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RoHS issues linger
Rob Spiegel -- Design News, December 12, 2005
As OEMs prepare for the July 1, 2006 RoHS deadline, many are struggling with higher manufacturing costs as well as changed manufacturing processes. Some contract manufacturers are charging more to manufacture compliant products, while difficulties with PCB cleanliness and high process temperatures throw up unexpected challenges in the final months before the compliance deadline.
Since the RoHS directive applies to all stocked products on July 1, 2006, OEMs need to be shipping compliant products by mid-spring 2006. That means most OEMs that plan to send products to Europe are presently in full RoHS changeover. One of the unexpected difficulties OEMs are reporting is high costs for outsourced manufacturing.
AFL Telecommunications of Duncan, S.C. was ready for RoHS, but not ready for higher manufacturing prices. “We are on track to convert all of our product lines to RoHS before the July 1 deadline, but we received some shocks when looking over the quotes from out CMs [contract manufacturers] for process builds,” says Dale Eddy, engineering technician at AFL. “In some cases we’ve seen a 200 to 300 percent premium for a lead-free build.”
He notes that AFL was able to find one CM with lead-free costs that were similar to its non-compliant manufacturing costs. “Only one CM we do business with has come in with build quotes on par with our SnPb process builds,” says Eddy. “While we knew there would probably be some increased costs associated with the new process, we never expected that much of a difference. We are still trying to figure out why the big disparity between the two processes.”
Another challenge AFL faced was printed circuit board (PCB) cleanliness. “Since many of our instruments use very high-gain analog circuits, board contamination is of great concern to us,” says Eddy. “This relates to RoHS-compliant boards and assemblies because it is my belief – through reading a number of articles in industry publications – that board cleanliness may have an affect on tin whisker growth.” He notes that “contaminants on the PCB can cause micro-current flows between components or between pins on components, possible promoting whisker growth along the current paths.” Whether lead-free boards will be subject to greater potential tin whisker growth remains an industry controversy, with strong views on both sides of the issue.
Eddy also notes AFL ran into a challenge with compliant connectors that were not able to withstand higher process temperatures. “We came across a few RoHS-compliant connectors that were compliant, but the plastics that made up part of the connector didn’t handle the higher processes temperatures all that well,” says Eddy. “We had to scramble to find a compliant connector that didn’t suffer from that problem.” He notes that a supplier AFL used for non-compliant connectors came through with a compliant version that readily handled the higher temps of the RoHS reflow process.
