The high-speed bubble film machine is widely used in the packaging industry to produce bubble films, which play an important role in protecting and cushioning various products. Understanding its working process is essential for ensuring efficient and high-quality production. This article will detail the working process of the high-speed bubble film machine in a clear and organized manner, covering each stage from raw material preparation to the final product collection.
I. Raw Material Preparation Stage
Raw Material Procurement and Inspection
Firstly, appropriate polyethylene (PE) resin pellets, the main raw material for bubble film production, are purchased according to production requirements. When the raw materials enter the factory, strict quality inspections are carried out to check key indicators such as the uniformity, purity, and melt index of the pellets to ensure they meet production requirements. For example, if the melt index is too high, the bubble film may be too soft and difficult to form during production; if it is too low, the processing difficulty will increase, affecting production efficiency. By conducting inspections, the stability of the raw material quality is ensured, providing a reliable foundation for subsequent production.
Raw Material Drying Treatment
If the raw material contains excessive moisture, defects such as bubbles and holes will occur during the processing, affecting the quality and performance of the bubble film. Therefore, the purchased PE resin pellets are usually placed in a drying device for drying treatment to reduce the moisture content to a certain standard. The drying temperature and time need to be precisely controlled according to the characteristics of the raw material. Generally, the drying temperature is between 60°C and 80°C, and the drying time is 2 to 4 hours to ensure that the raw material is fully dried without thermal degradation.
II. Extrusion Molding Stage
Extruder Preheating and Start-up
The dried raw material is added to the hopper of the high-speed bubble film machine's extruder. Before starting the extruder, the barrel, screw, die head, and other related parts of the extruder need to be preheated. The preheating temperature usually increases gradually from the hopper end to the die head end, generally set between 150°C and 220°C, and is adjusted according to the raw material formula and product specifications. The purpose of preheating is to enable the raw material to melt quickly and form a uniform melt after entering the screw, facilitating subsequent extrusion molding operations. When the temperature of each part reaches the set value and stabilizes, the extruder motor is started, and the screw begins to rotate at a low speed, gradually pushing the raw material forward.
Screw Extrusion and Plasticization
As the screw rotates, the raw material is subjected to intense shearing, extrusion, and friction within the barrel, gradually melting and plasticizing. The screw structure design is crucial for the plasticization effect of the raw material. A gradually changing screw is usually adopted, with the screw groove depth gradually becoming shallower from the feeding section to the metering section, which can effectively compress, mix, and plasticize the raw material, making the temperature, pressure, and viscosity of the melt more uniform. During the extrusion process, close attention should be paid to the changes in parameters such as the pressure, temperature, and current of the extruder to ensure the stability of the extrusion process. If the pressure is too high, it may indicate that the die head or filter is clogged, and the High-Speed Bubble Film machine needs to be stopped for cleaning in a timely manner; if the temperature is too high, the raw material may decompose, affecting product quality, and the screw speed or heating temperature needs to be appropriately reduced at this time.
Die Head Extrusion Molding
The plasticized melt is pushed by the screw to the die head. The die head is a key component for bubble film molding, and its internal structure design determines the shape and size of the bubble film. Inside the die head, the melt passes through specific flow channels and dies to form a film with a certain width and thickness. At the same time, the die head is equipped with a blowing device to inject air evenly into the film to form bubbles. The blowing pressure and flow rate need to be precisely controlled according to the requirements for the size and density of the bubbles. Generally, the blowing pressure is between 0.1 MPa and 0.3 MPa, and the flow rate is between 100 L/min and 300 L/min. By adjusting the temperature, pressure, and blowing parameters of the die head, bubble film products with different specifications and performances can be produced.
III. Cooling and Shaping Stage
Cooling Method Selection
The bubble film extruded from the die head has a relatively high temperature and needs to be cooled and shaped to stabilize its shape and performance. There are two common cooling methods: air cooling and water cooling. Air cooling uses the cold air generated by a blower to cool the bubble film. This method is simple to operate and has a low cost, but the cooling speed is relatively slow and is suitable for producing thinner bubble film products. Water cooling directly cools the bubble film with circulating water, which has a fast cooling speed and can effectively improve production efficiency. However, a corresponding water circulation system and drying device need to be equipped to prevent residual water on the bubble film surface from affecting product quality. In actual production, an appropriate cooling method can be selected according to factors such as the thickness, production speed, and equipment conditions of the product.
Cooling Process Control
Regardless of the cooling method used, the cooling process needs to be precisely controlled to ensure that the bubble film cools down uniformly during the cooling process, avoiding problems such as film surface shrinkage, deformation, or stress concentration caused by uneven cooling. For air cooling, the wind speed and direction of the blower should be reasonably adjusted to ensure that the cold air evenly covers the bubble film surface; for water cooling, the temperature, flow rate, and pressure of the circulating water should be controlled to ensure the stability of the cooling effect. At the same time, attention should be paid to the traction tension of the bubble film during the cooling process to avoid film rupture due to excessive tension or film slack due to insufficient tension. Generally, the traction tension is controlled between 5N and 15N and is appropriately adjusted according to the thickness and width of the bubble film.
IV. Traction and Winding Stage
Function of the Traction Device
The bubble film after cooling and shaping needs to be transported forward by the traction device. The role of the traction device is not only to provide a certain traction force to enable the continuous and stable production of the bubble film but also to stretch the bubble film to adjust its longitudinal orientation and physical properties. The speed of the traction directly affects the thickness and draw ratio of the bubble film. Generally, the traction speed is slightly faster than the extrusion speed to ensure that the bubble film is in a moderately stretched state. For example, when the traction speed is increased by 10% to 20%, the thickness of the bubble film will correspondingly become thinner, and the tensile strength will increase, but the toughness may slightly decrease. Therefore, during the production process, the proportional relationship between the traction speed and the extrusion speed needs to be reasonably adjusted according to the performance requirements of the product.
Key Points of the Winding Operation
The drawn bubble film is finally wound and packaged. The quality of the winding directly affects the appearance and usability of the product. During the winding process, it is necessary to ensure that the bubble film is neatly and tightly wound on the core, avoiding problems such as loose winding, off-center winding, or wrinkling. For this reason, the winding device is usually equipped with a tension control system and a deviation correction device. The tension control system can automatically adjust the winding tension according to parameters such as the thickness, width, and winding diameter of the bubble film to ensure the stability of the tension during the winding process; the deviation correction device can detect the edge position of the bubble film in real-time and adjust the position of the winding roller to keep the bubble film centered during winding. At the same time, the winding speed should also match the traction speed to avoid excessive stretching or compression of the bubble film during the winding process.
The above is the complete working process of the high-speed bubble film machine. Each stage is closely connected, and any problem in one stage may affect the quality and production efficiency of the final product. Therefore, during the actual production process, operators need to strictly follow the operating procedures, pay close attention to the operating status of the equipment and the changes in process parameters, detect and solve problems in a timely manner to ensure that the high-speed bubble film machine can produce high-quality bubble film products efficiently and stably.
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