Electronics Forum | Thu Feb 14 17:40:34 EST 2013 | jorge_quijano
PCB Supplier made an EDX anaysis, the found a chemical trapped in the holes, and some burnt burrs, according to what they say this stains are over the solder mask & silk, so they do not affect functionality.
Electronics Forum | Thu Mar 25 20:50:50 EDT 2021 | stephendo
A couple more things. The PCB. What size are the pads? One time a board shop had difficulty putting masking between the pads of a QFP and the pads suffered as a result. When I told them they didn't have to have masking between the pads, the pads w
Electronics Forum | Mon Jan 28 08:07:44 EST 2002 | JohnW
Sorry I keep forgetting you lot are backwards in the old metric system :0) anyhoo, yes IPC, the bastions of right well as long as your board is only 1.6mm thick (sorry 62mils)say that you need 75% min general and 50% on ground planes. I'd like to se
Electronics Forum | Fri Apr 16 13:22:48 EDT 2010 | stepheniii
Have you tried running a few bare boards through the oven? If there is no flux on them and you still get the "stains" then I think you can eliminate the flux as the cuprit. And I've been told that white is the second most difficult solder mask colou
Electronics Forum | Thu Jan 30 15:41:52 EST 2003 | MikeF
The easy part is to determine which parts should be coated. The harder part is making sure the parts that should not be coated do not get coated. I don't even want to think about the amount of labor and materials I've lost due to conformal coat get
Electronics Forum | Mon Nov 01 16:41:58 EST 1999 | Robert Culpepper
Hello Mark, I can�t provide any hands on feedback with 0402 packages but we are using a no clean process with 0603 devices. Here are some parameters which will affect solder balling. Stencil thickness, aperture size, paste viscosity, snap off and bot
Electronics Forum | Wed Feb 01 08:12:04 EST 2006 | Chunks
OK, this is easy. You say HIGH fall out, so I can assume 25 or 50%? If so, run 10 without the heat gun and 10 with. This should show you if the heat gun process is the cause or not. If the relay is a surface mount, hand solder them on. If it's a
Electronics Forum | Mon Feb 08 17:11:04 EST 1999 | chris arnold
| I realize it's been discussed many times before. I need to know your opinions, experience, and knowledge concerning "today's"/latest and best pallet designs, suppliers, and methods for using them more effectively. Earl, Pallets can be extremely u
Electronics Forum | Wed Feb 14 21:14:45 EST 2001 | davef
BGA Shorting 1 Damaged mask in between the BGA pad and via on the substrate. 2 Poor print registration. 3 Poor via segregation from the pads? Are they tented or is there just a dam in between? 4 Review the profile. You can run into a number of p
Electronics Forum | Wed Sep 20 14:19:26 EDT 2000 | Jason Wraight
I am sure that this is a problem that will never be solved, but something that I am seeing in increased numbers. Often refered to as "Black Pads". After production, returns from the field coming back with contaminated pads under various components.
