Temperature-compensated laser measuring method and apparatus

摘要

A temperature-compensated laser measuring method and apparatus for determining the dimensions of long parts is disclosed. Parts to be measured are positioned along a y-axis fence (19) against an x-axis fence (21). A gantry (15) is moved along a precision support rail (17) to the desired longitudinal (x-axis) position. Then a probe (23) is moved inwardly or outwardly to a desired y-axis position and lowered to a desired z-axis position. A Doppler laser measuring system that includes a Doppler laser head (25) and retroreflector (27) measures x-axis length. Y-axis and z-axis encoders (29, 31) determine y-axis and z-axis probe position with respect to the y-axis fence and the top (39) of the table (13). A temperature compensation unit (103) receives the laser measurement information and modifies the x-axis length measurement based on part temperature and the coefficient of expansion of the part. A display system (33) receives all of the position and measurement information and displays length, width, and height dimensions.