In a standard metalworking process, die casting is performed by pushing metals or alloys into a mold cavity at a significantly increased temperature. Majorly, the process is utilized when metallic parts are required in massive quantities as it delivers a fast production rate.
With different metal requirements, different methods are used to get the desired shape and characteristics. Multiple die casting methods are available depending on the production volume and applications. Let us have a glance.
Majorly, there are two types:
- Hot chamber machine
- Cold chamber machine
However, two significant casting process types have numerous variations: low-pressure, squeeze, vacuum, and semi-solid die casting. Different die casting processes are picked based on unique needs, parts, size, geometry, and complexity.
HOT CHAMBER DIE CASTING PROCESS
The process, also known as the hot die casting process, begins as the injection mechanism of the machine gets dipped in a molten metal bath of a furnace which is connected to the machine through a gooseneck (a metal feeding system). After that, the injection cylinder plunger rises, and the port in the injection cylinder unlocks, allowing the molten metal to load the cylinder.
Further, as the plunger gets down, it seals the port again and compels metal to stuff the cavity via the gooseneck and nozzle. Ultimately, the plunger is withdrawn, and the metal gets set in the cavity. Later, the die unlocks, and the casting releases.
BENEFITS OF THE HOT CHAMBER PROCESS
- Helps in quicker production – like for minor components, produces up to 18,000 shots per hour
- Builds parts with less porosity
- Metal is molten inside the machine
- It brings the lowest wastage
- Longer life due to low melting point
COLD CHAMBER PROCESS
When it comes to the cold chamber machine, the procedure goes as the molten metal is filled inside the chamber part of the injection cylinder or shot sleeve before pushing it into the mold. Moreover, since the sleeve is not heated, the process is comprehended as cold chamber die casting. Therefore, the metal melting pot does not have a corrosion issue as it is different. The procedure starts when molten material or cold chamber die casting metals are transferred from the furnace to the shot chamber via the pouring hole. Further, the plunger closes the cold chamber port and propels the metal into the mold cavity. The pressure ranges between 30Mpa and 150MPa.
This method is generally preferred for high-melting-point alloys of aluminum, copper, and magnesium, along with other metals, like ferrous metals that can also be cast.
COLD CHAMBER DIE CASTING BENEFITS
- Better strength
- Thicker metal castings due to advanced pressure during injection
- Lower maintenance cost
- It gets excellent dimensional precision to the part
- Potential high-speed production.
- Simple-to-carryout operation.
DIE CASTING TYPES: HOT CHAMBER VS. COLD CHAMBER
There are many differences between Hot chamber and cold chamber die casting. Some of them are:
LOCATION OF FURNACE
A built-in furnace is available in the hot chamber die casting setup; the molten metal is sent directly to the die cavity. On the contrary, in cold chamber equipment, the melting furnace is outside; hence an automated or manually operated ladle is used to move the molten material into the machine.
TIME OF PRODUCTION
Hot chamber machines have shorter casting cycles yet higher production. At the same time, cold chamber machines have longer casting cycles but lower production.
The hot chamber die casting setup deals better with low melting point alloys. Some common metal alloys used are lead and zinc. Furthermore, the cold chamber die casting setup works well with high melting point alloys. Some common metal alloys are Brass, Copper, Magnesium, and more.
The hot chamber die casting setup requires minimum safety. While the cold chamber die casting setup needs more safety measures.
Besides these two, there are many other variations of the die casting process such as,
LOW-PRESSURE DIE CASTING
When it comes to fabricating vehicle wheels and other aluminum components, this procedure of Low pressure die casting is used. The reduction of the feeders from the process assures high casting outcomes. Around 0.7bar to 1 bar is the normal Low pressure die casting pressure range.
In the low-pressure die casting process, a pressurized furnace fills the die with metal. Then, the holding furnace injects the molten metal into the base of the mold. Moreover, the metal remains in the die until it solidifies.
VACUUM DIE CASTING
Vacuum die casting is used to make applications that utilize post-casting heat treatment. The benefits of this procedure include decreased turbulence and limited gas inclusions. The procedure of vacuum die casting aluminum also assures improved resilience and lower porosity to the material.
The vacuum casting process is very much the same as any normal die casting process with slight differences. At first, the vacuum pump creates a vacuum in the die cavity and injects the molten metal into the cavity via pressure. Furthermore, release the final piece from the die once it gets solidified.
SEMI-SOLID DIE CASTING
This casting method, also known as thixo-forming, offers the lowest porosity and highest density in the casted material. This procedure offers a counted benefit of good accuracy. It is most generally utilized for non-ferrous metals, including Aluminum and Magnesium alloys.
In the procedure, the machine first trims the material into slugs to make it get heated. As soon as the metal turns into a slushy form (between solid and liquid), a shot sleeve drives it into the mold cavity and leaves it to harden.
SQUEEZE DIE CASTING
When it comes to toughening fiber, this procedure is primarily used and is generally linked to molten aluminum. It permits casting metals and qualifies for much lower fluidity.
During the procedure, the molten metal loads up in the open die, which squeezes closed, moving the molten part into the open molding portions. As a result, the process later produces overly dense products.
GRAVITY DIE CASTING
The procedure is ideal for applications that need a better selection among high-pressure and sand casting. The Gravity die casting is more robust than sand casting and asks for minimum investment costs than high-pressure die casting.
BENEFITS OF GRAVITY DIE CASTING
- Ideal when automatic or massive production is needed
- The minimum investment needed for tiny to medium production
- The final output comes with excellent mechanical properties that are further fit for heat treatment
- The Gravity die casting process is apt when parts with intricate shapes need to be created
Automotive parts such as turbos, engine blocks and pistons, and engine cylinder heads are known as some of the most intricate aluminum casting productions; Aluminium gravity die casting is preferred for their production. It is ideal for various industries, from lighting to kitchen components.
Die casting is a helpful manufacturing process. It is ideal for building parts with precise dimensions, that too, in huge production quantities. All the types mentioned above are used differently based on different applications. Find the right Gravity die casting suppliers in the USA and get the best solutions!