1、外文翻译原文PRINTINGPROCESSESMATERIALSOURCEHTTP/SPRINGERLIBTSINGHUAEDUCN/CONTENT/U10J303213G520P0/AUTHORIANGIBSON；DAVIDWROSENPRINTINGTECHNOLOGYHASBEENEXTENSIVELYINVESTIGATED,WITHTHEMAJORITYOFTHATINVESTIGATIONHISTORICALLYBASEDUPONAPPLICATIONSTOTHETWODIMENSIONALPRINTINGINDUSTRYRECENTLY,HOWEVER,ITHASSPREADTO
2、NUMEROUSNEWAPPLICATIONAREAS,INCLUDINGELECTRONICSPACKAGING,OPTICS,ANDADDITIVEMANUFACTURINGSOMEOFTHESEAPPLICATIONS,INFACT,HAVELITERALLYTAKENTHETECHNOLOGYINTOANEWDIMENSIONTHEEMPLOYMENTOFPRINTINGTECHNOLOGIESINTHECREATIONOFTHREEDIMENSIONALPRODUCTSHASQUICKLYBECOMEANEXTREMELYPROMISINGMANUFACTURINGPRACTICE,
3、BOTHWIDELYSTUDIEDANDINCREASINGLYWIDELYUSEDTHISCHAPTERWILLSUMMARIZETHEPRINTINGACHIEVEMENTSMADEINTHEADDITIVEMANUFACTURINGINDUSTRYANDINACADEMIATHEDEVELOPMENTOFPRINTINGASAPROCESSTOFABRICATE3DPARTSISSUMMARIZED,FOLLOWEDBYASURVEYOFCOMMERCIALPOLYMERPRINTINGMACHINESBOTHDIRECTPARTPRINTINGANDBINDERPRINTINGTECH
4、NOLOGIESAREINTRODUCEDDIRECTPRINTINGREFERSTOPROCESSESWHEREALLOFTHEPARTMATERIALISDISPENSEDFROMAPRINTHEAD,WHILEBINDERPRINTINGREFERSTOABROADCLASSOFPROCESSESWHEREBINDEROROTHERADDITIVEISPRINTEDONTOAPOWDERBEDWHICHFORMSTHEBULKOFTHEPARTSOMEOFTHETECHNICALCHALLENGESOFPRINTINGAREINTRODUCEDMATERIALDEVELOPMENTFOR
5、PRINTINGPOLYMERS,METALS,ANDCERAMICSISINVESTIGATEDINSOMEDETAILFROMTHETOPICOFPUREPRINTINGTECHNOLOGIES,WEMOVETOTHETHREEDIMENSIONALBINDERPRINTINGPROCESS,WHEREBINDERISPRINTEDINTOAPOWDERBEDTOFORMAPART71EVOLUTIONOFPRINTINGASANADDITIVEMANUFACTURINGPROCESSTWODIMENSIONALINKJETPRINTINGHASBEENINEXISTENCESINCETH
6、E1960S,USEDFORDECADESASAMETHODOFPRINTINGDOCUMENTSANDIMAGESFROMCOMPUTERSANDOTHERDIGITALDEVICESINKJETPRINTINGISNOWWIDELYUSEDINTHEDESKTOPPRINTINGINDUSTRY,COMMERCIALIZEDBYCOMPANIESSUCHASHPANDCANONLE1PROVIDESATHOROUGHREVIEWOFTHEHISTORICALDEVELOPMENTOFTHEINKJETPRINTINGINDUSTRY711HISTORICALDEVELOPMENTOF3DP
7、RINTINGPRINTINGASATHREEDIMENSIONALBUILDINGMETHODWASFIRSTDEMONSTRATEDINTHE1980SWITHPATENTSRELATEDTOTHEDEVELOPMENTOFBALLISTICPARTICLEMANUFACTURING,WHICHINVOLVEDSIMPLEDEPOSITIONOF“PARTICLES”OFMATERIALONTOANARTICLE2THEFIRSTCOMMERCIALLYSUCCESSFULTECHNOLOGYWASTHEMODELMAKERFROMSANDERSPROTOTYPENOWSOLIDSCAPE
