ISO 841 pdf download.Industrial automation systems and integration — Numerical control of machines — Coordinate system and motion nomenclature
1 Scope
This International Standard describes a machine coordinate system related to the primary motions of individual numerically controlled machines and the associated machine motions. The machine coordinate system is used to provide the coordinates of a moving tool (or a point in the working space or on the drawing) with respect to a stationary workpiece. Thus a programmer can describe the machine operations without having to know whether the tool approaches the workpiece or the workpiece approaches the tool. NOTE 1 Individual numerically controlled machines means that all axes are mounted on one base or frame and all motions are related to one standard coordinate system. NOTE 2 For the sake of simplicity the majority of the text of this International Standard is written in terms accorded to machine tools but nevertheless accorded to numerically controlled machines in general. Coordinate systems and axis motion nomenclature for industrial robots is defined in ISO 9787, Manipulating industrial robots — Coordinate systems and motion nomenclatures.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards.ISO 2806:1 994, Industrialautomation systems — Numericalcontrolofmachines — Vocabulary ISO 6983-1 :1 982, Numerical control of machines — Program format and definition of address words — Part1: Data format forpositioning, line motion andcontouring controlsystems
3 Terms and definitions
For the purposes of this International Standard, the terms and definitions given in ISO 2806 apply.
4 Machine coordinate system
4.1 Designation The machine coordinate system is a right-hand rectangular system with the three principal axes labelled X, Yand Z, with rotary axes about each of these axes labelled A, B and C, respectively (see Figure A.1 ).4.2 Origin The location of the origin of the machine coordinate system shall be defined by the manufacturer. 4.3 Z axis 4.3.1 General The Z axis is parallel to the principal spindle of the machine. For the case where the machine has no spindle, see 4.3.4 and 4.3.5. NOTE 1 On machines used for milling, grinding, boring, drilling and tapping, the spindle rotates the tool. NOTE 2 On machines such as lathes, cylindrical grinders and others which generate a surface of revolution, the spindle rotates the work piece. 4.3.2 More than one spindle Where there are several spindles, one shall be selected as the principal spindle, preferably perpendicular to the workholding surface. 4.3.3 Swivelling or gimballing spindle Where the principal spindle can be swivelled or gimballed, the Z axis shall be parallel to spindle axis when the spindle is in the zero position. The preferred zero position is with the spindle perpendicular to the work-holding surface. Where the principal spindle axis can be swivelled and if the extent of its motion allows it to lie in only one position parallel to one of the axes of the standard three-axis system, this standard axis is the Z axis. Where the extent of the swivelling motion is such that the principal spindle can lie parallel to two of the three axes of the standard three-axis system, the Z axis is the standard axis which is perpendicular to the work holding surface of the work table of the machine, ignoring such auxiliary devices as mounting brackets or angle plates. 4.3.4 No spindle For cutting and forming machines, the Z axis shall be perpendicular to the work-holding surface. For coordinate measuring machines, the Z axis should be collinear with the acceleration of gravity vector (i.e. perpendicular to the surface of the earth). 4.3.5 Direction For cutting and forming machines, the ? Z axis direction is defined from the workpiece to the tool holder. NOTE For lathes, the tail stock is considered as the tool holder. For coordinate measuring machines.