Dynamic Controls is well advanced in eliminating five of the six restricted hazardous substances, with tight controls over the design, component sourcing, production and end-of-life management procedures - all in advance of regulatory deadlines for compliance with the EU RoHS Directive. The use of Tin-Lead solder (Sn-PB) continues across the mobility product range - being components of medical devices - for technical, safety and reliability reasons, and as permitted by the exemption.
Nevertheless, our Contract Manufacturing arm has proven capability for Lead-Free solder assembly, having trialled a number of different solder alloys, pastes and fluxes, reflow profiles and associated process controls, followed by destructive (microsectioning) and non-destructive (3D X-ray) intermetallic joint reliability testing, both internally and at specialized test houses. The Lead-Free solder assembly process has been trialed on diverse products to gain a better understanding of the critical control points, fine tuned to optimize throughput yield, and to consistently produce reliable joints benchmarked against the Tin-Lead solder (Sn-PB) assembly process.
In the course of the Lead-Free trials at Dynamic Controls a number of technical issues had to be overcome - these included, for example:
- effects of elevated processing temperatures - with associated difficulties such as propensity for component popcorning or tombstoning, board warpage, excessive wicking, etc
- tin whiskers
- micro voids and blowholes
- fillet lifting/ pad lifting/ joint tearing
- board & component finish
- lead contamination
- copper erosion, etc.
The choice of SAC (Tin/ Silver/ Copper) as the preferred Lead-Free alloy has emerged as the most favourable solution for Dynamic Controls' processes and is consistent with the electronics assembly industry norms worldwide.
Tight controls over component sourcing, verification and confirmation of supplier's materials content declarations, change control, supported by adequate resources, infrastructure, data and document controls, and specialized personnel training and periodic auditing - internal as well as third-party - provides contract customers a high level of confidence that Dynamic Controls' Lead-Free solder assembly capabilities are best-in-class and the results at least as reliable as the traditional soldering process.
