Learn Metal 3D Printing: How Metal FFF Works - Markforged

These metal 3D printers are a highly specialized variation of FFF printers, optimized to print MIM (metal injection molding) feedstock. Skiptonavigation Learn Blog HowtheMetalFFF3DPrintingProcessWorks Metalfusedfilamentfabrication(FFF)isthemostaccessible,easytouse,andaffordabletypeofmetal3Dprintingtechnology.Asaresult,arangeofindustries—suchasaerospaceandautomotive—havealreadytappedintometalFFFfor3Dprintingfunctionalparts.MetalFFFisbasedaroundmetalinjectionmolding(MIM),andusesathree-stepprocess:print,debind,andsinter.Readthisblogposttolearnwhatgoesonineachkeystepofthis3Dmetalprintingprocess. MetalFFF's3-StepPrintingProcess Thesemetal3DprintersareahighlyspecializedvariationofFFFprinters,optimizedtoprintMIM(metalinjectionmolding)feedstock.Thistypeofprintingcreates“green”metalpartsthatmustbedeboundandsinteredbeforefinaluse. These“green”partsarealwaysscaledup15-20%fromthefinalpartdimensionstoaccountforrepeatableandpredictableshrinkageduringsintering.Printing:metalpowderboundinplasticisprintedalayeratatimeintotheshapeofyourpart.Partsarescaleduptocompensateforshrinkageduringthesinteringprocess,resultingin“green”parts.Debinding:Afterprinting,greenpartsareplacedintothedebindingstation,whereanorganicsolventisusedtodissolvemostoftheplasticbindingmaterial.Afterwashing,greenpartsareknownas“brown”parts.Sintering:Washed“brown”partsarethenplacedinafurnace,wheretheyareheatedwithamaterial-specificprofile—firsttoburnawayremainingbinder,thentosolidifymetalpowderintoafinishedpart. Step1:Printing MetalFFF3DprintingtechnologiesuseaprocessthatisnearlyidenticaltoconventionalFFFprinters.TheonlymaindifferenceisthatmetalFFFprintersuseavacuum-sealedprintsheet,ratherthanaconventionalprintbed. Forusers,theprintingprocessincludes:SlicingpartsonasoftwareplatformPlacingavacuum-sealedprintsheetontheprintbedInitiatingthemetal3DprintingprocessRemovingtheprintedpartaftervacuumdisengagesPeelingthe“green”partofffromtheprintsheetDualExtrusionwithMIMFeedstock:ThesetypesofprintersextrudeMIMfilamentinonenozzle,andceramicinterfacefilamentintheother.OneextrusionnozzleisdesignedtoprintMIMfeedstock,whichisametalpowderboundinatwo-partplasticbindingmaterial.Thisisthematerialusedtoformthepartitself,aswellasthesupportsandraft.Forindustrial3Dprintermetal,Markforgedcurrentlyofferssixdifferentcommercial-gradeofferings—A2toolsteel,D2toolsteel,Inconel625,Copper,H13toolsteel,and17-4PHstainlesssteel. Theothernozzleprintsceramicreleasematerial.Thisprovidesthesurfacebetweenpartsandtheirsupportsandrafts.Withoutthisreleasematerial,3Dprintingmetalpartsthatrequiresupportswouldnotbepossible.Thesinteringprocessturnsthismaterialintopowder,whichenablestheparttobeeasilyseparatedfromsupports. End-usemetalpartsprintedin17-4stainlesssteel. Step2:Debinding Thedebindingstepremovesthemajorityofthebindingmaterial.Theresultisa“brown”partreadyforsintering. First,the“green”partisfirstplacedintoaheatedsolventbathinawashstationusingadegreasingsolutiontodissolvetheprimarybindingmaterial.MarkforgedmetalFFFmachinesusetheWash-1,asolventbaseddebindingsolution.ItprimarilyusesOpteonSF-79asasolvent,ahigh-performancefluiddesignedtooffersuperiorcleaningpower,higherefficiency,andsafetyinanenvironmentallysustainableway. Overall,thedebindingprocessformetalFFFisfairlysimpleandonlyrequiresbasicPPE.Userstepsforthedebindingprocessinclude:AddinggreenpartstoawashingbasketLoweringitintothemachinewiththesolventandclosingthelidOpeningthelidafterwashing,andremovingthepartsfromthewashingbasketPlacingthepartsinanairdryingchamberinthewashstationRemovingthepartsfromthewashstationstationoncethepartsaredriedSo,whathappenstoapartduringwashing?Thedebindingsolventbathdissolvestheprimarybindingmaterialinthegreenpart.Asitdissolvesbindingmaterial,thesolventopensupmicroscopicfluidpathwaysintothepart,whichenablesthesolventtoflowdeeperanddissolvemore. Finishedstainlesssteelpartsareremovedfromthesinteringfurnace. Step3:Sintering Sinteringisthecriticalfinalstepofthismetaladditivemanufacturingprocess. Sinteringremovesthe“brown”partsfromthedebindingstep,burningouttheremainingbinder,andthensinteringthepartatanearmeltingtemperature.Allofthisisdoneinaprecise,controlledatmosphere.Theautomatedprocessisextremelycomplexandrequiresprecisecontrolofahighenergyenvironment.Thesinteringprocessinvolvesseveralkeystages.First,thepartisheatedtoanintermediarytemperaturetoburnouttheremainingbindingmaterial—whichexitsthepartthroughthemicro-pathwayscreatedduringthesolventdebindingprocess.Second,thepartisheatedtothesinteringtemperaturewhereitshrinksfromthelarger“green”or“brown”sizetothefinalsizeofthe3Dprintedfunctionalpart.Solidgeometriescoalesceto95%+porositywhiletheclosedcellinfillremains.Theceramicinterfacematerialturnstodust,whichenablesuserstoeasilyseparatethe3Dprintedmetalpartfromtheraftandsupports. Usingasinteringfurnacerequiresthefollowingsteps:AddingpartstothesetterplatePlacingthesetterplateintothefurnaceClosingthefurnacedoorStartingthesinteringprocessRunningtheprocesstocompletion FreeMetal3DPrintingResources Metal3DPrintingFundamentals E-Book:MetalFFFApplicationsandCaseExamples ComprehensiveGuidetoMetalFFF AlloftheblogsandtheinformationcontainedwithinthoseblogsarecopyrightbyMarkforged,Inc.andmaynotbecopied,modified,oradoptedinanywaywithoutourwrittenpermission.Ourblogsmaycontainourservicemarksortrademarks,aswellasofthoseouraffiliates.Youruseofourblogsdoesnotconstituteanyrightorlicenseforyoutouseourservicemarksortrademarkswithoutourpriorpermission.MarkforgedInformationprovidedinourblogsshouldnotbeconsideredprofessionaladvice.Weareundernoobligationtoupdateorreviseblogsbasedonnewinformation,subsequentevents,orotherwise. Nevermissanarticle SubscribetogetnewMarkforgedcontentinyourinbox required Submit Thanks!