Difference Between Low-Pressure and High-Pressure Die Casting

Posted by Icasting Machining on January 8th, 2021

Since the early 20th century Aluminum components have been used in the automotive industry. From long time, the different processes for manufacturing these parts in terms of their economic efficiency and suitability have been compared by automotive experts.

Low-pressure die casting     

Like high-pressure die casting, to a fixed and moving machine plate, here also the parts of the die are attached but the machine is vertically aligned. Beneath the fixed plate the furnace for the molten metal is placed.

To the furnace applying pressure of up to max is reliable. The molten metal is pushed by 1 bar (usually aluminum and magnesium) into the die chamber up through an intake port. Sand moulds can be used although it is usually a permanent mould. Against gravity, the molten metal’s upward movement act. This naturally ensures solidification that is also possible from top to bottom.

High-pressure die casting

To a fixed plate of machine, one half of the die is attached and to a movable one on a horizontally aligned die-casting machine, the other one is attached. Because of the high pressure used in aluminum high pressure die casting when pouring – up to 1,200 bar – the bolts must have a high locking force that holds the two halves of the die together.

Cold-chamber die casting machines are mainly used for aluminum alloys because these have a relatively high melting point. Here, at the exterior side of melt, the casting assembly is placed. To a shot chamber the molten metal is input, from where the metal is driven into the die by a piston. The two parts of the die are opened once the metal has cooled and solidified and by ejector pins the casting is automatically ejected from the die.

Things required for the automotive world

As everyone knows, to increase efficiency and reduce CO2 emissions the sector is being forced. Low-pressure die casting is able to use sand cores in engine technology to implement what is known as a closed deck design for an engine block – this indicates that in the low-pressure die casting process for demoulding the cooling jacket contours are not needed.

A more rigid engine block is produced by this; and weight is saved and performance is improved when taken together with the enhanced properties of material. For parts used in the structure and the chassis the same technology is applied by aluminum high pressure die casting machines.

Benefits of High-pressure die casting

• Short casting cycles
• Well suited to automation
• Suitable for thin-walled components
• Smooth surfaces are offered by aluminum high pressure die casting china

Benefits of Low-pressure die casting

• Provides very good strength values
• Less complicated machine and die technology
• High dimensional accuracy
• Complex geometries is possible as sand cores can be used
• No need for feeders as there is use of higher materials
• Whole process is well-suited to automation