Brief Description:The parallel screw industrial extruder consists of several parts including the transmission device, feeding device, barrel, and screws. The functions of each component are similar to those in a single-screw extruder, as shown in Figure 1. The difference from a single-screw extruder is that the twin-screw extruder has two parallel screws placed within a barrel with an "∞" shaped cross-section.
Parallel Screw Industrial ExtruderIntroduction:
One of the types of plastic machinery, originating in the 18th century. According to the angle between the material flow direction and the screw centerline, the die can be classified into right-angle dies and oblique-angle dies, etc. It relies on the pressure and shear force generated by the rotation of the screw, allowing the material to be fully plasticized and uniformly mixed, and then shaped through the die.
All technological advancements in twin-screw extruders are mainly concentrated in the transmission and extrusion sections. Only by integrating core hardware technology with core software technology can a cost-effective and competitive modern co-rotating twin-screw extruder be created.
The twin-screw extruder mainly consists of two major parts: the transmission part and the extrusion part.
1. The drive section provides torque to the screw, and strong torque output is the guarantee for the efficient operation of the twin-screw extruder; the extrusion section mainly consists of the barrel, screw elements, and core shaft, where the material completes plasticization, mixing, and extrusion.
All of its technological advancements are also concentrated in these two parts, constituting the hallmark of the updates and iterations of twin-screw extruders.
Compared to other models, one of its major features is the difference in the drive system. It requires evenly distributing power to two screws within a confined space, which is known as torque distribution technology. Different torque distribution technologies determine the load capacity of the gearbox and even directly affect the lifespan and performance of the entire machine.
The extrusion section is mainly composed of the barrel, screw elements, and core shaft, serving as the functional area for plasticization and mixing in a twin-screw extruder. The screw clearance, volume ratio, rotational speed, strength of the core shaft, and the lifespan of the screw elements are key indicators for evaluating the performance of the extrusion section of a twin-screw extruder.
Features:
It has a wide range of applications and can be used for processing various materials.
2. Gain a direct understanding of the wear condition of consumable parts; since it is easy to open, the degree of wear on the screw elements and the barrel liner can be detected at any time, allowing for effective maintenance or replacement.
3. It possesses all the advantages of traditional equipment, achieving high output, high quality, and high efficiency.
4. Reduce production costs; when changing colors, the barrel can be quickly opened in just a few minutes for manual cleaning, thus reducing or eliminating the need for cleaning materials and saving costs.
5, High torque, high speed. Currently, the development trend of twin-screw granulation equipment is towards high torque, high speed, and low energy consumption, with high speed bringing about high productivity.
6. Improve labor efficiency: when repairing the equipment, traditional machines often require the removal of the heating and cooling systems first, followed by the complete extraction of the screw. However, with a split twin-screw design, this is not necessary. By simply loosening a few bolts and turning the worm gear box handle to lift the upper half of the barrel, the entire barrel can be opened for maintenance. This not only reduces the maintenance time but also decreases the labor intensity.
Common Issues and Solutions for Parallel Screw Industrial Extruders:
The main motor cannot start
1. Cause of occurrence:
Start-up procedure error.
(2) The main motor thread has an issue, communication fault
(3) The interlock device associated with the main motor is activated.
2. Treatment methods:
(1) Check the procedure and restart the machine in the correct sequence.
(2) Check the main motor circuit.
(3) Check if the lubricating oil pump has started, and inspect the status of the interlock devices related to the main motor; if the oil pump is not on, the motor cannot be started.
(4) Check if the emergency button has been reset.
II. Unstable main motor current
1. Cause of occurrence:
Feeding is uneven.
(2) A certain heater has malfunctioned and is not heating.
(3) The screw adjustment pad is incorrect, or the phase is incorrect, causing component interference.
2. Treatment methods:
Check the feeder and troubleshoot.
(2) Check if all heaters are functioning properly, and replace them if necessary.
(3) Inspect the adjustment shims, pull out the screw to check for any interference.
III. The starting current of the main motor is too high
1. Cause of occurrence:
Insufficient heating time, high torque.
(2) A certain heater is not working.
2. Processing methods:
Before starting, the machine should be turned by hand. If it does not turn easily, extend the heating time or check if each section of the heaters is working properly.
IV. Poor discharge or blockage at the die head
1. Cause of occurrence:
The heater in a certain section is not working, leading to poor plasticization of the material.
