29-12-2010, 05:19 PM
GUIDED BY
PROF. B. Koti Veerachari
SUBMITTED BY
Rakesh Kumar
PROF. B. Koti Veerachari
SUBMITTED BY
Rakesh Kumar
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List of contents
Introduction
Types of vibration
Effects of vibration
Sources of vibration excitation
Vibration control in machine tool
Damping
Conclusion
References
Introduction
Machining and measuring operations are invariably accompanied by vibration.
To achieve higher accuracy and productivity vibration in machine tool must be controlled.
For analysis of dynamic behavior of machine tool rigidity and stability are two important characteristics.
Damping
The major part of the damping results from the interaction of joined components at slides or bolted joints.
The interaction of the structure with the foundation or highly damped vibration isolators also may produce a noticeable damping.
structural damping is significantly higher for frame components made of polymer-concrete compositions or granite.
A significant damping increase can be achieved by filling internal cavities of the frame parts with a granular material.
For cast parts it can also be achieved by leaving cores in blind holes inside the casting.
Damping can be increased by the use of dampers and dynamic vibration absorbers.
Damping can be achieved by placing auxiliary longitudinal structural members inside longitudinal cavities within a frame part.
A variation of the Lanchester damper is frequently used in boring bars to good advantage.
