Hot melt glue pot has burnt particles, don’t rush to change the glue: check from insulation to cleaning

hot melt adhesiveWhen the glue pot has burnt particles, uneven glue dispensing, or impurities in the glue line, simply replacing the glue may not solve the problem. This article sorts out the troubleshooting sequence according to “glue pot status, temperature setting, shutdown habits, and glue supply path” to help reduce downtime and material waste in packaging, binding, and graphic processing sites.

Core Keywords
Hot melt adhesive pellets, hot melt adhesive pot cleaning, EVA hot melt adhesive, hot melt adhesive carbonization, hot melt adhesive equipment maintenance

The black spots and burnt particles in the glue pot are often only discovered during busy production: the nozzle begins to break the glue, impurities are trapped in the glue line, and dirty spots appear on the edges of the finished product. The first reaction on site is usually ‘there is a problem with this batch of glue’, but before judging the raw materials, the glue pot and glue supply system should be checked first.

The formation of coke particles is usually related to long-term high-temperature insulation, repeated heating of residual glue in the pot, temperature control deviation, or accumulation of glue in equipment dead corners. Especially after changing orders, shutting down, and keeping warm at night, old glue residue remains at the edges or corners, which is more likely to affect the glue release state during the next heating up.

You can process it in the following order:

Check the inner wall and dead corners of the glue pot.
Observe whether there are any color abnormalities or hardening residues around the pot wall, filter screen, and pump body. Don’t just scoop away the surface glue, the accumulation of glue at the bottom and edges is often the source of the problem.

Verify the actual temperature.
The temperature displayed on the control panel may not necessarily be equal to the actual temperature of the glue pot, hose, or nozzle. If a certain period of time is consistently high and the adhesive stays in that position for too long, there may be a change in state. The temperature zone should be calibrated based on the equipment situation, and excessive insulation should be avoided when there is no production.

Looking back at the habits of shutdown and rubber replacement.
Frequent start-up and shutdown, mixing of different types of adhesive, and failure to clean old adhesive according to equipment requirements all increase the risk of residual adhesive. Before changing the adhesive, compatibility should be confirmed and necessary cleaning and cleaning operations should be arranged.

Check the filter screen, nozzle, and conveying pathway.
Even if the glue pot looks normal, clogged filter screens, nozzle glue accumulation, or abnormal local temperature of the rubber hose can still cause impurities and broken glue problems to concentrate on the finished product end.

After processing the equipment status, use the same batch of adhesive to conduct a small-scale test machine to observe the uniformity of the adhesive, the appearance of the adhesive line, and the bonding status. This can avoid repeatedly replacing raw materials when equipment problems have not been resolved.

Sunlife can assist in determining the direction of EVA hot melt adhesive adaptation based on the customer’s equipment type, adhesive application scenario, and abnormal performance, and provide sample testing and technical support; For continuous production demand, stable supply and adhesive replacement can also be coordinated.

FAQ

Q: After discovering burnt particles, is it necessary to immediately empty the entire pot of glue?
A: It should be judged based on the number of coke particles, residual glue status, and equipment conditions. If there are obvious carbonization residues or affected glue release, it is recommended to clean the glue pot and pathway according to equipment specifications before resuming production.

Q: Will the higher the temperature set, the more stable the adhesive will be?
A: Not necessarily. The temperature needs to be matched with the type of adhesive, equipment, and production cycle. Long term excessive insulation may increase the risk of residual adhesive state changes.

Q: After changing a batch of glue, the burnt particles appeared. Can we directly determine that it is a problem with the glue?
A: I can’t. The cleaning record, residual old glue, temperature zone setting, and filter status should be checked simultaneously before retesting the sample.