Study on the application of a granite composite material in five-axis CNC-VMC machine Tool

Abstract

A five-axis CNC-VMC machine tool generally has a high-speed spindle spinning at a maximum rotation of 50,000 rpm, under which the machine tool bed will violently vibrate that leads to poor machining precision and surface quality of workpiece. The gray cast iron, as the typical material of a machine tool, exhibits poor dynamic suppression of vibration that its processing yield and quality can no longer satisfy the product demand of current market. Consequently, in this study, we proposed granite composite material (GCM) in place of gray cast iron for the structure of machine tool, which would be mixed with main ingredients of high-strength epoxy resin and cemented carbon fibers and fillers to maximize the structural properties of the machine tool. The sample of granite composite material would first be tested for its mechanical properties. The results showed that the GCM cast with only 1/3 density of gray cast iron could withstand a maximum compressive stress of 125.8 MPa. With this granite composite material used in a digitally controlled machine tool bed, the maximum stress and the maximum strain exerted on the machine tool were reduced by 68.93% and 72.6%, respectively, when compared with the cast iron, while the 1st to the 6th-order natural frequencies of the machine tool of mineral composite was significantly increased by 20% to 30%, giving it more resistance to vibration than the gray cast iron. The stability and precision of the machine tool were shown to have been drastically improved by using the granite composite material.