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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Excessive dwell time in solder fountain

Views: 3159


DL

#61729

Excessive dwell time in solder fountain | 30 April, 2010

Where do I find data which shows how much dwell time is excessive in a solder fountain when install through hole connectors into a polyimide board.

reply »

#61747

Excessive dwell time in solder fountain | 3 May, 2010

We're not sure that such data is available. What guidelines does your flux supplier provide in soldering with this process?

reply »

#61748

Excessive dwell time in solder fountain | 3 May, 2010

A good guideline is keep it similar to your wave solder process, for example 2-3 sec. This assumes you're preheating the assembly. While polyimide boards are fairly robust at some point you will begin to see copper dissolution - the solder side pad will begin to shrink as the copper is washed away. Extended dwell times will increase intermetallic formation and may also weaken the joint. The chance of measling and delamination are also increased. Polyimide is hygroscopic - a prebake may be a good precaution and could be used as the preheat prior to soldering.

reply »

Hioki Flying Probe Tester

Boundary Scan