Research on Fiber-Reinforced Selective Laser Sinter-Coated Sand Mold

The selective laser sinter-coated sand mold is an appropriate choice for the production of castings with intricate shapes. Nevertheless, the low strength of the initial blank renders it challenging to withstand the external force harm that is a result of cleaning and transportation. The dimensional deformation of the casting results from the low strength of the mold during the pouring of molten metal. In this study, the orthogonal experiment was implemented to determine the laser sintering parameters. Then, the optimal curing parameters were determined by designing a single-variable experiment for curing time and curing temperature, respectively. Ultimately, the fiber-reinforcement experiments were carried out using basalt fibers as the reinforcing phase. The tensile and bending strengths of the initial blank and cured specimens were tested. The results indicate that the specimen exhibits the most favorable mechanical properties when the scanning speed is 2400 mm/s, the laser sintering power is 35 W, and the preheating temperature is 70 °C. The tensile and bending strength of the specimen can attain 7.66 and 15.99 MPa, respectively, reaching their maximum strength when the curing temperature is 220 °C for 150 min. The maximum strength is achieved when 0.1% of the fiber is incorporated. The tensile strength and bending strength of the initial blank are increased by 16.2 and 22.4%, respectively. The tensile and bending strengths after curing are increased by 10.5 and 7.8%, respectively. When the specimen is subjected to a force, the fibers absorb a portion of the burden through debonding and fracture, thereby providing reinforcement. Nevertheless, the reinforcement effect is significantly diminished, and the effect on collapsibility is negligible as a result of the attenuated bonding force that results from the high-temperature casting of the fiber and resin.