Smart Group Leadout Conference High Wycombe, November 1, 2005
Smart Group Leadout Conference High Wycombe, November 1, 2005
Keywords: Electronics industry, Soldering
Eight months to go, and it showed. The Vere Suite at Wycombe Wanderers Football Club HQ in High Wycombe was full to bursting, and whilst we said last year that they should book the Royal Albert Hall for this year, we would have settled for the Wigmore Hall at least. Some 210 people this year, about 50 people when we first attended three years ago (Plate 5).
Plate 5Some 210 people attended this years smart group lead out conference
Bob Willis introduced a series of speakers, all of whom are experts in their own field. Leading the way and from the DTI was Steve Andrews who gave very much a re-run of what the DTI was involved with, and there was absolutely no harm in looking at the facts. Always worth noting what the words homogeneous materials means – it means a material that cannot be mechanically disjointed into different materials. Looking back at the MCVs was useful, as was mention that the European Commission is still running exemption hearings, the third batch looked at 19 exemptions, and batch 4 is looking at no less than 23 cases for exemption, reporting on 28 October. Known exemptions are spare parts made for equipment before July 1, 2006. It is all on www.dti.gov.uk/sustainability/weee/index/html.
In the UK RoHS Enforcement will be the responsibility of the National Weights & Measures Laboratory, whose Chris Smith came to tell the meeting how they would operate. There is no requirement for any declaration of conformity or CE, but there is a requirement of evidence for compliance, and a requirement for products to comply and yes, there are penalties: a fine of up to£5,000 in a magistrates court, and unlimited fines can be imposed by a High Court.
Many exemptions are not included in the UK regulations nor yet effective. The NWML policy is to follow Commission FAQs and DTI guidance, but there is no transition period. Their Enforcement Policy is to be supportive of UK producers and industry, rather than draconian, after all we are all looking for a clean UK(aren't we?). Their general approach will be to do sampling based on risk, with evidence requests; we will review those and move forward on them. Manufacturers will in fact carry out own assessment – once NWML asks for information,the manufacturer will respond, the NWML will assess the response, and take action if at all necessary.
Amongst the many questions from the floor were:
Is there a transition period?A. No.
When is a product deemed to be placed on the market?A. Refer to Blue Book. It applies to each individual product. On the market means at the point of the first legal transfer, it is not sufficient if it is just “on the shelf”.
What is due diligence?A. It is an added layer of protection for you,it is common in trade product and safety legislation, and covers all reasonable steps that you have taken, there is no prescribed “right approach”,and size does matter.
What does primary function mean?A. It is the reasons for the products existence, the reason why it is being bought. It is not for its value added properties, and here any manufacturers marketing and sales departments may need to education.
Enquiry line: 0208 943 7227, web site: www.rohs.gov.uk
Nick Mair is the Sales and Marketing Manager Europe of JJS Electronics Ltd., who are contract manufacturers based in the UK and the Czech Republic. Founded in 1983, they have 243 staff and manufacture for the transportation, medical, industrial aerospace and communications sectors. How does legislation effect them? The WEEE directive has little impact, but RoHS that has the greatest impact. Lead is directly used within the JJS manufacturing process, and there may be some components and materials that contain hazardous materials. So they formed an implementation team, having found that some of their customers really not aware of implications.
Nick described their framework, how they had looked at the legislation, their own systems, the consumables (all materials), the manufacturing process and equipment, and the needs for training and assessment. JJS make 200 different types of product, and have 30,000 different part numbers, so you begin to see the scale of the operation. And add to that the fact that 70 per cent of their customers think they are exempt! So they will be running the two systems (lead and lead/free) side by side, and will use one customer model as a benchmark by which others are converted.
Evaluation will comprise taking a high running product, selecting two finish's (ENIG and ENIS), buy alternative RoHS components as necessary, conducts trials with a SAC alloy, look at the customer evaluation of the resulting assembly, then test products against existing specification, and finally assess reliability and other physical tests. Nick concluded by thanking both the Indium Corporation and the Welding Institute for their support.
Bob Willis then talked about the Lead out Project, which had covered reliability testing, was running training courses, and was looking at process improvements, they were being partnered in this by Margarida Pinto of ISQ,e-mail: mmpintio@isq.pt and Simon Mason at TWI, simon. mason@twi.co.uk.
Ron Lasky of The Indium Corporation had flown over especially for this conference, and in his paper he said that on any one circuit board there could be 40,000 points where you would need to show RoHS compliance. How to handle such a problem? Well, you could use handheld X-ray scanners but it can tell if you fail, but not if you pass! They are expensive and the resolution is in millimetres. Or you could use a SEM, but SEM equipment costs $100,000 and cannot tell the difference between Chrome 3 and 6, and it cannot quantify PBDEs, e.g. 0.1 per cent Br is not 0.1 per cent PBDE. So for full “due diligence”you need to get a materials declaration from your suppliers, and you use SEM/EDX of a “statistically significant” number of locations, and excise material from several solder joints, take a sample of the PCB, and other critical sites. For chromium values you could use ion spectroscopy. Chrome 3 is difficult to find anyway, let alone use. There is no quick solution to a quick analysis of an assembly.