8、,INTRODUCEDIN1994,WHICHPRINTEDABASICWAXMATERIALTHATWASHEATEDTOLIQUIDSTATE3IN1996,3DSYSTEMSJOINEDTHECOMPETITIONWITHTHEINTRODUCTIONOFTHEACTUA2100,ANOTHERWAXBASEDPRINTINGMACHINETHEACTUAWASREVISEDIN1999ANDMARKETEDASTHETHERMOJET3IN2001,SANDERSDESIGNINTERNATIONALBRIEFLYENTEREDTHEMARKETWITHITSRAPIDTOOLMAKE
9、R,BUTWASQUICKLYRESTRAINEDDUETOINTELLECTUALPROPERTYCONFLICTSWITHSOLIDSCAPE3ITISNOTABLETHATALLOFTHESEMEMBERSOFTHEFIRSTGENERATIONOFRPPRINTINGMACHINESRELIEDONHEATEDWAXYTHERMOPLASTICSASTHEIRBUILDMATERIALTHEYARETHEREFOREMOSTAPPROPRIATEFORCONCEPTMODELINGANDINVESTMENTCASTINGPATTERNSBINDERPRINTINGMETHODSWERE
10、DEVELOPEDINTHEEARLY1990S,PRIMARILYATMITTHEYDEVELOPEDTHE3DPRINTING3DPPROCESSINWHICHABINDERISPRINTEDONTOAPOWDERBEDTOFORMPARTCROSSSECTIONSCONTRASTTHISCONCEPTWITHSLS,WHEREALASERMELTSPOWDERPARTICLESTODEFINEAPARTCROSSSECTIONARECOATINGSYSTEMSIMILARTOSLSMACHINESTHENDEPOSITSANOTHERLAYEROFPOWDER,ENABLINGTHEMA
11、CHINETOPRINTBINDERTODEFINETHENEXTCROSSSECTIONAWIDERANGEOFPOLYMER,METAL,ANDCERAMICMATERIALSHAVEBEENPROCESSEDINTHISMANNERSEVERALCOMPANIESLICENSEDTHE3DPTECHNOLOGYFROMMITANDBECAMESUCCESSFULMACHINEDEVELOPERS,INCLUDINGZCORPANDEXONETHISDISCUSSIONWILLBECONTINUEDINSECT76MORERECENTLY,THEFOCUSOFDEVELOPMENTHASB
12、EENONTHEDEPOSITIONOFACRYLATEPHOTOPOLYMER,WHEREINDROPLETSOFLIQUIDMONOMERAREFORMEDANDTHENEXPOSEDTOULTRAVIOLETLIGHTTOPROMOTEPOLYMERIZATIONTHERELIANCEUPONPHOTOPOLYMERIZATIONISSIMILARTOTHATINSTEREOLITHOGRAPHY,BUTOTHERPROCESSCHALLENGESARESIGNIFICANTLYDIFFERENTTHELEADINGEDGEOFTHISSECONDWAVEOFMACHINESARRIVE
13、DONTHEMARKETWITHTHEQUADRAFROMOBJETGEOMETRIESOFISRAELIN2000,FOLLOWEDQUICKLYBYTHEREVISEDQUADRATEMPOIN2001BOTHMACHINESJETTEDAPHOTOPOLYMERUSINGPRINTHEADSWITHOVER1,500NOZZLES3IN2003,3DSYSTEMSLAUNCHEDACOMPETINGTECHNOLOGYWITHITSINVISION3DPRINTERMULTIJETMODELING,THEPRINTINGSYSTEMUSEDINTHISMACHINE,WASACTUALL
14、YANEXTENSIONOFTHETECHNOLOGYDEVELOPEDWITHTHETHERMOJETLINE3,DESPITETHECHANGEINMATERIALSOLIDIFICATIONSTRATEGYTHECOMPANIESCONTINUETOINNOVATE,ASWILLBEDISCUSSEDINTHENEXTSECTION72RESEARCHACHIEVEMENTSINPRINTINGDEPOSITIONWHILEINDUSTRYPLAYERSHAVESOFARINTRODUCEDPRINTINGMACHINESTHATUSEWAXYPOLYMERSANDACRYLICPHOT
