Electronics Forum | Fri Nov 13 09:55:08 EST 1998 | Chrys
| We are experiencing 'lifting' on one or more sides of a QFP. Poor lead co-planarity has been ruled out by independent tests. Please tell me which of the two remaining failure modes is the most probrable? | | 1. Expansion of gases in vias underneat
Electronics Forum | Thu Nov 19 05:25:07 EST 1998 | karlin
| | We are experiencing 'lifting' on one or more sides of a QFP. Poor lead co-planarity has been ruled out by independent tests. Please tell me which of the two remaining failure modes is the most probrable? | | | | 1. Expansion of gases in vias und
Electronics Forum | Thu May 04 04:29:05 EDT 2023 | abhishek10
we have observed a Field claim in ECU where root cause is Lead lift found in one of the IC. What could be the possible reason for lead lift and how to avoid the same in future. QFP is the Type 1.Checked the Part Library(3-D Check Refernece no.-23
Electronics Forum | Thu Aug 31 18:59:55 EDT 2000 | Brian W.
Our customers use OSP, HASL, immersion tin and immersion gold as board finishes. If I recommend a finish to the customer, it is one of the immersion finishes or OSP. Those finishes have the advantage of a flat surface to deposit paste. HASL has va
Electronics Forum | Fri May 28 07:37:52 EDT 1999 | Steve Cheung
Yes l know this problem keeps cropping up on the forum but l've missed some of the follow-ups. Our problem is that the lifting only occurs on 3% of production so actually detecting an improvement is difficult. We're actually having to inspect 144 p
Electronics Forum | Wed Jun 10 14:48:12 EDT 1998 | Chrys
| | Does anyone have any info./studies on what the percentage or PPM defect rates are for each part of the typical SMT process. | | Example: | | Screen Print = 45% of total defects | | Component Placement = 25% of total defects |
Electronics Forum | Wed Aug 09 15:06:17 EDT 2023 | SMTA-64386426
The first thing I do when looking at a part relative to stencil design, is determine the coplanarity per the data sheet. Ideally your stencil thickness should be equal to, or if needed, greater than the coplanarity. You want the solder paste to com
Electronics Forum | Sat Jul 22 13:20:35 EDT 2023 | shrikant_borkar
Dear Abhishek, I too got the opportunity to investigate this defect Lift lead for SOT. Lead lift in IC, and SOT can occur due to various reasons. Here are some possible reasons for lead lift and ways to avoid them: During the assembly process, mecha
Electronics Forum | Wed Oct 03 09:56:51 EDT 2001 | Claude Tremblay
Hello everyone We have a QFP-308 (0.20" pitch)on a board and we have a lot of opens after reflow. We checked our profil by installing thermocouples on the pads of the component and everythings seems OK. We checked the coplanarity of the leads and it
Electronics Forum | Wed Aug 07 18:25:52 EDT 2019 | slthomas
Normally if the package is defined properly I would expect your machine to place it correctly but we have some parts pushed right down to the pads. If the paste is centered, and the parts are centered, and you have obvious bridging potential coming
