Aluminium Casting Method

Aluminium High Pressure Casting in its simplest definition is the pouring of molten aluminium raw material via a runner at high pressure (400-1,000 bar) and speed (30-100 m/s) into a mould made of metal. The process of applying high pressure is continued until the solidification process is completed. Thereafter, the mould is opened and the process is finished off by removing the part from the mould using forceps. After the process of spraying the mould with separator oil, the mould is sealed and locked again in preparation for the next cycle.

The part taken from the mould is cut off from the runner area and processed, heat treated, coated, etc. as needed to create the finished product.

There are two types of applications of the die casting process. The first of these is the Hot Chamber and the second is called theCold Chamber application. The Aluminium Material‘s structure and characteristics play a decisive role in which application should be chosen.

Hot Chamber Machines:

In the production of materials with a low melting point, such as lead, zinc and tin, Hot Chamber Machines are used. When using the hot chamber casting method, the accuracy rate for the finished product is ±0.05 mm at completion. There are two types of hot chamber casting machines which vary according to how they operate.

1. Plunger Machines; The material in the crucible is melted and the construction comprises a cylinder which plunges into the crucible and which has a plunger inserted into it. This is how the process works for Plunger Machines. After the mould is closed, the plunger moves downwards, and the material that enters the cylinder is pushed into the mould.After the material solidifies in the mould, the plunger is pulled back and the mould is opened.
2. Pressure Machines; The material that melts in the crucible is filled into the mould with a plunge cell and a lever system. Pressure Machines these are usually not the preferred method for aluminium casting.

Cold Chamber Machines:

Cold Chamber Machines are commonly used for the casting of high melting point alloys such as aluminium, copper, magnesium. In these machines, the melting furnace is located in a separate section. Molten metal can be removed manually with a hand scoop or an automatic scoop and a larger amount is poured into “the cold chamber” of the part to be produced. It is compressed with a plunger to fill the mould cavity.

Advantages of the Aluminium Casting Method;

Constituting an indispensable method in the production process, the Method of Casting Aluminium has the following advantages.

• An Efficient Process: After investing in the mould, you can produce hundreds of thousands of identical parts using machining and additional labour. Particularly in the automotive industry, the Aluminium Casting Method is the answer to the problem of mass producing units.
• Stable and Repeat Production: With the precision in die casting, you can repeat orders especially engineering parts and make high-spec products.
• Special Finishing Operations: In line with customer requests, you can obtain parts with the desired surface roughness.
• Flexibility of Production: In addition to the surface quality, you can carry out the production of complex-shaped parts of different cross-sectional sizes.
• Longevity: Welding, riveting, etc. of complex-shaped parts can be produced without the need for a joining process. The production of parts in a single procedure increases the part’s strength. One other reason why parts produced in this way are durable is that they are heat resistant and dimensionally stable.
• Low Cost: Aluminium Cast Parts are cheaper than parts made with other metal alloys.

Drawbacks of the Aluminium Casting Method;

Although it has many advantages,the drawbacks to the Aluminium Casting Method also exist. These drawbacks, that may cause an engineer or manufacturer to think again when choosing casting processes when determining their preferred production method, are as follows.

• Casting sizes are limited. Very large pieces can not be cast.
• The design of their moulds is difficult.
• The investment cost of the casting machine and the associated auxiliary equipment is high.
• The cost of mould maintenance is high.
• The high degree of porosity in the casting complicates the heat treatment and welding processes.

Developments in Aluminium Casting

Continuous process improvements are made to increase the mechanic properties and sealing strength of the parts produced.

• The use of vacuum systems to expel gas trapped in the mould during casting,
• Heat treatment applications,
• The application of a semi-solid metal process,

The improvements made to Aluminium Alloys and to the pressure treatments are ongoing, and Aluminium Die Casting applications are spreading as an alternative material in every sector.

KALKANCI: The Aluminium High Pressure Casting Company

Combining historic experience with an innovative forward looking vision, KALKANCI can provide its services in a professional manner to meet all kinds of customer need for Aluminium High Pressure Casting. KALKANCI understands the different needs of each discrete sector and develops appropriate processes to meet each separately; continuing to work successfully with its customers in a range of countries. If you too want to receive the benefit of the professional service we can provide in this regard to complete your casting process error-free, please contact us.