How to maintain the screw of the injection molding machine?

The screw is an important part of the injection molding machine. The screw of the injection molding machine works under high temperature, high pressure, high mechanical torque and high friction environment for a long time, and loss is inevitable. Even if the screw of the injection molding machine has undergone various surface treatments, from quenching to nitriding, boronizing, spraying, and double alloy spraying, it is still necessary to pay attention to daily maintenance.

The same injection molding machine screw can be used in some factories for 8 years, and some can only be used for 2 months. The key to the life of the injection molding machine screw is use and maintenance, so this article will share some maintenance knowledge about the injection molding machine screw:

1) When the injection molding machine is started, the injection molding must be fully preheated. After the barrel reaches the preset temperature, keep the temperature for 15 minutes below Φ60mm. After the above 30 minutes, start the motor and start the screw related actions.

2) Material and screw must match. Especially corrosive materials and hard materials, such as PVC, flame-retardant materials, and glass fiber-added materials should use professional screws instead of ordinary screws.

3) If the corrosive materials used for ordinary machines must be cleaned and replaced with stable materials such as HDPE, HIPS, etc. immediately after use.

4) If glass fiber material is occasionally used in ordinary machines, be sure to use high material temperature, low screw speed, and low back pressure.

5) Regardless of the material, try not to produce at the lower temperature limit. For example, PC material can be produced at 250 degrees, and ABS can barely be made at 185 degrees, but it is not good for the screw because it requires large torque and severe wear. At the same time, if you must use the lower limit problem, use a low screw speed.

6) If the machine stops for more than half an hour each time, close the blanking port, clean the material in the barrel, and set up heat preservation.

7) Avoid foreign matter falling into the barrel and damage the screw and barrel. Prevent metal fragments and debris from falling into the hopper. If processing recycled materials, a magnetic hopper must be added to prevent iron filings from entering the hopper.

8) When using anti-salivation, make sure that the plastic in the barrel is completely melted to avoid damage to the transmission system parts when the screw is retracted.

9) Avoid the phenomenon of screw idling and slipping.

10) When using new plastic, the remaining material in the barrel should be cleaned. When using POM, PVC, PA+GF and other materials, minimize the degradation of the raw materials, and rinse them with ABS and other nozzle materials in time after shutdown.

11) Avoid mixing POM and PVC into the barrel at the same time, which will react at the melting temperature and cause serious industrial accidents.

12) When the temperature of the molten plastic is normal but black spots or discoloration of the molten plastic are constantly found, check whether the rubber screw non-return ring seat (apron, meson) is damaged.