Applicable Systems
TFS

Symptoms

The packaging machine seal jaw temperature has dropped below the minimum required for the film type. The sealed packages fail the peel test.

Possible Causes

  • Seal jaw heater cartridge open-circuited or partially failed
  • Seal jaw thermocouple disconnected or giving incorrect reading
  • Seal jaw Teflon tape worn, causing poor heat transfer to the film
  • Seal jaw pressure insufficient due to worn springs or air cylinder leak

Troubleshooting Steps

  1. Step 1: Measure the seal jaw temperature with an independent surface thermometer
    Compare to the controller setpoint; if below, investigate the heater and sensor
  2. Step 2: Check the heater cartridge resistance with a multimeter
    Replace if open or more than 10% different from the rated resistance
  3. Step 3: Verify the thermocouple connection and resistance
    Replace if open or intermittent when the wire is flexed
  4. Step 4: Inspect the Teflon tape on the seal jaw and replace if worn or burnt
    Clean the jaw surface before applying new tape
  5. Step 5: Check the air cylinder pressure and verify the seal jaw closes with adequate force
    Adjust the pressure regulator if below specification

How to Reset

Reset: After heater or sensor replacement, recalibrate the temperature controller and verify seal quality with a peel test.

Common Replacement Parts

  • Heater cartridge: 240V, 250W, cartridge type (Match to seal jaw dimensions)
  • Thermocouple: Type J or K, exposed junction (Match to controller input type)
  • Teflon tape: PTFE, 0.08mm, adhesive-backed (Replace weekly in high-volume production)

Frequently Asked Questions

  • Q: What temperature do I need for sealing?

    For PE film: 140-180C. For PP film: 160-200C. For PET/PE laminate: 150-190C. Always check the film specification.

  • Q: How do I test seal quality?

    Cut a 25mm strip from the seal, peel it apart in a tensile tester, and record the peel force. Minimum acceptable peel force: 3-5 N per 25mm for most applications.

  • Q: How often should I replace Teflon tape?

    Daily in continuous production, or when visible wear or burning appears. Worn tape causes uneven heating and film sticking.

Source: OEM Operation Manual

Category: Packaging