How to properly use Extruders

Source:GEMWELL Updated:2015-08-28 Views: 1636Courses
  Correct and reasonable use of extrusion machine, the machine can be fully effective, to maintain a good working condition, extend the life of the machine.
  A screw extruder, including machine installation, adjustment, commissioning, operation, maintenance and repair of a series of links, it has a general machine in common use, mainly in the drive motor and reduction gear installations. But screw extruder system of work that is extrusion system, but unique characteristics, particular attention is characterized in a screw extruder should be.
  Machine installation, adjustment, test machines generally used in extrusion machine instructions are clearly defined, this method of operation of the extruder summarized as follows:
  The operator must be familiar with the operation of the structural characteristics of their own extruder, in particular, to correctly grasp the structural characteristics of the screw, heating and control instrumentation characteristics, the nose assembly of the cooling properties and the like, in order to properly grasp the extrusion process conditions, the right to operate the machine.
  Different plastics extrusion operation method is not the same, but also has its similarities. Introduced a variety of products at the same extrusion procedure and issues should pay attention to the following operations.
1, the preparatory work before
  (1) for the extrusion of plastics. Raw materials shall meet the requirements needed for drying, if necessary, the need for further drying. And the material was sieved to remove lumps aggregates and mechanical impurities.
  (2) Check the equipment in the water, electricity, gas and each system is normal, ensure that the water, gas flow, does not leak, the electrical system is normal, the heating system, temperature control, various instruments are working and reliable; auxiliary air dryer low speed test operation, observe whether the device is working properly; start vacuum shaping table, whether to observe work; slippery parts in a variety of equipment lubrication. If found fault immediately removed.
  (3) installed head and calibrator. Depending on the product variety, size, head size selected. The following sequence will head installed.
  ① nose should fit together, the whole mounted on extruder.
  ② former head assembly shall wipe away grease when saving painted, carefully check whether the cavity surface bumps, scratches, rust, make the necessary polish and then coated with a layer of silicone oil flow path.
  ③ sequentially each head plates are assembled together, the threads of the bolt coated with high temperature grease, then tighten the bolts and flange.
  ④ porous plate is placed between the head flange to ensure that pressing the perforated plate without flash.Should be adjusted before
  ⑤ without tightening the coupling head and extruder die flange bolts fastening the horizontal position, adjust the level of available square head level meeting, round head shape model places soled surface as a reference by the head die the bottom surface leveling.
  ⑥ tight connection flange bolts, tighten the head fastening bolts, install heating coil and a thermocouple, pay attention to the heating coil to the outer surface in close contact with the head.
  ⑦ installation calibrator and adjust position, the centerline check the host, the calibrator is aligned with the tractor. After adjustment, tighten the fixing bolts. Connecting pipes and tubes of each calibrator.
  ⑧ turn the heating power of the nose, Jane uniform heating temperature. Open at the bottom of the hopper and the gearbox cooling water pump inlet and exhaust valves. When the temperature of each heating temperature adjusted to 140 ℃, when the heat until the temperature rose to 140 ℃ 30-40min, and then the temperature is raised to a temperature of normal production. Until the temperature rose to normal production at the desired temperature, then hold for about 10min, so that each part of the machine temperature to stabilize before they can start production. Insulation length of time depending on the model Extruders and plastic raw materials varieties vary. Incubation period of time to make a consistent temperature inside and outside the machine, so the meter indicates the temperature has reached the required temperature, while the actual temperature was low, at this time if the material is put in extrusion machines, because the actual temperature is too low, the material melt viscosity is too large, it will cause axial force overload and damage the machine.
  ⑨ will boot into the hopper of the raw materials used to prepare for use.
2, boot
  (1) can be turned on after the thermostat, before turning and extrusion machines should head flange bolts tightened once again to eliminate the bolt head difference in thermal expansion, the order of the head of the bolt is tight angle tightening, forced to be uniform ʱ?? When tightening the head flange nuts, it requires around elastic consistent, otherwise expected to run.
  (2) Power, selected by "Prepare boot" button, followed by "on" button, then slowly rotate the screw speed adjustment knob screw speed slow start. Then gradually accelerate, while a small amount of feed. Pay close attention to changes in the host indicating ammeter and various indicator head case when feeding. Screw torque should not exceed the red mark (typically 65% ​​-75% torque table). Before being extruded plastic profile, no person shall stand in front of the die, in order to prevent the bolts pulled off or put wet bulb due to raw material and other reasons arising from injuries. Plastic extrusion die from the head, it will take the extrudate slowly cooled and lead the traction device and stereotypes die, and start these devices. Then according to the indicated value control instruments and extruded products requirements. Each section be adjusted accordingly, so that the entire extrusion operation to normal status. And, if necessary add a little material, the use of a twin-screw extruder feed dosing uniformly constant velocity.
