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March 9, 2017

Plastic Injection Moulding: From Design to Delivery.

Injection Moulding is a growing industry, and demand has been increasing for plastic injection moulders. However, despite its importance in the industry, the actual process behind plastic injection moulding is still a mystery to many people. This blog post is being written to try and explain the process behind plastic injection moulding, from the design to delivery.

  1. The first step in the process is the creation of the mould. This is a solid template that the plastic is injected into to create the plastic shape. They are manufactured to the proper specifications, and must feature both the mould shape and the cylinder in which the injection drill and plastic can go in.


  1. The actual machine used for injection moulding can differ depending on the product. Moldwel’s machines range from 35 tonnes to 328 tonnes, and the products they can make range from 0.1 grams to 1050 grams.


  1. The mould is clamped into the Clamping Unit of the machine that is appropriate for the product to keep it secure during the plastic injection and cooling. It must be set so that the injection unit, the large drill, can enter.


  1. Plastic materials, usually in the form of pellets, are fed into the cylinder of the mould. This is then melted down to a molten form. A motorized screw within the heating cylinder forces the molten plastic to the end of the cylinder.


  1. Once the plastic has accumulated at the end, the injection process starts and a carefully controlled screw or ram slowly feeds the plastic via drilling, or injecting, through the cylinder and into the mould.


  1. After the plastic is injected into the mould, there is a “Dwelling” phase where pressure is applied to make sure every single cavity within the mould has been filled with plastic.


  1. After pressure has been thoroughly applied, the plastic is allowed to cool within the mould and set form.


  1. The clamping unit is opened up after the plastic has been allowed to cool. The two halves of the mould open and allow for easy removal of the plastic product.


  1. An ejection rod, an ejection plate, or a blast of air will help push the plastic from the mould, resulting in a completed plastic product. The plastics produced can range from individual pieces of larger items to complete products themselves such as first aid boxes or electronic enclosures.


If you would like some more information on plastic injection moulding, contact us today.