Simulation and experimental study on pressure transfer in sand mold digital extrusion process

As a new sand mold forming for patternless casting process, a further study is needed in the extrusion-milling technology. Since the extrusion of sand mold can change the strength and gas permeability, it plays a vital role in the control of shape and performance. To study the law of pressure transfer during extrusion, static and dynamic models of sand particles are developed, and the force transfer mechanism between granular particles is revealed. In this study, the extrusion near-shape process of sand mold with 300mm cavity depth is simulated and analyzed by using discrete element method (DEM). The transmission law of force with 300mm cavity depth under single-sided extrusion is obtained. The deeper the depth of the sand mold cavity, the smaller the force on the bottom of the sand mold, and the more defects in strength and uniformity at the bottom. The correctness of the simulation model is verified by testing the strength and gas permeability of the bottom of the sand mold. This present study provides a research basis for the preparation of high-quality sand mold in extrusion cutting process.