P. Díaz-Rodríguez¹, J.A. Santiago¹, A. García-Carrero^1,2, I. Fernández-Martínez¹, A. Wennberg¹, P. Collignon³, A. Guzmán⁴, D. Sanmartín⁴, M.A. Monclús², J.M. Molina-Aldareguia^2,4
1Nano4Energy SL, Madrid, Spain
²IMDEA Materials Institute, Madrid, Spain
³SAS PD2-I, Paris, France
⁴Universidad Politécnica de Madrid, Madrid, Spain
The high standards and requirements demanded in high-speed machining (HSM) applications – some examples are the precise manufacturing of IC Molds or biomedical devices - comprise a delicate control of the tool preparation as well as coatings design and finish, especially in the case of microtools with a diameter below the millimeter. The work developed covers not only the coating step, but also the preparation of the tool, focusing on:
a) Microtool cutting edge preparation.
b) HiPIMS deposition, as the use of this technology allows the preparation of hard coatings with high smoothness, low density of defects, and good homogeneous coverage of 3D intricate parts (thus able to match the low tolerances required for micromachining) makes this technology ideal for these applications. The tested coatings are based on Si- and B- containing AlTiN and were deposited in different sets of tools, according to their specific requirements, attaining hardness values of 35 GPa and good adhesion. Moreover, oxidation studies were performed to determine the stability of these coatings, analysing, and comparing the results in terms of SEM, TEM, and XRD, observing a greater oxidation resistance for the Al containing coatings.
c) Machining tests, which, in addition to mechanical properties analysis, provide information regarding the performance of the coatings under operation conditions. The materials selected for machining are Hardened Steel (HRC60) and Ti₆AlV₄ alloy, and the finishing of the machined parts, as well as the wear suffered by the tool is analyzed.