Abstract

Metal sheet spinning is a process where a piece of sheet metal is spun about its axis, while a tool is moved into it to gradually form it into an axisymmetric product – rather like pottery spinning, but with sheet metal. However, if the tool is not controlled carefully, the target product will not be formed accurately, or worse, it will wrinkle up or tear. Conventionally a skilled workman, with only an intuitive understanding of the process, would manually control the tool, watching the part and adapting his approach as he forms it. We have tried to automate this by fitting various sensors onto our spinning machine, and use only simple structural models within a closed-loop control system to work out how to adapt the motion of the tool. I will give a case study where this approach has worked, and one where it hasn’t, and discuss the trade-off between the accuracy of these simple models and the time to compute them.