Electronics Forum | Thu Nov 18 10:56:16 EST 1999 | Dave F
Jacky: There�re major four factors that affect the reliability of a solder connection. 1 Design of the connection including the shape and height of the lead and the type and amount of solder. 2 Dissolution of base metals into the solder connection.
Electronics Forum | Thu Jan 13 09:18:28 EST 2005 | davef
We agree that coating BGA solder balls with conformal coat is a bad idea due to differences between the z-dimension thermal expansion between the conformal coat and solder.
Electronics Forum | Fri May 31 10:15:30 EDT 2019 | davef
Major sources of crack in the solder connection after thermal cycling are: * Thermal heating caused by differences in thermal expansion between the board and the component * Lead-free solder is more rigid and brittle than eutectic solder in simila
Electronics Forum | Fri Sep 15 16:37:49 EDT 2000 | Dave F
Sounds like someone aimin� fo tha big hurt, if ya axes me. Two spots to place your lawn darts are: 1 J Hwang in "Modern Solder Technology � " states (p.354) that " � extreme CTE mismatch between silicon IC (~2) and the PCB (~16), solder connections
Electronics Forum | Wed Jan 12 10:15:43 EST 2005 | davef
We conformal coat our boards and get pretty good coverage along the edges of BGA. If you need coverage along the edges and are not getting it, your supplier may be able to recommend a different material or application method. Most often, underfill
Electronics Forum | Tue Dec 28 03:59:06 EST 2010 | riscy00
I'm investigating heat transfer by 1st order approximation between PCB and ambient air via encapsulate material (epoxy or gel or silicone), they have thermal conductivity of 0.2W/C but it hard to find specific heat capacity and density. Has anyone
Electronics Forum | Mon Nov 12 16:13:48 EST 2001 | davef
Underfill is primarily used in flip chip, CSP attach applications. It is used to balance the differing thermal expansion rates for an organic board, solder, and silicon die. There are a fair number of papers written on this in the SMTA [www.smta.or
Electronics Forum | Wed May 22 05:10:45 EDT 2002 | johnw
Ron, The new ystem is probably the best one I've seen for useability, the who thing can be driven by wizards to guide people through what they need to do. The system has the ability to set alarm's that will basically analyse your result's for you an
Electronics Forum | Mon Mar 12 09:25:16 EDT 2007 | rgraves
Our internal designers are employing SMT connectors that utilize a �PCB positioning boss� in conjunction with normal gull wing leads. The use of these devices is based on the advertised ability of the boss to prevent �mis-insertions� and assist in �
Electronics Forum | Tue Jul 09 22:12:03 EDT 2019 | eddy2019
The price increase of electronic components such as MLCC has not stopped. In recent years, driven by the development of electric vehicles, industrial control and other industries, the demand for MLCC products has increased rapidly. However, the overa
