Abstract
Friction (hydrodynamic) guideways have been used as a feed drive system of traditional NC machine tools, such as machining centers. It is known that the machine that has this type of guideways is good for heavy cutting. On the other hand, it has more friction, and so the driving system has larger lost motion, in consequence, positioning accuracy can be worse without linear encoder feedback. Recent friction gudeway design has been dealing with the friction decrease. This paper describes the comparison of motion accuracy (mainly the amount of lost motion) of the machines built in these ten years by using circular test measurement.
