Category: Resources

Before troubleshooting a Hot Melt System, refer to the safety procedures in your OEM manual for that machine.

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Problem	Possible Cause	Suggested Solution
Stringing	Application temp. too low	Raise application temp. DO NOT exceed recommended application temp.
	Viscosity of adhesives is HIGH	Raise application temp. DO NOT exceed recommended application temp.
	Substrate is too far from applicator tip.	Position substrate closer to tip.
	Substrate temp. is too cold	Pre-warm substrate to increase surface temperature.
	Poor nozzle shut off	Clean Nozzle and repair. If problem persists, contact equipment manufacturer.
Charring/Gelling in Reservoir	Reservoir temp. too high	Lower reservoir temperature
	Faulty heating control	Check control and replace
	Surface oxidation	Maintain level of adhesive in reservoir. Keep reservoir covered; with some adhesives, nitrogen blanket may be necessary.
Dripping Nozzle	Worn needle or seat	Replace
	Nozzle dirty	Clean or replace
Air in Adhesive at Applicator Tip	Extrusion head faulty	Consult with the manufacturer for a recommendation
	Reservoir is out of adhesive.	Bleed lines and refill reservoir. Reset or replace valve.
Poor Adhesion	Adhesive bond shows that the glue film is mostly on one surface which is caused by improper penetration of the secondary surface.	A) Apply heavier glue film and/or apply adhesive hotter. Sometimes both approaches are necessary. B) In the case of very conductive surfaces (metals) the substrate may have to be preheated to assure proper penetration of the secondary substrate.
	Bond failure shows adhesive on both surfaces with leggy strains.Usually caused by disturbing the Bond during the setting stage.	A) Check compression to assure that there is no shifting during adhesive set up. B) Apply less adhesive. C) Lower adhesive Temperature.
	Poor penetration of substrate coating	A) Apply adhesive hotter. B) Combine substrates quicker. C) Lower adhesive temperature.
	Glossy adhesive surface usually caused by poor contact with the secondary substrate. Temperature too low for proper wet out.	A) Adjust compression to assure intimate contact of substrates. B) Increase adhesive temperature.
Substrates Popping open	Hot melt is not cooling rapidly enough	A) Lower application temperature. B) Decrease amount of adhesive applied.
	Substrate is too hot to achieve proper cooling of adhesive	Cool substrates to room temperature if possible.

For more detailed hot melt trouble shooting tips, or to speak with a technical representative about your application, and to request samples, please call us at 1-800-249-0337 or email us at [email protected]

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