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Description of the characteristics and differences of various casting (2017-03-05)
1 casting can be divided into gravity casting and pressure casting according to the pouring process of metal liquid. Gravity casting is the process of injecting molten metal into the mold under the action of gravity. The generalized gravity casting include sand casting, metal mold casting, investment casting, mud casting; metal type casting refers to narrow gravity casting. Pressure casting is the process of pouring molten metal into the mold under the action of other external forces (without gravity). Generalized pressure casting die casting machine including pressure casting and vacuum casting, low pressure casting, centrifugal casting; metal pressure casting narrow die casting machine casting, referred to as die casting. Xudong precision casting factory engaged in sand mold and metal mold gravity casting. The casting process is the most commonly used and the lowest price in non-ferrous metal casting.
2 sand casting is a sand as the main materials, make the traditional mould casting process. General use of the gravity casting sand, with special requirements can be used when low pressure casting, centrifugal casting process. Sand casting wide adaptability, large and small, simple, complex parts, single and mass are used. Sand casting mould, formerly made of wood, as wood. Xudong precision casting factory in order to change the block deformation and easy to damage other ills, in addition to sand casting production of single, all to the higher dimensional accuracy, and long service life Aluminum Alloy mold or resin mold. Although the price has improved, but still much cheaper than the metal mold casting, in small quantities and large production, the price advantage is particularly prominent. In addition, the sand ratio of metal refractory degree is higher, and such as copper alloy and ferrous metal of high melting point materials also adopt this technology. However, sand casting also has some shortcomings: because each sand casting gating only once, get after casting mould is damaged, you must re shape, so the sand casting production efficiency is relatively low; and because the overall properties of sand is soft and porous, so the sand casting casting dimension precision is low, the surface is rough. However, the accumulation of years of Xudong precision casting factory technology, has greatly improved the surface condition of sand castings, the blasting effect after the metal mold casting rival.
3 metal mold casting is a modern technology for making hollow casting mold with heat-resistant alloy steel. The metal type can be either gravity casting or pressure casting. Metal mold mold can be repeated many times, each casting a metal liquid, it will be a casting, a long life, high production efficiency. The metal mould casting not only good dimensional accuracy, surface finish, and in the same pouring liquid metal under the condition of the casting strength higher than the sand, not easy to damage. Therefore, in the production of large quantities of non-ferrous metals in the medium and small castings, as long as the melting point of the casting material is not too high, generally preferred metal casting. However, metal casting also has some shortcomings: because of heat resistant alloy steel and make a hollow cavity on the top of the processing is relatively expensive, so the metal mold is expensive, but the overall and casting mould are much cheaper than the cost. For small batch production, the cost of each product is allocated to the mold is obviously too high, generally not easy to accept. Also because of the metal mold by the size of the mold material and cavity processing equipment, casting equipment, the ability to limit, so the special casting is also powerless. Therefore, in small batch and large production, the use of metal casting. In addition, although the metal mould adopts heat resistant alloy steel, but the heat capacity is still limited, generally used for casting Aluminum Alloy, zinc alloy, magnesium alloy, copper alloy casting has been used less, and less for black metal casting. Metal Xudong precision casting factory mold is all designed and manufactured, which can timely provide quality cheap, suitable for the customer mold.
4 die casting is a die casting machine on the metal pressure casting, is currently the most efficient casting process. Die casting machine is divided into hot chamber die casting machine and cold chamber die casting machine two categories. Hot chamber die-casting machine a high degree of automation, less material consumption, the production efficiency is higher than the cold chamber die casting machine, but restricted by mechanical heat capacity, at present can only be used in casting production of zinc alloy, magnesium alloy and other low melting point materials. Today's widely used aluminum alloy die castings, due to the high melting point, can only be produced in cold chamber die casting machine. The main characteristics of die casting is the molten metal in the cavity filling under high pressure and high speed, and under high pressure forming, solidification, deficiency of die casting is: because the liquid metal in the process of high pressure, high speed filling cavity, inevitably the cavity in the air wrapped in the castings, the formation of blowhole so Aluminum Alloy die casting for heat treatment, zinc alloy die casting surface spray (but not painting). Otherwise, when the inner hole of the casting is heated, the heat distortion of the casting can be caused by the thermal expansion. In addition, die casting mechanical machining allowance should be made smaller, generally about 0.5mm, can reduce casting weight, reduce cutting amount to reduce the cost, but also can avoid the penetration of surface dense layer, exposing the blowhole, cause the scrap.