WIXLIB

History of 3D Printingdevelopments taking place inapplications across thethe Eastern hemisphere.aerospace, automotive,However, these technologies,medical and fine jewellerywhile significant in themselvessectors, as years of R&D andand enjoying some localqualification are now payingsuccess, did not really impactoff. A great deal still remainsthe global market at that time.behind closed doors and/or!under non-disclosureDuring the mid noughties, theagreements (NDA). At the othersector started to show signs ofend of the spectrum, some ofdistinct diversification with twothe 3D printing systemspecific areas of emphasis thatmanufacturers wereare much more clearly defineddeveloping and advancingtoday. First, there was the high‘concept modellers’, as theyend of 3D printing, still verywere called at the time.expensive systems, which wereSpecifically, these were 3Dgeared towards partprinters that kept the focus onproduction for high value,improving concepthighly engineered, complexdevelopment and functionalparts. This is still ongoing —prototyping, that were beingand growing — but the resultsdeveloped specifically as office-are only now really starting toand user-friendly, cost-effectivebecome visible in productionsystems. The prelude to!153dprintingindustry.com

History of 3D Printingtoday’s desktop machines.influences. The holy grail atHowever, these systems werethat time was to get a 3Dall still very much for industrialprinter under 5000 — thisapplications.was seen by many industry!insiders, users andLooking back, this was reallycommentators as the key tothe calm before the storm.opening up 3D printing!technology to a much widerAt the lower end of the marketaudience. For much of that— the 3D printers that todayyear, the arrival of the highly-are seen as being in the midanticipated Desktop Factory —range — a price war emergedwhich many predicted wouldtogether with incrementalbe the fulfillment of that holyimprovements in printinggrail — was heralded as theaccuracy, speed and materials.one to watch. It came to!nothing as the organizationIn 2007, the market saw thefaltered in the run up tofirst system under 10,000production. Desktop Factoryfrom 3D Systems, but thisand its leader, Cathy Lewis,never quite hit the mark that itwere acquired, along with thewas supposed to. This wasIP, by 3D Systems in 2008 andpartly due to the system itself,all but vanished. As it turnedbut also other marketout though, 2007 was actually!163dprintingindustry.com

History of 3D Printingthe year that did mark theBut it wasn’t until January 2009turning point for accessible 3Dthat the first commerciallyprinting technology — evenavailable 3D printer – in kitthough few realized it at theform and based on the RepRaptime — as the RepRapconcept – was offered for sale.phenomenon took root. DrThis was the BfB RapMan 3DBowyer conceived the RepRapprinter. Closely followed byconcept of an open source,Makerbot Industries in Aprilself-replicating 3D printer asthe same year, the founders ofearly as 2004, and the seedwhich were heavily involved inwas germinated in thethe development of RepRapfollowing years with someuntil they departed from theheavy slog from his team atOpen Source philosophyBath, most notably Vik Oliverfollowing extensive investment.and Rhys Jones, whoSince 2009, a host of similardeveloped the concept throughdeposition printers haveto working prototypes of a 3Demerged with marginal uniqueprinter using the depositionselling points (USPs) and theyprocess. 2007 was the year thecontinue to do so. Theshoots started to showinteresting dichotomy here isthrough and this embryonic,hat, while the RepRapopen source 3D printingphenomenon has given rise tomovement started to gaina whole new sector ofvisibility.commercial, entry-level 3D!173dprintingindustry.com

History of 3D Printingprinters, the ethos of thein awareness and uptakeRepRap community is all aboutacross a growing makerOpen Source developments formovement, 2012 was also the3D printing and keepingyear that many differentcommercialization at bay.mainstream media channels!picked up on the technology.2012 was the year that2013 was a year of significantalternative 3D printinggrowth and consolidation. Oneprocesses were introduced atof the most notable moves wasthe entry level of the market.the acquisition of Makerbot byThe B9Creator (utilising DLPStratasys.technology) came first in June,!followed by the Form 1Heralded as the 2nd, 3rd and,(utilising stereolithography) insometimes even, 4th IndustrialDecember. Both wereRevolution by some, whatlaunched via the funding sitecannot be denied is the impactKickstarter — and boththat 3D printing is having onenjoyed huge success.the industrial sector and the!huge potential that 3D printingAs a result of the marketis demonstrating for the futuredivergence, significantof consumers. What shape thatadvances at the industrial levelpotential will take is stillwith capabilities andunfolding before us.applications, dramatic increase!183dprintingindustry.com

