SMART Events

Over 200 delegates packed into the Wycombe FC/London Wasps Business Centre for the 7th Annual Lead-Free Seminar and Exhibition. The format this year was different, allowing 8 presentations from experts in their field covering: legislation, design for lead-free, pcb's & finishes, components, materials, equipment, reliability, recycling. Each presentation was limited to 15 minutes, to concentrate on the update status of the subject. Both morning and afternoon sessions were followed by a debate loosely based on the BBC programme 'Question Time' with all panelist's featured plus James Lingard from DTI.

This event was part of the European LEADOUT scheme and Sandra Estanislau, from ISQ - Institute de Soldadura a Qualidade, Portugal, was present. The annual lead-free survey was conducted during the day and these results are now available to members of the Group to download in the Members Area as are all the presentations.

FULL PROGRAMME DETAILS

Introduction - Peter Swanson, Intertronics/Dynamix

Practical Legislation Issues - Nigel Burtt, Dolby Laboratories

Whilst removing lead from our soldering processes is what most of us have been focussing on in the main, the RoHS and WEEE Directives go further than that and it is important to understand the implications of their transposition into national law in the EU member states. This presentation summarised the way the Directives are proposed to be implemented into UK law, including any pending or possible revisions, and the impacts on our businesses.

Design and Layout for Lead-Free PCBs - Bob Willis, Electronic Presentations Services

Lead-Free assembly creates challenges for all design and process engineers, but what are the main considerations to maintain existing yields? Bob Willis demonstrated changes in the industry and what positive results have been achieved. There have been many suggested design changes like changes to PCB materials, increased stencil apertures, drainage pads, board support strips but can the cost be justified?

In the main there are few real changes, just opportunities to improve on existing design to increase manufacturing throughput. Often existing design rules can be modified to offer even higher yields with lead-free assembly.

PCB's & Finishes - Martin Goosey, Rohm Hass

The move to 'lead-free' has important material and process implications throughout the whole electronics manufacturing process. One key concern is the use of the elevated soldering temperatures that will be required with the most popular lead-free solders. These higher temperatures can cause problems with printed circuit board laminates and the correct choice of substrate for a particular application will become increasingly important. The solderable finish that is used on a circuit board will also have to be lead-free and thus the use of tin-lead based Hot Air Solder Levelled Finishes will no longer be possible.

Alternative finishes are both available and well established, but many of them have their own limitations which must be fully understood if a successful soldering is to be achieved. This presentation discussed the implications of lead-free assembly in terms of printed circuit board material and solderable finish choices and highlighted some of the issues that can occur.

Components - Vincent Synnot, Flint Distribution

As we approach the 2006 deadline the component issues are becoming more logistical than technological. We need to be to able identify both physically and on the bill of materials compliant components. Also to ensure process compatibility, reviewing storage and handling issues. Consideration also needs to be given to availability issues, increased obsolesce and the growth in counterfeit components.

A one hour Question Time followed - 'Ask the Experts' (Chair Peter
Swanson)

Materials - Steve Dowds, Henkel Technologies

The higher the process temperatures required for Pb-free soldering have profound impact on assembly materials. Steve outlined changes in materials such as solder paste, fluxes, chipbonders to cope with these higher temperatures & typical process issues which may be encountered during the changeover period. There are also some new developments in the area of alloys for high-reliability applications which was discussed.

Equipment - Gerjan Diepstraten, Vitronics Soltec

The Lead-Free reflow process window is narrower than that of tin/lead. The presentation covered how to keep your reflow process optimized, in control, and flexible enough to keep an open "process window" in the face of these process challenges. Also included were Lead-Free process considerations including temperature, Delta T, throughput, footprint, cooling rates, nitrogen usage, and other key process variables.

Wave soldering with Lead-Free alloys continues to advance. Gerjan assisted in identifying and understanding critical process problems including poor yield, fillet lifting, decreased wetting, costly dross, and the leaching of metals into the solder pot.

Reliability & Implementation - Alan Brewin, NPL

Here current advances in NPLs lead-free projects were outlined.

LF Solder Creep - The creep of Tin-Lead solder during thermal cycling of electronic assemblies is well understood. New work highlights fundamental differences in the behaviour of SAC LF alloys in that they exhibit primary and tertiary creep under typical loading regimes. Microstrain Model Joint Tester - NPL has developed a new test system for measuring the micro-strain data on model joints to create data for solder creep damage prediction models. Low Lead Level Contamination - Images of contaminated joints, and progress of our important LF Transition Project. LF MicroVia Reliability - A new project in this area is imminent, It is an opportunity to be involved.

Recycling - Alan Dukinfield, RID UK

The UK is not the best in Europe at Recycling but legislation is ensuring attitudes are changing to support a more sustainable future. In the Electrical/Electronic sector the WEEE directive is at the heart of this. This presentation looked at the directive from the B2B perspective, to show what producers need to do to ensure practical compliance and look at the treatments available currently.

End of session Question Time - 'Ask the Experts' (Chair Peter Swanson)

(Note: James Lingard from DTI was also a panelist)