Electronics Forum | Fri Apr 17 14:08:44 EDT 1998 | Earl Moon
| Currently I am in the buisness of soldering bare die to the top surface of a copper heat sink. Is any one else | have some exprience in this process that can help. We heat a copper slug through a contolled atmosphere, place a preform then a bare
Electronics Forum | Mon Mar 30 12:55:16 EST 1998 | Justin Medernach
| Hi, | We have encountered de-wetting issues with gold plated components( SMT LEDs ). | The problem comes and go and we yet to locate the root cause ( process, component or solder paste etc ). | The rest of the components on the boards are not havi
Electronics Forum | Mon Aug 27 10:58:44 EDT 2001 | Ryan Jennens
Steve- We had the same trouble with 0805 Panasonic film caps. We had some tombstoning and open solder joints (non-wetting). We found two problems...like you, we changed our pad design to meet their recommendation. Also, they were able to suppl
Electronics Forum | Tue Feb 19 15:59:55 EST 2002 | pjc
Surface tension is a likely cause. Surface tension is a negative wetting force. You may have a solderability problem. Be sure your flux is properly activated according to the flux mfg. top side board temp. specification. When surfaces to be soldered,
Electronics Forum | Thu Jun 13 06:08:57 EDT 2002 | edahi
guys thanks for the suggestions... DaveF, *Changing paste EricD: Yes we are considering that as a point. Because I believe the paste we are using are in syringe packaged and designed for dispensing. We are using an Indium SMQ75 paste and current
Electronics Forum | Wed Jul 31 08:23:49 EDT 2002 | mcm4me
221C). 2D vision can very effectively detect % pad coverage, I use it on my DEK and this customer has an MPM which I also believe to be capable. Here is another fact, when the customer uses Brand X solder paste the defects due to what they call pad
Electronics Forum | Fri Aug 30 00:47:53 EDT 2002 | TLe
Dave, you did not understand my problem right. We don�t get paste on the PCB in the printing phase of process. I have seen also poor wetting on OSP, as you descriped, but that is very unusual. I think generally OSP is better than gold/nickel if spea
Electronics Forum | Fri Jan 24 22:50:51 EST 2003 | MA/NY DDave
Hi Again Distance is tough, besides far less exciting.. You got the panther at your breast, screaming!! Somehow you have to make this go the other way. Rather than solder flowing any old place it wants to, when it wants to. Chasing the heat, Chasi
Electronics Forum | Tue Feb 04 18:46:01 EST 2003 | slthomas
"Use the pad mating to lead wetting area." If I get your drift, we're talking about the minimum lead area (assuming the pad has an area that's at least as large as the lead) required to be wetted by IPC-610. Hmmmm...that would take some calculation
Electronics Forum | Sat Mar 08 11:04:47 EST 2003 | Joe
Mark, You've already received some good advice from the other posters. The one thing I would add is that even if you solve your printing issues on this type of part, the relative small quantity of paste may be prone to soldering problems. Ever s
