Do mould parts need to be serviced regularly?

Regular servicing of mould parts plays a vital role in the life of the mould. The annual maintenance program required for each injection moulding position depends on the different mould cycle times. Here are some mould accessory overhaul tips that every mould user can use to ensure the effective operation of mould components such as hot runners, heaters, guide pillars and ejectors, moulding inserts, etc. to prevent unexpected situations from occurring.

1. Look for warning signs of rust or moisture at the air diffusion holes. If you find rust or moisture near a hot runner vent, it means internal condensation, or a possible water pipe break. Dampness can trigger a fatal short circuit to the heater. The chances of this condensation occurring increase if the machine is not running all year round and needs to be switched off at night or at weekends.

2. Remember to remind the operator not to "clean out" the hot nozzle tip at the sprues. If the operator happens to see a small piece of stainless steel at the mould spout, it could be a spot spout assembly. "Cleaning" this seemingly obstructive object can often ruin the hot nozzle head. In order not to damage the hot nozzle, please check the type of nozzle on the hot runner system before taking action and ensure that all operators are trained to recognise the different types of nozzles they are dealing with.

3. Slip stop. For machines that run all year round, this should be done weekly. And the end of the year is a good time to give these parts a routine lubrication service.

4. Interactively calibrate the resistance value of the heater. You should have measured the resistance value of the heater when you first started using it, and the end of the year is the time to measure it again and compare it. If the resistance value fluctuates by ±10%, it is time to consider replacing the heater to ensure that it does not fail at a critical point in the production process. If the initial resistance value has never been measured, measure it once and use the resulting value as reference data for future checks on that heater.

5. Look for signs of wear between the guide pillar and guide bush. Look for marks such as scratches or scuffs, this type of mould fitting wear is caused by a lack of lubrication. If the marks have only just appeared, then you can still extend the life of the guide pillar and guide bush by adding lubricant to them. If the wear is already severe, then it is time to replace the parts with new ones. Otherwise, the cavity and core parts may not fit together well, resulting in inconsistent thinness of the part cavity walls.

6. Check the water flow. Connect a hose at the water outlet and let the water stay in the barrel through the hose. If the water flowing out is not clear or has a colour, rust may be present, while a poor water flow means a blockage somewhere. If you find these problems, drill through all the hoses again (or take whatever method you most often use to clean them) to ensure a clear flow. Improving your plant's water treatment system can prevent future problems caused by rust and blockages.

7. Clean the thimbles. After a year, the ejector pin can become dirty due to gas hoarding and film-like impurities. A good cleaning with a mould cleaner is recommended every 6 to 12 months. After cleaning, apply a layer of lubricant to the ejector pin to prevent scuffing or breakage.

8. Look for breaks in the radius area of the hot nozzle. Fractures are caused by loose hardened pieces of plastic left in the hot nozzle of the machine being subjected to gripping forces from the barrel assembly during forward injection. The problem can also be caused by a misalignment of the centre line. Both of these possibilities are to be considered when finding a break. If the damage sustained is so severe that a petal-like leak cannot be prevented, the sprue sleeve should be replaced promptly.