Flexible Machining System for an Efficient Skin Machining

Aluminum skin milling is a very challenging process due to the high quality requirements needed in the aeronautic and aerospace industries. Nowadays, on these markets, there are just two technological approaches able to face the manufacturing of this sort of wide thin blanks: chemical and mechanical milling by means of highly complex machines. Both solutions lead to a high investment requirement that affect directly on the application profitability on these industrial sectors. This paper presents a flexible machining system that allows milling skin shaped parts within required tolerances by means of an innovative universal holding fixture combined with an adaptive toolpath development. This flexible holding fixture can be adapted to the required shape and can hold uniformly the whole sheet surface. Besides, the solution includes an implementation that can adapt the machining toolpath by means of the skin thickness online measurement. The integration of these two innovative devices allows machining a wide range of low stiffness panels, including different sizes, geometries and curvatures. Moreover, there is no need of readapting the fixture set-up in order to interspersing milling process with trimming and drilling, while one or more separated parts are hold at the same time. On the other hand, since this technological solution has been developed in terms of process efficiency, it allows facing the skin machining with a drastically reduced investment. Hence, this technology turns into a more affordable manufacturing process for industrial suppliers and increases the competitiveness on the aeronautic and aerospace markets.