Quality assessment of expendable patterns in the investment casting process

The article presents the basic attempts at expendable patterns quality assessment, such as hardness test, creeping resistance tests and the assessment of patterns mixtures contraction as a function of solidification module. These features were verified on step-shaped pat-terns. Patterns mixtures made on the basis of hard waxes were selected for tests and compared with the domestic mixture based on paraffin and stearin (PS) as well as with the PS-mixture to which the material of used patterns from the WSK Rzeszow factory was added. The selected tests enable a quick assessment of whether the pattern mixture quality meets the requirements of optimum size accuracy and good quality of casting surfaces.