Extruder is very common in the plastics industry machinery, keep the extruder in the best working condition, can maintain product stability and improve production efficiency in the course of daily use, inevitably decline in production efficiency, this time we Need to clean and maintain the extruder.Next Xiaobian take you to understand some of the common cleaning methods of the extruder.
First, non-disassemble cleaning method
1, resin cleaning method
The method is to use resin, such as polyester resin or epoxy resin cleaning machine.Usually used in the new equipment or extruder after a period of time, due to the part of the material remaining in the screw or screw cylinder above the plastic material extrusion Slower, and the color of the color variety of color larger, you can use this method.
Check the machine material on the cylinder is put clean, clean plastic machine table, set the required screw washing temperature (except POM, PVC, TPE, TPU outside temperature must be higher than the screw production temperature 30 ℃), until the temperature And the back pressure reaches the set value. The screw residue shot into the air, adding cleaning materials, the material by the rapid --- slow --- rapid ---- injection process, pay attention to observe the color of the injection material, when found Material discoloration manually by screw back and then empty injection; repeat the appeal of the operation of the process 3. When the injection material does not produce the original color of the product or paste can be considered when the extruder has been cleaned.
2, non resin clearance method
The method uses a certain friction, but also easily crushed rice, corn, sawdust, toilet paper and other substances in the extruder heated to normal extrusion temperature, the use of these substances in the screw and the friction between the barrel to remove the adhesion In the screw rod and screw barrel surface of the resin.Experience has shown that the shell of the rice hardness, friction is very large, compared with the ideal result of cleaning machine.Use this method of cleaning machine, it is necessary to open the screw Check the clean-up situation, under normal circumstances also need to use resin-based cleaning material again after the clean-up, in order to carry out formal product production.
The cleaning of the extruder without dismantling the machine has the advantage of reducing the time it takes to clean the machine; however, there is also the risk of incomplete cleaning.
Second, disassemble cleaning method
1, the required tools
In the dismantling of the machine need to use some tools and cleaning materials should include: heat-resistant gloves, goggles, copper scraper, copper brush, copper mesh, stearic acid, electric drill, barrel ruler, cotton, etc. In addition to these tools Outside also need to prepare:
4, 5 sticks (diameter<螺杆直径)×(长度<注塑行程);
4, 5 pieces of wood (square, 100 mm × 100 mm × 300 mm); removed screw should be placed on the block to prevent damage to the screw.
A pair of pliers
Waste cotton
A long wooden stick or bamboo stick (diameter <螺杆直径)×(长度>Heating cylinder length);
Non-flammable solvents, such as trichlorethylene
2, cleaning methods
The first step in cleaning the extruder is to close the discharge opening at the bottom of the hopper. Depending on the extrusion process (the die may need to be removed to reduce the risk of overpressure on the front of the extruder), it must be cleaned by one People to achieve: the operator from the control panel to observe the screw speed and torque, while observing the extrusion pressure to ensure that the system pressure will not be too high.First do not remove the die for cleaning, in the extrusion resin completely converted from processing resin Immediately shut down and remove the die, and then in order to make the residual cleaning resin outflow Then reduce the screw speed to 15-25r / min, and this speed until the melt flow in the front of the die to stop so far.
2.1 screw cleaning
Mechanical Law:
Mechanical method is to heat the extruder to the operating temperature, the use of artificial or automatic introduction of the method, the screw out to remove hot materials while hot.
Step 1: Disassemble the screw head, scrape the screw body with a cotton cloth to remove most of the resinous precipitate, remove the resin residue with a brass brush, or heat the screw with a burner or the like, Brass brush to remove the sediment on it.
Step 2: Use the same method to clean the screw head, anti-thrust ring, thrust ring and mixing ring, brush brush with brass.
Step 3: After the screw is cooled, wipe off all traces of oil with a non-flammable solution.
Pay attention to cleaning, do not scratch the surface of the parts; Before installing the screw head, first evenly coated with a layer of molybdenum disulfide grease or silicone oil in the thread to prevent thread seizure.
Roasted fire method:
Use of fire or roasted to remove the plastic screwed on the screw, plastic processing unit is the most often seen is the most effective way (but can not use acetylene flame to clean the screw acetylene flame temperature up to 3000 ℃, with acetylene The flame cleaning of the cleaning screw will not only destroy the metal characteristics of the screw, but will also significantly affect the mechanical tolerance of the screw.) Immediately after the screw is used, the burner is cleaned with a torch. Heat distribution is still uniform.
2.2 barrel cleaning
Step 1: First remove the nozzle head, the cartridge head, with a brass brush to remove residues attached to the inner surface of the cylinder.
Step 2: Use waste cotton cloth wrapped in the end of the stick or long bamboo, cleaning the inner surface of the cylinder, the cleaning process, should be replaced by cleaning the waste cotton fabric several times.
Step 3: Clean the nozzle, especially the mating surface between the cartridge and the nozzle. Care must be taken to avoid scratches on the surface of the wipe resulting in resin leakage.
Step 4: When the temperature of the barrel drops to 30 to 50 ° C, moisten the waste cotton cloth with the solvent and wash the inner surface of the barrel again as described in the second step.
Step 5: Test and ensure that the inner surface of the cylinder is clean.
3, installation
After the screw and barrel cleaning is complete, we need to reassemble the machine correctly.
3.1 screw head installation
Step 1: The screw flat on the two pieces of the same height, in the keyway Department put the operating handle.
Step 2: Apply a layer of molybdenum disulfide grease or silicone oil to the threads of the screw head evenly.
Step 3: Wipe clean check ring, thrust ring, mixing ring (some machines do not), followed by sets into the screw head.
Step 4: Use a special screwdriver wrench, cover the screw head, tighten the opposite direction, to complete the plasticizing assembly.
3.2 cartridge head, nozzle installation
Step 1: Use a crane to level the plastified components and carefully wipe them clean.
Step 2: Slowly push the plasticizing unit into the barrel with the screw head facing outwards.
Step 3: Align the hole on the barrel head with the screw hole on the barrel, and align the hole with a copper rod so that the mating surface is tight.
Step 4: Tighten the cartridge head bolt and install the cartridge head bolt.
Step 5: Apply a layer of molybdenum disulfide grease or silicone oil to the nozzle threads evenly.
Step 6: Screw the nozzle evenly into the tapped hole of the barrel head, bringing the contact surface into close contact.
Tighten the barrel bolt to the appropriate torque value, waiting for the barrel, barrel head and bolt to reach the same temperature compensation value.