Applicable Systems
RX
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
- Step 1: Measure the seal jaw temperature with an independent surface thermometer
Compare to the controller setpoint; if below, investigate the heater and sensor - Step 2: Check the heater cartridge resistance with a multimeter
Replace if open or more than 10% different from the rated resistance - Step 3: Verify the thermocouple connection and resistance
Replace if open or intermittent when the wire is flexed - Step 4: Inspect the Teflon tape on the seal jaw and replace if worn or burnt
Clean the jaw surface before applying new tape - 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