Then came a Q&A Session during which the questions flew aplenty and the varied answers bounced back from the panel. What did we learn from what we heard?
We heard that it is the producer of the equipment, not the manufacturer of the equipment, who has to ensure that the Bill of Materials (BoM) is RoHS Compliant.
We were told that the best alloy for wave soldering is SAC 305.
.Where legacy products are concerned, to ensure that they meet RoHS they will have to be re- designed.
Where a company in the UK imports, say, control instruments from the USA to sell in the UK, will those instruments be RoHS compliant? Yes. The US company will need to comply with the RoHS legislation.
What did emerge was the comment from Ron Lasky of the Indium Corporation that a significant number of companies in the USA were not prepared for the need to meet RoHS compliance, and would probably lose out significantly if not fatally, as a result.
Overall, the words “due diligence” seem to be key, but perhaps the words “be fully informed” would be equally apt.
It is the producer who has to ensure that the whole BoMs is RoHS compliant.
Meeting RoHS compliance has been the most disruptive event in the history of the electronics industry.
Joe Belmonte of Speedline Technologies. jbelmonte@speedlinetech.com knows a thing or two about the reflow process, and suggested to those present that you should allow the solder paste to do what it is designed to, and understand the temperature tolerance of every component on every assembly. Thermal profiling becomes critical; you also need board support with wide or thin panels, and ones with low Tg. In caring for your oven, flux residue may be more difficult to remove; the kit will run hotter anyway, and you will need to lubricate more often. Nitrogen reflow is good, for several reasons. Speedline had run a comparison between some lead-free and some tin-lead pastes, and found the wet back better on tin-lead. They had looked at increasing energy costs, but the latest ovens were more efficient, of course.
In pursuing a transition strategy, the points to consider were numerous– does my existing equipment work well enough, what are the parameters I need to consider? Joe talked us through the process window for lead-free soldering, and mentioned the corrosion with lead- free, so perhaps think about cast-iron which is not corrodible with lead-free alloys. The quick-change solder pot is a good idea for those running two solder systems. Conclusions: main concerns are the narrow process window, but SAC alloy is now the predominant material.
Gary Nevison of Farnell is the Chairman of AFDEC RoHS Group, and from the component perspective he gave an illuminating paper. There is £100 million of non-compliant stock still in warehouses, and his industry has to deal with the costs of holding this stock, of writing it all off, with the 40,000 new products we have to invest in, and the increased costs to distribution. The loss of revenue due to obsolescence is some £750,000 annually for his company alone. There is no standard Certificate of Conformity, they have their own, and Gary looked at all the obligations on the producers. Distributors who are producers are responsible for ensuring that their product did not contain the six restricted substances. He looked at the reality of component testing, and whilst there is a big debate on order coding, at Farnell they just changed everything. It was easier.
Martin Morrell of Circatex talked about PCB materials for lead-free environment. Well aware of all the implications. Are my existing laminates suitable for lead-free? Martin explained why just selecting a High Tg material for lead-free on its own was not a good idea necessarily. The move from dicy cured to phenolic curing systems has improved controls over temperature stress. IST testing is interconnect stress testing, which can show the profile of the board during assembly processing. The number of thermal excursions matters– say two in HASL, then a pre-assembly bake, reflow side 1 then reflow side 2, then lead free wave solder, etc. 11þ thermal excursions! They have found that IST as an accelerated test is most effective, and shows more efficiently where many faults may lie. IPC-TM- 650 is the approved test method. Phenolic cured boards appear to be much better for the stresses induced by leadfree soldering temperatures. There is much you can find out for yourself,but if you need some help then contact: martin. morrell@circatex.com
Chris Hunt of NPL came to talk about the reliability issues in lead-free. It depends on you! It depends on your assembly, your expectations,the service conditions, and of course the process window is smaller. A very detailed presentation, that indicated clearly that there were many problems to be considered, especially where an increase in time and temperature posed a threat to components. They have done a lot of work at NPL, and concluded that it is difficult to get voiding with lead free. Another helpful paper, even more to be found on www.npl.co.uk/et/studio
Whiskers – difficult to predict, looking at nanoindenting tool, Fatigue– strain can cause unreliability. There are a number of potential pitfalls, an investment in process knowledge and performance shows that they include fatigue, transition issues, PCB robustness, tin whiskers, we can reduce the probability of failure.
Summary – quite how the industry would manage with the SMART Group is anyone's guess, but given the immense task they have undertaken in getting the subject of lead-free to the attention of those who matter, one suspects that without them the industry would be in a parlous state of unreadiness by 1st July next year, and a great deal of business would have left the country. As it is,one the industry might well attract overseas orders on the strength of their readiness, and the accolades for that should go the SMART Group.
John LingAssociate Editor, Soldering & Surface Mount Technology
