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
Electronics Forum | Thu Jun 22 12:06:10 EDT 2000 | Wolfgang Busko
Hi Sal, I assume your homeplates are designed with the peaks towards the componentcenter. I can imagine that due to placement inaccuracy not both sides sit in the same amount of paste and that wetting difficulties prevent same force factors for both
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 | Wed Jun 21 05:14:49 EDT 2000 | Wolfgang Busko
Hi Ivan, J-STD-001C chapter 3.6.2 says temperature should be maintained between 18�C and 30�C and humidity should not exceed 70% and below 30% verification of electrostatic discharge control is advised. This is a wide range and I wouldn�t allow a sw
Electronics Forum | Thu Jun 22 11:09:11 EDT 2000 | C.K.
TYPE of Preheater makes a HUGE difference, as well. Infrared (IR) and convection, 2 of the most common types of preheaters, have very different heat transfer characteristics..... Convection heats your board more uniformly, so you'll see very small
Electronics Forum | Thu Jun 22 12:40:40 EDT 2000 | Boca
Everybody's right! Two concerns are proper preheat for the flux and reduced thermal shock to surface mount components. The stupid er dumb thing is that these can be at odds with each other. The flux vendor usually specs topside temp before wave.
Electronics Forum | Wed Jun 21 10:06:19 EDT 2000 | ehab
I believe the training was just a couple days after the installation. It really depends on how many people will be trained and previous machine programming experience. Programming the machine is not that hard; however, it's time consuming sometime.
Electronics Forum | Fri Jun 16 10:38:33 EDT 2000 | Iain
I have 15 very large backplanes (.156" thick Au plating) that the ground pins of a high density thru-hole connector were not thermal relieved in the artwork. As a result we are unable to solder the 8 pins that connect to the ground plane. We know t
Electronics Forum | Fri Jun 16 11:28:53 EDT 2000 | Boca
Solder 'follows' heat. 1. Preheating is a great idea, use a baking oven to get the whole assembly up to temperature, use the preheaters in your wave solder machine (without wave) to preheat the assemblies ... 2. Or use the biggest soldering iron
Electronics Forum | Sat Jun 17 08:57:23 EDT 2000 | Chrys Shea
A few more tricks to try: - Got a hot air rework machine? You can get more controlled heat on the area and lower the risk of damage to the fab. I never got topside fillets un unrelieve ground planes until I went to convection preheat on my waves.
