Electronics Forum | Thu Aug 24 13:10:57 EDT 2000 | Dave F
How do these factors affect paste selection? How does paste selection affect nozzle slection?
Electronics Forum | Thu Aug 24 13:31:41 EDT 2000 | Dr. Ning-Cheng Lee
For 20 mil pitch applications, two important properties to evaluate are (1) dispensing volume consistency, (2) slump performance. As to the dispensing equipment, positive displacement will be the better choice for better consistency. Nozzle size is v
Electronics Forum | Wed Aug 23 09:16:42 EDT 2000 | Dave F
Dr. Lee: How do the metallurgical properties of solder change during a second reflow. Please provide detail on this phenomenon.
Electronics Forum | Wed Aug 23 16:32:19 EDT 2000 | Dr. Ning-Cheng Lee
"Dibasic" means a molecule containind two acid functional groups, such as carboxylic acid. The inductive effect makes the dibasic activator more active than mono-basic activator.
Electronics Forum | Thu Aug 24 13:13:42 EDT 2000 | Dr. Ning-Cheng Lee
Inductive effect is the electron attraction force between chemical moieties. Inductive effect in flux activator would stabilize the dissociated organic acid, thus enhance the acidity, therefore increase the flux activity.
Electronics Forum | Wed Aug 23 09:09:43 EDT 2000 | Dave F
Dr. Lee: Some say flux lowers the surface tension of solder. Others argue against that point. What is the flux mechanism that lets solder move more freely?
Electronics Forum | Wed Aug 23 09:05:38 EDT 2000 | Dave F
Dr. Lee: In using environmental screening tests to assess solder joint reliability, what are the effects that make low temperature vibration effective in screening of poorly wetted solder connections? What temperature and vibration profile are effe
Electronics Forum | Thu Aug 24 13:38:23 EDT 2000 | Dave F
It seems that sceening at -20�C and using a vibration profile similar to the one you mentioned does a good job of high-lighting defective solder connections on assembled boards, but not affecting good connections. Why is this happening? In there a
Electronics Forum | Wed Aug 23 08:50:04 EDT 2000 | Dave F
Dr. Lee: We had a discussion on the forum recently and I wanted to get your input. What is the best method(s) for elimating (reducing) no-clean solder paste flux from splattering on gold interconnect fingers on a PCA?
Electronics Forum | Thu Aug 24 13:04:28 EDT 2000 | Dave F
How does flux selection fit into the mix of factors affecting splattering? Do various flux formulations splatter more than others?
