During production, plastic pipes must be manufactured using equipment and processes tailored to their specific type. There are many varieties of plastic pipes, and the manufacturing techniques employed depend on the material’s properties and structural requirements. For example, single‑layer flexible plastic tubing is relatively simple to produce. When making such products, we first adjust the raw‑material formulation based on the desired performance characteristics; after blending in a kneader, the compound is fed into a pelletizing machine to produce pellets. The pellets used for flexible tubing differ from those for rigid pipe, so the formulation must be fine‑tuned to suit each application. Once the pellets are produced, the flexible tubing can be extruded directly on an extruder to achieve the required shape; after extrusion, water cooling is applied to complete the process. Rigid plastic pipes, in addition to extrusion, often require vacuum‑forming equipment to assist with shaping. As for composite plastic pipes, two or more extruders may be needed for co‑extrusion or in‑line extrusion, with the specific approach selected according to the product’s design and functional requirements.

1. Functions of PVC Pipe Production Line Equipment

Raw material blending: PVC stabilizers, plasticizers, antioxidants, and other additives are sequentially fed into a mixer in specified proportions and according to the process sequence. The friction between the materials and the mixing equipment raises their temperature to the set processing range, after which a cooling mixer reduces the temperature to 39–49°C. At this point, the blend can be transferred to the extruder hopper.

2. Extruder Section: This machine is equipped with a metering feed system that ensures the extrusion rate matches the feed rate, enabling stable production. The feeding section features a larger diameter, providing a greater heat-transfer surface area and higher shear rates, which facilitate material plasticization. In contrast, the metering section has a smaller screw diameter, reducing both the heat-transfer surface area and the shear rate on the melt, allowing extrusion at lower temperatures. As the screw rotates within the barrel, it plastifies the PVC compound and conveys it toward the die, achieving compaction, melting, and uniform mixing, while also facilitating venting and dehydration. The feed system and screw drive are both equipped with variable-frequency drives, enabling synchronized speed control.

3. Extrusion die section: The PVC, which has been compacted, melted, and homogenized through mixing, is conveyed by the screw to the die; the extrusion die is a critical component for pipe formation.

4. The vacuum shaping water tank is used for shaping and cooling tubular products. It is equipped with a vacuum system and a water circulation system for shaping and cooling, features a stainless steel tank body, and employs circulating water spray cooling. Additionally, the tank is fitted with a front-to-back traversing mechanism as well as manual adjustment devices for lateral and vertical positioning.

5. The haul-off unit is used to continuously and automatically draw the cooled, hardened pipe from the die head, with variable-frequency speed control.

6. Automatic Cutting Saw: After the stroke limit switch controls the cut to the required length, the saw performs automatic cutting and, following a delay, flips the pipe rack to enable continuous production. The cutting machine uses a fixed-length limit switch signal as its command to complete the entire cutting process, maintaining synchronization with the pipe‑conveying system throughout. The cutting operation is driven by both electric and pneumatic actuators. Additionally, the machine is equipped with a dust‑extraction system that promptly removes and recovers the cutting debris.

7. The material‑turning action of the material‑turning rack is controlled by a pneumatic cylinder via a pneumatic circuit. The rack is equipped with a limit switch: after the cutting saw has severed the pipe, the pipe continues to be conveyed; following a delay, the cylinder activates to perform the turning operation, thereby completing the unloading process. After unloading, the system automatically resets after a few seconds of delay, awaiting the next cycle.

Hebei Shuangda Rubber and Plastics Machinery Co., Ltd. is a modern enterprise integrating research and development, manufacturing, and sales of complete sets of extrusion equipment for rubber, silicone, and plastics. The company’s main products include rubber extruders, rubber hose extrusion lines, three‑layer composite sealing strip extrusion lines, silicone sealing strip production lines, plastic sealing strip production lines, plastic profile extrusion lines, plastic pipe extrusion lines, elastomer extruders, and other extrusion equipment, as well as production machinery for engineering seals, automotive seals, wire and cable applications, air‑conditioning hoses, braided hoses, automotive hoses, waterstop strips, and related products.