Injection Moulding Process

To manufacture a finished plastic injection moulded component there is a process that we follow. To offer an insight for those without experience into how we achieve this we have provided a detailed breakdown of the process below:

labelled image of injection moulding process

Image supplied courtesy of Rutland Plastics

preparing material

1. Prepare the mould

  • Clean the mould tool to remove mould protection.
  • Clear the tool vents to prevent gassing issues.
  • Ensure that the tool is suitably lubricated to function.

Colourful plastic parts

2. Prepare the material

  • Issue the required amount of thermoplastic material to complete the production run.
  • Remove moisture from the material in a dedicated dryer in line with processing parameters when required.
  • Mix the material with masterbatch to achieve the required colour (If the material is compounded to the finished colour this is not necessary).

3. Set up process

  • Clamp the mould tool in the press.
  • Configure the ejection system of the mould tool in the moulding machine.
  • Set the guide process parameters including temperature control.
  • Prepare working area with additional ancillary equipment as required. This may include conveyor belts, collection boxes, tool shielding, work benches etc.
  • Load the thermoplastic granules in to the feeder hopper.
  • Optimise the settings to achieve a product to meet expectations.

Diagram of process

4. The injection moulding process

  • The prepared thermoplastic is poured into the Hopper.
  • The material funnels down into the screw which is heated to melt the plastic.
  • The barrel is heated at staged temperatures along its length (approx. 5 zones) to allow the material to solidify and to move along the screw.
  • The screw rotates which moves the material forward with the pressure and speed determined to fill the cavity efficiently.
  • When the material exits the nozzle at the end of the barrel it is injected into the feed channels of the mould tool.
  • The feed channels allow this material to flow into the open cavity of the mould tool which forms the shape of the finished product.
  • The mould tool is held at a constant temperature to allow ease of material flow and to also draw out the heat from the product after injection, so, the material sets off to a solid form.
  • After a predetermined cooling time the mould tool is opened when the moving platen carrying the ejection half is retracted.
  • The mould tool opens with the product held in the ejection half of the tool.
  • The ejection system then moves forward to release the product from the mould tool.
  • The product is gathered in the collection box after the cycle is complete or the parts can be picked from the tool as required.

After the moulded parts are produced they will be removed from the machine area. On occasion components will require additional post moulding work to achieve the final finished part before being finish packed in line with the specified requirements.