Reduction of Thermally induce errors:-
A lot of
people have presented different methods to reduce thermal errors, put into net
shell these methods can be classified into three categories according to thesis 5946,40
Minimizing the temperature fluctuations: for example by
cooling or controlled environment condition as well as minimum heat generation
sensitivity: reducing the sensitivity of machine tool structural loop to temperature
Compensation of errors: for
example by mean of mathematical models
Reducing the temperature variations:-
Temperature variations can be minimized
by reducing the masses of machine tool structure41,thesis 594, applying cooling to a machine
tool, use of oil shower, through air.
By trying to create even temperature distribution
thermal error can be reduced of machine tool structure. Much lower the temperature
difference will be lower the thermal error present.
The temperature gradient can be
reduced by minimizing heat generated in elements of machine tool. P sekler et
al 41 of thesis illustrate thermal error can be reduced by sizing down
the masses of machine tool structure. This usually applies to construct energy
efficient machine tools but also it also helps in reducing the losses occur in machine
tool. With smaller masses less energy is required to move them result in
smaller losses and lower temperature on machine structure.
The most common approach implemented
widely in industry is to apply cooling to machine tool. Some approaches based
on try to remove the excess heat generated in machine tool elements. One of the
approaches 40 is to design special cooling element for the spindle. These cooling
tubes try to make us of Coanda-effect. Working principle of Coanda effect, fluid
passage out from nozzle creating a primary stream. Temperature control of air
in a lithography application is shown in 42. Compensation using oil shower is used in
43 and 44. Another advantage of using oil shower is that insulation from
fluctuations from in room temperature.