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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


second side reflow of MSD parts after wash

Views: 2914

#61460

second side reflow of MSD parts after wash | 24 March, 2010

J-STD-033B.1 Says "For cavity packages in which water may be entrpped, water clean processes after first reflow can be an additional source of moisture. This may present an additional risk, which should be evaluated."

And it talks about derating if over you 30C/60% humidity.

But it doesn't say anything about if the assembly needs to be baked before second side reflow. If the assemblies were left out in ambient past the floor life of the compents they would have to be baked. But our plan is run one side one day, wash them, and put them in the dry cabinent (<1% RH)until running the second side. I would think 5 minutes in the wash followed by at least 16 hours at less than 1% humidity would keep the parts dry enough to avoid MSD issues.

P.S. is anyone else having issues with searching? If I type MSD wash, the post has to have those two words back to back in the post. And if I use the advanced search it returns every post as matching.

reply »

#61461

second side reflow of MSD parts after wash | 24 March, 2010

RE Search: Search can be tricky. Try MSD and wash

reply »

#61465

second side reflow of MSD parts after wash | 25 March, 2010

Thanks I guess I got used to google where the "and" is implied.

I searched various combinations and all I could find were threads regarding the pcb's not the components.

Does anyone bake their boards after wash before second reflow because of MSD concerns?

We have baked boards because they weren't put into the dry cabinent after the first side was done. The operators said they were told "the missing parts for the second side are coming tomorrow". Apparently they were told this four or five days in a row...

reply »

reflow oven profiler

SMT Machines