Electronics Forum | Fri Mar 16 07:10:53 EDT 2007 | davef
1 Print paste on a bare board or laminate. 2 Place components in the paste. 3 Gently invert and support the board above a table. 4 At one hour intervals, record the number of components that have fallen from the board.
Electronics Forum | Fri Mar 16 07:16:35 EDT 2007 | chrissieneale
Thanks for that - i now have a starting point! Always the hardest bit. I'll report what i find! Chrissie
Electronics Forum | Mon Mar 19 06:47:36 EDT 2007 | chrissieneale
After a little investigation (with my eyes closed and fingers crossed) how about up to 24 hours?! ?! I think i might have found one of the root causes of my oooooodles of rework.
Electronics Forum | Mon Mar 19 14:24:30 EDT 2007 | jdengler
I have been involved with the evaluation of close to a dozen pastes from 5 manufactures. I never found one that would rest on a board for anything close to 24 hrs and still have acceptable performance. Jerry
Electronics Forum | Tue Mar 20 03:48:06 EDT 2007 | chrissieneale
Already figured i would do that if it came to it - still planning my approach, which will hopefully eliminate this whole 'waiting after pasting' nonsense anyway. Suggestions very welcome though, as it may well get to the test and see stage! Cheers
Electronics Forum | Thu Mar 15 09:58:22 EDT 2007 | KEN
Anyone know which IPC document covers this? Me thinks 6....but want the IPC spec. to back this up.
Electronics Forum | Thu Mar 15 10:28:46 EDT 2007 | cecil
Just askin but why would someone even want to subject an assembly to even 6 reflow cycles? As far as how many cycles that an assembly can be subjected to, wouldn't that be determined my your components?
Electronics Forum | Thu Mar 15 20:49:16 EDT 2007 | davef
There is no IPC document, nor should there be. Look here: http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=48102
Electronics Forum | Thu Mar 15 10:05:41 EDT 2007 | Johnny
Sorry new to this... Question: will I have any problem soldering a resistor network with SAC305 coated leads using a normal leaded wave process besides the normal board thickness issues Thx
Electronics Forum | Fri Mar 16 08:01:53 EDT 2007 | ck_the_flip
SAC coated leads on certain components require more dwell time. If you find that you have top-side wetting issues, slow the conveyor down a bit or increase your wave height, or, a combination of the 2.
