Adaptability in all aspects is the PCB industry's greatest strength.

“Change is inevitable – except from a vending machine.” – Robert C. Gallagher

It’s an amusing quip (although perhaps increasingly incongruous given the rapid adoption of contactless payments) that lets me comment on some of the transformations we have experienced in the PCB industry over recent years. Some challenges, such as thermal management, had receded for a time but are now back and more urgent than ever. Others, like the constant demand to support faster and faster signal speeds, demand that we continue to extend the limits of performance from the materials and techniques at our disposal.

The PCB’s role has become hugely more significant and influential as electronic systems have gotten more complex, more performance hungry, and more mission critical. It has extended from providing basic mechanical support and connectivity to becoming a comprehensively engineered part of the system.

The electronics industry of today is vastly different from the way things were as recently as the 1980s. Thermal management was a great challenge, largely due to the inefficiency of circuits such as linear power converters and power amplifiers. The adoption of much more efficient switched techniques, as well as exponentially smaller chip fabrication processes, solved that challenge for a while.

Data for the sake of data can do more harm than good.

Data can be very useful, in moderation! Over what seems like a very long career I have seen data used and have used data for a great number of purposes. But “data,” of course, can mean different things.

Early in my career during the 1970s, data were what I would consider “flat” numbers. If a machine had a counter, if you could measure or quantify a dimension via some type of gauge, that was considered best-in-class “data.” During the 1980s, computers became more powerful and programmers were more adept at identifying information that previously could not be easily obtained. The power of large computing combined with the evolving skills of computer programmers ushered in new, never doable concepts such as logistics to be able to smartly schedule the entire manufacturing process from procurement to shipping.

Late in the 1980s, personal computers had evolved, and user-friendly software programs such as Lotus 1-2-3, Excel, Word, etc., enabled an expanded group of employees to collect information and create far more usable “data.” These users of PCs were often not professional programmers, but the actual shop floor operator or supervisor who needed the data output but also understood the source of all the inputs. In many ways, the late 1980s through 1990s was a period of quantum expansion of data use. Both the user and generator of information could write programs where the information could be input and sliced and diced through pivot tables to generate far more usable “data.” Of course, this worked only as well as the quality of both the inputs and formulas utilized.

As material supplies loosen, the winners and losers will change.

The biggest trend I’ve seen in the electronics manufacturing services (EMS) industry this year is that OEM customers are starting to move. Materials availability has improved enough that OEMs are starting to move from EMS companies or regions they consider problematic, plus source new projects. The dynamics of this type of market are different from a normal EMS account acquisition cycle for two reasons. First, the past three years represented the worst material constraints that this market has ever experienced. Second, the labor shortages driven by Covid have created service issues on top of the material availability issues.

If past is prologue (and in the EMS industry it usually is), OEMs will change their sourcing behavior. They will be more secretive about intent to change suppliers and they will make decisions faster. EMS companies that adapt to this situation will have a banner year in acquiring new customers. EMS companies that have been underperforming or fail to speed up their responsiveness on inquiries and quotes will lose existing business and opportunities for new business.

“Bargain” materials can result in subpar outputs.

We’ve covered understencil cleaning topics in this column many times. Admittedly, if the stencil printing process were perfect, understencil cleaning wouldn’t be required. But it is not an ideal world; we have board stretch, interspace challenges, and the compromise of printing speeds versus pressures to achieve balanced aperture filling.

Here is the basis for some of these challenges: If all the apertures were identical, the filling process (print speed/print pressure) could be optimized around one architecture. But, with the reality of different aperture shapes and sizes, the filling process must have a middle ground. The larger apertures fill more efficiently; thus, the filling process can deliver slightly too much fill on certain apertures, causing excessive material which may lead to solder paste bridging.

Conversely, the smaller apertures have a lower filling efficiency and, under the same speed and pressure setting, can be starved of solder paste, causing an insufficient fill. Insufficient deposited material can also result from an aperture with a low/tight associated area ratio. A low area ratio aperture has a lower transfer efficiency, which means that some of the material may remain in the aperture after filling. Eventually, this unreleased material can block the aperture, requiring understencil cleaning.