Daily use and maintenance of lab extruder

Plastic extrusion production line of all types of products, have their operating characteristics, the operation of a detailed understanding of their characteristics, can give full play to the effectiveness of the machine.
Extruder is one of the types of machine, grasp the operating points of the extruder, the correct use of the extruder. The use of screw extruder include machine installation, adjustment, commissioning, operation, maintenance and repair of a series of links, it has the general character of machine, mainly in the drive motor and slow speed changing device. However, the working system of the screw extruder is the extrusion system, but it has its own unique characteristics.
The installation, adjustment and commissioning of the machine are clearly specified in the instruction manual of the extruder:
The operating personnel must be familiar with the structure characteristics of the extruder for his own operation, especially to correctly grasp the structure characteristics of the screw, heating and cooling control instrument characteristics, head characteristics and assembly, in order to correctly master the processing conditions, correct operation of the machine. When making different plastic products, the operating points of the extruder are different, but also have the same. The following brief introduction of extrusion products of the same operating procedures and should pay attention to the operating points of the extruder.
1, the preparation before driving
(1) plastics for extrusion molding. The raw materials shall be in accordance with the requirements of drying and shall be further dried if necessary. The raw material is sieved to remove agglomerate particles and mechanical impurities.
(2) check the equipment of water, electricity and gas system is normal, ensure water, gas flow, leakage, electrical system is normal, heating system, temperature control, various instruments are reliable; auxiliary empty low-speed test run, to observe whether the normal operation of equipment; start the vacuum pump, observe whether normal; in all kinds of equipment lubrication parts lubrication. If the fault is found in time.
(3) head and set. According to the variety and size of the product, select the specification.
2, drive
(1) to drive at a constant temperature, before driving should be head and extruder flange bolts to tighten a bolt and the head, to eliminate the differences in thermal expansion, tight head bolt tightening sequence is diagonal, the force should be uniform. Tighten the flange nut, the requirements of the tightness around the same, or to run.
(2) drive, select "ready to drive" button, then take the "car" button, and then slowly rotating screw speed adjustment knob, screw speed slow start. Then gradually speed up, while a small amount of feeding. Pay attention to the change of the indicator of the current meter and all kinds of instructions when feeding. Screw torque should not exceed the red mark (usually 65%-75%). Before the plastic profile is extruded, no person shall stand at the front of the mouth mold to prevent damage to the bolt due to the breakage of the bolt or the raw material. When the plastic is extruded from the die, it is necessary to cool the extrudate slowly and lead the traction device and the molding die. According to the indication value of the control instrument and the requirements of the extrusion products. The parts are adjusted accordingly so that the whole extrusion operation is in a normal state. And according to the need to add enough material, double screw extruder adopts uniform metering feeder to feed.
(3) when the discharge is uniform and plastic can be good traction type a person set. The plasticizing degree judgment needs by experience, can be judged according to the extrusion material appearance, surface luster, no impurities, no foam, coke material and color, the extrusion extrusion fine to a certain extent without burr, split by hand, with certain elasticity, it indicates good plasticizing. If the plasticizing is bad, the screw speed, barrel and die temperature can be adjusted to meet the requirements.
(4) in the process of extrusion, the process parameters should be checked periodically according to the technical requirements, and fill in the process record. Check the quality of the product according to the quality inspection standard, find the problem and solve the problem.
3, parking
(1) stop feeding, extrude the plastic in the extruder, expose the screw, turn off the cylinder and the power supply of the head, stop heating.
(2) turn off the extruder and auxiliary power supply to stop the screw and the auxiliary machine.
(3) open the head connection flange and remove the head. Cleaning the various parts of the porous plate and the head. When cleaning to prevent damage to the head surface, the residual material application of copper inside the nose to clean up, and then the plastic adhesion in the die grinding and polishing with sandpaper, in addition, coated with oil or silicone oil rust.
(4) screw, barrel cleaning, removal of the head, restart the host, plus parking material (or broken material), cleaning screw, barrel, screw at this time to reduce wear and tear. To stop feeding ground3 completely after extrusion, compressed air from the feeding port, the exhaust port repeatedly blowing residual pellets and powders, until the barrel is indeed no residual material, screw speed drop to zero, stop the extruder, shut off the main valve and the total power of cold water.
(5) the safety items that should be paid attention to when extruding the extruder are: electrical, thermal, mechanical rotation and the loading and unloading of heavy components. The extruder must be equipped with lifting equipment, such as the installation of the head, screw and other heavy components to ensure safe production