1. Quick diagnostic process
When the heat sealing temperature of the packaging machine fluctuates abnormally, it is recommended to follow the steps below to troubleshoot:
Check the temperature sensor and controller
Observe whether the temperature display value jumps frequently and confirm whether the thermocouple wiring is loose or oxidized.
Use a multimeter to detect the thermocouple resistance (normal is about 8Ω). If abnormal, replace the sensor.
Test the heating element
After disconnecting the power supply, measure the resistance of the heating tube. If it is open or abnormal, it needs to be replaced.
Check whether the solid-state relay is normally switched on and off. If the contact is oxidized, it needs to be polished or replaced.
Evaluate environmental interference
Monitor the temperature and humidity of the workshop. If the ambient temperature fluctuates >5¡æ or the humidity is >70%, air conditioning or dehumidification equipment needs to be installed.
2. Common troubleshooting solutions
1. Unstable temperature display
Cause : Carbon deposition on the collector ring, poor contact of the thermocouple or aging of the carbon brush holder
Solution:
Use sandpaper to clean the carbon deposits on the collector ring and fix the wiring.
Replace the brush holder with loose springs to ensure close contact of the thermocouple.
2. The heat sealer does not heat up.
Reason: The heating tube is damaged, the circuit breaker is tripped, or the control system fails.
Solution:
Replace the disconnected heating tube and reset the circuit breaker.
Check the PLC control signal and repair the short-circuited or loose control line.
3. The seal is uneven/unsealed.
Reason: The sealing material has poor thermal conductivity, uneven pressure, or impurities are attached to the heating cloth.
Solution:
Use packaging materials with consistent thermal permeability.
Adjust the pressure spring of the heat sealing knife and clean the residue on the surface of the heating cloth.
III. Preventive maintenance recommendations
Daily maintenance
Clean the dust on the collector ring, brush holder and heating element surface every week.
Calibrate the temperature sensor every month to ensure that the difference between the displayed value and the actual temperature is ≤3¡æ. Long-term optimization
Upgrade the intelligent temperature control module and integrate the ambient temperature and humidity compensation function.
Install an overheat protection device for the packaging machine, and automatically cut off the power when the temperature exceeds the standard.
IV. Typical case reference
When a food company used the ply-pack packaging machine, the heat sealing temperature fluctuated due to excessive humidity in the workshop:
Problem: The humidity in summer reached 85%, and the horizontal sealing temperature jumped ±15¡æ.
Solution: Install a professional dehumidifier. After the humidity stabilized to 60%, the temperature fluctuation dropped to ±2¡æ.
This solution is based on the summary of the ten-year service experience of the ply-pack packaging machine and is suitable for a full range of equipment such as liquid packaging machines and vertical packaging machines. Through systematic troubleshooting and preventive maintenance, 90% of unplanned downtime can be reduced to ensure production continuity.
