Unlike the hot chamber die casting process, cold chamber solves the corrosion problem by separating the melt pot from the injector components. In the cold-chamber process, metal is transferred by ladle, manually or automatically, to the shot sleeve. Actuation of the injection piston forces the metal into the die—this is a single shot operation. This procedure minimizes the contact time between the hot metal and the injector components, which helps to extend their operating life.
It is possible to cast lower melting point alloys using the cold chamber process but when you consider the advantages of the hot chamber process it usually makes more economical sense to use the hot chamber method for metals like zinc and magnesium.
There are different processes and recommendations for each different metal. If you are interested in starting a new die casting project, it is best to involve our team of engineers early on during the design process to utilize our expertise with design for manufacturing.
Components of the Cold Chamber Die Casting Machine
During cold chamber die casting, the molten charge, which consists of more material than is required to fill the casting, is ladled from the crucible into a shot sleeve where a hydraulically operated plunger pushes the metal into the die. The extra material is used to force additional metal into the die cavity to compensate for shrinkage, which takes place during solidification.
The main components of a cold chamber die casting machine are shown below. Injection pressure of over 10,000psi or 70,000KPa can be obtained from this type of machine.
Operating sequence of the cold chamber die casting process.
The die is closed and the molten metal is ladled into the cold chamber shot sleeve.
The plunger pushes the molten metal into the die cavity where it is held under pressure until it solidifies.
The die opens and the plunger advances, to ensure the casting remains in the ejector die. Cores, if any, retract.
Ejector pins push the casting out of the ejector half of the die and the plunger returns to its original position.
Visit our die cast process page to view a short video on the differences between the hot and cold chamber die casting processes.
Aluminum Die Casting Company
Dynacast works with customers all over the world to bring customers ideas to life with the highest quality precision engineered metal components on the planet. We have both cold-chamber and hot chamber capabilities that include both conventional and multi-slide die casting. If you are looking for a partnership to help you apply new tools and technologies, or help you fully realize your design vision, let us help you move your business forward, contact our team today to get the conversation started.