7 September 2013 Accurately measuring dynamic coefficient of friction in ultraform finishing
Author Affiliations +
Proceedings Volume 8838, Optical Manufacturing and Testing X; 88380U (2013); doi: 10.1117/12.2024494
Event: SPIE Optical Engineering + Applications, 2013, San Diego, California, United States
UltraForm Finishing (UFF) is a deterministic sub-aperture computer numerically controlled grinding and polishing platform designed by OptiPro Systems. UFF is used to grind and polish a variety of optics from simple spherical to fully freeform, and numerous materials from glasses to optical ceramics. The UFF system consists of an abrasive belt around a compliant wheel that rotates and contacts the part to remove material. This work aims to accurately measure the dynamic coefficient of friction (μ), how it changes as a function of belt wear, and how this ultimately affects material removal rates. The coefficient of friction has been examined in terms of contact mechanics and Preston’s equation to determine accurate material removal rates. By accurately predicting changes in μ, polishing iterations can be more accurately predicted, reducing the total number of iterations required to meet specifications. We have established an experimental apparatus that can accurately measure μ by measuring triaxial forces during translating loading conditions or while manufacturing the removal spots used to calculate material removal rates. Using this system, we will demonstrate μ measurements for UFF belts during different states of their lifecycle and assess the material removal function from spot diagrams as a function of wear. Ultimately, we will use this system for qualifying belt-wheel-material combinations to develop a spot-morphing model to better predict instantaneous material removal functions.
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Dennis Briggs, Samantha Echaves, Brendan Pidgeon, Nathan Travis, Jonathan D. Ellis, "Accurately measuring dynamic coefficient of friction in ultraform finishing", Proc. SPIE 8838, Optical Manufacturing and Testing X, 88380U (7 September 2013); doi: 10.1117/12.2024494; https://doi.org/10.1117/12.2024494

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