Technical Library | 2007-04-18 19:23:22.0
Recent investigations have revealed that Pb-free solder joints may be fragile, prone to premature interfacial failure particularly under shock loading, as initially formed or tend to become so under moderate thermal aging. Depending on the solder pad surface finish, different mechanisms are clearly involved, but none of the commonly used surface finishes appear to be consistently immune to embrittlement processes. This is of obvious concern for products facing relatively high operating temperatures for protracted times and/or mechanical shock or strong vibrations in service.
Technical Library | 2013-01-17 15:34:33.0
The use of an electroless nickel, immersion gold (ENIG) surface finish comes with the inherent potential risk of Black Pad failures that can cause fracture embrittlement at the interface between the solder and the metal pad. As yet, there is no conclusive agreed solution to effectively eliminate Black Pad failures. The case studies presented are intended to add to the understanding of the Black Pad failure mechanism and to identify both the plating and the subsequent assembly processes and conditions that can help to prevent the likelihood of Black Pad occurring.
Technical Library | 2014-08-07 15:13:44.0
Gold embrittlement in SnPb solder is a well-known failure mechanism in electronic assembly. To avoid this issue, prior studies have indicated a maximum gold content of three weight percent. This study attempts to provide similar guidance for Pb-free (SAC305) solder. Standard surface mount devices were assembled with SnPb and SAC305 solder onto printed boards with various thicknesses of gold plating. The gold plating included electroless nickel immersion gold (ENIG) and electrolytic gold of 15, 25, 35, and 50 microinches over nickel. These gold thicknesses resulted in weight percentages between 0.4 to 7.0 weight percent.
Technical Library | 2019-10-29 02:55:33.0
For every 10 ℃ increase in temperature, the reaction rate is twice to three times. This means that for every 10 ℃ increase in temperature, the life span of the product will be halved, and when the temperature rises by 20 ℃, the life span of the product will be reduced to 1/4. High temperature will lead to aging, oxidation, evaporation, physical deformation and so on. Low temperature will lead to embrittlement, ice formation, viscosity and solidification degree, loss of mechanical strength, physical shrinkage and so on. When the product is shipped, stored and operated in the environment, it will be endangered. In addition, each product has regulatory and certification requirements, and it is important to evaluate reliability and durability before it is put on the market. In general, according to the IEC60068 test standard, it requires the volume of the laboratory to be at least five times the total volume of the sample under test. Haida constant temperature and humidity box can help you meet this demand. So with the fast developmement of manufacturing industry,test becomes a necessity to see wether the product is able to meet regulated standards in R&D satge,Climatest Symor specializes in handling temperature and humidity,we supply environmental test chamber to China State-owned Research Institutes and laboratories,and obtain excellent reputation from international cllients,our company put much efforts on chamber R&D ,striving to supply best-quality climate simulation equipment and after-sale service. For details,pls visit our official website www.climatechambers.com
Technical Library | 2022-08-08 15:06:06.0
Selective soldering has evolved to become a standard production process within the electronics assembly industry, and now accommodates a wide variety of through-hole component formats in numerous applications. Most through-hole components can be easily soldered with the selective soldering process without difficulty however some types of challenging components require additional attention to ensure that optimum quality is maintained. Several high thermal mass components can place demands on the selective soldering process, while the use of specialized solder fixtures, or solder pallets, often places additional thermal demand on the preheating process. Fine-pitch through-hole components and connectors place a different set of demands on the selective soldering process and typically require special attention to lead projection and traverse speed to minimize bridging between adjacent pins. Dual in-line memory module (DIMM) connectors, compact peripheral component interface (cPCI) connectors, coax connectors and other high thermal mass components as well as fine-pitch microconnectors, can present challenges when soldered into backplanes or multilayer printed circuit board assemblies. Adding to this challenge, compact peripheral component interface connectors can present additional solderability issues because of their beryllium copper base metal pins. Key Terms: Selective soldering, drop-jet fluxing, sustained preheating, flux migration, adjacent clearance, lead-to-hole aspect ratio, lead projection, thermal reliefs, gold embrittlement, solderability testing.
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