15、OPOLYMERSEXCLUSIVELY,RESEARCHGROUPSAROUNDTHEWORLDHAVEEXPERIMENTEDWITHTHEPOTENTIALFORPRINTINGMACHINESTHATCOULDBUILDINTHOSEANDOTHERMATERIALSAMONGTHOSEMATERIALSMOSTSTUDIEDANDMOSTPROMISINGFORFUTUREAPPLICATIONSAREPOLYMERS,CERAMICS,ANDMETALSTHISSECTIONHIGHLIGHTSACHIEVEMENTSINTHOSERESEARCHAREAS721POLYMERSP
16、OLYMERSCONSISTOFANENORMOUSCLASSOFMATERIALS,REPRESENTINGAWIDERANGEOFMECHANICALPROPERTIESANDAPPLICATIONSONLYASMALLFRACTIONOFTHATRANGEISREPRESENTEDBYTHEMACHINESDISCUSSEDINSECT71ANDALTHOUGHPOLYMERSARETHEONLYMATERIALCURRENTLYUSEDINTHEPRINTINGINDUSTRY,THERESEEMSTOBERELATIVELYLITTLEDISCUSSIONONPOLYMERINKJE
17、TPRODUCTIONOFMACROTHREEDIMENSIONALSTRUCTURESINTHEPUBLISHEDSCIENTICLITERATUREGAOANDSONIN7PRESENTTHERSTNOTABLEACADEMICSTUDYOFTHEDEPOSITIONANDSOLIDICATIONOFGROUPSOFMOLTENPOLYMERMICRODROPSTHEYDISCUSSNDINGSRELATEDTOTHREEMODESOFDEPOSITIONCOLUMNAR,SWEEPLINEAR,ANDREPEATEDSWEEPVERTICALWALLSTHETWOMATERIALSUSE
18、DINTHEIRINVESTIGATIONSWEREACANDELILLAWAXANDAMICROCRYSTALLINEPETROLEUMWAX,DEPOSITEDINDROPLETS50MMINDIAMETERFROMAPRINTHEAD35MMFROMACOOLEDSUBSTRATETHEAUTHORSRSTCONSIDERTHEEFFECTSOFDROPLETDEPOSITIONFREQUENCYANDCOOLINGONCOLUMNARFORMATIONASWOULDBEEXPECTED,IFTHEDROPSAREDEPOSITEDRAPIDLY50HZINTHISCASE,THESUB
19、STRATEONWHICHTHEYIMPINGEISSTILLATANELEVATEDTEMPERATURE,REDUCINGTHESOLIDICATIONCONTACTANGLEANDRESULTINGINBALLLIKEDEPOSITIONSINSTEADOFCOLUMNSFIG72ANUMERICALANALYSESOFTHERELEVANTCHARACTERISTICTIMESOFCOOLINGAREINCLUDEDGAOANDSONINALSOCONSIDERHORIZONTALDEPOSITIONOFDROPLETSANDTHESUBSEQUENTFORMATIONOFLINEST
20、HEYPROPOSETHATSMOOTHSOLIDLINESWILLBEFORMEDONLYINASMALLRANGEOFDROPLETFREQUENCIES,DEPENDENTUPONTHESWEEPSPEED,DROPLETSIZE,ANDSOLIDICATIONCONTACTANGLEFIG72BFINALLY,THEYPROPOSETHATWALLLIKEDEPOSITIONWILLINVOLVEACOMBINATIONOFTHERELEVANTASPECTSFROMEACHOFTHEABOVESITUATIONSREISETAL8ALSOPROVIDESOMEDISCUSSIONON
21、THELINEARDEPOSITIONOFDROPLETSTHEYDEPOSITEDMOLTENMOBILWAXPARAFNWAXWITHAHEATEDPRINTHEADFROMSOLIDSCAPETHEYVARIEDBOTHTHEPRINTHEADHORIZONTALSPEEDANDTHEVELOCITYOFDROPLETIGHTFROMTHENOZZLEFORLOWDROPLETSPEEDS,LOWSWEEPSPEEDSCREATEDDISCONTINUOUSDEPOSITIONANDHIGHSWEEPSPEEDSCREATEDCONTINUOUSLINESFIG73ACHIGHDROPL
