Research Of Basic Issues For Multi-direction Layered Forming By Plasma Deposition Manufacturing

Plasma deposition manufacturing (PDM) is a new technology, which is based on rapid prototyping (RP) and can directly and rapidly fabricate functional metal parts with high intensity and full density by the high energy plasma beam. PDM has some advantages, such as high forming efficiency, low cost, good machining flexibility, diversiform kinds of material powder, unlimited shape and size.However, the plasma deposition direct manufacturing also has some technical difficulty in the manufacturing process of the complex parts without support structure. Hence, multi-direction layered manufacturing (MDLM) is introduced to form the complex part without support structure, and can shift to the PDM application areas effectively. In this thesis, a feasible method of MDLM by high energy plasma beam is presented by combining RP, CAD/CAM, numerical control (NC) and multi-direction layered deposition, and some key issues of multi-direction deposition are studied including the slicing algorithm, design and optimization of path, detection of overhanging metric factors, etc. Moreover, verification experiment is carried out by a complex metal part - the double-twist leave.On the basis of the STL model, the author develops the critical algorithms of feature recognition, physical decomposition and slicing, determination of optimal manufacture path, tooling path planning, etc. Through feature recognition and overhanging slicing, decomposed the complex part into sub-components that support each other, realized the algorithm of slicing and path planning respectively, finally generated into CNC's machining G code, thereby the complex part that without support structure could be directly manufactured on multi-aixes machine.The research studied some key issues, including the feature recognition of complex parts, the solid decomposition, the algorithm of slicing, optimization of build direction for parts and path planning, completed the algorithm of the above-mentioned key technology and Verified the correctness of algorithm through concrete example.As the overhanging metric factors decided the character of cell part and the manufacturing method, we tested the factor of a certain material in the research. Aiming at the Plasma Deposition Manufacturing technology, we researched its optimized parameter firstly, based on the parameter, the research tested the overhanging metric factors through experiments. The biggest overhanging gradient angle and offset of the DG.ZJ55T alloy had been found, which offered the gist to decide the type of overhanging, then chose the most rational method to manufacture the metal parts, also a micro-overhang part had been manufactured successfully.In the end, the research studied the defect mechanism of Plasma Deposition Manufacturing, and gave the relevant solutions to the shortcomings. Based on the above researches, the tests adopt the hybrid technology of Plasma Deposition Manufacturing and Milling, realized the double-twisting leaves directly and rapidly.The research offered important technical support to form the complex metal parts by Plasma Deposition Manufacturing and multi-direction layered deposition technology.