Source: Haldex post
LANDSKRONA, Sweden — The benefits of the bright brown metal copper have been rediscovered over the past year: during the COVID-19 pandemic, it has helped reduce the risk of cross-infection in hospitals and care homes, thanks to the metal’s antimicrobial properties.
However, it performs in the same way whether formed into a push plate on a door, or as roadside dust that blows into a stream. Since copper is harmful to fish, wildlife and invertebrates, the U.S. states of California and Washington have decided to limit its use in vehicle brakes starting in 2021 to a maximum of five percent by weight, reducing to 0.5 percent in 2025.
Haldex is one of the first brake suppliers to provide friction materials that, at less than 0.5 percent, exceed the current requirements. It is now shipping the material for disc brakes to the independent aftermarket and U.S. auto manufacturers and plans to supply the same material in Europe in two years’ time after the completion of customer testing.
Haldex: at Your Service
Because European legislation has not caught up with U.S. laws in this area, the low-copper friction material will launch in Europe ahead of any legal requirements. Haldex is truly leading the industry to make friction material more eco-friendly.
Accomplishing this goal has not been easy. As copper commonly accounted for about 10 percent of brake friction material by weight, finding a suitable replacement is of crucial importance. Copper’s primary function within the brake friction material is the same reason why it is used in domestic wiring; its superior conductivity helps draw heat away from the disc and reduce brake fade. (It also works as a lubricant).
This latest change in composition is just the latest change in a long-evolving product. Over the years, a number of materials have been removed, mainly for health concerns, like lead, cadmium and asbestos.
“It is challenging to find raw materials with suitable properties,” points out Jonas Benson, manager of homologation and vehicle testing. “It is one of the most complex manufactured goods, including many different compounds and industrial byproducts.”
In addition, commercial vehicle brake pads need to be more robust than those of passenger cars because the additional vehicle weight. Amounting to more than 40 tons, that translates into inertia, which, when the brakes are applied, generates intense heat.
Explains Benson: “Our testing is worst-case, which is a bad driver down the German Alps. The calipers can exceed 900°C – and the pads are even hotter – but they can’t fall apart. When you apply the pedal really hard, there’s a clamping force of over 20 tons.” To view the entire post, click HERE