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ChinaSavvy is a die casting manufacturer that operates strictly to ISO 9001:2008 standards and prides itself in being one of the most affordable and professional die casting companies operating within China today.
With offices in the United Kingdom, China and the United States, we are the company to use if you are in the market for world class engineering at affordable Chinese prices.
Die Casting Materials
As one of the most specialized die casting companies in China, we can deliver precision die cast parts using the following popular casting alloys:
Die Casting Processes
The following processes are used for zinc, aluminum and magnesium die casting:
- Cold-Chamber Conventional Die Casting
- Hot-Chamber Conventional Die Casting
- Multi-Slide Hot-Chamber Die Casting
Cold-Chamber Conventional Die Casting
A molten charge (which is more material actually needed to fill the casting) is ladled from the crucible into a shot sleeve. From here, a plunger, hydraulically operated, is used to push the molten metal into the die.
The extra material from the molten charge serves to force extra material into the cavity, supplementing the shrinkage that takes place during the solidification process. Machinery used in this type of die casting process can obtain pressures of over 10 000 psi (or 70 000 KPa).
The cold-chamber casting process:
- First, the die is closed after which the molten material is ladled into the shot sleeve.
- The hydraulic plunger is now used to push the molten material into the cavity of the die. The plunger is held under pressure until the solidification is complete.
- The die is now opened. The hydraulic plunger advances in order to ensure the castings stays in the ejector die. If there are any cores present, they will react at this stage.
- In the final stage, the ejector pins will expel (or eject) the casting from the ejector die. After this has been successfully completed, the hydraulic plunger will return to its original position.
Hot-Chamber Conventional Die Casting
Die casting machine
|Injection fills mold
|Injected metal cools
|Molded part is ejected with sprue
|Finished cast part with sprue
Hot Chamber Conventional Die Casting is typically favoured when dealing with zinc and alloys with a low melting point. However, it can also be used for magnesium alloys due to advancements made in material, technology applied, and the processes and techniques used.
The injection mechanism (made up of the cylinder and plunger) in this casting process is submerged in the crucible which contains the molten material to be casted.
The hot-chamber casting process:
- First, the die is closed and the piston is raised. This rise of the piston now allows for molten metal to fill the cylinder.
- The plunger is now moved downwards in order to seal the port that is pushing the molten metal into the cavity through the nozzle and gooseneck. The plunger is held there under pressure until the material (or molten metal) solidifies.
- The third step entails the opening of the die and, if there are any cores, they will react at this time. When opened, the castings stays in one die half - the ejector side. The plunger is returned to its original position which in turn allows the residual molten metal to flow back through the gooseneck and nozzle.
- In this stage, the ejector pins now eject the casting out of the ejector die and, as the plunger uncovers the filling hole, molten metal flows through the inlet, refilling the gooseneck as it did in the first step of the process.
Multi-Slide Hot-Chamber Die Casting
Enabling the production of accurate and complex castings, multi-slide die casing uses four perpendicular slides (in some cases six slides at angles that are not 90°) within the tool itself.
The tool consist of:
- The die block (which has either a core and/or a cavity in its face. Together, these aspects form the runner and the cavity into which the molten metal will be injected into).
- Sliders (onto which die blocks are mounted)
- The crosshead (into which the sliders are designed to precisely fit)
- A cover plate (responsible for holding all the tool components together)
Slides are controlled by computer software and moves independently from each other while ejection is accomplished through air blasting.
Pneumatics are used instead of hydraulics, allowing for higher cycle speeds. To ensure that the casting tool is sufficiently held together during the injection process, hydraulic thrusters and mechanical toggle mechanism are used.
Advantages & Disadvantages of Die Casting
- Excellent dimensional accuracy
- Smooth cast surfaces
- Reduces, or eliminates, secondary machining processes
- Rapid production rates
- High initial cost
- Limited to high-fluidity metals
- A certain amount of porosity is to be expected
Die Casting Products
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