Abstract: A coordinate measuring machine includes a support structure, an articulated arm having a first end pivotally connected to the support structure and a second end that is movable in a horizontal plane. A Z-ram assembly is mounted to the second end of the articulated arm. The Z-ram assembly includes a Z-ram housing and a probe that is vertically movable with respect to the Z-ram housing. The probe is movable within a measurement volume defined by the articulated arm and the Z-ram assembly. The coordinate measuring machine further includes a measuring assembly for determining coordinates of the probe in the measurement volume. The articulated arm preferably includes first and second arm assemblies that have a parallelogram configuration to prevent substantial rotation of the Z-ram assembly as the articulated arm is moved in the horizontal plane. The angles of the articulated arm are preferably measured using a sensor which includes a pattern of parallel, straight grating lines.

Abstract: The invention comprises a contacting block step gage in which the individual blocks are fastened together under extremely high compressive forces by a tension tube and four individually adjustable screws. The screws can be individually torqued to compensate for bending of the gage.

Abstract: The invention comprises a contacting block step gage in which the individual blocks are fastened together under extremely high compressive forces and any bending of the step gage is compensated for and in which the measuring surface is on the neutral axis of the gage and accessible via probe clearance channels in the blocks.

Abstract: Methods for determining nonrigid error parameters that result from deflection or deformation of machine elements and correcting scale readings in a coordinate measuring machine. The nonrigid error parameters are a function of probe position along two directions. In a bridge type coordinate measuring machine, the y-direction error parameters are a function of probe position in both x and y directions and thus exhibit nonrigid behavior. Nonrigid error parameters are measured by making error measurements at a plurality of corresponding points along two parallel, spaced-apart measurement lines. The error measurements are substituted into simultaneous equations for the error parameters, and the equations are solved for the coefficients. The coefficients are used to determine the axial errors at any point in the measuring volume. The axial errors are subtracted from the scale readings.

Abstract: A calibration system for measuring the parametric errors in a coordinate measuring machine having a first element and a table which are movable in three dimensions relative to each other. The apparatus comprises a reflector assembly attachable to the first element, a laser measuring assembly attachable to the table for directing a plurality of laser beams at the reflector assembly and for sensing laser beams reflected from the reflector assembly and generating displacement, straightness, pitch, yaw and roll error signals, and means for mounting the laser measuring assembly to the table in three different orientations and for mounting the reflector assembly to the first element in three different orientations. In each of the orientations, the reflector assembly and the laser measuring assembly are aligned for measurement of parametric errors at a plurality of selected positions along the direction of the laser beam. The parametric errors along each direction of movement are stored in a computer.

Abstract: A ball bar gauge for evaluating the performance of coordinate measuring machines is disclosed. The gauge consists of a rigid bar having a magnetic chuck at each end. Each magnetic chuck consists of a permanent magnet and six magnetic pole pieces surrounded by a non-magnetic housing. The bar is used with two precision tooling balls which are placed in the chucks at each end of the rod. In each chuck three of the pole pieces are slightly longer than the other three pole pieces to provide a stable three-point contact seat for the associated ball.