With the advent of no-clean fluxes and solder pastes, the need for cleaning electronics assemblies disappeared.
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Or so some would have you think.
But while the masses switched, ahem, en masse, to no-cleans, often in hopes of eliminating what was widely seen as a non-value-added step from the assembly process, a not-so-funny thing happened: Field failures and legislation.
The influx of no-clean coupled with better process control drove the use of cleaning to general consensus of 5% of all boards, mostly for high-reliability applications such as military, certain telecommunications, and aerospace. But the broad switch to Pb-free solders, prompted in large part by the RoHS Directive, and more densely packed boards that effectively turn even trace residues from aesthetic nuisances into potential hazards, has brought about a renaissance for cleaning advocates. And to a degree, suppliers of cleaning materials are, well, cleaning up.
Zestron, one of the perhaps two best-known providers of cleaning chemistry, estimates it has installed more than 1,500 processes worldwide. The company, which has developed several versions of aqueous- and surfactant-based cleaners, plus a line of vapor recovery systems, credits the litany of legislative protocols and directives for having a significant impact on the industry's approach to soldering. "We're definitely seeing an increase in cleaning," says Mark Cherubin, group head of marketing for the Ingolstadt, Germany-based firm. "RoHS, then REACH: The various trends are pushing the issue."
Launched outside Munich in 1975 by Dr. Oskar Wack, Zestron has grown into a multinational corporation with facilities in the US, Shanghai, and its newest site, in Kulim, Malaysia (sidebar). The company focuses its electronics cleaning efforts on semiconductors and SMT. Last year, Dr. Wack turned over the day-to-day operations management to his son, Harald, who is based at the company's Manassas, VA, site. (See "New Zestron Global HQ Takes Flight," Circuits Assembly, June 2007.) (It also has a business unit for automotive cleaners, which Dr. Oskar Wack still oversees.)
At its main campus, about 60 miles north of Munich, Zestron last fall opened a new 30,500 sq. ft. facility, featuring a state-of-the-art, 9,000 sq. ft. analytical and technical center said to be the largest in Europe. The center, which Circuits Assembly visited in November, features a host of testing equipment, including a Gen3 cleanliness tester...