Die Casting Parts Basic Characteristic
Pressure casting is characterized by high speed and high pressure, Die Casting Parts which is also the basic characteristic of pressure casting which is different from other casting processes. The filling process involves mechanical, thermal and hydrodynamic phenomena. Pressure, Die Casting Parts injection speed, metal temperature changes make this The process becomes quite complex.Pressure filling process is theoretically divided into three stages: the first stage, the metal liquid into the cavity at high speed, the impact of the gate opposite the wall, and along the wall in the other direction of the rapid expansion of the formation of the shell ; Die Casting Parts The second stage, followed by the metal into the cavity to continue to fill the cavity; the third stage, the cavity of the molten metal under the action of the pressurized pressurization quickly compaction cooling. Die Casting Parts Metal flow casting defects are mostly produced in this process It can be seen that the factors that affect the quality of the die cast are multifaceted, but the most important is the filling conditions (porosity, dimensional accuracy and surface quality in the casting). The variable factors in the filling process are complex and diverse Which is divided into dynamic and static two aspects. Static including die casting machine performance, casting structure, mold structure,Die Casting Parts mold materials, release agent, energy storage pressure, , Limit switch, and the viscosity of the hydraulic oil temperature of the molten metal and the like; metal comprising an amount of the dynamic pressure chamber, a punch suffered running resistance, Die Casting Parts the mold temperature curve and a negative pressure at the vacuum casting.
For a quality of a die cast, the casting system occupies a very important position and is a decisive factor. As a system, there are feed and outlet, slagging links, consisting of many elements, the purpose is to make the alloy liquid in the proper flow Into the cavity filling at the same time to maximize the discharge of gas within the system.The so-called appropriate flow, that is, does not produce liquid flow collision, Die Casting Parts volume gas, air, smooth speed.As the cast has its own characteristics, although there are computers Simulation analysis software can help to see some kind of results, but for bad results, or rely on people according to practice and experience to change the program.General entrance direction and distribution of the exhaust has an important impact on the direction of the entrance must be as much as possible To ensure that the liquid flow along the wall filling, Die Casting Parts favorable exhaust, the distribution of which way to consider the distribution can be more orderly filling, do not hold their breath .In addition, according to the metal liquid flow analysis, combined with overflow slot settings, Die Casting Parts in the appropriate part of the row Gas tank, the cavity of the gas discharge. With the exhaust slot, set up overflow slot, not only the gas and cold metal can be discharged from the cavity, Die Casting Parts but also to control the filling of metal State, reduce or prevent the formation of vortices.
Shock wave. The pressure shock wave generated at the moment when the filling of the alloy liquid is completed and the movement of the head is likely to have an adverse effect on the quality and cost of the casting, the life of the mold, the production efficiency, Die Casting Parts the production management and the safety of the operation. Eliminate the shock wave. At present, the following methods can be used to reduce the shock wave.