Preparation before start-up
(1) plastics for extrusion molding. Raw materials shall meet the required drying requirements, and further drying is required if necessary. The raw materials shall be sieved to remove agglomerates and mechanical impurities.
(2) Check whether the water, electricity and gas systems of the equipment are normal, ensure that the water and gas circuits are unblocked without leakage, whether the electrical system is normal, and whether the heating system, temperature control and various instruments work reliably; Conduct low-speed test run of the auxiliary machine with no load, and observe whether the equipment operates normally; Start the vacuum pump of the sizing table and observe whether it works normally; Lubricate the lubricating parts of various equipment. If any fault is found, it shall be eliminated in time.
(3) Installation head and setting sleeve. Select the machine head specification according to the product variety and size. Install the machine head in the following order.
① The heads of pipe extrusion machinery shall be assembled together and installed on the extrusion machinery as a whole.
② Before assembling the machine head, wipe off the grease applied during storage, carefully check whether there are bumps, scratches and rust spots on the surface of the cavity, polish it if necessary, and then apply a layer of chain oil on the surface of the runner.
③ Assemble each plate of the machine head in sequence, apply high-temperature grease on the bolt thread, and then screw on the bolt and flange.
④ Place the perforated plate between the machine head flanges to ensure that the perforated plate is pressed without overflow.
⑤ Before tightening the fastening bolts of the connecting flange between the die and the extrusion machine, the horizontal position of the die shall be adjusted. The level of the square die can be adjusted by the level, and the round die shall be leveled by the bottom of the die based on the rubber bottom of the stereotyped model.
⑥ Tighten the connecting flange bolts, tighten the head fastening bolts, install the heating ring and thermocouple, and note that the heating ring should be close to the outer surface of the head.
⑦ Install the sizing sleeve and adjust it in place. Check whether the main machine, the sizing sleeve and the middle line of the tractor are aligned. Tighten the fixing bolts after adjustment. Connect each water pipe and vacuum pipe of the sizing sleeve.
⑧ Turn on the heating power supply to heat the machine head and the machine Jane evenly. Open the cooling water at the bottom of the hopper and the gear box and the water inlet valve of the exhaust vacuum pump. During heating, the temperature of each section shall be adjusted to 140 ° C first, and then the temperature shall be kept for 30-40min when the temperature rises to 140 ° C, and then the temperature shall be increased to the temperature during normal production. When the temperature rises to the temperature required for normal production, it shall be maintained for about 10min to stabilize the temperature of all parts of the machine before starting production. The length of heat preservation time varies according to different types of plastic pipe extrusion machinery and plastic raw materials. Heat preservation for a period of time to make the internal and external temperatures of the machine consistent, so as to avoid that the instrument indicates that the temperature has reached the required temperature, but the actual temperature is low. At this time, if the material is put into the extrusion machine, because the actual temperature is too low and the melting viscosity of the material is too high, the axial force will be overloaded and the machine will be damaged.
⑨ Feed the raw materials for start-up into the hopper for use.
