Dramatic Improvements in the Sustainability of Printed Circuit Boards

Dramatic improvements in the sustainability of printed circuit board production are now possible following the success of research supported by the Sustainable Technologies Initiative. The development could help the UK industry to reduce costs and capitalise on its exceptional design skills in today’s highly competitive global market.

‘Our results are a world first. They demonstrate that with the appropriate technology PCB manufacturing can be much more sustainable, with near-zero effluent discharges.’

‘The innovation at the core of our project is the way TAZDIS brings together individual technologies and best practices.’

Printed circuit boards – PCBs – are at the heart of virtually all today’s electronic products, from mobile phones to sophisticated computer systems. It is a huge market but one that is also highly competitive. UK manufacturers are under intense pressure to cut costs to compete in today’s global marketplace and comply with increasingly stringent environmental regulations.

A key obstacle for many producers is the poor sustainability of conventional production processes. The typical method of etching and deposition of metals such as copper, gold, nickel and tin consumes large quantities of water and chemicals, and generates large amounts of metal-bearing effluent solutions that require expensive treatment before they can be discharged into the environment. Now, in what could prove to be a major breakthrough for the UK industry, research backed by the STI programme has developed a practical way to recycle and reuse these valuable resources without making fundamental changes in production processes.

‘Our results are a world first,’ says Richard Waterhouse, Manager, Components & Manufacturing, of Intellect, the trade association for the UK hi-tech industry. ‘They demonstrate that with the appropriate technology PCB manufacturing can be made much more sustainable, with near-zero discharge on a production scale. That could make a real difference to the competitiveness of UK producers, helping them to capitalise on their exceptional design skills.’

The ‘Towards a Zero Discharge PCB Manufacturing Plant’ (TAZDIS) project was set up to develop the technology that would enable manufacturers to achieve this step change in sustainability. With backing from the Sustainable Technologies Initiative (STI), the project brought together a consortium of leading organisations, including Graphic PLC, Rohm & Haas, Printed Wiring Technologies Ltd and Giga Solutions in addition to Intellect. The STI programme, which is funded by the DTI, Defra and three research councils, aims to improve the sustainability of UK business by supporting research to achieve economic growth and employment while safeguarding the environment and conserving natural resources.

‘Conventional PCB manufacturing basically involves removing copper from PCB laminates and that is simply very inefficient from a sustainability perspective,’ explains Narinder Bains, who coordinated the TAZDIS project. ‘By integrating a number of advanced technologies we’ve made it possible to control and minimise pollution at source. Our process generates much less potentially harmful waste and minimises the amount of water needed to produce a given area of circuit board. Ultimately PCB manufacturing could be almost totally sustainable, with chemistry and water being reused and only small volumes of replenishment chemicals required.’

In the new process, special electroplating techniques make it possible to capture low levels of metals such as copper and nickel. Ion exchange systems play a key role in removing organic contaminants from rinse waters and recovering and recycling metals. Advanced oxidation methods are then used to destroy organic contaminants.

New organic and metal capture resins enhance sustainability of the ion exchange process. When the resins become saturated they can be regenerated and used again, while the liquor containing the concentrated metal ions can be recovered and recycled.

‘The destruction of organic contamination using regenerable capture resins is a particular feature of TAZDIS technology,’ says Mr Bains. ‘Conventional treatment processes rely on activated charcoal, which cannot be recycled, so this is one of the reasons our process is much more sustainable. Overall the innovation at the core of our project is the way TAZDIS brings together individual technologies and best practices from various industry sectors including the PCB and related industries for the first time.’

The clear benefits of the TAZDIS technology have been demonstrated in field trials by industrial partners. Printed Wiring Technologies Ltd (PWT) evaluated a production-scale unit in the nickel-gold stage of their normal PCB manufacturing process. Introducing the TAZDIS technology made it possible for the company to produce RoHS-compliant PCBs in-house for the first time, meeting growing demand for lead-free PCB products more competitively and swiftly. Dramatic savings in water consumption were confirmed. The ability to filter and purify water in a closed-loop system saved 500,000 litres in a month.

An added bonus of the STI research is that the technology could be applied in other industrial sectors such as metal finishing where a wide range of process chemicals is also used. Significant growth opportunities are also foreseen in areas such as the production of LCD and plasma displays, solar cells and Radio Frequency Interference Devices (RFIDs). Applications are also anticipated for each of the individual capture, treatment and recovery technologies developed, in treatment of many kinds of organic waste and landfill leachate.

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