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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

PPM for SMT Placement



PPM for SMT Placement | 4 May, 2000

SMT Placement ppm = # of defects*1E6 /(Qty boards * number of components per board)

is the above ppm formula for placement defect correct? How about in your company? what method you are using? We are planning to implement SPC on our SMT Lines, any idea or advise on where will we start, and how to effectively monitor our SPC ?

thanks in advance

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Travis Slaughter


Re: PPM for SMT Placement | 8 May, 2000

A common formula and perhaps more telling would be 1 defect for each solder joint and each part. For example a 1206 resistor could be 3 defects, a QFP128 could be 129 defects.

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