Compared with other metal forming processes, the Die-casting features are:
(1) productivity is extremely high
The production process is easy to realize the mechanization and automation. General cold chamber Die casting machine every eight hours can be 600 to 700 times the die-casting, hot-pressing die-casting machine every eight hours to die-casting 3 000 to 7 000 times. And a die-casting mold cavity often more than one, so that the number of die-casting production will also exponentially increased.
(2) High dimensional accuracy of the casting
The size of stability, consistency, and less processing allowance and a good assembly. Die-casting of the accuracy of up to IT11 ~ IT13 level, and sometimes up to IT9 level. Surface roughness values are generally Ra0.8 ~ 3.2, the lowest up to Ra0.4. General die castings only a few parts of the size of machining, and some parts without even mechanical processing can be directly assembled to use. This high utilization of materials, up to 60% to 80%, a rough utilization rate of 90%.
(3) Casting dense organization, with high strength and hardness.
As the metal liquid is solidified under pressure, and because of high-speed filling, the cooling rate is extremely fast, so that the casting surface to generate a layer of the cold hard layer (about 0.3 ~ 0.8mm), the layer of metal grain is small, dense organization. Therefore, high strength and hardness of die-casting, solid wear-resistant. When the die wall thickness is appropriate and uniform, its strength is higher.
(4) It can be a complex casting shape
Clear-cut thin-walled deep cavity casting, because of the liquid metal under high pressure to maintain high mobility.
The minimum wall thickness of zinc alloy die-casting parts can reach 0.3 mm, aluminum alloy is about 0.5 mm. The minimum casting diameter is 0.7 mm and the minimum pitch of the castable thread is 0.75 mm.
Die-casting assembly features
(1) The inlay casting method eliminates the assembly process. Simplifies the manufacturing process. Parts of other materials such as magnets, brass sleeves
and insulating materials can be embedded directly into specific parts of the die casting to meet specific requirements, eliminating the need for assembly processes and simplifying the manufacturing process.
(2) Casting the existence of porosity, but generally, still, meet the requirements. As the filling of liquid metal is extremely fast, it is difficult to completely remove the gas entrained in the cavity during filling, which results in the presence of pores and oxidized inclusions in the die castings, thereby reducing the quality of the die castings. Therefore, the general die casting can not be heat-treated, and should not work at high temperatures. Similarly, do not want to mechanical processing, so as not to expose the pores under the casting surface.
(4) The size of the die-casting die-casting machine by clamping force and size constraints mold, so the production of large-scale die casting production is limited. At present, the large-scale die-casting machine has been developed, large parts die casting problem is gradually being resolved.
(5) The die-casting process is only suitable for mass production. As the high price of the die-casting machine, die casting mold manufacturing costs are high, long hours, maintenance costs are high, so the total cost of production, not small batch production.