Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Screen washing

#25592

Screen washing | 26 August, 2003

I've got a crazy idea that I think might just work, so I need you guys to shoot it down. We will have an in-line wash with a 24" wide belt in our new facility. I'm thinking we might be able to run our 22" screens through this wash instead of using our screen washer, which is a bit of a maintenace headache. I know we would have to get most of the solder paste off the screen before we ran it through the wash to protect our recirculation system. I think it could work, but what do you guys think?

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#25594

Screen washing | 26 August, 2003

Sounds great.. Id think of the same thing you already thought of raw paste eventually clogging the wash...

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Mike Konrad

#25598

Screen washing | 27 August, 2003

Danger Will Robinson� Danger!

Never mix a post-reflow cleaning system with a raw paste removal application (particularly on an inline cleaning system)!. The paste that comes off a screen contains solder balls that are so small, they will eventually be blasted under high pressure under your populated boards.

Additionally, you will be a candidate for the pump-seal of the month club. Other issues include a discharge (EPA) nightmare, and torn screens (inlines are far too powerful for screens).

The best solution� Continue to use your screen cleaner or buy a new / better one.

Mike Konrad Aqueous Technologies Corporation www.aqueoustech.com konrad@aqueoustech.com

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kenBliss

#25599

Screen washing | 27 August, 2003

Bman

Each area and process has a unique machine for a reason. Professional engineers at the various OEM�s have thought these things through and there are specific reasons why you don't wash stencils in a board washer, bake pizzas in your reflow oven, etc. In addition to Mike Konrad�s answer, you are not saving any labor since you yourself stated that you would scrap all the excess solder off first. Not to mention potential problems with uncleaned apertures. Assuming you have a real stencil screen cleaning machine, it should have one of the several proven technologies to properly clean the stencil and clear any debris from the apertures.

Ken Bliss Bliss Industries, Inc. www.blissindustries.com

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CAL

#25601

Screen washing | 27 August, 2003

BMAN.........Consider yourself shot down. unfortunatly (for you) Mike and Ken are right on the mark.

The root of your problem is the current system you have for stencil wash...Explain what Maintenance headaches you have. Many moons ago I had a Smart Sonic with an evaporator tank. This was by far the nastiest crap!! Our Maintenance team would draw straws to see who would be the lucky one to stick there head in and clean it.

cal

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