Flexibility and modularity of diaphragm manufacturing equipment

In recent years, the development of the field of barrier films has changed greatly. In order to meet the requirements of fast delivery, film manufacturers must shorten the production cycle as much as possible; on the other hand, individual companies must even produce hundreds of different film products within one year because the types of films that users need are increasing. Thin film equipment suppliers are trying to face challenges with film manufacturers from two aspects of increasing the flexibility and modularity of the production line.

One of the challenges posed by the constant changes in the film market is that after the film manufacturers purchase the equipment, it is difficult to predict what will eventually be produced. Faced with this problem, some leading equipment manufacturers put forward their solutions: modular design of the production line, while improving the function of the relevant automatic control system, so that the device has a high degree of flexibility and optimize the combination of capabilities, so that in the need The equipment can be upgraded and remodeled easily and economically.

Extruder: From raw material to melt

In the film production line, the main task of the extruder is to process various raw material particles into a uniform melt. Of course, it must also ensure that raw materials can be changed without any problems, and that there is no need to replace the screw or a long cleaning time when the raw material is switched.

There are at least two extruders to choose from, one is a grooved feed extruder and the other is a smooth feed extruder. Smooth extruders are more suitable for barrier film production. The smooth feeding section can process all kinds of key raw materials needed to produce the barrier film very gently and evenly, such as EVOH, PA6, PET or COC and so on. To ensure perfect melt quality, Kiefel's extruders also use a specially designed mixing section with minimal shear forces. The mixing section can guarantee the controllability of the melt temperature and the stability of the bubble. In addition, in order to save space and reduce maintenance costs, this extruder uses a gearbox direct drive technology that does not require a drive belt, and is stable and quiet during operation.

Film blowing machine die: from multi-channel to ring die

The pre-distributor evenly distributes the melt stream exiting each extruder to a multi-layer annular flow path. The binary stack pre-distributor guarantees a lower pressure drop, good self-cleaning ability, a small temperature difference between the various parts of the melt and a time difference in the residence time of the melt in the flow channel.

The stacked pre-distributor also guarantees a lower, more convenient die height. The accuracy of the thickness and distribution of the individual layers of the multilayer co-extruded barrier film is determined by the design of the pre-distributor, the spiral core, and its processing accuracy, and the precision of the internal clearance of the die at the junction of each layer plays an important role. Because the mold opening force is very low, the coaxial distribution of the spiral core can accurately guarantee the structure and thickness distribution of each layer; the optimized design can also guarantee a short multi-layer melt confluence path, which can significantly reduce the temperature of nylon ( PA) layer adverse effects on other temperature-sensitive material layers.

Wind Ring: From Melt to Bubble

The air ring plays a decisive role in many aspects such as the quality of the film and the economics of the overall production process, because it affects not only the optical properties of the film, but also the stability of the bubble and the total yield. The double-lip air ring meets these requirements: the air blown from the gap below avoids contact between the film and the first lip while ensuring the stability of the bubble; the air blown from the upper gap is used to cool the bubble and ensure the bubble Stability, make sure it is not in contact with the second cooling lip. This method avoids bubble movement, making subsequent processing easier, cooling more efficient, and yields higher.

Traction device: from bubble to double flat membrane

Since the barrier film is generally hard, when the film bubble is converted into a double-layer flat film through the quenching process, the requirements for the traction and quenching device are relatively high. The basic principle is: The longer the extinction frame, the less the wrinkles of the film. Temperature control also plays a pivotal role in it, and this depends to a large extent on the material of the quenching rack.

In the KIEFEL traction device, the primary nip roller and the new reversing roller are located on a rotating platform which is used to support the heaviest part of the traction device and ensures the stability of the traction device. The advantages of the new design are also reflected in the details. For example, it is now possible to achieve a minimum flattening angle of 6.5 degrees on the quenching rack with a longer extinction length, thereby significantly improving the flatness of the film. The linear servo motor is used to control the angle and position of the quench bubble rack. Its parameter settings can be saved in the KIRION-automatic control system. When the product is changed, it can be directly called to avoid time-consuming repetitive adjustments.

With increasing processing costs, rising raw material hardness, and increasingly stringent film quality requirements, the production of smooth, crease-free, scratch-free films poses challenges for equipment. KIEFEL has specially designed a brush roller with diagonal nylon bristles.

