Analysis of flash formation in continuous rotary extrusion of copper

Flash formation is an important technological issue in continuous extrusion of copper. Flash build-up has adverse machine loading effects and therefore the flash must be shaved off from the wheel surface. This results in 5–25% material losses and extra costs from operator time spent clearing excess from the machine and disposal of the scrap. The present work aims to explain the mechanics of flash formation in continuous rotary extrusion. An analytical model is developed for estimating the flash shape and the amount of scrap based on geometrical factors and frictional properties. The proposed method is verified by comparison with experimental findings and with FE-simulation results.