The most neglected areas when overhauling injection molds

The maintenance procedures required for each injection molding location depend on the different mold cycle times. Here are some general principles that every mold user can use to keep mold components such as hot runners, heaters, guide pillars, and ejectors operating efficiently in case something unexpected happens.



1. You are looking for warning signs of rust or moisture at the air vents - If you find rust or moisture near the hot runner vents, it means internal condensation or a possible water line break. Humidity can cause a fatal short circuit to the heater. The chances of this condensation increase if the machine is not running year-round, but is shut down at night or on weekends.

2. Remember to remind the operator not to "clean" the hot nozzle tip at the gate - if the operator happens to see a small piece of stainless steel at the mold spout, it may be a spot spout assembly. "Cleaning up" what appears to be an obstruction can often ruin the hot nozzle tip. In order not to destroy the hot nozzle, please check the type of nozzle on the hot runner system before taking action and make sure all operators are trained and can identify all the different types of nozzles they are touching.

3. Slip stop - For machines that run year-round, this should be done once a week.

4. Cross-check the resistance value of the heater - you should have measured the resistance value of the heater when you first started using it, now it is time to measure and compare again. If the resistance value fluctuates up or down by 10%, you should consider replacing the heater to ensure that it does not fail at a critical point in the production process. If you have never measured the initial resistance value, measure it once now and use the resulting value as reference data for future inspections of the heater.



5. Look for signs of wear between the guide pillar and the guide bushing - look for signs of scratching or scuffing, which is due to 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 more lubrication to them. If the wear is already severe, then it is time to replace the parts with new ones. Otherwise, the cavity and the core part may not fit well, resulting in parts with different cavity wall thicknesses.

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 is not clear or has a color, rust may occur, and poor water flow means a blockage somewhere. If you find these problems, drill through all the hoses again to ensure a clear flow (or clean them by whatever method you use most often). Improving your plant's water treatment system can prevent future problems caused by rust and blockages.

7. Clean the ejector pin - After a year, the ejector pin will become dirty due to gas accumulation and film impurities. Zhenye recommends cleaning the ejector every six to twelve months with the mold cleaning agent. After cleaning, apply a layer of lubricant on the ejector pin to prevent scuffing or breakage.

8. Check the radius area of the nozzle for fractures - fractures are caused by loose hardened plastic fragments left in the hot nozzle of the machine during forwarding injection from the clamping force brought by the injection barrel assembly. The problem may also be caused by a misaligned centerline. Both of these possibilities should be considered when finding a break. If the damage is severe enough to prevent a petal leak (a term formerly used by mold users to refer to a plastic leak between the guide bushing and the hot nozzle of the machine), the gate bushing should be replaced.