ICT Evening Seminar - Addressing Environmental Needs
Darlington UK. 3rd September 2008
Darlington, in the north-east of England, famous for its association with the world's first passenger rail journey in 1825, was the venue for a well-attended Institute of Circuit Technology evening seminar on the theme “Addressing Environmental Needs”. The seminar focused upon the impact and mitigation of environmental legislation on printed circuit fabricators and their suppliers. Delegates travelled from all over the UK to attend, accompanied by a deluge of rain that had made its way from somewhere in mid-Atlantic.
Introduced by ICT Technical Director Bill Wilkie, Tom Brown of Holders Marketing, a Fellow of the Institute, began the evening’s proceedings with a paper discussing methods of assessing the potential reliability of laminates during lead-free soldering processes. He explained that simply specifying materials according to IPC 4101 slash sheets might not be sufficient to ensure a particular thermal performance in critical applications. Acknowledging work published by Werner Engelmair, Tom explained the derivation of the Soldering Temperature Impact Index, a function of readily available data: glass transition temperature, decomposition temperature and Z-axis thermal expansion coefficient: STII = Tg/2 + Td/2 — (TE%(50 to 260°C) x 10), which gave a meaningful indicator of the thermal stability of a laminate during soldering. An STII-value of 215 or greater was recommended for PCBs of 1.5mm or more in thickness.
Specialist in cleaning processes for electronics assemblies, Graham Fraser of Fraser Technologies gave an insight into the types of equipment and chemistries currently available, and reviewed both solvent and aqueous systems. He explained that there was no single ideal system, and many factors needed to be taken into account such as current and local legislation directives, level of cleanliness required, volume of circuits to be processed, component and bare board compatibility, as well as available space with respect to equipment footprint. Cost was clearly an important issue. At the lower-cost end of the scale were small batch-type processes in both solvent and aqueous chemistries. Then came the sealed solvent and larger in-line aqueous systems capable of high volume throughput, all of which had to meet and exceed current environmental directives. Graham emphasized that systems should be chosen on the basis of total cost of ownership, rather than on consumable costs, and that increasing power and water costs were significant factors regardless of which system was adopted. He described a “Cost of Ownership Model” designed to provide information to enable customers to make informed purchasing decisions.
Always a popular speaker at ICT events, Enthone’s Frando van der Pas debated the question “Do Green, Performance and Cost go together in PCB manufacturing?” Against a background of relentless environmental legislation and fierce competition, PCB fabricators were striving to reduce costs throughout the whole of the manufacturing process whilst continuing to maintain demanding standards of product quality and performance. Suppliers of chemical processes recognised these challenges and had responded by developing chemistries which were less waste generating, required less rinse water and operated at lower temperatures. Examples were oxide-replacement inner layer bonding treatments with low etch factors and high copper capacity, direct metallisation processes based on conductive polymer technology as technically and environmentally superior alternatives to electroless copper, and lead-free solderable finishes – immersion silvers and OSPs – as alternatives to HASL and ENIG. All of these processes were enabling technologies which offered reduced costs whilst providing significant environmental benefits.
Paul Watson of CEMCO – FSL, another Fellow of the Institute, presented the final paper which focused on saving energy and reducing waste from the equipment supplier’s perspective. In the past, few manufacturers of wet process equipment had been particularly conscious of the need to produce systems that were waste and energy efficient. Equipment development had been driven by panel technology and size, requiring wider machines with transport systems that could convey thinner and thicker product with finer lines, smaller holes and irregular shapes etc. As a consequence, equipment had become more complicated with high operating costs in terms of power consumption and waste produced. Paul reviewed in detail the criteria driving current equipment development: lower volume sumps, improved liquid flow dynamics of chemistry and rinse water, improved fluid containment, more efficient drying systems, integration of controlled water/chemical usage and waste management, and reduced footprint size, and described some of the innovative features of new-generation wet-processing machinery.
In his closing remarks, Bill Wilkie commented that this had been the second successful ICT Evening Seminar to be held at the Devonport Hotel in Darlington this year, both events having been exceptionally well attended. He gratefully acknowledged the support of Gordon Arkley of Faraday Circuits, who had sponsored the event.
Pete Starkeybr> ICT Council
September 2008
First published by I-Connect 007 and reproduced with their permission