Technical Information

Technical Information
Technical Information
Balancing
Balancing (continued)
permissible specific unbalance (gmm/kg)
20
15
10
5
0
5000 10000 15000 20000 25000 30000
surface finish (Ra) vs. feed rate
From the approach described in ISO 1940-1, the requirements for maximum
residual unbalance become very strict as speed increases. For example, a G 2.5
balancing grade can become unpractical at 25,000 RPM for a tool with a mass
of 1 kg. The chart shows that the maximum residual unbalance would be 1 gmm,
which could be very time consuming to be achieved or even beyond the accuracy
of the balancing machine.
Comparing the cutting forces can provide a reference for the balancing
requirements. Generally, finishing operations generate lower cutting forces and
require a better balance quality. Though rotating components should always be
balanced, in most cases it is sufficient to keep the unbalance forces to 5–10%
of the cutting forces.
M76 www.kennametal.com
G 1
G 2.5
G 6.3
(continued)