Dimensional Stability of Mineral Cast for Precision Machinery

Abstract

AbstractPrecision machinery employs a variety of materials for their structures: cast iron, welded steel, natural stone, ultra-high performance concrete (UHPC), and mineral cast (MC). Mineral cast is a composite material with an epoxy matrix and various aggregates as a filler, and has been successfully employed for precision machinery structures for over 30 years. For this work, mineral cast specimens were tested by completely immersing them in fluids, so that the conditions to which mineral cast is exposed during the operating conditions of the precision machinery can be simulated. Test specimens with standard dimensions of 80 × 80 × 400 mm were first immersed in demineralized water or grinding oil for 900 h and then dried for 800 h in a climate test chamber at constant ambient conditions of 20 °C and 50% air relative humidity. The change in length of the mineral cast specimens during the drying period was recorded. The shrinkage of the samples was measured by the difference in the length of the samples before and after the drying process. The water and grinding oil soaking tests show that their influence must be considered in case of high-precision applications, as their effects could be directly comparable to minor thermal variations.KeywordsMineral castPrecision machineryDimensional stabilityMaterial coating