Industrial Automation PCB Reliability: How to Achieve 10+ Years of Stable Operation

Therefore, I established a basic principle for the team. Problems that can be solved with a four-layer laminate structure and clever layout should never be easily upgraded to a six-layer laminate. Electrical isolation that can be achieved with routing techniques should be prioritized over adding physical layers. Non-critical defects that can be compensated for at the software level do not need to be passed on to the hardware design. Each additional layer not only means a significant increase in cost, but also may introduce new manufacturing yield risks. The end customer usually will not pay for a premium for features that exceed their actual needs.

Of course, this does not advocate going to the other extreme, that is, completely ignoring the rationality and foresight of the design. Necessary power isolation, effective shielding measures and adequate heat dissipation considerations are still indispensable core elements. The key is to find the optimal balance point between multiple constraints such as performance indicators, manufacturing cost, product reliability and development cycle, rather than blindly chasing gorgeous data on the parameter table or popular technical concepts in the industry. Essentially serving Industrial The core mission of printed circuits in the field of automation is to ensure the reliable operation of machinery and equipment rather than simply to demonstrate the technical strength of the engineering design team. Although this principle is easy to understand, it is easily obscured by various factors in daily work.

Why is substrate selection and robustness more important than simply stacking more layers?
Many people imagine that the mysteries of printed circuits used in harsh environments are too complicated. Although it is essentially different from the thin and flexible internal components in consumer electronics, its underlying logic is actually quite simple, that is, it must ensure that it can withstand the continuous pressure brought by harsh working conditions within its intended life. The longer you work in the industry, the more you can understand a profound truth. The root cause of many troublesome field failures does not stem from the insufficiency of sophisticated algorithms, but lurks in the most basic physical level. For example, the most basic substrate selection link is often ignored.

I have encountered similar situations many times. The prototype performed perfectly in the standard test environment of the laboratory. Once it was deployed to the real factory workshop and ran for several months, various sporadic failures began to occur. After in-depth investigation, it was found that the root cause of the problem was that the base material of the main control board had undergone slight deformation due to local continuous overheating, which eventually led to fatigue cracks in key solder joints. Only then did the designer deeply understand the importance of the basic characteristics of the board, such as the glass transition temperature, a parameter called the Tg value. Numbers are like the foundation of a building, which determines whether the overall structure can remain stable under high thermal loads. Imagine that various drives and controller modules are densely installed in a compact control cabinet. Heat accumulation is almost inevitable. If the copper-clad laminate used has insufficient heat resistance, as the internal temperature rises, the rigidity of the entire printed circuit will decrease, causing problems such as solder joint stress concentration. Therefore, in my design plan review, any application in Industrial For the key components of Automation PCB, I will give top priority to the long-term heat resistance and anti-aging performance of the material instead of blindly adopting the latest technical specifications or the highest nominal parameters.

As the level of functional integration increases, robust multi-level design solutions become an inevitable choice. As heterogeneous functional modules such as high-speed digital interfaces, precision analog front-ends, and high-power drive units need to be integrated simultaneously on a single printed circuit board, Multilayer is adopted. PCB has become a mainstream trend. However, the design of multi-layer stacks is far from being as straightforward as simply laminating several single boards. It involves a series of delicate challenges such as the planning of power supply ground planes, how to avoid noise sources, and electrical isolation strategies between different voltage domains. A series of delicate challenges such as electrical isolation strategies between different voltage domains need to be dealt with carefully. Based on personal experience, I think that instead of unilaterally pursuing higher stack levels or extreme minimum line widths, it is better to use engineering The design focus is placed on the robustness and manufacturability of the solution. Even a theoretically perfect eight-layer lamination design solution is no more than an armchair exercise if it exceeds the capabilities of the partner manufacturer’s existing process or results in a low production yield. Excellent design engineers should have certain back-end manufacturing knowledge and be able to predict which design decisions may cause hidden dangers in the production process to avoid risks in advance.

In the final analysis, the development of electronic products for industrial applications is essentially an art of seeking balance. Designers must find the optimal solution that is most suitable for the current project between multiple and often conflicting goals such as performance indicators, production cost, long-term reliability, and project delivery cycle. In some cases, choose a mature technology solution that has been verified in a large number of fields and match it with a reliable company that understands the characteristics of the industry. Partners are far wiser than chasing a new technology with dazzling parameters but insufficient stability verification. This is also one of the fundamental differences in design philosophy between industrial products and consumer products. The latter may focus more on novel functional experiences and ultimate cost performance, while the former requires it to be able to work consistently and stably within the next five or even ten years of service. Unsurprisingly, this is the highest compliment.