High-Precision Brake Discs to Reduce Judder

The necessity of a high-precision disc to reduce brake judder was reconfirmed from the three viewpoints: a literature review, experiments, and bench marking. Geometric accuracy is the critical issue that brake disc suppliers must address to improve the NVH performance of automobiles. We have achieved disc lateral runout of less than 20 micrometers after rough and semi-finish turning operations by increasing the rigidity of lathe components and tool holders, improving work-holding devices, selecting appropriate cutting insert material and geometries, and optimizing cutting conditions. With an additional grinding process, by selecting the most suitable abrasive wheels, optimizing grinding conditions, and keeping the alignment of the work-piece and grinding-wheel spindles accurate through productive maintenance based on the in-line measurement data, we can correct the geometric dimensions of the disc friction plates to obtain higher accuracy. As a result, we can provide brake discs with geometric accuracy of 5 micrometers in disc thickness variation.