Skip links

PVC Pipes Extruder Safety Precautions

PVC pipe extruder machines can be used efficiently, maintained in good working conditions, and extended in service life by correct and reasonable use. In addition to installation, adjustment, test runs, operation, maintenance and repair, the PVC pipe extruder machine has similar characteristics to a general machine, especially in its drive motor and speed reducer.

While the screw extruder has a unique working system, it has some distinctive characteristics, so special care should be taken when using it. A brief description of the operation method, maintenance, and maintenance of the extruder is given in the operating instructions.

PVC Pipe Extruder Machine Operation

For operators to grasp the extrusion process conditions correctly, they need to be familiar with the extruder’s structural characteristics, especially the screw’s structural characteristics, the heating and cooling control instrument’s characteristics, the head and assembly conditions, etc.

For operators to grasp the extrusion process conditions correctly, they need to be familiar with the extruder’s structural characteristics, especially the screw’s structural characteristics, the heating and cooling control instrument’s characteristics, the head and assembly conditions, etc.

1. Preparation for Driving

  1. The raw materials for extrusion molding should meet the required drying requirements. If necessary, further drying is required, should sieve to remove agglomerates and mechanical impurities.
  2. A further drying procedure may be required if necessary, such as ensuring that the electrical system is standard, the heating system is working correctly, the temperature control is working correctly, and a variety of instruments are working properly; low-speed test of the auxiliary machine empty car Operate and observe whether the equipment is operating normally; start the vacuum pump of the sizing table and observe if it usually works. Lubricate the lubricated parts of the equipment with oil.
    Remove any faults as soon as possible.
  3. The machine head must be installed in the following order according to the variety and size of the product. Select the specifications of the machine head according to the variety and size of the product.
    • Installation of the machine head on the extruder should be done as a whole.
    • In preparation for assembling the machine head, wipe off any grease applied during storage, check the cavity for bruises, scratches, and rust spots, polish the cavity if necessary, and then apply silicone oil to the runner.
    • The plates of the machine head should be assembled in order, high-temperature grease should be applied to the bolt threads, and then the bolts and flanges should be tightened.
    • To prevent overflow, place the perforated plate between the flanges of the machine head.
    • It is important to adjust the horizontal position of the die before tightening the bolts on the connecting flange between the extruder and the die head. The square die head can be adjusted horizontally, while the round die head should be based on the bottom surface of the finalized model. The mould’s bottom surface is leveled.
    • The connecting flange bolts must be tightened, as well as the machine head fastening bolts. Finally, the heating ring and thermocouple must be installed close to the outer surface of the machine head.
    • Check if the main engine centerline is aligned with the positioning sleeve, then tighten the bolts. Connect the sizing sleeve’s water pipes and vacuum tubes.
    • Open the water inlet at the bottom of the hopper and the gearbox while turning on the heating power supply to evenly heat the machine head and cylinder. valve of the exhaust vacuum pump. During heating, each section’s temperature is first adjusted to 140°C, then kept at 140°C for 30-40 minutes after reaching 140°C. After that, the temperature is raised to that of average production. If your machine reaches the temperature required for regular production, please let it rest for about 10 minutes to stabilize each part before starting production. Heat preservation times vary depending on the extruder used and the raw material used. Temperatures should be kept consistent inside and outside the machine for some time in order to prevent the meter from showing the correct temperature while the actual temperature is lower. When the material is inserted into the extruder at this time, the actual temperature is too low, and the melt viscosity is too high. Overloads the machine’s axial force and damages it.
    • In the hopper, feed the raw materials for driving.

2. Drive

  1. Whenever the temperature is constant, you can drive the extruder. To eliminate the difference in thermal expansion between the bolts and the head, tighten the extruder’s head and flange bolts again before driving. A machine head’s bolts should be tightened diagonally. The flange nuts must be tightened consistently. Otherwise, the material will leak.
  2. If driving, select the “Ready to Start” button, connect the “Start” button, and slowly adjust the screw speed knob. The screw speed begins slowly, then gradually speeds up while adding a small amount of material. When feeding, pay attention to how the host ammeter and various indicator heads change. The screw torque must not torque meter). Before the plastic profile is extruded, no one can stand directly in front of the die to prevent injury accidents caused by bolts breaking or due to damp and foaming raw materials. After the plastic is extruded from the die of the machine head, the extrudate needs to be slowly cooled and led to the traction device and the shaping die, and these devices are activated. Then according to the indicated value of the control instrument and the requirements for extruded products. Adjust each part accordingly to make the entire extrusion operation reach a normal state. And add enough material as needed. The twin-screw extruder uses a metering feeder to feed evenly and at a constant rate.
  3. When the die is evenly discharged, and the plastic is suitable, it can pull into the shaping sleeve. Judgment of the degree of plasticization requires experience. Generally, it can judge according to the appearance of the extruded material. That is, the surface is glossy, free of impurities, no foaming, burnt material, and discoloration, and the extruded material is squeezed by hand to a certain extent and does not appear. Burrs and cracks have a certain degree of elasticity, which means that the material is plasticized well. If the plasticization lacks, the screw speed, barrel, and head temperature can adjust appropriately until the requirements are met.
  4. During the production process of the PVC pipe extruder machine, check whether the various process parameters are expected according to the process requirements and fill in the process record sheet. According to the quality inspection standards, check the quality of the profile products and take timely solutions when problems are found.

