Due to improper operation or inadequate maintenance, the balancing machine may encounter many problems during use; Sometimes our technical after-sales personnel go to the customer's site and find that the problems that need to be solved are not difficult, mainly because there is not a person present who is familiar with the operation of the balancing machine. It's not enough to just know the basic operation of the balancing machine. It's also important for the operator to understand the daily maintenance of the balancing machine, the correct operation of the switch on and off, and the precautions during operation.
1、 Fault diagnosis and analysis of common abnormal phenomena in balancing machines.
1. Most measuring systems of dynamic balancing machines have a "self check" function, which can detect whether the measuring system itself is normal. The operation buttons corresponding to the "self check" function may be labeled as "self check" or "TEST". Users can fix various set support conditions (such as support method, a, b, c, and two radii) when the balancing machine is normal, and then put the measurement system into a "self check" state, recording the displayed readings of the "self check" state corresponding to this support condition. When the operator believes that there is a problem with the measurement system, they can restore the measurement system to the "self check" state corresponding to the original set support conditions, and then check whether the display reading of the measurement system is normal.
2. The angle of the imbalance displayed by the dynamic balancing machine is generally around 180 degrees or 0 degrees different. Firstly, confirm that the balancing machine is operating normally and the rotor still has a certain amount of residual imbalance (it is even possible to add two different phases of imbalance to the rotor on two counterweight surfaces). Under the condition of normal rotor rotation measurement, unplug the plug of sensor 1 wire and check if there is any change in the displayed value on the instrument. If there is a significant change, it indicates that the sensor wire and everything are normal. If there is no change, it indicates that there is a problem with the sensor wire or sensor. Insert the No.1 plug and then unplug the No.2 sensor wire plug. The same method can be used to determine whether the No.2 sensor wire and sensor are functioning properly. Users can find professionals to repair faulty sensor wires or sensors by comparing them to another sensor wire and sensor.
3. When the residual imbalance of the dynamic balancing machine is large, the fault is not obvious. But when the residual imbalance is small, the angle displaying the imbalance value always changes when starting the balancing machine for measurement. Sometimes the angle changes within a certain range, and sometimes the angle changes within a 360 degree range.
① To reduce interference from the same frequency, double frequency, and division frequency, the diameter of the workpiece support shaft should avoid being the same or close to the outer diameter of the support roller or its integer multiples to avoid interference. For example, if the outer diameter of the roller is 101 millimeters, it is best to avoid using shaft diameter supports within the range of 91-111, 46-55, and 32-36 millimeters.
② Strictly check the stability of the rotor assembly part. If using a process shaft, emphasis should be placed on checking the fit between the shaft and the hole.
③ Check the condition of the contact between the rotor shaft (process shaft) and the roller. If the shaft diameter is rough, the blade pattern is obvious, or the surface of the roller is damaged, it can cause instability during small signals.
④ Check the condition of the contact between the roller and the rotor shaft (process shaft). If the continuous and smooth outer surface on the roller contact surface has been damaged, it can also cause instability during small signals. When there are obvious scars on the contact surface of the roller, the display of balance is very unstable.
⑤ Clean the contact surface between the roller and the rotor shaft (process shaft) while parking, and add an appropriate amount of lubricating oil.
⑥ Carefully calculate if your balance accuracy requirements are too high.
4. When the residual imbalance of the dynamic balancing machine is large, the fault is not obvious. But when the residual imbalance is small, the angle displayed for the imbalance value always changes by approximately 180 degrees when the measurement is restarted after each balancing.
① The balance amount provided is too high.
② Strictly check the stability of the rotor assembly part. If using a process shaft, it is important to strictly check the clearance, ovality, and taper errors between the mating shaft and the hole, especially the ovality and taper errors.
2、 Four point fault diagnosis
After the above methods of inspection and maintenance are completed, if the fault still exists, the dynamic balancing machine can be inspected using the four point inspection method introduced below. In general, users can use a physical rotor according to this. If necessary, users can record the following process and all data, and then provide them to the manufacturer of the balancing machine. The manufacturer can determine more than 90% of faults based on this record.
1. Firstly, balance the rotor to the highest possible accuracy, and then prepare a detachable counterweight block that is 30-50 times greater than the residual unbalance of the rotor (the following process is as follows: use a counterweight block weighing 100 grams, and the residual unbalance of the rotor should be less than 2-3 grams). The connection and loading form between the rotor and the balancing machine remain unchanged, and proceed directly to the following test process.
