High-pressure Die Casting and Low-pressure Die Casting are two different casting processes, and they are significantly different in many aspects.
First of all, the essence of high-pressure casting is to fill the die-casting mold (die-casting mold) cavity with liquid or semi-liquid metal at a high speed under high pressure, and form and solidify under pressure to obtain a casting. The commonly used injection pressure is very high, and the filling speed is also very fast, usually completed within 0.01~0.2 seconds. This casting method is suitable for large-scale, batch production because of its high production efficiency, high product precision and good surface finish. In addition, high-pressure casting can use a variety of materials, showing strong adaptability.
In contrast, the principle of low-pressure casting is to pass dry compressed air or inert gas into a sealed crucible, and by applying a certain low pressure, the metal liquid can fully fill the cavity of the mold and maintain a certain pressure. After the metal solidifies, by reducing the pressure, the mold can be smoothly demoulded to obtain the desired casting. The advantages of low-pressure casting are that the internal structure of the casting is dense, there are no pores, the mechanical properties are good, and the surface finish is high, without the need for secondary processing. In addition, it can also realize automated production and improve production efficiency. However, the equipment cost of low-pressure casting is higher, the operation requirements are stricter, the requirements for molds are also higher, and the production cycle is longer.
To sum up, there are obvious differences between high-pressure casting and low-pressure casting in terms of principles, application fields, production efficiency, product accuracy, and cost. The choice of casting method depends primarily on specific product requirements, production scale, and economic conditions.