Abstract: To inspect a positioning machine by a laser tracking interferometer that tracks a retroreflector using a laser beam, the positioning accuracy of the positioning machine is evaluated by comparing a distance ?dij,C with a distance ?dij,L measured by the laser tracking interferometer, the distance ?dij,C being acquired by orthogonal projection of the position vectors of measurement points pi and pj measured by the positioning machine to the straight line gk passing through the rotation center M of the laser tracking interferometer.

Abstract: To inspect a positioning machine by a laser tracking interferometer that tracks a retroreflector using a laser beam, the positioning accuracy of the positioning machine is evaluated by comparing a distance ?dij,C with a distance ?dij,L measured by the laser tracking interferometer, the distance ?dij,C being acquired by orthogonal projection of the position vectors of measurement points pi and pj measured by the positioning machine to the straight line gk passing through the rotation center M of the laser tracking interferometer.

Abstract: A laser tracking interferometer directs a laser beam to a retroreflector serving as an object to be measured to sense a displacement of the retroreflector using interference with a laser beam back reflected from the retroreflector. The laser tracking interferometer includes: a reference sphere; a carriage that rotates about a center of the reference sphere; a laser interferometer; a displacement gage for providing a displacement signal corresponding to a relative displacement between the reference sphere and the displacement gage; a data processing apparatus for computing a displacement of the retroreflector; a position sensitive detector for providing a position signal corresponding to deviation of a laser beam; and a controller for controlling rotation of the carriage based on the position signal so that the amount of deviation becomes zero.

Abstract: A laser tracking interferometer; a carriage rotatable about a center of the reference sphere; a laser interferometer that provides a retroreflector displacement signal, and a displacement gage that provides a displacement signal. A data processing apparatus computes displacement of the retroreflector with respect to the reference sphere. A position sensitive detector provides a position signal corresponding to the amount of deviation of a laser beam when the laser beam is reflected off the retroreflector back into the laser interferometer and deviated in a direction orthogonal to its optical axis. A controller controls rotation of the carriage based on the position signal from the position detector so that the amount of deviation becomes zero.

Abstract: An electric discharge machining electrode adapted to improve the quality of a finished surface of an article by increasing a machining speed by improving the electric discharge generation rate &eegr; even in a fine machining process; and by rendering it possible to maintain constant the electric discharge generation rate &eegr; even when a time width and a voltage of the electric discharge pulses are reduced. In an electrode used in the electric discharge machining process carried out by generating electric discharge pulses between the electrode and an article, a radioactive metal is contained in the portion of the electrode in which the electric discharge pulses occur, or in the portion thereof which is in the vicinity of the portion in which the electric discharge pulses occur.

Abstract: An electric discharge machining electrode adapted to improve the quality of a finished surface of an article by increasing a machining speed by improving the electric discharge generation rate &eegr; even in a fine machining process; and by rendering it possible to maintain constant the electric discharge generation rate &eegr; even when a time width and a voltage of the electric discharge pulses are reduced. In an electrode used in the electric discharge machining process carried out by generating electric discharge pulses between the electrode and an article, a radioactive metal is contained in the portion of the electrode in which the electric discharge pulses occur, or in the portion thereof which is in the vicinity of the portion in which the electric discharge pulses occur.