The casting process design involves the process design of the part itself, the design of the gating system, the design of the feeding system, the design of the vent, the design of the chill system, the design of the special casting process, etc.
The process design of the part itself involves the design of machining allowance, pouring position, parting surface selection, casting process parameter selection, dimensional tolerance, shrinkage rate, draft angle, correction amount, parting negative number, etc.
The pouring system is the channel that guides the molten metal into the mold cavity. Whether the pouring system is designed properly or not will have a great impact on the quality of the castings and easily cause various types of casting defects, such as: insufficient pouring, cold isolation, sand washing, Casting defects such as slag inclusions, sand inclusions, etc. The design of the gating system includes the selection of the type of the gating system, the selection of the position of the inner gate, and the determination of the cross-sectional dimensions of each component of the gating system. In addition, the choice of gating system is also very important, so how can we choose the correct gating system?
For mechanized assembly lines and mass production, in order to facilitate production and help ensure the quality of castings, the inner runner is generally set at the parting surface of the casting mold. According to the casting position of the casting blank and the selection of the parting surface, the inner casting The channel opening at the parting surface of the mold belongs to the “middle injection” gating system. Liquid metal will inevitably contain a certain amount of “slag” during the pouring process. In order to improve the slag retaining ability of the pouring system, it is suitable to adopt a “closed” pouring system.
In the casting process, the design of the casting process has a great influence on the quality of the cast product, but the choice of the gating system selection method cannot be ignored.
The design of the feeding system is a reasonable design of risers and subsidies to compensate for the liquid and solid contraction of the casting during the solidification process to obtain a sound casting.
The vent hole is used to discharge the gas in the cavity, improve the filling capacity of the molten metal, eliminate the supercooled molten metal and scum filled into the cavity first, and can also be used as a sign to observe whether the cavity is full.