Maximising Uptime: Best Practices for Maintenance of Bag Sealers & Shrink Tunnels

When it comes to packaging machinery, reliability is everything. Every minute of downtime can slow production, increase waste, and affect delivery schedules. For businesses using bag sealers and shrink tunnels, a simple maintenance plan can make the difference between consistent output and costly interruptions. At Sontex (Machinery) Ltd, we’ve been supporting UK manufacturers for over 60 years, and we know first-hand that proactive maintenance is the key to getting the most out of your machinery. Here are our top tips for keeping your packaging line running at its best. ⚙️ 1. Establish a Routine Maintenance Schedule It might sound obvious, but regular maintenance is often overlooked in busy production environments. Every machine—whether it’s a manual bag sealer or an automatic shrink tunnel—has moving parts that need care. Create a simple maintenance log that includes:
  • Daily checks: clean sealing bars, remove plastic residue, check for air leaks or blockages.
  • Weekly checks: inspect belts, heaters, fans, and temperature sensors.
  • Monthly checks: check electrical connections, motor performance, and replace any worn Teflon tape or sealing wires.
Scheduling small, regular tasks helps prevent unexpected breakdowns that can stop production completely. 🧼 2. Keep It Clean Packaging environments can generate a surprising amount of dust, debris, and film residue—especially around shrink tunnels where plastic fragments accumulate. To maintain efficiency:
  • Wipe down sealing jaws after every shift.
  • Use a soft brush or vacuum to remove dust and fragments from the tunnel conveyor.
  • Avoid harsh cleaning chemicals on Teflon-coated surfaces; a mild detergent and lint-free cloth work best.
  • Make sure cooling fans and vents are kept clear—blocked airflow can cause the tunnel to overheat or deliver uneven shrink results.
A clean machine not only runs better but also extends the life of heaters, belts, and sensors. 🔧 3. Check Alignment and Pressure Regularly For bag sealers, poor sealing performance is often caused by uneven pressure or misalignment of the sealing jaws. Check that:
  • The sealing bar closes evenly across the entire width.
  • There are no gaps or cold spots in the seal.
  • Teflon tape is smooth, without creases or burns.
With shrink tunnels, ensure the conveyor belt is correctly tensioned and centred. Misalignment can cause products to skew or snag as they pass through the tunnel, reducing both speed and finish quality. 🔌 4. Monitor Electrical and Heating Components Bag sealers and shrink tunnels rely heavily on precise heat control. Faulty thermocouples or failing elements can lead to inconsistent sealing or film scorching. Watch for:
  • Fluctuating seal temperatures (indicating a failing thermostat).
  • Slow heat-up times or cold spots in the tunnel.
  • Tripped fuses or burnt smells from wiring (a sign of wear or overloading).
If you notice any of these signs, isolate the power supply immediately and have a qualified technician check the components. At Sontex, our service engineers can quickly test and replace heating elements, thermostats, and control boards to get you back up and running. 🪛 5. Replace Worn Parts Before They Fail Certain parts have predictable lifespans—such as sealing wires, belts, and Teflon tape. Keeping spares on site means you can replace them before a breakdown occurs. Recommended spare parts to hold in stock:
  • Sealing wire kits and Teflon covers
  • Conveyor belts and drive chains
  • Heating elements and sensors
  • Motor brushes and fuses
Sontex can supply genuine OEM spares for all major brands, ensuring compatibility and long-term reliability. 🧠 6. Train Operators Properly Operator error is one of the leading causes of machine faults. Make sure your team understands:
  • Correct warm-up and cool-down procedures.
  • How to load products safely into the tunnel.
  • What not to touch or adjust while the machine is in operation.
A short training session can save hours of lost production time later on. 🔄 7. Schedule Professional Servicing Even with good daily maintenance, an annual or biannual professional service is essential. A qualified Sontex engineer can:
  • Check for hidden wear inside heaters and control panels.
  • Recalibrate temperature and speed settings.
  • Replace perishable seals and gaskets.
  • Perform a full safety inspection and PAT test.
Regular servicing extends machine life, maintains warranty compliance, and ensures your packaging remains consistent and compliant with safety standards. ✅ Keep Your Production Flowing with Sontex By adopting these maintenance best practices, you’ll reduce downtime, improve packaging consistency, and extend the lifespan of your machinery. At Sontex (Machinery) Ltd, we supply, install, and service a full range of bag sealers, shrink tunnels, sleeve sealers, and pallet wrapping machines across the UK. Whether you need spare parts, training, or a scheduled maintenance visit, our expert team is here to help keep your line running smoothly. Contact Sontex today for technical support or to arrange a service visit from one of our engineers.