Electronics Forum | Tue Mar 16 09:31:21 EST 1999 | Dave Manero
I am looking for the dimensions of the qfp trays. I need to no the center to center as well as the edge to center. I will use this information to program the fuji QP machine for placing 44pin QFP from the tray, or other devices. I can measure this by
Electronics Forum | Thu Apr 22 14:15:35 EDT 2004 | russ
Well so much for being too hot! Try kicking your max temp up to 220, I wouldn't extend the duration however. I would almost start to think that this QFP has a pb free finish. Let us know what happens Russ
Electronics Forum | Tue Mar 16 09:53:27 EST 1999 | Ben Kirk
| I am looking for the dimensions of the qfp trays. I need to no the center to center as well as the edge to center. I will use this information to program the fuji QP machine for placing 44pin QFP from the tray, or other devices. I can measure this
Electronics Forum | Thu Aug 12 18:43:49 EDT 1999 | Wayne S.
Hello Having a problem with bridging on 20mil pitch qfp, only on the lead groups where squeegee goes over width of apertures. Using MPM sp-200 semi-auto, chem-etch stencil, 9-10mil width opening 100 durometer blade. Getting "tails" on deposits. Trie
Electronics Forum | Thu Apr 15 16:07:37 EDT 2004 | barry
Hi there all, we are having problems with 2 qfp devices. grainy poorly reflowed solder joints. One 100 pin .5mm pitch, and one 64 pin .5 mm pitch . Both of these devices have a thermo pad on the back of them (pad area soldered to back of device)which
Electronics Forum | Fri Apr 23 12:47:29 EDT 2004 | barry
I have increased my peak to 220, and Flow is better, but it still not quite a good fillet all around. The solder tends to kinda "bunchup" at the toe of the lead. If part is Pb free, would this affect adhesion and or flow?
Electronics Forum | Fri Apr 16 08:49:07 EDT 2004 | Chris Lampron
Hi Barry, Your best course of action is to perform a thermal profile and determine exactly what the times/temps are in these locations. Try to match your profile to the recommendations of your solder paste. (Time between 130-160, Time over 183 and m
Electronics Forum | Thu Apr 22 12:27:47 EDT 2004 | barry
I placed thermo's at 2 of the problem devices. Soak (time 150 to 180) 100 sec. Time above 180 =80 secs with 208 deg. peak. The solder appeared to flow at these pads, but little to no adhesion to the joint.Total time in oven was 5 min. All other joint
Electronics Forum | Thu Apr 15 17:06:08 EDT 2004 | russ
What are your temps at the locations that you are having trouble with. We cannot tell anything by the zone settings of an oven. We need max temp, how long above liquidous etc.. a lot of times this symptom is due to too long of a soak at too high o
Electronics Forum | Sat Apr 17 17:08:22 EDT 2004 | finepitch
Russ has a hint by saying "too long of a soak at too high of a temp or being in reflow for too long/hot". I think the board should stay in the oven for 3-4 minutes, spending 60-90 seconds of which during reflow. in order to stay in the oven for 3 m
