Setting up a manufacturing facility takes a great deal of planning, design, build and testing, not to mention investment. From engineering and prototyping to fabrication, finishing, assembly and inspection, there’s a great deal to consider.
So once operational, every aspect needs to run smoothly to achieve a return on investment with long term reliability, efficiency and quality control all key deliverables in achieving this.
Dynamic and static balancing of manufacturing components and plant are vital considerations for any manufacturing facility, as without building them into your quality control process you are asking for production downtime, shorter asset life, poor quality and ultimately devastating failure.
Simply put, balancing is a method through which rotating parts of manufacturing plant or components are balanced, ultimately to avoid vibration, and this can be achieved by moving the centre of gravity to the centre of rotation.
Unbalance is often realised as the result of casting faults, rotor design features, production processes, dimension tolerances, keyways and the weight of symmetrical features.
And there are generally two forms of unbalance: static and dynamic. The total unbalance is called static if it is a single vector parallel to the axis of rotation and contains the centre of mass, whereas dynamic unbalance is compensated on two different planes. Both occur in numerous applications across many different operations.
There are two ways to correct unbalance.
Adding material:
Examples include:
- Weights to car wheels
- Screws to tool holders
- Epoxy putty to electric motors
- Clips to fans
- Pins to plastic mouldings
- Moveable masses to grinding wheels and tool holders
- Welding weights to impellers
Removing material:
Examples include:
- Drilling flywheels and crankshafts
- Milling brake discs and clutches
- Grinding cutting tools
- Turning impellers
Balancing delivers many benefits including higher operation speeds, increased production, lower production costs, increased equipment and plant life, improved manufacturing uptime for optimum production and lower maintenance costs of repair, replacement and parts.
So by making balancing an integral part of the quality control process, the long-term health and viability of the manufacturing operation is being secured.
Glossary of balancing terms
Unbalance
Uneven mass distribution around the axis of rotation.
Total unbalance
Set of local unbalance vectors.
Centre of mass
The point to which the mass moment if zero.
Eccentricity
The distance between the centre of mass and the axis of rotation.
Axis of inertia
The line to which the mass static moment is zero.
Static unbalance
The total unbalance is called static if it is equivalent to only one unbalance vector placed in a plane passing through the centre of mass.
Couple unbalance
The total unbalance is called couple unbalance if it is equivalent to two unbalance vectors, placed on two different planes, having the same amount but in different directions.
Dynamic unbalance
The total unbalance of a rotor is always equivalent to a dynamic unbalance, that is two unbalance vectors placed on two arbitrarily different planes.
