Experimental Analysis of Circular Milling for Material Identification in Aerospace Industry

In the airplane design, thousand holes should be manufactured by machining leading this process in the first place for process optimization. Recently, the stack materials used in this application are sheet layers of Titanium alloy, Aluminum alloy and CFRP, which normally are machined under different cutting conditions. There are two main solutions when drilling stacks: using the more conservative ones or changing the parameters for each layer. In orbital drilling the forces are lower, with better quality but with longer machining time, compared to drilling, allowing the measurement and control of the process. Smart machining techniques can be applied for recognising and adapting the cutting parameters in real time, depending on a database for decision-making. In this paper, a technique is proposed to identify the cutting material based on the cutting and feed components of the machining force in a circular milling process. Experiments consist of machining separately Titanium and Aluminium alloy workpieces in a similar range of cutting speed and feed, measuring forces and the position of the cutting tool (X,Y, SP) using the machine-tool data. The results show that it is possible to identify the materials using the calculated tangential and radial force components in the tool referential frame because the values of specific cutting and feed force are significantly different for each material. An specific force map is used as a signature to distinguish the materials in real time machining which can be used for orbital drilling in the next step of the research.