PVC pipe extrusion production operation rules
2022-08-01
1. Before starting the machine, the maintenance personnel conduct a comprehensive overhaul of the operating units and main components of the host.
1. Check the gear box of the main engine and whether the throttle of the reduction box is normal;
2. Check whether all parts of the main engine and electrical appliances work normally, and check whether the drainage is open and whether the compressed air pressure is normal;
3. Check whether the main body shield is clean;
4. Check whether the screw cooling oil circuit is smooth;
5. Check the sensitivity of all operating switches and whether the governor is zero, and whether the emergency stop is in place;
6. The mold worker is responsible for replacing the mold, and carefully inspecting the heating ring of the die head to confirm that it is normal before delivering it to the operator for use.
2. Install the production die head, the setting sleeve and the sealing pads at both ends of the cooling box as required, and adjust the height of the bracket in the water tank and the height of the setting sleeve to be basically the same.
3. After the operator confirms that the host is normal, start the machine according to the following steps.
1. Turn on the main power switch, open the screw oil pump of the extruder and the water supply valve. Make sure that the mold is suitable, the nozzle is smooth without clogging, the height of the supporting roller is suitable, the vacuum glue can block the vacuum, the pressure of the tractor is moderate, the cutting machine clamps the block, the knife feed is suitable, and the flaring machine is normal.
2. Turn on the heating power switch of the extruder, set the temperature of the heating section and the temperature of the screw to be 70 °C, and the other sections to be 130 °C (Note: the small mold is heated for 1 hour, and the large mold is heated for 1.5 hours)
3. When the temperature of each section reaches the above set value, the temperature of each heating section will reach 150 °C, and the bolts should be tightened again for the newly replaced mold.
4. When each heating section reaches 150°C, set each temperature to 5-10°C lower than the data required for production, and the temperature of each section cannot be lower than 150°C. (Note heating for 0.5 hours)
5. Start the twin-screw, and slowly and evenly start to clean the machine material. The screw speed should not exceed 30% of the load at 0-5r/min, and the temperature of the oil pump should be set to 90℃.
6. According to the temperature display data and according to the humidity to determine the material arrival position and gradually increase the speed. While increasing the rotation speed, observe the change of the current of the host machine. If the current is stable, continue feeding. If the current continues to rise, slow down the feeding, and wait for the current to stabilize before feeding.
7. Determine the cleanliness of the barrel and die head by the inner and outer surfaces of the cleaning material. When the cleaning material is cleaned and the temperature has reached the production value, stop adding the cleaning material, open the feeding system, and adjust the feeding speed by controlling the torque at about 40% (40% of the normal production current value).
8. Until the material flows out of the die head, adjust the screw until the thickness is uniform. (Note: The material coming out of the die should be pulled off immediately, not too long or piled up in a ball)
9. When the extruded material is difficult to pull apart by hand, prepare for traction, start the vacuum pump of the extruder, and adjust it to the normal value.
10. When the material enters the vacuum setting cylinder, start the water pump immediately, and adjust the traction speed to reach the normal state.
11. When the whole line of the pipe has passed through the vacuum water tank and is on the tractor, turn on the water spray volume, turn on the vacuum pump of the vacuum setting box, and adjust the vacuum value to about 0.4par.
12. When the round tube passes through the cutting machine, the cutting machine can be turned on to the automatic state.
13. Measure the tube production and wall thickness, observe the quality of the inner and outer surfaces of the tube, and adjust the corresponding parameters. When the qualified products are produced to the tractor, put the printer and start printing.
Five, emergency stop steps
1. When it is found that the water is cut off and erected, the parking steps should be taken to deal with it.
2. Power failure (more than 20 minutes) - when a power failure is found, the power supply should be cut off immediately, the material of the die head should be cut off, the mold removal process should be carried out according to the mold disassembly and assembly steps, and the valve should be closed. When a short-term power failure is found, follow the normal power-on steps.
6. Operation points
1. The operator should be familiar with the emergency stop button and the work flow of this position, and can deal with it in the event of an emergency.
