balancing machine?
balancing machine in use due to improper operation or maintenance is not done well, there will be many problems; Sometimes our technical after-sales personnel go to the customer site and find that the problems to be solved are actually not difficult, mainly because there is no one familiar with the operation of the balancing machine. Light will be basicbalancing machinethe operation is not enough, but also the operation master knows the daily maintenance of the balancing machine, the correct operation of the switch machine, and the precautions during operation.
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1. The measurement system of most dynamic balancing machines has a "self-check" function, which can detect whether the measurement system itself is normal. The operation button corresponding to the "self-test" function may be marked as "self-test" or "TEST", etc. When the balancing machine is normal, the user can fix various set supporting conditions (supporting mode and a, B, c and two radii, etc.), then make the measuring system enter the "self-check" state, and record the display reading corresponding to the "self-check" state under this supporting condition. When the operator thinks that there is a problem with the measuring system, the measuring system can be restored to the "self-check" state under the supporting conditions corresponding to the original setting, and then check whether the display reading of the measuring system is normal.
2. The angle of the unbalance displayed by the dynamic balancing machine is always about 180 degrees or 0 degrees. First of all, confirm that the balancing machine is running normally and the rotor still has a certain amount of residual unbalance (even two different phases of unbalance can be added to the rotor on the two counterweight surfaces). Under the condition of normal rotation measurement of the rotor, unplug the No. 1 sensor line plug and see if the meter shows any change in the value. If there are obvious changes, it proves that the sensor line and sensor are all normal. If there is no change, it proves that there is a problem with this sensor wire or sensor. Plug in the No. 1 plug, and then unplug the No. 2 sensor line. The same method can determine whether the No. 2 sensor line and sensor are normal. The user can find a professional to repair the faulty sensor wire or sensor against another sensor wire and sensor.
3, dynamic balancing machine in the residual imbalance is large, the fault is not obvious. However, when the residual unbalance is small, the angle showing the unbalance value is always changing when the balancing machine is started to enter the measurement. Sometimes the angle changes within a certain range, and sometimes the angle changes within a range of 360 degrees.
① In order to reduce the interference of the same frequency, frequency multiplication and frequency division, the diameter of the workpiece support shaft should be the same as or close to the outer diameter of the support roller or its integral multiple integral fraction to avoid interference. For example, if the outer diameter of the roller is 101mm, it is best to avoid using shaft diameter supports in the range of 91~111, 46~55, and 32~36mm.
② Strictly check the stability of the rotor assembly part. If the process shaft is used, the fit between the shaft and the hole should be checked.
③ Check the contact state of the rotor shaft (process shaft) and the roller. If the shaft diameter is rough, the knife pattern is obvious or the roller surface is damaged, it will cause instability when the signal is small.
④ Check the contact state of the roller and the rotor shaft (process shaft). If the continuous smooth outer surface on the roller contact surface has been destroyed, it will also lead to instability when the signal is small. When the contact surface of the roller appears more obvious damage, the balance of the display is very unstable.
Clean the contact surface between the roller and the rotor shaft (process shaft) in the parking state, and add appropriate amount of lubricating oil.
⑥ carefully calculate whether your balance accuracy requirement is too high.
4, dynamic balancing machine in the residual imbalance is large, the fault is not obvious. However, when the residual unbalance is small, the angle indicating the unbalance value always changes by substantially 180 degrees when the measurement is restarted after each balancing.
① The balance amount is too large.
② Strictly check the stability of the rotor assembly part. If the process shaft is used, the clearance, ellipticity and taper error of the matching shaft and hole should be strictly checked, especially the ellipticity and taper error.
2. four-point fault diagnosis
After testing and maintenance according to the above methods, if the fault still exists, the balancing machine can be inspected according to the four-point inspection method of the dynamic balancing machine described below. Under normal circumstances, the user can use this physical rotor. If necessary, the user can record the following process and all data, and then provide it to the manufacturer of the balancing machine, and the manufacturer can judge more than 90% of the faults according to this record.
1. First, balance the rotor to the highest accuracy that can be achieved, and then prepare a removable counterweight that is greater than 30 to 50 times the residual unbalance of the rotor (the following process is as follows: the counterweight weighs 100 grams, and the residual rotor should be less than 2 to 3 grams). Rotor and balancing machine coupling and loading form unchanged, directly into the following test process.
2. Check whether the various settings of the dynamic balancing machine are normal.
3. Add a removable counterweight with a known weight at 45 degrees of the specified counterweight circumference on any surface of the rotor (it is assumed that the counterweight weighs 100 grams below). Start the dynamic balancing machine, and the indicating value of the corresponding surface of the balancing machine should be 40-50 degrees and 90-110 grams (according to 90% weight removal rate).
4. After shutdown, remove the counterweight and install it on the same circumference of the rotor at an angle of 135 degrees. Start the balancing machine, and the indicating value of the corresponding surface of the balancing machine should be 130-140 degrees and 90-110 grams (according to 90% weight removal rate).
