What are the common faults of blow molding machines? How to quickly diagnose and solve them?

Common faults of blow molding equipment include mechanical faults, electrical faults, hydraulic faults and molding faults. The following are some quick diagnosis and solutions for common faults:
Mechanical faults
Abnormal screw rotation
Fault description: The screw is stuck, makes abnormal noises or has unstable speed when rotating.
Diagnostic method: Check whether there is foreign matter stuck between the screw and the barrel, whether the screw bearing is damaged, and whether the drive motor and transmission device are working properly.
Solution: Clean foreign matter between the screw and the barrel, replace damaged bearings, and repair or replace faulty drive motors and transmission devices.
Mold opening and closing mechanism fault
Fault description: The mold opening and closing action is not smooth, the speed is too slow or the mold cannot be opened and closed normally.
Diagnostic method: Check whether the mold opening and closing cylinder is leaking, whether the hydraulic oil is sufficient, whether the guide column and guide sleeve of the mold are worn, and whether the limit switch of the mold opening and closing is normal.
Solution: Repair the cylinder leakage problem, add hydraulic oil, replace the worn guide column and guide sleeve, and adjust or replace the limit switch.
Electrical failure
Temperature control failure
Fault description: The temperature of the barrel or mold cannot be stabilized at the set value, and the temperature is too high or too low.
Diagnostic method: Check whether the temperature sensor is damaged, whether the heating element is working properly, and whether the temperature controller is faulty.
Solution: Replace the damaged temperature sensor, repair or replace the faulty heating element and temperature controller.
The motor does not start
Fault description: After pressing the start button, the motor does not respond and cannot operate normally.
Diagnostic method: Check whether the power supply is normal, whether the motor wiring is loose or short-circuited, whether the motor overload protection device is tripped, and whether the controller sends a correct start signal.
Solution: Restore normal power supply, repair loose or short-circuited wiring, check and reset the overload protection device, repair or replace the faulty controller.
Hydraulic failure
Insufficient pressure
Fault description: During the operation of the blow molding machine, the hydraulic system cannot provide enough pressure, resulting in weak or incomplete movement.
Diagnostic method: Check whether the hydraulic pump is working properly, whether the hydraulic oil is contaminated or insufficient, whether the overflow valve is faulty, and whether the cylinder is leaking.
Solution: Repair or replace the faulty hydraulic pump, replace the contaminated hydraulic oil and replenish the oil, adjust or replace the overflow valve, and repair the cylinder leakage problem.
Hydraulic oil leakage
Fault description: Hydraulic oil leakage occurs in the pipeline, joints or cylinder of the hydraulic system.
Diagnostic method: By observing the leakage site, check whether the seal is damaged, whether the pipeline is broken or the joint is loose.
Solution: Replace the damaged seal, repair the broken pipeline, and tighten the loose joint.
Molding failure
Uneven wall thickness of the product
Fault description: The wall thickness of the blow molded product is unevenly distributed, some places are thick and some places are thin.
Diagnostic method: Check whether the opening and closing accuracy of the mold is sufficient, whether the blow molding process parameters (such as blowing pressure, blowing time, mold temperature, etc.) are reasonable, and the extrusion uniformity of the parison.
Solution: Adjust the opening and closing accuracy of the mold, optimize the blow molding process parameters, check and adjust the screw and head of the extruder to ensure uniform extrusion of the parison.
There are bubbles or defects on the surface of the product
Fault description: There are bubbles, pits, scratches and other defects on the surface of the product, which affect the product quality.
Diagnostic method: Check whether the raw material is dry enough, whether the mold surface is smooth, whether the blowing system is normal, and whether the molding temperature and pressure are appropriate.
Solution: Dry the raw material fully, polish the mold surface to make it smooth, check and repair the blowing system fault, and adjust the molding temperature and pressure.