Plastic Injection Moulding – How it Can Benefit Manufacturing!

Plastic Injection Moulding

Plastic injection moulding is an incredibly versatile way of producing products. It is preferred in manufacturing due to its numerous advantages, such as increased efficiency. Since it handles intricate designs with high consistency and precision, it only makes sense to choose it.

How does plastic injection moulding work?

Many industries use plastic components as a way to enhance and build a wide range of products. Injection moulding is frequently used in manufacturing plastic components due to its high-quality performance.

In fact, research suggests that the injection moulded plastics market is likely to grow by 4.6% by 2028. However, the process is complex and must be controlled effectively to ensure the quality of the final parts. This is why it is vital to partner with specialists in injection moulding large plastic products, as they will know precisely how to ensure the process is done correctly.

Injection moulding involves heating the plastic material to a molten state, then injecting it into a closed mould tool, where it cools and solidifies into the desired shape. The mould tool is then opened, and the finished part is removed.

What are the advantages of plastic injection moulding?

There is a reason why plastic injection moulding has become so popular – it offers many benefits over other methods for manufacturing plastic parts. However, there are some disadvantages too.

For instance, high-pressure injection moulding is associated with different potential issues, like deformation because of internal stresses and risk of sinkage. Fortunately, there is a way to overcome these challenges, namely through structural foam moulding. This technique ensures an even distribution of the cooling plastic’s internal pressure, thus decreasing the internal tension within the final product.

Let’s further discuss the advantages of plastic injection moulding.

Complex part design

Injection moulding can handle complex shapes and create millions of identical parts. To maximise quality and precision, it’s vital to focus on design, which is critical in making high-quality and consistent parts. On the contrary, a poor design can lead to costly processing mistakes.

According to moulding professionals, fundamental design elements are vital so the injection process can work correctly. They include rib design, wall thickness, corner transitions and vents placed adequately.

Fast production

Unlike other methods, plastic injection moulding is a fast process, having a high production output rate. Speed depends on factors like the mould’s size and complexity, but the period between cycles is very short – between 15 to 120 seconds. This allows for a larger quantity of moulds to be produced in a short time, boosting profit margins and revenue.  

Enhanced strength

Strength is an essential factor to consider in the design of a plastic injection moulded part. It enables the designer to determine whether the part needs to be rigid or flexible to adjust the integrating gussets or ribs. It is also vital to understand how the part will be used and the type of environment it will be exposed to.

If you find the right balance of design considerations, you’ll meet the part’s need for stability and strength. Material selection is also a critical factor that impacts the part’s strength.

Low labour costs

Unlike other types of moulding, plastic injection moulding comes with relatively low labour costs. This is because the process is automated, so most of it is performed by robotics and machines controlled by a sole operator.

Hence, automation reduces manufacturing costs because the overheads are dramatically reduced. Moreover, reduced labour means the overall expenses in the manufacturing process decrease, and the cost saving will be passed on to customers.

Multiple finishes

Most injection-moulded parts consist of a smooth surface finish similar to the desired final look. But a smooth appearance is not ideal for every application. The plastic injection moulding process allows for creation of surface finishes that don’t need secondary operations. The flexibility of the finish is a primary characteristic of the process, both in terms of engraving and unparalleled textures.


The only way to produce high-output plastic parts is through a consistent and repeatable process that allows for designs with tight tolerances. The consistency of the injection moulded process is unique, enabling the repetition of great results across several manufactured components. This is associated with better cost-effectiveness and low defect percentage.

Lightweight products

This aspect is vital for many industries using plastic components to their advantage. Plastic injection moulding reduces the weight of a specific part without compromising strength, flexibility or hardness. High-strength thermoplastics can nowadays replace metal components easily, as there is no difference in their dependability and strength.

Making the most of the plastic injection moulding process

The first step in ensuring a successful plastic injection moulding process is realising that it involves a lot of details. Therefore, some changes may be required so that the process can meet a given product’s needs.

Whether modest or large-scale, production runs are based on optimization and detail, and the process should enable the machines to run without much interruption. It is also crucial to make efficient use of the materials, and one essential tip is to reduce the shot size. 

According to experts, lowering the shot size by 10% of the machine’s total capacity allows the application nozzle to work the check ring better. This helps reduce wasted material considerably. Using adequate thermoplastic is an efficient way to stretch the materials budget as far as possible.

Also, you want to pay attention to preventive maintenance, so make sure to prioritise cleaning the moulding equipment. Consider the thickness of the product’s walls, too. As a recommendation, you should follow two valuable rules:

  • avoiding sharp corners to the advantage of rounded features;
  • keeping each wall about 40-60 per cent of the adjoining walls’ thickness.

Our takeaway

Injection moulding eliminates the need for further work once the manufacturing process is completed. This is because the finished parts are high quality, and their appearance is already good enough.

Nowadays, plastic injection moulding is sustainable, as the scrap plastic produced in manufacturing is reused; therefore, the process ensures waste is reduced as much as possible.

Plastic Injection Moulding article and permission to publish here provided by Trevor Davis. Originally written for Supply Chain Game Changer and published on February 5, 2023.