Die casting is to use very high pressure to fill the melting into the pattern in a very short time, normally in 0.01~0.2 second. Die casting is mostly suitable for high volume aluminum casting or zinc casting parts’ making. Due to the fast filling it ‘s very easy to have pin holes inside the castings. The die casting parts can not be heat treated accordingly. Some very complex casting with complex inner cavities could be difficult to be made by die casting.
LOW PRESSURE CASTING
Low pressure casting is mostly for aluminum casting or zinc alloy casting making. The pouring mold will be metal pattern. The melting will be pushed into the pattern for pouring by a kind of low pressure gas eg. air or inert gases with pressure around 0.01~0.05Mpa. Low pressure casting can ensure good filling of the mould and good casting quality.
Gravity casting is also mainly for aluminum casting or zinc alloy casting making.
The pouring process is finished by gravity of the melting. Resin cores can be put into the metal patterns to create complex casting’s structure.
Investment casting is dedicated for precision castings’ production. It can create better surface quality and dimensions’ precision than lost wax. It is also for steel casting , alloy steel casting, stainless steel castings’ making. The main difference of investment casting to Lost wax casting is that investment casting is using ludox for adhesive material during the wax shell’s making. And the wax for this process is called middle temperature wax which is different from what is used in lost wax casting process. The wax used in lost wax casting process is normally called low temperature wax. Middle temperature wax can keep the wax patterns in more stable dimension, shape and structure in stock , dipping adhesive , taking sands and drying operations. This will create more precise wax shell mold and finally create more precise casting blanks.
Sand casting can be used for grey iron casting, ductile iron casting, aluminum casting. There are three kinds of molding processes for sand casting. They are manual molding, semi-machinery molding and automatic molding. Automatic molding line is currently mostly for iron castings making.
Automatic molding machines include two kinds of part line: horizontal part line molding and vertical part line molding. DISA line uses vertical part line molding. SINTO ling takes horizontal part line molding. Normally vertical part line molding is faster than horizontal part line molding. But horizontal part line molding can accommodate more complex cores’ assembly and location for more complex structure parts.
The basic grey iron casting process include patterns design and making, molding, melting , inoculants action of the melting, nodular operation ( only for ductile iron) , pouring, cooling, shaking out, de-gating and after-treatment ( deburrs, grinding , shot blast).