The friction surface of a brake disc is generally finished through several machining processes such as grinding and turning. They have gains and losses in braking effectiveness, cost, etc. In some cases, effectiveness is not stable under a certain condition during running-in. This phenomenon is becoming more apparent as non-asbestos organic lining materials have come to be used more widely.
In Part I of this study, brake discs finished through two processes were burnish-tested together with five lining materials that had various levels of aggressiveness. These tests show that a more aggressive lining material needed fewer burnish stops but, as expected, caused more wear. The behavior of friction and wear was found to depend both on lining materials and finishing processes.
In Part II, many discs finished through various processes were tested together with one of the lining materials that showed the largest difference between the finishing processes described in Part I. The test results revealed several criteria for the surface texture (in particular, radial and tangential roughness) of a brake disc.