CHAPTER3D Printing Technology!19

3D Printing TechnologyThe starting point for any 3Dceramics and sand are, now, allprinting process is a 3D digitalroutinely used for industrialmodel, which can be createdprototyping and productionusing a variety of 3D softwareapplications. Research is alsoprogrammes — in industry thisbeing conducted for 3Dis 3D CAD, for Makers andprinting bio materials andConsumers there are simpler,different types of food.more accessible programmesGenerally speaking though, atavailable — or scanned with athe entry level of the market,3D scanner. The model is thenmaterials are much more‘sliced’ into layers, therebylimited. Plastic is currently theconverting the design into a fileonly widely used material —readable by the 3D printer. Theusually ABS or PLA, but therematerial processed by the 3Dare a growing number ofprinter is then layeredalternatives, including Nylon.according to the design andThere is also a growing numberthe process. As stated, thereof entry level machines thatare a number of different typeshave been adapted forof 3D printing technologies,foodstuffs, such as sugar andwhich process differentchocolate.materials in different ways tocreate the final object.Functional plastics, metals,!203dprintingindustry.com

How it WorksThe different types of 3Dprinters each employ adifferent technology thatprocesses different materialsin different ways. It isimportant to understand thatone of the most basiclimitations of 3D printing — interms of materials andStart with a 3D CAD file eitherby creating the 3D model orscanned with a 3D scannerapplications — is that there isno ‘one solution fits all’. Forexample some 3D printersprinting process, reminiscentprocess powdered materialsof 2D inkjet printing, but with(nylon, plastic, ceramic, metal),superior materials to ink and awhich utilize a light/heatbinder to fix the layers.source to sinter/melt/fusePerhaps the most commonlayers of the powder togetherand easily recognized processin the defined shape. Othersis deposition, and this is theprocess polymer resinprocess employed by thematerials and again utilize amajority of entry-level 3Dlight/laser to solidify the resinprinters. This process extrudesin ultra thin layers. Jetting ofplastics, commonly PLA or ABS,fine droplets is another 3D!213dprintingindustry.com

How it Worksnegating the need forassembly.!However, another importantpoint to stress is that none ofthe 3D printing processescome as plug and play optionsas of today. There are manysteps prior to pressing printand more once the part comesLayer by layer the printer willcreate the predeterminedshapeoff the printer — these areoften overlooked. Apart fromthe realities of designing for 3Din filament form through aprinting, which can beheated extruder to form layersdemanding, file preparationand create the predeterminedand conversion can also proveshape.time-consuming and!complicated, particularly forBecause parts can be printedparts that demand intricatedirectly, it is possible tosupports during the buildproduce very detailed andprocess. However there areintricate objects, often withcontinual updates andfunctionality built in andupgrades of software for these!223dprintingindustry.com

How it Worksfunctions and the situation is improving. Furthermore, once offthe printer, many parts will need to undergo finishing operations.Support removal is an obvious one for processes that demandsupport, but others include sanding, lacquer, paint or other typesof traditional finishing touches, which all typically need to be doneby hand and require skill and/or time and patience.You will soon start to seethe object become morerecognizableAt the end of the printprocess you will have yourfinalized object!233dprintingindustry.com

