Thin Walled Machining Optimization for Additive Manufactured Components

Additive Manufacturing (AM) is an arising production process due to the possibility to produce monolithic components with complex shape with one single process and without the need of special tooling. AM produced parts still often require a machining phase, since their surface finish is not compliant with the strict requirements of the most advanced market, such as aerospace, energy, defense, where these technologies are becoming the leading-edge option to produce small batches of complex parts. Since the reduced weight is a key requirement for these parts, they are characterized by thin walls and webs, representing a challenge in the machining phase. These thin features have usually low stiffness, requiring the usage of low productivity machining parameters. The idea of this paper is to set up an approach able to predict the dynamics of a thin walled part produced using AM. The knowledge of the workpiece dynamics evolution throughout the machining process can be used to carry out cutting parameters optimizations with different objectives, such as to avoid the glitches characterized by the high vibrations of the workpiece in stable cutting conditions, or to avoid the occurrence of chatter vibration. The developed system uses a Finite Element (FE) analysis to predict the workpiece dynamic behavior during the machining process, updating its changing geometry. The FE model of the AM product is automatically created starting from the G-code used in the AM operation. The developed solution can automatically optimize the G-code for the machining operation, generated by any CAM, updating feed and spindle speed in accordance with the selected optimization strategies. The developed approach was tested using as a test case a NACA airfoil.