Electronics Forum | Tue Oct 31 20:42:56 EST 2000 | speedy-tech
Now we are face with tombstoning for component '0402',we have tried many ways,it seems no change,Below is our experient: 1,The thickness of stencil is 0.12mm,and the aperture is circle.the diameter is 0.55mm.The pads size is 0.5*0.6. 2 Ch
Electronics Forum | Thu Nov 02 03:42:49 EST 2000 | CHRIS MAY
Tombstoning primarily occurs due to the fact that the paste may melt and wet the metallized face of the chip earlier or better at one end than the other. This could be due to a difference in heat capacity (thermal shadowing ?) or that one end of your
Electronics Forum | Thu Nov 02 09:45:00 EST 2000 | bierleinb
I would check trace-pad interactions as you may be robbing heat from one of the pads causing uneven heating during reflow. Also, measure paste deposits on trouble parts to see volume depsoted across the pads. You should easily be able to do 0402s w
Electronics Forum | Tue Oct 31 19:56:18 EST 2000 | Massimo
I'm reworking BGA with a "SRT Summit 2000". This machine uses a nozzle of the same size of the BGA to conduct nitrogen to the top of the BGA. When I rework big PBGAs (318PBGA, 388PBGA) I've got shorts at the corners (100% of the times!). I think the
Electronics Forum | Tue Oct 31 01:08:25 EST 2000 | Dreamsniper
Here are some: Printing Speed : 2.5 ips (inch per sec) Stencil Thickness: 10 - 12 mil but the latter is the best. Dots sizes: u can get that from the Forum Archive...I used Dave F's dot sizes recommendation...they are good! Squeegee Blade : use met
Electronics Forum | Fri Oct 27 15:22:08 EDT 2000 | Glenn Robertson
Chris - You are not the first to see this problem. I have seen a similar case on parts from another company. There may be a way to "clean" the parts but I'm not aware of it. Maybe someone else will have an idea. I suggest you ask Motorola h
Electronics Forum | Thu Nov 02 22:05:55 EST 2000 | Dason C
Chris, can we share some more information? I am running Motorola 357 BGA with PN XPC860MHZP50C and the problem for me is a large amount of void (checked by 5DX). I checked the ball surface and found some sketch on every single ball (it may caused by
Electronics Forum | Mon Nov 06 10:52:52 EST 2000 | Glen Mantych
Glenn, we have been fighting perhaps the identical problem for nearly a year on a 1mm pitch BGA, we have performed numerous laboratory analyses of defective joints and virgin parts in an effort to specifically identify the cause of the no-wet joints.
Electronics Forum | Mon Oct 30 14:30:01 EST 2000 | JAX
Why would you want to buy Tooling Fixtures for all of your boards if you only plan on using them for the placement machines. I would think the extra cost, increased timeframe, and trouble of converting all current product would be a deterant. Have yo
Electronics Forum | Fri Oct 27 08:41:28 EDT 2000 | Wolfgang Busko
1) Na, I wouldn�t give my scope out of hand, need it to much. 2) Profiling for that pin is a good thing. I don�t know your oven but some will react to exessive external air flow ( means windows and doors wide open ) with sudden loss of temperature t
