Study On Optimizing Technology About Digital Manufacturing For Thin-walled Surface Part

With the wide application of thin-walled surface parts, design and processing of thin-walled surface parts has become a hotspot of digital design and manufacturing(CAD/CAM) development and applications. A thin-walled surface part has complex shape, long processing cycle and poor rigidity. It’s easy to deform and difficult to deformation-compensate and clamp. Thin-walled surface part CNC machining is the research focus in the field of digital manufacturing. This thesis is about further research on thin-walled surface part CNC programming, CNC machining processes and surface jig.Traditional NC tool path is discontinuous or continuous with more pointed transit, which are bottleneck problems seriously restricting high speed machining cutting performance. Against those problems, this thesis proposes a composite spiral tool path generation method for high-speed machining. To attain high-speed machining necessary cutting stability, complex free-form surfaces are subdivided into “flat surface”, “flat top and steep side”, “ flat surfaces top and steep side” and “composite steep surface”, and etc.. According to their different shape characteristics and process characteristics, composite spiral tool path with different structures are developed to meet the demanding requirements of high-speed machining for a variety of complex-shaped free surface, solve effectively chatter and vibration in high-speed machining, and improved significantly processing efficiency and precision of thin-walled surface parts.Against deformation in surface construction of reverse engineering, with constructing deformation compensating surface as core, conventional deformation compensating technology, reverse engineering and CNC five-axis CAM technology are combined. Spline fitting technology optimization aimed to thin-walled surface deformation compensating, surface reconstructing technology optimization and CAM programming based on surface 3D compensating are proposed. Surface error compensating and CNC programming are integrated. Surface deformation compensating accuracy and CAM programming efficiency are improved largely.Against lack of efficient adaptive fixture of thin-walled surface part, there’s some effort to develop multi-pointed annular surfaces self-adaptive fixture for annular thin-walled blanks and multi-pointed surface self-adaptive vacuum fixture for thin-walled surface housing parts. Multi-pointed surface self-adaptive fixture combines the advantages of mechanical structures and hydraulic structures, doubling the number of the contact point compared with the traditional fixture. A multi-pointed floating function in structures has been achieved. There are high adaption in shape and high efficiency in clamping, so that requirements for the free surface parts quick clamping in automated production line will be met. Finite element analysis and actual results show that self-adaptive fixture meet requirements for the free surface parts quick clamping in automated production line.The research results of the thesis are thin-walled surface part high-speed machining technology, thin-walled surface 3d deformation compensation technology and new methods and tools provided by multi-pointed surface self-adaptive fixture applications...