Electronics Forum | Fri Sep 24 10:57:18 EDT 1999 | Earl Moon
| Hi Folks: | | We've been having bridging problems on our fine-pitch QFP's, despite thorough inspection of paste height, volume, and placement accuracies....profiles look good also. | | The bridging is happening after coming out of reflow...one la
Electronics Forum | Mon Jan 04 11:59:41 EST 1999 | Steve Evers
| Give me your opinions and experiences of SelectX, selective debridging system in the Vitronics Soltec wave soldering machines. | Opinion and (food for thought)?: First let me say that I am not familiar with SelectX. In the past, manufacturing e
Electronics Forum | Wed Sep 01 06:38:37 EDT 2010 | grahamcooper22
Dear Leeg, Generally the faster your print speed the more down pressure you need on the blade to roll the paste and wipe the stencil surface clean. Pastes with higher viscosity need more pressure at slow and high print speeds. Too much pressure cause
Electronics Forum | Thu Feb 17 10:14:40 EST 2000 | Jim N
We bulid many boards with fine pitch on solder side and then wave. We use a wave fixture that is custom for each board. The fixture covers the SMT components and only exposes the PTH lead during the wave process. It requires about .070 to .100" clear
Electronics Forum | Thu Aug 21 09:34:57 EDT 2003 | davef
Woa. The more paste that you put a a BGA ball, the more likely that you'll bridge between balls. Why do you need to compensate for the size variance in BGA balls? How does using a 8 thou thick stencil to compensate for ball size variance? Fine pi
Electronics Forum | Tue Jul 27 07:06:59 EDT 2004 | davef
HASL Thickness: * HADCO DFM manual specifies a nominal thickness of 50-1500uin with an option for 100-1000uin * Merix DFM manual specifies 30-200uin * Our boards (from a major fab) average 500uin with an "as measured" range of 300-800uin Be careful
Electronics Forum | Sat Aug 07 17:27:00 EDT 2004 | celldude
We use ssd on all components, from 0201 to very large fine pitch and bga's. With some very small micro bga's , if there is a problem with bridging, we will tape off the stencil during the ssd process and just use bare pads...along with the solder fr
Electronics Forum | Mon Aug 08 22:32:18 EDT 2005 | adlsmt
If you are using fine lines and tight spacing ENIG may be cheaper than HASL. This is because there is not as much bridging at the board house between traces so they do less touch up. This would probably be even more true with no-lead. We have been us
Electronics Forum | Fri Nov 25 09:31:56 EST 2005 | davef
pyramus, First, search the fine SMTnet Archives for previous discussions on BGA shorts. Second, we're still not clear on the issue. * Is the problem with a BGA? If so, please describe the BGA, including any heat spreader * Is the problem with a uB
Electronics Forum | Wed Oct 31 09:09:35 EDT 2007 | russ
Small waves are fine, biggest problem is the little to no preheat length. This is reason that complex boards cannot be soldered without defects. They also do not handle thick PCBas very well either because of same issue. Most of these "benchtops"
