Under the premise of satisfying the function of the product, it is reasonable to design pressure die casting, simplify mold structure, reduce cost, defects and improve the quality of casting parts. Since the injection molding process is derived from the casting process, the die casting design guidelines are very similar to the plastic parts design guidelines in some aspects. Next are some of the designs of it.
Here is the content:
Rounded corners
Release slope
Roughness
Flowability
Rounded corners
We must not ignore the role of these unspecified rounded corners when opening the mold, and must not make clear corners or too small rounded corners. Die casting rounded corners can make the metal liquid fill smoothly, make the cavity gas sequence discharge, and can reduce the stress concentration, prolong the service life of the mold. (Castings are also less likely to crack in the place or due to poor filling and various defects). For example, there are more clear corners on the standard oil pan die, relatively speaking, the current Brother oil pan die is the best open, and there are more heavy machine oil pans.
Release slope
The side concavity caused by a human is strictly forbidden in the direction of mold release (often the pressure die casting is stuck in the mold when the mold is tested, and when it is handled in an incorrect way, such as drilling, hard chiseling, etc. to make local concavity).
Roughness
Molding parts and the pouring system should be carefully polished as required and should be polished in the direction of die casting mold release. Since the whole process of metal liquid entering the pouring system from the pressure chamber and filling the cavity is only 0.01-0.2 seconds. To reduce the resistance of metal liquid flow and make the pressure loss as little as possible, all need to flow through the surface with a high degree of finish. At the same time, the pouring system part of the heat and erosion by the worse conditions, the poorer the finish is the mold the more easily damaged. When processing, the mold should try to leave a margin for repair, do the upper limit of the size, and avoid welding.
Flowability
Fluidity refers to the ability of the alloy liquid to fill the mold. The size of mobility determines whether the alloy can cast complex die castings. In aluminum alloy, the eutectic alloy has the best mobility. Many factors are affecting the fluidity, mainly the composition, temperature, and the presence of metal oxides, metal compounds, and other contaminants in the alloy liquid-solid phase particles. But the fundamental external factors are the pouring temperature and pouring pressure (commonly known as the pouring pressure head) high or low.
In actual production, the alloy has been determined, in addition to strengthening the melting process (refining and slag removal), but also must improve the die casting process (sand mold permeability, metal mold exhaust, and temperature). And in the premise of not affecting the quality of the die casting to improve the pouring temperature to ensure the fluidity of the alloy.
Once the die-casting machine in the design of improper choice, will directly affect the performance of the die-casting machine, production costs will climb, but also can not be expected to recover costs, resulting in heavy losses of enterprises. Therefore, the above factors must be weighed in the decision.
