3D Shaping with Tertiary Tool Motion

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The two objectives of this research project are: (1) to conceive an ultra-precision micro/meso-scale machining method for a subclass of three-dimensional free-form surfaces with the concurrent control of their surface topography, and (2) to establish the analytical basis for the process kinematics and cutting mechanics. In the proposed method, primary and secondary motions of a cutting tool are supplemented by a tertiary motion component consisting of controlled small-amplitude closed trajectory motions at ultrasonic frequencies. For the generation of the tertiary motion two alternatives will be explored. The first is based on a piezo-driven two-dimensional flexure design, while the second on a tunable ultrasonic elliptical oscillator. Supporting theoretical work will focus on the analytical formulation of the machine's command sequences for the generation of desired topological features on the surface. Initially, this will be accomplished through geometric and kinematic considerations and later extended to include cutting mechanics related effects such as elastic and plastic deformation, minimum chip thickness influences and others. A prototype machine will be designed, manufactured and tested under different cutting scenarios implemented in conventional and ductile cutting regimes. If successful, the newly conceived micro-cutting process will offer capabilities that cannot be achieved by current competing operations. Its advantages are: (1) very high cutting velocities, (2) ability to impart intricate surface patterns by modulating and phasing the motion components, and (3) creation of sculptured surfaces with controlled topography. The method also offers an alternative to micro-endmilling and eliminates the need for ultra-high-speed low runout spindles. From the scientific standpoint, the combination of theoretical, computational, and experimental methodologies will provide the fundamental understanding of the developed machine's capabilities and of the new processes it executes. Since micro-manufacturing is a fairly new research area, the knowledge base and machine prototype created through this research will provide the necessary educational and physical infrastructure for continued exploration of micro/meso-scale cutting processes.