Page 34 - AMTDC Annual Report 2019-20flipbook
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Development of Thermal Compensation Strategy
Scope/ Objective:
1. To develop compensation algorithm and electronics specific
to a product for thermal compensation at the tool centre point. Providing Corrections
2. To map the thermal behaviour of the machine with respect to at the Tool Point
the temperature at the various critical zones of the machine and
also, with the variations in ambient temperature. The thermal behaviour of the
3. To analyse the captured data to map the behaviour of the machine has a large impact on the
machine under various conditions. structural deformation of the
4. To develop a framework for performing thermal compensation machine, which in turn affects the
for machine tools, especially for CNC lathes. accuracy of the machined parts. By
predicting the behaviour of the
Project Overview: structure with respect to the thermal
variations, it is possible to provide
The project started with the testing and evaluation of the corrections at the tool point so that
current accuracy level of the Vantage 800 lathe machine. the accuracy achieved on the
Thermal error component was found to be varying from 30µm to component can be improved. The
50µm whereas the non-thermal component from 4µm to 5µm present-day control systems used on
for machining a component of diameter 50mm and length
200mm. For the characterisation of thermal behaviour of a CNC the Lathe is capable of automating
lathe machine, suitable temperature and displacement sensors the corrections with the data
were identified and installed. Diameter deviations were generated from specific algorithm
measured during the cutting trials with and without coolant. unique to the product. The challenge
Measurements of TCP drift and X- axis growth were taken to lies in completely understanding the
capture the effect of various operating conditions such as spindle machine behaviour on experimental
rotation, axis movement, etc., with and without coolant, using basis and mapping the same thro
eddy current sensors. ANSYS Thermal Transient software was simulation processes. Developing the
used to simulate the various conditions identified from the capability to replicate the process on
experiments. Various mathematical models were developed such various models of machines is also a
as multi-variable linear regression, support vector machines, challenge.
ensemble models to predict the variation of tool point based on
temperature.
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AMTDC Annual Report | 2019-20
