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The reduction of the thermal errors of a CNC machining
Center isthe major work in this research. However, the purpose
of producingthe accuracy products and increase the machine value
are conducted at last. The evidence shows 40 to 70% of
total error are caused by machine''''s thermal drift. It is
important to develop a method to fill the thermal drift, which
associated with a changing temperature distribution within the
structural loop due to internal and external sources. The
statistical regression analysis is used to establish the thermal
drift model. With the feedback control algorithms, the
mathematical model can be used as a compensation matter on-line
to improve the thermal drift problem. In this research, an
IC type with intelligence thermal sensor, AD590, is used.
Thermal sensors with the ADVANTECH 812 A/D converter and the
personal computer constructed as a data acquisition system. The
displacements caused by the thermal drift are measured by using
LTO2S displacement gauge, which is a product of RENISHAW for
lathe. The mathematical models, which are function of
temperature varying and thermal displacement, are established
based on the multi-variable regression and nonlinear regression
statistical methods. The advancing compensation methods that
include hardware and software methods are conducted in this
research. With the experiments, the results showed the research
design with software compensation method can control the thermal
drifts within 5mm.
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