A plastic injection machine is an indispensable tool for a wide industry dedicated to the transformation of this material into different objects.

This is so in part because plastic is a highly versatile material with the ability to adapt to multiple uses. But, for this to be possible, it is necessary to have precise machinery, capable of turning it into what we need.

Industries that manufacture plastic objects must invest in the appropriate technology to achieve quality production processes adapted to the needs of their customers. It is there where this type of machinery takes centre stage.

What material are we talking about?

First, let’s briefly recall what materials we use. To work with injection moulding, the so-called thermoplastics are used. These are, as the name suggests, plastics that become malleable when subjected to high temperatures. And, on the contrary, when they cool down, they harden; this means that they adopt the shape to which they are moulded. The thermoplastics most used today are polyethylene (high and low density), polypropylene or polystyrene. To achieve the profile we want in thermoplastics, it is necessary to have a specific mould. This is used, as we explain in the next section, to inject the molten plastic inside.

How does a plastic injector work?

In the first lines of this text, we already referred to the plastic injection machine as a machine. Specifically, it is the machinery necessary to inject a thermoplastic in a liquid state, or melted, into a mould with a certain shape. The moulds are almost always made of steel and aluminium, and it is important that they are very precise to absorb even the smallest characteristic that you want to give to the piece.

The injection of plastic to manufacture elements in this material is a process that does not modify the characteristics of the plastic. Only the state in which the material is present changes, from solid to liquid and, when the injection process is finished, the other way around. So, it is a reversible and physical process.

Parts of the injector

The machines in charge of the injection of plastics are made up of different parts:

  • The injection unit, in which the plastic is heated and takes care of injecting it in the molten state.
  • A closing unit in charge of containing the mould, opening and closing it. In addition, it also has a part ejection mechanism.
  • A control unit. Thanks to this system, the desired parameters can be established to carry out the procedure, to which we have already referred. We are talking about temperature, times, pressure and speed, variables that can be controlled. There are even some injector models that allow the extraction of data and statistics related to these factors.

Steps of the injection process

The injection procedure should be done in a certain order. A sequence and specific times are respected in order to achieve an optimal result through the proper operation of the injection machine.

What this means to manufacture the plastic part we want:

First of all, it starts with a plastic material that is usually supplied in granulated form. These granules are introduced into a cylinder that is part of the injector structure. Inside, the material is heated to a certain temperature until it is molten. Then, using a specific hydraulic pressure, the molten plastic is injected (introduced) inside the mould we have chosen. And finally, after a waiting time, the material cools down and is expelled and we have a solid plastic piece.


At Triana, we have very complete facilities. Our 2700 m² located in the industrial area of Barcelona and we have our own mould workshop, ISO 7 Clean Room for the manufacture of pharmaceutical containers and sanitary products and a printing area for the final decoration of the containers.

The mould workshop is prepared with the necessary machinery to carry out the repair and maintenance of these parts. And the injection room, which undergoes specific maintenance, is equipped with 16 injection machines from 50 to 320 Tm, of which six are in a clean room.

This investment in technology and equipment responds to our commitment to a job well done, quality and customer satisfaction. With almost 6 decades of experience, our track record is backed by the success of our products.

Contact us and we will explain to you all that we have to offer you.


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