22、ETIMPACTSPEEDLEDTOSPLASHINGATHIGHSWEEPSPEEDSANDLINEBULGESATLOWSWEEPSPEEDS73TECHNICALCHALLENGESOFPRINTINGASEVIDENCEDBYTHEINDUSTRYANDRESEARCHAPPLICATIONSOFPRINTINGDISCUSSEDINTHEPREVIOUSSECTION,PRINTINGALREADYHASASTRONGFOOTHOLDINTERMSOFBECOMINGASUCCESSFULAMTECHNOLOGYTHEREARE,HOWEVER,SOMESERIOUSTECHNICA
23、LSHORTCOMINGSTHATHAVEPREVENTEDITSDEVELOPMENTFROMFURTHERGROWTHTOIDENTIFYANDADDRESSTHOSEPROBLEMS,THERELEVANTPHENOMENAANDSTRATEGICAPPROACHESTAKENBYITSDEVELOPERSMUSTBEUNDERSTOODINTHENEXTTWOSECTIONS,THETECHNICALCHALLENGESOFTHEPRINTINGPROCESSAREOUTLINED,THEMOSTIMPORTANTOFITSLIMITATIONSRELEVANTTOTHEDEPOSIT
24、IONOFFUNCTIONALPOLYMERSAREIDENTIFIED,ANDHOWTHOSELIMITATIONSARECURRENTLYADDRESSEDISSUMMARIZEDPRINTINGFORTHREEDIMENSIONALFABRICATIONISANEXTREMELYCOMPLEXPROCESS,WITHCHALLENGINGTECHNICALISSUESTHROUGHOUTTHEFIRSTOFTHESECHALLENGESISFORMULATIONOFTHELIQUIDMATERIALIFTHEMATERIALISNOTINLIQUIDFORMTOBEGINWITH,THI
25、SMAYMEANSUSPENDINGPARTICLESINACARRIERLIQUID,DISSOLVINGMATERIALSINASOLVENT,MELTINGASOLIDPOLYMER,ORMIXINGAFORMULATIONOFMONOMERORPREPOLYMERWITHAPOLYMERIZATIONINITIATORINMANYCASES,OTHERSUBSTANCESSUCHASSURFACTANTSAREADDEDTOTHELIQUIDTOATTAINACCEPTABLECHARACTERISTICSENTIREINDUSTRIESAREDEVOTEDTOTHEMIXTUREOF
26、INKSFORTWODIMENSIONALPRINTING,ANDITISREASONABLETOASSUMETHATINTHEFUTURETHISWILLALSOBETHECASEFORTHREEDIMENSIONALFABRICATIONTHESECONDHURDLETOOVERCOMEISDROPLETFORMATIONTOUSEINKJETDEPOSITIONMETHODS,THEMATERIALMUSTBECONVERTEDFROMACONTINUOUSVOLUMEOFLIQUIDINTOANUMBEROFSMALLDISCRETEDROPLETSTHISFUNCTIONISOFTE
27、NDEPENDENTUPONAFINELYTUNEDRELATIONSHIPBETWEENTHEMATERIALBEINGPRINTED,THEHARDWAREINVOLVED,ANDTHEPROCESSPARAMETERSANUMBEROFMETHODSOFACHIEVINGDROPLETFORMATIONAREDISCUSSEDINSECT731SMALLCHANGESTOTHEMATERIAL,SUCHASTHEADDITIONOFTINYPARTICLES23,CANDRAMATICALLYCHANGEITSDROPLETFORMINGBEHAVIORASWELL,ASCANCHANG
