Crimping Of Thin-walled Products By Single-point Incremental Forming Processes

As a basic technology of edge forming of thin-walled parts,crimping has been widely used in production.But with the increase of people's individual needs and product update speed,the traditional process is unable to meet the personalized,fast and efficient development of new products and other needs.In order to adapt to the development of the society,it is urgent to develop a rapid,efficient,low cost and flexible forming process.The current study examined a new method for flexibly crimping thin-walled product edges based on the multi-directional dieless incremental forming technology.Al 6061 tubes with outer diameter of 38 mm and thickness of 1.0 mm and plates with thickness of 1mm were employed in the study.Crimping is carried out utilizing modified tools through experiment and simulation.The effects of processing parameters,such as feed rate,tool path and tool shape on the forming results and forming force are discussed.The main conclusions are as follows:(1)Physical experiment and numerical simulation show that outwards and inwards crimping of tube end and plate edge can be executed through the concept of multi-directional dieless incremental forming technology.Compared with the traditional stamping method,there is no dedicate die needed and forming force is much lower.At the same time,the processing chain of incremental forming is further improved.(2)Compared with the traditional stamping method,there are some similar defects,such as fracture,buckling,wrinkling.If the process parameters during incremental forming are not controlled properly,some special defects,including distortion,unevenness,may also occur.In addition,wrinkling is more likely to occur,because the tool will apply asymmetric load to tube end,then local depression will be produced.(3)Tool path has great influence on the forming results.In the incremental crimping of tube end,it is more easily to cause unevenness with circular path than with spiral path.Because it would lead to sudden increase of force when feeding,then decrease in the circumferential processing.The spiral path can avoid the defects and obtain good forming results with good appearance.And,the forming force of spiral path is smaller than it of circular path,when the increment is equal.(4)During the crimping of tube end,the axial and radial force are controlled by the axial and radial increment,fillet radius and radial displacement of tool.Therefore,it is necessary to consider the comprehensive effect of multiple factors in determining the forming parameters and controlling the defects.The phenomenon of warping,horizontal bending and the end effect may occur during the crimping of plate edge,they can be controlled by reducing the increment and improving the geometry of tool.