压力铸造,是将金属液高速压入金属型腔,并在压力下充型,凝固后开模取件的铸造方法,主要用来大量生产铝合金精密铸件,例如,在汽车、摩托车发动机上使用的铝合零件。因近年来这类零件的结构日益复杂,对机械加工后的气密性要求也不断提高,使常规的压铸技术难以胜任。日本一家公司抓住“脱气成型”这一关键,分析了型腔内空气压力和金属液动态特性,研制出一种将排气阀门与真空箱组合使用的压铸新技术。其基本结构以及工艺过程介绍如下: 排气阀装在金属模结合面上(见图1),型腔内气体经排气孔,由电磁阀排放到真空箱。阀门由拉力弹簧拉住,其阶梯部分受到钢球的限制,故不会被气流所推动,钢球的压紧力由可调螺钉调节。图2所示为金属液以15～40m/s的速度径直涌向阀门的状况。因金属液质量比气空气大得多,所以呈直线推进而不拐向两旁的排气孔。图3所示,高速流动的金属液冲 Pressure casting, is a high-speed liquid metal into the metal cavity, and under the charge filling, solidification after the opening of the mold parts of the casting method, mainly used for mass production of aluminum alloy precision castings, for example, in the car, motorcycle engine Used aluminum parts. Due to the increasingly complex structure of such parts in recent years, the requirements for the airtightness after machining have also been continuously raised, making conventional die-casting techniques difficult to perform. A Japanese company grasps the key of “degassing forming”, analyzes the air pressure in the cavity and the dynamic characteristics of the molten metal, and develops a new die-casting technology which combines the exhaust valve with the vacuum box. The basic structure and process are described as follows: Exhaust valve mounted on the mold surface (see Figure 1), the cavity of the gas through the exhaust hole, the solenoid valve discharge to the vacuum box. Valve pulled by the tension spring, the ladder part of the ball by the restrictions, it will not be driven by the airflow, ball pressure by the adjustable screw adjustment. Figure 2 shows the metal liquid to 15 ~ 40m / s speed straight to the valve condition. Due to the mass of liquid metal is much larger than the air, so straight forward without turning to the exhaust holes on both sides. Figure 3 shows the high-speed flow of molten metal