Electronics Forum | Wed Jun 25 08:58:02 EDT 2003 | cyber_wolf
I need something that is very thin so I can screen print while the fingers are protected. We have tried cleaning the fingers prior to shipment, but our customer tells us that even alcohol leaves enough residue to cause problems.
Electronics Forum | Mon Aug 02 11:21:29 EDT 2004 | sforman1
Use MicroCoat Technologies UV cure solder mask. will leave PCB absolutely clean. used in many PCB solder/wirebonding apps. http://www.m-coat.com
Electronics Forum | Mon Aug 02 11:44:49 EDT 2004 | jbabson1
If you do wire bond before printing, Photo Stencil (www.photostencil.com)can help you design a stencil with relief on the pwb side for the wirebonding.
Electronics Forum | Tue Nov 30 16:04:04 EST 2004 | fcox
When you say something went wrong in the screening process, do you mean that the paste is splashed (prior to reflow)?
Electronics Forum | Tue Nov 30 17:32:37 EST 2004 | russ
If you are lucky, you might be able to chip the solder off the fingers with an Exacto knife and then polish it up with a pink eraser. This does work if the solder on the fingers isn't wetted very well. Russ
Electronics Forum | Tue Jun 28 09:13:46 EDT 2005 | russ
It appears that the reflow profile was incorrect or the paste was in bad shape on these boards from what I can see. I personally have never seen a board finish cause this symptom.
Electronics Forum | Tue Jun 28 10:41:57 EDT 2005 | GS
I am not an expert but just for my understanding: - solder paste used ? NC ? other ? - reflow in Air or N2 ? - temp ramp up before soack (�C/second) ? Tnks GS
Electronics Forum | Tue Jun 28 13:23:56 EDT 2005 | Bob Gilbert
Matt, Try a cooler profile by simply speeding up the conveyor by 10%. The difference may be the temperature the pads are reaching between the HASL boards and the Au boards. Are they the same thickness?
Electronics Forum | Tue Jun 28 17:38:13 EDT 2005 | mdang
We got the same problem. To solve it, we have to tint the pads first and do the normal reflow process. It works but take a lot of time to tint the pads. Any thoughts? Thanks, -Michael
Electronics Forum | Tue Jun 28 18:40:36 EDT 2005 | Bob Gilbert
Matt, Try putting a soldering iron to a pad to see if you get reflow. If it reflows, your oven is too cool. If no reflow, your oven may be too hot. Regards, Bob
