Misure di rumore su autocollimatore di progetto LUMINAR

Nel contesto del progetto Euramet-EMRP JRP LUMINAR, una delle fasi preliminari ha richiesto la verifica delle performances dell’autocollimatore, che è una delle parti essenziali di quello che è previsto come set up finale (Figura 1) dell’apparato dimostratore. Tale apparato, costituito fondamentalmente da una lente e da un sensore ottico, è deputato a misurare l’imbardata e il beccheggio del carrello che trasla sullo stadio lineare per inseguire il bersaglio retroriflettore (Figura 2). Scopo del presente lavoro è quello di quantificare il rumore da cui sono affette le acquisizioni della camera installata sull’autocollimatore, in presenza di diverse configurazioni hardware.In the context of the Euramet-EMRP JRP LUMINAR project, one of the preliminary stages required the assessment of the autocollimator performances: this is one of the fundamental components of the final set up (Figura 1), and is essentially composed by a collimating lens and a digital sensor capable of acquiring images; positioned at the end of the linear stage, its purpose is to measure the actual misalignment of the undeflected beam and then the yaw and pitch of the equipment that is translated along the axis to follow a retro-reflecting target (Figura 2). The aim of this work is to quantify the noise affecting the digital images captured by the autocollimator camera, in different hardware configurations

Taratura autocollimatore di progetto LUMINAR

Allo scopo di effettuare una taratura dell’autocollimatore utilizzato nell’esperimento LUMINAR, si è allestito presso il laboratorio Angoli dell’INRiM un set up ad hoc, che ha previsto l’impiego di una testa ottica per lanciare un laser che funge da riferimento per generare, opportunamente focalizzato, degli spot su una coppia di camere, e una tavola rotante sulla quale collocare l’autocollimatore, così da quantificare la risoluzione angolare di questo.In order to calibrate the auto-collimator employed in the Euramet-EMRP JRP LUMINAR project, I equipped a specific set up in the Angular reference laboratory at INRiM; this set up consisted of an optical head used to generate a laser beam (focalized in small spots on a pair of cameras by means of two collimating lenses), and a rotating table where the auto-collimator assembly was fixed; the rotating table was aimed to explore suitable angles for the determination of the auto-collimator resolution

Taratura autocollimatore di progetto LUMINAR

Allo scopo di effettuare una taratura dell’autocollimatore utilizzato nell’esperimento LUMINAR, si è allestito presso il laboratorio Angoli dell’INRiM un set up ad hoc, che ha previsto l’impiego di una testa ottica per lanciare un laser che funge da riferimento per generare, opportunamente focalizzato, degli spot su una coppia di camere, e una tavola rotante sulla quale collocare l’autocollimatore, così da quantificare la risoluzione angolare di questo.In order to calibrate the auto-collimator employed in the Euramet-EMRP JRP LUMINAR project, I equipped a specific set up in the Angular reference laboratory at INRiM; this set up consisted of an optical head used to generate a laser beam (focalized in small spots on a pair of cameras by means of two collimating lenses), and a rotating table where the auto-collimator assembly was fixed; the rotating table was aimed to explore suitable angles for the determination of the auto-collimator resolution

1D measurement of coordinates in space: a novel apparatus

A novel instrument to measure the coordinate of a point in space is presented. It does so in isolation, i.e. without the aid of similar devices measuring the other coordinates, as it is usually the case with other coordinate instruments. The eventual goal is to achieve a full 3D measurement by replicating the device three times orthogonal to each other, with a target uncertainty of 50 μm over a volume of (10 x 10 x 5) m³ in harsh conditions

Dynamics modeling of CMM probing systems

The probing system dynamics is important for coordinate measuring machine (CMM) performance, particularly when probing in scanning mode. This is a typical situation e.g. in gear metrology, where the flanks are typically scanned. This may occur even without full awareness of the user, who may accept default values or choose with little understanding. This work presents a modelling of a contouring probe. The model is based on the characteristics of real probes; more specifically, continuous passive systems are considered, resulting essentially in second order 3D systems. The theoretical model is validated experimentally by scanning suitable surfaces exhibiting a range of slopes. The separation between static and dynamic effects is achieved by repeating the experiments at varying scanning speed, so that a same geometrical slope results in different temporal slopes – which the probing system dynamics is sensitive to. The model is oriented to define a good trade-off between the scanning speed and the measurement uncertainty

Investigation on Modulation-Based Straightness Measurement

The concept of a novel non-contacting technique for measuring straightness and its practical realization in a mechanical device are presented in this article. The device, called InPlanT, is based on the acquisition of the luminous signal retroreflected by a spherical glass target and impinged on a photodiode after mechanical modulation. The received signal is reduced to the sought straightness profile using dedicated software. The system was characterized with a high-accuracy CMM and the maximum error of indication was derived

The Influence of Scanning Parameters on CMM Measurements

This work shows the results of Deliverable5.2.3-JRP ENG56 DriveTrain about “validation of measurement strategies and determination of achievable measurement uncertainty in industrial environment”. Deliverable refers to investigation of dynamic behaviour of probing systems due to scanning measurement at CMM of two standard involute profiles, both superposed with a certain waviness. INRIM investigated the influence of scanning parameters such as different scanning speeds, workpiece orientations inside the measurement volume and stylus lengths. Measurement results have been analysed in order to evaluate the profile deviations (Fa, ffa and fHa) according to ISO1328-1:2013 and the influence due to the scanning measurement parameters on these results. Moreover, a spectral analysis has been performed using FFT method and the three main components of the spectrum have been calibrated in terms of wavelength and amplitude