TABLE OF CONTENTS A programmed tool motion that creates a pattern, contour or a pocket in orthogonal orientation can be rotated about a defined point and by specified angle. With this control feature, there are many opportunities to make CNC programming process easier, flexible and more efficient. This very powerful programming feature is usually a special control option, and is called the Coordinate System Rotation, or just Coordinate Rotation.
One of the most important applications of coordinate rotation is a program that is defined mainly vertically or horizontally (orthographic orientation) but machined at an angle specified by the drawing. Orthographic mode defines a tool motion as parallel to machine axes. To program orthographic mode is much simpler than calculating tool positions for many contour change points in true angular orientation. Compare the two rectangles shown in Figure 42-1.
The above figure (a) shows an orthogonal orientation of a rectangle, the figure below (b) shows the same rectangle, rotated by 10 in the counterclockwise direction. Manually, it is much easier to program the tool path for figure (a) and let the control system change it to a tool path represented in figure (b). Coordinate rotation feature is a special option and must be a part of the control system.
Mathematically, coordinate rotation is a feature that re-quires only three items to define a rotated part - the center of rotation, the angle of rotation, and the tool path
