Electronics Forum | Wed Jun 21 22:07:09 EDT 2000 | Jason
We are going to try double sided reflow for the first time. Can we use the same 63/37 paste on both sides? The board also has bare copper pads i'm pretty sure. will this present any challenges? The bottom side has a QFP on it. Should it stay on?
Electronics Forum | Sat Jun 17 09:09:15 EDT 2000 | Chrys Shea
Contact the adhesive manufacturer, or their website. Most adhesive suppliers offer two cure options - one with a belt oven profile and one with a box oven profile. The belt oven is usually a ramp and plateau of 120-150C for approx 2 minutes. The b
Electronics Forum | Wed May 17 13:33:32 EDT 2000 | John Thorup
Absolutely Mike Lets take that one step further and say that almost anything that you use to clean up with will from then on be considered hazardous waste. Wiping rags/pads, the previously mentioned vacuum bags/filters, the piece of cardboard that yo
Electronics Forum | Thu Apr 27 21:04:33 EDT 2000 | Dave F
Ron: Good news: Nicolet makes excellent machines. Bad news: I�m unaware of a machine with the capabilities you seek. * X-ray machines lack of resolution needed in relation to the crack geometries encountered within a high density single material.
Electronics Forum | Thu Apr 27 21:20:38 EDT 2000 | Dean
Here are some pointers to use during your X-ray inspection. Microcracking is virtually impossible to determine with X-ray. However, I suspect you are looking for "hard" opens. Those are much easier to find visually. If using a paste-and-place pro
Electronics Forum | Thu Apr 20 21:45:10 EDT 2000 | Dave F
Wister: Oooo, I understand now what you mean by "an open." Sorry, I was (am) a bit dense. Your hypothesis is reasonable. On the other hand, have you looked at the traditional causes of tomb stoning also? For a defect to be a "tomb stone," it doe
Electronics Forum | Mon Apr 17 19:30:27 EDT 2000 | Boca
All of the above is good stuff. To add, I have seen this several times if the assembly is wavesoldered. Heat from the wave can partially reflow the top side SM solder joints and weaken them. To test, check joint strength before wave and then after
Electronics Forum | Tue Mar 21 20:36:11 EST 2000 | Dave F
Armin: Boca makes some good points about release. So, let me spin this up from a different angle ... SM-782 suggests "full radius corners" as an alternative to the more familiar square corner pads on PLCC, TSOP and QFP. We see both also. We thin
Electronics Forum | Thu Mar 16 10:41:34 EST 2000 | Russ
Are we talking midship SMT or wave soldering? SMT - I have found the best method is not having them (WOW) this can be accomplished through pad design, aperture design, placement accuracy, and profiling, It is my understanding however, that these
Electronics Forum | Fri Mar 17 07:51:49 EST 2000 | Peter Barton
John, I have had previous experience of immersion silver coated PCB's in place of HASL coated type using no-clean processing with little or no problem at all. All of the process parameters were left unchanged. There is a very minor difference in th
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