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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Manually Adding Paste at Screen Printer

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#72538

Manually Adding Paste at Screen Printer | 7 August, 2014

Good morning everyone! I'm searching through tech sheets and equipment manuals to determine the recommended paste thickness on the stencil during operation. We use a MPM momentum screen printer using SAC305 paste. Board isn't too complex; one QFP, couple SOIC-8's, and smallest compponents are SOD-523 diodes.

What my ultimate goal by determining the recommended thickness of paste is to increase the manual "add/check paste" frequency of the machine. I emptied a jar of paste and ran 15 cycles yesterday and had about 14mm thickness across my paste, ran 15 more and still 14mm. By then the paste started to leave the squeegee so I kneaded the paste back to the center.

Any suggestions would be appreciated.

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#72552

Manually Adding Paste at Screen Printer | 11 August, 2014

paste should be 12-16mm in diameter. If your squeegee is the same size as your roll you shouldn't observe any difference for 15boards. Adding paste is important when you run hundreds and thousands of PSBs.

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