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What defect in SMT were cuased by dust contamination?

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#86328

What defect in SMT will be cuased by dust contamination? | 27 February, 2021

Does anyone know what defect in SMT will be caused by dust contamination? What dust level in SMT environment is recommended?

Recently an audit come to factory and ask we must control the amount of dust. Why SMT line need to control the dust level?

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#86376

What defect in SMT will be cuased by dust contamination? | 8 March, 2021

For boards that would need the conformal coating process, you would need to have them as clean as possible; especially the no clean process

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#86382

What defect in SMT will be cuased by dust contamination? | 9 March, 2021

This have been solved by storing the boards right in all places I have worked. You open a pack, label and use. If you collect dust in such a small time window, you should totally start paying for cleaning service of the building. Electronics we build under controlled environment.

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#86386

What defect in SMT will be cuased by dust contamination? | 10 March, 2021

Below list based on my observations.

Nozzle block Sensor block Insufficient issue in printing Solderability issue due to fod

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#86406

What defect in SMT will be cuased by dust contamination? | 15 March, 2021

Thanks for the answer. Did you really find the dust block the nozzle and sensor? By the way, If SMT environment need to control the dust then what size of dust need to be controlled? 0.3um, 0.5um or 10um?

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#86706

What defect in SMT will be cuased by dust contamination? | 25 May, 2021

A certain degree of cleanliness is needed in SMT manufacturing environment but not as overkill as place it in a "clean room" environment...

Yes, dust could cause defect on PCBAs (and there are research papers about it too) but only the ones that's visible to human eyes and need to be plenty accumulated on PCB's surface to do it(or using a PCB that's placed outside for over a few days).... And for that level of contamination unless its a outdoor environment I doubt any indoor environment could reach that circumstances.

for some type of PCBAs need to be conformal coated or likewise they usually under went a cleaning process to remove all the contaminants after soldering.

In my view, a "clean room" level dust control might be necessary for 01005 components, but for 0201 and above? why bother? I spent many years in Mainland China and Taiwan and saw many Factories place their SMT lines in a Clean room environment but most of them are either poorly maintained or they are manufacturing PCBAs that's absolutely no need for Clean room environment. Can't figure out why. ;)

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#87210

What defect in SMT will be cuased by dust contamination? | 21 October, 2021

Hi, It depends on smallest pitch size of your components. For the 0.3 um, 0.5 um, etc. sizes could be mentioned on Clean Room. For example; for ISO-7 standart (Class 10,000) higher than 5um is not acceptable, however 1mm can acceptable to describe as a dust.

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