Military, defense, and other electronics products exempt from most environmental legislation are now oft produced with lead-free parts, a concession to the supply-chain-driven obsolescence of leaded materials. Add in deliberate reduction in hexavalent chromium usage; overhauls of facility waste, lighting/energy, and water management; and a focus on lead-free reliability, and you’ll be closer to what a successful environment strategy for the high-rel space looks like. SMT recently toured Cobham Systems in Lowell, MA, which has successfully collaborated with the Toxic Use Reduction Institute (TURI) for 20 years.
In recognition of Cobham and TURI’s 20 years of fruitful partnership, Massachusetts State Senator Steven Panagiotakos called Cobham an “example for other companies in safety and environmental care,” adding that the “concrete results” achieved in the facility were all the more impressive because Cobham’s high-rel status meant there was “no mandate for them to make these changes.”
From 2002 to 2004, there has been an 84% reduction in lead use at Cobham. “It was obvious to Cobham, even as a RoHS-exempt hi-rel company, that the world was going in the lead-free direction, and that lead-free was the right thing to do,” said Dick Anderson, senior principal engineer at Cobham. The company learned how to work with suppliers and assembly houses on a lead-free supply chain; how to test and inspect lead-free joints; and when lead-free is appropriate, and when it cannot be implemented.
“Removing hexavalent chromium and lead from their products has been good for workers at Cobham as well as customers,” said Gregory Morose, project manager at TURI. It is also a costly endeavor to undertake alone, which is why the Cobham facility has collaborated with 30 electronics companies in the New England Lead-free Consortium from an early phase.
When Cobham first tried to move from hexavalent chromium to trivalent, the results were terrible. Learning from TURI’s research techniques, they adapted the process. Now, Cobham has a zero-corrosion trivalent chromium process, and uses hexavalent chromium only when absolutely necessary.
Another prong of Cobham’s environmental responsibility approach is a facility-wide engagement with ISO-14001 (environmental management system — EMS). The Cobham environment, health, and safety (EHS) team — lead by EHS manager Bob Canedo — identifies controllable aspects of the process, rates the impact of said processes, and creates new methods or steps to counteract negative impacts. With complete employee involvement, Cobham’s EHS team has optimized cleanroom airflow and facility lighting to reduce energy usage. Methyl ethyl ketone use was reduced via a switch to ultrasonic cleaning. Simple procedural changes led to cutbacks on acetone and ammonia consumption, and increased waste recycling. Many of these steps can be undertaken at any hi-rel SMT assembly facility. For more on ISO-14001, read TFI's blog post on the subject here.
Cobham’s Reliability Lab: Proving Out Eco Processes
To build high-reliability electronics with the newer materials and processes of lead-free and trivalent chromium, etc., Cobham needs to perform in-depth and long-term analysis. The “problem solver” lab studies solder joints and chemical results in electronics assemblies. Using focused-ion beam scanning electron microscopy (FIB-SEM), scanning acoustic microscopy (C-SAM), X-ray fluorescence (XRF), and other analysis tools, they inspect for signs of lowered reliability or performance, right down to visually evaluating the eutectic structure of a solder. Counterfeit analysis is also possible in the lab.
Thermal shock atmospheric chambers replicate the harsh environments where hi-rel PCB assemblies will operate. Cobham performs highly accelerated life tests (HALT), shock tests, salt fog corrosion, drop tests, acceleration/pull tests, vibration, and temp/humidity tests, all with the goal of finding and measuring the assembly’s weaknesses. Cobham describes the lab as the place where they “beat up assemblies.” Testing can be as specific as dialing in vibration tests to match the environment of a certain helicopter, vehicle, etc. Without this degree of certainty in its manufacturing processes, Cobham would not be able to simultaneously inhabit the high-reliability and eco-friendly assembly markets.
Meredith Courtemanche, executive editor
Questions on moving to lead-free and other EHS projects in a hi-rel environment?
Contact Gregory Morose, project manager, TURI, at Gregory_morose@uml.edu
Robert Canedo, manager of environment, safety, and health, Cobham Sensor Systems, at Robert.firstname.lastname@example.org