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Strategies for extending the life of the screw of the injection molding machine: key points of daily operation and maintenance
2025-01-08
In the injection molding production workshop, the screw of the injection molding machine is as critical as the heart. After long-term continuous operation, screw wear problems occur from time to time.However, in addition to the helpless act of replacing when the wear is severe, through reasonable daily operation and careful maintenance, the service life of the screw can be greatly extended to ensure the stability and efficiency of production.
1. Screw speed: precise control is the key
The speed of the screw directly affects the shear rate and plasticization efficiency of the plastic in the barrel.While meeting the needs of production efficiency, it is necessary to avoid accelerating screw wear due to excessive speed.For common general-purpose plastic injection molding, the screw speed can be set between 80-150rpm in the initial stage according to the material characteristics.However, as production continues, close attention should be paid to the heating of the screw and the plasticization quality of the processed plastic.If the screw temperature is found to increase abnormally, or the product has appearance defects caused by uneven plasticization, such as flow patterns, air bubbles, etc., the screw speed should be moderately reduced in time, and each adjustment should be 10-20rpm.When processing high-viscosity materials such as engineering plastics, the speed should be strictly controlled. It is recommended that the starting speed be set at 30-80rpm to prevent damage to the surface of the screw due to excessive shear force, and treat every adjustment of the screw speed as if it is a precision gear. Fine adjustment.
2. Back pressure setting: optimize balance and seek long-term
Back pressure plays an important role in the compaction and mixing of plastics in the injection molding process, but unreasonable back pressure will also bring additional burden to the screw.In daily operation, for general plastics, the back pressure can be set in the range of 5-10MPa first.However, when producing products with high mixing uniformity requirements, such as plastic products containing masterbatch or additives, in order to ensure the full fusion of the materials, the back pressure can be appropriately increased to 10-15Mpa.However, it is important to remember that after increasing the back pressure, the torque changes of the screw should be observed synchronously. If the torque continues to increase and approaches or exceeds the rated value of the equipment, the back pressure must be adjusted immediately to avoid the screw from bending, deformation and other signs of wear due to excessive force, and always seek the best balance between quality and screw life.
3. Barrel cleaning: perform regularly to ensure smoothness
Regular cleaning of the barrel is an important line of defense to prevent screw wear.With the accumulation of production batches, a layer of residual plastic will be attached to the inner wall of the barrel, and these residues will gradually carbonize at high temperatures, forming hard fouling.Not only will it affect the plasticizing effect of the plastic, resulting in fluctuations in product quality, but it will also intensify the friction between the screw and the barrel.It is recommended to formulate a reasonable cleaning plan according to the type and production frequency of the processed plastics.For the continuous production of the same kind of plastic and the output is large, the barrel is cleaned at least once a week; if the plastic varieties are replaced frequently, it will be cleaned every 2-3 days of production.When cleaning, a professional barrel cleaner can be used to operate in accordance with the instructions, and the screw can be extracted to completely remove the dirt from the inner wall of the barrel and the surface of the screw, so that the screw can run smoothly in a clean environment and reduce unnecessary wear and tear.
4. Material management: source control and consumption reduction
Controlling the quality of materials from the source is of great significance to extend the life of the screw.In the procurement of raw materials, it is important to ensure the purity and quality stability of plastic particles, and avoid mixing with impurities, such as metal shavings, sand and gravel.During the rotation of the screw, these tiny impurities continuously scratch the surface of the screw like sandpaper, causing scratches, which in turn accelerates wear.In terms of material storage, moisture-proof and sun-proof measures should be taken to prevent the plastic from clumping due to moisture or aging due to light, which affects the plasticizing performance and indirectly increases the working load of the screw.Before feeding to the barrel, carefully check the state of the material. If there is agglomeration, it needs to be broken first to ensure that the material enters the barrel evenly and smoothly, and creates good working conditions for the screw.
5. Shutdown and maintenance: meticulous screw protection
The maintenance work during the shutdown of the injection molding machine cannot be ignored.After each shutdown, don't rush to power off. Let the screw run at low speed for 5-10 minutes to evenly distribute the remaining plastic on the surface of the screw to avoid local accumulation and hardening.Then, take out the screw while it is hot, dip an appropriate amount of special detergent in a soft cloth, gently wipe the surface of the screw to remove the attached plastic and oil stains, and then apply a thin layer of protective oil to prevent the screw from rusting.At the same time, check the nozzle at the front end of the barrel, the anti-reverse ring and other parts that closely match the screw, and if there is any wear or deformation, replace it in time to ensure that the screw can work accurately and smoothly the next time it is turned on, and guard every operation of the screw from the subtleties.
