Modelling of contact and friction in aluminium extrusion

A physical model capable of predicting the friction and sticking/slipping lengths in the bearing channel during unlubricated aluminium extrusion processes is presented. The model takes into account the pressure build up in the extrusion direction in relation with the bearing–extrudate friction and how it will be influenced by die geometry such as die angle and bearing length. The results show that a high friction coefficient in the bearing will increase the sticking length and shorten the slipping length. The results are in good agreement with experimental findings documented by previous researches.