According to JB3051-82, the positive direction of movement of a part of a machine tool is the direction to increase the distance between the workpiece and the tool.
(1) Z coordinate movement
The Z coordinate motion is determined by the principal axis that transmits the cutting force, and the coordinate axis parallel to the spindle axis is the Z coordinate. Spindles such as lathes, grinders, etc. drive the rotation of the workpiece; for spindles such as milling machines, drill presses, boring machines, etc., with tool rotation, the coordinate axis parallel to the spindle is the Z coordinate. If the machine does not have a spindle (such as a planer), the Z axis is perpendicular to the workpiece loading surface.
The positive direction of the Z coordinate increases the distance between the workpiece and the tool. For example, in drilling boring, the direction of drilling and boring into the workpiece is the negative direction of the Z coordinate, and the exit is the positive direction.
(2) X coordinate movement
The X coordinate is horizontal and it is parallel to the mounting surface of the workpiece. This is the main coordinate movement in the tool or workpiece positioning plane. For machine tools that rotate workpieces (such as lathes, grinders, etc.), the direction of the X coordinate is in the radial direction of the workpiece. The direction of the tool away from the center of rotation of the workpiece is the X-axis positive direction. For the tool rotating machine (such as milling machine, boring machine, drilling machine, etc.), if the Z axis is vertical, the positive direction of the X motion will point to the right when viewed from the main axial column of the tool, if the Z axis (main axis) is horizontal, When looking from the direction of the main axis of the workpiece, the positive direction of the X movement points to the right.
(3) Y coordinate movement
The Y axis is perpendicular to the X and Z axes. The positive direction of the Y motion is determined from the right-handed right-angled Deckar coordinate system based on the positive direction of the X and Z coordinates.
(4) Rotary motions A, B, and C
A, B, and C correspondingly represent rotational motions whose axes are parallel to the X, R, and Z coordinates. The positive directions of A, B and C correspond accordingly to the forward direction of the right-hand thread in the positive direction of the X, Y and Z coordinates.
(5) Additional coordinates
If there are coordinates parallel to them other than the X, Y, Z major coordinates, they can be specified as U, Y, and W, respectively. If there is a third group of movements, specify P, Q, and R, respectively.
(6) For the opposite direction when the workpiece is moving
For a machine tool whose workpiece motion is not a tool motion, the aforementioned provisions for tool motion must be reversed. Use a letter with a '', such as +X, to indicate the workpiece's positive movement command with respect to the tool. Letters without “', such as +X, indicate the positive motion of the tool relative to the workpiece. The movement direction of the two represents the opposite. For programmers and craftsmen only consider the direction of movement without ''.
(7) The direction of spindle rotation refers to JB3208-83 "Preparation of G and Auxiliary Function Codes in Punching Tape Program Formats of CNC Machines".
