| The goal of this project was to integrate surface condition representation, processing motion generation, and material removal/deposition models for surface manufacturing processes requiring highly repetitive, non-regular motion. Currently, the models used for these three stages in surface manufacturing processes are incompatible and are adapted for specific activities: design, process planning and production. The goal here was to study ways to unify these models and to represent the results analytically. It was desired that the resulting integrated system be applicable to a variety of surface processing technologies employing highly repetitive tool motion, including both material removal processes (grinding, polishing, etc.) and material deposition process (painting, rapid prototyping, plasma deposition and laser deposition, etc.). Other novel aspects of this project were to be able to generate highly repetitive processing tool motion based on surface condition (shape, waviness, roughness, etc.) and to be able to establish a relationship between surface condition error and surface roughness as a function of time.; A new way of generating processing tool path motion that can mimic manual processing motion has been developed and is described in this report. First, potential fields are built on the surface based on the surface condition. Then processing tool path motion is generated based on these potential fields. The processing tool path generated using potential fields will tend to avoid areas with low potential (low removal/deposition requirements) and will tend to be concentrated in areas with high potential (high removal/deposition requirements). As the tool moves, the representation that is used to describe the surface condition is modified according to a material removal/deposition model. Consequently, this modifies the potential fields of the surface and influences the motion of the processing tool.; During the finishing processes, the areas with highest surface condition error on the surface tend to be reduced first until the surface error is relatively uniform. Then the surface is further processed until the surface error is within a specified value. A relationship between processing tool path motion generation, surface condition representation, and the material removal/deposition model has been established. The final result of the surface manufacturing process is the accumulated effect of repeated machining with a large number of non-regular passes rather than traditional single pass generation.; Other issues considered include introducing practical constraints on processing tool path motion (e.g. bounds on velocity of the tool), and computing time complexity of the tool motion generation method using potential fields, surface condition representation, and material removal/deposition models. When integrated, it is shown that simplified system models can be used to predict the results, eliminating the need to model the complexity of the multitude of individual tool passes. |
