Computer controlled system for dieless drawing of tool steel bar

This paper describes the computer controlled processing of AISI-O1 steel rod by a dieless drawing method. Both the operation of a purposely built machine and the results of an experimental programme are described. The machine consisted of elements to provide a drawing force, a PID controlled band heater and an air/water cooling system to carry out the novel bar production process. The untreated material in bar form of initial diameter, 5 mm, was drawn in the temperature range of 600–750 °C at drawing velocities of 2.5–5 mm/min and with air-cooling provided in the pressure range 2–4 × 105 Pa. The process ratio, i.e. the ratio of the drawing velocity to the heat/cooling device movement velocity was varied between 0.35 and 1.33. A novel load-control algorithm was executed to ensure a steady-state process and a high tolerance on the final drawn diameter.