Thesebenefitscanbecompellingforarangeoffood-relatedapplications.However,if3Dprintedpartsareintendedforfoodcontactitems,you‘llhavetoconsidersafetypracticesandregulationstoavoidcontactwithtoxicsubstancesandpreventthebuildupofharmfulbacteria.
Foodsafe3Dprintingispossibleandthevarietyofmaterialsapprovedasfoodsafeisincreasing,butthereisahighdegreeofambiguityaroundtheworkflowsandfindingtheappropriateapplicableregulationscanbeachallenge.
Pleasenote
NoFormlabsresinsarefoodsafeunlessuserstakeadditionalsteps.
Tobegin,it’simportanttoclarifyafewkeyterms:
LookfortheselabelsindicatingFDAandEUapproval.Bewarethatamaterialbeing‘compliantwith’doesn’tmeanthatitisexplicitlyapprovedbytheinstitutions,soalwayscheckthetechnicaldatasheetsforacertificate.
TobeconsideredfoodsafeaccordingtotheFDAFoodCode,amaterialhastomeetthefollowingrequirements:
AnyFDAorEUapprovedmaterialincludesnotonlytherawpolymerbutalsotheadditivesormasterbatch.Thesemightcontaincomponentssuchasplasticizers,impactandheatdistortionmodifiers,UV-stabilizers,flameretardants,anti-fouling,anti-static,anti-slip,foamingandclarifyingagents,anti-oxidants,aromaticnucleators,carbonalloys,phosphorescents,fillers,thickeners,chainextenders,metaldeactivators,dyes,andacarrierresin.
A3Dprintedpartcanturnintoapetridishsquirmingwithbacteriawithinweeks.Eventhoughsomematerialswillsurvivethedishwasher,sowilldangerousbacteriasuchasE.coliandsalmonellathatliveinthelittlenooksandcrannies.Sometoxicmoldsfindfavorablegrowthconditionsonseveraltypesofplasticandarehardtoremove.Neithercleaningwithbleachnormicrowavingyourpolymersisanoptionforeliminatinggerms.
Whilebacteriabuildupmightnotbeanissuefordisposableitems,ifyou’replanningtocreateapartforlong-termuse,usingafoodsafecoatingishighlyrecommended.
However,notethatcoatingalsodoesn’tguaranteefoodsafetyforprolongeduseasnotallofthesecoatingsaredishwashersafe,andtheymaydegradeovertime,exposingtheoriginal,potentiallynon-safesurface.
Most3Dprintingmaterialshavealowheatdeflectiontemperature(HDT),whichmeansthatthe3Dprintedpartsmightbecomebrittleandcrack,ordeformandwarpatelevatedtemperatures.Ifyou’replanningtocleana3Dprintedpartinadishwasher,makesuretodoublecheckthatthematerialisdishwashersafeandifthereareanyspecificrecommendationsforwashingtemperature.
Asparticlesmightmigratefromcomponentsofa3Dprinterto3Dprintedparts,itiscrucialthatanycomponentsthatmightcomeincontactwiththe3Dprintingmaterialorthepartarefoodgradeanddonotcontainorleachharmfulchemicals.
Thisincludestakingprecautionswhenusingmultiplematerials,assomematerialspreviouslyusedinthe3Dprintermighthavecontainedtoxicparticlesandmadecontactwithsomecomponents.
Asmaybeexpected,theriskofmigrationishigherifthefoodisexposedtothe3Dprintedpartforanextendedtimeperiod.Ingeneral,trytolimitfoodcontacttimeandtakefurtherprecautionsforpartsthatwillbeincontactwithfoodforlongerperiodsoftime.
Thinkaboutthereasonwhyyou’dliketouse3Dprintingforafoodcontactitem.Ifit’stocreatecustomshapesandforms,inmostcases,thereareindirectwaystouse3Dprintingtocreatethesecustomparts,forexamplewithmolding.Seeanexampleinthenextsection.
SLA3Dprintingusesalasertocureliquidresinintohardenedplasticinaprocesscalledphotopolymerization,resultinginpartsthathavethehighestresolutionandaccuracy,theclearestdetails,andthesmoothestsurfacefinishofallplastic3Dprintingtechnologies.
IsresinfoodsafeTheanswerisno.SubstancesmaymigratefromSLApartswhichmakesnoneoftheresinsandprintedpartsfoodsafebydefault.Whilesomeresinsfordentalandmedicalapplicationsarecertifiedbiocompatible,thatdoesn’tmeanthatthey’refoodsafe.Thesematerialsarecertifiedforspecificapplicationsandshouldnotbeusedforfoodcontactproducts.
Thetoolsandtechniquesforcreating3Dprintedfoodmoldsareeasytomaster,andtheresultsareoftenstunning.
