important part of an investigation of such problems is the measurement of
the load-v-deflection characteristics of the machine so that problems of
poor stiffness can be readily identified. UNIVIB, however, goes a step further
and makes use of its modal analysis software to produce exaggerated, slow-motion
animations of the way in which the structure distorts under load. This enables
rapid identification of the exact source of the unwanted flexibility.
stiffness of manufacturing machines, especially metal cutting machine tools
such as machining centres, lathes and grinding machines, is important because
it governs the magnitude of the displacement, or push-off, of the tool as
it deflects under the influence of the cutting forces, and this of course
affects the accuracy of the finished component. Many's the time that, in
order to achieve the required component accuracy, a second pass comprising
a lighter finishing cut has to be performed and this has a knock-on effect
on cycle time. The accuracy of components produced by metal forming machines
such as presses, guillotines, nibblers etc. can be equally undermined by
lack of stiffness of the structure of the machine.
Surface finish problems such as chatter marks associated with chatter
vibration during cutting can also sometimes be attributed to a lack of
stiffness of the machine on which the operation is being carried out.