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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


PCB defects

Views: 4620

#79465

PCB defects | 13 December, 2017

HI all. Recently we have been experiencing some PCB defects and so far it appears on a particular pcb. Components in areas, and the areas appears to be random, have shifted, skewed components. Most of these components, it appears the solder has flowed up the component leads, but not on the pads. This problem occurs 1 or 2 out of maybe 20 pcb's. Any suggestions? thanks

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#79475

PCB defects | 14 December, 2017

Where in the process these defects appear?

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#79476

PCB defects | 14 December, 2017

When the board is populated on the second side, and after reflow, components are shifted, skewed with solder flowed on the leads of the components and not on the PCB land.

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#79478

PCB defects | 14 December, 2017

Now,

if before reflow everything looks fine, something happens in the oven. As it is second side, I would ask if there are parts close to edges or very tall parts on the first side that might be getting in contact with something in the oven? In my opinion, your problem will be caused by board jumping or getting in contact with something in the oven.

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#79481

PCB defects | 14 December, 2017

May be run a board on open cover and see what is going on.

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#79482

PCB defects | 14 December, 2017

We did check for oven clearance thinking the same , but there is plenty clearance. We have however found that the problem was on several lots of PCBs. We ran a fresh lot and problem went away. There appears to be some kind of contamination on the PCbs from the supplier causing the solder to not flow on the pads. Even when reworking the PCBs, some pads were difficult to get good flow. We are going to send them back for evaluation. Thank you for your input.

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#79506

PCB defects | 20 December, 2017

I am also interested to know. Please update me. Thanks!

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#79526

PCB defects | 26 December, 2017

Hi,

We have develop a solution, called ASD, to online analyze and detect of real problem on SMT production. If you want more information, you can send me an email: alexeis@proventustech.com. Also, you can read about us and our solution on the website: wwww.proventustech.com.

Best Regards, Alexei

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#79551

PCB defects | 4 January, 2018

Hello, I have experienced the same problem. It is a problem with your PCB manufacturer. If the paste goes away from the pads it is most likely PCB problem. How long does it take to produce from top to bottom side? The longer it takes, the worst the problem can get. You have to show your PCB maker these problems and fix them together.

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