This brush roller design provides more advantages than traditional flattening devices. For example, the uniformity of the overall cooling of the film plays a crucial role for excellent film flatness. Aluminum roller or carbon fiber roller will accumulate heat during use and cause its own temperature to rise, which will have an adverse effect on the cooling and thickness of the film. Nylon roller can ensure the uniform cooling of the film during the entire production process, because the nylon brush The bristles are very fine, so the contact area with the film is also small, but the side area that can be used for heat dissipation is large.

Nylon brush roller also proved its value during the flattening of the film. In the case of using a normal device, the speed of the film at the same width during flattening is hardly exactly the same, often causing wrinkling or scratching. The soft bristles' movement can balance the relative speed and avoid the damage to the film quality. Since the contact area with the film is small, it is also possible to avoid the material sticking to the roller when the film is flattened. In many fields of application, this specially designed nylon brush roller guarantees perfect flattening of the high quality film and its optical properties.

These new features of the rotary traction system of KIEFEL have adopted a compact design, which ensures the stability of the system without increasing the space requirements. With the KIRION – automatic control system, it is also possible to set smaller rotation angles, reduce blistering, and have great benefits for products with high requirements for flatness. The zero position and rotation range of the rotating device can also be arbitrarily selected, and the parameters can be stored in the control system.

The biggest feature of the entire traction system is the zero-contact (ZEROTOUCH) air reversing roller system. Its patented shape and "hardslide" Teflon coating can eliminate scratches on the film surface. The patented air cushion protects the film from direct contact with the air reversing roll, ensuring excellent quality.

Winder: From flattening to perfect winding

A wrinkle-free, smooth, and precise-width film roll facilitates more efficient and economical processing. Therefore, in order to be able to optimize the winding of the film, KIEFEL and its subsidiary WINTECH divided the entire winding path into small independent sub-paths in KIRIONâ•“M. A thin film measuring and controlling system is equipped from the top of the secondary winder on the winder to ensure that the path of the film is "static" and eliminates irregular movements. The film tube can be cut easily and accurately.

The film that needs to be coiled enters each sub-path one after another. At each station, the film undergoes flattening, lubrication, and once again monitoring. It is particularly important to maintain stability without drift during the slitting of the film, otherwise it will cause unevenness of the film roll side or inconsistent width when slitting, thus affecting the overall product quality.

After slitting, the volumes will be flattened again thanks to the independent drive. The separately adjustable flattening roller does not cause tensile deformation of the film. The subtle speed difference guarantees the continuous flattening of the sub-coil. The subsequent winding station has a measurement and control system and must eliminate all external influences through it. For example, only when there is no deviation in the course of the film, it is allowed to leave the measurement and control system, is received by the carbon fiber roller, and is conveyed to the winding point through the integrated vacuum adsorption system, achieving perfect drift-free rolling. This is of particular importance for films with a shrinking function.

At the same winding point, the KIRION series winders offer a range of different winding methods:
· Surface rewind with constant contact pressure (CLP) function · Surface with or without constant contact pressure function and center rewind · Gap rewind · DCD (Dual Center Drive) center and clearance rewinding Pass these functions KIRION Series The winding machine is able to wind all the materials: The hardness of the film roll can be adjusted according to different material combinations.

Automation: Optimized monitoring

Automation systems are a necessary means for effective monitoring in complex production processes. A multi-language central control system including Chinese is installed on the entire production line of KIEFEL. The system exchanges data through a distortion-free bus system and is equipped with a touch screen with a traditional window interface. In addition to controlling all tasks, setting the thickness of the film is also extremely important for economic efficiency. Depending on the application, KIEFEL can provide the following different systems to suit different purposes:

·Die Thermal Control ·Wind Ring Thermal Control ·Air Ring Air Flow Control

About KIEFEL Extrusion GmbH

KIEFEL Extrusion GmbH specializes in the production of single or multi-layer co-extrusion blown film equipment using PE, PP, PA, EVOH, PET, PS and EVA as raw materials. It can provide blown film production lines with a screw diameter of 30 to 120 mm and a 9-layer technical film or barrier film. Currently, the company is using more than 3,600 blown film production lines worldwide. Major customers include: HPC (Sonoco), Formosa Plastics, RKW Tyco Group, and Barbier + Sopil.

The subsidiary WINTECH is located in Switzerland and its product applications include blown film, flat film, textiles, nonwovens, paper and laminates.