Single Layer Film Blower: Analysis On The Forming Principle And Production Process Of Plastic Film

In the plastic packaging, grocery and manufacturing industries, single-layer film blowers are the basic core equipment of film production. They are widely used in the production of polyethylene protective film, bag film, agricultural film and ordinary packaging films. Compared with multilayer co extrusion blown film equipment, single layer membrane blower has simple structure, stable production and convenient debugging. Many workers operate equipment every day, but are not familiar with the molding principles and standard production process, which may lead to mismatch of equipment parameters, mismatch of process and frequent defects of finished products. This paper comprehensively analyzes the forming principle and complete production process of single-layer film blower to help practitioners understand the core logic of equipment, achieve stable mass production and accurate product control.
The core molding principle of a single-layer film blower is to use the thermoplastic properties of plastic and the blowing and pulling process to achieve thin film forming. Using common plastic particles such as PE and polypropylene as raw materials, the device converts solid plastic particles into uniformly flowing melt by heating and melting. It is then extruded into a tubular thin film rough through a die ring and combined with compressed air for internal expansion and external cooling molding. Finally, it is stretched, stretched and flattened to form a uniform thickness and transparent texture of plastic film. The whole process is a a continuous and integrated thermoplastic molding process, which does not require complex layered co extrusion structures. Single layer molding, simple process logic, high stability and controllable yield.
The material melting and extrusion of raw materials is the first core process in the production process, which directly determines the plasticization quality. Plastic particles enter the screw extruder through the hopper and continue to move forward as the screw rotates and squeezes. With the precise control of mechanical bulk partition temperature, plastic particles gradually melt, plasticize and homogenize. temperature control adjust the heating range according to the characteristics of the raw material to avoid excessive temperature that causes material to decompose and blister, or insufficient temperature that leads to incomplete plasticization and particle inclusion. At constant pressure, the The fully plasticized melt is pushed uniformly to the mold head position, which ensures uniform and stable discharge and lays the foundation for subsequent film formation.
Forming and blow molding are key steps in film forming. Homogenized melt is filtered and separated by precise die, then extrusion vertically from annular die to form tubular membrane tube with uniform thickness. At this point, the device through the built-in air pump to the constant compressed air into the tube, and the tube billet using air pressure to evenly inflate and stretch, forming a conforming film cylinder diameter. The inflation ratio of single-layer the single-layer blown film machine is controllable, and the air pressure and traction speed can be adjusted according to the width and thickness requirements of the product. Stable air pressure output can effectively prevent the dithering and uneven expansion of the membrane tube and prevent the thickness deviation and wrinkling of the membrane.
The cooling and molding processes directly affect the flatness and transparency of the films. The newly extruded high-temperature film cylinder a soft texture and is easy to deform. The single-layer blower adopts a an annular air ring cooling structure to cool the outer wall of the film cylinder in all directions by uniform cold air, so that the high-temperature melt solidifies quickly. The uniform air-cooling effect can lock the shape of the film quickly, eliminate defects such as bubble, ripple and deformation, and make the film surface smooth, transparent and uniformly thick. The speed and volume of cooling air can be adjusted according to the speed of production. In the process of high speed mass production, the air cooling intensity is increased to ensure that the molding speed is synchronized with the production rhythm, so as to achieve continuous and stable production.
Flattening and winding forming are the ultimate guarantee of finished product quality. After forming, the film cylinder is firmly clamped with a herringbone board to eliminate wrinkles and dislocations. Then the film thickness and tension are further adjusted by using traction roller to ensure smooth surface and uniform texture. The traction speed is closely connected with the extrusion and inflation processes, which forms a closed-loop cooperation and avoids film stretching deformation and thickness inhomogeneity caused by speed difference. Finally, after the guide roller correction, the whole machine rolled into a compact, regular film mother roll, completed the entire continuous production process. The equipment can adjust the winding tension according to the need, ensure the smooth end of the finished roll, uniform tension, easy to follow up cutting and bag processing.
In general, the production process of single-layer blower is logical, coherent and interlocking. From material melting, die extrusion, pressure inflation, ring cooling, to traction leveling, automatic winding, six processes are connected, precise coordination. According to the mature principle of thermoplastic blowing, the equipment can standardize, automate and continuously produce the film. Single layer film blower has the advantages of simple structure, convenient debugging, low failure rate and high cost efficiency. It is completely compatible with mass production of ordinary packaging films film and is the most popular and practical core molding equipment in the light industry.