Should chemistry formulation and drying time factor into solvent selection?

The practice of periodically wiping excess solder paste off the side of the stencil that contacts the PCB during the printing process can take many different forms and frequencies. The objective of wiping is to remove unwanted solder paste from the contact side of the stencil.

How does solder paste find its way to the contact side of the stencil? By nature, solder paste sticks to both the PCB pad and the stencil. It does not fully release from the aperture upon separation, depending on the area ratio (AR) of the aperture. Very often, transfer efficiency (TE), or the amount of solder paste removed from the aperture, is less than 100%. The remaining paste often forms “strings” that snap back to the stencil’s contact side (Figure 1).

A closer look at mixing methods and automated mixers.

While automation in manufacturing brings efficiency and consistency, the use of automated solder paste mixers is a topic of debate, with significant concerns over their impact on the paste’s properties. This comprehensive analysis delves into why many industry experts advise caution.

Solder paste is not just a blend of materials; it’s a finely tuned compound where each element plays a specific role. The balance between solder powder and flux is crucial, as it determines the paste’s behavior during the printing process and affects the quality and reliability of solder joints. Certain properties of the paste – its viscosity, rheology and thixotropy – fundamentally determine how well it will perform and can be significantly affected by how the paste is handled.

A special panel discusses the growth of AI tools and its possible effects on the industry.

“Will AI take my job?”

That’s the question on the mind of many around the world today – including electronics engineers and PCB design engineers – and was one of several questions considered during an online panel hosted by PCEA in March.

A group of panelists with notable AI experience – Circuit Mind’s Tomide Adesanmi, Cadence Design Systems’ Taylor Hogan, Zuken’s Kyle Miller, Luminovo’s Sebastian Schaal and Siemens Digital Industries’ David Wiens – gathered to share predictions for the future of AI in the electronics supply chain and answer questions from an audience of industry professionals.

A showcase of testing methods used in the development of robust materials.

Ruggedization means “to strengthen (something, such as a machine) for better resistance to wear, stress, and abuse.”¹ Automotive systems are built for aggressive environments and are categorized as ruggedized electronics. One usually thinks of an all-terrain vehicle navigating an uneven landscape in an extreme hot or extreme cold environment. The systems require more robust electronic hardware due to their unusual working conditions and environmental exposure.

Today’s automotive electronics, specifically those for advanced safety features, require ruggedization against traditional as well as additional self-inflicted abuse. The high level of processing required to execute “sense” and “respond” of multiple safety systems working in concert creates increased heat and increased mechanical strain leading to shorter characteristic life. Advanced IC substrate packages create challenges for the system as well. The need to combat these additional challenges requires specific ruggedization. This work will discuss material choices that were designed to combat temperature, vibration, heat, and various aggressive environments to offer extended system life.