Injection Moulding Machines

7 Machines

Powerful injection moulding machines for plastics processing

Plastic parts, produced by injection moulding, are widespread. This is why injection moulding machines are considered important in plastic processing. The used machinery market supplies strongly vary according to screw diameter, clamping force, controlling system, year of manufacture and operating hours. An injection moulding machine is designed for series production. The liquefied plastic granulate is pressed in the mold, cooled and ejected as a finished plastic part. At Surplex you will find used injection moulding machines from ARBURG and other leading manufacturers. We sell high quality used machines all over Europe.

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Buy and sell used injection moulding machines at good prices on


  1. What is an injection moulding machine?
  2. How do injection moulding machines work?
  3. Using a plastic injection moulding machine in modern manufacturing facilities
  4. Where to buy a used injection moulding machine?
Used injection moulding machine in a factory

What is an injection moulding machine?

An injection moulding machine is used to produce plastic parts and components for a wide variety of applications. The plastic used to create these parts is injected into the mould under heat and pressure. It is then cooled until it hardens into the specific shape required. Most injection moulders consist of two main parts: the clamping unit and the injection unit. The mould is held in place either horizontally or vertically with clamps, which are usually controlled by hydraulics or powerful magnets. While there are still some hydraulic injection moulding machines around, the majority are now mechanical or electric. The latest machines are far more precise than they used to be, and they’re capable of much higher levels of productivity.

  • Central production tool for plastic products
  • Very complex machines
  • It is made up of 5 components
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How do injection moulding machines work?

An injection moulding machine consists of a feed, a backflow valve, an injection nozzle, and injector unit and a double cylinder. The raw material of plastic pellets or granules is fed into the machine via a material tank. The individual particles of plastic rub up against each other, which creates a significant amount of heat. Eventually, the heat created starts to melt the plastic granules, and a plastic “paste” develops. Pressure is then used to blast the molten plastic through the injection nozzle and into the mould. After the plastic has cooled (which takes just a few seconds), the shell of the mould is split in half by the backflowvalve. The finished plastic part is released by the ejector unit and drops into a container ready for checking and retrieval.

Injection moulding machine in use

This process of manufacturing plastic parts and components is now very accurate, but it results in a large amount of waste. An advanced injection moulding machine collects this waste efficiently through product and injection channels are kept separate. The moulds used in an injection moulding machine can operate with either a cold runner system or a hot runner system. The cold runner system involves a simple channel that is carved into the mould. The hot runner system is usually more costly, and it involves the use of cartridge heaters to keep the plastic hot in the runners. Although more expensive to operate, this system reduces waste, as the remaining plastic in a hot runner can be injected into the next part.

Using a plastic injection moulding machine in modern manufacturing facilities

A modern plastic injection moulding machine is capable of creating very precise component parts for use in many different industries. Fast, efficient and usually very reliable, these machines are capable of producing many injection moulded parts in a relatively short period of time. However, the average injection moulding machine has the potential to be dangerous, so only qualified and experienced specialists use them in large-scale manufacturing operations. The double cylinder can become extremely hot, so great care must be taken in the installation, maintenance and use of these powerful items of machinery.

Detail of a used injection moulding machine

Many smaller businesses still use manual machines, but large-scale manufacturers save time and money by using automatic versions that improve safety and reduce production costs. Robotic equipment is often used for the retrieval of products, as this speeds up manufacturing and reduces the risk of serious injury.

Where to buy a used injection moulding machine? is an online auctioneer specialising in used machinery for metalworking and woodworking. While we may not have the perfect injection moulding machine for your organisation right now, we are constantly sourcing new equipment from liquidation sales and companies upgrading their existing production lines. Among the respected used plastic injection moulding machine manufacturers often featured in our auctions are STORK, KRAUSS MAFFEI, ENGEL and ARBURG. Sign up to our newsletter to receive news of our next online auction in advance.