The ideal large volume adhesive material to be cut should have neat edges, consistent internal tension, and good concentricity. However, in actual production, there are many factors that can cause various defects.
Adhesive materials belong to composite materials and are composed of base paper, surface material, and adhesive. If the tension on both sides of the base paper or surface material is inconsistent, or if the adhesive coating is uneven, the tension on both sides of the composite adhesive material will also be affected, resulting in varying degrees of looseness and flatness on both sides of the large volume adhesive material.
Before laminating, the tension of the surface material and the base paper is required to be basically the same. If the tension difference between the two is large, the adhesive material will continuously deform during printing, causing inaccurate registration in one direction. Adhesive materials with this defect are not suitable for printing and processing on high-speed machines. The greater the printing speed and tension, the greater the deformation of the adhesive material, and the greater the problem of registration. Such materials can be printed on low-speed printing machines.
If the coating equipment is not accurate and there are quality defects in the adhesive material, and the operator lacks experience in adjusting the equipment, the end face of the adhesive material will be uneven. This defect must be corrected before cutting such large volume adhesive materials.
If the packaging of the finished large volume adhesive material is unreasonable during long-distance transportation, the material will be deformed due to environmental temperature and humidity changes. In addition, if stored for a long time, the adhesive material will lose moisture and cause relaxation, which will also cause edge deformation, making the cutting process difficult.
Due to the deformation of the iron core tube or paper core tube, there will be radial jumps (sometimes only one end jumps) in the large volume adhesive material on the feeding axis of the slitter rewinder machine. This radial jump will cause periodic changes in the tension of the adhesive material, affecting the tension stability of the adhesive material when it is cut into small rolls.
If conditions permit, the above defects can be improved by re-rolling or by re-rolling and placing them for a period of time to achieve physical equilibrium and stability.
The quality defects of large volume adhesive materials have a great impact on the quality of finished small rolls of adhesive materials. In this case, small rolls of adhesive materials have three impacts on registration during printing.
Material deviation
Due to inconsistent tension on both ends of the adhesive material, it will move to one side during printing. If this phenomenon is not serious, it can be solved or improved with the alignment device on the equipment. However, if the situation is severe, the material needs to be replaced.
Changes in the tension of the adhesive material
Changes in the tension of the adhesive material will cause inaccurate registration in the feeding direction during printing. The improvement method is to use a label printing machine with low feeding tension (such as equipment with reciprocating feeding). This is because the higher the tension of the slitter rewinder machine equipment, the greater the deformation of the adhesive material.
"S-shaped" adhesive material
The "S-shaped" swing of the adhesive material during printing causes inaccurate registration, which is the most common problem in adhesive label printing. This "S-shaped" phenomenon is irregular and difficult for operators to adjust. The uneven edges of the large volume adhesive material are one of the reasons for the "S-shaped" phenomenon in the small rolls of adhesive material after cutting.
