Die Casting Is A Metal Casting Process
Die casting is a metal casting process, which is characterized by the use of mold cavity to melt the metal to exert high pressure. Molds are usually machined with higher strength alloys, and this process is somewhat similar to injection molding. Most die cast castings are iron free, such as zinc, copper, aluminum, magnesium, lead, tin and lead-tin alloys and their alloys. Depending on the type of die casting, a cold chamber die casting machine or a hot chamber die casting machine is required.
Casting equipment and molds are expensive, so die casting processes are generally only used to mass-produce large quantities of products. It is relatively easy to manufacture die-cast parts, which typically requires only four major steps, with a very low individual cost increment. Die casting is particularly suitable for the manufacture of large quantities of small and medium-sized castings, so die casting is the most widely used in a variety of casting processes. Compared with other casting technology, die-casting surface is more smooth, with a higher size consistency.
On the basis of the traditional die-casting process, several improved processes have been developed, including non-porous die-casting processes that reduce the porosity of cast defects. Mainly used for processing zinc, can reduce the waste to increase the yield of direct injection process.
The advantages of die casting include the casting with excellent dimensional accuracy. Usually this depends on the casting material, the typical value is the initial 2.5 cm size when the error is 0.1 mm, and the error is increased by 0.002 mm for each additional 1 cm. Compared to other casting processes, its cast surface is smooth, rounded radius of about 1-2.5 microns. Molds with a wall thickness of about 0.75 mm can be made with respect to sandbox or permanent die casting. It can directly cast the internal structure, such as silk sets, heating elements, high-strength bearing surface. Other advantages include the ability to reduce or avoid secondary machining, production speed, casting tensile strength of up to 415 MPa, can cast high-mobility metal.
The biggest drawback of die casting is the high cost. Casting equipment and molds, mold-related components are very expensive relative to other casting methods. So the manufacture of die-casting when the production of a large number of products is more economical. Other shortcomings include: This process is only applicable to the higher mobility of metal, and casting quality must be between 30 grams and 10 kg. In the usual die casting, the final cast of a batch of castings will always have pores. And therefore can not carry out any heat treatment or welding, because the gas within the gap will be under the action of heat expansion, resulting in internal micro-defects and surface stripping.