Failure Analysis And Structure Improvement Research Of Fuel Pump

This project of research focuses on a quality issue in the real assembly production of a new turbine fuel pump developed by a company. Because the normal development process cannot make the customer satisfied, The R&D department finally decided to make modification on a mature product, they called this redesign. By this way, we can shorten the development cycle at the most extent, because we save the time of components development, production line reforming, plastic components mold and casting dies design and making, assembling fixture design and making. Finally, the development work was finished; the new project came into trial run stage. Quality issue occurred in the first trial run, we had high reject rate during the production, most of the scrap pumps had similar failure mode. The result of tear-down analysis and components measurement cannot help us find out the root cause of the issue. Considering the urgent delivery date, company establishes a task force to solve the problem.What this article mainly describes is the research thought and content on the quality issue, also the approach and method used in the research work. The whole research work goes through the failure mode description, data collection and analysis, cause investigation and assumption, verification of assumption by digital simulation methods, construction optimization and effect verification. In the stage of cause investigation, we use fishbone diagram which are popularly used to find out the root cause in manufacturing company. By means of the brain storm method, team member list as many as possible potential reasons of the failure mode. Then, we exclude one by one the potential reasons with measurement and experiment approach, finally lock the root cause or propose the assumption. In the stage of digital simulation, we use the software of finite element analysis, named ANSYS, its contact analysis function help us to research the structural statics of assembly. We simulate the stress and strain of the key components after press-in assembling, then we get the result of deformation state and value, the simulation result can verify the assumption which we proposed before.Our research shows the cause of the failure mode is that the pump casing became plastic deformation after pressed into the outer shell. It causes the pump casing cannot provide enough space for turbine impeller working, the impeller is touched by top and bottom surface, the resistance is impeding the driving force the armature provides, as a result, the pump is failed in performance test. In the stage of construction optimization and effect verification, all the previous research result provides the basis for process parameter adjustment and component construction optimization, and improvement result is verified by digital simulation again.Base on the research process and result, R&D department realizes the importance of using digital simulation in product development. So using digital simulation method for verification, are key elements to ensure the work go smoothly. Facing to fierce market competition, company must always introduce new to market and be faster than opponents; the digital simulation technique is playing an important role.