The 6 Types Of Plastic Molding Explained

The 6 Types Of Plastic Molding Explained

We often think that aeroplanes, computers, cars, and other novel innovations are some examples of great inventions in the modern era. Although these types of progress are crucial, have we thought about the complex manufacturing processes, design applications, and materials that their production demand?

In manufacturing, we can use various materials to create products, and one of these materials is plastic. Various products can be made using plastic. As such, many manufacturers use plastic moulding to make the manufacturing processes more manageable and create the products’ essential parts.

What Is Plastic Molding?

Moulding is how manufacturers shape liquids or flexible materials through a rigid frame known as a matrix or mould. When it comes to moulding plastics, a liquid polymer, such as polypropylene or polyethylene, is used as the material to be shaped in a mould or matrix. Likewise, different levels of pressure and heat are used to make a plastic product, such as a hose or water bottle

Plastic moulding started in the late 19th century to cater to the need for plastic billiard balls. Plastics were found to be an excellent substitute for the typical ivory billiard balls during that time. In 1868, John Wesley Hyatt found a suitable process to create billiard balls by injecting celluloid material into a rigid frame.

In 1872, these two brothers patented the first moulding machine. It’s the first plastic injection moulding machine that someone ever created. The purpose of this machine is to act as a basic plunger to put plastic into a mould via a heated cylinder.

That said, here are the different plastic moulding methods to learn.

The 6 Types Of Plastic Molding

The process involved in plastic moulding has come a long way since it was first introduced. Currently, a business can use six types of plastic moulding techniques to manufacture its plastic products.

1. Extrusion Molding

In this type of plastic moulding, hot melted plastic is squeezed into a shaped hole to make a lengthy shaped plastic product. The shaped hole in which the hot melted plastic is pressed is called a ‘die.’ The cross-sections differ and can be formed based on the manufacturer’s requirements. Likewise, the typical shapes formed are solid rectangles, round, T-shapes, and L-shapes.

Some examples of products produced using extrusion moulding are straws, polyvinyl chloride (PVC) piping, and hoses. A manufacturer can create these plastic products in large amounts as extrusion moulding makes it possible to produce them in similar shapes continuously.

Know that it’s much less expensive to conduct extrusion moulding than other moulding techniques. The reason is that machine and the die isn’t that complex. Yet, this moulding process has limitations concerning the product type a business can make.

2. Rotational Molding

Rotational moulding, also known as rotomoulding, is a manufacturing technique where a liquid or powder resin is placed into a metal mould that is then rotated fast in an oven. This is done until the liquid or powder fills up the whole surface of the mould, with all the walls getting smoothly thick. After the process, the manufacturer will then allow the product to lose its heat. After the liquid plastic has been shaped, it is removed from the mould.

Like extrusion moulding, rotational moulding is less costly. Yet, the process involved is slower. It’s because this plastic moulding process is tailored for large, hollow containers like recycling bins, pet houses, or storage tanks.

Overall, if you need professionals to conduct rotational moulding, visit us here at Rennd.

3. Injection Molding

Injection moulding is the most used plastic moulding technique for various manufacturers. It’s treated as versatile as multiple parts ranging in shape and size can be developed using this method. Also, this process is suitable for manufacturing parts with excellent quality and significant volume.

This moulding method is quite similar to extrusion moulding. The only point where these two plastic moulding methods vary is that injection moulding directly injects the melted plastic at a high temperature into a customized mould. After the molten plastic is placed directly into the mould, such mould is allowed to lose its heat and then opened to get the solid plastic material.

Car parts and surgical appliance parts are some of the products made using this moulding process. Likewise, engineers and designers can benefit from products that are made with improved flexibility using extrusion moulding.

4. Compression Molding

Compression moulding is the process of putting heated plastic within a heated mould. This mould is then closed to compress the plastic into its ideal shape. After the mould and plastic are cooled, the part is then taken out. Often, the plastic ends in the form of sheets, yet it can also be in bulk. After the activity, the heat generated during the procedure guarantees that the end product will be strong enough.

Likewise, this process can also be less expensive. Yet the less costly it will depend on the cavities’ volume, the surface finish, and the design’s intricacy. When you’re developing products in large quantities, rotational moulding can be suitable as the cost per part will be affordable.

5. Blow Molding

Blow moulding is a manufacturing method for creating hollow, thin-walled plastic materials. This is typically a straightforward technique that’s chiefly utilized when there’s a need for uniform wall thickness.

In this moulding method, a machine changes the raw plastic into a thermoplastic molten tube through its high temperature. After that, the molten tube, also called a parison, is blown similarly to a balloon and is squeezed against the mould’s walls to create the final product and shape.

This process is suitable for creating various products such as plastic bottles, cases, fuel tanks, and drums. A business that needs a substantial number of parts for its products can benefit from it.

6. Thermoforming

Thermoforming is a moulding method in which a plastic sheet, known as thermoplastic, is warmed up to a flexible forming temperature. It is ideally shaped within a mould and then trimmed to make the final product. Thermoforming is suited to have plastic products such as lids, disposable cups, fridge liners, and clamshells.

This process uses significantly low pressure. That’s why the moulds are very affordable. Thermoplastics like polypropylene, acrylic, and polycarbonate are examples of materials that are most suitable for thermoforming.

Final Words

Moulding can be ideal for manufacturing different products, and so is plastic moulding. There are various methods for conducting plastic moulding. For one, we can apply extrusion moulding to create a lengthy-shaped plastic material. Also, rotational moulding is ideal if one wants a cost-effective moulding process. Lastly, using injection moulding is suitable for those who want a versatile method to manufacture their products.

These are some examples of plastic moulding processes discussed in this article. Overall, learn more about plastic moulding by sending an inquiry to us through our contact page.

23rd November 2022