CHAPTER3D Printing Processes!24

StereolithographyStereolithography (SL) is widely recognized as the first 3D printingprocess; it was certainly the first to be commercialised. SL is alaser-based process that works with photopolymer resins, thatreact with the laser and cure to form a solid in a very precise wayto produce very accurate parts. It is a complex process, but simplyput, the photopolymer resin is held in a vat with a movableplatform inside. A laser beam is directed in the X-Y axes across thesurface of the resin according to the 3D data supplied to themachine (the .stl file), whereby the resin hardens precisely wherethe laser hits the surface. Once the layer is completed, theplatform within the vat drops down by a fraction (in the Z axis)and the subsequent layer is traced out by the laser. Thiscontinues until the entire object is completed and the platformcan be raised out of the vat for removal.!253dprintingindustry.com

StereolithographyBecause of the nature of the SL process, it requires supportstructures for some parts, specifically those with overhangs orundercuts. These structures need to be manually removed.!In terms of other post processing steps, many objects 3D printedusing SL need to be cleaned and cured. Curing involves subjectingthe part to intense light in an oven-like machine to fully hardenthe resin.!Stereolithography is generally accepted as being one of the mostaccurate 3D printing processes with excellent surface finish.However limiting factors include the post-processing stepsrequired and the stability of the materials over time, which canbecome more brittle.!263dprintingindustry.com

DLPDLP — or digital light processing — is a similar process tostereolithography in that it is a 3D printing process that workswith photopolymers. The major difference is the light source. DLPuses a more conventional light source, such as an arc lamp, with aliquid crystal display panel or a deformable mirror device (DMD),which is applied to the entire surface of the vat of photopolymerresin in a single pass, generally making it faster than SL.!Also like SL, DLP produces highly accurate parts with excellentresolution, but its similarities also include the same requirementsfor support structures and post-curing. However, one advantageof DLP over SL is that only a shallow vat of resin is required tofacilitate the process, which generally results in less waste andlower running costs.!273dprintingindustry.com

Laser Sintering / Laser MeltingLaser sintering and laser melting are interchangeable terms thatrefer to a laser based 3D printing process that works withpowdered materials. The laser is traced across a powder bed oftightly compacted powdered material, according to the 3D datafed to the machine, in the X-Y axes. As the laser interacts with thesurface of the powdered material it sinters, or fuses, the particlesto each other forming a solid. As each layer is completed thepowder bed drops incrementally and a roller smoothes thepowder over the surface of the bed prior to the next pass of thelaser for the subsequent layer to be formed and fused with theprevious layer.!283dprintingindustry.com

Laser Sintering / Laser MeltingThe build chamber is completely sealed as it is necessary tomaintain a precise temperature during the process specific to themelting point of the powdered material of choice. Once finished,the entire powder bed is removed from the machine and theexcess powder can be removed to leave the ‘printed’ parts. One ofthe key advantages of this process is that the powder bed servesas an in-process support structure for overhangs and undercuts,and therefore complex shapes that could not be manufactured inany other way are possible with this process.!However, on the downside, because of the high temperaturesrequired for laser sintering, cooling times can be considerable.Furthermore, porosity has been an historical issue with thisprocess, and while there have been significant improvementstowards fully dense parts, some applications still necessitateinfiltration with another material to improve mechanicalcharacteristics.!Laser sintering can process plastic and metal materials, althoughmetal sintering does require a much higher powered laser andhigher in-process temperatures. Parts produced with this processare much stronger than with SL or DLP, although generally thesurface finish and accuracy is not as good.!293dprintingindustry.com

Extrusion / FDM / FFF3D printing utilizing the extrusion of thermoplastic material iseasily the most common — and recognizable — 3DP process. Themost popular name for the process is Fused Deposition Modelling(FDM), due to its longevity, however this is a trade name,registered by Stratasys, the company that originally developed it.Stratasys’ FDM technology has been around since the early 1990’sand today is an industrial grade 3D printing process. However, theproliferation of entry-level 3D printers that have emerged since2009 largely utilize a similar process, generally referred to asFreeform Fabrication (FFF), but in a more basic form due topatents still held by Stratasys. The earliest RepRap machines andall subsequent evolutions — open source and commercial —!303dprintingindustry.com

