Failure Analysis And Finite Element Simulation Of Melt Gear Pump

Melt gear pump is an important component of the large extrusion pelleting machine,suitable for high temperature and high viscosity of the polymer melt conveying,pressurization,metering,make its not affected by pressure and temperature conditions change.Pump with pressure between extrusion machine and mold,and can match the parameters of the extrusion machine,the output increase and tolerance requirements strictly to provide uniform melt.Due to the different material composition will change gear,the shear stress between the rapid rise in gear pump motor torque,gear wear and cracks within its service life,etc.The main research object of this experiment is Dalian granulating CME-450 plastic machinery factory production of gear pump,gear pump in the work of motor torque rise rapidly.After testing experiment found that gear crack and in different parts of the gear face serious wear and tear.This experiment combined with microhardness tester,optical microscope(OM),scanning electron microscope(SEM)analysis of materials such as pollution and the cause of the crack of gear pump;And use Ansys software simulation analysis on the stress distribution,the gear pump with the experimental results to confirm each other,come to a conclusion as follows:1.According to the results,it showed that gear axle parts found no perfoliate crack so material pollution is not a refrigerant leakage pollution.2.The grinding phenomenon occurs at the top of tooth,the tooth surface and the root and the temperature exists in it,so that the tissue near the tooth root changes.3.Through the finite element simulation and analysis of the gear rotor bending stiffness is insufficient,cause equipment appeared in the process of running from the friction wear and friction calorific value of design standards,resulting in material high temperature cracking formation pollution materials,form a vicious circle.4.In the use of gear pump and processing material should be analyzed before the material liquidity is match the shear stress of the gear pump,less liquid polymer(HDPE-1158)is not suitable for this kind of processing methods.