Vacuum system in aluminum alloy die casting of application
Pressure casting is characterized by high speed and high pressure. In the process of die casting, gas is inevitably involved in the liquid metal, so die casting is not suitable for improving mechanical properties through heat treatment. The high vacuum die-casting method is an effective method to reduce the porosity and improve the mechanical properties of die castings. In this paper, by considering the actual situation, developed a set of vacuum system in aluminum alloy die casting practical application of the solution, the following small series to give you a detailed introduction of the characteristics of the vacuum system.
Things always have two sides. Although die-casting technology has so many advantages, it also inevitably has limitations:
1. Air holes often exist in die castings;
2. Not suitable for small batch production;
3. Die casting size is limited;
4. The types of die-casting alloys are limited.
Many customers know that aluminum alloy die-casting products are mainly used in electronics, automobiles, motors, household appliances and some communication industries, and some high performance, high precision, high toughness aluminum alloy products are also used in large aircraft, ships and other industries with high requirements. The main use is still in the parts of some instruments. Because of its importance, therefore, to find a more suitable method of die-casting.
In view of the problems caused by the ordinary die-casting process, dongguan punok vacuum technology co., ltd. recommended its vacuum system products.
The vacuum die-casting method also has the general vacuum die-casting process and the high vacuum die-casting process, small series focus on the introduction of the latter.
There are actually three types of vacuum systems:
1. Low vacuum system
2. Medium-vacuum system
Roots pump by the main pump series mechanical pump system;
A system consisting of a series of mechanical pumps for the main pump of an oil booster pump;
A system consisting of roots pump in series with a small roots pump and a mechanical pump in series.
3. High vacuum system
By the diffusion pump main pump series roots pump, and then series mechanical pump system;
A vacuum system composed of a diffusion pump and a mechanical pump in series;
A vacuum system consisting of a diffusion pump in series with the main pump and a mechanical pump in series.
High vacuum die-casting process refers to the special die-casting process with the vacuum degree above 91Kpa. Due to the high vacuum degree in the mold cavity during injection, the metal liquid is involved in less gas, and the gas content of the casting is only 1~3ml/100g. Therefore, high vacuum die-casting can be processed or welded.
The vacuum system has the following characteristics:
1. Low noise and vibration.
2. Air cooling, convenient and easy.
3. Good operation in high temperature environment.
4. Keep good pumping speed under low vacuum pressure.
5. Built-in filter center and filter can achieve high filtering effect.
6. Built-in one-way valve to prevent reverse flow of vacuum oil.
7. Simple structure, small volume, save space.
8. Multi-function concept, which can be adapted to the special configuration of customers.
9. Easy to maintain.
The vacuum system for aluminum alloy die-casting has the advantages of adjustable transmission ratio, flexible, fast and reliable piston closure, avoiding the defects of poor flexibility and low reliability in the existing design. The vacuum system has strong air extraction capacity, which can make the vacuum degree in the mold cavity reach 91KPa within 1s, meeting the requirements of high vacuum die-casting process. In view of the practical application of vacuum system in aluminum alloy die casting, the comparison between ordinary die casting and vacuum die casting is made.