28、ESTOTHEPHYSICALSETUPATHIRDCHALLENGEISCONTROLOFTHEDEPOSITIONOFTHESEDROPLETSTHISINVOLVESISSUESOFDROPLETFLIGHTPATH,IMPACT,ANDSUBSTRATEWETTINGORINTERACTION2428INPRINTINGPROCESSES,EITHERTHEPRINTHEADORTHESUBSTRATEISUSUALLYMOVING,SOTHECALCULATIONOFTHETRAJECTORYOFTHEDROPLETSMUSTTAKETHISISSUEINTOACCOUNTINADD
29、ITIONTOTHELOCATIONOFTHEDROPLETSARRIVAL,DROPLETVELOCITYANDSIZEWILLALSOAFFECTTHEDEPOSITIONCHARACTERISTICS,ASMENTIONEDINSECT72,ANDMUSTBEMEASUREDANDCONTROLLEDVIANOZZLEDESIGNANDOPERATIONTHEQUALITYOFTHEIMPACTEDDROPLETMUSTALSOBECONTROLLEDIFSMALLERDROPLETS,CALLEDSATELLITES,BREAKOFFFROMTHEMAINDROPLETDURINGFL
30、IGHT,THENTHEDEPOSITEDMATERIALWILLBESPREADOVERALARGERAREATHANINTENDEDANDTHEDEPOSITIONWILLNOTHAVEWELLDEFINEDBOUNDARIESINTHESAMEWAY,IFTHEDROPLETSPLASHESONIMPACT,FORMINGWHATISCALLEDA“CROWN,”SIMILARRESULTSWILLOCCUR29ALLOFTHEEFFECTSWILLNEGATIVELYIMPACTTHEPRINTQUALITYOFTHEPRINTEDMATERIALCONCURRENTLY,THECON
31、VERSIONOFTHELIQUIDMATERIALDROPLETSTOSOLIDGEOMETRYMUSTBECAREFULLYCONTROLLEDASDISCUSSEDINSECT72,DIRECTPRINTINGRELIESONAPHASECHANGEOFTHEPRINTEDMATERIALEXAMPLESOFPHASECHANGEMODESEMPLOYEDINEXISTINGPRINTINGTECHNOLOGIESARESOLIDIFICATIONOFAMELTEDMATERIALEG,WAX,SOLDER,EVAPORATIONOFTHELIQUIDPORTIONOFASOLUTION
32、EG,SOMECERAMICAPPROACHES,ANDCURINGOFAPHOTOPOLYMEREG,OBJET,PROJETMACHINESOROTHERCHEMICALREACTIONSTHEPHASECHANGEMUSTOCCUREITHERDURINGDROPLETFLIGHTORSOONAFTERIMPACTTHETIMEANDPLACEOFTHISCONVERSIONWILLALSOAFFECTTHEDROPLETSINTERACTIONWITHTHESUBSTRATE30,31ANDTHEFINALDEPOSITIONCREATEDTOFURTHERCOMPLICATETHEM
33、ATTER,DROPSMAYSOLIDIFYNONUNIFORMLY,CREATINGWARPAGEANDOTHERUNDESIRABLERESULTS32INDIRECTPRINTING,ANADDITIONALCHALLENGEARISESTHATOFCONTROLLINGDEPOSITIONATOPLAYERSOFPREVIOUSDEPOSITIONRATHERTHANONLYUPONTHEINITIALSUBSTRATE7,10THEDROPLETSWILLINTERACTDIFFERENTLY,FOREXAMPLE,WITHAMETALPLATESUBSTRATETHANWITHAS
34、URFACEOFPREVIOUSLYPRINTEDWAXDROPLETSTOCREATESUBSTANTIVETHREEDIMENSIONALPARTS,EACHLAYERDEPOSITEDMUSTBEFULLYBOUNDTOTHEPREVIOUSLAYERTOPREVENTDELAMINATION,BUTMUSTNOTDAMAGETHATLAYERWHILEBEINGCREATEDCOMMERCIALLYAVAILABLEMACHINESTENDTOAPPROACHTHISPROBLEMBYEMPLOYINGDEVICESTHATPLANEOROTHERWISESMOOTHTHESURFAC
