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A SMT supplier messed up the reflow process of several PCB, though I have to urgently ship.

As seen on the picture, the reflow temperature was too low and thus the solder did not properly flow on some components.

enter image description here

Is there any ways to re-reflow the boards? The problem is that the flux is dried up / cleaned, and there are too many components to put flux on each pin.

Anyone has experience fixing this?

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  • \$\begingroup\$ How many boards? \$\endgroup\$
    – winny
    Jul 1, 2021 at 9:46

2 Answers 2

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The only way with good quality is to add paste and reflow by hand.

The other way is to richly use spray on flux and reflow again.
A lot of rework will be required anyway to fix tombstoning and shorts.
And you will have to wash the boards afterwards.

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  • \$\begingroup\$ Spray on flux seems like a good bet, I managed to fix the boards by adding flux everywhere, but was quite a mess as some QFN floated on the flux and were not flush to the PCB. \$\endgroup\$
    – Damien
    Jul 1, 2021 at 10:56
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Not really an answer to how to fix it, but you should be checking your contract with the manufacturer (or rather, you should have checked it before). This is their responsibility to fix (hopefully!), be that in redoing the batch or compensation for you in having to negotiate with your client.

If it's really that time critical light the midnight oil, and fix the joints manually. Bear in mind, of course, that this may be at a very different quality to what you had specified. It is much more expensive to deal with returns than it is to put a product out a little later than expected.

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  • \$\begingroup\$ I agree with you, unfortunately the place I'm located does not really have contract enforcement, and doesn't really solve the problem, as even if the supplier fixes them it would take 1-2 weeks including round trip shipping. \$\endgroup\$
    – Damien
    Jul 1, 2021 at 10:54
  • \$\begingroup\$ @Damien - good stimulus to find a decent supplier :) Even if it costs a little more now, it will save you a lot in the future. \$\endgroup\$
    – awjlogan
    Jul 1, 2021 at 11:03
  • \$\begingroup\$ yes, that's the 4th one we are working with. The problem is that we are limited to supplier within the country we are located at, and it's the same story all over again. We cannot manufacture abroad because of customs clearance times that are 2 weeks or more... \$\endgroup\$
    – Damien
    Jul 1, 2021 at 11:19

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