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Common problems and solutions in PE pipe extrusion process

Source:Suzhou Jplastic Me Precision Machinery Co., Ltd. Time:2019-07-16 Browse:629


During the production line of plastic pipes, due to the operator's lack of skill in the process and machine operation, plastic pipes often have rough outer surfaces, internal jitter rings, uneven wall thickness, and insufficient roundness. Therefore, the process must be adjusted in time to eliminate Failure of the plastic pipe production line can improve product quality.

1. Failure of plastic pipe production line: rough outer surface of plastic pipe

Adjust the process temperature; lower the cooling water temperature. The cooling water temperature of PE pipe is 20 ~ 25 ℃. Check the water circuit for blockage or insufficient water pressure. Check the heating ring of the barrel and the machine head for damage. Flow rate; check the properties and batch number of the raw materials; check the core temperature of the mold, if it is higher than the die section temperature, lower the core temperature; clean up the aggregate of the mold;

2. Failure of plastic pipe production line: groove marks appear on the outer surface of plastic pipe

Adjust the outlet water pressure of the sizing sleeve to achieve a balanced water output; adjust the nozzle angle in the vacuum sizing box to make the pipe cool uniformly; check the mold, sizing sleeve, cutting machine and other hardware for debris and burrs;

3. Failure of plastic pipe production line: groove marks appear on the inner surface

Check the inner tube for water. If it enters water, pinch the tube embryo just out of the mold to close the cavity; reduce the internal temperature of the mold; clean and polish the mold;

4. Plastic pipe production line failure: a jitter ring appears inside the pipe

Adjust the outlet water of the sizing sleeve to make the water evenly; adjust the vacuum of the second chamber so that the vacuum of the rear chamber is slightly higher than the vacuum of the front chamber; check whether the vacuum seal is too tight; check whether the tractor has a chattering phenomenon; Whether the material is uniform;

5. Plastic pipe production line failure: no vacuum

Check whether the water inlet of the vacuum pump is blocked, if it is blocked, perform dredging; check whether the vacuum pump is working properly; check whether the vacuum pipe is leaking; check whether the small hole in the middle of the core mold compression screw is blocked;

6. Failure of the plastic pipe production line: the outer diameter of the pipe is too poor

Adjusting the degree of vacuum can change the size of the outer circle; adjusting the traction speed can change the size of the outer circle; correcting the size of the inner hole of the sizing sleeve;

7. Failure of plastic pipe production line: poor roundness of pipe

Adjust the angle of the nozzle in the vacuum setting machine and the spray box to make the pipe cool uniformly; check the water level in the vacuum setting machine and the spray box and the pressure of the water pressure gauge to make the spray volume large and powerful; check the vacuum setting machine and the spray box If the water temperature is higher than 35 ° C, a chilled water system or a spray cooling box should be configured; check the water channel and clean the filter; adjust the process; check and correct the inner circle of the sizing sleeve; adjust the pipe guide clamping device to correct Ovality of the pipe;

8. Failure of plastic pipe production line: uneven wall thickness of pipe

Adjust the wall thickness on the mold; adjust the angle of the nozzle in the vacuum setting machine and the spray box to make the pipe cool uniformly; adjust the outlet of the sizing sleeve to make the water uniform; remove the mold, check whether the screws inside the mold are loose, and tighten again;

9. Plastic pipe production line failure: plasticizing temperature is too high

Adjust the process; adjust the heating temperature of the mold core, and ventilate and cool the mold; the shear heat of the screw is too high, replace the screw;

10. Plastic pipe production line failure: Inaccurate cutting length

Check whether the counting wheel is tight; check whether the counting wheel is swinging and tighten the fixing bolt of the counting wheel frame; check whether the cutting switch of the cutting machine is damaged; check whether the rotary encoder is damaged; whether the rotary encoder wiring is de-soldered (aircraft Whether the contact of the plug seat is good); each stand-alone shell (PE terminal) should lead the ground wire to a general ground point for reliable grounding, and the ground point should have a grounding post that meets the requirements of electrical grounding. No stand-alone shell (PE terminal) is allowed. Ground after series connection, otherwise interference pulses will be introduced, causing inaccurate cutting length;

11. Plastic pipe production line failure: co-extrusion identification strip problem

Co-extruded identification strip diffusion: Generally caused by improper selection of co-extruded materials used by users, special materials such as PE should be used, and the temperature of the extrusion section can be reduced if necessary;

The co-extrusion identification bar cannot be squeezed: stop the main extruder, start the co-extrusion machine first, turn on the co-extrusion machine for about 10 minutes, and then turn on the main machine;

Coextrusion labeling strip is too thin or too wide: It is generally caused by the mismatch between the coextrusion machine's extrusion volume and the pipe's traction speed, which should be adjusted

Co-extruder inverter frequency or change traction speed so that the two speeds can match;

The second reason is that the cooling water jacket of the co-extrusion machine does not pass cooling water;

In the actual production process of the pipe production line, there will be other abnormal situations, which should be handled according to the actual situation.