Vacuum Die Casting can be thought of as an upgraded version of the traditional pressure die casting. It is a high-pressure die casting assisted by a vacuum pump to remove the air entrapped within the die cavity. That’s why the process is also known as Vacuum-assisted High-pressure Die Casting. Vacuum Die Casting is mainly adopted to reduce some casting defects in parts that occur due to air entrapment.
So, die casting manufacturers who want to ensure better quality for the produced parts will opt for a vacuum-assisted die casting machine.
Vacuum Die Casting process is almost similar to any pressure die casting technology with the only variation being the creation of vacuum during the process. Vacuum-assisted die casting can be applied for both Hot Chamber and Cold Chamber Die Casting.
The common process of Vacuum Die Casting is explained below:
Firstly, the metal alloy is molten
The molten metal is moved into the shot chamber with the help of a plunger in Hot Chamber machines and using a ladle in Cold Chamber Machines
Then vacuum creation and metal injection under high pressure is carried out
Air will be removed from the die cavity and which will enable the molten metal to uniformly reach all recesses
Then it is left to solidify and cool down
The completed casting can be retrieved after ejecting the die
Vacuum Die Casting greatly reduces surface defects and any major surface finishing processes may not be needed.
Now, the vacuum creation during the process is usually carried out in three ways.
Metal is injected after vacuum creation
The metal injection is done simultaneously with Vacuum creation
Metal injection and Vacuum creation is actuated with sensors
So, the Vacuum Die Casting process may slightly vary depending on how that particular die casting machine works.
VACUUM DIE CASTING ADVANTAGES
Vacuum Die Casting has helped manufacturers overcome many problems associated with traditional die casting. Here the major benefits of Vacuum Die Casting are discussed in detail.
Porosity is a common problem involved with die casting. It is almost impossible to completely get rid of porosity in traditional die casting techniques. But with Vacuum Die Casting you can expect to produce parts with little to no porosity.
No Surface Defects
Die casting machines that are not perfectly vented will cause air entrapment inside the die cavity. It can cause surface defects like blisters and blowholes. You may not be able to repair these defects and have no choice but to discard the part.
Better Mechanical Properties
Vacuum Die Casting can yield parts with better mechanical properties. Metal is more densely packed due to reduced porosity. This significantly increases the mechanical strength and enhances some other properties as well.
You don’t have to worry about providing thin walls in vacuum-assisted systems. Because of the negative pressure created by the vacuum, the molten metal manages to reach narrow recesses. So, the chance of miss run is omitted in Vacuum Die Casting.
Increased Production Capacity
Theoretically, Vacuum Die Casting would take almost the same amount of time as any regular die casting method. But, Vacuum casting significantly reduces defects in parts and gives a better surface finish. So, many post-processing operations are not required in vacuum die casting. This will save both time and cost for the manufacturers.
Without proper quality control regular die casting yields many defective parts. Some defects may be treated while sometimes you will have to reject the parts. Vacuum Die Casting reduces possible die casting defects and reduces waste during production.
Enables Heat treatment and Welding
Normally die cast parts are not suitable for heat treatment. Because of the gas pores present inside die castings, surface blisters will form due to high temperatures. Vacuum die casting omits this issue and allows heat treatment for die castings of certain metal alloys. The produced parts also have better weldability as well.
As you can see, Vacuum Die Casting has many benefits. But, you will need a well-maintained die casting machine with a proper amount of vents and overflows for the best results.
VACUUM DIE CASTING APPLICATIONS
Vacuum Die Casting is becoming more popular in many industries due to its ability to produce higher quality parts. Die Casting Manufacturers are also shifting their focus on Vacuum Die Casting.
Vacuum Die Casting is commonly used in the following industries,
These industries need high-quality and durable parts for their products. Traditional die casting may not be able to meet the strength and quality requirements. So, more and more manufacturers are starting to provide vacuum die casting solutions to customers.
REDUCE PRODUCTION COST WITH VACUUM DIE CASTING
Vacuum Die Casting is a more sophisticated process than usual and some extra processes are involved. And Vacuum-assisted system will generally be more expensive. So, Vacuum Die Casting should be more expensive than a traditional process. Right? That’s not entirely correct though. Because Vacuum Die Casting can greatly reduce defective parts during production. You can also provide thinner walls that allow manufacturers to save more material as well. So, due to less wastage, the production cost is reduced as well.
There is another factor in the quality and strength of parts. Die Casting is undeniably the most cost-effective manufacturing method for mass production of parts. But die casting is not applicable for ferrous metals.
In case you have a very high strength requirement, you may need to go to costlier manufacturing methods that can cast ferrous metals. Luckily, Vacuum Die Casting can make your parts suitable for Heat treatment. Vacuum-assisted Aluminum die casting can be heat treated to significantly increase its strength. So, you can still get the perks of the economy of Aluminum die casting with Vacuum Die Casting.
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