Balancing: ensuring everything is working as it should be
Balancing is the procedure of trying to enhance the mass spread of a body so as to rotate in its bearings without the unbalanced centrifugal forces acting on it. When the machine is running in balance, it is working as it should be. This process minimises the vibration and reduces the levels of noise as well as extending the life of a machine.
Vibration: is all vibration a problem?
Vibration will always be an element of any machinery that rotates, and although some levels can be acceptable, the main goal of any rotating equipment is to operate with as little vibration as possible to avoid damage and ultimately extend the lifespan of the machine. Instead of trying to remove all the vibration therefore, it is essential to carry out searches for machinery balance in order to minimise the vibration to the point at which there is a reduced level of noise.
Two types of balancing
There are two basic types of balancing that can be carried out on your machinery – Static and Dynamic:
Static balancing (knife edging)
When we balance a section of machinery statically, its centre of gravity is located in the axis of its rotation. This process implies that it will remain stationary at the horizontal axis, without applying a braking force. The unbalance will be present even when the rotor is not spinning.
Low friction bearings are used to settle the component so that the heaviest part is at the bottom. We then remove material from the lower portion (heavy side). Or add on top (light side) until it rotates on a true axis. We repeat this process until the point that is heavy disappears and the rotor no longer rotates without assistance.
2. Dynamic balancing (single and multiplane)
Dynamic balancing involves the adjustment of an object’s balance by adding or removing weight. Firstly, we have to determine the components unbalance. We calculate this whilst it’s rotating at a predetermined speed. The information from this process gives insight into the amount of weight required to counterbalance areas that are either too light or too heavy.
Reducing vibration through dynamic balancing also ensures the machine is running smoothly, with reduced noise. This inevitably prevents premature system failure. A component is only in balance once the rotation does not produce any centrifugal force or couple unbalance as a result.
We can perform Dynamic balancing on components of a variety of shapes and sizes. Single plane dynamic balancing is normally carried out on relatively low speed and narrow disks, where the width is less than 30% of the diameter.
Dynamic balancing (multi plane) is primarily performed on components rotating at higher speeds, where the width is more than 30% of the diameter. We balance long and high speed rotors (including flexible rotors) using more than two correction positions.
So, which should you choose?
Balancing of your machinery, whether its static or dynamic is key to eliminating common performance problems. These problems often include vibration, noise, and heat. Eliminating these will consequently extend its lifespan, improve accuracy, and avoid premature system failure.
A key benefit of dynamic balancing that makes it the preferred technique, especially for high-performance components, is that objects can be balanced with extreme accuracy – often within fraction of grams.
On assessment, your expert team at WDB Ltd will advise you on the best form of balancing to ensure your machine is operating as efficiently as possible.