High speed, high efficiency, intelligence – the future of sheet extrusion
High speed, high efficiency, intelligence – the future of sheet extrusion
Compared with other molding methods, the extrusion molding of sheet material has the advantages of relatively simple equipment used in the production line, low input cost and high production efficiency. The process flow of sheet extrusion molding is as follows: the molten plastic is plasticized and extruded by the extruder and then enters the die through the grid plate. Now the flat die is widely used, which has a wide and thin outlet, and the molten material flows from the machine. From the barrel to the machine head, the runner changes from a circular shape to a slit shape (flat-slot shape), and the material will be evenly distributed along the width of the machine head. The sheet or sheet is extruded through the die, and the material flows through the entire die runner. The pressure is reduced to moderate, and the residence time is as short as possible, and no stagnation phenomenon occurs. Under the traction of the traction device, it is calendered by a smooth roller, then shaped by a trimming device, and finally cut into a product of the desired length by the cutting device.
The extrusion molding technology of plastic sheet will show the following development trends in the future
◆ Reduce labor and material consumption, mainly reflected in shortening the time for product replacement as much as possible, as much as possible in the production process and automatic replacement;
◆ Improve production efficiency by increasing the plasticizing capacity of the equipment, increasing the gear torque, and further increasing the length-diameter ratio of the screw;
◆ In extrusion molding, cooling has been limiting the improvement of productivity, and it is necessary to break through the cooling limit;
◆ Continuous application of induction measurement technology and artificial intelligence technology in the extrusion production line control system further improves the stability of sheet production and the quality of products.
What should be paid attention to when purchasing a sheet extruder?
The wide application of plastic products has promoted the rapid development of the plastic machine industry, and the extruder has an important position in the plastic machine industry. Extruders can be divided into single-screw, twin-screw and multi-screw extruders according to the number of screws. How to choose a satisfactory extruder and what to pay attention to when purchasing an extruder has always been a troubled problem for some users. Let’s take a look at what to pay attention to when purchasing an extruder.
Purchase point 1: screw speed
The speed of the screw is the most critical factor affecting the production capacity of an extruder. The screw speed not only affects the extrusion speed and extrusion volume of the material, but more importantly, it enables the extruder to obtain a good plasticizing effect while achieving high output. In the past, to increase the output of the extruder, the main method was to increase the diameter of the screw. Although the screw diameter increases, the material extruded per unit time will increase. But the extruder is not a screw conveyor. In addition to extruding the material, the screw also extrudes, stirs and shears the plastic to plasticize the plastic. On the premise that the screw speed remains unchanged, the screw with large diameter and large groove does not have as good a stirring and shearing effect on the material as the screw with small diameter.
Therefore, modern extruders mainly improve the production capacity and pipe quality by increasing the screw speed. If the screw diameter is unchanged and the screw speed is increased, the torque on the screw will increase. When the torque reaches a certain level, the screw is in danger of being twisted and broken. However, by improving the material and production process of the screw, rationally designing the screw structure, shortening the length of the feeding section, increasing the flow rate of the material, and reducing the extrusion resistance, the torque can be reduced and the bearing capacity of the screw can be improved.
Purchase point 2: screw structure
The screw structure is the main factor affecting the capacity of the extruder. If there is no reasonable screw structure, simply increasing the screw speed to increase the extrusion volume is against the objective law and will not be successful. The design of the high-speed and high-efficiency screw is based on high rotational speed. The plasticizing effect of this kind of screw will be poor at low speed, but the plasticizing effect will gradually improve after the screw speed is increased, and the best effect will be obtained when the design speed is reached. At this time, there is not only a higher production capacity, but also a qualified plasticizing effect.
Purchase point three: barrel structure
The improvement of the barrel structure is mainly to improve the temperature control of the feeding section and set the feeding trough. Whether the temperature of the water jacket is reasonable is very important for the stable operation of the extruder and efficient extrusion. If the temperature of the water jacket is too high, the raw material will be softened prematurely, and even the surface of the raw material particles will be melted, which will weaken the friction between the raw material and the inner wall of the barrel, thereby reducing the extrusion thrust and extrusion volume. However, the temperature should not be too low. If the temperature of the barrel is too low, the rotation resistance of the screw will be too large. When the bearing capacity of the motor is exceeded, the motor will be difficult to start or the rotation speed will become unstable. Bell Machinery uses advanced sensors and control technology to monitor and control the water jacket of the extruder, so as to automatically control the temperature of the water jacket within the optimal process parameter range.
Purchase Point 4: Accelerator
Under the premise that the structure is basically the same, the manufacturing cost of the reducer is roughly proportional to its overall size and weight. Because the shape and weight of the reducer are large, it means that a lot of materials are consumed during manufacturing, and the bearings used are also relatively large, which increases the manufacturing cost. The extruder with the same screw diameter, the high-speed and high-efficiency extruder consumes more energy than the conventional extruder, the motor power is doubled, and the frame size of the reducer is correspondingly increased. But high screw speed means low reduction ratio. For the same size reducer, the gear module of the low reduction ratio is increased compared with the large reduction ratio, and the load bearing capacity of the reducer is also increased.
Therefore, the increase of the volume and weight of the reducer is not linearly proportional to the increase of the motor power. If the extrusion volume is used as the denominator and divided by the weight of the reducer, the number of high-speed and high-efficiency extruders is small, and the number of ordinary extruders is large. In terms of unit output, the motor power of the high-speed and high-efficiency extruder is small and the weight of the reducer is small, which means that the machine manufacturing cost per unit of the high-speed and high-efficiency extruder is lower than that of the ordinary extruder.
In addition, the production cost, production efficiency, suppliers and operability of the extruder should be considered when purchasing.
What is the future development trend of plastic sheet equipment?
The gradual improvement of the domestic sheet machine manufacturing level has increased the increase of domestic production of plastic sheet enterprises and the diversification of sheet varieties, and also increased the prosperity of the thermoforming packaging industry. The development of my country’s sheet machine industry generally has the following trends:
The “vertical three-roller” sheet production line configured with a single “separated single-screw extruder” tends to be saturated. Most domestic thermoforming enterprises have this type of sheet production line, which enables enterprises to occupy the market and accumulate funds in advance. , Technology development has made great contributions. The sheet produced by it can basically meet the production requirements, but the sheet produced by it, especially the HIPS sheet, cannot produce satisfactory gloss, and the grade is low. This kind of sheet machine technology is quite mature, easy to assemble, easy to buy parts, simple configuration, simple operation, cheap, low maintenance costs, has become a more popular model. Intense competition has forced some sheet machine manufacturers to switch to other products. If the main energy has been put on the “development of aluminum-plastic composite panels”, it will move towards a better sheet production line.
Why many companies choose us？
Factory direct sales, more than 10 years of industry experience
Safe and stable, high efficiency and energy saving
Equipment sells well at home and abroad
