The best film quality cannot be separated from goo

2022-10-19
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Film quality cannot be separated from good coiling (Part 1)

after being extruded, the film is wound on the drum. In order to make the subsequent processing become no problem, the drum must meet different quality requirements. They must be unified into a barrel shape, and their edges should be neat without sharp edges. The surface shall not have any creases, pits or gas. The drum must have the same hardness over the entire distance to the core

film performance exerts an important influence on the reel quality, the failure maintenance of Jinan assaying impact tester and even the accessories required by the winder. For example, a film with a very flat surface requires more sophisticated coiling technology than HDPE film for T-shirt bags, which is relatively easy to wind. Moreover, the sensitive, gray and smooth surface or the post shrinkage of the film on the drum makes the winding more difficult. Similarly, whether the film has high elasticity or low elasticity, it will affect the quality of the drum

Figure 1 Schematic diagram of contact coiler with two coiling stations

basic principle of coiling

the contact roll and tower coiler used in film blowing and film extrusion represent two fundamentally different coiling concepts (Figure 1). The quality requirements for the final reel are undoubtedly the key to the selection of specific types of winders. However, practical considerations such as available space, operator experience, and investment costs also play a role. The selection of the winder requires an accurate understanding of how each component operates, as well as the winding and replacement process of the drum

there are two main steps in barrel winding. In the actual winding process, the film is rolled under a certain contact force. The system must be adjusted according to the increasing diameter of the drum, and the film roll must be transferred accordingly

the second step is to replace the reel when the reel is running. The reel is cut along its width and wound with a new core

Application and adjustment of contact force

the simplest way to drive the film roll is to press it on a motor-driven contact roll. The colloidal contact roll is usually staggered with grooves, so that the gas between the contact roll and the drum will not make the drum deviate. Moreover, pressing the contact roll against the film roll can prevent the last film roll from being blocked by gas between the film layers

in the simplest case, the actual contact between the contact roll and the reel (1) turn off the oil pump, and the electromechanical pressure can be generated by the fixed load of the reel. However, this contact force is neither constant nor adjustable. Today this winder can only be used in the simplest films. The higher quality coiler uses a pneumatic or hydraulic cylinder block, or a stepping motor system to press the film in a controlled manner throughout the diameter of the reel. This is particularly important for films that shrink on the roll

in most coilers, the necessary contact force is applied by pressing the moving installed reel against a fixed contact shaft. When the diameter of the drum increases, the film roll moves away from the fixed roll. The disadvantage is that the increasing weight will change the moment of inertia and the friction conditions of the movable installation reel. Therefore, it is very difficult to accurately control the contact force between the reel and the contact roller. For high requirements, the contact roller is movable and installed. Such a contact roller can be installed on a rod or suspended in the air in order to make up for the fixed load. In addition, the roll can also be moved horizontally from the film roll on a movable bracket. The contact force that this system can apply is very small, less than 50N. However, because all parts around the contact roller, such as the slitting system, also need to be removable when the roller needs to be replaced, the machine cost of such a small contact force is still very high

it will ensure that the raw material supply of Thornton new energy cathode material business is adjusted according to the roll diameter

the diameter of the film roll will increase during coiling. This increase in diameter must be balanced and stabilized by moving the reel or contact roll

where the reel moves, the contact roller is permanently installed in the frame. When the reel operates with the entry of the film roll, it will move away from the contact roll. The advantages of this system lie in the simple structure of the contact roll installation and the simple connection of components on the contact roll. The disadvantage is that the increasing weight of the reel affects the coiling process, as in the case of contact force control

where the contact roller can move, the coiling shaft is permanently fixed during the coiling process. When the diameter of the coiling shaft increases, the contact shaft will move. This delicate system ensures extremely smooth coiling because the movable contact roller has a stable weight and the reel is fixed in place

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