First, non-disassemble cleaning method

1. Resin cleaning method

Use a resin such as a polyester resin or an epoxy cleaner. Generally used in the cleaning or extruder of new equipment for a period of time, because some materials remain on the screw or the barrel is glued, the extrusion speed of the material becomes slower, and the color difference of the color change varieties is large, it can be used. This method.

Check whether the material on the machine is clean, clean the working table of the press, and set the required temperature of the washing screw. (Except for POM, PVC, TPE, TPU, the temperature must be higher than the screw production temperature of 30 °C). And the back pressure reaches the set value. The screw residue is shot out, and the cleaning material is added. The discharging is performed by the rapid---slow---fast---injection process. Pay attention to the color of the injected material. When the material is found to be discolored, manually press the screw to retreat. Empty injection; repeat the appeal process 3 times. The extruder is considered to be cleaned when the material is not produced in the original product or without the paste.

2, non-resin clearing method

Using a certain friction and easy to pulverize rice, corn, sawdust, toilet paper and other substances after the extruder is heated to the normal extrusion temperature, the friction generated between the screw and the barrel is used to remove the adhesion to the screw and Resin gel on the surface of the barrel. Experience has shown that the outer shell of rice has high hardness and high friction, and the effect of cleaning is better. After cleaning the machine in this way, it is necessary to open the screw barrel to check the condition of the cleaning machine. Under normal circumstances, it is necessary to re-clean the machine with the resin cleaning material before the official product can be produced.

The cleaning of the extruder without disassembling the machine has the advantage of reducing the time required to clean the machine; however, there is also a risk of incomplete cleaning.

Second, the dismantling method

1, the required tools

Some tools and cleaning materials to be used when disassembling the machine should include: goggles, heat-resistant gloves, copper scrapers, copper brushes, copper mesh, stearic acid, electric drills, barrels, cotton, etc. In addition to the above tools, you need to prepare:

4, 5 wooden sticks (diameter < screw diameter) × (length < injection stroke);

4, 5 wooden blocks (square, 100 mm × 100 mm × 300 mm); the removed screw should be placed on the wooden block to prevent damage to the screw.

a pair of pliers; waste cotton cloth;

a long stick or bamboo stick (diameter <screw diameter) × (length > length of the heating cylinder);

Non-flammable solvent such as trichloroethylene.

2, cleaning method

The first step in cleaning the extruder is to close the discharge port at the bottom of the hopper; depending on the extrusion process (the die may need to be removed to reduce the risk of excessive pressure at the front end of the extruder), it must be cleaned by a It is achieved by the operator: the operator observes the screw speed and torque from the control panel while observing the extrusion pressure to ensure that the system pressure is not too high. First, do not remove the die for cleaning. Immediately stop the mold and remove the die when the extrudate is completely converted from the processing resin to the cleaning resin, and then advance to allow the residual cleaning resin to flow out. The screw speed is then reduced to 15-25 r/min and this speed is continued until the melt flow at the front end of the die stops flowing.

2.1 Screw cleaning

Mechanical method:

The mechanical method is to heat the extruder to the working temperature, and manually or automatically push out the screw to push out the heat to remove the easily removed material.

Step 1: Disassemble the screw head, wipe the screw body with a waste cotton cloth to remove most of the resinous precipitate; remove the resin residue with a brass brush, or use a burner to heat the screw, then use waste cotton cloth or A brass brush removes deposits from it.

Step 2: Clean the screw head in the same way, stop the reverse ring, thrust ring and mixing ring, and brush with a brass brush.

Step 3: After the screw is cooled, wipe off all traces of the oil with a non-flammable solution.

Be careful not to scratch the surface of the part when cleaning. Before installing the screw head, apply a layer of molybdenum disulfide grease or silicone oil evenly on the thread to prevent the thread from seizing.

Fire roasting method:

The use of fire or fire to remove the plastic that is attached to the screw is the most effective and most effective way to see plastic processing units. (However, the acetylene flame should not be used to clean the screw. The temperature of the acetylene flame can reach 3000 °C. Cleaning with an acetylene flame will not only destroy the metal characteristics of the screw, but also significantly affect the mechanical tolerance of the screw.) After the screw is applied Use a blowtorch for cleaning immediately. Since the screw has heat during processing, the heat distribution of the screw is still uniform.

2.2 barrel cleaning

Step 1: First remove the nozzle head and the barrel head, and remove the residue adhering to the inner surface of the barrel with a brass brush.

Step 2: Wrap the end surface of the wooden rod or long bamboo with waste cotton cloth to clean the inner surface of the cylinder. During the cleaning process, the cleaned waste cotton cloth should be replaced several times.

Step 3: Clean the nozzle, especially the mating contact surface of the barrel and the nozzle. This process must be carried out with care to avoid resin leakage due to surface damage of the wipe.

Step 4: When the temperature of the barrel drops to 30 to 50 ° C, wet the waste cotton cloth with a solvent to clean the inner surface of the barrel again as described in the second step.

Step 5: Detect and ensure that the inner surface of the barrel is clean.

3, installation

After cleaning the screw and barrel, we need to reassemble the machine correctly.

3.1 Screw head installation

Step 1: Place the screw flat on two wooden blocks of equal height and operate the handle on the key groove.

Step 2: Evenly apply a layer of molybdenum disulfide grease or silicone oil to the thread of the screw head.

Step 3: Put the cleaned anti-reverse ring, thrust ring, mixing ring (some machines are not), and then insert the screw head in turn.

Step 4: Use the special wrench of the screw head to cover the screw head and screw it in the opposite direction to complete the assembly of the plasticized component.

3.2 Installation of the barrel head and nozzle

Step 1: Use a crane to lift the plasticized components and clean them carefully.

Step 2: Slowly push the plasticizing assembly into the barrel with the screw head facing outward.

Step 3: Align the light hole of the screw on the head of the barrel with the screw hole on the barrel, and align the mouth with a copper rod to make the matching plane close.

Step 4: Tighten the barrel head bolts and install the barrel head bolts.

Step 5: Evenly apply a layer of molybdenum disulfide grease or silicone oil to the nozzle threads.

Step 6: Screw the nozzle evenly into the screw hole of the barrel head to make the contact surface close.

Tighten the barrel head bolts to the appropriate torque value, waiting for the barrel, barrel head and its bolts to reach the same value for temperature compensation.