Technical Library | 2019-05-24 09:22:59.0
There is a smaller process window and a much narrower margin of error when creating and using lead-free reflow profiles for surface mount parts on printed circuit boards (PCBs). Solder balls, dewetting, tombstones, voids, and head-on-pillow problems will occur much more frequently because lead-free alloys behave differently than eutectic pastes. Problems are compounded due to the extra heat necessary for some lead-free pastes to reach their melting points.
Technical Library | 2013-07-18 12:12:40.0
Lead-free nanosolders have shown promise in nanowire and nanoelectronics assembly. Among various important parameters, melting is the most fundamental property affecting the assembly process. Here we report that the melting behavior of tin and tin/silver nanowires and nanorods can be significantly affected by the surface oxide of nanosolders.
Department of Chemical Engineering, University of Massachusetts
Technical Library | 2014-11-28 15:55:13.0
A soldering alloy composition Sn40-Bi60 has been manufactured by quenching method to achieve the both cast and wire shape. Differential scanning calorimetric (DSC) was done to study the melting behavior for a large portion of the alloy melts sharply at a approximately 136 C0 ,the melting point of Sn-Bi. X-Ray diffraction and optical microscopy were used to analyzed its microstructure characterization. The hardness of the alloys has been tested and find at a value 2 HRB as ductile form.
Technical Library | 2007-11-01 17:16:07.0
This paper discusses micro-filled epoxy-based conducting adhesives modified with nanoparticles, conducting polymers, and low melting point (LMP) fillers for z-axis interconnections, especially as they relate to package level fabrication, integration,
Technical Library | 2008-01-03 17:50:51.0
Lead-free SMT can be achieved reliably if several process requirements are implemented carefully. Some of the variables to account for are listed below. The most common alloys used in lead-free SMT are tin-silver-copper alloys; these alloys all have a meting range between 217- 220°C. These alloys all melt at higher temperatures than traditional leaded solders such as the 63/37which has a melting point of 183 °C.
Technical Library | 2013-01-05 22:21:01.0
More and more countries legislate to forbib lead usage in solder material. However, the lead-free solder wire has higher melting point and soldering temperature, increase soldering iron temperature may damage the PCB or components. How to solve this problem?
Technical Library | 2023-02-13 19:04:25.0
The tin whisker phenomenon is a failure mode associated with all electronic devices that use a number of low melting point elements (e.g., Sn, Cd, In) in operations such as soldering. Recognized many years ago, the problem was minimized by adding lead, now identified as a hazardous substance and banned
Technical Library | 2019-05-29 01:47:22.0
1.Vias near SMD pads: Solder can flow into the via after melted. As a result cold joint will appear in the end. Check the picture below. 2.Vias on SMD pads: Solder can flow into the via more easier after melted. Check the picture below. 3.Via opening without soldermask covered. When workers solder TH parts by hand, soldering iron can touch vias sometime, then tiny amounts molten solder will stay on vias. This can lead to electrical short easily. We recommend you make all vias tenting (covered by solder mask) if it is possible.
PCBNPI-Professional PCB Fab/PCB Assembly Service Provider From China
Technical Library | 2021-08-25 16:34:37.0
As the traditional eutectic SnPb solder alloy has been outlawed, the electronic industry has almost completely transitioned to the lead-free solder alloys. The conventional SAC305 solder alloy used in lead-free electronic assembly has a high melting and processing temperature with a typical peak reflow temperature of 245ºC which is almost 30ºC higher than traditional eutectic SnPb reflow profile. Some of the drawbacks of this high melting and processing temperatures are yield loss due to component warpage which has an impact on solder joint formation like bridging, open defects, head on pillow.
Technical Library | 2017-10-05 17:13:04.0
Intermetallic compounds (IMC) in solder bonds are commonly considered critical for the reliability of interconnections. The microstructure and thermal aging characteristics of solder bonds of crystalline silicon solar cells are investigated, whereby two solders, Sn60Pb40 and a lead-free, low melting point alternative Sn41Bi57Ag2 are considered.
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