Benchmarking Permeability of Investment Casting Shell Molds Used for High-Value Segments Using Smart Measurement

Abstract

Permeability of shell molds for investment castings used in high-valu segments including aerospace, biomedical and defense plays a very important role in achieving better quality castings especially free from filling-related defects. Though, guidelines related to permeability measurement techniques have been established for twenty years, the permeability measurement device is not available in most investment casting foundries. This can lead to issues when establishing foundries to supply investment castings for high-value segments. A specific permeability measurement device has been developed by following guidelines published by a globally accepted standard body that further has been facilitated with the fundamentals of the Internet of Things. Different mold materials (using zirconium sand, aluminum silicate and fused silica) that are used in shell mold making for high-valued segments have been tested for establishing benchmark values of permeability. These values of permeability were observed in the range of 8 × 10^-11–37 × 10^-11 cm² to achieve better quality shells as well as investment castings.