3Dprintedmoldsforthermoformingandsiliconeenabledthecreationofuniqueshapesanddesigns.
Electroplatingistheprocessofcoatingpartswithmetalusinganelectriccurrent.Theprocessismostcommonlyusedfordecorativepurposesortopreventcorrosionbycreatingadurablesurface.
SLApartsareidealforelectroplatingduetotheirsmoothsurfacefinish.However,asplasticsarenonconductivesurfaces,SLA3Dprintshavetoberenderedconductivebycoatingwithgraphite,conductivelacquer,electrolessplate,oravaporizedcoating.
Foodsafemetalcoatingsareavailable,butastheprocessinvolvesvariouschemicals,makingsurethattheworkflowisapprovedforfoodcontactisthedeveloper’sownliability.
Avarietyoffoodsafeglazesareavailableonthemarket,butmakesuretofollowthemanufacturer’sinstructionsinaccordancewithfoodsafetyguidelines.
3Dprintinginceramicsisidealforfabricatingcomplexgeometriesthatwouldn’tbepossiblebyhand.
SeeandfeelFormlabsqualityfirsthand.We’llshipafreesampleparttoyouroffice.
FDMisa3Dprintingprocessthatbuildspartsbymeltingandextrudingthermoplasticfilament,whichaprintnozzledepositslayerbylayerinthebuildarea.
Theextrudedmaterialiscircularincross-section,whichleavesverynarrowcrevicesinbetweenlayerswithadepthdirectlyproportionaltolayerheight.Itisrecommendedinanycasetoprintatthelowestfeasiblelayerheightforfoodsafeparts.
Consequently,themainchallengewithFDMpartsisavoidingthebuildupofbacteria.Tobetrulyfoodsafeinthelongterm,anFDM3Dprintneedstohaveasmoothsurface.Chemicalsmoothingwithsolventslikeacetone,d-Limonene,orethylacetateremovesmanyoftheirregularitiesoftheprintresultinginasmooth,glossyappearance.However,applyingasubsequentfoodsafecoatingisstillhighlyrecommended.
LayersshowingonFDM(left)andSLA(right)3Dprints.
Foodgradefilamentsdonotcontainanycompositeparticlessowillnotweardownthenozzleintotheprint.Nevertheless,avoidbrassnozzlesthatcontainleadanduseadedicatedstainlesssteelnozzleinsteadforallfoodcontactitems.
Alwayscheckthecompatibilityofyour3Dprinter’scomponentswiththefilament.Forexample,PEIisamaterialthatisFDAcompliantandoffersgreatmechanicalbenefitsbutneedstobeprocessedatover300°C,whichrequiresaspecificprintersolution.
ThemostcommonquestionsaroundFDMfoodsafetyconcerntwopopularmaterials.IsPLAfoodsafeIsABSfoodsafeTheansweris,itdepends.
Foodsafe3DprintingfilamentsincludePLA,PP,co-polyester,PET,PET-G,HIPS,andnylon-6,aswellassomebrandsofABS,ASA,andPEI.HavingtorunpartsthroughthedishwasherrulesoutPET,nylon,andPLAbecausetheseplasticssoftenanddistortaround60–70°C.Forapplicationsinvolvinghotliquids,co-polyester,HighTemperaturePLAorPEIaremostsuited.
Whilenotreflectedintheregulations,somestudiessuspectthatpolystyrenemayleachstyrenes,co-polyestersmightcausehealthconcernsandthatfoodgradeFDMfilamentsmightlosetheirsafestatusduetooxidationandthermaldegradationfromtheprintingprocess.
Note:Pleasenotethatdatainthistableissubjecttochange.
SelectiveLaserSinteringisa3Dprintingprocessthatuseahigh-poweredlasertofusesmallparticlesofpolymerpowder.Themostcommonmaterialforlasersinteringisnylon,apopularengineeringthermoplasticwithexcellentmechanicalproperties.
WhilesomeSLSpowdersaregradedfoodsafe,theparticlesonthesurfaceofprintedpartsmightnotfusecompletely,resultinginpartsthatareinherentlyporousanddonotdealwellwithmoistureandmoldgrowth.Eventhoughthenylon12powdercanbesteamcleanedinanautoclave,itisbesttocoatSLSpartswithfoodsafecoatingstosealtheirsurface.
Acommonpost-processingstepforSLSpartsisdying.ButnotethatafteranSLSparthasbeendyed,thedyemayleachintotheprintedpartwhichrenderstheitemnotfoodsafe.
Foodsafetywith3Dprintingisnotasimplematterthatwillboildowntoaclearyesornoanswer.Producing3Dprintedpartsforfoodcontactitemsrequirescarefulconsiderationoftherisksdependingontheirintendeduse.
Forfurtherinformationonfoodsafetyand3Dprinting,werecommendreadingthefollowing: