The installation, adjustment, and commissioning of the machine are generally clearly specified in the operating manual of the extruder. Here is a brief description of the operating methods, maintenance, and upkeep of the extruder:
1、 Operation method of extruder
Operators must be familiar with the structural characteristics of the extruder they are operating, especially to correctly grasp the structural characteristics of the screw, the control instrument characteristics of heating and cooling, the characteristics of the machine head, and the assembly situation, in order to correctly grasp the extrusion process conditions and operate the machine correctly. The operation methods for extruding different plastic products vary, but there are also similarities. The following is a brief introduction to the same operating steps and precautions when extruding various products.
1. Preparation before driving
(1) Plastic used for extrusion molding. The raw materials should meet the required drying requirements, and further drying is necessary. And sieve the raw materials to remove agglomerates and mechanical impurities.
(2) Check whether the water, electricity, and gas systems in the equipment are normal, ensure that the water and gas circuits are smooth and leak free, whether the electrical system is normal, and whether the heating system, temperature control, and various instruments are working reliably; Low speed test run of the auxiliary engine without load, observe whether the equipment is operating normally; Start the vacuum pump of the molding table and observe if it is working properly; Apply lubricating oil to the lubricating parts of various equipment. If any faults are found, they should be promptly resolved.
(3) Install the machine head and set the sleeve. Select the specifications of the machine head based on the variety and size of the product. Install the machine head in the following order.
① The machine head should be assembled together and installed as a whole on the extruder.
② Before assembling the machine head, the grease applied during storage should be wiped off, and the surface of the mold cavity should be carefully checked for scratches, scratches, and rust spots. Necessary polishing should be carried out, and then a layer of silicone oil should be applied to the surface of the flow channel.
③ Assemble the various plates of the machine head together in sequence, apply high-temperature grease to the threads of the bolts, and then screw in the bolts and flange plates.
④ Place the perforated plate between the machine head flanges to ensure that it is tightly pressed without overflowing.
⑤ Before tightening the fastening bolts of the connecting flange between the machine head and the extruder, the horizontal position of the die should be adjusted. The square head can be adjusted horizontally, while the circular head should be leveled with the bottom surface of the die based on the fixed model adhesive surface.
⑥ Tighten the connecting flange bolts, tighten the machine head fastening bolts, install the heating ring and thermocouple, and ensure that the heating ring is tightly attached to the outer surface of the machine head.
⑦ Install the set sleeve and adjust it in place, check if the center line of the host, set sleeve, and traction machine is aligned. After adjustment, tighten the fixing bolts. Connect the water pipes and vacuum pipes of the set sleeve.
⑧ Turn on the heating power supply and evenly heat the machine head and machine casing. Simultaneously open the inlet valves of the cooling water and exhaust vacuum pump at the bottom of the feeding hopper and the gearbox. When heating up, adjust the temperature of each section to 140 ℃ first, and hold it for 30-40 minutes when the temperature rises to 140 ℃. Then, raise the temperature to the normal production temperature. When the temperature rises to the required temperature for normal production, maintain it for about 10 minutes to stabilize the temperature of various parts of the machine before starting production. The duration of insulation varies depending on different models of extruders and types of plastic materials. Keep it warm for a period of time to ensure that the temperature inside and outside the machine is consistent, in order to avoid instrument indications