Plastic injection moulding is a marvel of modern engineering and is capable of manufacturing a diverse range of products for countless industries. One pivotal part of injection moulding is the machines – the heroes behind many of the household items we use day to day. In this blog, we will dive deep into the plastic injection moulding machine so we can understand and appreciate the process that bit more.
What is a Plastic Injection Moulding Machine?
A plastic injection moulding machine transforms pellets of raw plastic into a range of different products from toys and kitchenware to automotive and medical components. It works by melding heat and pressure to morph plastics into different shapes ranging from simple products to more complex designs.
The plastic injection moulding machine is an important part of manufacturing as it can produce large quantities of products in a quick, efficient, and affordable way.
When Was the First Injection Moulding Machine Invented?
The first injection moulding machine dates all the way back to 1872 when John Wesley Hyatt created this machine that changed how billiard balls were produced. This set the stage for many more plastic products to follow.
How Do Plastic Injection Moulding Machines Work?
Here’s a breakdown of how plastic injection machines work from a technical point of view.
1. Plastic pellets are fed into the machine’s hopper.
2. These pellets are then moved into the machine’s barrel by means of a rotating screw where they are heated until they turn into a molten state.
3. The molten plastic is pushed forward by the screw in the injection unit into the mould cavity under pressure, this is the “injection” phase of injection moulding.
4. The plastic is injected into the mould precisely in order to fill the entire space and capture all intricate details.
5. After the mould is filled, it cools and hardens within a specific timeframe to ensure it’s strong, durable, and aesthetically pleasing.
6. Once solidified the mould opens and the plastic part is ejected from the mould.
Industries That Rely on Plastic Injection Moulding Machines
Plastic components have a wide variety of applications across numerous industries. This is all thanks to their flexibility, durability, safety, and affordability. Here are just some of the industries that heavily rely on the plastic injection moulding machine.
Aerospace
The aerospace industry relies on the plastic injection moulding machine to mass produce parts like turbine blades, housings, chassis components, bezels, lenses, and much more. The process of injection moulding allows aerospace businesses to precisely replicate many of the same design quickly and efficiently.
Electronics
Electronic companies rely on plastic components as it provides casings that are resistant to dust, moisture, and other external influences with a high level of protection. Plastic parts also provide durability and optimal performance in electronic devices from remotes to computers.
Automotive
There are many businesses in the automotive industry that work closely with plastic injection moulding companies to create durable, lightweight, and safe automotive components. Plastic parts in the automotive industry are precisely designed to comply with safety regulations.
Medical
Plastic injection moulding machines are essential in industries like medical. This is because it offers a high level of precision and quality which are essential. Xray components, test kits, and much more are created with the help of plastic injection moulding machines.
Food and Beverage
Plastic injection moulding is commonly used in the food and beverage industry to create food containers, filtering components, conveyor systems, reusable drinks cups, and much more. However, the injection moulding process for this industry must be compliant with UK food and safety standards.
Construction
Injection moulding machines produce durable plastic components like adaptors, frames, and casings to protect electronics. This process is therefore vital in the construction industry due to the products’ strength, weather resistance, and lightweight nature.
Household
The plastic injection moulding machine is essential for creating many of the appliances and furniture you have in your home. From garden tools and supplies to in your living room, plastic injection moulded components are everywhere, including drawers, high chairs, toys, containers, light fixtures, and even toiletries.
Core Components of a Plastic Injection Moulding Machine
By delving into the anatomy of a plastic injection moulding machine, we can see the complexity of the machine and the various essential components that help create a range of products.
Injection Unit
· Hopper – this is where plastic pellets enter the machine.
· Barrel – this is the heated section where the pellets are melted. The barrel works with the heating bands to ensure the plastic reaches the optimal melting temperature.
· Heating bands – these encircle the barrel and provide the necessary heat to melt the pellets.
· Screw – this component mixes the molten plastic and injects it into the mould cavity.
· Nozzle – this is the point of exit for the molten plastic from the injection unit into the mould. The nozzle ensures precise delivery of the plastic into the cavity.
Clamping Unit
· Mould – this is the custom-designed element that shapes the molten plastic.
· Clamping system – this system holds the mould halves together during the injection and cooling process to help ensure precision.
· Ejector system – once the plastic has cooled and solidified, this component releases the finished product from the mould gently to ensure no breakages.
Control System
· Control panel – this is the ‘brain’ of the machine and enables technicians to set and monitor all parameters of the process such as temperature, pressure, and time.
Hydraulic System
· Pumps and motors – these provide the power that the machine needs for its operation.
· Valves and hoses – these control the flow of the hydraulic fluid which is essential for the machine’s precision.
Cooling System
· Cooling channels – these are located within the mould to circulate coolant and reduce the temperature of the molten plastic.
Safety Features
· Safety Gates – these prevent operator access to the machines' moving parts during operation to ensure a safe working environment.
· Emergency stop buttons – these allow for the immediate cessation of the machine’s operations in case of an emergency to protect the operator and the machine.
Types of Plastic Injection Moulding Machines
Plastic injection moulding machines are classified into different main types and cater to specific manufacturing needs and preferences. Here’s a breakdown of the types.
Hydraulic Injection Moulding Machines
Hydraulic machines are known for their strength and high clamping force which makes them ideal for producing large and complex parts. Due to their reliability and durability, they’ve been an industry standard for years.
Mechanical Injection Moulding Machines
As the name suggests, mechanical machines use a mechanical system to open and close the mould. These machines are less common today, but they are simple and effective and suitable for certain applications where high precision isn’t completely critical.
Electric Injection Moulding Machines
Electric machines use electric servo motors for precise control and energy efficiency. They offer better precision, are faster, and have lower operating costs. However, they have a higher initial cost.
Hybrid Injection Moulding Machines
Hybrid machines combine the benefits of hydraulic and electric machines to offer a balance of performance, efficiency, and cost-effectiveness. They have a high clamping force and speedy cycle times but have a higher up-front cost.
Specialised Injection Moulding Machines
Specialised machines are designed for niche applications like multi-material moulding or micro-moulding. They offer enhanced capabilities for complex parts and unique materials but are more expensive and less flexible compared to other injection moulding machines.
Expert Injection Moulding by Pentagon Plastics
At Pentagon Plastics, we offer expert plastic injection moulding to a range of different industries. We provide bespoke solutions for our customers from our dedicated manufacturing facility in the UK and provide a variety of services from mould tooling to full manufacture. Get in touch with us today if you’re interested in our plastic injection moulding services.
