An Insight into Magnesium Die Casting

It was during the industrial era that the scientific community and manufacturers worked hand in hand to create processes that could be used for mass production of products. Many new inventions and plenty of advanced technologies were developed during this period of time. These manufacturing processes have been fine-tuned and optimized over years in order to maximize production and reduce costs. One such technique that revolutionized the manufacturing industry is magnesium die casting.

In layman’s terms, die casting is a process that involves forcing hot molten metal into a mould and allowing it to cool. When the magnesium alloy cools, it takes up the shape of the cast. Then the cast can be removed to release the manufactured part. This method may seem to sound very simple, but there are lots of factors that the manufacturers have to be taken into consideration when the manufacturers set up the entire unit for magnesium die casting.

It is not just magnesium alloy that is used for die casting. A variety of non-ferrous metals such as zinc, aluminium, tin and their alloys are also used in this technique. The choice of the metal alloy and other manufacturing conditions depends on the process and the product. The casting time and the amount of material required depends on the die cast design and process flow. If properly planned and executed, the die casting process can be used to mass produce products without loss of quality or waste of raw material.

Magnesium die casting is preferred for many product manufacturing processes as it is lightweight yet strong. This alloy is used in the production of parts and components for automobiles, hand tools and scores of other appliances. This alloy is also preferred for processes in which the operating temperature is more than 120 degree Celsius. Even if the alloy is cast at such high temperature, its surface flatness and bolt tension is maintained. So, you will get superior quality results each time.

When compared to other casting metals, magnesium alloy offers greater corrosion resistance and better machining. Moreover, this metal alloy has high conductivity, superior dimensional stability and stiffness. So, manufacturers can use this metal alloy for processes that involve casting wafer thin wall products.

After magnesium die casting process is completed, the components can be painted or powder coated. However, the casts will require pre-treatment in order to ensure proper adhesion and smooth results. 

Aluminium Alloy Vs Magnesium Alloy Die Casting

Die casting is a process in which molten metal is forced into a chamber at very high pressure. When the metal cools, it forms the shape of the mould. In order to prevent any type of reaction, the cast is made of non-ferrous metals such as steel, copper, aluminium, zinc, magnesium and their alloys. This metal casting process is relatively simple and doesn’t need a large investment. 

Both magnesium and aluminium alloy are used for die casting process. Both have their own advantages and disadvantages.


Melting Point

The melting point of the metal is the first point of comparison between the two alloys. Magnesium has a melting point of 1800 LB while aluminium has 2500 LB. As aluminium alloy has a lower melting point than magnesium alloy, it will make an economical choice. Again the choice of alloy depends on the type of furnace and melting pot.


Melt Loss

Another point of difference between the two alloys is the melt loss, which depends on the type of die casting technique used. Generally during magnesium casting, melt loss of 5 to 25% is seen while aluminium has less melt loss of 5 to 10%.


Cost

Another point that is generally taken into consideration while choosing either of the two alloys is the cost of production. Magnesium has a quick solidification rate, so, it doesn’t need high pressure like aluminium to be solidified. In many ways, it can be seen that magnesium alloy is more economical than aluminium die casting.


Machinability

While comparing the machines used to die cast both alloys, it is seen that magnesium is advantageous over aluminium. Magnesium machines have natural lubricity and quickly dissipate heat, which enables carving deep cuts without damaging the surface finish. Plus, more magnesium castings can be made as the die caster has a high tolerance to this metal than to aluminium alloy. When you compare the lifespan of carbide tools used to machine magnesium and aluminium, you will see that they last up to 10 times longer when used with magnesium.


Applications


Generally aluminium is used in die casting of automotive parts such as clutch pedal and support bracket. If the die caster is using a hot chamber die casting machine, then magnesium die casting requires 160 metric ton. For, aluminium die casting, it will require a 550-650 metric ton cold chamber die casting machine to do the same. Here, if you compare the price with the machine size required, then magnesium alloy becomes a more affordable option.