In the daily operation of a flow packaging machine, the stability of the temperature control system directly affects sealing quality and packaging efficiency. Once the temperature controller malfunctions and causes disorder in temperature regulation, the consequences may range from weak sealing and poor appearance to burnt film, machine downtime, or even damage to heating components. Therefore, identifying the cause and taking timely action is essential.
I. Symptoms of the Malfunction**
When the temperature controller becomes chaotic, the following issues commonly occur:
1. **Temperature fluctuates drastically**, unable to stabilize near the set value.
2. **Abnormal display**, such as jumping numbers, no display, or error codes.
3. **Heating becomes uncontrolled**, continuously heating or not heating at all.
4. **Sealing quality deteriorates**, causing burnt edges, weak sealing, or uneven sealing lines.
5. **Uneven temperature between heating zones**, such as upper/lower or left/right plates.
II. Main Causes of the Malfunction
1. **Internal failure of the temperature controller**
Long-term high temperature or component aging may cause logic errors or display problems.
2. **Faulty thermocouple (temperature sensor)**
Aging, open circuits, short circuits, or poor contact can lead to incorrect feedback signals.
3. **Solid-state relay (SSR) or relay malfunction**
A defective SSR may remain permanently ON or OFF, causing continuous heating or no heating.
4. **Heating wire or heating plate issues**
Broken heating wires, loose connections, or abnormal resistance can cause unstable temperature.
5. **Unstable power supply**
Voltage fluctuations in the plant can affect controller output and heating performance.
6. **Loose or aged electrical wiring**
Long-term heat exposure or vibration may cause poor contact and signal disorder.
III. Solutions and Troubleshooting Steps
1. Inspect and reset the temperature controller
* Turn off power and restart the machine.
* Verify that parameters are not accidentally changed.
* If the panel is unresponsive or abnormal, replace the temperature controller.
2. Check the condition of the thermocouple
* Ensure it is firmly fixed and not detached or burnt.
* Measure resistance to check for abnormalities.
* Replace with the same model when aging or damaged (commonly K-type).
3. Test the solid-state relay (SSR)
* Observe whether the indicator light reacts with controller output.
* Replace SSR immediately if heating never stops or never starts.
4. Inspect heating wire and heating plate
* Test continuity of heating wire.
* Clean oxidation and tighten terminal screws.
* Replace heating wire if partially burnt.
5. Stabilize power supply
* Consider using a voltage stabilizer.
* Check whether internal wiring is aged or damaged.
6. Check all wiring and electrical components
* Tighten all terminal connections.
* Clean dust inside the control box to prevent interference.
* Re-crimp or replace wiring if poor contact is detected.
IV. Preventive Measures
1. **Regularly inspect heating zones**, including terminals and thermocouple fixation.
2. **Keep the control box ventilated**, reducing component aging.
3. **Record abnormal temperature behaviors** for early detection.
4. **Use high-quality consumables**, such as reliable thermocouples and SSRs.
V. Conclusion
A malfunctioning temperature controller on a flow packaging machine directly impacts product quality and production efficiency. Through systematic inspection and timely replacement of key components, the machine can quickly return to normal operation. Proper routine maintenance can significantly extend equipment lifespan and reduce losses caused by temperature disorder.
