What to Consider When Purchasing a Used Injection Moulding Machine

What to Consider When Purchasing a Used Injection Moulding Machine
Kitmondo 01 Nov 2016

When buying large-scale machinery like plastic injection moulding machines, many individuals and companies opt for purchasing used equipment. This is primarily because used equipment has two major advantages over new equipment: price and availability. In general, used equipment tends to be significantly less expensive than new, and is also more likely to be immediately available. This can be advantageous for a multitude of reasons, such as providing a ready source of equipment for new market developments, or even business expansion.

It is important to understand the main components that make up the machine, and how it works. Injection moulding is a process in which a polymer is heated to a high plastic state and forced to flow under high pressure into a mould cavity, where it solidifies. By doing this, the injection moulding machine is able to manufacture a variety of plastic products. The two main parts of the machine are the injection unit and the mould clamping unit. The injection unit system is used for melting and homogenizing the polymer, and injecting it into the mould cavity. The clamping unit system holds the parts of the mould in place and keeps the mould closed during injection.

Mitigating purchase concerns

Some buyers may be concerned that purchasing a used machine could create difficulties when it comes to finding the exact size, brand, configuration, or model they would prefer, as well as apprehensions that the parts they’re purchasing are defective in some way. The reality, however, is that resellers usually sell their products because they are no longer usable in the marketplace they previously served, rather than because they are faulty. Nevertheless, it is imperative to know what to look for when buying a used injection moulding machine.

Customized to fit your needs

First and foremost, you should determine what your needs are for this new equipment:

  • Shot weight – usually measured in grams or ounces; the first step in selecting a suitable screw and barrel assembly
  • Size of equipment – should match the size of the items being moulded; avoid using large equipment to mould small items, and vice versa, to prevent them from being damaged or using too much energy
  • Clamping force – should be high enough to keep mould closed during injection

Useful tool: Injection capacity calculator - calculate shot weight and barrel capacity

Once you have determined the parameters of the injection moulding machine you need, make sure that the used machine you would like to buy has been fully tested and inspected prior to delivery. This ensures that the machine won’t suffer breakdowns once it is in your possession, enabling you to create high quality parts consistently and effectively without interrupting daily tasks for troubleshooting. In many cases, a test run of used equipment can be arranged before you agree to purchase, sometimes at no extra charge.

In addition to a physical or visual inspection of the machine, you should also be sure that fast delivery is possible, and that your purchase comes with maintenance records. Normally, machines can be ready for shipping in about a month, or even less if the parts are already in stock. Similar to buying a used car, the machine should come with a service history that includes production hours, showing where, when, or why the equipment was serviced. Detailed records can confirm that you are getting a machine that offers high quality, reliable performance.