Electronics Forum | Tue Mar 19 11:54:08 EST 2002 | davef
FORMULA OTHER THAN LxBxZ? - Paste is X% [X=~50] metal by volume. Your paste supplier knows the value of 'X'. HOW TO ACHIEVE A CONSTANT REFLOW PROCESS CAPABILITY? - Buy a capable oven, operate and calibrate it properly.
Electronics Forum | Wed Mar 20 19:58:59 EST 2002 | davef
You based the aperture size on LxBxH. Where did you get the LxBxH? Obviously the thickness of the stencil is kinda fixed. Who gave you the other numbers? Consider searching the fine SMTnet archives for background on aperture design.
Electronics Forum | Wed Apr 03 13:42:49 EST 2002 | Bob
Just one minor point to bear in mind, most stencils have tapered apertures. If you want to get really accurate volumes you will need to work put the volume based on the taper of the walls. Probably going to far but at least you can sound knowledgeab
Electronics Forum | Wed Apr 03 18:31:54 EST 2002 | davef
To date, much of this discussion has focused on determining the volume of solder paste. That is but one piece of the measurement of process capability. The other aspect that needs to be evaluated is: an assessment of the accuracy of the positioning
Electronics Forum | Thu Apr 04 03:20:59 EST 2002 | ianchan
Good points... Thanks everyone. ref back to Mr.Bob's/Dave's observation (not in order) on brick accuracy, position & placement, Stencil apperture geometrical opening, will feedback to my team to brain-storm further.
Electronics Forum | Thu Apr 04 09:22:35 EST 2002 | itempea
What are the normal control limits in the industry, for a well controlled process, using a 6 mils stencil? Should they be different according to the surface finish (higher UCL for ENIG, Im SN, etc, lower UCL for HASL)? Thanks, Ioan
Electronics Forum | Wed Mar 20 06:26:46 EST 2002 | hany_khoga
Thank you Stefan but unluckyly those board have many PTH components so that they can not re-enter the reflow oven. But by the way , are you sure that if we switch off the cooling zone we can find the solder still liquid? Hany
Electronics Forum | Wed Mar 20 09:06:25 EST 2002 | stefwitt
there are a few companies using this method to recycle valuable components and make good money with it. The memory boards in computers i.e. could be build with used components.
Electronics Forum | Wed Mar 20 07:57:30 EST 2002 | davef
Purchase: 7095 - Design and Assembly Process Implementation for BGA's Make every effort to distribute the test pads, because if you keep them massed at the ball, it would be a bijundo kick in the BGA rear section, when all of those pins released.
Electronics Forum | Wed Mar 20 15:18:09 EST 2002 | angiewest
You may want to check out IPC-SM-782 "Surface Mount Design and Land Pattern Standard" http://www.ipc.org Good Luck