Imbalance correction methods: welding, drilling or weights?

Method 1: welding weights on (the most reliable)

This is the most widely used and most reliable method for the majority of industrial rotors (fans, crushers, agricultural machinery).

When to use it:

• On steel and cast-iron rotors.
• When maximum fixing reliability is required.
• Under conditions of high temperatures, shock loads or abrasive wear.

How to weld correctly:

1. Surface preparation: carefully clean the weld area down to bare metal.
2. Choosing the weight: use steel plates of the appropriate mass.
3. Welding: weld all the way round the plate. The weld must be continuous and of good quality.

Method 2: removing mass (drilling, milling)

This method is used where fitting additional weights is undesirable or impossible.

When to use it:

• On rotors where protruding parts are not permissible (high-speed rotors).
• On motor armatures, turbine rotors and spindles.
• When very precise correction is required.

Where you can drill:

• Purpose-made bosses on the rotor.
• The faces of discs (away from stress-concentration zones).
• Stiffening ribs (if the design allows).

Method 3: fitting removable weights (bolts, clamps)

This method is convenient for quick correction and where welding is not permissible.

When to use it:

• On rotors that have dedicated threaded holes for balancing bolts.
• On car wheel rims (balancing clip-on weights).
• When frequent re-balancing is needed.

Important points:

• Use high-strength fasteners (grade 8.8 and above).
• Always use washers or thread-locking compound (such as Loctite) to prevent the fastener from working loose under vibration.

Work safety

Working with correction weights demands strict adherence to safety procedures.

• All work to fit and remove weights is carried out only on equipment that is fully stopped and isolated (the LOTO procedure).
• When welding, observe all fire-prevention precautions.
• After fitting a weight, make sure it does not catch on any stationary parts of the casing.