Optimization of mechanical and thermal expansion properties of resin mineral composites for ultra-precision machine tools

Resin mineral composite (RMC), composed of granite aggregate, fly ash, epoxy resin, etc., has been widely noticed in the field of ultra-precision machining by its excellent vibration damping performance. However, RMC’s application is limited by its low mechanical strength. In this paper, two aggregate gradation schemes, containing fractal aggregate gradation (FAG) and coarse aggregate broken gradation (CABG), are designed before researching the effects of aggregate gradation schemes, maximum aggregate size, resin dosage, vibration time, and defoaming agent dosage on the mechanical properties, porosity, and coefficient of thermal expansion (CTE) of the RMC. Shown by the experimental results, CABG has a better performance than FAG both on their mechanical properties, porosity, and thermal expansion properties. FAG and CABG’s compressive strength and elastic modulus reach their maximum values at the resin dosages of 10 wt% and 9 wt%, respectively. Their optimal vibration times are 40 min and 30 min, and optimal defoaming agent dosages are 1.5 wt% and 1.0 wt%, respectively. With the optimal preparation process, 100°C RMC’s compressive strength and elastic modulus increase by 23.8% and 8.6%, respectively, and its CTE decreases by 58.4%. By this research, the resin dosage, vibration time, and RMC’s manufacturing cost would be effectively reduced, thus improving RMC’s application in ultra-precision machine tools.