Optimization of an industrial friction material formulation

A Golden Section optimization approach coupled with relational grade analysis was proposed to optimize friction material formulations. It was applied to enhance friction coefficient (mu) for a commercial friction material formulation (IFC) consisting of copper chips, steel wool, Al2O3, styrene-butadiene rubber (SBR), graphite, coke, CaCO3, ZrSiO4 BaSO4 and phenolic resin using the Friction Assessment and Screening Test (FAST). The IFC was used in a popular, commercially available car and it has an average mu of 0.372 and a total wear of 5.70 wt. %. All raw materials used were divided into a metals group, a non-metals group and a binder group. The optimization process was performed in three phases. In phase 1, the optimal proportion of the ingredients within the metals group and the non-metals group was searched. In phase 2, the optimal proportion between the metals group and the non-metals group was investigated and in phase 3, the optimal proportion between the binder group and the metals plus non-metals groups was determined. After 19 experiments, an alternative friction material formulation using identical constituents but optimized was obtained. This friction material exhibited an average mu of 0.535 and a total wear of 6.24 wt. %.