Pressure casting, which is also called“die casting”, is a casting method by pouring alloy liquid into a pressure chamber to fill the steel cavity of the mold at high speed ,through which die casting part can be formed under pressure.Compared with other casting methods,the main features of die castings are high pressure and high speed.
The metal liquid is filled into the cavity under pressure ,and then it get crystallized and solidified under higher pressure.
The metal liquid is filled into the cavity at a high speed and extremely short time,about 0.01-0.2 seconds (depends on the size of the casting)to fill the cavity.Die-casting is a precision casting method.The die casting parts produced by die-casting are in high accuracy.
In most cases,die-casting parts can be directly used for assembly without extra lathe machining.Most of the small parts,from camera parts,typewriter parts,electronics and decorations,to complex parts of vehicles such as automobiles,locomotives,and airplanes,all can be manufactured by die casting.
Advantages of die casting:
Excellent dimensional accuracy, but depends on the casting material. Compared with other casting processes, its casting surface is smooth. In addition, internal structures such as wire sleeves, heating elements, and high-strength supporting surfaces can be cast directly. Some other advantages include that it can reduce or avoid additional machining, faster production speed and higher tensile strength.
Disadvantages of die casting:
The biggest disadvantage of die casting is the high cost.Casting equipment and molds,mold-related components are expensive compared to other casting methods.Therefore,it is more economical to produce high volume items.Other disadvantages include:this process is only suitable for metals with high fluidity,and the casting weight must be between 30grams and 10 kilograms.
Normally,some porosity will be arised for the last batch of castings.Therefore,no heat treatment or welding can be applied,because the gas in the gap will be expanded if heated,which will cause internal defects.