Studio, ingegnerizzazione, implementazione e validazione di un sistema di misura basato su di un sensore laser a triangolazione per la lavorazione adattativa di componenti freeform

The work hereby presented represents a conceptual framework for an in-line inspection and adaptive correction in the field of high precision manufacturing of turbomachinery freeform shaped components. A wide perspective on the whole concept is firstly presented, then a deep description, comprehensive of study, engineering and validation experiments, is given on a part of the whole concept. This part consists in an on-board correction system, based on the laser triangulation principle, aiming at the compensation of positioning errors of freeform shaped parts for their machining via Electro Discharge Machining (EDM). The work has been carried out with the cooperation of SARIX SA (www.sarix.com), a Swiss based company, leader in the micro-EDM high precision machines manufacturing. The specific experimental setup comprehensive of machine tool characteristics and technology used for the demonstration, is presented and characterized. Then the sensing equipment choice, together with the design of the specific on-board integration system, are reported. Then the overall procedures designed for the machine tool calibration and positioning are extensively described, together with their governing equations. Since the machining of turbomachinery components is subjected to strict industrial standards, two different procedures have been investigated in order to ensure the full compliancy with these standards: a local adaptive positioning method and a six points constrained one. These two methods have been compared and motivations for the usage of one or another, are reported. The comparison with the actual standard procedure, based on the tactile measurement of some predefined points, was not possible to be reported due to confidentiality issues. Along the work description, the possible error sources, coming for example from the sensing equipment or from its integration system, have been reported and quantified through experimental trials, relatively to the specific equipment used for the experiments. In fact, final results are affected by all the error chain contributions, that must be evaluated in strict relationship with the specific equipment adopted. Finally, overall system tests, comprehensive of both calibration and positioning procedures, have been performed with the described equipment on a custom produced dummy turbine blade, and reported in the present document, together with a few nods regarding real case scenarios (i.e. with real production turbine blades) implementation of the system.