A model to transform a commercial flatbed scanner into a two-coordinates measuring machine

This paper describes a methodology which allows a commercial flatbed scanner to be transformed into a two-coordinate measuring machine which is capable of providing traceable measurements. This methodology requires an initial adjustment in order to convert the reference system of the flatbed scanner into a Cartesian reference system, thereafter calibrating it using standards with metrological traceability. Circle and line scales have been used in this case, but other alternative standards may also be employed by merely adapting the calculation algorithms. Once the equipment has been calibrated, the characterisation process of a relatively complex part and the results obtained for different critical dimensions are indicated as an example. The criteria used to determine and propagate the uncertainties in measurement, as recommended in Supplements 1 and 2 to the “Guide to the expression of uncertainty in measurement” (GUM), are also indicated.