Latest Developments in the High Performance Machining of Cast Iron Brake Discs with PCBN and Ceramic Cutting Materials and Tailored Tooling

摘要

The brake discs and brake drums used on motor vehicles are, in 90% of applications, made from grey cast iron. Although other designs such as composite systems comprising of a grey iron braking band and a light weight mounting bell made from aluminum, Al-MMC or entire ceramic brake discs have been developed, cast iron will continue to play a major role as a work piece material for brakes. Cast iron offers advantages in material characteristics such as good thermal conductivity, high compressive strength and damping capacity. In addition it shows a superior casting behavior and also an unbeatable competitive price per part, when compared to other brake materials or designs. Ongoing research in material and casting science are leading to new types of alloyed CI materials, fulfilling the increasing demands in terms of performance but also increasing the demands for a reliable and economical production. As a product of high volume production the economics and productive manufacturing of the brake discs is a fundamental issue to ensure the competitiveness of the manufacturers. The output and final cost per part are highly influenced by the manufacturing technology, the cutting materials and tooling systems applied. Further development of Ceramics and PCBN (Polycristalline Cubic Boron Nitride) cutting materials, customized tooling and work path planning are the basics for best machining results and minimum manufacturing costs.