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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Reliability of power module soldering

gwen

#4899

Reliability of power module soldering | 18 February, 2000

We always have big power modules on the board,they are very heavy,so we use the screw to fix the soldered module,then we destroyed the solder joints.If we screw them first, the board can't be wave soldered. My questions: whether we should use the screw, how we improve the power module soldering reliability, and what's the reliability of the poiwer module when the board is used in vertical position,can it drop down?

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Dean

#4900

Re: Reliability of power module soldering | 19 February, 2000

I'm not exactly sure of your problem...but I'll give it a shot.

I assume the screw is on the solder side of the board. If you wave solder the screw the head will fill in with solder. Try a water solouble mask or peelable laytex mask over the screw heads or even kapton tape.

You should avoid applying a mechanical stress (screw torque) to the modules AFTER soldering. Joint fracturing is common in this type of mechanical asssembly.

As far as your last question...can the reliability of the module change when the board is used in a vertical (vs. horizontal ) position. Well, more-or-less impossible to answer without specific knowledge of the device and intended application. Example: does it use active cooling? What is the orientation of heat sink fins?

Dean

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Gwen Z

#4901

Re: Reliability of power module soldering | 22 February, 2000

First I apologize for my poor English writing.

we have no heat sink fins and active cooling with power module. when the board is transported,the vibration of board and power module will shotten the solder joint lifetime. if we just solder it without any mechanical fixation,does its solder joint's lifetime go down faster than other devices?

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