Electronics Forum | Tue May 22 17:21:43 EDT 2001 | davef
BGA require placement accuracy of only 0.3mm (�12 thou), compared with a required placement accuracy of 0.08mm (�3 thou) for fine pitch devices. Even with this level of misalignment, plastic BGA self-center / self-correct during reflow due to symmetr
Electronics Forum | Thu Nov 18 19:45:26 EST 1999 | Deon Nungaray
Deon Response: Hello Will, Yes, you can reflow a double sided board using 63/37 solder paste on both sides. There are some limitations as far as the mass of the components to reflow the second time. If you have doubts or are concerned that a compone
Electronics Forum | Thu Feb 21 10:13:27 EST 2002 | Vince Whipple
Hi Dave G, This is an interesting problem.. I can only add the following: - Try trimming the pins and see it this helps.. sometimes the decreased surface area will lessen the surface tension enough to minimize the effect of bridging. - As Dave F was
Electronics Forum | Wed Mar 20 20:02:06 EST 2002 | davef
Surfactant. A synthetic detergent made from petrochemicals that lowers the surface tension of water and allows better cleaning in small spaces. Do you have a cleaning issue that requires you to use a surfactant? If so, be aware that you must clean
Electronics Forum | Tue Apr 25 10:42:38 EDT 2006 | TMC
Almost all of the components on the bottom side are passives however, there are a couple of mBGA's and qfp's. I am aware that even if the components on the bottom do get reflowed, surface tension of solder will hold them in place. As far as IC's, w
Electronics Forum | Tue Oct 05 04:01:36 EDT 1999 | Brian
| Hi, | | Help! Could anyone help to enlighten me on this? | | Question: | | If I have a CSP/BGA package of size X by Y and the standoff gap between the component and PCB is Z, What is the maximum allowable Y/Z or X/Z that using a normal water cl
Electronics Forum | Thu Feb 17 11:38:53 EST 2000 | Steve Thomas
We appear to have solved a major reflow process problem (poor quality joints on a 20 mil QFP100...excessive solder left on the lead leg, not much left for a joint) with a design change to the board. We gave ourselves considerably more room for a hee
Electronics Forum | Fri Nov 03 11:08:29 EST 2000 | Phil
Hi there!!! Actually, all mentioned ideas were significantly related to the cause of tombstoning. But, based on what DL said, you have to check the placement of your 0402. Coz, based on experience, i evaluated the different variables for the root
Electronics Forum | Fri Jun 23 14:10:01 EDT 2000 | Chrys Shea
Sounds like the mask to me. Had a similar situation a couple years ago. The mask wasn't fully cured, so it absorbed water that the preheaters couldn't dry out. When it outgassed at the wave, it caused a lot of micro turbulence that broke the surfa
Electronics Forum | Thu Jun 22 12:50:13 EDT 2000 | JAX
Igmar, Although I agree with Chrys that square is good,( Better volumn ) his explanation is not entirely correct. Heres a little insert from automata: With square apertures, solder paste is deposited at the center of the aperture. The center release
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