Institute of Circuit Technology Spring Seminar 2020

Estimated reading time: 11 minutes

Daniel Ray described a process for gold bioleaching using thiourea—a less harmful alternative to biogenic cyanide, and indium bioleaching from display screens using an acidolysis bioleaching mechanism. Future work planned included reuse of materials, precious metal recovery, genetic modification of bacteria, and large-scale application of the technology.

Newly appointed Chair of the ICT, Emma Hudson provided delegates with a comprehensive first-hand update on current IEC and UL standardisation work. The scope of IEC TC 91—the technical committee for electronics assembly technology—was to establish international acceptance for standards and guidelines in electronics assembly technology.

Hudson is convenor of the IEC TC 91 working group responsible for preparing international standards on design, manufacturing, and testing of electronic assemblies—including the requirements and tests for materials and components used to manufacture circuit boards and electronic assemblies, as well as the formats of electronic data and libraries for describing these products and processes. She showed a long list of recent publications, with items of interest highlighted. There were 29 documents currently being worked on—24 new and five being revised, of which 20 were standards, and three were technical reports.

Hudson is EIPC’s representative on the UL Standards Technical Panel for the UL 796, UL 796F, UL746E, and UL 746F standards. Probably the most relevant upcoming proposal from UL was to rename “solder limits” as “assembly soldering process” to provide a clearer interpretation of the significance of the parameter in representing the soldering processes the PCB would be exposed to during component assembly operations. New limits followed research from FED and ZVEI, and the proposed default condition would be six cycles of IPC-TM-2.6.27 T260 reflow, or a special reflow profile if agreed with the OEM or ODM.

The reflow profile would be considered representative of wave and selective soldering, and UL’s follow-up service inspectors would check the maximum reflow temperature and the number of soldering cycles that the assembly was exposed to, but would not be checking details of the reflow profile beyond this. There was no plan to retrospectively apply the new assembly soldering process limits to existing board types—only to new evaluations, once the proposal had been accepted and added to UL 796, UL 746E, UL 796F, and UL 746F. And there was no guarantee that the proposal would be accepted by the UL Standards Technical Panel, although it was expected to happen with the coming 6–18 months.

A significant new proposal presented at the UL Standards Technical Panel meeting came from Alun Morgan, representing Ventec. He suggested that the STP consider defining laminate groups by performance instead of nominal chemistry, to align with the industry and help designers in specifying their PCB requirements.

Dr. Jonathan Swanston, chief technical officer with Jiva Materials, gave an update on the ReCollect project, funded by Innovate U.K., and focused on the efficient manufacturing of recyclable composite laminates for electrical goods. Jiva Materials was one of three project partners—the others being Coventive Composites, an independent provider of expert services relating to composite materials, and the ICT, supporting dissemination and industry feedback. Jiva had developed the world's first fully recyclable PCB laminate. He passed around samples of his material, composed of a natural fibre bound with a polymer soluble in hot water but not in cold water, which had the appearance of a light-brown-coloured unclad laminate.

Dr. Swanston reviewed some statistics which indicated that PCBs made up 8% of the 50 million tonnes of electronic waste that was generated in 2018. The ReCollect project explored an alternative way of managing end-of-life circuit boards. Currently, the only practical way of recycling glass-epoxy circuit boards involved shredding and incineration to recover the metal content. The ultimate aim of the project was to remove glass-epoxy boards from the supply chain, by demonstrating that Jiva’s Soluboard® could match the performance of CEM-1 and FR-4 materials.

Dr. Swanston explained that Soluboard was a fully biodegradable and non-toxic product based on flax. A primary aim of the project was to demonstrate the feasibility of producing the material in high volumes at a competitive price, using a continuous-production process in development by Coventive Composites.

The nature of Soluboard® was to delaminate when immersed into hot water, enabling the flax fibres to be composted or repurposed and the electronic components to be removed for reprocessing. Silver printing was a feasible method for creating functional circuits. But to use existing aqueous manufacturing processes, it was necessary to seek a means of chemically protecting the material in-process, and this was part of the project.

Dr. Swanston commented that “white goods”—large household appliances—constituted more than 30% of e-waste, and that the Global E-Waste Monitor had reported that less than 20% of this was documented as collected and recycled. The rest went to landfill. Jiva intended to push for the safe recovery of e-waste in line with the WEEE2 Directive.

The white goods market was their initial target, and specifications from potential customers had defined electrical, flammability, and mechanical requirements. Soluboard® had a Tg of 126°C and a UL94V0 flammability rating. Its electrical properties were being determined by a third-party laboratory, and final results were awaited. As part of the project, functioning populated PCBs would be designed, manufactured, and evaluated as specified by end customers.

Government policy clearly aims to end the sale of new diesel and petrol cars by the year 2035 and compel the mass adoption of electric vehicles. The cost of the battery currently represents a significant proportion of the overall cost of an electric vehicle; the battery gradually loses its capacity and is typically replaced when it drops to below 70–80% of the original. The first generation of vehicle batteries are reaching end-of-life now, and volumes are set to increase significantly.

To reuse in secondary applications or to recycle to recover raw materials were questions explored in an informative presentation from Professor Martin Goosey. In the context of a circular economy, it made sense to reuse and then recycle, but both possibilities had some merits.

The number of end-of-life vehicle batteries was predicted to grow from 55,000 in 2018 to 3.4 million by 2025 and 6.0 million by 2030, and this represented around 275 gigawatt-hours of capacity. Should electric vehicle batteries be used for home energy storage, and was this an economic proposition for the average user? Tesla, for example, manufactured rechargeable lithium-ion batteries for stationary energy storage but preferred to recycle its used batteries. Although there were several nominal benefits of reusing vehicle batteries, the negatives included transport costs and the costs of dismantling, testing, reassembly, and certification. There were many different types of battery chemistry and size, and although reuse would nominally extend the life, the batteries would ultimately need recycling anyway.

The need to balance power availability was becoming more important with the growth of electricity generation from intermittent sources; for instance, the solar industry heavily depended on the cost-effective integration of appropriate energy storage systems. Battery performance was continuously improving, and new battery costs were reducing. The example quoted by Professor Goosey indicated that the cost per kilowatt-hour in 2020 was 20% of the 2010 figure, projected to fall to 10% by 2030. Why not just use new batteries and simply recycle the old ones? The best route was still to be determined. However, with the move to electric vehicles being accelerated by government policy, it would be vitally important that the correct decisions were taken.

Professor Goosey wrapped-up the proceedings, thanking all of the participants. He also gave a special thanks to Bill Wilkie for his superb organisation and management of the event.

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