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60 SMT007 MAGAZINE I SEPTEMBER 2025 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," authored by the Global Electronics Association, 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 increas- ing sustainability are regulatory com- pliance and company values or culture. Other drivers, such as cost sav- ings and efficiency, technolog- ical 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 develop- ment work in this area. This session will be a main- stay 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 num- ber 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 assess- ment 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 solder- ing 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 comp- onents) make them much more expensive than selective pallets, if they even require them. When accounting for nitrogen consumption, flux consump- tion, 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 preheating process • Soldering itself We aim to generate a process that achieves the highest grade of soldered joints possible. Flux- D r. S amuel McMaster