35、EPERIODICALLY3234OPERATIONALCONSIDERATIONSALSOPOSEACHALLENGEINPROCESSPLANNINGFORPRINTINGFOREXAMPLE,BECAUSENOZZLESARESOSMALL,THEYOFTENCLOG,PREVENTINGDROPLETSFROMEXITINGMUCHATTENTIONHASBEENGIVENTOMONITORINGANDMAINTAININGNOZZLEPERFORMANCEDURINGOPERATION32MOSTMACHINESCURRENTLYINUSEGOTHROUGHPURGEANDCLEAN
36、INGCYCLESDURINGTHEIRBUILDSTOKEEPASMANYNOZZLESOPENASPOSSIBLETHEYMAYALSOWIPETHENOZZLESPERIODICALLY33SOMEMACHINESMAYALSOEMPLOYCOMPLEXSENSINGSYSTEMSTOIDENTIFYANDCOMPENSATEFORMALFUNCTIONINGORINCONSISTENTNOZZLES35,36INADDITION,MANYMACHINES,INCLUDINGALLCOMMERCIALAMMACHINES,HAVEREPLACEABLENOZZLESINCASEOFPER
37、MANENTBLOCKAGEFINALLY,TOACHIEVETHEBESTPRINTRESOLUTION,ITISADVANTAGEOUSTOPRODUCEMANYSMALLDROPLETSVERYCLOSETOGETHERHOWEVER,THISREQUIRESHIGHNOZZLEDENSITYINTHEPRINTHEAD,WHICHISUNATTAINABLEFORMANYNOZZLEMANUFACTURINGPROCESSESANALTERNATIVETONOZZLEDENSITYISTOMAKEMULTIPLEPASSESOVERTHESAMEAREA,EFFECTIVELYUSIN
38、GPROCESSPLANNINGINSTEADOFHARDWARETOCREATETHEDESIREDEFFECT33EVENINCASESWHEREHIGHNOZZLEDENSITYISPOSSIBLE,HOWEVER,PROBLEMSARISEDUETOCROSSTALKBASICALLYAN“OVERLAPPING”OFTHETHERMALORPRESSUREDIFFERENTIALSUSEDTODRIVEADJACENTNOZZLESINAPPROACHINGAPRINTINGPROCESS,THESENUMEROUSCHALLENGESMUSTINSOMESENSEBEADDRESS
39、EDSEQUENTIALLYFLIGHTPATTERNCANNOTBESTUDIEDUNTILDROPLETSAREFORMEDANDLAYERINGCANNOTBEINVESTIGATEDUNTILDEPOSITIONOFSINGLEDROPLETSISCONTROLLEDINTERMSOFFUNCTIONALPOLYMERDEPOSITION,THECHALLENGEOFMATERIALPREPARATIONHASEFFECTIVELYBEENADDRESSEDNUMEROUSPOLYMERRESINSANDMIXTURESALREADYEXISTITISTHESECONDCHALLENG
40、EDROPLETFORMATIONTHATISTHEREFORETHECURRENTLIMITINGFACTORINDEPOSITIONOFTHESEMATERIALSTOUNDERSTANDTHESELIMITATIONS,SECT译文印刷工艺资料来源HTTP/SPRINGERLIBTSINGHUAEDUCN作者IANGIBSON；DAVIDWROSEN人们常对印刷技术进行调查，但历史上被调查的大多数企业都是使用二维印刷技术。现在二维印刷技术已经扩大到许多新的应用领域，包括电子产品包装，光学，和添加剂制造。其中一些应用，其实已经从字面上考虑到一个新的层面的技术。三维打印技术创造就业机会，已迅
41、速成为一个极具潜力的生产实践活动，被广泛的研究和越来越广泛的应用。本章将总结印刷在加工业和制造业取得的成就。在对商业聚合物印刷调查之后，人们对用3D技术制作零件的过程进行了总结。其中介绍了部分直接印刷技术和粘结剂。直接印刷技术是指在所有材料的一部分，免除了打印头，而粘结剂印刷指的是广泛的一类程序，在粘合剂或其他添加剂成批量印刷的。一些介绍技术印刷的书籍说到刷聚合物材料的发展，金属材料的开发，陶瓷印刷是一些细节的技术提供。从纯印刷技术的角度，我们应该更多的注意3D印刷技术。作为一个三维建筑法印刷术，第一次被提及是在20世纪80年代演示相关的弹道粒子制造的一篇文章上。第一个成功的商业应用，是桑德斯
