The precoated sand casting process includes the following steps:
1. Prepare raw materials: choose suitable sand and resin, and mix them as required.
2. Prepare the mold: Prepare the mold for the required product.
3. Apply mold release agent: evenly apply a layer of mold release agent on the inner surface of the mold to prevent the sand core from being difficult to remove.
4. Core picking: place a mandrel in the mold and fix it to form the required cavity or cavity.
5. Sand core injection molding: inject the mixed sand material and resin into the mold, fill the cavity or cavity, and vibrate the mold to remove air bubbles.
6. Curing: Wait for the sand core to cure, usually it takes several hours to a few days, depending on the size, shape and curing agent of the sand core and other factors.
7. Take out the core rod: Take out the solidified sand core and the support structure at the same time.
8. Surface treatment: According to the need, the surface treatment such as grinding can be carried out on the sand core for subsequent use and operation.
9. Film coating: Apply a layer of resin coating evenly on the surface of the sand core to form a protective film.
10. Drying: Place the coated sand core in a ventilated place and dry the coating resin to harden it and form a solid protective layer.
11. Completion: After all steps, the sand core is ready for mold injection molding.