Advanced Polymer Matrix Composites Machinability and Machining Applications

Composite materials are made of two or more materials providing for properties that could not be obtained from any one material alone. One of the materials performs as the matrix and at least one other material as the reinforcement. Composites can be broadly classified on the basis of their matrix material: polymer, metal, and ceramic matrix composites. To date, the largest number of composite material industrial applications involves polymer matrix composites and their machining behaviour represent the main focus of this paper. Composite materials belong to the category of difficult-to-cut materials due to the fact that their structure is anisotropic and non-homogeneous and their reinforcing constituents are highly abrasive by nature. These severe machining conditions can lead to critical damage to the final composite part and determine very high wear rates of the cutting tool. Conventional machining processes such as turning, drilling and milling can be readily applied to polymer matrix composites, provided proper tool design is carried out and optimised operating conditions are selected. An outline of the main machinability issues, problems and solutions relevant to applications of conventional machining processes to advanced polymer matrix composite materials is presented.