The correct and reasonable use of plastic extruder can give full play to the efficiency of the machine, maintain a good working condition, and extend the service life of the machine.
The use of screw extruder includes a series of links such as machine installation, adjustment, test run, operation, maintenance and repair. Its use has the common characteristics of general machines, mainly in the drive motor and speed reduction device. However, the working system of the screw extruder is the extrusion system, but it has unique characteristics. Pay special attention to its characteristics when using the screw extruder.
Operators must be familiar with the structural characteristics of the extruder they are operating, especially the structural characteristics of the screw, heating and cooling control instrument characteristics, head characteristics and assembly conditions, etc., in order to correctly grasp the extrusion process conditions and correct To operate the machine. The operating methods of extruding different plastic products are different, but there are also similarities. The following briefly introduces the same operation steps and matters needing attention when extruding various products.
(1) Plastic for extrusion molding. The raw materials should meet the required drying requirements, and further drying should be done if necessary. The raw materials are sieved to remove agglomerates and mechanical impurities.
(2) Check whether the water and electrical systems of the equipment are normal, to ensure that the water and gas path is unblocked and leak-free, whether the electrical system is normal, whether the heating system, temperature control, and various instruments are working reliably; the auxiliary machine is empty and the vehicle is tested at low speed, and observe Whether the equipment is operating normally; start the vacuum pump of the sizing table and observe whether it works normally; add oil to lubricate the lubricated parts of various equipment. If a fault is found, remove it in time.
(3) Install the head and sizing sleeve. According to the variety and size of the product, select the specifications of the machine head.
(1) You can drive after the constant temperature. Before starting, you should tighten the head and the flange bolts of the extruder again to eliminate the difference in thermal expansion between the bolts and the head. The order of tightening the head bolts is to tighten diagonally: Evenly. When tightening the flange nuts of the machine head, the surroundings must be tight, otherwise the material will run out.
(2) Drive Select and press the Ready to Drive button, then connect the Start button, and then slowly rotate the screw speed adjustment knob, the screw speed starts slowly. Then gradually speed up, while adding small amounts. Pay close attention to the indication changes of the host ammeter and various indicator heads when feeding. The screw torque cannot exceed the red mark (-generally 65% 75% of the torque meter). Before the plastic profile is extruded, no one is allowed to stand directly in front of the die to prevent injuries caused by bolts breaking or due to damp and foaming raw materials. After the plastic is extruded from the die, the extrudate needs to be slowly cooled and led to the traction device and the shaping die, and these devices are activated. Then according to the indicated value of the control instrument and the requirements for extruded products. Adjust each part accordingly to make the entire extrusion operation reach a normal state
In plastic extrusion molding equipment, the plastic extruder is usually called the main machine, and the subsequent equipment that is matched with it is called the auxiliary machine. After more than 100 years of development, the plastic extruder has been derived from the original single-screw, multiple-screw, multi-screw, and even screw-less models. The plastic extruder (host) can be used with various plastic molding auxiliary machines such as pipe, film, holding material, monofilament, flat wire, packing belt, extruded mesh, plate (sheet) material, profiled material, granulation, cable coating, etc. Matching to form various plastic extrusion molding production lines to produce various plastic products. Therefore, plastic extrusion molding machinery is one of the widely used models in the plastic processing industry, no matter now or in the future. Classification of extruders With the wide application and continuous development of plastic extrusion molding technology, the types of extruders are being updated day by day. There are mainly the following five types of classification methods.
1. According to the installation position, it can be divided into vertical extruder and horizontal extruder;
2. According to the purpose, it can be divided into extruder for forming, extruder for mixing and drawing and feeding extruder for feeding;
3. According to the number of screws, it can be divided into screwless extruder, single screw extruder, twin screw extruder and Double Screw Plastic Extruders
4. According to whether it is vented or not, it can be divided into vented extruder and non-vented extruder
5. According to the screw speed, it can be divided into ordinary extruder, High Speed Extruder and super high speed extruder.
1. The plastic extruder equipment should be placed in a ventilated position to ensure the heat dissipation of the motor and extend its life; the machine should be well grounded.
2. Regularly check the tool screws. After using the new machine for 1 hour, use tools to tighten the movable knife, the fixed knife screw, and the fixation between the tool holder: the bearing should be regularly filled with lubricant to ensure the lubricity between the bearings; In order to ensure the sharpness of the cutting tool, the tool should be checked frequently to ensure its sharpness and reduce unnecessary damage to other parts caused by the blunt blade; regularly check whether the belt is loose and adjust it in time.
3. Restart the strengthening blade before starting the second time, remove the remaining scraps in the machine room to reduce the starting resistance, open the inertia set and the pulley set regularly, and clear the ash outlet under the flange, which is discharged from the crusher chamber The powder enters the shaft bearing.
4. When replacing parts and changing tools, the gap between the movable knife and the fixed knife: 0.8MM for crushers above 20HP is better, and 0.5MM for crushers below 20HP is better. The thinner the recycled material, the larger the gap.