Electronics Forum | Mon Mar 10 02:54:22 EST 2003 | sankar
Dear All, Can you advice on how to use X-Ray system to identify the QFP/PLCC pin open application. Whether at all X-Ray can be used for the above application. If so, what will be the false rejection of the X-Ray system. Regards Sankara narayanan ME
Electronics Forum | Sat Mar 15 00:52:18 EST 2003 | Grant
Hi, We had tomb-stoning on a product, and it was quite severe. We eliminated it by reducing the amount of solder paste on the small passible component pads. We used a 5 thou stencil, with 20% reduction, and it eliminated the problem. Regards, Gra
Electronics Forum | Sun Mar 16 20:46:18 EST 2003 | MA/NY DDave
Hi Good, that is one of the things I see some have done. With paste too thick these little components float too much off, rather than centering. YiEng, MA/NY DDave
Electronics Forum | Thu Mar 20 14:01:34 EST 2003 | MA/NY DDave
Hi I understand that more circular or rounded pads also reduce the effect. I love it when many independent variables can alter the outcome. YiEng, MA/NY DDave
Electronics Forum | Thu Mar 20 14:05:17 EST 2003 | MA/NY DDave
Hi Rene Great, I am glad to see that you are recommending by experience placement control as affected by the pick operation. Neat to see you are also noting a thinner paste deposition. YiEng, MA/NY DDave
Electronics Forum | Thu Mar 27 12:25:14 EST 2003 | kenlchin
additonally, minimizing the rising rate aroud 183'c and decrease the droping rate(near 0.8'c/s) is also a good way .
Electronics Forum | Thu Mar 27 17:29:11 EST 2003 | paul
can any one tell me if you should run the same heat on the same boards no matter what deffrent parts are on the board Should you do a oven profile for every deffrent board or is it the thickness of the board that matters.
Electronics Forum | Thu Mar 27 23:31:18 EST 2003 | MA/NY DDave
Hi I hope I am replying in the correct tread down link. J.Fox is right. Know the Assembly / PWA that you are processing. YiEng, MA/NY DDave
Electronics Forum | Fri Mar 28 04:57:41 EST 2003 | emeto
more heat.But that's not correct!If convection there are air flaws and bare board has lower temperature than a board with high density.When you have elements on board you hava a vortex and the air flaw invreases the temperature.
Electronics Forum | Thu Mar 13 09:23:26 EST 2003 | jrloudenjr
What types of systems/procedures are normally used or followed to allow for scrap percentages typically from a 43,000cph placement machine.
