Control of a Thermal Actuator for UP-milling with Multiple Cutting Edges

Ultra-precision (UP) milling processes can be dramatically sped up, and thus made more cost-efficient, by utilizing tools with multiple cutting edges. This, however, requires a dedicated actuating mechanism to interactively control the cutting radius of the individual cutting edges with nanometer precision. This paper presents recent advances in developing a tool holder for diamond fly-cutting that enables the alignment of two or more cutting edges via thermal elongation of the substrate material. After building a comprehensive model of the actuator and verifying it in a static test setup, a closed-loop control was developed that allows setting the elongation in a static setup with nanometer accuracy.