How Low Pressure Die Casting Works?

How low pressure die casting works is simple, but it is not without its complications. The process of low pressure die casting involves increasing the cavity pressure until it reaches the required level of crystallization pressure, and then holding it there for a certain amount of time. There are two main types of low pressure die casting: gravity die casting and cold chamber die casting. Read on to learn more about how each one of them works.

Gravity die casting

In its most basic form, gravity die-casting is a method of metal casting in which molten aluminium is poured into a metallic tool. The molten metal is cooled to about 750 oC during the casting process. This method is highly efficient and produces high-quality castings. It is also very competitive, particularly for small-scale production and low-volume parts.

In this process, molten metal flows into every crevice of the mold cavity. The resulting product is characterized by smooth surfaces, excellent dimensional accuracy, and fast production. The low pressure and gravity processes are both highly compatible with the automotive industry. The advantages of gravity die casting are numerous. Below, we will compare the differences between the two methods. This article is intended to provide information on both of them.

High pressure die-casting requires the delivery of molten metal into the mould at a high pressure. The process is very complex, and moulds need to be hardened. Low pressure die-casting moulds can be made of cast iron, which has advantages over high-pressure die-casting. The lower cycling rate allows rapid cooling of the casting, preventing excessive heat buildup in the mould.

Cold chamber die casting

There are various applications of cold chamber die casting. The metal alloys used in cold chamber die casting are those with a high melting point, such as aluminum. This process is ideal for these types of metals as it provides high dimensional stability and lightweight components. Copper is another metal alloy that is commonly used for this process. It is high in strength and corrosion resistance, with good dimensional stability. Other metals used in cold chamber die casting include silicon tombac, which is a combination of copper and zinc.

Injection dies used for semisolid castings are very similar to conventional cold chamber die casting dies. The main difference is that the dies are reusable steel and are split into two halves, one fixed and one ejector. In semisolid die casting, a steel ejector pin is used to eject solidified castings from the die after solidification. This die type also includes a shot sleeve that has a pour hole in it.

To begin the process, the metal alloy is injected into a mold using a true injection plunger. The plunger remains forward to hold pressure while the casting solidifies. The molten metal is impacted by temperature changes, which affect the flow of metal and the mechanical properties of the material. An increase in temperature reduces tensile strength and yield, but increases ductility. This is dependent on the alloy used.