hot runner nozzle jamming

2012-02-09

In the plastic injection process,hot runner takes important role,error wii be happened in the processing,such as hot runner nozzle jamming.Usually the hot runner nozzle jamming, majority result of runner plastic melt temperature excessively low. For example: The hot runner nozzle structures, the mold transport water, thermocouple quality, heating coil density portion and so on. Also has or installs the period in the manufacture the mistake. For example:hard foreign matter in the hot runner, plastic raw material to have the metal to truncate and so on.
Below simple introduction some runner jamming reason and nozzle jamming solution.
different nozzle type:Ordinary -runner jamming:
1. the runner gate temperature is too low. Reduces the runner place cooling rate, to crystal plastic hot mouth model whether to choose appropriately, whether mold's heat insulation cavity does suffice enough.
2. the hot sprue's front end temperature is too low. Reduces the area between hot sprue sealing compound and mold's contacted. Must have the heat insulation gap in hot sprue's front end.
3. the quantity of runner heat is insufficient. Enlarges the diameter of heat insulation cavity, reduces the sprue point's length, checks the spure point in the runner concentricity.
4. the nozzle temperature is too low. Increases heating coil's power. Checks the hot runnerl controls temperature.
5. foreign matter jamming. The heat of dissociation flow channel system, eliminates the foreign matter.
Pin valve type runner jamming:
1. the valve needle is too short or distortion. Check up or replacement.
2. the runner damage, checks the valve needle length whether too long.
3. the cylinder, air/oil leak. Check up cylinder connection place and in examination cylinder's seal packing collar.
4. the valve needle and the runner place contact is inappropriate, reduces the runner place mold temperature,lengthens the valve needle.
5. the cylinder pressure is unsuitable, to increase/ reduce pressure.
6. pressure maintaining time too long. reduce pressure maintaining time.