1.Purpose

The machine set includes the JT-50 high-efficiency, energy-saving extruder, capable of continuously extruding pipes of PE, ABS, PC, etc., of corresponding diameters, widely used in construction, agriculture, chemical, and other industries.

2.Structural Overview

The machine set consists of the JT-50 extruder paired with dies of corresponding diameters, through cooling calibration, traction, length-fixed tracking cutting, and discharging for inspection of finished products.

JT-50 Extruder Mainframe: Comprises a variable frequency AC motor, gear transmission, automatic feeding machine, extrusion system, heating and cooling systems, and electrical controls. The variable frequency AC motor transfers power through a V-belt to the gearbox, enabling the screw to achieve speeds of 3-60 r/min to accommodate various plastic extrusion needs.
Blow Molding Die Head: The die head primarily consists of a core, mold sleeve, splitter, pressure cover, screws, die head body, heating ring, and mold support. Surfaces in contact with plastic are hardened and polished to ensure fluidity of the plastic and uniform wall thickness, adjustable via four bolts.

Vacuum Calibration and Cooling Section: This part mainly consists of a calibration sleeve, support frame, calibration tank, vacuum system, and cooling system. The calibration sleeve is used to size the outer diameter of the pipe as it exits the die head. The entire tank is vacuumed (vacuum level -0.2 to -0.8 MPa) to ensure the outer diameter tightly fits the inner wall of the calibration sleeve. Simultaneously, the calibration tank cools the pipe with water. The cooling system includes a centrifugal pump, distributor, spray pipes, and nozzles. During operation, the nozzles spray cooling water on the pipe from various directions, with the water entering the tank from the nozzles equaling the amount leaking from the drain.
Traction Device: The traction device mainly includes a transmission system, traction chain belt, clamping mechanism, adjustment system, side plates, and base. The motor uses a variable frequency drive to adapt to different extrusion speeds of pipes.
Cutting Device: Mainly consists of a frame, saw base, saw blade, clamping part, and pneumatic part. The clamping and cutting parts can move along the guide rail on the frame in the direction of the extruded plastic pipe. During cutting, the saw base relies on the motor to drive the saw blade for rotational cutting, while the saw base returns to its original position via a pneumatic cylinder.

The movement speed of each cylinder is controlled by adjusting the air pressure (2.5-3 Kg/cm^2) with an air pressure valve. When the control button is set to manual, the operator can perform the aforementioned cutting actions by pressing the corresponding buttons individually.

3.Main Technical Parameters:

JT-50 Single Screw Plastic Extruder:
- Motor Model: Y-7.5KW-6 frequency conversion
- Power: 7.5 KW
- Reducer Speed Ratio: 12.5:1
- Fan Model: DF-1, 85W
- Heating Power: 7.6 KW
- Dimensions: 2200 × 650 × 2100 mm
- Extrusion Rate: 35~50 Kg/h
- Weight: 800 Kg
Dies:
- Sizes: φ5, 9.6, 17, 26.7, 32 mm
- Calibration Sleeves: H68 brass
- Total: 5 sets
Vacuum Calibration Cooling Tank:
- Length: 5 m, 3 vacuum chambers
- Vacuum Pump Motor Power: 4 KW
- Cooling Water Pump Power: 1.1 KW (2 units), 0.75 KW (1 unit)
- Vacuum Generator: One set
- Maximum Calibration Pipe Diameter: φ32 mm
- Dimensions: 5000 × 800 × 1700 mm
- Weight: 1000 Kg
Traction Device:
- Pipe Diameter Range: φ5-50 mm
- Traction Line Speed: 0-5 m/min
- Track Type: Caterpillar, effective length 1.5 meters
- Drive Motor: 4 KW variable frequency speed control
Cutting Machine:
- Motor: 0.75 KW
- Encoder length memory, high-precision linear bearing slider.
- Control: PLC module, display screen.

4. Installation

4.1 The machine should be installed on a solid ground. The foundation must be a concrete structure with a buoyancy greater than 80mm. After placing the machine according to the installation holes, grout the bolts and wait for proper curing before final tightening.

4.2 During the tightening of the machine, use a level to ensure it is flat, with a horizontal error less than 0.05%. The center height of the main and auxiliary machines should be consistent.

4.3 The inlet and outlet water pipes of the calibration device should be connected with hoses to facilitate the movement of the cooling trough.