42、在1994年推出的，主要过程是将一个基本的蜡印材料加热到液体状态。MODELMAKER利用合同规定引进的另一蜡基印刷机，在1996年加入了3D系统与之竞争。该合同在1999年进行了修订。2001年，桑德斯国际设计了一种简单制造工具方法，厂商快速进入市场，但很快就因与SOLIDSCAPE知识产权冲突被抑制。值得注意的是，所有的RP型号的印刷热塑性塑料在加入热糯材料后制造的第一代机器，反而最适合铸造概念建模和投资模式。20世纪90年代初，宾德印刷方法在麻省理工学院得到了发展。他们开发的三维印刷的过程，是在一个活页夹上铺上一床粉，然后分成几部分利用截面打印。对比这与SLS，其中激光熔化粉末粒子来定义
43、部分断面的概念。一个重涂系统类似烧结机，然后存款另一个粉层，使机打印粘结剂定义下的横截面，金属和陶瓷材料已广泛以这种方式处理。有几家公司授权来自麻省理工学院的3DP技术开发，并制造成功的机器，包括ZCORP和EX。这次讨论将继续在第二节。最近，印刷技术发展的重点是对丙烯酸酯光敏沉积，液体单体形成液滴，然后暴露在紫外线灯光下，以促进聚合。经光聚合是相似的光固化，但是其他进程的挑战有显着差异。这种对几何与OBJET公司在2000年从以色列抵达机外接市场的第二次浪潮的前沿。两台机器喷出一个感光树脂，1500多喷嘴打印头。2003年，三维系统的推出，其前锋娱乐3D打印机竞争的技术。多射流的造型，在本机
44、打印系统使用，实际上是一个与THERMOJET线开发的技术推广，尽管在物质凝固战略的转变。公司不断创新，这将在下一节讨论。就像业界和研究应用印刷上一节中所讨论的，印刷已经成为了一个成功的调幅技术，具有强大的立足点。但是，仍存在一些阻碍其进一步成长发展的严重技术缺陷。为了识别和解决这些问题，和有关的现象，其发展商采取的战略方针必须理解。在接下来的两节，印刷过程中的技术挑战的概述，它的局限性最相关的功能性聚合物沉积重要的是确定的，以及这些限制是目前需要解决的。由于三维制作印刷是一个极其复杂的过程，具有挑战性的技术问题贯穿，这些挑战，首先是液体的材料配方。如果材料不是液体状的开始，这可能意味着暂停在
45、承运人液体颗粒，溶解在溶剂材料，熔化固体聚合物，或混合的单体制订或与聚合引发剂。在许多情况下，其他物质，如表面活性剂加入到液体达到可以接受的特点。整个行业都致力于为油墨混合二维印刷，它是合理的假设，今后这也将是三维制作的情况。第二关是克服液滴的形成。要使用喷墨沉积的方法，材料必须转换从液体变成离散的小水滴数量连续容积。这个功能通常是在材料之间的依赖关系微调打印，硬件投入，而工艺参数的实现液滴的形成方法的数量是派了讨论。该材料的微小变化，如增加小粒子，可以显着地改变其行为，以及形成液滴，因为可以到物理设置的变化。第三个挑战是对这些液滴沉积控制，这涉及到液滴的飞行路径，影响的问题，与基材润湿或互动
46、。在印刷过程中，无论是打印头或底物通常是移动的，所以对液滴运动轨迹的计算必须考虑到这个问题。除了对液滴的形成，液滴速度和规模也将影响到沉积特征的位置，如教提及。72，必须测量，并通过喷嘴的设计和操作控制。液滴的质量影响也必须加以控制。如果液滴小，称为卫星，打破了由主液滴飞行过程中，则存放材料将在更大范围扩散，沉积比预期不会有差异。以同样的方式，如果对影响液滴飞溅形成所谓的“皇冠“，将出现类似的影响。同时，液滴的液体材料转换为立体几何，必须严格控制，如教讨论。直接打印依赖于对印刷材料的相变。相更改现有印刷技术采用模式的例子有融化的材料（如蜡，焊），在一个解决方案（例如，一些陶瓷凝固的液体部分蒸发
47、办法），固化的感光树脂（如家饰展、计划展机）或其他化学反应。必须发生相变或液滴飞行过程中或之后不久的影响此转换的时间和地点也会影响液滴与基板，最终沉积创建互动。为了进一步把问题复杂化，可能会巩固不均匀下降，造成翘曲和其他不良后果。目前，在直接印刷技术中，又出现了一个额外的挑战关系到以前的沉积层之上，而不是只控制最初的沉积基板。液滴之间的互动有所不同，例如，一个比一个以前打印蜡滴的金属板表面基板。要创建三维实体零件，每一层存放必须完全绑定到上一层，以防止分层，但不得损害该层。市售机倾向于雇用办法或其他设备，飞机表面光滑定期这个问题。运作方面的考虑也构成了对印刷工艺规划中的挑战。例如，由于喷嘴是如此之小，他们经常堵塞，防止退出的飞沫传播。大部分注意力都给予监控和维护操作过程中喷嘴的性能。目前大多数计算机使用中，通过清洗和清洁周期保持开放尽可能多的喷嘴，它们也要定期擦拭喷嘴。有些机器还可以使用复杂的传感系统，以识别和补偿故障或不一致的喷嘴。此外，许多机器，包括所有商业机器，都需要在永久堵塞的情况下更换喷嘴。最后，为了达到最佳的打印分辨率，需要使喷嘴非常接近，然而，这是许多喷嘴制造工艺达不到高密度喷嘴。解决办法是使喷嘴密度提高，在同一区域实现多个传递，有效地利用规划，创造预期的效果。即使在喷嘴密度高的情况下，由于驱动的热或压力差，出现相邻喷嘴“重叠“的问题。
