Smart Group PCB Procurement Day
Feb 20, 2004
On Wednesday I took part in the Smart Group's PCB procurement day at CEMCO in Waterlooville on the south coast of the UK.
When I say I took part, I mean that I drank their coffee, ate their lunch, listened to all the presentations and enjoyed the company of some industry professionals as always – unusually this time I was also a speaker, airing my views on my favourite topic.
Bob Willis, well known speaker, expert and Smart Group promoter, introduced the day. Letting the audience know what they could expect to learn during the day. He was also good enough to elaborate on the good works of the Smart Group, pointing out the news and information they provide on www.smartgroup.org. Bob also alluded to the fact they are in constant search for the topics of importance and indicated that they would welcome information on the kind of topics the delegate would like to have dealt with.
Bob introduced to the room, Peter Starkey, A speaker whom most in the PCB industry are familiar. I am a particular fan of Pete, who has a greater knowledge of PCBs than most could even dream of. He has held the highest positions within the UK industry and is an expert and an enthusiast.
Peter began by telling the room how PCBs were made. The level of detail allowed those present to fully understand both the process and its complexities. I have seen Pete do this presentation before and always enjoy the detail as a refresher of the process steps. Perhaps one of the most important things that the audience learned is that boards are not easy to make. Danger is around every process corner.
Following on Peter’s heels was Dennis Price, who, at Merlin Circuits, takes care of current technology. He added value to the process presentation of Peter’s by elaborating on the tolerances and design rules associated with each step of manufacture. Dennis spoke lucidly on the DFM rules applied and was good enough to show us some of the issues that his company had had to deal with.
I was up next, feeling that Peter and Dennis had all the answers and all I had was questions. My presentation was an introduction to the way in which decision are made when selecting PCB suppliers, wherever in the world they might be. It has always been my view that suppliers and buyers seem to fall over each other, rather than coming together in a more considered and scientific way. The contents of the presentation will form another article to be published very soon.
Following my presentation was a tour of the CEMCO facility, which manufactures the ‘de facto’ Hot Air Solder Levelling (HASL) machine for PCB surface finishing. CEMCO is an impressive company with a market penetration most equipment manufacturers would envy. The tour was made more interesting by the fact that CEMCO run a subcontract service, which allowed us to see machines actually working. This combined with the current status of the lead-free issue added to the value of the day a great deal. CEMCO should be complemented on the support they have given the day as hosts. I thank them for a first class lunch as well as an excellent conference room and facilities.
Most would have been happy to continue enjoying CEMCO’s hospitality into the afternoon, but no, Bob insisted we re-take our seats to listen to further presentation.
The afternoon began, as the morning did, with an informative presentation from Peter Starkey. Peter talked in detail about the effects of the lead ban on the PCB manufacturing process, detailing finishes, such as that shown on the factory tour by CEMCO’s staff. CEMCO are now producing good lead-free HASL finishes using tin-copper-nickel, in their standard equipment.
As Pete sat down, Bob leapt up to tell us about the issues that need to be considered by the assembler. Bob talked about the problems faced in hand soldering, wave soldering and adhesive application and curing, offering solutions in each area. Dealing with such problems as board-sag in a practical way. Bob’s presentation gave a very balanced and positive view to dealing with PCBs after July 1st 2006 (Lead-Free Day). The problems Bob had seen seem to relate to board quality rather than lead-free assembly techniques, perhaps tolerance of poor PCB quality will become an
issue of greater importance.
Bob continued straight on to his second presentation talking about how finishes perform. The analogy that "nothing solders better than solder" was again used in support of the HASL finish. Again with the caveat that many HASL finishes are not controlled well enough. If HASL is the answer, fabricators will have to learn how to manage this process better.
Lead-free also creates exaggerates the problem of expansion, resulting in greater concern with pad lift, again a problem that had been largely cosmetic and no hard failures had been seen as a result. Bob also flagged copper removal as a potential problem.
There followed a lively Q&A session on the lead-free assembly of various board types. Managed confidently by Bob, who answered most of the questions and fielded the rest.
It seemed all in all most delegates got what they wanted from the day – going back to their offices with food for thought at the very least and hopefully with some ammunition and contacts to deal with the issues in hand.
Following a tea break, in which many interesting topics were discussed, Bob talked more about the processes he recommends when auditing a PCB shop. Accountability came up. Bob suggested when they offer a technology road-map, that you ask for the road-map from two years ago and see what they actually achieved…
The afternoon was rounded off by a second Q&A session when the audience raised some important issues about the where the responsibility for lead-free content lies. Bob’s interpretation was that it lied in the hands of the supplier, and if he asked for a C of C stating a PCB was lead-free he had probably discharged his responsibility. Bob did suggest testing and some method were discussed. Bob also referred the audience to various websites that contain information on this topic.
Bob thanked the participants, the speakers and our hosts, CEMCO. As the audience were departing I was able to garner some feedback and it seemed that most had got a good deal from the day.