Research On Parts With The Shape Of Curvilinear Generatrix And Thin-Wall Part During Spinning Forming Process

Curved, generatrix and thin-wall parts are conical parts with varying half-coneangle, with high requirements in shape and location accuracy. Spinning is the mainprocess of producing this kind of parts, and spinning process design is mainly basedon excursion of the half-cone angle and the limit half-cone angle corresponding tolimit thinning rate of machined materials. As the variation of half-cone angle is outof the limit half-cone angle corresponding to the limit thinning rate of machinedmaterials at normal temperature, it is needed to shape the curved generatrix parts bymultiple cutting and spinning processes.The cutting and spinning process complies with volume-invariable theory andlaw of sine, which has strict restraints on spinning blank-sheets and processparameters. Such factors as the re-installation and location error of spinningblank-sheets and workpiece, the machining error of spinning blank-sheet, the narrowadjustment range of process parameters, the heat-treatment deformation, are allbarriers to curved generatrix thin-wall parts with high tolerance requirements.Based on exensive references, this paper starts from the study on conventionalspinning and forming methods for curved generatrix thin-wall parts, and extends tothe study on the product shape and location accuracy control technology, simplifieddesign of spinning blank-sheet, composite spinning track design, process parametersoptimization, and product organizational performance analysis. It puts forward amachining and forming method for curved generatrix thin-wall parts by combiningheating/composite spinning with numerical control machining process. In thismethod, spinning and forming process is defined as blank-sheet-machining function:numerical control machining is used as a measure to ensure the shape and sizeaccuracy, simplifying the spinning blank-sheet design; heating the material with atemperature lower than the material’s annealing temperature can improve thematerial’s plasticity and decrease its deformation resistance; dual-spinning wheelmirror composite spinning process can improve the force-bearing state duringblank-sheet forming; multiple sectional cutting and spinning with proper connectioncan make blank-sheet tightly compact the outer face of core mould. Application ofmultiple composite spinning track further blurs the boundary of conventional cuttingspinning and ordinary spinning process, making it possible to thin the material aswell as to change blank-sheet shape, compact on core mould and correct shapeduring spinning and forming process, which greatly improves the spinning andforming accuracy and the machining efficiency. Experiments have verified that thismethod makes great sense in guiding the R&D of curved generatrix thin-wall parts machined of materials with good plasticity.