Research On Flexible Forming Of Sheet Metal With Magnetic Field Controlled Plasma Arc

Flexible forming technique of sheet metal using plasma arc is developed as one of forming technique of sheet metal, which produces deformation of sheet metal by thermal stress and strain induced by scanning of plasma arc on sheet metal. Compared with conventional forming technology of sheet metal, it doesn't cost a lot of time and money to produce mould and die according to the desired shape of the product. Especially, the cost for larger sheet metal will be higher. Therefore, investigation on theory and technology of flexible forming without the need for mould and die contributes significantly to decreasing the high cost and long lead-time. However it is difficult for this technology to produce work piece with large radius and smooth transition curve. By the interaction effect of the magnetic field and plasma, we can control the scanning time of the plasma arc on sheet metal using the adscititious magnetic field in order to get a suitable temperature field and stress field so that the work pieces with large radius and smooth transition curve could be produced. In this paper, the following questions of flexible forming of sheet metal with alternating magnetic field controlled plasma arc based on existing flexible forming technology are studied.1. The movement characteristic of plasma in the magnetic field has been analyzed. And the model of flexible forming of sheet metal with alternating magnetic field controlled plasma arc has been established according to these characteristic. Besides, the research on its formed mechanism has been carried out.2. Programs using the ANSYS parameterization design language (Ansys Parameter Design Language, APDL) have achieved the loading of motion heat source with the Gaussian function distribution, which is the key to realizing dynamic simulation. In the flexible forming process of sheet metal using plasma arc, through the numerical simulation to dynamic change of temperature field and stress field as well as the formed remaining stress and the distortion, the corresponding temperature field and stress field as well as deformation field on various sheet metal are instantaneously obtained. By the analysis of these fields, it is available for the distortion mechanism of the plasma arc flexible forming and the influence rules of sheet metal forming with the function of alternating magnetic field, meanwhile the forming result is predicted.3. The experiment equipment has been set up. The forming rule on flexible forming of sheet metal with magnetic field controlled plasma arc has been studied, at the same time, the influencedegree of the multitudinous factors to the forming are analyzed in the forming process through a few of orthogonal experiment.4. From the research on superficial qualification of formed sheet metal, the defects and their mechanisms in the forming process were analyzed. Meanwhile, some effective defend measures have been advanced.As the experiment result shows, the work pieces with large radius and smooth transition curve could be obtained by flexible forming process of sheet metal with magnetic field controlled plasma arc and the superficial qualification of work pieces are also improved in the process. With the result, the study provides gist in the field of flexible forming technology of sheet metal with magnetic field controlled plasma arc.