Short answer: A hot melt unit malfunction can usually be resolved by checking and cleaning the temperature settings, nozzles, and modules. The problem is often caused by the adhesive temperature being too low or too high, contaminated parts, or a defective shut-off spring.
Hot melt adhesive units require specific knowledge due to the high temperatures (180°C) and high pressures (30 to 100 BAR). Therefore, always have maintenance and malfunctions resolved by an experienced technician!
Common causes and solutions for hot melt malfunctions
1. Problems with the nozzle
- Dyeing or thread pulling
- Glue temperature too low → set the gun zone higher.
- Bring the nozzle closer to the product.
- Module does not close properly due to contamination or weak spring → clean and readjust the spring.
- Hot melt too thin for the nozzle → use a thicker adhesive or lower the temperature.
- Blocked nozzles
- Often caused by contamination or burnt adhesive residues.
- Solution: regular cleaning and use of filters.
2. Temperature settings
- Excessive temperature → adhesive may burn and cause blockages.
- Temperature too low → adhesive does not flow properly and causes stringing.
- Action: Check the set zones and adjust according to the adhesive specifications.
3. Mechanical faults
- Worn or contaminated shut-off springs and modules.
- Solution: clean or replace parts.
- Preventive maintenance prevents unexpected downtime.
Checklist for resolving hot melt malfunctions
1. Safety first
- Switch off the machine and allow the unit to cool down.
- Wear heat-resistant gloves and safety goggles.
2. Basic check
- Check whether the unit is receiving power.
- Check that all zones (tank, hose, nozzle) reach the correct temperature.
- Compare the set temperature with the specifications of the adhesive used.
3. Adhesive supply
- Check that there is sufficient hot melt in the tank.
- Check that the adhesive has not been burnt or discoloured (excessive temperature).
- Only fill with the correct type of hot melt (avoid mixing different types).
4. Hoses and guns
- Inspect hoses for kinks or damage.
- Check that the gun module closes properly.
- Clean or replace clogged nozzles.
5. Mechanical components
- Check the module's sealing spring (for wear or contamination).
- Check whether the filters are clean.
- Replace worn parts preventively.
6. Electronics and sensors
- Check temperature sensors and cables.
- Check whether there are any error codes on the display and make a note of them.
- Reset the unit if possible.
7. Test after repair
- Switch the unit back on and allow it to reach the correct temperature.
- Test an adhesive application on a sample piece.
- Ensure that the adhesive is applied evenly and without streaks.
4. Electrical faults
- Faulty sensors or heating elements.
- Solution: have this checked by a specialised service provider (e.g. Nordson, Robatech, Dynatec service).
Practical tips
- Always check first: voltage, temperature settings, and adhesive type.
- Clean regularly: nozzles, filters, and modules to prevent blockages.
- Preventive maintenance: plan inspections to avoid downtime.
- Seeking assistance: In the event of complex malfunctions, a service company such as Hotmelt Service or VDL Distritech can provide 24/7 support.
Please note
- Always work safely: hot melt units operate at high temperatures and pressures.
- Switch off the machine and allow it to cool down before cleaning or replacing any parts.
- Consult the manual for your specific brand (Nordson, Robatech, Dynatec, etc.) for exact settings.
At If you experience a malfunction with your hot melt equipment, you can contact us 24/7. Please contact hotmeltservice!
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