Electronics Forum | Fri Jun 16 10:38:33 EDT 2000 | Iain
I have 15 very large backplanes (.156" thick Au plating) that the ground pins of a high density thru-hole connector were not thermal relieved in the artwork. As a result we are unable to solder the 8 pins that connect to the ground plane. We know t
Electronics Forum | Fri Jun 16 11:08:30 EDT 2000 | Travis Slaughter
Did you try preheating the board then hand solder? Those little heat shrink guns work great for this.
Industry News | 2003-03-11 08:45:00.0
CAMtastic DXP is the latest version of Altium's complete CAM verification and editing system that bridges the gap between PCB design and manufacturing and facilitates communication between board designers, fabrication engineers, and their clients.
Industry News | 2018-10-18 08:29:16.0
How to Prevent Short Circuits to Ground in QFN Components?
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.
Technical Library | 2020-10-14 14:33:36.0
Epoxy based adhesives are prevalent interface materials for all levels of electronic packaging. One reason for their widespread success is their ability to accept fillers. Fillers allow the adhesive formulator to tailor the electrical and thermal properties of a given epoxy. Silver flake allow the adhesive to be both electrically conductive and thermally conductive. For potting applications, heat sinking, and general encapsulation where high electrical isolation is required, aluminum oxide has been the filler of choice. Today, advanced Boron Nitride filled epoxies challenge alternative thermal interface materials like silicones, greases, tapes, or pads. The paper discusses key attributes for designing and formulating advanced thermally conductive epoxies. Comparisons to other common fillers used in packaging are made. The filler size, shape and distribution, as well as concentration in the resin, will determine the adhesive viscosity and rheology. Correlation's between Thermal Resistance calculations and adhesive viscosity are made. Examples are shown that determination of thermal conductivity values in "bulk" form, do not translate into actual package thermal resistance. Four commercially available thermally conductive adhesives were obtained for the study. Adhesives were screened by shear strength measurements, Thermal Cycling ( -55 °C to 125 °C ) Resistance, and damp heat ( 85 °C / 85 %RH ) resistance. The results indicate that low modulus Boron Nitride filled epoxies are superior in formulation and design. Careful selection of stress relief agents, filler morphology, and concentration levels are critical choices the skilled formulator must make. The advantages and limitations of each are discussed and demonstrated.
SMTnet Express, May 7, 2020, Subscribers: 36,108, Companies: 11,001, Users: 25,793 Solutions for Selective Soldering of High Thermal Mass and Fine-Pitch Components Credits: Nordson SELECT The selective soldering process has evolved to become a
ASYMTEK Products | Nordson Electronics Solutions | https://www.nordson.com/en/divisions/efd/products/thermal-compounds?con=t&page=24
Thermal Interface Materials (TIM) | Thermal Compound | Nordson EFD Nordson EFD Corporate | Global Directory | Languages Division Only All of Nordson Home Products Accessories
| https://www.eptac.com/faqs/ask-helena-leo/ask/j-std-001e-2010-4-5-1-gold-removal-issues
: This is a new application for components where there is a bottom pad for either thermal relief or electrical functionality. The ability to tin these pads with the proper solder alloy could impact the coplanarity of the device when it is assembled to the printed board
