ASME B89.3.4-2010 pdf download.Axes of Rotation: Methods for Specifying and Testing.
2.1.10 Axis Shift axis shift: a change in position of the axis of rotation caused by a change in operating conditions. NOTES: (1) Causes ofaxis shiftinclude thermal drift, load changes, preload changes, and speed changes. (2) An axis shift that occurs during an error motion measurement will affect the error motion values. (3) Error motion specifications assume constant conditions unless specified otherwise. 2.1.11 Displacement Indicator displacement indicator: a device that measures changes in distance between two objects. NOTE: Examples include capacitive gages, linear variable differ- ential transformers (LVDTs), eddy current probes, laser interferom- eters, and dial indicators. 2.1.12 Structural Loop structuralloop: theassemblyofcomponents thatmaintain the relative position between two specified objects. NOTE: A typical pair of specified objects is the cutting tool and the workpiece; the structural loop would include the workpiece, chuck, spindle rotor, bearings, stator, headstock, the machine slideways and frame, the tool holder, and the cutting tool. (In this Standard, a displacement indicator qualifies as a tool.) 2.1.13 Structural Error Motion structural error motion: error motion measured from the spindle stator to the tool, from the rotor to an object mounted to the rotor, or from any two specified objects outside the stator-to-rotor structural loop. 2.1.14 Sensitive Direction sensitive direction: the direction normal to the surface of a perfect workpiece through the instantaneous point of machining or measurement (as shown in Fig. 2). 2.1.15 Nonsensitive Direction nonsensitive direction: any direction perpendicular to the sensitive direction. 2.1.16 Fixed Sensitive Direction fixed sensitive direction: the sensitive direction is fixed when the workpiece is rotated by the spindle and the point of machining or measurement is not rotating.
2.1.18 Orientation Angle orientation angle: the angle between the circumferential position of a designated feature on the spindle stator or rotor and the point of machining or gaging. NOTES: (1) Specification of the orientation angle enables a spindle to be installed with the same orientation in which it was tested or specified. (2) The orientation angle is specified with respect to a designated feature on the stator for fixed sensitive direction or on the rotor for rotating sensitive direction. 2.1.19 Direction Angle direction angle: the angle of the sensitive direction with respect to the axis of rotation. NOTES: (1) Axial measurements have a direction angle of 0 deg and radial measurements have a direction angle of 90 deg. (2) The directionangle mustbe specified ifthe measurementdirec- tion is at some angle other than in the radial or axial direction (see Fig. 2). 2.1.20 Runout runout: the total displacement measured by an indicator sensing against a moving surface or moved with respect to a fixed surface. NOTES: (1) The term“TIR” (totalindicatorreading) is equivalentto runout. (2) Surfaces have runout; axes of rotation have error motion. (3) Runout includes errors due to centering and workpiece form errors and hence is not equivalent to error motion. 2.1.21 Stationary-Point Runout stationary-point runout: the total displacement measured by sensing against a point on a surface that is not intended to move laterally with respect to the indicator. NOTES: (1) This term applies when two or more axes of a machine are simultaneously moved to keep a point stationary with respect to the indicator. (2) Stationary-point runout also describes a variety of chase-the- point measurements such as rim-and-face measurements for alignment of two axes of rotation. 2.1.22 Master Axis master axis: the axis of rotation of a precision spindle used to measure error motions of another spindle.
2.1.24 Squareness squareness: a plane surface is square to an axis of rotation if coincident polar profile centers are obtained for an axial and a face error motion polar plot or for two face error motion polar plots at different radii. NOTE: The term “perpendicularity” is equivalent to squareness. 2.1.25 Play play: a condition of low or zero stiffness over a limited range of displacement, due to clearance between ele- ments of a structural loop. 2.1.26 Setup Hysteresis setup hysteresis: nonrepeatability ofposition between ele- ments in a test setup, normally due to loose mechanical connections or friction. 2.1.27 Pure Radial Motion pure radial motion: the concept of radial motion in the absence of tilt motion. 2.2 Error Motions 2.2.1 Error Motion error motion: changes in position, relative to the reference coordinate axes, of the surface of a perfect workpiece, as a function of rotation angle, with the workpiece cen- terline coincident with the axis of rotation. NOTES: (1) Error motions are specified as to location and direction as shown in Fig. 2, illustration (a) and do not include motions due to changes in operating conditions unless specified otherwise. (2) The concept of a perfect workpiece enables easier visualization of error motion. Also, in practice all measurements are made from solid surfaces rather than abstract lines. 2.2.2 Spindle Error Motion spindle error motion: generic term for any error motion associated with a spindle measured between the ends of a structural loop.