4.4 The laying of electrical wires on the traction and cutting devices should account for their potential movement, and all electrical control devices should be located at the control station in front of the vacuum tank.

4.5 Alongside the installation of the machine set, the power supply, air supply (compressed air not less than 6 Kg/cm²), and cooling water systems must also be installed.

5. Trial Operation

5.1 Manually move all parts of the transmission system to check for flexibility and reliability. Fill the gearbox with clean lubricating oil and then install the safety cover.

5.2 Power up and operate all parts to check for flexible and reliable movement.

5.3 Supply air to check if all pneumatic parts are coordinated and well-sealed.

5.4 Conduct a water trial to check for any leaks in the piping.

5.5 Detailed records should be kept during the trial run.

6. Maintenance and Care

6.1 It is strictly forbidden to mix impurities such as sand and hard objects into the materials.

6.2 For the initial 60 hours of operation, run the main motor at no more than 70% load, ensuring the current does not exceed 12A.

6.3 Avoid collisions and stretching of the cooling and vacuum pipelines.

6.4 Before each shutdown, close the hopper’s outlet, extrude the remaining material in the barrel, and then turn off the machine.

6.5 Immediately after stopping, dismantle and clean the die head and the cooling calibration sleeve using soft metal tools (such as copper rods and blocks) to avoid damaging their working surfaces. Remove the heating ring from the die head before dismantling. Handle all parts gently during assembly and disassembly. Apply rust-preventive oil on the surface of the cooling sleeve if the machine is to be left idle for an extended period.

6.6 Other items should be operated according to the individual machine’s instruction manual.

7. Appendix:

This section contains the electrical schematic diagrams necessary for troubleshooting and maintenance.

8. Specific Operational Examples:

Step 1: Before powering on and connecting water and air supplies, check that all connections are correct and meet safety standards.

Step 2: Ensure the gearbox is filled with sufficient lubricating oil.

Step 3: Turn on the drying hopper’s heating and drying system, set the temperature to 80-100°C, and dry for more than 2 hours.

Step 4: Start the main engine’s heating system. First, turn on the mold temperature control switch, then sequentially activate the temperature controls for each section, setting a reasonable extrusion temperature (which is not the melting point of the plastic).

Step 5: Once the plastic in the drying hopper has dried and the temperatures of the main engine sections have reached the set values, wait about 10 minutes before opening the feed gate. Simultaneously, turn on the main engine’s frequency conversion start switch and slowly adjust the speed knob.

Step 6: As the plastic melt exits the die, attach a prepared small plastic tube to the extrudate and stretch it. Based on the extrusion rate of the main engine, start and adjust the speed of the traction machine to synchronize with the main engine.

Step 7: Immediately start the vacuum box’s spray cooling system, then activate the vacuum system.

Step 8: Adjust the vacuum pressure based on the size requirements of the pipe (typically 0.02 to 0.08 MPa) and adjust the main engine’s extrusion rate according to the wall thickness requirements of the pipe.

Step 9: During the trial run, check the uniformity of the pipe’s wall thickness. If uneven, adjust the four adjustment screws on the side. Here’s how: First, mark near the die on the plastic pipe with a marker; loosen the screw at the thick wall, tighten the opposite screw slightly, and check the wall thickness. Repeat until the wall thickness is uniform.

Step 10: Once the wall thickness is evenly adjusted, check if the overall dimensions of the pipe wall are too thick or too thin. If too thick, speed up the traction machine or slow down the extruder to thin the pipe wall slightly. Reverse if necessary.

Step 11: Check whether the rubber blocks on the traction machine are too tight or too loose, and adjust accordingly.

Step 12: Check the accuracy of the automatic cutting machine’s size and make necessary adjustments. Set an appropriate number of points to achieve the correct size. For example: Initially set to 1000 points, measure the actual size of the tube after automatic cutting, then divide the actual millimeter measurement by 1000 points to determine the actual size per point.

Step 13: Shutting down the machine is particularly important in the operation. Specifics: First, close the feed gate and shut down the drying system; once the plastic is completely extruded (judged by no material exiting the die), adjust the main engine and traction machine frequency knobs to zero, then press the stop button. Subsequently, turn off the vacuum, water pumps, traction, temperature control, and finally cut the main power.