2. Check whether the various settings of the dynamic balancing machine are normal.
3. Add a known weight counterweight that can be disassembled at 45 degrees around the designated counterweight circumference on either side of the rotor (assuming a counterweight weight of 100 grams below). Start the dynamic balancing machine, and the indicated values on the corresponding surface of the balancing machine should be between 40-50 degrees and 90-110 grams (according to a weight removal rate of 90%).
4. After stopping the machine, remove the counterweight and install it at a 135 degree angle around the same circumference of the rotor. Start the balancing machine, and the indicated values on the corresponding surface of the balancing machine should be between 130-140 degrees and 90-110 grams (based on a weight removal rate of 90%).
5. After stopping the machine, remove the counterweight and install it at a 225 degree angle around the same circumference of the rotor. Start the balancing machine, and the indicated values on the corresponding surface of the balancing machine should be between 220-230 degrees and 90-110 grams (based on a weight removal rate of 90%).
6. After stopping the machine, remove the counterweight and install it at a 315 degree angle around the same circumference of the rotor. Start the balancing machine, and the indicated values on the corresponding surface of the balancing machine should be between 310-320 degrees and 90-110 grams (based on a weight removal rate of 90%).
7. In the same process, install this counterweight block at four angles around the designated counterweight circumference on the other side of the rotor for inspection.
8. If the dynamic balancing machine can meet the above requirements, it is considered that there is no fault with the balancing machine.
9. If the dynamic balancing machine can approximately meet the above requirements, it is considered that there is a slight inaccurate calibration problem with the balancing machine. This issue generally leads to a decrease in operational efficiency without causing major operational errors.
If there is a slight issue of inaccurate calibration in the dynamic balancing machine, users can eliminate it according to the supporting manual of the balancing machine, or notify the manufacturer to handle it.
10. If the dynamic balancing machine does not meet the above requirements and the error is very large, the user should notify the manufacturer for handling.
11. In special circumstances, when users have doubts about the accuracy or quality of the balancing machine, they can also perform four-point fault diagnosis on the balancing machine.
Sometimes users may find that the rotor has already achieved balance accuracy on the balancing machine. Through the above methods, it is believed that the balancing machine is also functioning normally. However, during the actual installation and operation of the rotor, there is still a certain degree of vibration. At this point, it is necessary to carefully analyze other technological reasons.
Balancing machine manufacturer
3、 Carefully analyze the cause of vibration and correctly determine the true balance accuracy
There are many reasons for mechanical vibration, among which the vibration caused by the balance problem of rotating components is the most direct. But this does not mean that after the rotor is balanced on the balancing machine, all vibration problems can be solved.
The imbalance problem of the rotor is caused by the deviation of the center of gravity from the geometric centerline of the rotor's rotation. The centrifugal force generated by the rotation of the rotor rotates with the rotor, thereby stimulating vibration of the rotor and its installation foundation (such as bearing seat, frame, chassis, vehicle body, etc.).
The following will discuss some process issues related to balancing machines.
1. Process issues with the dynamic balancing machine itself
When balancing with high precision, the influence of related connectors such as universal couplings and keys should be considered. The balancing process of small rotors requires the addition of auxiliary masses such as cursors, and also needs to consider their impact on the final balancing accuracy. When the imbalance caused by these related connections is close to or even greater than the rotor balance accuracy required by the user, the imbalance displayed by the balancing machine is unreliable. For balancing machines driven by universal couplings, the balance accuracy of the universal coupling should also be regularly checked.
When using a process shaft for balance, the circular runout of the process shaft cannot exceed the rotor balance accuracy index e (eccentricity), otherwise it must be flipped 1800 for high-precision balance. Alternatively, scrap the process shaft.
In addition, the structure of the process shaft and the actual installation shaft of the rotor should be made as consistent or similar as possible to ensure that its mass distribution is consistent with the actual installation state.
2. Process issues with the rotor
Users of dynamic balancing machines should try to balance the rotor in its true installation state and ensure its rigidity.
When using a process shaft for balancing, there is an error between the process shaft and the actual installation shaft of the rotor, such as the different installation methods, keyway structures, and the respective jumps of the process shaft and the actual shaft on the process shaft. These factors can all cause changes in the imbalance amount.
