What are the Plastic Tube Manufacturing Process?

Plastic tube manufacturing process mainly includes core steps such as raw material preparation, mixing, extrusion molding, cooling and shaping, traction cutting, quality inspection, and packaging. Some processes may also involve secondary processing or special treatments. The following is a detailed introduction:

1. Raw Material Preparation

Main Raw Material: Select a suitable resin according to the pipe type. For example, PVC resin commonly used is SG-5, which looks like white flour with a particle size of approximately 0.2mm.

Additives: These include stabilizers, lubricants, plasticizers, fillers, and processing modifiers. These additives improve the processing performance, mechanical properties, and weather resistance of the pipe.

2. Mixing and Stirring

Add the main raw material and additives to a high-speed mixer according to the formula ratio. The material is heated to the set process temperature through self-friction between the material and the machine. Then, the material is cooled to 40-50℃ by a cold mixer before being added to the extruder hopper.

3. Extrusion Molding

Extruder Selection: Select a single-screw extruder or a twin-screw extruder according to the pipe specifications and production requirements. Twin-screw extruders have better plasticizing effects and shearing capabilities, making them suitable for direct extrusion of powdered raw materials. Extrusion Process: The screw rotates under the drive of the transmission system, pushing the plastic into the barrel for heating and plasticization. An extrusion die is installed at the front end of the extruder; the plastic forms a preform of the desired shape as it passes through the die.

Temperature Control: Strict temperature control is required at each stage of the extrusion process to ensure the plastic is fully plasticized and does not decompose. For example, in PVC pipe extrusion, the feeding section temperature is typically 100-140℃, the plasticizing section 150-170℃, the homogenizing section 160-180℃, and the forming die 170-190℃.

4. Cooling and Shaping

Vacuum Shaping: The extruded preform enters a vacuum shaping chamber. A vacuum system forces the preform to adhere tightly to the inner wall of the sizing sleeve, while cooling water is sprayed to rapidly cool and shape the preform.

Cooling Methods: In addition to vacuum shaping, immersion in a cooling water tank can be used for further cooling to ensure dimensional stability of the pipe.

6. Quality Inspection and Packaging

Quality Inspection: The cut pipes are inspected for appearance, dimensions, mechanical properties, and chemical properties to ensure product quality meets standards and customer requirements.

Packaging and Warehousing: The inspected and qualified pipes are packaged, and the product name, specifications, quantity, and manufacturer information are clearly marked on the packaging before storage.

7. Special Processes and Secondary Processing

Secondary Curing Process: To address the poor low-temperature toughness of PPR pipes, a secondary curing process can be used. This process is carried out at 105℃ for 4 hours, which stretches and re-crystallizes the molecular chains inside the pipe, thereby reducing its low-temperature brittleness.

Socket and spigot processing: For some pipes, the socket and spigot ends are processed at the manufacturer using a thermal expansion method on an flaring machine; others are processed manually. Socket and spigot processing is a crucial step in pipe connection, requiring a tight, leak-proof connection.

Double-wall corrugated pipe forming: For special pipes such as double-wall corrugated pipes, a special mold with an inner and outer layer flow separation structure is used to simultaneously extrude two layers of molten polyvinyl chloride. Precise control of compressed air pressure and cooling water temperature ensures complete outer corrugation and tight fusion of the inner and outer walls.

Qingdao Xueyu Molding Products Co., Ltd. is mainly engaged in the design and manufacturing of injection molds, injection molding and secondary processing (spraying, pad printing, ultrasonic welding, stamping), etc. For more information about plastic tube manufacturing process, please contact us.

Website: www.xyzmould.com

Address: No.18 Henan Head Road, Henan Head Community, Jihongtan Street, Qingdao Industrial Park, Shandong Province, China

Email: wangmiaotian8@163.com