cold chamber die casting machine
pressure die casting machine refers to the application of about 2 times of high pressure [500-1500 kg / cm] to the final pressure of document speed injection in a very short time {MS setting conditions} after the injection. Therefore, it does not refer to the pressure value above, but to what device can effectively increase the pressure to higher than the high-speed final pressure to achieve the effect of pressurization. The final casting pressure refers to the pressure after about 0.3 seconds after the completion of injection, whether pressurized or not. Generally, the purpose of effective pressurization to improve the final casting pressure is to forcibly squeeze the liquid metal from the solidification shrinkage part that is rapidly solidified after filling the forming part, so as to prevent the so-called depression. At the same time, the residual pores and pin holes that are not removed from the forming part are compressed with high pressure to make them smaller.
In order to achieve these two purposes, the higher the final pressure, the better the effect, but the higher the final pressure, the smaller the casting projection area. Therefore, larger casting machines and stronger molds are needed, which brings economic problems, so the range of 500-800 kg / cm is enough.In order to make full use of the pressurization effect, the time to rise to the final pressure after high-speed filling, that is, the pressurization rise time, is very important. Theoretically, pressurization should be maintained from the beginning of solidification to the end of solidification. If flash splashing occurs too early, and if the gate solidifies too late, it is impossible to replenish and pressurize the liquid metal at the forming part. In practical production, the pressurization rise time of medium pressure caster is generally set at 10-30ms.
The pressurization device varies with the die casting machine manufacturer. Toshiba and Toyo machines only need to read the pressure gauge of the injection cylinder to see the difference between the pressure when the pressurization is effective and invalid. However, when the pressurization of Yubu machine is invalid, the pressure on the hydraulic oil supply side is the same as that on the discharge side. The pressure on the discharge side is called back pressure. When the back pressure is 0, it is 100% pressurized, and the pressure on the discharge side is above 0, When the supply side is below the pressure, it is the effective percentage of pressurization. The final pressure can be seen from the operating manual of the machine.
alloy die casting machine
Allowable pressure value kg / C ㎡ = clamping force kg × 0 9／casting area C ㎡
When the calculated value is less than the final pressure calculated in the machine operation manual, the machine shall be adjusted to the final pressure below the calculated value. Conversely, the calculated value is greater than the final pressure calculated in the machine operation manual, but there is flash ejection. Generally, there is a problem with the mold. Confirm the mold clamping again.
