Investigation on the failure of the gear shaft connected to extruder

In respect to the fracture of the gear shaft of an extruder, the torque on the shaft replaced the fractured one is measured under typical work conditions. The fatigue and material mechanics properties of the fractured shaft are obtained by tensile and fatigue test. Based on the analysis of cyclic fatigue load and the stress of gear shaft, the reason of the shaft fracture is discussed. The analysis indicates that when the extruder is running, high mean stress occurs in the gear shaft, the failure of the gear shaft was caused by fatigue and material strength degradation. Finally, suggestions are given to guide the future operating of the extruder to prevent the gear shaft from fracture.