Electronics Forum | Thu Jan 27 07:18:14 EST 2000 | Christopher Lampron
Dennis, The solder paste is responsible for holding the component in place pre-reflow. Several things to look at: Is the paste accurately printed on the pad? If not, there may not be enough of the component in contact with the paste to provide adiq
Electronics Forum | Tue Jan 31 15:51:04 EST 2006 | russ
Relays huh? I can tell you from previous experience that relays are not a good heat gun candidate. Did you check how long this part can withstand the 240? I do not know what the 4 setting is on a liester but it is probably well in excess of the 24
Electronics Forum | Sat Mar 11 11:10:05 EST 2006 | eolparts
Hello All, I sent Grant an e-mail and I wanted to share with you. My name is Jim Schreiber and I am the product mgr at EOL Parts Inc. We have access to over 1000+ OEM and CEM excess/surplus inventories that we use on a regular basis to pass on cost
Electronics Forum | Mon Nov 06 10:29:28 EST 2000 | Dean Stadem
All of the replies have merit. Here is another one. Because the cause of the tombstoning is wetting forces that are imbalanced, and one end wets faster or more readily than the other, the 0402 lifts up on that end easily because of its low mass. Incr
Electronics Forum | Mon Nov 25 09:34:52 EST 2002 | davef
You're correct excessive temperature can cause dewetting, but that usually means realeeee hot. Excessive time at above liquidous will cause dewetting also.
Electronics Forum | Wed Aug 27 14:38:20 EDT 2008 | rgduval
Does your paste provider recommend a TAL? For the leaded and lead-free pastes that we use, the manufacturer recommends 60 seconds above liquidous. I note that your profile shows the TAL as 30 seconds, which may not be sufficient. That said, tho
Electronics Forum | Fri May 01 08:15:36 EDT 2009 | davef
Scavenging Methods [Improve Solder Scavenging of Large Area-array Sites, SMT, Laurence Harvilchuck, process research engineer, Unovis Solutions, harvilch@unovis-solutions.com] Two common methods exist for scavenging residual solder on the site for s
Electronics Forum | Fri Dec 17 16:23:22 EST 1999 | Mike Naddra
Hello Henry, Tombstoning is caused (In most cases) by a force imbalance on either side of the component. As the solder becomes liquidous the surface tension of the liquid will pull the component to the center of the liquidous area. To solve the probl
Electronics Forum | Tue Jul 30 10:44:20 EDT 2019 | vchauhan
Can anyone please share a document which details about the soldering defects if you have less or the excessive preheat time, soak time, peak temperature, time above liquidous (TAL)and cooling time. Appreciate your help in advance.
Electronics Forum | Wed Oct 09 20:52:27 EDT 2002 | davef
Russ, Be careful on how you determine your liquidous point. Sure 205-210�C is fine if your paste and the solderability protection on pads and component leads are near eutectic solder and things worked according to plan, but in real life it doesn't
