Analysis of common problems in the paste box process

1, adhesive fastness is not high, carton degumming. Degumming refers to the cracking of sticky joints due to insufficient adhesiveness. The main reasons are summarized as follows:

(1) Adhesives have insufficient viscosity or insufficient glue.

(2) The adhesive and carton material do not match.

(3) The sticky part of the carton is subjected to surface treatment such as coating and glossing. The adhesive is difficult to penetrate through the surface layer and penetrates into the paper.

(4) The pressure after folding and gluing is insufficient, and the pressing time is not long enough, which is not good for sticking.

For the above problems caused by adhesives, we should choose adhesives suitable for carton materials, and the selection and use of adhesives are also very particular. First of all, we cannot mistakenly believe that the higher the viscosity of the adhesive, the better the paste box effect. With high viscosity, the adhesive strength also becomes higher, and the wrinkling rate also increases. The recommended viscosity of the adhesive is 500 to 1000 cps in a case where the automatic folder gluer rolls at a high speed of 112 rotations per minute.

Second, adhesives have stronger bonding strength. Because the instantaneous pressure in the molding part of the automatic folder-gluer is not very large, and during the high-speed operation that produces 30-40 cartons per minute, the pressing time is not long, and the adhesive with strong adhesive strength is even lighter. With pressure, the carton can also be firmly bonded.

In addition, the ambient temperature of the gluing workshop will also have a certain impact on the adhesive. If the temperature of the gluing workshop is too low, the adhesive will immediately solidify, affecting the fastness of the adhesive, and even if the amount of gluing is large, it will not work. Of course, the less the amount of glue applied is, the more sensitive it is to the room temperature. Therefore, the temperature of the gluing workshop should be maintained at 20°C or more during the winter. Conditions can be adjusted with an air conditioner. In the paste-box workshop, large-scale and easy-to-read thermometers are also installed to check and control the operating environment at any time. For a good paste product, it should be dried at room temperature and then leave the factory. In winter, avoid dripping and rushing delivery.

There are four ways to solve the problem of unstuck in the case of coated and coated cartons:

First, when the die is cut, a needle knife is placed at the sticky mouth to puncture the sticky surface to facilitate the penetration of the adhesive.
Secondly, the surface of the sticky mouth is worn out with the edging device attached to the automatic folder gluer to facilitate the penetration of the adhesive.
Thirdly, the hot melt adhesive is sprayed on the sticky portion to melt the sticky surface material at a high temperature to improve the fastness of the sticking box.
Fourth, in the box-type design before printing, it is possible to leave a glue-applied portion on the edge of the film to be coated and polished in advance.

For the inconsistent phenomenon caused by insufficient pressure, the pressure of the pressing part of the folder-gluer can be increased, the pressing time can be prolonged, or the adhesive with strong adhesive force can be replaced.

2, carton deformation

There are mainly three kinds of causes for deformation of the carton:

(1) Some die-cuts are hand-made, often resulting in inconsistent carton sizes due to inaccurate precision, and distorting the carton when gluing.

(2) The adhesive has a low concentration and a large amount of moisture, resulting in moisture absorption and deformation of the paperboard, and the carton is not evenly formed after molding.

(3) The folder gluer itself is not adjusted well.

To solve this problem, as long as the quality of die-cutting is stable, choose a suitable concentration of adhesive and adjust the folder-gluer to solve it.

3, cartons sticky skew

There are mainly three kinds of causes for skewing of the produced trays:

(1) The pressure groove of the indentation line is too wide and the indentation pressure is not enough, so that the extruding marks are not full, and the folds cannot be accurately folded in accordance with the indentation line.

(2) The improper adjustment of the folding transmission, the conveyance speeds of the left and right sides of the cassette are inconsistent, and the sticky mouth is skewed.

(3) The folding bar is not installed properly.

Solution: Reduce the width of the indentation line and increase the indentation pressure; adjust the folding transmission so that the feeding speeds of the left and right sides of the carton are the same; reinstall the folding bar.

4, sticky mouth alignment is not allowed

Viscous misalignment is misalignment, and misplaced cartons are not well formed. This phenomenon is usually caused by inaccurate adjustment of the machine. Further, it is mainly due to the fact that the operator's knowledge of the box type and the folder gluer has not affected its operation level. Therefore, strengthening the training of operators, improving their operating skills and their understanding of complex box types can effectively avoid the problem of inaccurate sticking.

5, sticky mouth overflow plastic

Overfill refers to excessive adhesive flow out of the sticky mouth. This phenomenon is mainly caused by misalignment of the adhesive and excess amount of adhesive. By grinding the sticky mouth and reducing the amount of glue can effectively reduce the occurrence of overflow phenomenon.