2. Parking

  1. Turn off the barrel and head of the PVC pipe extruder machine, and stop heating when the screw is exposed.
  2. Stop the screw and auxiliary machines as well as the power supply to the extruder and auxiliary machines.
  3. Disassemble the machine head by opening the connecting flange. Clean the perforated plate and various parts of the machine head. To prevent damage to the inner surface of the machine head during cleaning, the residual material in the machine head should be cleaned with steel laws and steel sheets. Then the plastic adhering to the machine head should be removed with sandpaper, polished, and coated with engine oil or silicone oil.
  4. The screw and barrel must be cleaned. Restart the main engine after removing the head, add parking material (or crushed material), and clean the screw and barrel. To reduce wear, the screw should be running at a low speed (about sr/min) at this time. After the stopped material has been crushed into powder and completely extruded, compressed air can be used to repeatedly blow out the remaining pellets and powder from the feeding and exhaust ports until there is no residual material in the barrel, at which point the screw speed can be reduced to zero and the extrusion can be stopped. Turn off the main power supply and the cold water supply valve.
  5. The safety items that should be considered when extruding are electricity, heat, mechanical rotation, and loading and unloading of heavy parts. To ensure safe production, the extruder workshop must be equipped with lifting equipment for assembling and disassembling the head, screw, and other heavy parts.

The screw extrusion system is maintained in two ways: daily maintenance and regular maintenance.

  1. Daily maintenance is routine work that is completed during start-up and does not consume equipment operating hours. The primary goal is to clean the machine, lubricate the moving parts, tighten loose threaded parts, and check and adjust the motors, control instruments, various working parts, and pipelines on a regular basis.
  2. After the extruder has been continuously operated for 2500-5000h and the machine has been shut down, regular maintenance is usually performed. The machine must be disassembled in order to inspect, measure, and identify the wear of the main parts, replace parts that have reached the specified wear limit, and repair damaged parts.
  3. It is not allowed to run empty to avoid the screw and the machine from rolling.
  4. If abnormal noise occurs during the operation of the extruder, it should stop immediately for inspection or repair.
  5. To avoid damage to the screw and barrel, strictly prohibit metals or other debris from falling into the hopper. A magnetic absorption component or a magnetic frame can be installed at the material inlet of the barrel to prevent iron debris from falling into the barrel. The material must be pre-screened.
  6. Maintain a clean production environment and avoid mixing garbage and impurities into the material, which can block the filter plate, reducing output and quality and increasing machine head resistance.
  7. It is important to keep electricity, heat, mechanical rotation, and loading and unloading heavy parts in mind when extruding. Lifting equipment is required in the extruder workshop so that the head, screw, and other heavy parts can be assembled and disassembled safely.
  8. Regularly calibrate the temperature control instrument to check the correctness of its adjustment and the sensitivity of control.
  9. Reducer of general standard. Examine the wear and failure of gears and bearings in particular. The gearbox should be lubricated with the oil specified in the machine manual, and the oil should be added to the specified level. The lubrication will not reverse if the oil is too low, and the service life of the parts will be reduced; too much oil, high heat generation, high energy consumption, easy oil Deterioration also renders lubrication ineffective and damages the components. To ensure the amount of lubricating oil, the sealing gasket (ring) should replace the oil leakage part of the reduction box.

10.The inside of the cooling water pipe connected to the extruder is prone to scale formation, while the outside is prone to corrosion and rust. During maintenance, a thorough inspection should be performed. Excessive scale will clog the pipeline and prevent the cooling effect from working. Water leakage will occur if the rust is severe. As a result, descaling and anti-corrosion cooling measures must be implemented during maintenance.

11.It is critical to inspect the wear and contact of the brush on the DC motor that drives the screw. The insulation resistance value of the motor should also be measured on a regular basis to see if it is greater than the specified value. In addition, inspect the connecting wires and other parts for rust and take precautions.

12.Designate someone to be in charge of equipment maintenance and keep detailed records of all maintenance and repair situations in the factory equipment management file.