| Bound abrasive grinding of optical materials with CNC (Computer Numerical Control) machining equipment can achieve precise control over product configuration. However, optimization of the process and its effective use in difficult grinding situations requires improved understanding of the behavior and role of grinding tools. In this document, research directed toward developing this improved understanding is outlined.; As a first step, a model is developed relating tool performance (load/energy required for material removal), machine characteristics (stiffness), process parameters ("feeds and speeds"), and grinding geometry to the amount and distribution of material removed during grinding. It is found that the ability of the grinding tool to remove material in the programmed fashion can be related to a single parameter combining the tool, machine, process, and geometrical parameters. Application of the model to both ring-tool generation (appropriate for spherical surface) and contour grinding (for asphere generation) is demonstrated.; Experimentally, a force sensing spindle has been developed and used to measure the required grinding load under "normal" operating conditions (both work and tool spindles rotating). This unit has been used to measure tool performance in terms of the loads required for material removal and to study the effects of changes in infeed rate and tool speed. Tool surfaces have also been quantitatively characterized using optical profilometry and the evolution of tools during grinding has been studied in terms of grinding load, surface topography, and wear rate. Future work will concentrate on understanding and modeling these effects and their correlation. |
