Electronics Forum | Tue Dec 14 11:08:19 EST 1999 | John Thorup
I think you're on the right track Paul. You didn't mention what type of solder mask was used but I'll presume that it was LPI (liquid photo imagable). If development of the image is incomplete some mask can remain where it is unwanted. Sometimes im
Electronics Forum | Fri Sep 29 13:51:46 EDT 2000 | C. Ortner
We work in a "low" volume high reliability house building mixed tech double sided multi layer CCA's for long lived space applications. Our present problem is inspection questioning every dimple/anomaly on every leadless part(we put passives only thr
Electronics Forum | Wed Jun 14 08:08:56 EDT 2000 | Wolfgang Busko
Hi ji tae, we had a similar problem with QFPs 0,5 pitch processed by one subcontractor. The symptoms we noticed were: - the solderjointshape and wetting looked normal - the surface had a dull gray appearance - by pushing a lead sideways with a tweez
Electronics Forum | Tue Dec 14 11:08:59 EST 1999 | Wolfgang Busko
Hi Paul, you got to find the reason first before any measures can be taken. You have to determine wether it happend somehow at your site or at the boardhouse, you can�t blame them without reason. As long as it is suspected that more of those panels
Electronics Forum | Tue Dec 14 11:13:43 EST 1999 | Chris May
Paul, I have (as many have) come across this problem due to misregistration of resist at the PCB fab. You didn't say if these boards are inexpensive double sided or costly multis. I know this shouldn't make a difference on quality but I would tend t
Electronics Forum | Fri Feb 20 08:44:05 EST 2004 | davef
Lucky guess, eh? [Sorry to blow your theory on bad parts] A 1000 of these boards on the line, ummm. Two ideas to consider: * Increase the conveyor angle [don't get carried away, just keep the angle below 8*]. * Balance the flow of solder so that th
Electronics Forum | Fri Feb 20 12:55:43 EST 2004 | russ
Ah, the old contour wave. I don't really know how to adjust those to get correct backflow to reduce your solder volume. I need to ask why you are worried about this. Do you have a QC requirement in excess of IPC class3 wich allows for this joint t
Electronics Forum | Thu Feb 19 09:02:43 EST 2004 | russ
This is a pretty common sympton when wave soldering chip components. As a note IPC allows for this in wave process. The problem is in the pell off of the wave and you may not be able to fix. Is your back flow off of the wave only present when a bo
Electronics Forum | Thu Feb 19 18:07:57 EST 2004 | davef
We're inclined to buy Russ's stuff about peel from the wave. Look here, but shield your eyes first: [ http://www.thepdfshop.co.uk/ppm/defects/Wave/asp/50.asp ] [A respectful bow to BW for the pix] Could you tell us more about: * Board direction thro
Electronics Forum | Wed Nov 26 11:19:58 EST 2008 | vladig
I don't think you can find any specs on that. As long as a solder joint can not be broken by virtually "blowing over it" any reading on the UTS, or shear strength can be very confusing. You can specify, though that the assembly (joint) should withsta
