How to cut the film with a slitting machine

The slitting film of the slitting machine is to release the large film material through the unwinding mechanism, pull and pass through a set of pre-positioned blades, so as to cut into the material that meets the width of the customer's requirements, and then wind the finished film roll through the winding mechanism. The specifications of the finished film coil of good quality are accurate, and the length and width are strictly guaranteed within a small error range. The paper core of the roll film should be flat and parallelistic, and the width should not be less than the slitting width. The end face of the film coil after slitting is straight, and there are no wrinkles or defects.

We believes that if we want the slitting machine to cut the film, we need to do the following aspects.

Choose the right film slitting machine blades

The choice of blade of the slitter plays a crucial role in cutting the film. Generally speaking, you can refer to the thickness of the film, the film below 20um is selected 0.2mm square blade, the film from 20 to 34um is selected with a thickness of 0.4mm square blade, and the film thickness is more than 35U is recommended to use a round blade. In addition to thickness, the choice of inserts should also take into account the properties and materials of the film, and constantly try in practice to obtain the best slitting results. The blade structure of the film slitting machine is described in detail in the article "Introduction and Selection of the Cutting Knife Form of the Slitting Machine", and will not be repeated here.

The blade should be kept sharp during daily use, as material is wasted if the blade is blunted or damaged. According to the actual wear and tear of the blade, set a certain film slitting length and replace it in advance. After confirming that all four corners of the square blade have been worn out, they can be scrapped directly. If the round blade is found to have a notch or burr, stop using it, and remove the blade and sharpen it before continuing to use it.

Choose the right slitting process according to the type of film

The slitting machine produced by Delish Machinery adopts the appropriate slitting process for each film performance and specification, and quantifies the parameters of the slitting machine such as tension, speed and other indicators. The speed of the slitting machine is too slow will affect the production efficiency, too fast will affect the quality of slitting, the film is easy to occur in the process of high-speed operation, such as stripes, deviation or staggering, etc., and controlling the appropriate slitting speed is an important means to improve the yield rate of the film. In addition, the mutual tension between unwinding, traction, slitting and winding should be controlled, so that the film substrate is always in a stable tension state, and deformation and displacement can be avoided in the process of increasing or decreasing speed.

The main winding methods of the film are surface winding, center-winding and center-surface winding. The tension of the surface winding method comes from the unwinding tension, and the contact pressure depends on the weight of the coil and the air pressure of the winding shaft, which can wind larger diameter coils but is not suitable for easily stretched materials such as PE. The center winding provides tension on the reel by acting on the rewinding shaft, and the tension curve can be effectively controlled by changing the torque, and no contact pressure is generated. The tension of the center surface winding comes from the center of the reel and the surface roller force, and it is possible to slitting larger film rolls with a smaller reel arm and larger diameter, but it is not suitable for slitting harder materials such as PVC because the contact pressure is difficult to control precisely.

The solution to the problem of slitting film

During the operation of the slitting machine, as the film winding diameter increases, and the tension slowly becomes smaller, the attenuation rate should be reduced to maintain a constant tension. On the other hand, when the tension gradually increases as the winding diameter increases, the attenuation rate should be increased. When the diameter of the roll increases and the contact pressure begins to increase, the roller pressure should be reduced. The hardness of the film roll depends on the amount of air entering the film during winding, when the film roll is soft, the winding tension should be increased, and the winding tension should be reduced when it is hard. More common problems are detailed in the article "Quality Problems in Film Slitting" and will not be repeated here.

In addition, the operation of the slitter machine in a shutdown state, such as changing rollers, adjusting tools, changing film rolls, condensating films, etc., will also affect the quality of the film. Poor handling of each process may bring trouble and waste of materials to the next process. Therefore, how to cut the film well by the slitting machine is a comprehensive topic, and it is necessary to continuously summarize the experience in practice and give full play to the best state of the slitting equipment.