Electronics Forum | Thu Oct 21 14:02:32 EDT 1999 | Ron Costa
We are a contract manufacturer currently building a job with IBM CBGA-255 devices and 20mil QFP's that are close to each other. We use a 6 mil laser cut and electro polished stencil with one to one apertures on the BGA's. The customer is experiencing
Electronics Forum | Fri Oct 22 06:19:42 EDT 1999 | TNT
Ron, if I am reading this correctly the 20mil parts are not having problems on a 6mil stencil. If you increase the entire thickness of the stencil to 8mils, there should not be any issues with the 20mil components. The supports you are using could p
Electronics Forum | Fri Oct 22 03:23:37 EDT 1999 | Brian
I agree with John, but Manko has also published 'Soldering Handbook for Printed Circuits and Surface Mounting' (van Nostrand Reinhold, a little more practical and less strong on the theory of his classic one, which is beginning to date (1st published
Electronics Forum | Wed Oct 20 16:05:47 EDT 1999 | Mark Charlton
I knew this would happen. Someone wants to rework a bad BGA artwork by cutting a trace and adding a wire under a 292p 1.27mm pitch PBGA. Has anyone done this before? What kind AND size wire do you use? How do you hold it in place during the replc
Electronics Forum | Wed Oct 20 15:47:14 EDT 1999 | Shane
I am developing a D.O.E for Surface Mount Adhesives and was wondering if anyone out there had any recommendations on a certain brand. I currently have samples of Loctite 3609, 3615, 3618, Heraeus PD955M and MA-420 by Lord Chemicals. I understand Ci
Electronics Forum | Wed Oct 20 10:49:04 EDT 1999 | Brian
Hi! Stu's method is a half-truth. What it measures is the aggregate of all volatile material with a significant vapour pressure at the baking temperature, not just H2O. Short of very complex methods, it could be complemented by a comparitive measur
Electronics Forum | Tue Oct 19 10:53:14 EDT 1999 | Carol Zhang
Hi, I tried to use high temperature solder (540 - 570F)to connect four spacers on the board. The solder mask around the spacers wrinkled a lot.I can even see a few bulbs around it. I use hot plate and solder rings. After hot plate is heated to appr
Electronics Forum | Tue Oct 19 16:59:58 EDT 1999 | Carol Zhang
Hi, thank you for the idea. I may try solder iron, but it much more slower since I have to solder spacers one by one. a stimpson press is used to press the spacer on the board and the edges of the spacers are rolled. Then we solder the edges to
Electronics Forum | Tue Oct 19 19:25:40 EDT 1999 | Jeff Sanchez
Carol, I think the guys are right about you stand off problem but I want to address the wrinkleing of your masking. Although I think the temps you are subjecting the board to are very high and more than likely creating problems of their own. I th
Electronics Forum | Tue Oct 19 09:12:33 EDT 1999 | John O'Brien
Why use labels? They are expensive, fall off, get mangled, etc. If you directly mark the boards, you'll probably save money, enhance traceability, etc. One major contract manufacturer projects payback at 7 months just eliminating label cost and goin
