The basic way to reduce the die casting pores
Reduce the die-casting pieces of stomata mainly from melting, mold, die-casting parameters, the four aspects of the parting agent to take measures. Among them, the most important factors of the molds, the most active the fullness of the pressure chamber die-casting parameters, the conversion of the speed of the injection point is easily overlooked.
For the quality of a die casting, gating system is the decisive factor. As a system, the feed outlet, the slag areas by many elements of composition, the purpose is to enable the molten alloy into the cavity filled with the appropriate flow pattern to maximize the exhaust system, gas. The so-called appropriate flow pattern is not generated flow collision volume air sac gas, steady speed. Otherwise, the row overflow system no matter how good, gas row not. Die castings have their own characteristics, practical, empirical strong, although there are computer
Simulation software helps us to see some results, but negative results, or rely on people to change the program. In the example shown in Figure 1, we understand the important influence of the direction of the entrance gate in these programs and distribution of exhaust. Entrance direction, we must try to ensure that the flow along the wall type of fill, enabling exhaust distribution take into account what kind of distribution can be more orderly fill, do not hold your breath.
Casting process parameters
The die casting process parameters and the porosity affect the larger two. The entrance to the direction of the runner, distribution, whether orderly filled smooth exhaust is very important, the first pressure the shoot length (may be called the exhaust stroke) and speed. Fast injection early (meaning before the melt into the runner), the pressure chamber, the cavity exhaust is inadequate, resulting in the volume gas; late will have to cold shut, due to cast. First injection was set to discharge pressure chamber and the cavity gas, can achieve this effect also depends on a critical speed, the speed of the pressure chamber filled with not a volume rate of gas production should meet it. The pressure chamber filled with the degree of stomatal defects on the casting is very significant. Full of high and slow shot is not easy, the volume gas pressure chamber above the air into the cavity of the gas will be less, so the condition does not affect the fill rate, the diameter of the pressure chamber should try to take a small. Short pressure chamber is the product of such a request, both to ensure full without reducing filling