When using a process shaft for balancing, it is necessary to ensure the dimensional accuracy and positional tolerance accuracy of the rotor installation hole, such as large fit clearance, elliptical or tapered hole errors, low roughness, etc., which are absolutely not allowed.
In addition, the rigidity of the rotor must be ensured. If there are sliding splines, movable blocks, swinging knife blocks, and other similar structures inside the rotor, such a rotor will never achieve the ideal balance accuracy.
3. Process issues during the actual installation of the rotor
The rotor has already achieved the required balance accuracy on the balancing machine. If some factors are not carefully considered during the actual installation and operation of the rotor, it will still cause changes in balance accuracy and even cause a certain degree of vibration.
The first factor is the actual installation shaft runout, which is very important. Because of the imbalance problem of the rotor, it is due to the deviation of the center of gravity from the geometric centerline of the rotor's rotation. The centrifugal force generated by the rotation of the rotor rotates with the rotor, thereby stimulating vibration of the rotor and its installation foundation. The installation of a balanced rotor on an eccentric actual installation shaft will naturally cause vibration of the rotor and machine.
In addition, other components that are coaxial with the rotor can also cause vibration of the rotor and machine, such as pulleys, couplings, motor rotors, etc. Their balance accuracy will also participate in the vibration of the machine together with the rotor.
Balancing Machine Company
4. Other issues
Our company's technical personnel found during after-sales service that some balance machine users did not pay attention to the early manufacturing quality of their products during the production process, and relied entirely on the dynamic balance process for the rotor's operational performance. This is very serious.
For example, in product design, the processability of the dynamic balance process is not considered;
The basic components of the product (such as brackets) are cut corners and even have serious defects;
Excessive end face runout of the fan rotor or other welded structure rotors;
The uneven mass distribution of the casting rotor has a large error;
The installation hole accuracy and roughness of the rotor are too low;
There are serious non rigid factors in the internal structure of the rotor (such as missed welding, loose rivets, etc.);
The roughness and accuracy of the process shaft are too low;
The actual installation accuracy and roughness of the rotor shaft are too low, etc,
All these factors can lead to a decrease in balance accuracy or even balance failure.
In addition, the dynamic balancing machine belongs to the instrument testing machine product category. Rough operations on the balancing machine (such as welding, sanding, etc.) can also directly affect the performance and lifespan of the balancing machine, leading to balancing failure. Please be careful.
1、 Fault diagnosis and analysis of common abnormal phenomena in balancing machines.
1. Most measuring systems of dynamic balancing machines have a "self check" function, which can detect whether the measuring system itself is normal. The operation buttons corresponding to the "self check" function may be labeled as "self check" or "TEST". Users can fix various set support conditions (such as support method, a, b, c, and two radii) when the balancing machine is normal, and then put the measurement system into a "self check" state, recording the displayed readings of the "self check" state corresponding to this support condition. When the operator believes that there is a problem with the measurement system, they can restore the measurement system to the "self check" state corresponding to the original set support conditions, and then check whether the display reading of the measurement system is normal.
2. The angle of the imbalance displayed by the dynamic balancing machine is generally around 180 degrees or 0 degrees different. Firstly, confirm that the balancing machine is operating normally and the rotor still has a certain amount of residual imbalance (it is even possible to add two different phases of imbalance to the rotor on two counterweight surfaces). Under the condition of normal rotor rotation measurement, unplug the plug of sensor 1 wire and check if there is any change in the displayed value on the instrument. If there is a significant change, it indicates that the sensor wire and everything are normal. If there is no change, it indicates that there is a problem with the sensor wire or sensor. Insert the No.1 plug and then unplug the No.2 sensor wire plug. The same method can be used to determine whether the No.2 sensor wire and sensor are functioning properly. Users can find professionals to repair faulty sensor wires or sensors by comparing them to another sensor wire and sensor.
3. When the residual imbalance of the dynamic balancing machine is large, the fault is not obvious. But when the residual imbalance is small, the angle displaying the imbalance value always changes when starting the balancing machine for measurement. Sometimes the angle changes within a certain range, and sometimes the angle changes within a 360 degree range.
① To reduce interference from the same frequency, double frequency, and division frequency, the diameter of the workpiece support shaft should avoid being the same or close to the outer diameter of the support roller or its integer multiples to avoid interference. For example, if the outer diameter of the roller is 101 millimeters, it is best to avoid using shaft diameter supports within the range of 91-111, 46-55, and 32-36 millimeters.
