Electronics Forum | Wed Nov 20 18:41:57 EST 2002 | slthomas
Here's part of what I could read: "We evaluated the influence of Lift-off (Fillet-lifting) and the influence of thermal fatigue, in this case on combination between various terminal platings of electronic components and Pb-free solder, Sn-37Pb solde
Electronics Forum | Thu Nov 21 06:36:30 EST 2002 | Ben
I'm doing SMT of lead-free solder BGA on FR4 Ni-Au PCB. The solder paste I'm using is Sn/Ag/Cu and reflow with peak temp at 240C. I found there are voids(1-2) in almost every solder joint(500 micron in dia) under xray. And the void size is violate th
Electronics Forum | Tue Dec 03 07:57:27 EST 2002 | pjc
Price of DEK 248 and MPM UP100 are about the same, $22-36K range. MPM UP100 has programmable squeegee pressure. Precise, repeatable results with less operator involvement. Pressure parameters saved in board program file. DEK 248 has manual microm
Electronics Forum | Sun Dec 08 22:20:39 EST 2002 | grantp
Hi, We have been manufacturing a PCB, however it's been quite tricky to profile, as the edges of the PCB are reflowing before the center of the PCB. I have looked at the design, and there is a small power plane for 2.5 Volt in the center of the PCB
Electronics Forum | Wed Dec 18 15:38:59 EST 2002 | swagner
I have had a similar problem in the past, since I have never worked with a semiautomatic printer there could be a few things I recommend that will not work for you. 1. Make absolutly sure that you have proper support under all of the BGA's. 2. Print
Electronics Forum | Fri Dec 20 04:07:25 EST 2002 | Roger
Although everything that has been said earlier is sound advice for achieving good printing results, I strongly believe your problem is your manual printer and its inability to accurately control the speed at which the PCB separates from the stencil a
Electronics Forum | Sun Dec 22 06:00:54 EST 2002 | Mark
Hi: Your stencil specs are good; Did you check the stencil thickness? It would be worth a ck since there may be an error from the stencil mfr If the paste is not releasing with good stencil specs, these are possible causes: 1 The paste isn't tou
Electronics Forum | Mon Dec 23 16:46:29 EST 2002 | jonfox
If you are using a well maintained chip shooter, you should not see more than 1%-2%, and that is on the high side. Most pick and place machines (depending on what they utilize) with laser, vision, mechanical centering will most likely reject a diffe
Electronics Forum | Fri Dec 27 16:24:01 EST 2002 | Matt Foster
As a project I am trying to design a circuit that transmits data to the 9 pin serial port (RS232) of a standard PC. As a basic start I am trying to make a circuit with 4 ptm switches, when I press switch 1 I would like to display "switch 1" or some
Electronics Forum | Fri Jan 03 12:01:46 EST 2003 | jax
Alot of the companies out there use Standards developed internally, centered around there paste, equipment, and reflow processes. Normally you will see either 5mil or 6mil stencils used for everything in house with the exceptions of specific boards.(