Through precise control of screw speed and back pressure in daily operations, regular cleaning of the barrel, strict management of materials and meticulous maintenance during downtime, the service life of the screw of the injection molding machine will be significantly extended, saving a lot of costs for enterprises and ensuring the continuous prosperity of injection molding production.
1. Screw speed: precise control is the key
The speed of the screw directly affects the shear rate and plasticization efficiency of the plastic in the barrel.While meeting the needs of production efficiency, it is necessary to avoid accelerating screw wear due to excessive speed.For common general-purpose plastic injection molding, the screw speed can be set between 80-150rpm in the initial stage according to the material characteristics.However, as production continues, close attention should be paid to the heating of the screw and the plasticization quality of the processed plastic.If the screw temperature is found to increase abnormally, or the product has appearance defects caused by uneven plasticization, such as flow patterns, air bubbles, etc., the screw speed should be moderately reduced in time, and each adjustment should be 10-20rpm.When processing high-viscosity materials such as engineering plastics, the speed should be strictly controlled. It is recommended that the starting speed be set at 30-80rpm to prevent damage to the surface of the screw due to excessive shear force, and treat every adjustment of the screw speed as if it is a precision gear. Fine adjustment.
2. Back pressure setting: optimize balance and seek long-term
Back pressure plays an important role in the compaction and mixing of plastics in the injection molding process, but unreasonable back pressure will also bring additional burden to the screw.In daily operation, for general plastics, the back pressure can be set in the range of 5-10MPa first.However, when producing products with high mixing uniformity requirements, such as plastic products containing masterbatch or additives, in order to ensure the full fusion of the materials, the back pressure can be appropriately increased to 10-15Mpa.However, it is important to remember that after increasing the back pressure, the torque changes of the screw should be observed synchronously. If the torque continues to increase and approaches or exceeds the rated value of the equipment, the back pressure must be adjusted immediately to avoid the screw from bending, deformation and other signs of wear due to excessive force, and always seek the best balance between quality and screw life.
3. Barrel cleaning: perform regularly to ensure smoothness
Regular cleaning of the barrel is an important line of defense to prevent screw wear.With the accumulation of production batches, a layer of residual plastic will be attached to the inner wall of the barrel, and these residues will gradually carbonize at high temperatures, forming hard fouling.Not only will it affect the plasticizing effect of the plastic, resulting in fluctuations in product quality, but it will also intensify the friction between the screw and the barrel.It is recommended to formulate a reasonable cleaning plan according to the type and production frequency of the processed plastics.For the continuous production of the same kind of plastic and the output is large, the barrel is cleaned at least once a week; if the plastic varieties are replaced frequently, it will be cleaned every 2-3 days of production.When cleaning, a professional barrel cleaner can be used to operate in accordance with the instructions, and the screw can be extracted to completely remove the dirt from the inner wall of the barrel and the surface of the screw, so that the screw can run smoothly in a clean environment and reduce unnecessary wear and tear.
4. Material management: source control and consumption reduction
Controlling the quality of materials from the source is of great significance to extend the life of the screw.In the procurement of raw materials, it is important to ensure the purity and quality stability of plastic particles, and avoid mixing with impurities, such as metal shavings, sand and gravel.During the rotation of the screw, these tiny impurities continuously scratch the surface of the screw like sandpaper, causing scratches, which in turn accelerates wear.In terms of material storage, moisture-proof and sun-proof measures should be taken to prevent the plastic from clumping due to moisture or aging due to light, which affects the plasticizing performance and indirectly increases the working load of the screw.Before feeding to the barrel, carefully check the state of the material. If there is agglomeration, it needs to be broken first to ensure that the material enters the barrel evenly and smoothly, and creates good working conditions for the screw.
5. Shutdown and maintenance: meticulous screw protection
The maintenance work during the shutdown of the injection molding machine cannot be ignored.After each shutdown, don't rush to power off. Let the screw run at low speed for 5-10 minutes to evenly distribute the remaining plastic on the surface of the screw to avoid local accumulation and hardening.Then, take out the screw while it is hot, dip an appropriate amount of special detergent in a soft cloth, gently wipe the surface of the screw to remove the attached plastic and oil stains, and then apply a thin layer of protective oil to prevent the screw from rusting.At the same time, check the nozzle at the front end of the barrel, the anti-reverse ring and other parts that closely match the screw, and if there is any wear or deformation, replace it in time to ensure that the screw can work accurately and smoothly the next time it is turned on, and guard every operation of the screw from the subtleties.
Through precise control of screw speed and back pressure in daily operations, regular cleaning of the barrel, strict management of materials and meticulous maintenance during downtime, the service life of the screw of the injection molding machine will be significantly extended, saving a lot of costs for enterprises and ensuring the continuous prosperity of injection molding production.
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