1. Design of Sand Core Mould
As shown in Figure 1, the center of part of core I volute is a circular hollow structure, and the parting surface is a highly gradient space complex surface. The core is formed by sand blasting machine. Combining with the structure and equipment characteristics of core I, the lower core 5 of core I is designed as a leverable and possibly automatic return mechanism to realize the molding and demoulding of core I.
As shown in Figure 9, core II is composed of left module 4, lower module 5, right module 6 and lower module core 2. As shown in Figure 10, core III consists of left module 1, right module 2, lower module 4, lower module core 5, lower module core 6 and upper module core 7. Core II and core III are manually molded to facilitate the opening of the mold. The molds are divided horizontally and vertically.
2. Work Process of Sand Core Mould
As shown in Figure 1, core I is molded on a sand blaster.First, the heating rod is inserted into the heating hole. After the die is preheated, the furan resin sand is injected into the mold cavity from the perforation hole in the mode state. During the forming process, the gas in the cavity and the gas generated during hardening are discharged from the exhaust slot. After the furan resin sand is heated and hardened, the hydraulic system of the sand ejector separates the upper mold 3/lower mold 4, and the sand core I remains in the lower mold, which is triggered.After loosening the core I covered by the lower core 5, the lower core I is removed by leverage 7. Subsequently, under the resilience force of spring 13, the lower core 5 returns automatically and is close to the limit surface of the lower module 4. When the upper module 3 and the lower module 4 are combined, a sand core forming cavity is formed.
As shown in Figures 2 and 3, the core II and core III are small. They are manually molded. The upper/lower and left/right structures of the mold are positioned precisely under the guide of the guide pillar and guide pin. After closing, the mold is injected with furan resin sand from the upper opening. After compacting and filling, the mold is baked in the oven. After heating and hardening of the furan resin sand, the mold is removed, and the upper/lower and left/right molds are separated and removed.Core.