Evaluation - Overall value measurement EasyBalancer EB 3500
10 - 6
Assessment of
vibration measurements
The assessment and limit values for machine vibrations contained
in DIN ISO 20816 are operating guideline values which relate to
the dynamic continuous load capacity of the complete machine
design. They apply to the complete machine set, at the installa-
tion site and under operating conditions. These assessment and
limit values are guideline values obtained from experience and
statistically processed; like all empirical values, their absolute val-
ues can neither be physically justified nor mathematically proven.
Differences and exceptions are therefore possible in individual
cases.
In the vibration assessment of machine tools, the dynamic con-
tinuous load capacity is normally not of interest; other criteria usu-
ally apply here. The vibration behaviour of a machine tool should
be so good that, for example, no chatter marks appear on the sur-
face of the machined workpieces during the machining process.
This criterion then leads to a substantially higher demand on
the vibration behaviour of the respective machine. Although there
are no official standards or guidelines yet, the following guideline
values can be given based on various experiences:
Example for assessment
Carry out a comparison of overall vibration / unbalance
vibration.
Precondition: Overall vibration is greater than unbalance
vibration.
The vibration level is not significantly improved by balancing.
Carry out vibration analysis.
Two examples in figures:
Overall vibration v
eff
= 8.5 mm/s
Unbalance vibration v
eff
= 7.2 mm/s
Balancing makes sense.
Overall vibration v
eff
= 7.7 mm/s
Unbalance vibration v
eff
= 1.3 mm/s
Balancing not efficient.
Grinding machines < 0.4 mm/s Veff
Automatic lathes < 0.8 mm/s Veff
Precision drills < 0.8 mm/s Veff
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