01
Some experiences about die cutting overflow
1. Shape design of the labels
Alien labels are more likely to produce overglue than square or rectangular labels.
2. Several basic judgment criteria for glue before printing
When the drum nonadhesive material is rolled on the printing press, if there is no drawing or a slight drawing phenomenon between the upper and lower layers, then the material can be judged to be qualified. Of course, you should also understand the temperature and humidity of the site. Sheetfed adhesive material on the paper conveying table of the offset printing machine, if the wire drawing or adhesion between the upper or lower layers occurs, the material can be determined to be unqualified. Because the phenomenon of drawing between the upper and lower layers on the paper stage, will make the dry adhesive material deviation, causing inaccurate overprinting.
3. Overflow of glue after printing and mold cutting
If the end surface of white material adhesion is serious, and there is obvious drawing phenomenon when printing and rolling, then it is likely to be glue around the label after die cutting. It should be noted that the glue is equally related to the displacement and contraction on the bottom paper. During the process of die cutting or after die cutting, the label movement will produce the label unilateral overflow, and the label reduction will cause the label overflow around the label.
4. Control of release and release tension
With the processing materials, the production processes, and the printing presses used differently, it is unrealistic to give a "correct" tension data. The result of tension control is ultimately reflected in the tightness of the volume, and it is the best practice to accept the volume on the most acceptable confirmation with the customer. When printing (including online die cutting), on the basis of not affecting the overprinting accuracy and posterior processing, the smaller the release volume tension control, the better. No matter in which the processing process, the winding tension should be less than the roll tension, and the tension ratio should not be greatly different. When picking up the die cut and dividing the small rolls with both hands, at least push the end up and down with your thumb. If the die-cut and cut into small rolls like a "discus", then the winding tension must be too big.
02
Characteristics of acrylic latex and hot melt latex and the difference in die cutting
Acrylic latex and hot melt adhesive are commonly used in nonadhesive label materials.
It is not difficult to see that the die cutting of hot melt glue is more difficult than acrylic latex. This is because the softer the adhesive, the sharper the die cutting tool is required, so that the die cutting material can be cut in quickly without resistance, so that it will not produce the overflow situation caused by the extrusion of the adhesive layer.
The softer the adhesive, the better the fluidity, and the faster the adhesive returns after die cutting. Therefore, when using the use of hot melt adhesive materials, the shorter the distance between die cutting and waste discharge station is, the better, as far as possible while the cut adhesive layer has not been reflux bonded together as soon as possible.
Because of the low melting point of the hot melt glue (65℃ begins to melt), so controlling the temperature of the die cutting can play a great role. Practice has proved that reducing the temperature of die cutting can effectively prevent the return of hot melt glue, and achieve the purpose of smooth waste discharge (winter die cutting is more smooth than other seasons).
The high initial viscosity of the hot melt adhesive is unfavorable for the die cutting. The high initial viscosity makes the reflux adhesive melt together once encountered (the time is shorter than the acrylic latex), and the drawing phenomenon produced during waste discharge is almost no different from the drawing phenomenon produced without cutting off the adhesive layer.The initial high viscosity of the hot melt adhesive makes the die cutter firmly stick to the adhesive when cutting off the adhesive layer, and a lot of adhesive gradually accumulates on the tool surface. If the adhesive accumulated on the tool is not cleaned up in time, it will be continuously transferred to the label in the process of repeated die-cutting, causing the glue overflow. Therefore, the die-cut hot melt glue tool needs to be coated with fluorine, and the adhesive on the tool also needs to be cleaned up in time.
Source: http://news.naliyin.com/
