Technical Library | 2002-03-07 17:00:40.0
Electrovert problems & solutions reflow & wave soldering.
Technical Library | 2006-12-18 14:55:35.0
Many solder users have preconceived notions and worries involving reflow profiling guidelines. Year after year of reading profiling recommendations in industry publications, from a litany of pundits, has made it clear that perfect profiles exist and should be sought after. They feel if the solder supplier gives them a tidy drawing on a piece of paper with times and temperatures that it will magically solve all their reflow problems. This is, unfortunately, an often incorrect assumption.
Technical Library | 2022-12-23 20:44:54.0
One of the upcoming reliability issues which is related to the lead-free solder introduction, are the headin-pillow solderability problems, mainly for BGA packages. These problems are due to excessive package warpage at reflow temperature. Both convex and concave warpage at reflow temperature can lead to the head-in-pillow problem where the solder paste and solder ball are in mechanical contact but not forming one uniform joint. With the thermo-Moiré profile measurements, this paper explains for two flex BGA packages the head-in-pillow. Both local and global height differences higher than 100 µm have been measured at solder reflow temperature. This can be sufficient to have no contact between the molten solder ball and solder paste. Finally, the impact of package drying is measured
Technical Library | 2023-09-23 22:29:02.0
Moisture trapped within components and PBs presents a serious problem during the fabrication and assembly process. Too much moisture can lead to board failures when it is turned to steam during the reflow process.
Technical Library | 2009-03-13 00:27:09.0
Open product reliability testing in Stockholm, Sweden in January as part of a live production event generated some quite startling results. It was apparent that many components simply cannot handle the high reflow temperatures of a lead-free soldering process, and that many surface-mount machine suppliers are battling significant problems with QFN packages and other components that are mounting edgeways (bill boarding). However, some suppliers have achieved good results.
Technical Library | 2020-11-04 17:57:41.0
Residues present on circuit boards can cause leakage currents if not controlled and monitored. How "Clean is Clean" is neither easy nor cheap to determine. Most OEMs use analytical methods to assess the risk of harmful residues. The levels that can be associated with clean or dirty are typically determined based on the exposed environment where the part will be deployed. What is acceptably clean for one segment of the industry may be unacceptable for more demanding segments. As circuit assemblies increase in density, understanding cleanliness data becomes more challenging. The risk of premature failure or improper function is typically site specific. The problem is that most do not know how to measure or define cleanliness nor can they recognize process problems related to residues. A new site specific method has been designed to run performance qualifications on boards built with specific soldering materials, reflow settings and cleaning methods. High impedance measurements are performed on break off coupons designed with components geometries used to build the assembly. The test method provides a gauge of potential contamination sources coming from the assembly process that can contribute to electrochemical migration.
| 1 |
.gif)
