An Analysis of Methods used in Minimising Thermal Deformations of Machine Tools

Summary

This paper deals mainly with various means of improving the thermal stability of machine tools, especially machining centres. The main objects of the paper are to clarify the effectiveness of the means employed for curbing thermal deformations due to inner heat sources, and the optimum design concerning thermal deformation, if there is any. The analysis is conducted with a computer simulation using the finite element method. The following conclusions are obtained.

The use of roller guides reduces the thermal error to about 60 per cent of that of a standard machining centre which consists of a single column and sliding guides, but no cooling unit. The remedy of using a partially symmetrical double column reduces error to 50 per cent, that using a fully symmetrical double column to 30 per cent, that using a fan cooler to 55 per cent, and that using a refrigerating cooler to 9 per cent of that of the standard machine. Effectiveness would be multiplied when mutually independent means are employed simultaneously.