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metals Article CaseStudiesonLocalReinforcementofSheetMetal ComponentsbyLaserAdditiveManufacturing MarkusBambach1,*,AlexanderSviridov1,AndreasWeisheit 2 and JohannesHenrichSchleifenbaum2,3 1 MechanicalDesignandManufacturing,BrandenburgUniversityofTechnologyCottbus-Senftenberg, Konrad-Wachsmann-Allee17,03046Cottbus,Germany;sviridov@b-tu.de 2 Fraunhofer Institute forLaserTechnologyILT/Chair forLaserTechnologyLLT,RWTHAachen, Steinbachstraße15,52074Aachen,Germany;andreas.weisheit@ilt.fraunhofer.de (A.W.); johannes.henrich.schleifenbaum@ilt.fraunhofer.de (J.H.S.) 3 DigitalAdditiveProduction,RWTHAachen,Steinbachstraße15,52074Aachen,Germany * Correspondence: bambach@b-tu.de;Tel.:+49-355-69-3108 AcademicEditor:ManojGupta Received: 31December2016;Accepted: 20March2017;Published: 25March2017 Abstract: This paper details two case studies thatmake use of lasermetal deposition for local reinforcementof sheetmetal components. Twobenchmarkscenariosare investigated,bothusing aluminumalloys: (i)using lasercladdingto increase thestiffnessofapre-formedcomponent,and (ii) applying a local claddingon sheetmetal for increasing the thicknessprior to ahole-flanging operation. Theresults showthatbothroutesareviable.Applyingcladdingsontosheetmetalbeforea metal formingoperationmustensuresuitable formability,whichmaybelimitedbythe layermaterial andundesiredchanges in themicrostructureof thesheet. The limitedformabilityhas tobetakeninto account in thedesignof the formingoperation.Claddingontoalreadyformedcomponentshas to copewith inevitabledistortionof thecomponent.Nevertheless, introducingadditivemanufacturing into thefieldofsheetmetal formingopens thepossibility toproducenewproductssuchas tailored laser-claddedblanks, combinationsofsheetandbulkcomponentsandtodevelopnewmethodssuch asstiffnessmanagement in lightweightdesign. Keywords: tailoredblanks;additivemanufacturing; laserdepositionwelding 1. Introduction In many applications, local reinforcement of sheet metal components may be necessary or desired,e.g.: • tosupporthighly loadedareas thatbear fastenersor joints; • tocreate functionalelements; • tocompensate forsheet thinningoccurringduringmetal formingoperations; • tomanufactureparts forvehiclederivatives fromseriesparts; • foracoustic reasonsor • forcorrosionandwearprotection. Figure1showsatypicalapplicationwherea local reinforcementwouldbeuseful to improve the performanceof thecomponentwithout resorting toasheetmetalof increasedthickness. Therivetnut inFigure1acouldbereplacedbyaformedflange(createdbyahole-flangingoperation) intowhich a thread iscut. This solutionwouldsaveweightandreduce theriskofcorrosionattack. Replacing the rivet nut by a formed flange is only feasible if the flange provides sufficient sheet thickness. Flangingoperations,however, typically leadtosheet thinning,asshowninFigure1b. Metals 2017,7, 113 131 www.mdpi.com/journal/metals