The characteristics and differences of various castings

1. Casting can also be divided into gravity casting and pressure casting according to the pouring process of liquid metal. Gravity casting refers to the metal liquid under the action of earth gravity into the casting process, also known as casting. The generalized gravity casting includes sand casting, metal casting, investment casting, mud casting, etc. Narrow gravity casting refers to metal mold casting. Pressure casting is a process in which liquid metal is injected into the mold under the action of other external forces (excluding gravity). Pressure casting in a broad sense includes pressure casting and vacuum casting, low pressure casting, centrifugal casting, etc. Narrow sense of pressure casting refers to the metal mold pressure casting machine, referred to as die casting. Xudong Precision Casting Factory has long been engaged in gravity casting of sand and metal molds. These casting processes are the most commonly used in non-ferrous metal casting, but also the lowest relative price.

2. Sand casting is a traditional casting process that uses sand as the main molding material. The sand mold is generally cast by gravity, and low pressure casting and centrifugal casting can also be used when there are special requirements. Sand casting has a wide range of adaptability, small, large, simple, complex, single, large quantities can be used. Sand casting mold, used to use wood production, commonly known as wood mold. Xudong Precision Casting Factory has changed all aluminum alloy moulds or resin moulds with high dimensional accuracy and long service life, except for the sand moulds produced in a single piece, in order to change the defects of easy deformation and easy damage of wood moulds. Although the price has been improved, but it is still much cheaper than the metal mold casting mold, in small batch and large production, the price advantage is particularly prominent. In addition, sand is more refractory than metal, so materials with higher melting points such as copper alloys and ferrous metals are also used in this process. However, sand casting also has some shortcomings: because each sand casting can only be cast once, the casting is damaged after the casting, must be re-shaped, so the production efficiency of sand casting is low; Because the overall nature of sand is soft and porous, the dimensional accuracy of sand casting is low and the surface is rough. However, XUDong Precision Castings has greatly improved the surface condition of sand castings, and the effect of shot blasting is comparable to that of metal castings.

3. Metal mold casting is a modern process of making hollow mold for casting with heat-resistant alloy steel. The metal mold can be cast by gravity or pressure. The casting mold of the metal type can be used repeatedly. Every time the gold liquid is poured, the casting is obtained. The life is very long and the production efficiency is very high. The metal casting is not only good dimensional accuracy, smooth surface, and in the case of pouring the same liquid metal, the casting strength is higher than that of the sand mold, and it is not easy to damage. Therefore, in the mass production of medium and small castings of non-ferrous metals, as long as the melting point of the casting material is not high, metal mold casting is generally preferred. However, metal mold casting also has some disadvantages: because the heat resistant alloy steel and the processing of hollow cavities on it are more expensive, so the metal mold cost is not cheap, but overall and die casting mold cost is much cheaper. For small batch production, the cost of molds per product is obviously too high and generally not acceptable. And because the metal mold is limited by the size of the mold material and the capacity of the cavity processing equipment and casting equipment, it is also unable to do anything about the especially large castings. As a result, metal mold casting is rarely used in small batch and large production. In addition, although the metal mold uses heat-resistant alloy steel, its heat-resistant capacity is still limited. It is generally used in the casting of aluminum alloy, zinc alloy and magnesium alloy, and has been less used in copper alloy casting, and even less used in ferrous metal casting. Xudong PRECISION CASTING FACTORY DESIGNS AND MANUFACTURES ALL THE metal MOULDS BY OURSELVES, SO WE CAN PROVIDE CUSTOMERS WITH high-quality MOULDS WITH LOW price and APPLICABILITY in a more timely manner.

4. Die casting is a metal mold pressure casting on the die casting machine, which is the most efficient casting process at present. Die casting machines are divided into hot chamber die casting machines and cold chamber die casting machines. Hot chamber die casting machine has a high degree of automation, less material loss, and higher production efficiency than cold chamber die casting machine. However, limited by the heat resistance of parts, it can only be used for casting of zinc alloy, magnesium alloy and other low melting point materials at present. Aluminum alloy die castings, which are widely used today, can only be produced in cold chamber die casting machines because of their high melting points. The main characteristics of die casting are that liquid metal fills the cavity under high pressure and high speed, and forms and solidifies under high pressure. The shortcomings of die casting are: Because the liquid metal in the process of filling the cavity at high pressure and high speed, inevitably the air in the cavity is wrapped in the casting, forming subcutaneous pores, so aluminum alloy die casting is not suitable for heat treatment, zinc alloy die casting is not suitable for surface spray (but can be spray paint). Otherwise, the internal air hole of the casting will be thermally expanded and cause the casting to deform or bubble when heated by the above treatment. In addition, the mechanical cutting allowance of die casting should also be smaller, generally about 0.5mm, which can not only reduce the weight of casting, reduce the cutting amount to reduce the cost, but also avoid penetrating the surface dense layer, exposing the subcutaneous pores, resulting in the scrap of the workpiece.