The climbing phase:
- The 1st step is to prepare the die halves for casting by cleaning the faces of each die then applying lubrication or release agent.
- Once the die has been prepared, the die halves are closed and clamped together with pressure applied from the die-cast machine.
- The clamping force will depend upon the size of the machine but must be more than the opposing force trying to open the die during the casting process.
The injection phase:
- The ingots are added to the furnace and kept molten at a set temperature according to the metal being used.
- The molten metal is transferred to an injection chamber and injected into the closed die pressure ranging from 1000 to 20,000 psi.
- The pressure is maintained while the metal solidifies.
- The amount is injected into the die is known as the ‘shot’
- The injection of metal into the die is very short, this ensures the metals do not start to solidify before the die is completely filled.
The cooling phase:
- After the injection is complete, the molten metal needs to solidify before the die is opened.
- The cooling time will depend upon the part geometry as well as the metal thermodynamic properties.
- The wall thickness of the parts plays a big factor in the cooling time, the thicker the wall section the longer the cooling time required.
The ejection phase:
- After the cooling time has elapsed, the two die halves can be opened.
- An ejection mechanism then pushes the solidified casting out of the die.
- The force of the ejection will be determined by the size of the part, bearing in mind, the part shrink during the cooling process and tends to stick to the die surface.
- Once the part has been ejected, the die can be closed ready for the next injection cycle.
The trimming phase
- During the cooling and solidification phase, the casting will solidify as a complete cast unit which includes the part, flash, and any runner system
- This excess material must be trimmed off to leave just the main cast product.
- Method of trimming includes trim tools, band saw are manually clipping.
- Any trimmed metal is either scrapped or recycled if permitted.
Advantages of die casting:
- Die casting is fast
Die casting can be produced in seconds each part and quantities of hundreds to thousands of metal parts each day.
- Near net shape
Die casting are produced “near net shapes” no matter how complex the shape are how tight the tolerances are.
- Lighter weights
Die casting are stronger because of the material surface skin not the thickness of materials so parts can weigh less with thinner casting wall thicknesses.
- Die casting is versatile
Many more part shapes and sizes can be produced using the die casting manufacturing process.
- Die casting are durable
Die castings parts are metal and have a long service life.
- Die castings are inexpensive
Die castings are fast to produce and useless material. Die casting are typically less expensive than most other metal parts manufacturing processes.