Daily maintenance and care of PVC injection molding machines, how to avoid the decomposition of barrel residues during shutdown?

1. Daily maintenance of PVC injection molding machines
Temperature control and barrel cleaning
Precise temperature control: The processing temperature range of PVC is small, and the segmented temperature of the barrel needs to be strictly controlled to avoid local overheating and degradation. The PID temperature control system needs to be calibrated regularly to ensure that the deviation is within the controllable range.
Special screw and barrel: PVC is easy to release HCl gas. It is recommended to use corrosion-resistant double alloy screws and nitrided barrels to avoid corrosion of ordinary screws.
Foreign body protection: The hopper is equipped with a magnetic frame to prevent metal impurities from entering the barrel and causing screw wear; HDPE or HIPS can be used to clean the barrel after use to avoid carbonization of PVC residues.
Lubrication system management: Regularly check the oil level of the electric lubrication pump and use acid-resistant lithium-based grease to reduce the risk of failure caused by residue decomposition.
Cooling water treatment: Regularly clean the scale in the mold and hydraulic oil cooler of the PVC injection molding machine. When shutting down, the water channel needs to be blown dry to prevent rust or cracking.

2. Measures to avoid decomposition of barrel residues during shutdown
Complete material cleaning and material replacement
Cleaning process: Replace the residues in the barrel with neutral plastics such as PP or PS before shutdown to avoid HCl gas corrosion of equipment at high temperatures.
Screw retraction: After clearing the material, the screw needs to be adjusted to the rear end to prevent residual PVC from being retained in the heating zone and causing carbonization.
Low temperature insulation: Before turning off the main power supply, set the barrel temperature to 100-120℃ for insulation to avoid a sudden drop in the temperature in the barrel and cause PVC decomposition.
Antifreeze drainage: Close the cooling water valve, disassemble and blow dry the residual moisture inside the mold and oil cooler to prevent the pipeline from freezing and cracking when not in use.