

Before vacuum baking, all of these canisters will go through 2 ultrasonic cleanings at about 140F using Liquinox or Citranox as the cleaning agent. The spec. also states that the canisters are to free of oils and contaminants before ultrasonic cleaning. Thus the idea behind the electropolishing is to get them into the ready to be cleaned state.