Electronics Forum | Thu Nov 21 05:44:07 EST 2002 | kcorrin
We produce several boards with reflowed components on top and bottom. We are finding the solder has wetted to the leads but did not flow completely to the end of the lands. Several factors/causes?: 1) Board warping but paste deposits look good. 2) Mo
Electronics Forum | Mon Feb 12 12:33:24 EST 2007 | SJ
There are several ways to inspect solder paste after deposition. Defects will range - too much paste, not enough, misaligned, bridged, smeared, etc. Some sceen printers have 2D inspection imbedded, otherwise a standalone system for paste inspection
Electronics Forum | Wed Jul 29 20:53:44 EDT 1998 | Dave F
| Howdy all- | Does anybody have any experience with solid solder deposits as an alternative | to paste deposits? I have heard many good things, but do board fabricators have | the technology to do this? Where can I get more information on ho
Electronics Forum | Mon Feb 03 23:49:00 EST 2003 | Dreamsniper
Hi, Has anyone who's using vapor phase process able to help me troubleshoot tombstoning? I raed about uneven forces during reflow due to misalignment, pad design, paste volume deposition unevenness due to dirty stencils, worn stencil printer parts s
Electronics Forum | Wed Feb 07 07:45:50 EST 2007 | jax
Water soluble residues probably won't cause instant failures. The failures are most likely caused by excess paste being deposited on the center pad of the QFN. The excess solder keeps the part from sitting down in reflow and increases the possibility
Electronics Forum | Thu Jul 17 15:12:18 EDT 2008 | slthomas
To quote a regular here, "Are you sure your washer is set up correctly?" :P He's a WS junkie. This is a really common problem and is discussed here often. Mid chip solder balls (solder beads) are almost always the result of too much paste being dep
Electronics Forum | Fri Jul 08 09:30:35 EDT 2011 | kahrpr
Check that your pick and place machine is not pushing the part too far in the paste and squeezing the paste off the pad. Your profile could need modifying. In the case of the profile the solder paste can slump off the pads before turning into a liqui
Electronics Forum | Tue Jun 26 16:43:19 EDT 2001 | CPI
Yes a 6 mil solder deposite will reduce to approx 50% of it's original size. Does this happen on only 1 BGA? Is the BGA that its happening on have smaller balls than the others, what I'm getting to is, are you sure you are depositing the proper amo
Electronics Forum | Tue Aug 25 08:51:16 EDT 1998 | Justin Medernach
| | | Hi, | | | Does anyone has experiences in reflowing Ceramic BGA and found solder wicking ? Solder wicking has the syndrome that solder being wick from the pad and ended up in the leads. | | | We have rule out the possibility of not printing any
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
