How To Solve The Problem Of Film Wrinkling During Die-cutting And Slitting?

The types of wrinkles include wrinkles, longitudinal wrinkles, transverse wrinkles, and linear wrinkles.

When the film is wrinkled, it means that the flatness of the film has been damaged to a certain extent. This is not allowed for any purpose of the film. It will not only affect the appearance of deep-processed products, but also cause quality defects in use, such as lack of coating, print etc.

Wrinkle: Also known as bottom wrinkle, initial wrinkle, etc., it is a wrinkle that occurs in a section of the paper core that is initially wrapped around the film. Because the wrinkle is mostly irregular dead wrinkle, the user generally discards the film when it is used to the wrinkling position.

The degree of wrinkling is an important indicator reflecting the cutting technology level of a film company. For films produced by different companies, the wrinkling length varies from several meters, tens of meters to hundreds of meters. The bigger the losses, the more research every film company is working on to improve slitting and wrinkling.

There are several ways to solve the bottom wrinkle

The wrinkles near the paper core cannot be stretched, which is largely related to the contact roller pressure of the slitting machine. Practice has proved that when the contact roller pressure is increased, the wrinkles increase, and when the pressure is reduced, the wrinkles decrease, and the air volume in the film roll increase, so that the gap between the films increases to reduce friction, which is beneficial to reduce wrinkling;

When improving the wrinkling, the control of the winding tension must be considered. If only the winding pressure is considered, the set value of the initial pressure should be very small. In special cases, the deceleration in the middle will cause defects such as deviation due to small pressure. , so the tension curve setting is also very important, and the winding pressure and tension must be properly matched;

The pressure on the paper core cannot be reduced indefinitely. If it is too small, the inner winding of the film roll will be too loose and the end face will appear star-shaped, which will cause the film to produce transverse wrinkles. Therefore, when setting the pressure curve, it should be adjusted to the end face of the film roll. There is no star and wrinkle can be minimized;

Under the same parameter conditions, the long specification is more likely to wrinkle than the short specification film roll, which means that the longer the specification, the worse the exhaust effect, and because the middle strength of the long specification paper tube is relatively poor, the paper tube in the slitting process. Slight bending can easily make the film in the middle of the film roll wrinkle for a long time, and when the paper core is long, under the high-speed rotation of the slitting, as the axis of the film winding, its straightness, concentricity, strength, surface Indicators such as smoothness are the most important. Generally speaking, the longer the paper core, the harder it is to ensure straightness and concentricity.

Therefore, the quality of the paper core is very important, and the inspection of the paper core must be improved. If the quality of the paper tube is found to be abnormal during the slitting process, it must be replaced in time. In addition, under the same parameter conditions, short-gauge film rolls are more likely to deviate than long-gauge film rolls, requiring greater winding pressure. Therefore, in the adjustment of wrinkling, the pressure setting can be appropriately reduced for long specifications to reduce wrinkles, while for short specifications, the pressure should be increased to prevent deviation.

The products that are cut inside and outside the slitting machine are wrinkled horizontally due to the different angles (wrapping angles) entering the rewinding pressure roller. Generally, it is caused by reducing the pressure during the slitting process to reduce wrinkling and should be effectively adjusted for different types of products. Slitting and pressure can effectively eliminate the generation of transverse wrinkles.

The degree of wrinkling inside and outside the slitting machine may also be different. Pay attention to comparing the wrinkling difference between the inside and outside of each slitting machine. If the difference is obvious, the specifications that are prone to wrinkling should be placed in the slitting process. The wrinkled side is cut.