Just what does it take to be successful at balancing? Let’s start with some basics. First, you need to have an understanding of the balancing process, next nomenclature: is it unbalance, imbalance, out of balance, or what?
Use a consistent description and stick with it. Next, think about what the source of unbalance could be: is it uneven wear on parts? Voids within castings? Damage from impacting? Material buildup? Even though buildup is not usually a problem, when it begins to come off it rarely does so evenly thus creating an unbalance. In other words, unbalance is simply the uneven distribution of mass.
Simply review or collect data to ensure that the undesirable vibration is from unbalance and not some other issue such as a belt problem, misalignment, electrical issue, etc. Once you’ve determined that the vibration is indeed unbalanced you need to inspect the object to be balanced. If it is not clean, clean it. Look for damaged or broken parts. On belt-driven equipment inspect the belts as their frequency can be very close to running speed and can hinder the balance job. Make sure you have the proper tools for doing the balancing job, such as a balancing instrument capable of reading the vibration that is produced at running speed or what is commonly referred to as 1×or 1 times and capable of indicating the phase angle at 1×. This could involve utilizing an optical tachometer, laser tachometer, magnetic pickup or even a stroboscope. Some tachometers will require a piece of reflective tape on the shaft for the tachometer to read from and this might require stopping the machine if still in service.
Tip: I try to place the tape horizontally, or along the axis of the shaft, with the leading edge of the tape on the trailing edge of the keyway. This can be helpful if you ever have to return for another balancing job on the same machine. You need to determine if you will be adding or removing material in order to balance the rotating component. If removing material, how will you determine how much you’ve removed; if adding weight, you need to make sure the weight you are adding is of a material that is compatible with the service the machine is exposed to. If adding material “weights”, how will they be attached? With set screws? Bolts? Clamps? Welded on? All this should be considered. One last tip: if after two runs you’re not there or almost there yet, you might need to stop and examine your process to ensure no mistakes have been made.
Download LUDECA’s 5-Step Balancing Procedure.
Balancing, Maintenance Tips by Gary James CRL