Vacuum blow molding extruder screw barrel

Introduction:
The blow molding screw structure has ordinary type and high-yield type, and the length-diameter ratio is 24:1, 25:1, 28:1, 30:1, 32:1. The screw compression ratio is combined with the compression ratio of the parison head to meet the controllability of the material temperature during the extrusion process, the controllability of the material plasticization degree, and the stability of the material flow at the discharge end. Reasonable shearing and dispersing elements make the additives and materials more evenly kneaded, and the structures with different length-diameter ratios are different. For example, the separation screw: after many experiments, the secondary edge is drawn at a reasonable position, which can solve the gas impurities generated during the feeding, compression, and screw drying process. In order to adapt to the high-yield screw and powder feeding, the barrel feeding section is equipped with a slotted bushing and a strong cold water circulation to increase the friction and improve the pumping capacity of the screw.

The screw structure is suitable for
PE, PP, ABS, PET, PETG, PA, etc.
Applicable to the following models Special-shaped parts blow molding machine:
Chair back, base, pallet, car water tank, tool box, etc.
Urea, chemical stacking barrel machine
Daily chemical washing bottle blowing machine
Food and beverage bottle blowing machine
Highway facility blow molding machine

Installation process and precautions for blow molding machine screw barrel

1. Installation of barrel screw
2. First, before installation, the spare screw should be installed with the barrel in advance. In order to prevent the screw from sliding inside the barrel, do not remove the fixed lead wire first. For safety, you can clamp a small piece of wood in the middle of the feed port. Then hoist it to the original position of the barrel, fix it, and connect the storage head and the feed section.
3. After the barrel is installed, hoist the reducer back to the frame of the plastic blow molding machine. Before installation, add some grease to the reducer main shaft connecting sleeve and the screw handle to prevent rust and make it easier to disassemble next time. This part requires a special screw removal tool for installation. The screw handle of our company is made with installation screw holes. When installing, insert the screw into the inner hole of the reducer main shaft, screw the screw into the screw installation screw hole, and then align the keyway position of the reducer and the screw, and install the screw through the nut and pull it into the reducer.
4. After the previous step is completed, the next step is to connect the various parts. First, fix the bolts of the blow molding machine equipment and the reducer, install and fix the bolts of the reducer and the feeding section, connect the coupling and the extrusion motor, and install the heater and wiring. This step must ensure the correct installation and connection of each part.
5. The next step is to install the feeding device. First, check the connection of each wiring, bolts and blow molding machine equipment, and then heat the machine for testing.
6. When checking and repairing the extrusion motor, the grease of the reducer can be changed.
7. Precautions for the use of barrel screw
8. Each plastic has an ideal plasticizing processing temperature range, and the barrel processing temperature should be controlled to be close to this temperature range. Granular plastic enters the barrel from the hopper and first reaches the feeding section. Dry friction will inevitably occur in the feeding section. When these plastics are not heated enough and melt unevenly, it is easy to cause increased wear on the inner wall of the barrel and the surface of the screw. Similarly, in the compression section and homogenization section, if the molten state of the plastic is disordered and uneven, it will also cause increased wear. It is forbidden to rotate the screw when the temperature is seriously insufficient.
9. The speed should be properly adjusted. Because some plastics are added with reinforcing agents, such as glass fiber, minerals or other fillers. The friction of these substances on metal materials is often much greater than that of molten plastics. When extruding these plastics, if a high speed is used, while increasing the shear force on the plastic, the reinforcement will also produce more torn fibers accordingly. The torn fibers contain sharp ends, which greatly increases the wear force. When inorganic minerals slide on the metal surface at high speed, their scraping effect is also not small. Therefore, the speed should not be adjusted too high.
10. Remove debris from the plastic. Generally speaking, there is no debris in the fresh plastic purchased in its original packaging, but after transportation, weighing, drying, color mixing, and especially adding recycled materials, there may be debris mixed in. Small metal chips, large heating coils, nuts, paper clips, bolts, etc., mixed into the barrel, the damage to the screw is self-evident (of course, the barrel will also be damaged at the same time), and even the screw is stuck. Under strong torque, the screw breaks and the barrel flange top is deformed, so strict management and monitoring of feeding is required.
11. The moisture contained in the plastic has a certain effect on the wear of the screw surface. If the plastic is relatively damp, the moisture is not completely removed before extrusion. When the residual moisture enters the compression section of the screw, it forms “steam particles” with high temperature and pressure that are previously melted and mixed in the molten plastic. As the screw advances during the extrusion process, from the homogenization section to the screw head, these “steam particles” are decompressed and expanded during the extrusion process, like fine impurity particles, which have a frictional and destructive effect on the wall surface, and also have a great impact on the quality of the extruded product, and unstable feeding will also occur.