Research On The Rapid Prototyping Technology And Forming Process Of Aluminum Alloy Based On The CMT

By stacking materials layer to layer, physical models and molds machining canbe achieved with the characteristics of short production cycle, saving materials andproduction flexibility. It is more sutiable for production diversity and thehigh-update speed, and it can also improve the production efficiency and thedevelopment of the technology.The rapid prototyping system with cold metal transfer technology which iscontrolled by automatic robot system is built, that can achieve the low-cost andsolve the welding problem during the ace-forming process. By using the rapidprototyping system, the rapid prototyping technology of5356aluminum alloy isstudied. The study shows that the rapid prototyping system can achieve theautomatic forming of the complex-shape samples and control the robot walkingtracks and the welding parameters, which achieved the aluminum alloy specimenswith high-accuracy and complex shape.First, the welding methods’ impact on the shaping trajectory is studied. Theresults show that CMT achieved the moderate width and height. And preheat processcan improve the specimens formation and achieve the suitable welding width andheight.The welding parameters’ impact on the columnar shaped specimen is studied.The results showed that with the welding current increasing, the apparent conditionis significantly improved and the diameter of the columnar specimens graduallyincreases. With the wire elongation increasing, the apparent condition and protectiveeffects firstly increase, and after the wire elongation get12mm, the protectiveeffects decreases and the porosity defects increase. With the height of welding torchincreasing, the uniformity of the specimen firstly increases and then decreases. TheCMT forming method can achieve the specimen of the uniform appearance and goodprotective effect while the pulse CMT and AC CMT achieve the specimens withporosity defects. The mechanical properties of cylindrical shaped specimens canreach131MPa. The fracture center mainly shows brittle fracture characteristic, andthe periphery of the fracture shows the ductile fracture characteristic.The further study on the relationship of the forming process and the samplesperformance shows that the cooling time during the interlayer is essential and thesuitable cooling time can improve the shaping efficiency and shaping accuracy.Constantly changing the arc-start position could improve the dimensional accuracyof specimens and the sample’s mechanical properties in parallel direction are betterthan that in the vertical direction. By solution treatment, the samples’ mechanical properties are improved, especially in the vertical direction. The fracture in thedirection parallel to the forming direction shows the brittle fracture characteristic,and in the vertical direction the fracture shows the ductile fracture characteristic.The forming method by using rapid prototyping with cold transfer technologycan form the solid material samples, analysis the samples’ accuracy, efficiency andforming condition. The study on the marine trefoil propellers with the rapidprototyping verify the possibility that arc rapid prototyping work in formingcomplex specimen.