What Are The Different Types of Casting Processes

Here you will know all about Casting & processes

There has been a surge in the need for sophisticated and high-quality products as industrial demands and applications have increased. Fortunately, there are several casting methods that can produce complicated and precise products for a variety of applications and user needs.

It is vital to understand the pros and disadvantages of various procedures in order to select the best casting method for your manufacturing needs. This page includes a quick summary of several casting methods, as well as their advantages and disadvantages.

What is Casting Process?

The?casting process?is a method of producing desired-shape metal parts by pouring molten metal into a mould, hardening, and cooling it to room temperature. It is capable of creating sophisticated and detailed pieces of any size.

As a result, casting can make isotropic metal pieces in large quantities, making them appropriate for mass production. Furthermore, several forms of casting exist to satisfy specific user requirements, which vary depending on the material and mould utilised.

What are the different types of Casting Processes?

There are various types of?casting procedures, and each process has advantages and disadvantages depending on the user’s needs.

1. Sand Casting Process

Sand casting is a flexible casting process that can be used to cast any ferrous or non-ferrous metal alloy. It is commonly utilised in industrial units for mass production of automotive metal casting parts such as engine blocks, cylinder heads, crankshafts, and so on.

A mould made of silica-based substances, such as naturally-bonded or synthetic sand, is used in the procedure to generate the smooth mould surface. The mould surface is divided into two sections: cope (the upper half) and drag (the lower half) (the lower half). Using a pouring cup, molten metal is poured into the pattern and allowed to harden to form the final shape. Finally, excess metal is removed in order to finalise the final metal casting product.

The sand-casting process has some advantages as well as disadvantages.

2. Gravity Die Casting

Gravity die casting, also known as permanent mould casting, fabricates metal and metal alloys using reusable moulds made of metal such as steel, graphite, and others. This metal casting process can produce a variety of items such as gears, gear housing, pipe fittings, wheels, engine pistons, and so on.

The direct pouring of molten metal into the mould cavity occurs under the influence of gravity in this procedure. The die can be angled to adjust filling for optimum coverage. To make items, the molten metal is allowed to cool and solidify within the mould. As a result, the casting of materials such as lead, zinc, aluminium, and magnesium alloys, certain bronzes, and cast iron is becoming more popular. In contrast to conventional pressure casting procedures, this casting process fills the mould from the bottom up. The method, however, has a greater casting rate than sand casting. However, it is substantially more expensive due to the high cost of metal moulds. Check out its benefits and drawbacks below.

3. Pressure Die Casting

Depending on the pressure, there are two forms of pressure die casting. There are two types of die casting: low-pressure die casting and high-pressure die casting. High-pressure die casting is more commonly used in the mass manufacturing of complex geometries requiring high precision. Low-pressure die casting, on the other hand, is a preferred casting process for big and simple component production.

Nonferrous metals and alloys such as zinc, tin, copper, and aluminium are injected at high pressure into a reusable mould covered with a lubricant in this type of metal casting. To avoid metal hardening, high pressure is maintained throughout the quick injection procedure. Finally, after the process is completed, casting extraction and finishing are performed to remove any leftover material. In the process of filling the mould, pressure die casting varies from gravity die casting. Pressure die casting involves the injection of molten metal into a metal mould under high pressure. The molten metal is then swiftly solidified to generate the desired result.

Its benefits and drawbacks are summarised below.

4. Investment Casting

Investment casting, also known as lost-wax casting, is a method of producing metal castings by investing a wax pattern with refractory material and a binding agent to shape a disposable ceramic mould, and then pouring molten metal into the mould.

Investment casting is a costly and labour-intensive process that can be utilised for mass production or in intricate castings to make metal casting goods such as gears, bicycle trunks, moto discs, and blasting machine replacement parts.

The advantages and downsides are summarised below.

5. Plaster Casting

Plaster casting is identical to sand casting, however, the mould is composed of a material known as ‘Plaster of Paris.’ Plaster cools the metal more slowly than sand due to its limited thermal conductivity and heat capacity, which aids in achieving high precision, particularly for narrow cross-section pieces.

It is not, however, suited for high-temperature ferrous materials. Plaster mould casting allows for the production of small castings of 30 grammes as well as massive castings of 45 kilogrammes. The figure below, for example, depicts a cast component created by this process with a section thickness of 1 mm.

The advantages and downsides are summarised below.

6.?Centrifugal Casting

Centrifugal casting, also known as roto casting, is a method of producing cylindrical objects in an industrial setting using centrifugal forces.

