Technological process of lost foam casting

The technological process of lost foam casting is divided into white area and black area.

(1) the process of lost foam white area: the white area is mainly a program for making foam models. The thickness of foaming agent and the original foaming agent should be considered first. After finding the suitable foaming beads, the original beads are put into the intermittent hair machine for foaming. Foaming process requirements should be considered, such as density, strength and other indicators. After drying in the vulcanization bed of the preheater, it is transported to the curing bin for curing. After entering the molding workshop, the matured beads are injected into the preform mold. After being heated and humidified by steam, the beads are expanded and melted to form a casting pattern. Finally, the mold cavity is filled to form a casting pattern. And then through the cooling process, the foaming white mold has a certain strength. Then enter the drying room for drying, and the white mold is finished.

(2) Process flow of lost foam black area: the foundry places the special interlayer sand box on the vibration equipment platform, and then paves the dry quartz sand with the thickness of about 100 mm at the bottom of the box (the grain size of quartz sand is about 20-40 mesh), and then vibrates the quartz sand in the box through the vibration equipment, and at the same time, scrapes the top of the box. Then, the Yellow model made in the white area is pre placed on the bottom sand surface of the sandbox, and the position of the Yellow model in the sandbox is arranged according to the pre design. Then, the reserved model of the runner used in the casting is connected with the pouring riser, and the sandbox is filled with dry sand. Then, the sandbox is vibrated again according to the process requirements. After the sand in the sandbox is vibrated, the dry quartz sand at the mouth of the sandbox is scraped again. After scraping, cover the box with plastic film, and then put the gate cup at the gate. At the same time, fix the plastic film with quartz sand at the edge of the box. Then connect the vacuum system hose to the pipeline at the bottom of the box, start the equipment of the vacuum system for vacuumizing operation, and fasten the dry sand in the box after reaching the specified time and process requirements, so that the mold process in the black mold area is completed. Wait for the metal solution to enter the Yellow mold cavity of the mold box through the gate cup, and then wait for the white mold gasification to disappear, the high temperature metal solution quickly replaces the position of the white mold cavity, and overflows out of the gate, and the pouring procedure is completed. After pouring, the box body should be cooled by maintaining pressure. After cooling, the vacuum equipment should be reset, and the vacuum pumping process for the box body should be cancelled. Finally, the casting should be turned over after cooling, and the casting should be taken out.

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