Study on Self Compulsory Cooling for Reducing Thermal Deformation of Machine Tool. Evaluation of Property on Thermal Self Control.

Abstract

As higher precision machining is required, reducing thermal deformation of a machine tool becomes more important. And in the 21 st century, as it is also important to produce a product with care for protecting the earth, a producer must be careful on conservation of energy, Therefore, in previous report, a self compulsory cooling for reducing thermal deformation was proposed. This method is the compulsory cooling using water evaporation ; a cloth is bonded on a machine tool surface, water is supplied in the cloth by capillarity and wind is also supplied on the cloth by a fan which is bonded on a spindle of a machine tool, then heat of the machine tool surface is removed by water evaporation, and thermal deformation of the machine tool is finally reduced. The countermeasure were very cheap and effective in order to reduce thermal deformation. Furthermore, property on self control of the proposed countermeasure was evaluated. Property on self control is explained in the following ; it is important to be evaporated a large quantity of water for increasing cooling capacity of this method, on one hand, heavy load of a machine tool means that strength of heat source on spindle bearings becomes large and spindle speed with a fan becomes faster, and at that time, as large heat source and strong wind are supplied on the cloth with water, water evaporation increases very much, then cooling capacity also increases. In the experiment, a lathe with cloth on the front surface of head stock and with a fan on spindle was used for evaluating property of self control. It is concluded from the results that the proposed property of self control are effective toward the various working conditions.