1. The problem of glue: hot melt glue made of inferior materials has low purity or unstable softening point.
2. The problem of glue storage; it is contaminated during production or transportation, mixed with dust, impurities, etc.;
3. The glue machine problem: the glue tank is generally coated with Teflon coating, and the coating of the poor quality glue machine is uneven, resulting in uneven temperature control;
4. Operational problems; the operator did not work according to the specifications, in order to achieve rapid operation, the temperature was raised too high, too much glue, etc., which may cause the unused hot melt glue to be repeatedly heated;
5. Maintenance problems; the glue machine is not cleaned and maintained regularly, causing the residual glue to be repeatedly heated and carbonized;
