Electronics Forum | Tue Jul 11 12:59:26 EDT 2006 | mattkehoe@sipad.com
We are trying to apply solder to boards with 80 microinches of electro plated hard gold. No components involved, just print 63/37 paste and reflow. The results are very poor on some boards, not so bad on others? Pictures at http://www.sipad.net/thick
Electronics Forum | Wed Jul 12 11:26:12 EDT 2006 | flipit
Hi, I believe you have classic gold imbrittlement here. With 80 microinches of gold you are way over the limit. You can try to reflow longer time and at a higher temperature. The gold does not melt into the solder joint. The gold dissolves into
Electronics Forum | Thu May 26 08:52:42 EDT 2011 | davef
Phil Zarrow wrote a useful paper that could help in evaluating paste. Here read it ... Evaluating Solder Paste � Not An Option Contributed by Phil Zarrow of ITM an Independent SMT consulting firm With soldering being the dominant source of assembly
Electronics Forum | Tue Jun 01 05:17:16 EDT 2004 | Alistair MacAdam
I am currently looking at the volume of paste being deposited on a PWB 2.4mm thick with a 0.25mm tolerance. I am looking for information on PWB variation and a MPM AP25 series printer, and can the volume of paste be controlled on varing PWB thickness
Electronics Forum | Tue Jun 01 07:26:55 EDT 2004 | johnwnz
Alistair, your paste deposit is controlled by a few things: Stencil thickness Squeegee pressure Squeegee speed Print gap in 99 out of 100 applications for paste printing you would have a print gap of 0 i.e. on contact printing where the PCB is in fu
Electronics Forum | Tue Jun 01 10:15:29 EDT 2004 | davef
We agree with John about his comments on the controlable factors relating to your printer, but we'd add that paste formulation and mesh are also contributors to nice looking bricks.
Electronics Forum | Mon May 07 16:07:05 EDT 2012 | davef
Start with targets based on the stencil thickness (for height) and stencil thickness times the aperture size (for volume). * Set reasonable upper and lower control limits (+ 25% and –25 % of the targets, for example). * Next, check the printer set-u
Electronics Forum | Mon May 07 10:42:09 EDT 2012 | saju86ece
Hi, I need one clarification about solder paste printing height tolerance. How to define and fix the solder paste height tolerance after screen printing for inspection purpose. Currently we are using 5mils thickness of stencil, in that we are gave
Electronics Forum | Tue Jun 01 12:48:49 EDT 2004 | pjc
AP25 can handle warped boards to a degree. I also depends on the board clamping system on the machine. There are three avbl. First is Universal Vacuum box, second is dedicated tooling with vacuum and third is Y Snugger tooling that does not use vacuu
Electronics Forum | Thu May 08 18:21:13 EDT 2014 | jorge_quijano
Hola, We are about to start building a new PCBA using a LGA, we have not used such components in the past, is there any recomendations you can provide me? I've found some articles saying that stencil thickness is the key, what is your experince usin
