HOT CHAMBER MACHINES Die casting is a manufacturing process for producing accurately dimensioned, sharply defined, smooth or textured-surface metal parts. It is accomplished by forcing molten metal under high pressure into reusable metal dies. The process is often described as the shortest distance between raw material and finished product. The term, "die casting," is also used to describe the finished part.
The term "gravity die casting" refers to castings made in metal molds under a gravity head. It is known as permanent mold casting in the U.S.A. and Canada. What we call "die casting" here is know as "pressure die casting" in Europe.
HOW ARE DIE CASTINGS PRODUCED?
First, a steel mold capable of producing tens of thousands of castings in rapid succession must be made in at least two sections to permit removal of castings. These sections are mounted securely in a machine and are arranged so that one is stationary (fixed die half) while the other is moveable (injector die half). To begin the casting cycle, the two die halves are clamped tightly together by the die casting machine. Molten metal is injected into the die cavity where it solidifies quickly. The die halves are drawn apart and the casting is ejected. Die casting dies can be simple or complex, having moveable slides, cores, or other sections depending on the complexity of the casting.
The complete cycle of the die casting process is by far the fastest known for producing precise non-ferrous metal parts. This is in marked contrast to sand casting which requires a new sand mold for each casting. While the permanent mold process uses iron or steel molds instead of sand, it is considerably slower, and not as precise as die casting.
TYPES OF MACHINES FOR DIE CASTING
Regardless of the type of machine used, it is essential that die halves, cores and/or other moveable sections be securely locked in place during the casting cycle. Generally, the clamping force of the machine is governed by (a) the projected surface area of the casting (measured at the die parting line) and (b) the pressure used to inject metal into the die. Most machines use toggle type mechanisms actuated by hydraulic cylinders (sometimes air pressure) to achieve locking. Others use direct acting hydraulic pressure. Safety interlock systems are used to prevent the die from opening during the casting cycles.
Die casting machines, large or small, vary fundamentally only in the method used to inject molten metal into the die. These are classified and described as either hot or cold chamber die casting machines.
HOT CHAMBER MACHINES
Hot chamber machines (Fig.1) are used primarily for zinc, and low melting point alloys which do not readily attack and erode metal pots, cylinders and plungers. Advanced technology and development of new, higher temperature materials has extended the use of this equipment for magnesium alloys.
Figure 1: Hot Chamber Machine. Diagram illustrates the plunger mechanism which is submerged in molten metal. Modern machines are hydraulically operated and equipped with automatic cycling controls and safety devices.
In the hot chamber machine, the injection mechanism is immersed in molten metal in a furnace attached to the machine. As the plunger is raised, a port opens allowing molten metal to fill the cylinder. As the plunger moves downward sealing the port, it forces molten metal through the gooseneck and nozzle into the die. After the metal has solidified, the plunger is withdrawn, the die opens, and the resulting casting is ejected.
Ningbo Pacific Casting Machinery Factory products f actory is specialized and engaged in aluminum pressure die casting, zinc die casting, and electric aluminum castings and vehicle spare parts, the production of zinc die casting has been supplied to many factories in China . Meanwhile, our products also cater to the to international buyers with strong competitiveness. Relying on our excellent international practice ,the deep understanding of east and west culture , as well as broad, stable, long-term trade with domestic and foreign customers and efficient quality management system, we are willing to generate mutual benefit, and hand in hand seek communal development with domestic and foreign partners. Die Casting,Pressure Die Casting,Aluminum Die Casting,Alloy Die Casting,Zinc Die Casting,Die Casting Machine Parts,Investment Casting,Aluminum Investment Casting,Carbon Steel Casting,Alloy Steel Casting,Stainless steel casting,Sand Casting,Green Sand Casting,Resin Sand Casting,Iron Sand Casting,Aluminum Casting,Aluminum Casting Alloys,Aluminum Casting Die Process,Aluminum high pressure die casting,Aluminum Pressure Die Casting,Aluminum Gravity Casting,Aluminum Sand Casting,Aluminum Precision Casting,Iron Casting,Ductile Iron Casting,Grey Iron Casting </li>
Hot chamber machines are rapid in operation. Cycle times vary from less than one second for small components weighing less than one ounce to thirty seconds for a casting of several pounds. Dies are filled quickly (normally between five and forty milliseconds) and metal is injected at high pressures (1,500 to over 4,500 psi). Nevertheless, modern technology gives close control over these values, thus producing castings with fine detail, close tolerances and high strength.