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Borderline, unbalanced squuegees

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Borderline, unbalanced squuegees | 6 July, 2009

Hi Everyone,

I am having some problems with pasting. When I print a board i expect the paste deposit to be brick shaped. Nice and square. The porblem is it higher on one side then on the other. And you can tell which direction squeegees were going by looking at print. I read some article that called that problem borderline and is result of unbalanced squeegees. It didn't say how to fix it.

Please can you tell me what unbalanced squeegee means and how to fix it please.

Thank you for your help


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Borderline, unbalanced squuegees | 6 July, 2009

Is this what you're talking about?


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Borderline, unbalanced squuegees | 7 July, 2009

Yes. And thats the problem I'm seeing. Any solutions, advice?

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Borderline, unbalanced squuegees | 7 July, 2009

First, we don't know dip about nonbalanced squeegee. We clipped the above gif from: Solder Paste Printing Inspection: An Inside Look; E Litman, System Engineer, Orbotech; SMT January, 2004

Second, Tekscan talks about a product: I-Scan force and pressure measurement system is a key diagnostic and machine set-up tool for balancing squeegee pressures. [We get nothing from Tekscan for mentioning their name.] We think you should get one and tell us how to adjust the balancement of squeegee blades.

Third, even with what we thought was a balanced squeegee, we have printed paste like "f" in the above graphic when pasting too fast across fine pitch QFP apertures. At the same time, paste printed with the apertures look like "a" above on these QFP.

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Borderline, unbalanced squuegees | 13 July, 2009

1.- If you are using polyurethane squegges , they ned to be changed.

2.- Verify your printing parameters of pressure & Speed , It seems that your pressure & speed are high.

3.- If you are seeing excess in one side and insufficiency in the opossite side, you need to check your printer table level.

What kind of paste pinter are you using?


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