Machine tools and methods of operation thereof

Abstract

A machine tool is provided which comprises a machine base (10); a first support (200) provided on a first rotational machine axis, the first rotational axis being mounted on the base in a fixed position relative to the base; a second support (202) provided on a second rotational machine axis, the second rotational axis being mounted on the base in a fixed position relative to the base, wherein the axis of rotation of the second rotational axis is parallel to and spaced laterally from the axis of rotation of the first rotational axis. A mount is carried by a support arm on the second support, with the support arm being moveable relative to the second support about a rotary axis (210, 232, 252). A control arrangement is operable to control the orientation of the first support relative to the axis of rotation of the first rotational axis, and the orientation of the mount relative to the axis of rotation of the second rotational axis and its rotational position about the rotary axis, so as to govern the position and orientation of the first support and the mount relative to each other. Combination of motion about three rotational axes in this way facilitates versatile and accurate control of the relative orientations of the first support and the mount on the second support. The machine base may include a central support (320) located between the machine axes (322, 324), with the machine axes mounted onto opposite sides of the support.

Description

technical field [0001] The present invention relates to machining tools, and in particular, the present invention relates to reducing alignment errors in such tools. Background technique [0002] Many applications for machining tools require that two points in space move relative to each other in controlled position and angle over a swept area or extent of space. It is desirable to optimize this control by minimizing the number of machine axes involved. It is also desirable to maintain a very tight rigid loop between two points, and ideally keep the stiffness value in the loop constant when adjusting the position and angle of the points. This improves the level of precision and repeatability of movements. [0003] Existing machining tools typically use long linear guide rails in order to allow contact between the cutting tool (eg, grinding wheel) and the workpiece at any position along the length of the workpiece. The shorter linear guide rails may be carried by the longe...