A Joinery-Based Approach for Segmented Casting Molds Manufactured using 3D Sand Printing

Three-dimensional sand printing (3DSP) is an emerging additive manufacturing (AM) process. 3DSP has potential for producing complex casting molds that were previously unfeasible with traditional sand or investment casting. However, a limitation of the process is the restriction of casting volume due to limited 3DSP print sizes. To overcome this limitation, a modular, joinery-based, self-interlocking 3DSP casting mold system was developed with minimal traditional casting mold restraints. The mold system was demonstrated by metalcasting a representative A356.2 aluminum alloy cylinder under several parameterizations of a dovetail joint design. Data were collected for relevant casting metrics as a function of joint parameterizations, including volume, percent volume of excess material (mold flash), and volumetric shrinkage. The data were statistically analyzed to determine the impact of the joinery design on the quality and characteristics of the 3DSP molds and resultant metalcastings. The joint design parameters of the angle of the mold-mating faces and the length were found to have little to no effect on the differences in percent volume of flash, shrinkage, and density (or porosity). However, joint design plays a critical role in ease of assembly. These findings will aid the creation of larger-than-printable, complex, multi-piece self-interlocking casting molds without adverse effects to the quality of the resultant metalcasting.