Source: The following is excerpted from a Commercial Car Journal post by Jason Cannon on the impact of government mandates regulating copper used in brake pads on the trucking industry.
WASHINGTON, D.C. – Effective with the coming year, brake manufacturers will be required to reduce the amount of copper used in their friction material to meet the copper-free brake pad agreement reached in 2015 between the U.S. Environmental Protection Agency, California and Washington State, and industry representatives.
The agreement calls for reducing the amount of copper used in brake pads to less than 5 percent by weight (B-Level) on Jan. 1, 2021, and 0.5 percent (N-Level) by Jan. 1, 2025. The initiative also reduces mercury, lead, cadmium, asbestiform fibers and chromium-six salts in brake pads.
“Copper provides good thermal conductivity and heat dissipation to brake pads,” said Dhawal Dharaiya, engineering supervisor for Hendrickson Wheel End and Braking Systems. “In addition, copper plays an important role as a solid lubricant that helps generate a friction film during braking application to provide good wear characteristics. Materials that will eventually replace copper in brake pads must fulfill the complex properties that copper demonstrates in current formulations.”
ZF Commercial Vehicle Controls Systems Division Engineering Director Dirk Wohltmann added that since copper wears and oxidizes at high temperatures, it helps provide for better overall pad wear.
Because copper generally is softer, it impacts rotor wear to a lesser degree than other metals, said Keith McComsey, director of Air Disc Brake & Systems for Bendix. “The reduction in copper for future pad formulations will have to be replaced with other materials that do a similar job without adversely affecting the pad friction performance,” he said.
Joe Kay, director of Brake Engineering for Meritor, said a brake’s friction formula has many compounds that make up a sophisticated recipe. Copper replacement in brake pads remains a topic of ongoing research, and many of the replacement materials and approaches to formulations are proprietary.
The one constant that all manufacturers face is that stopping distance laws have not changed. New materials with reduced or no copper must meet current laws, and those updates will need to come without sacrificing component life.
“Wear and life of new pad materials will be dictated by new ingredients replacing copper,” Dharaiya said. “Apart from formulations, wear life is always subject to a variety of factors, such as driving habits, environmental conditions, duty cycle and tractor-trailer brake combination, among others.”
The entire, extensive review of the pending situation, can be viewed b clicking HERE.