Research On Deep Hole Machining Mechanism And Cutting Parameter Optimization For Marine Diesel Engine Key Parts

With the constant progress of technology and rapid development of industry, deep holemachining technology has been applied more and more widely. In deep hole machiningprocess, because of the special environment of machining that machining tool andworkpiece in a closed or semi-closed state, cutting heat is far more than common turning. Atpresent, cutting mechanism, temperature distribution in cutting area and heat dissipation indeep hole machining have not been further analyzed and studied, resulting in cuttingparameters are too conservative, and seriously affects machining efficiency. This study is onthe background of enterprise basic technology research project "Research on the keytechnology in body and cylinder head machining of marine high-power medium speeddiesel engine", the research status of deep hole machining technology at home and abroadwere analyzed and summarized. On this basis, deep hole machining mechanism and cuttingparameter optimization for marine diesel engine body were researched. The main contentsof the thesis are as follows:(1) cutting heat generation in deep hole machining process was analyzed in theory,thermal model of deep hole drilling was established, cutting heat was analyzed andcalculated, the distribution of tool temperature field was derived, the main factors affectingthe cutting heat were analyzed, and providing the theory basis for the next step of finiteelement analysis.(2) In order to study the problems of heat produce and distribution further in deep holemachining process, model of the deep hole drilling was established, the factors of modelsimplification, mesh optimization and parameter setting that affecting simulation efficiencyand quality were discussed.16sets of simulation experiment were designed by usingorthogonal experiment, a certain type of marine diesel engine body deep hole drillingmachining process was simulated dynamically by the metal plastic forming simulationsoftware Deform-3D, drilling temperature in deep hole machining process was obtained, theinfluences of different cutting parameters to drilling temperature were analyzed andcompared.(3) For the problem of heat dissipation in deep hole machining process, numericalsimulation of gun drill cooling system was done by numerical analysis Fluent software. Theflow condition of single-phase flow coolant was simulated firstly, physicalcharacteristics(pressure, velocity, turbulent kinetic energy) in channel flow were obtained to provide the basis for the motion law of the chip in the flow field. Then two-phase flow ofchip and coolant was simulated and analysed, the particle trajectory and law of chip insteady state was obtained, the two factors of entrance pressure and cutting equivalentdiameter affecting cooling system were analysed.(4) Based on the above theoretical study, aiming at the problem of low efficiency,cutting parameter optimization algorithm based on particle swarm algorithm was putforward according to deep hole machining characteristics of marine diesel engine body. Thedefinition of constraints in optimization problems were completed combined with theperformance parameters of machining system requirements, and the deep hole cuttingparameters were optimized by using MatLab software. Finally, the field processing test wasdone to verify the feasibility of the theory and method.