2. Manually add the machine material every time the machine is turned on, and after the cover is closed, observe whether the extruder exhaust port has material adhered to it.
3. The distance between the sizing sleeve and the die should not be too close (125px~250px).
4. When starting up normally, pay attention to the extruder load (current), and the load data cannot rise too fast, and the twin-screw speed and manual feeding speed should be slowly increased.
5. When stopping normally, it should be noted that the load of the extruder cannot exceed the normal value.
6. There should be no water droplets on the upper surface of the pipe between the cooling vacuum and the tractor, and it should be clean and free of water.
7. The nozzle of the inkjet printer should be removed every time the material is cut off, and the length of the pipe should be measured with a steel tape measure.
8. Fill in the "Extrusion Process Parameter Record" according to the process control index of this post.
7. Patrol inspection
Feeding system - extruder - sizing box - printer - tractor - cutting machine - flaring machine
1. The inspection time should be every 15 minutes/time, weigh the product once every hour and fill in the "Product Weighing Record Form".
2. Inspection content
1) Whether there is material in the barrel of the feeding machine, and whether the feeding machine is working normally.
2) Check whether the oil level of the extruder gearbox, the feeding gearbox and the screw is normal, whether the cooling water of the gearbox and the water source of the vacuum pump are circulating, and clean the filter screen at the water inlet in time.
3) Check whether the main engine temperature is abnormal, the main engine speed and current, the feeding speed and current, and whether the melting pressure and melting temperature are normal.
4) Check whether the vacuum of the main engine is normal, generally between 0.04-0.06MPa.
5) Check the barrel and mold heating line for damage, and observe whether the discharge of the die is smooth.
6) Check whether the vacuum of the sizing box is normal. It is generally between 0.02-0.04 below 200, and between 0.04-0.06MPa above 200. Check whether the water level of the sizing box is normal and whether the pressure of the water gauge is normal. Water strainer.
7) Check whether the inkjet printer is working normally, whether the font size of the inkjet code is appropriate, whether the handwriting is missing, and whether the ink and solvent are missing.
8) Check whether the oil level of the tractor motor reduction box is normal, whether the pressure is normal, whether the jaws tighten the pipe normally, and whether there is any deformation offset.
9) Check whether the cutting machine has an alarm, whether the hydraulic oil is lacking, and clean the sawdust once every hour, check whether the cutting saw belt is loose, whether the feed and retract screws are loose, and clean the sawdust in the motor junction box.
10) Measure the wall thickness, outer diameter and length of the pipe, and make a record. If it is found that the wall is biased, the thickness is not allowed, and the length and outer diameter are not allowed to report and modify it in time.
11) Check whether the surface of the pipe is smooth and whether there are dents and cracks, and report and deal with it in time.
12) Observe whether the hydraulic oil, water and electricity of the flaring machine are normal. Pay attention to whether the feeding, heating, bracket translation, forward and backward pulling, and forward and backward of the flaring die are working properly.
13) Check whether each photoelectric switch is in the normal working position and working state.
14) Check whether the flaring of the pipe after flaring is good and whether there is any offset.
15) The pipes are put into storage to reduce scratches and falls. Each post should be dedicated to each inspection department, find faults in time, deal with them when they have the ability to deal with them, and report to the monitor when they are not sure, and must not deal with them without permission. If there is a fault in each post for a long time to find or report, the individual will be warned after discovery, and the individual will be held accountable for downtime or equipment damage.
Eight, safety precautions
1. When equipment failure affects safe production, the operation must be stopped immediately. If the equipment failure is not eliminated, it cannot be restarted.
2. The operator must wear protective equipment, and the hair should not be over the shoulder to ensure the safety of personal and equipment.
3. The equipment protection device cannot be dismantled at will or left unused.
4. The operator cannot stand beside the die or extruder to heat or bake other items.
5. When the operator installs the mold, the body cannot face the discharge port of the extruder.
6. When cleaning the printer, the spray liquid cannot be sprayed at people.
7. Strictly control various process indicators to ensure the smooth progress of safe production.