Problem 1: Adhesive Stringing
Symptom: Thin threads of adhesive stretch between the applicator and the substrate, creating mess and potential quality issues.
Causes: Application temperature too high, adhesive viscosity too low, or excessive applicator distance from the substrate.
Solutions: Reduce application temperature by 10-20°C. Switch to a higher-viscosity or "short-set" formulation designed to minimize stringing. Reduce the gap between the applicator head and the substrate. Consider using a spiral spray pattern instead of a straight stream.
Problem 2: Adhesive Charring
Symptom: Dark, carbonized deposits build up in the melt tank or on the applicator nozzle, affecting adhesive flow and bond quality.
Causes: Tank temperature too high, adhesive sitting in the tank for too long, or contaminated adhesive.
Solutions: Verify tank temperature with a calibrated thermometer (do not rely solely on the machine display). Clean the tank every 100-200 operating hours. Use fresh adhesive and avoid mixing different adhesive types. Consider adhesives with higher thermal stability for high-temperature applications.
Problem 3: Poor Adhesion / Bond Failure
Symptom: The adhesive does not stick properly, or the bond fails shortly after application.
Causes: Wrong adhesive for the substrate, surface contamination, insufficient adhesive application, or application temperature incorrect.
Solutions: Clean substrates to remove dust, oil, and release agents. Verify that the adhesive is compatible with your substrate materials. Increase application temperature by 10°C to improve flow and wet-out. Apply more adhesive or increase the bond area. Check that the substrates are being pressed together firmly during the set time.
Problem 4: Adhesive Bleed-Through
Symptom: Adhesive soaks through thin substrates (paper, fabric) and becomes visible on the other side.
Causes: Adhesive viscosity too low, application temperature too high, or too much adhesive applied.
Solutions: Use a higher-viscosity formulation that stays on the surface. Reduce application temperature. Reduce the amount of adhesive applied. Consider using a pre-coated film instead of bulk adhesive for uniform coverage without bleed-through.
Problem 5: Inconsistent Bond Quality
Symptom: Some products bond well while others fail, even on the same production line.
Causes: Temperature fluctuations, inconsistent adhesive application, variable substrate quality, or environmental factors (humidity, drafts).
Solutions: Install temperature monitoring and alarms on your melt system. Calibrate applicator systems regularly. Store substrates in a controlled environment. Shield the application area from drafts and temperature variations. Implement regular quality checks with peel and shear tests.
Need Technical Support?
If you are experiencing adhesive issues that these troubleshooting tips cannot resolve, our technical team is here to help. We can analyze your specific application, recommend the right adhesive formulation, and provide on-site technical support. Contact us for assistance.