Electronics Forum | Mon Jul 25 08:56:47 EDT 2005 | russ
In addition to Daves comments. You might want to look at the layer construction to see if the copper is balanced throughout the board.
Electronics Forum | Wed Aug 03 08:15:57 EDT 2005 | ajaydoshi
We do pass board on mesh instead of chain for first side. For second side pass on chain.
Electronics Forum | Fri Aug 12 20:26:27 EDT 2005 | dorklover664
Run on the "mesh" for the first side. Then on the chain of the second. It's a quick fix for a pain in the ass problem.
Electronics Forum | Wed Aug 03 04:33:39 EDT 2005 | aj
if you have enough free space at the edge of the board you could try some titanium supports, I have to use these on some products to prevent warping. Also, in relation to profile and I know there are a lot of variables to consider but is 225 not a b
Electronics Forum | Sun Jul 24 07:03:33 EDT 2005 | davef
Warpage problem causes * MLB constructions (not homogeneous or unbalanced - too resin rich or poor) * Supplier process capabilities (lamination cycles) * Material selections (usually cheap and dirty), etc.
Electronics Forum | Wed Aug 03 14:17:28 EDT 2005 | GS
What about PCB construction?: - CEM (2-3....)? FR4 ?....? - how many layers - what about TG ? GS
Electronics Forum | Fri Jul 22 16:42:50 EDT 2005 | campos
hello all, I�m experiencing problems with "warped" boards after first reflow, some of them i just can�t print side two due to this problem,,is it related only to reflow? i�m using a linear profile (225� peak / 70s time above) with a tin lead paste,t
Electronics Forum | Wed Aug 03 21:20:09 EDT 2005 | Ken
CTE mismatch. X, Y, Z all expand at different rates. Cooling or heating rates will not change this CTE mismatch. Layer counts, power plane ballance, equal run lengths in x-y and copper balance all contribute. Have your supplier evaluate your s
Electronics Forum | Fri Aug 12 22:10:24 EDT 2005 | Mika
I agree with all the prior postings! But I have some additional thoughts about this. If there is a build up of moistures (% humidity) inside the pcb; before you reflow the pcba; then you will have the result out of the oven, just as you described. My
Electronics Forum | Tue Aug 02 23:02:04 EDT 2005 | crishan
Assuming it is not PCB supplier related, here are my thoughts; 1. CHK Component density top / bottom, I am assuming you do bottom reflow first then top. If have alot of heavy comps on bottom it might cause the board to sag in the middle. 2. You hav
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