Turn grinding is cylindrical grinding with control of the grinding wheel posture. The advantages of turn grinding in comparison with cylindrical traverse grinding are reduction of the grain depth of cut and approach angle. Therefore, the grinding force can be reduced and the surface roughness can be improved because the chip shape becomes thinner. However, when the wheel-workpiece speed ratio is large, the grain depth of cut and the approach angle are too small. Therefore, it is difficult to determine the grinding conditions. This paper investigates the grinding characteristics of turn grinding. The influence of the wheel-workpiece speed ratio on the grinding force and surface roughness were evaluated. The results indicated that the surface roughness tends to improve when the wheel-workpiece speed ratio is decreased with constant wheel peripheral speed, or when both the wheel peripheral speed and the wheel-workpiece speed ratio are increased.

Thermal deformation of machine tools is one of the main causes of deterioration of machining accuracy. Accordingly, controlling temperature of the spindle and other components of the machine tools is significantly important to achieve desired machining accuracy. In general, forced fluid cooling is used for removing generated heat in machine tools. It is desired to change the cooling conditions for the temperature change of the target component, which is dependent on various machining conditions. However, conventional cooling methods do not have sufficient temperature control performance. Here, we propose a new method of fluid temperature control that achieves precise temperature control with better responsiveness. The control performance of the developed temperature control system was evaluated experimentally.