Adaptive process planning of rapid prototyping and manufacturing for complex biomedical models

摘要

In this research, a set of novel, integrated and systematic adaptive process planning algorithms and strategies, which include adaptive tool-path generation algorithms and strategies, adaptive slicing algorithms and strategies, adaptive approach for FGM(Functionally Graded Material)-based biomedical model and build time and geometrical accuracy analysis and control modules, for complex biomedical model fabrication in the RP/M (Rapid Prototyping and Manufacturing) process, have been developed to balance and optimise the geometrical accuracy and build efficiency.In the developed adaptive tool-path generation algorithms and strategies, directly slicing algorithm and NURBS(Non-Uniform Rational B-Spline)-based curves have been developed to represent the boundary contours of the sliced layers to maintain the geometrical accuracy of original biomedical models. The developed mixed tool-path generation algorithm can be used to generate mixed contour and zigzag tool-paths to preserve geometrical accuracy and speed up fabrication. Based on the developed build time and geometrical accuracy analysis modules, the developed adaptive speed algorithms can be used to further reduce build time of biomedical model fabrication in RP/M.In the developed adaptive slicing approach, rotating slicing and two thresholds have been introduced to extract surface feature of biomedical models. Then, an adaptive slicing thickness determination algorithm has been developed to decide the thickness of each slicing layer based on the outside surface complexity of the model. In addition, the user can balance the geometrical accuracy and the build efficiency during RP/M processing with the different values of two pre-setting thresholds. Furthermore, by choosing the right value of the pre-setting thresholds, it can also effectively reduce the build time and improve the accuracy of biomedical model fabrication in RP/M. In the developed adaptive approach for FGM-based biomedical model fabrication, FGM-based modelling features can represents typical FGM-based biomedical models effectively, and the linear and non-linear control parameters for FGM composition and distributions can enable users to address their specific functional needs of FGM-based biomedical model. The proposed mixed tool-path generation algorithm and adaptive speed algorithm can be used to generate a series of contour/offset tool-paths to represent the material gradual change, and zigzag tool-path is generated for the internal area of a single material to support the realizable and customized FGM-based biomedical models fabrication in RP/M efficiently.