Extrusion / FDM / FFFemploy extrusion methodology. However, following Stratasys’patent infringement filing against Afinia there is a question markover how the entry-level end of the market will develop now, withall of the machines potentially in Stratasys’ firing line for patentinfringements.!The process works by melting plastic filament that is deposited,via a heated extruder, a layer at a time, onto a build platformaccording to the 3D data supplied to the printer. Each layerhardens as it is deposited and bonds to the previous layer.!Stratasys has developed a range of proprietary industrial gradematerials for its FDM process that are suitable for someproduction applications. At the entry-level end of the market,materials are more limited, but the range is growing. The mostcommon materials for entry-level FFF 3D printers are ABS andPLA.!The FDM/FFF processes require support structures for anyapplications with overhanging geometries. For FDM, this entails asecond, water-soluble material, which allows support structuresto be relatively easily washed away, once the print is complete.Alternatively, breakaway support materials are also possible,which can be removed by manually snapping them off the part.!313dprintingindustry.com

Extrusion / FDM / FFFSupport structures, or lack thereof, have generally been alimitation of the entry level FFF 3D printers. However, as thesystems have evolved and improved to incorporate dual extrusionheads, it has become less of an issue.!In terms of models produced, the FDM process from Stratasys isan accurate and reliable process that is relatively office/studiofriendly, although extensive post-processing can be required. Atthe entry-level, as would be expected, the FFF process producesmuch less accurate models, but things are constantly improving.!The process can be slow for some part geometries and layer-tolayer adhesion can be a problem, resulting in parts that are notwatertight. Again, post-processing using Acetone can resolvethese issues.!323dprintingindustry.com

Inkjet: Binder JettingThere are two 3D printing process that utilize a jetting technique.!!!!!!!!!!Binder jetting: where the material being jetted is a binder, and isselectively sprayed into a powder bed of the part material to fuseit a layer at a time to create/print the required part. As is the casewith other powder bed systems, once a layer is completed, thepowder bed drops incrementally and a roller or blade smoothesthe powder over the surface of the bed, prior to the next pass ofthe jet heads, with the binder for the subsequent layer to beformed and fused with the previous layer.!333dprintingindustry.com

Inkjet: Binder JettingAdvantages of this process, like with SLS, include the fact that theneed for supports is negated because the powder bed itselfprovides this functionality. Furthermore, a range of differentmaterials can be used, including ceramics and food. A furtherdistinctive advantage of the process is the ability to easily add afull colour palette which can be added to the binder.!The parts resulting directly from the machine, however, are not asstrong as with the sintering process and require post-processingto ensure durability.!343dprintingindustry.com

Inkjet: Material JettingMaterial jetting: a 3D printing process whereby the actual buildmaterials (in liquid or molten state) are selectively jetted throughmultiple jet heads (with others simultaneously jetting supportmaterials). However, the materials tend to be liquidphotopolymers, which are cured with a pass of UV light as eachlayer is deposited.!The nature of this product allows for the simultaneous depositionof a range of materials, which means that a single part can beproduced from multiple materials with different characteristicsand properties. Material jetting is a very precise 3D printingmethod, producing accurate parts with a very smooth finish.!353dprintingindustry.com

Selective Deposition Lamination (SDL)SDL is a proprietary 3D printing process developed andmanufactured by Mcor Technologies. There is a temptation tocompare this process with the Laminated Object Manufacturing(LOM) process developed by Helisys in the 1990’s due tosimilarities in layering and shaping paper to form the final part.However, that is where any similarity ends.!The SDL 3D printing process builds parts layer by layer usingstandard copier paper. Each new layer is fixed to the previouslayer using an adhesive, which is applied selectively according tothe 3D data supplied to the machine. This means that a muchhigher density of adhes

Jul 03, 2014 · Welcome to 3DPI’s Beginner’s Guide to 3D Printing. Whether you are new to 3D printing technology or just looking