high pressure die casting - die casting คือ
High pressure die casting is able to produce castings economically at a fast speed.
These castings can be made up of various holes, threads, grooves, which are characterized by high dimensional accuracy and good surface finish.
They are able to save metal very well and require little or no surface treatment.
The main basis for pressure die casting is to push the molten metal into the mold or mold under considerable pressure.
The machine used for this purpose operates on one or two systems: in the hot chamber machine, the metal is kept in the crucible inside the machine, and the pressure chamber that transports the metal to the mold is located in the metal slot.
This kind of machine can be operated by pneumatic, or more often by the action of ram to generate pressure.
The cast metal of the cold chamber machine is kept in the heat preservation furnace, transferred from the heat preservation furnace to the pressure chamber, through a spoon or special automatic device, and forced into the mold through ram.
Some simple machines are hand operated, but fully automatic machines are more commonly used for high productivity.
In pressure die casting, precision molds using complex multi-part designs are therefore very expensive and are exposed to harsh working conditions due to continuous changes in high pressure and high temperature.
For the production of zinc and zinc alloy castings, the mold can be made of non-alloy steel, but for alloys of magnesium, aluminum, copper and these metals, the mold is usually made of hot-
Working Steel with greater durability.
Another development of high pressure die casting is vacuum die casting.
The castings it produces have a better finish than ordinary high pressure castings.
There are two systems, the mold is either closed in the hood that drains the air, or installed in the holding furnace under the casting machine, so when the air is discharged from the mold, the metal is sucked into the mold, and compacted, based on this principle, a cast iron manufacturing process was developed.