The need to satisfy a market that is more oriented to accurate and repeatable dimensional measurements, especially in the energy field, where performance is critical, has led us to design and build a machine with 6 axis and two machines with 5-axis CNC for polishing turbine blade profiles.
A machine of this type does not exist in the market, aside from an industrial robot, whose rigidity and repeatability of position affect the accuracy of machining. Indeed, by way of example, it is noted that some profiles require up to ±0.05 mm tolerance which is not easily attainable with an industrial robot.
Since the early '60s, the difficulty of polishing such complex profiles with an abrasive belt has meant that this work was done by hand by true "artisans" specialized in polishing the blades. Polish affects the finished product, not only in terms of size but also aesthetics.
Firstly, the blade rotation is completely dependent on its point of contact with the belt, thus reducing significantly the compensation of the linear axis and improving the aesthetic profile of the product. Another peculiarity is of course the measurement system of the semi-finished product. This machine is equipped with a probe, able to "study" the thickness of the piece solely in order to steer the subsequent processing. Only in this way, as a result of the polishing, is it possible to optimize the quality of the final product.
Finally, the polishing process is speeded up through the preparation of two abrasive belts, a pre-finishing and finishing, which can be replaced even during operation of the machine, therefore not slowing the production cycle.
Even the difficulty of finding CAD / CAM software for this type of processing has been overcome by developing our own software internally perfectly able to meet the unique kinematics of our prototype.