(2) The operating temperature is set too low, or the molecular weight distribution of the plastic is wide and unstable.
(3) There may be foreign objects that are not easily melted.
2. Processing methods:
Check the heater and replace if necessary.
(2) Verify the set temperatures for each section, and if necessary, consult with the process engineer to increase the temperature settings.
(3) Clean and inspect the extrusion system and die head.
V. Unstable Head Pressure
1. Cause of occurrence:
The main motor speed is uneven.
(2) The feeding motor speed is uneven, causing fluctuations in the feeding amount.
2. Treatment methods:
Check the main motor control system and bearings.
(2) Check the feeding system motor and control system.
VI. Low lubricating oil pressure, oil pump alarm
1. Cause of occurrence:
Insufficient lubricating oil.
(2) Pipeline blockage, the filter has not been cleaned on a regular basis.
(3) Oil pump damage
2. Treatment methods:
Check and add the correct grade of gear oil.
(2) Check the oil lines and filters and clean them.
(3) Check the oil pump and replace if necessary
VII. The nylon pin is cut off
1. Cause of occurrence:
The torque of the extrusion system is too high.
(2) The main motor and the input bearing are not concentric.
2. Processing Methods:
(1) Check if any metal or other objects have entered and jammed the screw in the extrusion system. When this first occurs, check whether the preheating warm-up time or temperature increase values meet the requirements.
(2) Adjust the main motor.
Extrusion output suddenly decreases
1. Cause of occurrence:
The feeding system has malfunctioned or there is no material in the hopper.
(2) The extrusion system jams the screw, preventing the material from passing through.
2. Processing Methods:
Check the material level in the feeding system or hopper.
(2) Inspect and clean the extrusion system.
Nine, inaccurate temperature control
Causes of occurrence
The temperature controller is not functioning properly.
(2) The thermocouple is not in good contact
(3) The cooling system is not functioning properly.
2. Treatment Methods
Check the temperature control meter's wiring and parameters, and if necessary, perform auto-tuning or replace the instrument.
(2) Check if the thermocouple is in good contact
(3) Check if the corresponding solenoid valves are operating normally, and ensure that the water flow is unobstructed.
10. Insufficient vacuum or not functioning
Causes of occurrence
Vacuum pump failure
(2) Pipe leakage, blockage
(3) The material has not formed a closed cavity
2. Treatment Methods
(1) Check the vacuum pump and ensure that the circulating water is flowing smoothly. The exhaust pipe should not be reduced in size.
(2) Check for any leaks or blockages in the pipelines, and if necessary, disassemble and reinstall. Pay special attention to the seals.
(3) Check if gas is being sucked in at the opening position, and modify the screw structure if necessary.
Eleven, sudden power failure when the extruder is operating normally
Treatment method:
Immediately turn off the main switch of the extruder, and manually rotate the extruder motor by hand or with a crank to discharge as much material from inside the extruder as possible, minimizing the residue in the screw barrel. If the main motor of the extruder is directly connected to the gearbox and there is no mechanism for cranking the motor, you can also increase the cooling water of the cooling system to rapidly cool down the screw barrel and screw, preventing the material in the extruder from aging.
Nanjing Xintuo Intelligent Equipment Co., Ltd. was established on May 29, 2020, with Zhou Xianting as the legal representative. The registered capital is 10 million RMB, and the unified social credit code is 91320113MA21LF2H92. The company is located in the Baima Town Industrial Concentration Zone, Lishui District, Nanjing City. It belongs to the other manufacturing industry. Its business scope includes: Permitted projects: import and export of goods; import and export of technology (projects that require approval by relevant departments can only be carried out after obtaining such approval, specific business items are subject to the approval results). General projects: sales of intelligent material handling equipment; research and development of machinery and equipment; general equipment manufacturing (excluding special equipment manufacturing); specialized equipment manufacturing (excluding licensed specialized equipment manufacturing); sales of metal products; wholesale of electronic components; sales of instruments and meters; sales of artificial intelligence hardware; processing and sales of mechanical parts and components; general component manufacturing; sales of plastic products; production and sales of Class I medical devices; sales of Class II medical devices; sales of health supplies and disposable medical supplies; sales of special labor protective equipment; technical services, technical development, technical consultation, technical exchange, technology transfer, and technology promotion (except for projects that require approval, activities can be conducted independently according to the business license). The current operating status of Nanjing Xintuo Intelligent Equipment Co., Ltd. is active (in operation, open, registered).
