1. There are many processes to make metal materials into desired products, such as casting, forging, extrusion, rolling, drawing, stamping, cutting, powder metallurgy and so on. Among them, casting is the most basic, the most commonly used and the most extensive process.
2. Molten metal is injected into a hollow mold made of a heat-resistant material, and a product of the desired shape is condensed. The resulting product is the casting.
3. Casting can be divided into black metal casting (including cast iron, cast steel) and non-ferrous metal casting (including aluminum alloy, copper alloy, zinc alloy, magnesium alloy, etc.) according to the material of casting. Nonferrous Precision Casting Plant specializes in nonferrous metal casting, with emphasis on aluminum alloy and zinc alloy casting.
4. Casting can be divided into sand casting and metal casting according to the casting material. Precision casting plants are proficient in these two casting processes, and design and manufacture these two kinds of casting molds themselves.
5. Casting can also be divided into gravity casting and pressure casting according to the pouring process of metal liquid. Gravity casting refers to the process of metal liquid injection into the mold under the action of earth gravity, also known as casting. Generalized gravity casting includes sand casting, metal casting, investment casting, lost casting, mud casting, etc. Narrow gravity casting refers specifically to metal mold casting. Pressure casting refers to the process in which liquid metal is injected into the mold under the action of other external forces (excluding gravity). The generalized pressure casting 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. Precision Casting plant has been engaged in gravity casting of sand and metal molds for a long time. These casting processes are currently the most commonly used in non-ferrous metal casting, but also the lowest relative price.
6. Sand mold casting is a kind of traditional casting technology which uses sand as the main molding material to make the mold. Sand mold is generally cast by gravity, and low pressure casting, centrifugal casting and other processes can also be used if there are special requirements. Sand casting has a wide range of adaptability, small pieces, large pieces, simple pieces, complex pieces, single pieces, large quantities can be used. Sand mold casting mold, used to be made of wood, commonly known as wood mold. Xudong Precision Casting Factory has changed all the aluminum alloy molds or resin molds with high dimensional accuracy and long service life except the sand molds produced by a single piece in order to change the defects of wood molds which are easy to be deformed and damaged. Although the price has improved, but it is still much cheaper than the mold used in metal casting, in small batch and large production, the price advantage is particularly prominent. In addition, sand types have higher refractoriness than metal types, 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, after the casting is damaged, it must be rebuilt, so the production efficiency of sand casting is low; And because the overall property of sand is soft and porous, the dimensional accuracy of sand casting is low, and the surface is rough. However, many years of technical accumulation in precision casting plants have greatly improved the surface condition of sand castings, and the effect of shot blasting can be comparable to that of metal castings.
7. Metal mold casting is a modern technology of making hollow mold with heat-resistant alloy steel. Metal forms can be cast by gravity or pressure casting. The metal mold can be used repeatedly. Every time the metal liquid is poured, the casting is obtained. The service life is very long and the production efficiency is very high. Metal castings not only have good dimensional accuracy, smooth surface, but also in the case of pouring the same metal liquid, the strength of the casting is higher than that of the sand type, more not easy to damage. Therefore, in the mass production of non-ferrous metal castings, as long as the melting point of the casting material is not high, metal casting is generally preferred. However, metal casting has some disadvantages: because heat-resistant alloy steel and the hollow cavity in it are expensive to process, the metal mold is expensive, but the overall cost is much cheaper than the die casting mold. For small batch production, the cost of the mold shared on each product is obviously too high, 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 the casting equipment, it is powerless to do anything about the particularly large casting. Therefore, in small batch and large production, metal mold casting is rarely used. In addition, although the metal mold uses heat-resistant alloy steel, its heat-resistant ability is still limited. It is generally used for the casting of aluminum alloy [1], zinc alloy and magnesium alloy, which has been less applied in copper alloy casting, and even less for black metal casting.
8. Die casting is the metal molding pressure carried out on the die casting machine. It is the casting process with the highest production efficiency. Die casting machine is divided into hot chamber die casting machine and cold chamber die casting machine two types. Hot chamber die casting machine has high automation degree, less material loss and higher production efficiency than cold chamber die casting machine. However, limited by the heat resistance of the parts, it can only be used for the casting production of zinc alloy, magnesium alloy and other low melting point materials at present. Aluminum alloy die casting, which is widely used today, can only be produced on cold chamber die casting machines because of its high melting point. The main characteristic of die casting is that the metal liquid fills the cavity under high pressure and high speed, and forms and solidifies under high pressure. The shortcomings of die casting are as follows: Because in the process of filling the cavity with metal liquid at high pressure and high speed, the air in the cavity is inevitably wrapped in the inside of the casting, forming subskin pores, so the aluminum alloy die casting is not suitable for heat treatment, and the zinc alloy die casting is not suitable for surface spraying (but can be painted). Otherwise, the internal pores in the casting will be heated by heat expansion resulting in casting deformation or bubbling. In addition, the mechanical cutting allowance of die casting should also be smaller, generally about 0.5mm, which can reduce the weight of the casting, reduce the cutting amount to reduce the cost, and avoid penetrating the dense layer on the surface, exposing the subcutaneous pores, resulting in the scrap of the workpiece.