Page - 93 - in 3D Printing of Metals

Metals 2016,6, 280 Table1.Cont. Thickness (mm) Load(N) MaximumStress (MPa) MaximumStrain(mm) Weight (g) 2 500 14.705 0.039352 9221000 29.411 0.078705 2.5 500 10.02 0.020339 11411000 18.385 0.043148 It is showninFigures7and8that themaximumstressandstraindecreasewith the increaseof the thicknessof theskin. Thedecrease trendbecomesgentlewhenthe thicknessof theskin isgreater than2mm.Theseresultsallowustoconcludethat themostsuitable thicknessof theskin is2mmto obtaina lightweightcomponentproducedbytheSLMprocess. Figure7.Stressandstrainofskinunder loadof500N. Figure8.Stressandstrainofskinunder loadof1000N. 3.2. PartsDisassemblyandFrameworkDesign Thepartscanbedividedbytheir forceconditionssuchas thebendingmoment, torque, tensile, compression, shearingforceorapossiblecombinationof them.Theshapesof thecomponentsalso needtobeconsidered. Theelementaryshapesof thestructure include: cuboid, cylinder, ring, sphere, Lshapeandsoon. Finally, theauxiliary functionsofeachpart shouldbetaken intoaccount. Thecommonassistant functions include: boltmountinghole,key-way, locationsandsoon. Thepartsweredisassembled as shown in Figure 9. Each divided one should be redesigned for a lighter structure after the disassembly. The topological optimizationof frameworksdesignwasperformedusingOptistruct software (Altair,Troy,NY,USA).Sometypical structureswereredesignedas follows. 93