Authored By: Dr. Samuel J. McMaster, R&D Specialist, Pillarhouse International – as seen in IPC Community Magazine: IPC Community – Community_Q325
Sustainability is more than just a buzzword for the electronics industry; it’s a key goal for all manufacturing processes. This is more than a box-ticking exercise or simply doing a small part for environmentally friendly processes. Moving toward sustainable solutions drives innovation and operational efficiency.
Reducing wastage in manufacturing can make processes more cost-efficient, thereby increasing the manufacturer’s profit. Safety also must be considered.
We all have trusted products for certain tasks, but it’s not news to anyone working in electronics that many chemicals are hazardous. As an industry, we’ve moved away from leaded solder and adapted well to alternatives. There’s no reason we can’t adapt to other elements of the manufacturing process.
This article will explore the initiatives driven by the Global Electronics Association, the inclusion of sustainability as a topic at IPC APEX EXPO (and the articles presented therein), and how selective soldering as a manufacturing process can contribute to sustainability.
A Growing Momentum
The Global Electronics Association (formerly known as IPC) recently launched Evolve, a program designed to help companies accelerate their move to sustainable processes. This platform brings together relevant articles, educational materials, industry standards, and event information. Evolve will grow with the increasing industry demand for collaboration and resources.
Momentum is growing for sustainability solutions. In a white paper, “Wired for Change: Electronics Industry Sentiment on Sustainability,” co-authored by the Global Electronics Association and the Clean Electronics Production Network (CEPN), 59% of the companies in the survey report they will increase their focus on sustainability in 2025, and 78% report being optimistic about their ability to meet their sustainability goals.
The two highest drivers for increasing sustainability are regulatory compliance and company values or culture. Other drivers, such as cost savings and efficiency, technological advancement, competitive advantage, and consumer demands, were found to be influenced mostly by customers and regulatory bodies.
On Par at IPC APEX EXPO
To pair with this initiative, IPC APEX EXPO 2025 was the first to feature a dedicated sustainability session to champion the research and development work in this area. This session will be a mainstay of future APEX EXPO conferences, featuring presentations on:
- Design considerations for sustainable PCBs
- Sustainability comparison of metallisation processes
- Recyclable and biodegradable PCB materials for reducing carbon footprint
The factors for creating more sustainable PCBs include the dimensions of the board, number of layers, via size, surface finish, and production yield, among others. Exploring the PCB manufacturing steps in more detail, as an example, the use of graphite-based direct metallization to replace the electroless copper process would eliminate a number of chemical baths and corresponding waste (rinse water, spent baths) as well as reduce air emissions. Biodegradable composites now have comparable properties to FR-4 and can be used in its place.
Material considerations, design for manufacturing, and design for reliability are, therefore, paramount. Beyond these papers at APEX EXPO, sustainability is an overall consideration for all publications and will continue for future conferences. Further reading can be found in the Technical Conference Proceedings (if you haven’t read them already).
Turning Our Attention to Manufacturing
We now have some insight into the materials assessment element of sustainability, but what can be achieved in a manufacturing process? Let’s analyse selective soldering as a manufacturing process to highlight what process optimisations can achieve.
Soldering is an energy-intensive process, whether hand soldering with high tip temperatures or selective and wave soldering utilising multi-stage pre-heating alongside multiple solder baths or large baths, respectively. The repeatability and productivity improvements of automated soldering technologies over hand soldering speak for themselves. However, how can the sustainability of these technologies be improved?
First, let’s compare wave and selective soldering. Wave soldering is an older technology and, without doubt, simpler to implement. With only a handful of variables to play with, it’s much easier to set up, but the requirements for wave pallets (masking of components) make them much more expensive than selective pallets, if they even require them. When accounting for nitrogen consumption, flux consumption, solder pot fill, dross generation, and power costs, selective soldering can be estimated to provide up to 80% cost savings when comparing the typical usage amounts of energy and materials between a wave solder platform and a selective solder platform.
At Pillarhouse, we approach each product as a process to be optimised. This essentially gives us three areas to optimise:
- Fluxing
- The pre-heating process
- Soldering itself
We aim to generate a process that achieves the highest grade of soldered joints possible. Fluxing optimisation necessitates the selection of which application method suits the product best (ultrasonic spray or the more precise Drop-jet precision droplet dispenser), pathing of the fluxer for speed of application, and the selection of flux itself. Flux selection involves balancing activity, solids content, and presence of halides, dependent upon product requirements. Post-process cleaning and the risks of electrochemical migration must be considered to extend the lifetime of the product.
When considering pre-heating, the copper content of the PCB and the thermal capacities of the components and their temperature limits must be balanced. The board and its components should reach the target temperature (to achieve flux activation and ensure proper solder wetting) within the required cycle time without damage. Using closed-loop control with a pyrometer allows for monitoring the surface temperatures of sensitive components.
Soldering itself involves programming bath positions and vectoring to quickly join components without damaging them. The choice of solder is another point for optimisation; the liquid and solid properties must be explored for proper control during deposition, wetting to the component, and final joint strength. The performance of low-temperature solders is advancing quickly, but their operating environment must be considered, and we must ask whether they meet the thermal and mechanical requirements. Lower-cost manufacturing does not justify failures in the field due to poorly chosen materials.
Conclusion
Sustainability presents rich opportunities for the electronics industry. As adaption drivers increase, there will undoubtedly be challenges, but industry collaboration will increase our toolset for adapting to changes. Manufacturing processes such as selective soldering are extremely tuneable to allow for more sustainable joining of components to PCBs.
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