Injection Moulding

 

WHAT IT MEANS TO SHAPE TOMORROW

OVER 50 YEARS OF INJECTION MOULDING

Since 1965, RGE has been at the forefront of Plastic Injection Moulding, constantly pushing to adapt and grow within an industry that is ever-evolving with new technologies and innovations. Our vast experience in plastic injection moulding spans countless industries, and has equipped us with the skills to take on any project, not matter how big or small. 

With over 150 plastic injection moulding machines and a clamp force range of 25 to 3150 tonnes, we house the largest injection moulding machines in the UK, and provide plastic injected parts to an international client base as one of Europe’s leading suppliers.

TWIN SHOT

​Over moulding two materials in one moulding cycle

GAS INJECTION

​Using nitrogen gas to create hollow parts

LARGE TONNE PRESS

​RGE is home to the largest injection moulding machines in the UK

WHAT IS INJECTION MOULDING

Injection moulding is a mass production process, capable of creating multiple units of solid plastic parts in one go, repeatedly with fast cycle times, providing the capacity to manufacture multiple parts at the same time. This is a high volume manufacturing process that also allows for products to be produced in complex and intricate detail. 

Injection moulding produces little to no waste throughout the entire process, due to the precision of the mouldings created. We have the capability to produce mouldings in a variety of different materials from polypropylene to high-performance engineering polymers as well as recycled plastics.

THE INJECTION MOULDING PROCESS

Step 1: The mould tool is securely mounted into a moulding machine, with the two halves of the tool held in place by clamps.

Step 2: Plastic pellets are fed into the moulding machine using a hopper, and then pass into a heated barrel to melt the granules. Within the barrel, a reciprocating screw plasticises and compresses the material, driving the molten plastic towards the mould tool.

Step 3: A nozzle forms a seal between the barrel and the mould tool. Under high pressure, the molten plastic is passed from the barrel through the nozzle, and into the cavity of the mould tool. Tools can contain multiple cavities to produce more than one part each time.

Step 4: Temperature controlled water or oil circulates the body of the mould tool to cool the plastic within. As the plastic cools, it solidifies to the shape of the mould cavity.

Step 5: The moulding machine uses its moving platen to open the mould tool, and ejector pins extend into the mould cavity to push the part out. Often, a robot collects the finished moulding from the mould, and places it on a conveyor belt or moves it to the final working area. The pins then retracts to their original position, allowing the mould to be closed and the cycle repeated.

INJECTION MOULDING CYCLE TIMES

Cycle time is defined by the time it takes to make a complete part, starting with closing the tool, injecting the plastic, cooling the polymer under pressure, opening the tool, and finally ejecting a full part. Many factors can affect the cycle time, such as wall thickness, plastic type, part design, and the mould's cooling design and material. 

A shorter cycle time will improve manufacturing efficiency, which allows more parts to be made for the customer in a shorter time. Achieving a short cycle time is paramount to be able to supply a competitively priced component.

MULTI-CAVITY TOOLING OPTIONS

Each tool used in the injection moulding process can consist of one or multiple cavities. These cavities can be identical to each other to produce multiples of the same item, or unique to allow one tool to produce different sets of components at the same time in one cycle. 

For high volume production requirements, it is ideal to design a tool that will make more than one identical part at a time, saving time and energy to create several parts in one cycle. Accurate tool making and precise process controls are crucial for ensuring that all cavities are created equally within a multi-cavity mould, allowing for each part to be of the same consistently high quality.

ADDITIONAL INJECTION MOULDING SERVICES

RGE is able to offer a variety of additional services to complete the assembly and finish of any product in house, and can cover the full spectrum of any injection moulding requirement.

  • Automatic application of self-adhesive labelling – often used to add branding or information to a finished product.
  • Computer Controlled Pad (Tampo) Printing – detailed marking and stunning graphics can be applied to cooled components, offering a premium finish to any product.
  • Simpler decorations can also be added, such as company logos or product markings. Application of hot-foil blocking, usually carried out during the cooling cycle of the plastic injection moulding process.
  • Plastic components can be assembled using ultrasonic welding, or linear vibration welding – RGE make complex base components for products such as tumble dryers using the linear vibration welding technique, joining lower and upper parts with a water tight welding joint to make a stable and accurate complex plastic component.
PLASTIC INJECTION MOULDING AND THE ENVIRONMENT

The injection moulding process produces little-to-no waste due to the precision and accuracy seen throughout the entire production process. Only the exact quantities of plastic material are used to create and shape the final product, and any excess plastic found in channels or air vents during the moulding can be reground, melted, and used to create the next moulding.

The quality and intricacy of the tools that RGE produces ensures high levels of consistency in end products, reducing the amount of scrap product. Only one tool is used to create hundreds of thousands of products, each moulded to the exact requirements of the customer, with the finished product ejected from the moulding machine within seconds.

Products produced using plastic injection moulding are extremely rarely single-use. Plastic products produced in this way are designed to be durable and long lasting, making use of the benefits of plastic as opposed to natural alternatives that will decompose or rust, capable of being used again and again. For long lasting items that will be in regular use, natural materials will be unable to match the life span of a single plastic product.

Smooth plastic surfaces are far easier to maintain than even their closest counterparts, making them ideal for use in the medical industry, for example, where objects need to be regularly disinfected allowing them to be used multiple times. Items such as school chairs and storage boxes are designed to last for years and withstand a lot of wear and tear, which reduces waste produced when replacing damaged or worn items.

Whilst plastic waste is a huge environmental problem seen across the globe, thermoplastics can be re-ground and set in a mould an infinite number of times. Reground plastic can be easily reused to create a new product once the original item reaches the end of its life, creating a cyclical process and keeping plastics out of landfill.