Embedding of Micro Thin Film Sensors Into Polycrystaline Cubic Boron Nitride (PCBN) for Potential Tooling Applications Via Diffusion Bonding

Polycrystalline cubic boron nitride (PCBN) is increasingly being used in manufacturing processes to increase tool life and processing speed. Existing sensors in PCBN tools are unable to provide accurate time- and space-resolved measurements of the thermo-mechanical phenomena at and near the tool-work interface. Using microfabrication techniques along with diffusion bonding, thin film palladium-13wt% chromium (PdCr) alloy micro strain gage sensors were successfully embedded into PCBN structures for potential tooling applications. This article reports on the design, fabrication and characterization of a sensor consisting of three PdCr sensing elements embedded into a PCBN sample. The embedded sensors show good linearity and sensitivity.