Page - 98 - in 3D Printing of Metals

Metals 2016,6, 280 Accordingto the topologyoptimizationconditionsabove, theoriginalpartmodelwasdefinedas showninFigure17a. The topologyoptimizationmethodwasused toget the frameworkshownin Figure17b. Thefinalstructureafteroptimizationcanbeseen inFigure17c. Thethicknessof frameη wastakenasadesignparameter. Figure17.TheoriginalL-shapemodel (a),L-shapeframeobtainedbytopologyoptimization(b), the finalL-shapeframeafteroptimization(c). 3.3.DetailDesign Therearesomedetailedstructuressuchasthefillet,chamfer,keyway,gearteeth,splines,mounting holeandsoonwhichare importantwhenthepartscooperatewithothercomponents. Toensure the functionsof thesestructures, theyshouldnotberedesigned. After thereconstructionof thestructures, stressconcentrationmayoccurbecauseof thesharp change of the cross-section area caused by the intersecting frame. In order to improve the parts’ performance, the fillets of the frames need to be considered, which can help to reduce the local stressconcentration. Thereare still somepowders in the closedholesof the redesignedpartsmanufacturedby the SLMprocesswhichwill increase theweightandcostof thecomponents. Thus,powderoutlets should beconsideredtodischargepowderssmoothly. ThefilletsandpowderoutletsareshowninFigure18. Figure18.ThefilletsandpowderoutletsofSLMparts. 3.4.Application 3.4.1.Case1: Stopper The stopperwasused in an automatic device to avoid the forwardmovement of this device. Theactual installationanduseconditionsof thispartareshowninFigure19. 98