Plastic Sheet Extruder Machine is a device that processes plastic raw materials into continuous plastic sheets. Its working principle is mainly to enter the barrel of the extruder through the hopper. There is a heating device outside the barrel to heat and gradually melt the raw materials. There is a screw in the barrel, and the screw rotates under the drive of the motor. The rotation of the screw pushes the molten plastic material forward, which is similar to the working method of a screw conveyor. During the movement, the material is further plasticized and mixed evenly. Finally, the molten plastic is extruded through the die at the front end of the barrel to form a continuous plastic sheet. The shape and size of the die determine the shape and thickness of the extruded sheet. For example, to extrude a thin sheet, the die outlet is a narrow slit shape.

Ⅰ. Main components

1. Extrusion part

Screw and barrel: The screw is the key component of the extruder, and it has different functional sections. It is generally divided into a feeding section, a compression section, and a metering section. The feeding section is mainly used to allow the raw materials to enter the screw smoothly, and its screw groove is usually deep; the compression section is used to compact and plasticize the raw materials, and the screw groove gradually becomes shallower to compress the material; the metering section accurately controls the flow and pressure of the material to ensure that the thickness of the extruded sheet is uniform. The barrel provides support for the screw, and its heating system can make the plastic raw materials reach the appropriate processing temperature.

Heating and cooling system: The heating system is usually an electric heating ring surrounding the barrel, which is used to heat the plastic raw materials to a molten state. Different plastic raw materials have different processing temperature ranges, and the heating system needs to accurately control the temperature. The cooling system is mainly used to cool the screw and barrel to prevent the plastic from overheating and degradation. For example, when the temperature of the screw is too high for a long time, the cooling system will cool it down by air cooling or water cooling.

Transmission system: mainly includes motors and reducers. The motor provides power for the screw, and its power is selected according to the production capacity of the extruder and the characteristics of the plastic raw materials. The reducer is used to adjust the speed of the screw. The control of the speed is crucial to the extrusion speed and quality of the sheet.

2. Mould part (die): The design of the die is determined according to the specific shape and size requirements of the plastic sheet to be produced. For flat sheets, the die is a flat slit shape, and the width and thickness of the slit can be adjusted as needed to accurately control the thickness of the sheet. For some special-purpose sheets, the die will be designed to be more complex, such as with an internal flow channel to make the plastic melt more evenly distributed during extrusion.

3. Traction part: The traction device is generally composed of one or more pairs of traction rollers. The surface of the traction roller has a certain degree of roughness, which is used to increase the friction between the plastic sheet and the plastic sheet, so as to stably pull the extruded sheet out of the die. The speed of the traction roller can be adjusted to ensure the uniform thickness of the sheet by matching the extrusion speed. For example, if the traction speed is too fast, the sheet will become thinner; otherwise, it will become thicker.

4. Cutting part (optional): After the plastic sheet of a specific length is produced, it needs to be cut. The cutting device can be a simple manual tool, or an automatic circular saw or hot cutter, etc. The automatic cutting device can cut according to the set length or time interval, and the cutting accuracy is high, which is suitable for large-scale production.

Ⅱ. Application field

Packaging industry: used to produce various plastic sheets for packaging, such as food packaging, pharmaceutical packaging, daily necessities packaging, etc. For example, polyvinyl chloride (PVC) sheets can be used to make transparent cosmetic packaging. It has good transparency and barrier properties, which can effectively protect the product and show the product appearance.

Construction industry: In the construction field, plastic sheets for heat insulation, waterproofing and other purposes can be produced. For example, polystyrene (PS) foam sheets can be used for building insulation. It has good heat insulation performance and can reduce the energy consumption of buildings.

Automobile industry: used for automobile interior and parts manufacturing. For example, polypropylene (PP) sheets produced by extruders can be used to make fabrics for car seats. This sheet can be customized according to the design requirements of the car, such as adding flame retardant, antibacterial and other functions.

Electronic industry: used to make housings, packaging and insulation materials for electronic equipment. For example, polyethylene terephthalate (PET) sheets have good electrical insulation and mechanical properties and can be used to make circuit board insulation layers and display screen protective films for electronic devices.