| Selective laser melting(SLM)is one type of metal additive manufacturing technology that can produce metal parts in a layer-to-layer manner.Different processing parameters affect the microstructures of parts and further the mechanical properties.On the other hand,different processing parameters also affect the working status of the laser and galvanometer system,which directly relates to the electrical energy consumption.The relationship of processing parameters,mechanical properties,and electrical energy consumption was studied in this study in order to decrease the electrical energy consumption with fulfilled requirements of properties.In this study,316L stainless steel was used as the materials and all the SLM processing were performed using a Renishaw(UK)AM250.The research mainly includes the following contents:In chapter 1,the research background,significance of this study and a literature review current research are introduced.SLM technology and its advantages are presented.Finally,the overall framework and experimental equipment used in this paper are listedIn chapter 2,the influences of two SLM processing parameters including the laser power and exposure time on the electric energy consumption is studied.The relationship between electric energy density and process energy consumption is also investigated.In chapter 3,the effects of laser power and exposure time on the mechanical properties including tensile strength,bending strength,torsion strength,hardness,density and wear resistance are studied from the macro and micro levels.In chapter 4,the growth rate is introduced to evaluate the effects of processing parameters,mechanical properties and electrical energy consumption.The target is to achieve low electrical energy consumption by controlling processing parameters under the fulfilled mechanical properties.In chapter 5,gradient processing based on SLM technology is presented based on a case study of a SLMed hydraulic valve body.The tribology performance is studied by the tribology experiments to simulate the contact behaviors between a hydraulic valve body and a spool.The strength of the valve body is also studied through both the experiments and simulation.The processing parameters are optimized and the low electrical energy consumption is achieved with the fulfilled strength and tribology performance.On the other hand,a lightweight structure of valve body is designed based on a porous lattice structure which improves the efficiency and reduces electric energy consumption in SLM process.Based on the above experiments,the hydraulic valve body is finally fabricated using SLM.Chapter 6 summarized the work of this study and the future work is also presented. |
