maintenance of manifold of hot runner system

 

Injection MoldingWhen properly installed ,manifolds will operate trouble free. If a problem occurs it is usually due to heater or thermocouple failure or melt contamination.

 

 

 

HEATER/THERMOCOUPLE FAILURE

  • Let the tool cool down
  • Disassemble the hot half taking care when un-torqueing, not to bow or distort manifold.
  • Undo screws holding in the heater and remove heater.
  • Replacement heaters come with manifold, for extra spares contact supplier and have the manifold’s approval drawing or A—- number ready.
  • New heater should be installed in groove with the use of a soft hammer. Take care when installing new heater not to bend or distort the element as this will damage the heater.
  • Test heater insulation then reassemble hot half.

CLEANING OUT RUNNERS

  • To clean out the runners, let tool cool and dismantle.
  • Remove end plug grub screws, (Note it may be necessary to heat manifold to loosen screws if they are stuck).
  • Before you can extract the end plugs you must remove the M4 grub screws which lock the end plugs in place. This is normally located on the top of the manifold, but may be at the bottom of the heater groove, in which case you will need to remove the heater as well. You will need to use a puller to extract the end plugs.
  • Then heat the manifold to the BOTTOM range of its processing temperature and using a hot wire with a hook on the end, try to hook out the melt just as the outer layer of plastic melts in the runner.Do not under any circumstances attempt to blow out hot plastic with an air gun.take extreme care not to scratch bores.
  • If this is not successful, heat the manifold to full operating temperature and allow to so ask for 20-30 minutes and use a tight fitting rod of soft material e.g. Aluminum to push out the plastic from the runners.
  • If the manifold has deviation plugs, contact supplier before attempting dismantle.
  • Carefully refit end plugs, making sure alignment of end radii is correct, apply anti seize to threads on set screws.
  • Torque to figures in manifold catalogue.
  • Refit manifold.