The molten metal is poured into a prepared spinning die in this method of metal casting. At high pressure, centrifugal forces aid in the distribution of molten metal within the die.

There are three types of centrifugal casting processes: genuine centrifugal casting, semi-centrifugal casting, and vertical centrifugal casting. In contrast to pure centrifugal casting, semi-centrifugal casting uses a sprue to entirely fill the mould. However, due to constant spinning, molten metal adheres to the sides in genuine centrifugal casting.

Vertical centrifugal casting, on the other hand, uses directional moulding in the same way that genuine centrifugal casting does. Centrifugal casting typically yields rotational structures such as cylinders. Parts such as bush bearings, clutch plates, piston rings, and cylinder liners, among others. Furthermore, putting metal in the middle of the mould aids in the reduction of defects such as blow holes, shrinkage, and gas pockets. However, it is not appropriate for all metal alloys.

The advantages and downsides are summarised below.

7. Lost-Foam Casting

The lost-foam casting method is similar to investment casting except that the pattern is made of foam rather than wax. After the design is produced, it is coated with a refractory ceramic by dipping, coating, spraying, or brushing. The molten metal is then poured into the mould to create the desired product.

This process is applicable to a wide range of materials, including alloy steel, carbon steel, alloy cast iron, ferrous alloys, and others. The lost-foam casting process is used to make products such as pump housing, fire hydrants, valves, and fittings. Lost foam casting has various advantages, including high precision and accuracy production. However, this technique has a few disadvantages that make it unsuitable for low-volume uses.

The advantages and downsides are summarised below.

8. Vacuum Casting

As the name implies, vacuum casting is a type of casting in which manufacturing takes place under a vacuum pressure of 100 bar or less to exhaust gas from the mould cavity. To eliminate bubbles and air pockets, molten metal is poured into the mould cavity inside a vacuum chamber.

The vacuum evacuation of the die cavity prevents gases from becoming trapped within the cavity during the metal injection process. Finally, the metal is cured in a heating chamber before being extracted from the mould. The vacuum die-casting method is widely used in a variety of industries, including automotive, aerospace, electronics, marine, and telecommunications. As a result, structural chassis components and vehicle body elements are among the components produced by this manufacturing technique.

The advantages and downsides are summarised below.

9. Squeezing Casting

Squeezing die casting, in particular, is a promising casting process for safety-critical elements in automobile systems. Space frame joints, aluminium front steering knuckles, chassis frames, brackets, or nodes are examples. This metal casting process combines the advantages of casting and forging. For example, the high pressure used during solidification aids in the prevention of shrinkage and porosity. However, because of specialised tooling needs, it is not as common for large production as other casting procedures.

Liquid forging, also known as squeeze casting, is a metal-forming hybrid that combines permanent mould casting with die forging in a single operation. In this procedure, a specified amount of molten metal alloy is poured into a die and shaped under pressure. The metal portion is then heated to melting temperature and removed from the die.

The advantages and downsides are summarised below.

10. Continuous Casting

It enables the continuous mass manufacture of metal profiles with a constant cross-section, as the name implies. This style of casting is commonly used in the manufacture of steel bars.

Furthermore, vertical casting produces semi-continuous casting such as billets, ingots, bars, and so on. Molten metal is poured at a calculated rate into a water-cooled, open-ended mould, allowing a solid metal surface to form on the liquid metal in the core. Thus, metal solidification occurs from the outside in. After this operation is completed, metal strands can be removed from the mould indefinitely. Mechanical shears or moving oxyacetylene torches can be used to cut materials to predetermined lengths.

Continuous casting produces products that are generally uniform, consistent, and dense. However, it is limited to such uses. Other benefits and drawbacks include:

11. Shell Molding

Shell moulding is a mould-casting procedure that uses disposable moulds. It is similar to the sand casting process, except that instead of a flask of sand, the hardened shell of sand forms the mould chamber. The sand used in sand casting is finer, and it is combined with a resin so that it may be heat treated and cemented into the shell surrounding the design. Shell moulding is used to create industrial items such as gearbox housing, connecting rods, small-size boats, vehicle hoods, cylindrical heads, camshafts, valve bodies, and so on. The casting products have a smooth surface finish and are dimensionally accurate.

However, the size and weight limitations of the pieces are a constraint of this type of casting. Other benefits and drawbacks include:

Outsource Your Casting Needs to NabTech Engineering

It is critical to select the appropriate casting method and expertise for your products.?Nabtech Engineering, a prominent manufacturer of metal components, provides high-quality services. We service a wide range of businesses with years of experience. Our clientele includes everything from autos to home goods. It also applies to other industries, such as decorative products and street lights.