METHOD AND APPARATUS FOR INSPECTING WORKPIECES

摘要

A series of nominally identical workpieces is received from a manufacturing process and measured on a measuring apparatus. They are received at a non-ambient temperature because of heat introduced during the manufacturing process, but they are placed on the measuring apparatus in a repeatable manner, e.g. by a robot, such that their non-ambient temperatures when measured are repeatable. One of the workpieces is measured as a reference workpiece at the non-ambient temperature, and these measurements are compared to calibrated values obtained from an external source, in order to generate an error map or error function. The error map or error function is used to correct measurements of subsequent workpieces of the series which are measured at the repeatable non-ambient temperature.

主权项

1. A method of measuring a series of substantially or nominally identical workpieces, in which each workpiece of the series is received from a manufacturing process and placed on a measuring apparatus, comprising:
(a) measuring one of said workpieces, or an artefact having a plurality of features the size and shape of which approximate said workpieces, on said measuring apparatus at a non-ambient temperature as a reference workpiece, to produce measured dimensional values of the reference workpiece; (b) obtaining calibrated values of said dimensional values from a source external to said measuring apparatus; and (c) generating an error map or look-up table or error function which relates measured dimensional values of the reference workpiece at a non-ambient temperature to the corresponding calibrated values.