Advancements in Materials for Three-Dimensional Printing of Molds and Cores

Three-dimensional printing of sand molds and cores is changing the way castings are produced. During the last 5 years major advances in equipment have allowed metalcasters to realize casting designs at faster speeds than ever before. The elimination of tooling for mold and cores assemblies has allowed the industry new flexibility in design optimization, reduced labor, increased dimensional accuracy, and eliminated some defects associated with core assembly. While the equipment has been advancing, the materials used for printing have been very limited. The University of Northern Iowa has conducted new research into increasing the number of materials available for printing. These materials include regionally available resins, aggregates, and additives. These new materials have the ability to reduce the cost of printing and increase the number of applications while improving the casting quality. Veining defects in heavy iron or steel castings once prevalent on printed sand molds can be eliminated with engineered sand additives. Solidification rate and penetration defects can be addressed with specialty molding aggregates. This research has allowed the users of printed sand molds and cores to realize the potential of their sand printers and improve the quality of the castings they produced. The paper will detail the experiences with regionally available materials and compare their properties and performance with conventionally supplied materials.