② Strictly check the stability of the rotor assembly part. If using a process shaft, emphasis should be placed on checking the fit between the shaft and the hole.
③ Check the condition of the contact between the rotor shaft (process shaft) and the roller. If the shaft diameter is rough, the blade pattern is obvious, or the surface of the roller is damaged, it can cause instability during small signals.
④ Check the condition of the contact between the roller and the rotor shaft (process shaft). If the continuous and smooth outer surface on the roller contact surface has been damaged, it can also cause instability during small signals. When there are obvious scars on the contact surface of the roller, the display of balance is very unstable.
⑤ Clean the contact surface between the roller and the rotor shaft (process shaft) while parking, and add an appropriate amount of lubricating oil.
⑥ Carefully calculate if your balance accuracy requirements are too high.
4. When the residual imbalance of the dynamic balancing machine is large, the fault is not obvious. But when the residual imbalance is small, the angle displayed for the imbalance value always changes by approximately 180 degrees when the measurement is restarted after each balancing.
① The balance amount provided is too high.
② Strictly check the stability of the rotor assembly part. If using a process shaft, it is important to strictly check the clearance, ovality, and taper errors between the mating shaft and the hole, especially the ovality and taper errors.
2、 Four point fault diagnosis
After the above methods of inspection and maintenance are completed, if the fault still exists, the dynamic balancing machine can be inspected using the four point inspection method introduced below. In general, users can use a physical rotor according to this. If necessary, users can record the following process and all data, and then provide them to the manufacturer of the balancing machine. The manufacturer can determine more than 90% of faults based on this record.
1. Firstly, balance the rotor to the highest possible accuracy, and then prepare a detachable counterweight block that is 30-50 times greater than the residual unbalance of the rotor (the following process is as follows: use a counterweight block weighing 100 grams, and the residual unbalance of the rotor should be less than 2-3 grams). The connection and loading form between the rotor and the balancing machine remain unchanged, and proceed directly to the following test process.
2. Check whether the various settings of the dynamic balancing machine are normal.
3. Add a known weight counterweight that can be disassembled at 45 degrees around the designated counterweight circumference on either side of the rotor (assuming a counterweight weight of 100 grams below). Start the dynamic balancing machine, and the indicated values on the corresponding surface of the balancing machine should be between 40-50 degrees and 90-110 grams (according to a weight removal rate of 90%).
4. After stopping the machine, remove the counterweight and install it at a 135 degree angle around the same circumference of the rotor. Start the balancing machine, and the indicated values on the corresponding surface of the balancing machine should be between 130-140 degrees and 90-110 grams (based on a weight removal rate of 90%).
5. After stopping the machine, remove the counterweight and install it at a 225 degree angle around the same circumference of the rotor. Start the balancing machine, and the indicated values on the corresponding surface of the balancing machine should be between 220-230 degrees and 90-110 grams (based on a weight removal rate of 90%).
6. After stopping the machine, remove the counterweight and install it at a 315 degree angle around the same circumference of the rotor. Start the balancing machine, and the indicated values on the corresponding surface of the balancing machine should be between 310-320 degrees and 90-110 grams (based on a weight removal rate of 90%).
7. In the same process, install this counterweight block at four angles around the designated counterweight circumference on the other side of the rotor for inspection.
8. If the dynamic balancing machine can meet the above requirements, it is considered that there is no fault with the balancing machine.
9. If the dynamic balancing machine can approximately meet the above requirements, it is considered that there is a slight inaccurate calibration problem with the balancing machine. This issue generally leads to a decrease in operational efficiency without causing major operational errors.
If there is a slight issue of inaccurate calibration in the dynamic balancing machine, users can eliminate it according to the supporting manual of the balancing machine, or notify the manufacturer to handle it.
10. If the dynamic balancing machine does not meet the above requirements and the error is very large, the user should notify the manufacturer for handling.
11. In special circumstances, when users have doubts about the accuracy or quality of the balancing machine, they can also perform four-point fault diagnosis on the balancing machine.
Sometimes users may find that the rotor has already achieved balance accuracy on the balancing machine. Through the above methods, it is believed that the balancing machine is also functioning normally. However, during the actual installation and operation of the rotor, there is still a certain degree of vibration. At this point, it is necessary to carefully analyze other technological reasons.