5. After stopping the machine, remove the weight and install it on the same circumference of the rotor at an angle of 225 degrees. Start the balancing machine, and the indicating value of the corresponding surface of the balancing machine should be 220-230 degrees and 90-110 grams (according to 90% weight removal rate).
6. After stopping the machine, remove the weight and install it at an angle of 315 degrees at the circumference of the same surface of the rotor. Start the balancing machine, and the indicating value of the corresponding surface of the balancing machine should be 310-320 degrees and 90-110 grams (according to 90% weight removal rate).
7. In the same process, install the counterweight block in turn at 4 angles at 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 the balancing machine has no fault.
9. If the dynamic balancing machine can approximately meet the above requirements, it is considered that the balancing machine has a slight calibration inaccuracy problem. This problem generally causes a decrease in operation efficiency without causing a large operation error.
If the dynamic balancing machine has a slight calibration inaccuracy problem, the user can exclude it according to the contents of the balancing machine supporting instructions, or notify the manufacturer to deal with 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 to deal with it.
11. Under special circumstances, when the user has doubts about the accuracy or quality of the balancing machine, the balancing machine can also be diagnosed by the four-point method.
sometimes users will find that the rotor has reached the balance accuracy on the balancing machine. Through the above method, it is believed that the balancing machine is also normal, but when the rotor is actually installed and operated, there is still a certain degree of vibration. At this time, it is necessary to carefully analyze other technological reasons.
3. carefully analyze the causes of vibration and correctly judge the true balance accuracy
, among which the vibration caused by the balance of rotating parts 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.
rotor is due to the center of gravity of the rotor, which deviates from the geometric center line of rotation of the rotor. When the rotor rotates, the resulting centrifugal force rotates with the rotor, thereby exciting the rotor and the installation foundation of the rotor (such as: bearing seat, machine base, chassis, body, etc.) to produce vibration.
Some of the process problems associated with balancing machines are discussed below.
1, dynamic balancing machine itself process problems
high-precision balance, the influence of universal couplings, keys and other related connections should be considered. The small rotor balancing process needs to add the cursor and other ancillary mass, but also need to consider its impact on the final balance 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 the balance machine driven by universal coupling, the balance accuracy of universal coupling should also be checked regularly.
When the process axis is used for balance, the circular runout of the process axis cannot be greater than the rotor balance accuracy index e (eccentricity), otherwise it must be turned over 1800 high-precision balance. Or discard the process shaft.
In addition, the structure of the process shaft and the structure of 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, the rotor process problems
Dynamic balancing machine users should try to use the real installation state of the rotor to balance, and to ensure its rigidity.
is balanced by the process shaft, there are errors between the process shaft and the actual installation shaft of the rotor, such as the different installation methods of the rotor on the process shaft and the actual shaft, the keyway structure, and the respective runout of the process shaft and the actual shaft. These factors will cause changes in the amount of unbalance.
is balanced by the process shaft, the dimensional accuracy and form and position tolerance accuracy of the rotor mounting hole must be ensured, such as large fit clearance, hole ellipse or taper error, low roughness and so on, which are absolutely not allowed.
In addition, the rigidity of the rotor must be ensured. If there are sliding splines, movable blocks, swinging cutters and other similar structures inside the rotor, such a rotor will never reach the ideal balance accuracy.
3, the actual installation of the rotor process problems
the rotor has reached the required balance accuracy on the balancing machine, when the rotor is actually installed and operated, if some factors are not carefully considered during the actual installation process, it will still cause changes in the balance accuracy and even cause a certain degree of vibration.
first is the beating of the actual installation shaft, which is very important. Because the imbalance of the rotor is due to the center of gravity of the rotor, it deviates from the geometric center line of rotation of the rotor. When the rotor rotates, the centrifugal force generated by this rotates with the rotor, thereby exciting the rotor and the installation foundation of the rotor to generate vibration. The well-balanced rotor is installed on the actual installation shaft with eccentricity, which of course will cause vibration of the rotor and the machine.
In addition, other parts coaxial with the rotor will also cause the vibration of the rotor and the machine, such as pulleys, couplings, motor rotors, etc., and their balance accuracy will also participate in the vibration of the machine together with the rotor.
4. Other issues
our company's technical personnel in the after-sales service found that there are individual balancing machine users in the production process of its products, do not pay attention to grasp the quality of its products in the early stage of manufacturing, and the operation performance of its rotor is completely dependent on the dynamic balancing process, which is very not serious.
example: product design does not consider the process of dynamic balancing process;
products (such as stents, etc.) cut corners and even have serious defects;
The end surface runout of the rotor of the fan or the rotor of other welded structures is too large;
the mass distribution of the cast rotor is too large;
rotor are too low;
There are serious non-rigid factors in the internal structure of the rotor (such as welding leakage, rivet loosening, etc.);
process axis are too low;
the actual installation of the rotor shaft accuracy and roughness is too low, and so on,
all these factors will lead to the reduction of balance accuracy and even balance failure.
In addition, the dynamic balancing machine is an instrument testing machine product. The brutal operation of the balancing machine (such as welding, sanding, etc. on the balancing machine) will also directly affect the performance and life of the balancing machine, resulting in the failure of the balance, so pay attention to it.
