Influence of surface location within depth of field on measuring by a conoscopic holography sensor integrated in a machining centre

Estudio de la influencia de la posición en el campo de trabajo sobre los resultados de medición de un sensor de holografía conoscópica integrado en un centro de mecanizado.In this work, a Conoscopic Holography (CH) sensor integrated in a Machining Centre (MC) was used for analysing how the measurements taken are influenced by the location of the digitized surface within depth of field (DOF). With this aim, two different digitizing strategies were conducted on a stepped specimen with flat surfaces. In the first strategy each step of the specimen was located at different positions within DOF whereas the CH sensor was kept at a constant height along the scanning of all steps. In the second strategy the sensor height was adapted so that each step was scanned at the same distance within DOF. The comparison between both strategies was performed by calculating the discrepancies between measurements taken by the CH sensor and those obtained by a touch probe (TP) also installed in the MC. Finally, the study provides a series of recommendations for practical application of the sensor.This work is supported by the Spanish Ministry of Economy and Competitiveness and FEDER (DPI2012-30987), the Regional Ministry of Economy and Employment of the Principality of Asturias (Spain) (SV-PA-13-ECOEMP-15) and the Government of the Principality of Asturias through the Programme “Severo Ochoa” 2014 of PhD grants for research and teaching (BP14-049)