Balancing machine manufacturer
3、 Carefully analyze the cause of vibration and correctly determine the true balance accuracy
There are many reasons for mechanical vibration, among which the vibration caused by the balance problem of rotating components is the most direct. But this does not mean that after the rotor is balanced on the balancing machine, all vibration problems can be solved.
The imbalance problem of the rotor is caused by the deviation of the center of gravity from the geometric centerline of the rotor's rotation. The centrifugal force generated by the rotation of the rotor rotates with the rotor, thereby stimulating vibration of the rotor and its installation foundation (such as bearing seat, frame, chassis, vehicle body, etc.).
The following will discuss some process issues related to balancing machines.
1. Process issues with the dynamic balancing machine itself
When balancing with high precision, the influence of related connectors such as universal couplings and keys should be considered. The balancing process of small rotors requires the addition of auxiliary masses such as cursors, and also needs to consider their impact on the final balancing accuracy. When the imbalance caused by these related connections is close to or even greater than the rotor balance accuracy required by the user, the imbalance displayed by the balancing machine is unreliable. For balancing machines driven by universal couplings, the balance accuracy of the universal coupling should also be regularly checked.
When using a process shaft for balance, the circular runout of the process shaft cannot exceed the rotor balance accuracy index e (eccentricity), otherwise it must be flipped 1800 for high-precision balance. Alternatively, scrap the process shaft.
In addition, the structure of the process shaft and the actual installation shaft of the rotor should be made as consistent or similar as possible to ensure that its mass distribution is consistent with the actual installation state.
2. Process issues with the rotor
Users of dynamic balancing machines should try to balance the rotor in its true installation state and ensure its rigidity.
When using a process shaft for balancing, there is an error between the process shaft and the actual installation shaft of the rotor, such as the different installation methods, keyway structures, and the respective jumps of the process shaft and the actual shaft on the process shaft. These factors can all cause changes in the imbalance amount.
When using a process shaft for balancing, it is necessary to ensure the dimensional accuracy and positional tolerance accuracy of the rotor installation hole, such as large fit clearance, elliptical or tapered hole errors, low roughness, etc., which are absolutely not allowed.
In addition, the rigidity of the rotor must be ensured. If there are sliding splines, movable blocks, swinging knife blocks, and other similar structures inside the rotor, such a rotor will never achieve the ideal balance accuracy.
3. Process issues during the actual installation of the rotor
The rotor has already achieved the required balance accuracy on the balancing machine. If some factors are not carefully considered during the actual installation and operation of the rotor, it will still cause changes in balance accuracy and even cause a certain degree of vibration.
The first factor is the actual installation shaft runout, which is very important. Because of the imbalance problem of the rotor, it is due to the deviation of the center of gravity from the geometric centerline of the rotor's rotation. The centrifugal force generated by the rotation of the rotor rotates with the rotor, thereby stimulating vibration of the rotor and its installation foundation. The installation of a balanced rotor on an eccentric actual installation shaft will naturally cause vibration of the rotor and machine.
In addition, other components that are coaxial with the rotor can also cause vibration of the rotor and machine, such as pulleys, couplings, motor rotors, etc. Their balance accuracy will also participate in the vibration of the machine together with the rotor.
Balancing Machine Company
4. Other issues
Our company's technical personnel found during after-sales service that some balance machine users did not pay attention to the early manufacturing quality of their products during the production process, and relied entirely on the dynamic balance process for the rotor's operational performance. This is very serious.
For example, in product design, the processability of the dynamic balance process is not considered;
The basic components of the product (such as brackets) are cut corners and even have serious defects;
Excessive end face runout of the fan rotor or other welded structure rotors;
The uneven mass distribution of the casting rotor has a large error;
The installation hole accuracy and roughness of the rotor are too low;
There are serious non rigid factors in the internal structure of the rotor (such as missed welding, loose rivets, etc.);
The roughness and accuracy of the process shaft are too low;
The actual installation accuracy and roughness of the rotor shaft are too low, etc,
All these factors can lead to a decrease in balance accuracy or even balance failure.
In addition, the dynamic balancing machine belongs to the instrument testing machine product category. Rough operations on the balancing machine (such as welding, sanding, etc.) can also directly affect the performance and lifespan of the balancing machine, leading to balancing failure. Please be careful.
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