The design of sprue cup is a key link in casting process, and its rationality directly affects the quality, production efficiency and cost of castings. The following are the main factors to be considered in the design of the sprue cup:

I. Structure and shape of castings

Complexity: If the casting structure is complex, multiple sprue cups are needed to ensure that molten metal can fill all parts evenly.

Size: The size of the casting determines the capacity and size of the sprue cup. Larger castings require larger sprue cups to hold enough molten metal.

Wall thickness: the wall thickness of the casting will affect the flow speed and filling time of molten metal. Thin-walled castings need to design more reasonable sprue cups to avoid rapid cooling of molten metal.

II. Characteristics of molten metal

Fluidity and viscosity: molten metal with good fluidity (such as aluminum alloy) needs to design a smaller sprue cup, while molten metal with poor fluidity (such as cast iron) needs a larger sprue cup.

Temperature: High-temperature molten metal requires higher fire resistance of the sprue cup, and the influence of thermal expansion on the size needs to be considered.

Chemical composition: The chemical composition of molten metal may affect its reactivity with the sprue cup material. For example, some alloys may corrode certain refractories.

III. Pouring process parameters

Pouring speed: Pouring speed will affect the flow state of molten metal. Faster pouring speed may lead to splashing and oxidation of molten metal, so it is necessary to design buffer structure.

Pouring time: the pouring time should be adjusted according to the size and shape of the casting to ensure that the molten metal can completely fill the mold.

Pouring temperature: Too high or too low pouring temperature will affect the quality of castings, so the design of sprue cup needs to consider the uniformity of temperature.

IV. Structural design of sprue cup

Buffer structure: The design of buffer structure can reduce the impact of molten metal and avoid splashing and damage to the mold.

Filter structure: A filter screen or ceramic filter sheet is arranged in the sprue cup, which can remove impurities in molten metal and improve the purity of castings.

Shunt structure: for complex castings, the design of shunt structure can ensure the uniform distribution of molten metal to all parts.

Exhaust structure: the design of exhaust passage can avoid the blowhole when molten metal enters and improve the quality of castings.

V. Material selection

Fire resistance: The fire resistance of the material must be higher than the pouring temperature of molten metal to prevent the sprue cup from softening or melting at high temperature.

Thermal shock resistance: materials need to be able to withstand rapid temperature changes and avoid cracking or peeling due to thermal stress.

Slag corrosion resistance: the material should be able to resist the corrosion of impurities in molten metal and prolong the service life of the sprue cup.

Mechanical strength: the material needs to have enough strength to withstand the impact and erosion of molten metal.

VI. Size and shape

Capacity: The capacity of the sprue cup should be designed according to the size of the casting and the pouring process to ensure that molten metal can completely fill the mold.

Shape: The shape of the sprue cup should be conducive to the smooth flow of molten metal and avoid vortex and splash. Common shapes include cylinder, cone, etc.

Dimensional accuracy: The size of the sprue cup should be strictly controlled to ensure the docking accuracy with the mold.

VII. Convenience and safety of operation

Operating height: the height of the pouring cup should be convenient for the operator to carry out pouring operation, and at the same time, the molten metal should not splash to the operator.

Installation position: The sprue cup should be installed in a proper position of the mold to facilitate the inflow of molten metal and the operation of operators.

Safety: In the design, it is necessary to consider the safety issues such as preventing molten metal from overflowing and splashing, so as to ensure the safety of operators.

VIII. Cost and economy

Material cost: on the premise of meeting the performance requirements, try to choose materials with lower cost.

Processing cost: The complexity and cost of processing should be considered in the design, so as to avoid excessive processing cost caused by too complicated structure.

Service life: A properly designed sprue cup can prolong the service life and reduce the replacement frequency, thus reducing the production cost.

IX. Environment and sustainability

Environmentally friendly materials: Choose environmentally friendly materials to reduce the impact on the environment.

Recyclable: The design considers the recyclability of the sprue cup to reduce the waste of resources.

X. Summary

The design of sprue cup needs to comprehensively consider the casting structure, characteristics of molten metal, pouring process parameters, material selection, size and shape, convenience and safety of operation, cost and economy, environment and sustainability. Through reasonable design, the quality and production efficiency of castings can be improved, while the production cost and environmental impact can be reduced.