Dimensional variations of castings and moulds in the ceramic mould casting process

Ceramic mould casting process produces high precision castings at a relatively low cost for the production of small number of parts, making it particularly suitable for producing moulds and dies. There is a constant demand for improving the process capabilities including dimensional accuracy and consistency. In this study, dimensional changes and variability of ceramic moulds and steel castings (P20) have been investigated using a pyramid-shaped part. It was shown that the accuracy of the ceramic mould plays a dominant role in obtaining tight casting tolerances. It was also shown that the dimension, location and orientation of a feature on the part had significant effects on the overall linear dimensional changes as well as the dimensional variability of the ceramic mould and the casting. The complex dependence of dimensional variations on feature orientation and location on the part has been discussed on the basis of asynchronous burning on the mould cavity surface at different locations during the burning-out process.