Process and Tool development to deburr cross-drilled holes

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The aim of the project is the TRIZ- (Teorija Reschenija Isobretatjelskich Zadatch - Theory of Innovative Problem Solving) based development of new tool concepts, cutting edge geometries and methods for a reliable and automated deburring of cross-drilled holes. The TRIZ-based development method is a systematic and structured approach to solve technical problems. The prerequisite of this research project is a deeper understanding of the relationship between the intersection curve and the cutting edge geometry. This will be achieved through a complete mathematical description of the intersecting curves of cross-drilled holes with varying diameter, a misalignment between the axes of the holes as well as rotations of the pre-drilled hole. Subsequently, the gradients of the intersecting curves as well as entering strategies through the pre- or cross-drilled holes will be analyzed. The gradients vary strongly for different intersecting curves as well as along the circumference of an individual intersection, thus giving rise to the common problem existing deburring tools encounter when removing the entire root of the burr. A sphere represents all gradients and can be used in combination with a synchronized guide along the track to compensate the different gradients along the intersecting curve. Therefore a possible approach could be the use of a sphere- or sickle-shaped cutting edge. The implementation of a model used to predict the height of the burr along the circumference of the intersecting curve prevents the bending of large burrs. The efficacy of the method is based on the deburring process starting in areas of low burr formation. This method contributes to a reliable burr-removal. Based on the derived mathematical equations to describe the intersections of the holes, the deburring tool will be moved along the intersecting curve to remove the burr. Therefore a tool-based and a numeric control-based approach will be combined to achieve a synchronized movement of the tool and the intersecting curve. Subsequently, experimental investigations on the influence of different entering strategies, feed rate and cutting speed on the secondary burr height will be conducted. The final year of the research project focuses on the development of a model to identify the operating range of the deburring tool and to investigates the effects of the micro- and macrogeometry of the cutting edge on the secondary burr.