Influence of Operating Variables During Flow Forming Process

Abstract

Flow forming is gradually employed in production of high precision seamless components in the field of aerospace and defense. Rocket & missile casing, rocket motor case, cartridge case, rocket nose cones are few examples of flow forming process. The nature of process is non linear with complex deformation behavior. There are mainly two strategies used during the process viz. forward and backward/reverse. In forward method, the direction of roller feed and material deformation is same and in reverse method, the direction of roller feed and material deformation is opposite. Usually there are three force components encountered during the process i.e. axial, radial and circumferential. The understanding and knowledge of forces are crucial for tooling design for various geometrical and material conditions. The online force measurement during the process is quite difficult in commercial machines. Therefore, a simulation model is developed to estimate forces during the process. Taguchi L9 design has been used to develop the model because it is a well established design of experiment method to solve complex and time consuming problems. Three levels of three operating variables (rotational speed, axial feed and depth of forming) along with friction factor have been used during the study. The material utilized as Aluminum Alloy 6063 due to its light weight, excellent corrosion resistance, recyclable, cost effectiveness, ease of availability, durability etc. It has been observed that axial force is found to be highest followed by the radial and circumferential force. Also it has been discerned that axial feed and friction factor are the most prominent factors affecting axial and circumferential forces during the process. Further, radial force is influenced by friction factor only. The effect on von mises stress and equivalent plastic strain also studied and reported.