I am trying to do some research as I have many customers who face this issue with their parts falling off the board during the second pass. What has worked for you? Many applications are different with reflow profile and probably different weights of the components but maybe there's a solution out there that has achieved successful retention for many devices where solder and surface tension is just not enough? And also doesn't require secondary process or additional equipment needed?

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    \$\begingroup\$ Don't production houses often use glue? \$\endgroup\$ Commented Jul 10 at 18:35

2 Answers 2

  1. Put all heavy parts on one side of board

  2. Handsolder heavy parts

  3. Use dual temperature solder processes (use a higher temp solder for the one side of the board and a lower temp for the final pass)


As a last resort, if the techniques mentioned by V. Spike don't work for you, you can use glue, typically it's red in colour (perhaps for visibility).

Here is one supplier, there are others such as Loctite.

If you are mixing THT with SMT components on the bottom of the board and wave soldering, the SMT parts will need glue.

The 30ml syringe packaged glue fits automated machines or hand pneumatic dispensers.

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    \$\begingroup\$ THT mixed with SMT can also be done with selective wave process (and appropriate placement rules). \$\endgroup\$
    – The Photon
    Commented Jul 11 at 1:49
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    \$\begingroup\$ @ThePhoton Good point. And THT can be done with paste-in-hole techniques or press-fit. \$\endgroup\$ Commented Jul 11 at 1:56

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