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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


#11080

inspection methods | 11 June, 1999

How are you inspecting pcbs post-reflow, are you inspecting all or sampling. The type of assembly involved would be mainly chip components with a mix of actives and a few 25mil and under pitch. If you sample what are your fault rates looking like. Thanks for the input.

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Dean

#11081

Re: inspection methods | 12 June, 1999

| How are you inspecting pcbs post-reflow, are you inspecting all or sampling. The type of assembly involved would be mainly chip components with a mix of actives and a few 25mil and under pitch. | If you sample what are your fault rates looking like. Thanks for the input. |

Visual inspection, post reflow. Sub .65 mm pitch requires magnification 2.5X or higher. Sampling plan based on complexity of product and kit size.

My fault rates, measured in Defects per Million Opportunity (DPMO) are typically between 30 and 100. This ranges from assemblies with 300 parts to 3000 parts per PCB. Component types 0603 to QFP 304. Typical opportunity for defect per PCB is 2K to 10K! I have one product which peaks at 22,000 opportunities for defect.

Also, I might add I use post solder print inspection 2D and 3D. This has abeen a crucial process addition and has reduced solder defects dramatically. Typically, 60 percent of defects are rooted in the solder print process. (by far the most difficult process to controll!) Inspection is done by machine opeator staff. This instills accountability and ownership over the process. I do not believe in 100% inspection. It is not value added to the process. Some inspection is necessary. Remember, you can not controll what you can not measure.

Dean

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KEVIN SIMPSON

#11082

Re: inspection methods | 18 June, 1999

| How are you inspecting pcbs post-reflow, are you inspecting all or sampling. The type of assembly involved would be mainly chip components with a mix of actives and a few 25mil and under pitch. | If you sample what are your fault rates looking like. Thanks for the input.

Hi we are using A 4pi 5dx system after reflow... works great! pre reflow we are using MVT inspection systems.. I feel Mvt elimenates need to inspect after reflow due to massive drops in our defects|

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PCB X-Ray Inspection

PCB X-Ray Inspection System