Die Casting - Advantages and Disadvantages

Update:Oct 19 2016
Summary:

Die casting is a method in which molten metal is presse […]

Die casting is a method in which molten metal is pressed into a mold cavity under high pressure. The metal is hardened to obtain the desired shape. Recently, plastic molded parts have replaced die casting because they are cheaper and lighter than die-cast parts. The die casting may be performed using a cold chamber or a hot chamber process.

On Die Casting Process

Die casting is an extensive non-expendable technology in which metals are forced into the mold cavity under high pressure. Die casting molds known as molds can be reused to produce castings of various sizes, shapes, and wall thicknesses. The mold cavity design has a complex design that enables the production of complex shapes of precision, surface finish and attractiveness.

Die Casting History

Early in die-casting, only low-pressure injection methods were used, but currently over 4,500 pounds per square inch are cast using high-pressure casting techniques such as extrusion casting and semi-solid die casting. Initially, only tin and lead were the type of molds, but now magnesium, copper and other alloys are also cast using this very popular method.

Die Casting Process

In this process, the molten metal or other material is forced into the cavity of the steel mold under high pressure. The mold is a two-part mold made of alloy tool steel - a retainer mold half and an ejector mold half. The mold or mold is made of a stamp of the part to be cast. There are four types of molds:

A single chamber produces a component

Multiple cavities produce multiple identical parts

Unit molds produce different parts at once

Combining molds produces several different components for a component

Molten metal is injected into the mold at high pressure and high speed, which helps to produce castings that are as smooth and precise as the original mold. The pressure is maintained on the mold until the hot metal solidifies. When the metal is hardened, the mold is opened to remove the casting.

There are several variations in the basic processes that can be used to produce castings for a particular application. These include:

Squeeze Casting - A method by which a molten alloy is cast without turbulence and gas capture at high pressure to produce high quality, dense, heat treatable components.

Semi-solid forming - a process in which semisolid metal blanks are cast to provide dense, heat-treatable castings with low porosity.

The use of alloys

Aluminum, copper, lead, zinc and tin-based alloys are mainly used for die casting.

Automation

In modern times, precision die casting machines are used to ensure consistent quality control. Each mechanically processed die cast is different in the way the molten powder is poured into the mold. Automation for lubricating molds, pouring metal into chambers, and the like. Two methods, called thermal and cold chamber methods, are used for die casting.

Application

Die casting is best suited for casting medium-sized parts with complex details. Die casting is the largest casting technology used in the manufacture of consumer goods, commercial and industrial products such as automobiles, toys, sink faucet parts, connector housings, gears and the like. Most die castings are made of non-ferrous metals such as aluminum, magnesium, and the like.

Advantage

Economic process that can be used for a wide range of complex applications

Parts have a longer service life, dimensional accuracy and tight tolerance

Post-processing can be completely eliminated

Can be fully automated process

Mold can be used repeatedly.

Shortcomings

Casting weight must be between 30 grams.

Castings must be less than 600 mm (24 in)

High initial cost.

Limited to high-flow metals.