Design and development of a flow forming machine

Abstract

Flow forming is an advanced version of metal spinning process which is used to manufacture sheet metal products having symmetrically axial geometry and also to produce long thin-wall tubes with precision dimensions and desired mechanical property. In flow forming of tubes, the workpiece is held onto the mandrel as the forming roller moves along the workpiece axially to reduce the diameter. Author has developed a few concepts of flow forming tool that built to accommodate the lathe tool post. One of the concept consists of two rollers set has been fabricated. This tool is rigid enough to perform flow forming at lathe machine and can flow-form tubes with a diameter up to 100mm. This tooling assembly is attached at Pinacho SP/165 conventional lathe machine to perform flow forming process. The selected work material is aluminium alloy 6061 that widely applied at light-weighted industries. The main objectives of this research is to analyse the influences of major process parameters such as feed rate, spindle speed and depth of cut on wall thickness changes, internal diameter growth and roundness of the finished products. The dimensions of the finish products are measured using Carl Zeiss Coordinate Measuring Machine. It is found that wall thickness changes decreases and external diameter increases as the roller travels along the tube. It is also found that higher feed rate of rollers and lower thickness reductions have advantages for obtaining smaller internal diameter growth. The tube with good roundness also can be obtained by flow-form the tube using lower thickness reductions. Material structure test also has been conducted to confirm the direction of the flow of material during the process.