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SMT electronics assembly manufacturing forum.


SMT process benchmarks??

Kelly Morris

#15501

SMT process benchmarks?? | 10 June, 1998

Does anyone have any info./studies on what the percentage or PPM defect rates are for each part of the typical SMT process. Example: Screen Print = 45% of total defects Component Placement = 25% of total defects Reflow = 20% of total defects Other = 5% of total defects

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Justin Medernach

#15503

Re: SMT process benchmarks?? | 10 June, 1998

| Does anyone have any info./studies on what the percentage or PPM defect rates are for each part of the typical SMT process. | Example: | Screen Print = 45% of total defects | Component Placement = 25% of total defects | Reflow = 20% of total defects | Other = 5% of total defects Kelly, Panasonic put out feelers on this very subject in Japan. They surveyed some major OEMs and contract houses and found that approximately 65% of total defects could be attributed to the screen printing process. I'm not sure of the rest of the break down. Sorry. Regards, Justin Medernach

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Chrys

#15504

Re: SMT process benchmarks?? | 10 June, 1998

| | Does anyone have any info./studies on what the percentage or PPM defect rates are for each part of the typical SMT process. | | Example: | | Screen Print = 45% of total defects | | Component Placement = 25% of total defects | | Reflow = 20% of total defects | | Other = 5% of total defects | Kelly, | Panasonic put out feelers on this very subject in Japan. They surveyed some major OEMs and contract houses and found that approximately 65% of total defects could be attributed to the screen printing process. I'm not sure of the rest of the break down. | Sorry. | Regards, | Justin Medernach Justin's right - the typical number quoted for the source of SMT defects is screen printing: 50-75% I personally think its closer to the 75% side. Reflow should contribute nearly no defects, given the oven, profiling, and monitoring technology avaiable today. I wouldn't dump the remaining 25% on placement, however, unless it was in a very broad sense. Bad component features like lead skew & coplanarity contribute to misplacements, but I don't think the machine should take the blame. Chrys

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Earl Moon

#15505

Re: SMT process benchmarks?? | 10 June, 1998

| | | Does anyone have any info./studies on what the percentage or PPM defect rates are for each part of the typical SMT process. | | | Example: | | | Screen Print = 45% of total defects | | | Component Placement = 25% of total defects | | | Reflow = 20% of total defects | | | Other = 5% of total defects | | Kelly, | | Panasonic put out feelers on this very subject in Japan. They surveyed some major OEMs and contract houses and found that approximately 65% of total defects could be attributed to the screen printing process. I'm not sure of the rest of the break down. | | Sorry. | | Regards, | | Justin Medernach | Justin's right - the typical number quoted for the source of SMT defects is screen printing: 50-75% I personally think its closer to the 75% side. | Reflow should contribute nearly no defects, given the oven, profiling, and monitoring technology avaiable today. | I wouldn't dump the remaining 25% on placement, however, unless it was in a very broad sense. Bad component features like lead skew & coplanarity contribute to misplacements, but I don't think the machine should take the blame. | Chrys

Please don't let me let you forget my favorite cause of solder defect - solder and solder wettable surfaces, aside from the original question. Earl Moon

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Dave Garfield

#15502

Re: SMT process benchmarks?? | 11 June, 1998

Kelly: Glad to see your name on the Forum. I believe I could find some date from my past life if you wish. Please let me know. Dave Garfield

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Dew Lolly

#15506

Re: SMT process benchmarks?? | 12 June, 1998

Earl, You never miss an opportunity to muddy the water do you? ;-)

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Earl Moon

#15507

Re: SMT process benchmarks?? | 12 June, 1998

| Earl, | You never miss an opportunity to muddy the water do you? ;-) Ain't it great? Plus, there's an old favorite song of mine - goes something like this: I'd rather drink muddy water and sleep in a hollow log than to be here in Atlanta gettin treated like a dirty dog -SMT makes a fool out of me. Moonman

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Reflow Ovens thermal process improvement

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