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bead blasting conformal coatings

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#71737

bead blasting conformal coatings | 18 February, 2014

Does anyone do this? We have a small booth and lots of different kinds of media to try. it will be local stripping of coating on components for rework purposes. My main concern is ESD levels and how best to measure this. Any ideas or any papers on best practices?

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#71738

bead blasting conformal coatings | 18 February, 2014

Is there a reason you're considering bead-blasting the conformal coating? It seems like a bit of overkill. Most of the cc that I've used over the years either has a solvent that will dissolve it, or will dissolve with heat. Heat has been our go-to method...melt through the cc with an iron during the rework process.

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#71739

bead blasting conformal coatings | 18 February, 2014

Paralene, Paraxylene, or other vacuum deposited coating will require this method to remove the coatings. UR and Acrylics have solvents, as Rob above has mentioned.

Plastic bead media and wheat chaff are ones that I know have been used for Paralene removal.

If you discover anything interesting in your experiments please post results!

'hege

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#71741

bead blasting conformal coatings | 19 February, 2014

Yeh due to the solvents in the coatings im guessing there is a health and safety risk. Solvent stripping is a lengthy process for the coatings we use and usually means submerging the whole board so not local to the rework.

We have a booth with ionisers and ground straps for the board, a mix of media from walnut shells to Aluminium oxide to try. I will start off with each media to see how it performs and then again with static charge readings. Any other things to consider?

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#71742

bead blasting conformal coatings | 19 February, 2014

These micro ablation stations can be outfitted with air ionizers and you can use less electronegative materials like corn starch as the blast media.

Laser ablation works on parylene and other coatings when on metal surfaces.

BWET

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#73444

bead blasting conformal coatings | 3 February, 2015

This is a late reply, but from my experience a really good removal station is one made by a company called CCRCo. They make a micro-abrasive station that addresses all the ESD concerns. They utilize a reusable media that is really cost effective. The stations also have a UV light incorporated (as most conformal coatings have a UV tracer in them) so that you can see what you are removing. Check out: http://www.ccrco.com/index.html

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