Sand Casting Dimensional Control

Abstract

Dimensional accuracy and variability are critical factors in the casting process that must be considered at each stage of the process. Dimensional accuracy is an indication of how close a casting dimension is to design intent (the actual target value). Dimensional accuracy is often referred as a system error. The main causes for poor dimensional accuracy in sand casting are pattern equipment errors, pattern wear, and casting contraction uncertainty. When properly understood and controlled, system error can often be corrected before production runs. Dimensional variability is the variation of individual casting dimensions about their mean. Dimensional variability is often referred to as random error. Many foundry process variables such as placement of cores and sand consistency contribute to dimensional variability.