Our expert troubleshoots three common problems.

Regular readers of this column and certainly most process engineers are acutely aware of the multitude of problems that can arise in the stencil printing process if it is not optimized. With numerous inputs and variables – shown in the fishbone diagram (FIGURE 1) – the number of things that can go wrong are many, but that shouldn’t portend that things will go wrong. Stencil printing, as I’ve said before, can be simplified into having the right amount of material at the right time in the right place. Therefore, too little or too much material, or improper timing or location, can result in defects. On the flip side, knowing how to avoid or correct the most common printing defects can mitigate against proliferation and secure successful results. This month, we look at the basics, discuss the top three printing-related defects and the problems they cause, and share advice on how to resolve them. (Caveat: There are multiple potential causes and cures; here, we discuss the most common.)

Problem: Insufficients (too little material).
Potential result: A dry joint or a faulty/unreliability interconnect in the field can cause a broken circuit, often brought on by temperature or vibration stress.
How to avoid or correct:

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Should the toe be exposed?

This month we look at solder toe fillets. A solder toe fillet is part of the solder joint visible on most gullwing terminations. These are typically seen on SOIC, QFP and surface mount connectors. FIGURE 1 shows satisfactory joints with no or limited toe fillets.

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Are low-loss flex circuit materials an enabler?

Saab may have been first to bring aerospace technologies overtly into the automotive world when it introduced the aerodynamically styled 92 in 1948. The idea proved popular and effective, setting a trend that has made technologies such as infrared vision, radar and heads-up displays common features in today’s vehicles.

The flow of technology and know-how may soon be seen in reverse, as the aviation industry seeks to clean up its environmental credentials. In my last column, I mentioned Airbus’ recent flying achievements with fully electric planes. The company is also experimenting with hybrid platforms powered by a combination of lithium-ion batteries and a range-extending combustion engine, and recently unveiled several new hydrogen-powered concepts.

We can expect technological progress toward larger planes capable of longer flights; the ultimate goal, obviously, is zero-emission planes operating commercially viable services. Key challenges facing battery-powered electric aircraft include compensating for the extra weight of large Li-ion batteries. There are also demands for charging infrastructure and safe solutions to minimize recharging times so operators can turn services around quickly. The automotive industry has experience dealing with these issues and could provide solutions.

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Traditional materials such as whitepapers and articles are solid lead generators.

What a difference a year makes. As I write this, three Covid-19 vaccines are approved and are in distribution to healthcare workers and nursing homes. By the time this is printed, it’s likely the next tier of eligible recipients will be able to get a shot at a pharmacy or their doctor. The speed of development, manufacturing, testing and deployment is unparalleled. The teams involved in this have set the stage for a return to normalcy. Yet it is likely Covid-19 will have a global impact on business travel and selling processes for most of 2021, because it will take time for herd immunity to develop. So, what should sales and marketing teams in the electronics manufacturing services (EMS) industry expect as we transition back to normal?

The need for speed. OEMs discovered some EMS companies could cut new product introduction (NPI) time significantly during 2020. The bar will likely stay raised, both because it provides competitive advantage and because unanticipated variations in demand require it. Companies able to exploit their success in this area will likely see additional new business.

Demand will be more variable than usual. While parts of the economy have been almost normal for months, some regions experienced shutdowns. There is also pent-up demand for products such as appliances that experienced shortages in 2020. Consumer lifestyles changed in 2020 and are likely to impact buying patterns in 2021. A telecommunications technology shift is in play with 5G, and potentially political incentives for alternative energy products. From a sales perspective that translates to new opportunities in markets that may not have been as attractive in prior years.

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