Preparatory steps before starting the sheet extrusion line
- Pre-dry the pellets of the extruded profile and further dry if necessary.
- Check whether the components, water, and air systems are in a standard, safe and reliable state. The parts that need lubrication should have sufficient lubricating oil. The running part should regularly fille with lubricating oil. The entire extrusion and shaping system should initially align. Lock the position after the extruded product is normal.
- Preheat the head, body, and screw to the temperature required by the process. Simultaneously, open the cooling jacket at the bottom of the hopper and pass in cold water. After the extruder head reaches a specific temperature, heat the body.
- The machine needs to be kept at a constant temperature for some time before starting up because the temperature indicated by the temperature control instrument of the sheet extruder is ahead of the actual temperature. Suppose the temperature is not kept for a sufficient time. In that case, the material will not be preheated enough. The material flow’s viscosity will be too high, and the Axial screw overload can damage equipment and even personal safety.
- When each component reaches the specified temperature, the machine head part’s connecting bolts should tighten. Simultaneously, it is hot, and the connection status should check to ensure that no material leakage occurs during operation.
- Check the feeding hopper and the remaining material. There must be no foreign matter, especially metal and other hard debris, to not damage the extrusion screw or hopper.
- Before starting the machine, replace it with a clean filter, check whether the machine head meets the product variety and size requirements and whether the parts of the machine head are clean.
- Clean the operation site, keep the main engine and auxiliary equipment and the operation table clean, and place the raw materials, products, and tools in an orderly manner.
- After each part of the whole machine reaches the predetermined temperature and is consistent with the thermometer test, it will be stable for 0.5-1h, and then start the trial run.
- Start each operating equipment and check whether it is operating normally.
Note: Once the heating temperature reaches the required temperature, all couplings must tighten again to achieve the required coupling strength.
Start-up steps of sheet extrusion line
- Turn on the main motor.
- Adjust the screw speed to 15-20 rpm, observe the plasticization of the material and the discharge of each part of the die, and adjust each part’s temperature according to the extrusion situation until average production.
- When the extrusion is standard, start the vacuum system of the extrusion exhaust section.
- Introduce the extruded material into the shaping die, water tank, and traction device, adjust the shaping die to be concentric and concentric with the machine head, adjust the center height of the traction block, and press the profile with appropriate pressure, adjust the traction speed to make the product wall thickness consistent Claim.
- Turn on the cold water, then turn on the vacuum pump, lock the setting box, make the product stick to the setting sleeve, observe whether the wall thickness and size of the profile are qualified, whether the product is bent or warped, and analyze the cause of the abnormal situation according to the actual situation, Make corresponding adjustments, and mark the products after average production to distinguish test-machine products and finished products.
The shutdown steps of the sheet extrusion line
- Open the vacuum control valve.
- Turn off the vacuum pump and remove the vacuum setting table.
- Set all temperature controls to 120°C.
- Close the hopper plug.
- Let the host run idling.
- Turn off all temperature controls.
- Turn off the main switch.
Die replacement steps
- The temperature sensor and pressure sensor on the Panasonic die head and adapter (the temperature of the die head must be the operating temperature).
- Unplug the heating ring plug on the die and adapter.
- Remove and clean the die and adapter.
- Turn on the main motor.
- Set the screw speed to 20-25rpm so that the residual material is extruded from the barrel.
- Turn off the main motor.
- Install the adapter and die head.
- Plugin the temperature sensor and pressure sensor, as well as the heating coil plug.
- Set to the temperature required for production and start to preheat the die.
Precautions for sheet extrusion line
- It is not allowed to run idle for a long time after starting up, not to scratch the screw or barrel.
- Ensure that the raw materials are clean and strictly prevent metal debris or other complex parts such as screws from falling into the feeding port and damaging the screw and barrel.
- When feeding, it is necessary to ensure continuous feeding. For this reason, there must be sufficient materials in the feeding hopper. If continuous feeding cannot ensure, the machine must shut down immediately. It is strictly forbidden to run empty without materials.
- After the new extruder starts to run for several hours, it should re-grow into the V-belt to avoid slipping.
- During continuous long-term operation of the machine, check the lubrication and temperature rise of each part on time, pay attention to the equipment’s operation at all times, and stop and check immediately if there is any abnormality.
- If the production power is interrupted, the main drive and heating will stop. When the power supply is restored, each section of the barrel must be heated to the set temperature for some time before starting.
- When it is difficult to eject the screw after processing, a screw-type screw separator can be used instead of hammering to avoid damage to the screw.
- After the extruder is used for 500 hours, there will be iron filings or other impurities in the gearbox’s oil. Clean the gears and replace the lubricating oil in the gearbox. In the future, the lubricating oil must replace according to the specified time in the manual. In general, check the wear of gears, bearings, and seals of the reduction gearbox once a year, and replace severely worn parts in time.