Basic Experimental Research On Electroforming Of Complex Thin-Walled Parts

Complex thin-walled parts are widely used in aerospace field because of its light weight and highstrength etc. However, thin-walled parts deform easily due to its physical characteristics when usingtraditional ways to process. Electroforming as a nontraditional machining technology has manyadvantages, such as high repetitive forming accuracy, no erosion on tool electrode and non-contactbetween tool and work-piece, etc, which is very suitable to the processing of thin-walled parts.This dissertation will focus on the electroforming of thin-walled parts. The following work hasbeen done:1. Fe-Ni alloys were fabricated on steel substrates by means of pulse electrodeposition in sulfatesolutions. The relation between the properties of deposited films and pulse electrical parameters werestudied. The results are following: The Fe content in the deposit decreased and the microhardnessincreased with increasing duty cycle and peak current density. The pulse frequency had little effect onFe content but led to a slight decrease in microhardness. X-ray diffraction patterns show that thecrystalline phases vary with changes in peak current density and duty cycle but are barely influencedby frequency. When the peak current density or duty cycle is relatively low, crystalline Fe-Ni alloyand pure Fe phases coexist; the pure Fe phases disappear as the peak current density or duty cycleincreases. At still larger peak current densities or duty cycles, crystalline Fe-Ni alloy and pure Niphases coexist.2. Using a circular blade deformation analyzed the influence of polishing-assisted electroformingprocess(FAEP) on the internal stress of Ni electroforming qualitatively. The influence of currentdensity, eletrolyte loop rates and linear velocity of cathode on internal stress has been studied. What’smore, the deformation of thin-walled parts which were machined by polishing-assisted electroformingprocess, decreased effectively with the combination of internal stress and suitable post-treatment.3. Simulated and optimized the shape and using conditions of auxiliary cathode. The resultsindicated that cylindrical cathode has better applicability and effect than flat cathode.4. Based on the study of pulse electrodeposition of Fe-Ni, a suitable pulse parameters were selectedto electroform a thin-walled composite die. The main works are as follows: design the cathode forelectroforming of composite die, simulate and optimize the shape of anode, design the supplementarydevice according to the cathode and anode, electroform a composite die and analyze it’s uniformity.5. Using polishing-assisted electroforming process machine the helicopter anti-corrosion shield. The main works are given as follows: design the cathode, clamp of cathode and electroforming unitbased on the special shape of shield and the characteristics of FAEP, design auxiliary cathode forelectroforming of helicopter anti-corrosion shield according to above simulation and optimization,electroform shield using FAEP and analyze the uniformity through measurement and simulationresults using COMSOL software and discussed the effect of post-processing on the deformation ofshield.