  (3) When the discharge die uniform and plastic excellent traction can be good people calibrator. Plasticized empirically determine the extent required, in accordance with the general appearance of extrusion material can be judged that the shiny surface, no impurities, no foam, coke material and color, hand out material squeezed down to a certain extent does not appear burrs, nicks, there is a certain flexibility, this time a good description of plastics materials. If the plasticizing screw speed adjustment may be appropriate to bad, barrel and head temperature until it reaches the requirements.
  (4) In the extrusion process, the process should require periodic inspection of various process parameters are normal, and fill process sheets. Quality inspection by the quality inspection standard product profiles, identify problems and timely corrective action taken.
3. Stop
  (1) Stop feeding, inside the plastic extrusion machines burnishing, when exposed screw, turn off the power cylinder and head, stop heating.
  (2) Close Extruder and auxiliary power supply, the screw and auxiliary equipment stops.
  (3) Heading coupling flanges, disassembly handpiece. Clean up various parts of the perforated plate and the nose. To prevent damage to the inner surface of the nose, the nose of the residual material within the law applied steel, steel proceeds to clear up, and then use sandpaper to adhere to the plastic in the nose in addition to grinding and polishing, coated with oil or silicone anti- rust.
  (4) removal of the screw, barrel, after removing the head, restart the host, plus stop material (or broken material), washing screw, barrel, then screw the choice of low-speed (sr / min or so) to reduce wear. Expected to be shut down completely crushed into powder extrusion, the available compressed air from the feed inlet and exhaust ports repeatedly blown residual pellets and powder until the barrel is really no residual material after the screw speed down to zero, stop Extruders , turn off the main power supply and the cold water of the total valve.
  (5) should pay attention to safety out of the project are: electricity, heat, handling and other rotating machinery and heavy components. It must be equipped with lifting equipment, assembly and disassembly nose, and other heavy components between the screw extruder machine, in order to ensure safety in production.
6, extrusion machine Maintenance
  Screw extrusion system uses routine maintenance and regular maintenance are two ways for maintenance.
  (1) Routine maintenance is a regular routine, it does not account for work equipment operation, usually done during the boot. Focus on clean machine, lubricate all moving parts, easy to loose screw fastening member, timely inspection, adjustment motors, control instruments, the working parts and lines.
  (2) regular maintenance is generally in continuous operation 2500-5000h extruder machine shut down for after the machine requires the disintegration of inspection, measurement, identification of the main components for wear, replace worn reached a predetermined limit of parts, repair damaged parts.
  (3) does not allow empty machine running, in order to avoid screw and Jane rolled hair.
  (4) extrusion machine during the operation if unusual noise occurs, immediately shut down for inspection or repair.
  (5) prevent metal or other debris falling into the hopper, to avoid damaging the screw and barrel. To prevent iron debris into the barrel, the barrel may be feeding material into the suction mouth mounted magnetic component or magnetic planes to prevent debris falling into the material must be screened in advance.
  (6) Note that the production of a clean environment, rendering garbage clogging the filter plate material contamination, affecting the product yield, quality and increasing resistance nose.
  (7) When Extruders take longer to stop using anti-rust should be coated with grease on the work surface screw, Jane, nose and so on. Small screw should be suspended in the air or placed in special wooden box, and pad level with wood, so as not to screw deformation or bumps.
  (8) Periodic calibration temperature control instrumentation, check its accuracy and sensitivity adjustment control.
  (9) extruder gearbox maintenance and the general standard reducer same. Mainly to check the gears, bearings and other wear and failure conditions. Manual gearbox should specify the use of the machine oil, according to the provisions of the oil level to join the oil, the oil is too low, lubrication is not reversed, reduce parts life; too much oil, heat a large, multi-energy, oil and easy metamorphism, also makes lubrication failure, the consequences of damage to the part. Gearbox oil spill sites should be replaced seal (ring) to ensure that the amount of lubricant.
  (10) the inner wall of the cooling water pipe subsidiary extruder easily furring external corrosive rust. Maintenance should be done carefully checked, scale can clog the pipeline too, reach the cooling effect, severe corrosion may leak, cleaning and corrosion must be taken care of cooling measures.
  (11) of the drive screw is rotated to focus on checking DC motor brush wear and exposure, if the insulation resistance value of the motor should be measured regularly at a predetermined value or more. In addition to check the cable and other components are rusty, and the use of protective measures.
  (12) designate a person responsible for equipment maintenance. And detailed records included in the file management of plant equipment maintenance and repair for each case.

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