Debugging of extrusion die---
Operators must be familiar with the extruder they are operating, and must correctly grasp the characteristics of the screw, the control of heating and cooling, the characteristics of the instrument, the structure and assembly of the control die of the tractor, etc., in order to correctly grasp the extrusion process conditions, correct operate the machine.
The general operation steps for debugging are as follows:
(1) Before starting the machine, check whether the temperature control is sensitive, whether the instrument is out of order, whether the cooling water is unblocked, etc. Usually, thermometers and cooling water are used for detection.
(2) Heat the screw, barrel and die head of the extruder according to the operating procedures of the extruder. After the temperature rises to the set temperature, it must be kept warm for about 10 minutes before starting the machine, so that the temperature of each part of the machine tends to Stablize.
(3) Be sure to tighten the connecting screws and bolts of each part of the die head while it is hot before starting the machine. Before the material is extruded, the operator must not stand directly in front of the die to prevent the bolt or screw from breaking and causing injury.
(4) At the beginning of extrusion, the screw speed should be slow, and then gradually increased to prevent overloading and damage to the machine when starting.
(5) When starting up, add a small amount of material first, and keep the feeding balance. When feeding, pay close attention to various table values such as torque. After the material is extruded from the die and pulled by the traction device, the amount of material can be gradually increased until Extrude normally.
(6) When starting to pull, there should be a certain distance between the setting mold and the die head for easy pulling. Open the waterway (be careful not to pour water into the die head, otherwise it will cause abnormal discharge of the die head and lead to material breakage or mold blockage), the shape of the complex cavity is small and the profile of a mold with multiple cavities needs to open the cover plate of the shaping mold ;After confirming that the plasticization of the extruded material is normal, the material is pulled to the tractor through the set traction rope. Shorten the distance between the calibrating table and the die head, cover the cover, start the vacuum pump, wait until the extrusion speed and the pulling speed are basically balanced, observe the profile until the normal extrusion, and then shrink the distance between the calibrating table and the die head to the ideal value.
(7) If it is found that the parison is not formed at the entrance of the shaping die or the inner ribs are adhered to the inner cavity surface of the profile, use a pointed tool to poke several small holes on the unformed part of the parison or the inner ribs at the entrance of the first section of the shaping die. The hole makes the small cavity communicate with the atmosphere, and the parison is open when it enters the shaping mold, which is convenient for forming negative pressure and making the parison tightly adhere to the mold wall of the shaping mold.
(8) In case of blocked mold (unblocked), immediately move the setting table back or increase the traction speed, or implement the above two solutions at the same time, and then adjust the process to resume normal production. If it is blocked and the implementation of the above scheme is invalid, the shaping table should be moved back immediately, and the material should be cut off along the shaping die, the water vapor of the shaping die should be closed, the traction speed should be reduced, and the profile should be slowly pulled out from the shaping die. If part of the profile is broken in the calibrating mold, the calibrating mold needs to be disassembled and the residual material should be completely removed.
(9) When shutting down, it is generally necessary to add shutdown material first to squeeze out the production material in the machine, then stop the machine and disassemble the die head while it is hot for mold cleaning.
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Maintenance of extrusion die---
1. Improper loading, unloading or cleaning during maintenance and cleaning is one of the main reasons for damage to the mold. Therefore, the disassembly and cleaning of the mold should be done by professionals.
2. Copper parts should be used when disassembling and cleaning the die head.
3. The combined surface (sealing surface) of the die head can be cleaned with fine oil stone or metallographic sandpaper.
4. Before the mold is assembled, the flow channel should be polished to low roughness with metallographic sandpaper, and coated with a thin layer of organic silicon ester to reduce gas and water corrosion and protect the flow channel during long-term storage.
5. During the assembly process, all bolts, screw bearing surfaces and threads must be coated with high-temperature grease.
6. When dismantling the setting mold, care should be taken to avoid collision; when installing, it should be installed according to the sequence number of the template.
7. In the daily maintenance of the water tank, it should be ensured that there is an appropriate adjustment space on the four sides after the shaped block is installed.
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Extrusion Die Storage ---
1. The mold should be stored in a dry, clean and ventilated warehouse, and it is strictly forbidden to store it with corrosive products;
2. After the mold is used, it must be cleaned and reassembled. After the oil is sealed, it is stored in the warehouse;
3. Molds should be stored on special mold storage racks to ensure safe placement and easy access.
