Application of Low-Cost Natural Binders in Direct 3-D Printing of Sand Molds

Layered Manufacturing enabled the direct production of sand molds and cores by selective injection of binding agents into sand layer. These binding agents are chemically reactive and have significantly higher cost in comparison to Bentonite clay used in routine foundry work. These binders also need special mechanism for printing and storage which result into increased equipment cost. The present study explores feasibility of using low-cost natural binding agent, orange peel powder as an alternative to chemical binders. A preliminary framework for layered manufacturing of standard sand testing samples employing natural binders is developed. Some of the important mold properties such as mold hardness, mold permeability and green compressive and shear strength are evaluated. The results are compared with standard sand testing specimen prepared using conventional binding agents. It has been observed that the mold hardness and strength properties of layered mold using orange peel powder are significantly better. The outcomes of this preliminary study are quite encouraging and further work will focus on investigating reasons for improved sand mold properties and development of low cost layered manufacturing equipment for direct printing of sand molds.