PCBgogo

Electronic Project Engineer's Best Partner!
X****Liu
How to "toast" double-side PCBs on these conveyor ovens?
299 1 Apr 10.2019, 09:42:31

I am looking into small conveyor reflow ovens and trying to solve a puzzle how to reflow components on both sides.   
Is there any trick how to do this?    

  • Comments(1)
Upload a photo:You can only upload 1 files in total. Each file cannot exceed 2MB.Supports JPG, JPEG, GIF, PNG, BMP
Browse
Submit
header
A****min

Apr 13.2019, 11:46:13

Well,the PCB goes through the conveyor reflow oven twice, e.g. each side is reflowed separately.
Once a side has been soldered the solders surface tension will hold the parts to the PCB when going through the second time upside down. 
If large/heavy parts are on one side then this side is done last so it never goes through upside down.
If both sides have large/heavy parts then glue dots are sometimes used to hold heavy parts to the PCB and stop them falling off.
The bottom side of the PCB is not soldered while going through the machine upside down.
If parts are on the bottom side when going through the machine then they have already been soldered previously.
Only molten solder has enough surface tension to hold the parts on when upside down. Solder paste does not, they would all fall off or tombstone if you tried to do it.
(It might be possible to glue every part to the underside and then solder both sides at once, but this isn't normal practice.)  

Approval(0) Reply

Submit
Share the Project