What are the vulnerable parts of the sheet extrusion production line?

1. Extruder part
1. Screw:
During the long-term rotation and friction with the plastic particles, the surface of the screw will gradually wear. Especially when dealing with some high-hardness and high-filled plastic materials, the wear rate will accelerate. The worn screw will lead to problems such as decreased plasticization effect and unstable extrusion pressure, affecting the quality and production efficiency of the sheet.
For example, when producing sheets containing reinforcing materials such as glass fiber, the wear of the screw will be more obvious. The screw ridges may become blunt and the depth of the screw groove may become shallow, thereby affecting the conveying and plasticizing capacity of the plastic.
2. Barrel lining:
The barrel lining is in direct contact with the screw and the plastic melt, and is subjected to high temperature, high pressure and friction. After long-term use, the lining will have problems such as wear and corrosion. Severe wear will cause the gap between the barrel and the screw to increase, affecting the plasticization effect and extrusion stability.
For example, for some highly corrosive plastic materials, the barrel lining may be chemically corroded, resulting in surface peeling and thinning. At the same time, the plastic melt at high temperature will also cause certain thermal wear on the barrel lining.
3. Heating elements:
The heating elements of the extruder are usually in the form of resistance wires, heating rods, etc. Due to long-term high-temperature working conditions, the heating elements are prone to aging, circuit breakage and other problems. In addition, frequent heating and cooling cycles will also cause certain damage to the heating elements.
For example, the resistance wire may burn out due to long-term use, and the heating rod may experience surface oxidation and cracking. Once the heating element is damaged, it will affect the temperature control of the extruder, resulting in uneven plasticization of the plastic and affecting the quality of the sheet.
4. Filters and screen changers:
The filter is used to filter impurities and unmelted particles in the plastic melt to ensure the quality of the sheet. During the filtration process, the filter will gradually become clogged and need to be replaced regularly. The seals and moving parts of the screen changer are also prone to wear, affecting the efficiency and sealing of the screen changer.
For example, the filter may be clogged due to filtering a large amount of impurities, resulting in increased extrusion pressure. The seals of the screen changer may wear and leak due to frequent movement and high temperature environment.
2. Mold part
1. Die lip:
The die lip is a key component that determines the thickness and width of the sheet and is in direct contact with the plastic melt. During the long extrusion process, the die lip will be eroded and rubbed by the plastic melt, and it is easy to wear and deform. The worn die lip will cause problems such as uneven sheet thickness and uneven edges.
For example, the surface of the die lip may show signs of wear such as scratches and pits, affecting the surface quality of the sheet. At the same time, the deformation of the die lip may cause the width of the sheet to change, affecting the dimensional accuracy of the product.
2. Diverter shuttle and mandrel:
The diverter shuttle and mandrel are used to evenly distribute the plastic melt to various parts of the mold to ensure the uniformity of the sheet thickness. Under the action of high temperature and high pressure plastic melt, the diverter shuttle and mandrel will be subject to certain wear and corrosion. The worn diverter shuttle and mandrel will affect the flow uniformity of the plastic melt, resulting in quality problems such as uneven thickness and bubbles in the sheet.
For example, the surface of the diverter shuttle may be worn and corroded, affecting the diversion effect of the plastic melt. The core rod may become thinner due to long-term friction, affecting the inner diameter of the sheet.
3. Three-roll calender part
1. Roller surface:
The roller surface of the three-roll calender is in direct contact with the sheet to calender and cool the sheet. During long-term use, the roller surface will be rubbed and worn by the sheet, and scratches, pits and other problems may occur. In addition, the roller surface may be damaged by high temperature and chemical corrosion.
For example, scratches on the roller surface may cause indentations on the sheet surface, affecting the appearance quality of the sheet. Chemical corrosion may cause the chrome plating on the roller surface to fall off, affecting the service life of the roller.
2. Bearings and transmission parts:
The rollers of the three-roll calender are usually supported and driven by bearings and transmission parts. During long-term operation, the bearings and transmission parts will be subject to greater loads and friction, and are prone to wear, loosening and other problems. Worn bearings and transmission parts will affect the rotation accuracy and stability of the rollers, resulting in uneven thickness and uneven surface of the sheet.
For example, the bearings may wear due to long-term high-speed rotation, resulting in increased gaps and noise. The gears of the transmission parts may have poor meshing due to wear, affecting the transmission efficiency of the roller.
IV. Tractor part
1. Traction belt and chain:
The belt and chain of the tractor are used to pull the sheet out of the extruder and the die, and are subject to large tension and friction. During long-term use, the belt and chain will wear and elongate. Severely worn belts and chains will affect the stability and accuracy of traction, causing uneven stretching and deformation of the sheet.
For example, the belt may have surface cracks and thinning due to wear, and the chain may have problems such as increased pitch and looseness due to wear.
2. Clamping device:
The clamping device of the tractor is used to clamp the sheet on the belt or chain to ensure the stability of traction. The rubber pads, springs and other parts of the clamping device are prone to wear and aging, affecting the size and stability of the clamping force. The worn clamping device will cause the sheet to slide and deflect during the traction process, affecting the quality and production efficiency of the sheet.
For example, the rubber pad may wear out due to long-term friction, lose elasticity, and affect the clamping force. The spring may lose elasticity due to fatigue, resulting in insufficient clamping force.
V. Cutting device part
1. Cutting tool:
The cutting tool of the cutting device is used to cut the continuous sheet into the required length and width. During the cutting process, the cutting tool will be subjected to greater friction and impact force, and it is easy to wear and damage. The worn cutting tool will cause problems such as uneven cutting and reduced dimensional accuracy.
For example, the blade of the cutting tool may become blunt due to wear, affecting the cutting effect. The tool holder may loosen due to impact force, affecting the stability of the cutting tool.
2. Transmission parts:
The transmission parts of the cutting device are used to drive the cutting tool for cutting movement. During long-term operation, the transmission parts will be subjected to greater load and friction, and are prone to wear, looseness and other problems. The worn transmission parts will affect the movement accuracy and stability of the cutting tool, resulting in problems such as uneven cutting and reduced dimensional accuracy.
For example, the gears of the transmission parts may have poor meshing due to wear, affecting the movement speed and accuracy of the cutting tool. The transmission shaft may have increased clearance and shaking due to wear, affecting the stability of the cutting tool.