The current requirement of precision on freeform surface machining, as well as productivity necessities which facilitate the supply of high quality products to the market, have promoted an important progress on integration of machining and inspection stages on machining centers. On Machine Measuring techniques (OMM) stand out among these advances, which aim at integration on production machines of contact and non-contact inspection technologies, traditionally used on coordinate measuring machines (CMM). Nevertheless, application of these techniques show a series of problems such as those regarding to the surface accessibility for digitizing, precision and operational speed, for which there is no a wholly satisfactory answer yet, from an industrial point of view. Therefore, enhancements on precision and operating speed for on-machine inspection, by improving the current techniques or by the introduction of new ones, constitute the main challenges of future in the field of OMM. Taking this into account, the present Project aims at evaluating the advantages and disadvantages of a non-contact technique named Conoscopic Holography, applied for on-machine inspection of freeform surfaces. This way, it is intended to design and implement a system based on conoscopic sensors, to integrate it into a 3 axis machining center and to compare -based on productivity and precision- the information acquired by the system with that provided by a standard on-machine inspection system using touch trigger probes. Likewise, information from both systems will be compared with reference models obtained on a CMM with a touch trigger probe, under laboratory conditions. Surfaces generated by milling will be used as testing specimens, which must be representative of models of common parts in the industrial application of machining centers, such as sheet metal dies and complex surfaces of turbine blades.