Electronics Forum | Tue Nov 02 09:29:21 EST 1999 | Wolfgang Busko
Hi Kevin, you could use a fixture for supporting the assembly. I think it�s a common solution for thin PCBs. For the design you could search the archive there are some tips on this already ( search for support, fixture, pallet ). hope this helps Wo
Electronics Forum | Sun Oct 31 23:58:54 EST 1999 | John A.
Do both sides of that board contain larger IC's and other large components or just one side?? If just one side contains large components, try running the side with the smaller components first, and then run the other side last. If that doesn't work
Electronics Forum | Sun Oct 31 19:34:43 EST 1999 | Pat Copeland
I am currently placing aprox. 95 to 100 1206 size ferrite beads onto a pcb and having difficulty solding these parts. They appear to be soldered when the board comes off the reflow, but you can flic the parts off by hand. We thought they were contami
Electronics Forum | Fri Oct 29 04:51:11 EDT 1999 | Wolfgang Busko
Hi Eom, no matter what size the crack is it�s a no-no and you should take any precaution to avoid this cracking. Ask your vendor if you are not sure which moisture level applies for your part. Follow the recommended handling specifications for moistu
Electronics Forum | Thu Oct 28 13:36:14 EDT 1999 | Bart Smith
I am a design engineer and have a circuit board design with a 292 pin BGA on it. The board manufacturer is experiencing a failure rate of about 2.8% on the BGA device due to soldering problems. This is my first experience with BGA. How does the 2.
Electronics Forum | Fri Oct 29 05:23:00 EDT 1999 | Wolfgang Busko
Hi Bart, that�s much to high. If that would happen to me my boss would tear my head off. For improving the yields you must find the cause for the soldering problems. What are the symptoms? What could be the cause for the symptoms? Could be design pr
Electronics Forum | Thu Oct 28 09:16:38 EDT 1999 | DaveH
Michael, You can try contacting National Training Center for Microelectronics in Pennsylvania. They are a "for fee" training center, but may be able to supply you with some basic information that would assist your research as a student. Try e-mailing
Electronics Forum | Wed Oct 27 19:50:59 EDT 1999 | chris
Hi What is the possible cause of non-wetting of solder paste to the gold land pad. What we observed in the surface of the non-wet pad is an organic FM, and using FTIR we found out that it is a flux. It is possible that the cause of non-wetting is
Electronics Forum | Thu Oct 28 09:25:35 EDT 1999 | Dave F
Chris: Typical non-wetting causes are: * Poorly controlled soldering process * Incorrect material * Surface contamination * Insufficient preheat * Misapplied solder mask * Shadowing Without intending to insult you, all of the causes of non-w
Electronics Forum | Thu Oct 28 20:45:38 EDT 1999 | chris
Hi Dave, We suspect that the organic FM causes the non-wetting problem. FTIR analysis confirm that the FM is a flux residue. Dave we only used FTIR to detect organic contaminants, we also used SEM/EDX to determined the elemental composition of the
