Precision casting is a common casting process in steel casting manufacturers, but the current development is not as common as iron castings and steel castings, but precision casting can obtain relatively accurate shape and relatively high casting precision.
The more common way for precision casting is to design the product mold according to the drawing. The difference between precision casting and steel casting is that the steel casting should have a certain margin for processing, while the precision casting can have a margin or not.The original wax pattern is obtained by casting, and then the coating and sanding processes are repeated on the wax pattern. After the hardened shell is dried, the internal wax pattern is melted. This step is dewaxing, so as to obtain the cavity;After baking the shell, we can get enough strength and air permeability. Then we can cast the required metal liquid into the cavity. After cooling, we can remove the shell and remove the sand, so as to obtain high-precision finished products.We can carry out heat treatment or cold processing according to the needs of products.
Investment casting process:
1. According to the requirements of the user's drawings, the mold is divided into the upper and lower concave mold, which is completed by milling, turning, planing and other processes. The shape of the mold pit should be consistent with the half of the product.Because the wax mold is mainly used for industrial wax molding, we need to choose the aluminum alloy material with low hardness, low requirements, low price, light weight and low melting point as the mold.
2. After choosing a good aluminum alloy material, we can use this aluminum alloy to produce a large number of industrial wax solid models.Under normal circumstances, a solid mold of industrial wax can only produce one blank product.
3. When the wax pattern is ready, it is necessary to modify the margin around the wax pattern. After removing the superfluous things on the surface, it is necessary to stick a single wax pattern on the prepared head.
4. We have a number of wax mold head coated with industrial glue, and then evenly sprayed with the first layer of fire-resistant and high temperature resistant silica sand.This kind of sand particles are very small and fine, which can ensure that the final surface of the blank is smooth.
5. Then put the wax pattern in the factory where we set the room temperature for natural air drying, but it must not affect the shape change of the internal wax pattern. The time of natural air drying depends on the internal complexity of the mould. Generally speaking, the first air drying time is about 5-8 hours.
6. When the wax pattern is air dried, a layer of industrial glue is needed on the surface of the wax pattern, and a second layer of sand is sprayed on the surface. The sand particles in the second layer are larger and coarser than those in the first layer.After touching the second layer of sand, as the first layer, carry out natural air drying
7. After the second layer of sand is naturally dried, the third layer, the fourth layer and the fifth layer of sand blasting shall be carried out successively.Sandblasting requirements: we need to adjust the sandblasting times according to the surface requirements and volume of the product.In general, the frequency of sandblasting will be about 3-7 times.The particle size of each sandblasting is different, the sand of each process is coarser than the previous one, and the air drying time is also different.Generally, the period of sanding on a complete wax pattern may be about 3-4 days.
Post time: May-06-2021