Squeegees for Step-Down stencil

Now that is a BIG step.

Stencil type: * A metal squeegee is fine with stepped stencils. * A rubber squeegee is fine with stepped stencils.

Comments on step stencil "keepouts" are: * Use an ample space around the stepped down component pads that is stepped down to allow proper contact with the paste. * If you can accomplish it, placing the step on the board side of the stencil is better when using metal squeegees. * In your case, keep the step 120 [some would argue 160] thou from the pads of the component that is stepped .

Going back to the BIG step comment. Consider reducing the overall thickness of your stencil, while maintaining the 6 thou step.

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I wouldn't recommend a metal squeegee, because if you can't wipe the step-etched area completely clean (that's the problem with metal) you'll have problems with the definition of the fine-pitch (it may stick in the holes). Best is a 70 Shore polyurethane squeeguee, or 90 if you have too much scooping out of the bigger apertures.

Daan Terstegge http://www.smtinfo.net

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Hi

I can image too many images for what your product or your process looks like.

Think about hiring a consultant to come in and really look at things.

YiE, MA/NY DDave

This message was posted the Electronics Forum @

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You want to use a rubber squeegee with as high as a durometer as you can get away with, order two or three sets of blades starting with the softest and then progress up the the hardest, the reasoning behind this is the softer squeegees will wear out quicker while scooping paste out of the aperatures all the while. Always have your squeegees .5 inches wider per side than the outermost aperatures you are printing.

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