Machining of Advanced Materials for Automotive Components

Particulate reinforced metal matrix composites (PMMCs) based on aluminium alloys are used in automotive industry because of their low cost and improved mechanical properties at high temperature. Automotive producers are testing prototypes in aluminium PMMCs such as brake disk and drum, callipers, piston and cylinder liners. For many components the production of a good surface finish is essential and therefore will necessitate some machining. The presence of hard abrasive ceramic particulates results in rapid tool wear and high machining cost. Today, this cost effective problem is the main obstacle to aluminium PMMCs wider acceptance in the automotive market. Machining practices have not been optimised, but some studies has stated that roughing with carbide tools (especially uncoated WC tools) and finishing with polycrystalline diamond (PCD) tools are the most economical way in machining aluminium PMMCs. This paper presents results about the factors affecting tool wear when machining with different carbide tools, in order to estimate their influence in the cost of machining this class of materials.