The main factors affecting the cost difference of precision castings:

Strictly speaking, the production cost of different castings in each process is not completely the same, but the stage difference is not big and can be carried forward according to the average. What people need to care about is that these are more harmful to the cost of castings. Elements.
The key reasons for the gas porosity in stainless steel precision casting:
1. The air permeability of the architectural coating is poor or the negative pressure is not enough, and the air permeability of the filled sand is poor, and the vapor and residue in the cavity cannot be discharged immediately, resulting in pores under the working pressure of the filling.
2. The pouring rate is very slow, unable to fill the sprue cup, exposing the sprue, entraining gas, sucking in the slag, resulting in entrapment pores and slag holes.
3. The foamed plastic solid model is gasified and dissolved into a lot of vapor and the residue cannot be discharged immediately to the metal mold. The dry sand of the foamed plastic and architectural coating layer is not good enough, and it is surrounded by the high temperature of the liquid aluminum alloy. Under the condition of cracking, a lot of radon gas and co2 intrusion into castings are the key reasons for the generation of pores.
4. Because the design of the pouring control system is unscientific, the filling rate of the metal material liquid exceeds the gasification tolerance of the foam and the rate of vapor discharge, which leads to the forefront of the filling to entrap the vaporization residue in the metal material liquid and vaporize again. The inner cavity is soot-black dissolved stomata.
5. The sealing performance of the junction between the sprue cup and the sprue and its pouring system software is not very good, especially when the connection between the sprue and the sprue cup is not well sealed, under the effect of negative pressure It is very easy to produce sand and pores, which can be calculated and expressed by Bernoulli equation.
6. The particle size distribution of the shaped sand is too fine, the water content of the dust is high, the air permeability is poor, and the internal blockage of the negative pressure pipeline causes the negative pressure to fall out of Can be discharged immediately to the plating layer to produce pores or wrinkles.