Sintering And Additive Manufacturing: The New Paradigm For .
http://dx.doi.org/10.1595/205651315X688523Johnson Matthey Technol. Rev., 2015, 59, (3), 233–242JOHNSON MATTHEYTECHNOLOGY REVIEWwww.technology.matthey.comSintering and Additive Manufacturing: The NewParadigm for the Jewellery ManufacturerEuropean jewellery industry poised to develop potential of direct metal lasermelting in precious metalsBy Frank CooperJewellery Industry Innovation Centre, School ofJewellery, Birmingham City University,Birmingham, UKEmail: Frank.Cooper@bcu.ac.ukThe use of various sintering technologies, allied tosuitable powder metallurgy, has long been the subjectof discussion within the global jewellery manufacturingcommunity. This exciting, once theoretical andexperimental technology is now undoubtedly a practicalapplication suitable for the jewellery industry. All partsof the jewellery industry supply and value chains, andespecially design and manufacturing, now need tobecome aware very quickly of just how unsettling anddisruptive this technology introduction has the potentialto become. This paper will offer various viewpoints thatconsider not only the technology and its application tojewellery manufacture but will also consider the newdesign potentials of the technology to the jewelleryindustry. It will also briefly consider how that designpotential is being taught to future generations ofjewellery designers at the Birmingham School ofJewellery. We shall also discuss in some detail theeconomics of and potential for new and differentbusiness models that this technological paradigmmight offer the jewellery industry.233RationaleThis paper intends to explore and open up for debate bythe jewellery industry what actions and understandingmight be required in order to facilitate the transferand acceptance of precious metal direct metal lasermelting (DMLM) technologies and processes into amanufacturing process specifically tailored for thejewellery manufacturing industries and their relatedvalue and supply chains. The goal of the JewelleryIndustry Innovation Centre (JIIC) and its parentinstitution, the Birmingham School of Jewellery, UK, is toencourage its students to develop, design and producecomputer aided design (CAD) examples of jewelleryproducts to challenge, prove, and democratise theprocesses and materials required for the application ofprecious metal DMLM technology into the productionfacilities of small and medium-sized enterprises(SMEs) within the jewellery manufacturing sector.The paper also assesses and attempts to quantify thecurrent perceived industry needs for an adaptable,low-volume and innovative new technology that willfacilitate rapid responses by SMEs to the consumer’sdemands for more custom-made, individually designedand personalised jewellery products. Typical jewellerymanufacturing processes like lost-wax investmentcasting or stamping do not have either the necessaryquick response times or, more importantly, the designand production flexibility required to address these 2015 Johnson Matthey
http://dx.doi.org/10.1595/205651315X688523issues. This paper is intended to help increase industryawareness, knowledge, and especially it is hoped tospeed up jewellery industry uptake of the new designand production capabilities offered by the DMLMprocesses for working with precious metals.The Economic ArgumentThis section will focus primarily on the Europeanjewellery market sector and its financial models.The European Union (EU) has traditionally been animportant supplier of high-quality jewellery to the world’smarkets, and is also considered to be the second orthird largest market for jewellery consumption, afterthe USA (China and India vie for the other placesdepending on the statistical analysis method used).Sales of jewellery in most EU countries are thoughtto have risen steadily in the decade from 2005 to thepresent; however, this volume market is predominantlysupplied with jewellery items manufactured outside theEU. Socio-economic factors mean that it is very difficultfor the European jewellery manufacturing industryto be competitive on price alone. Recent global, andparticularly EU, economic and financial crises havefurther impacted the EU jewellery manufacturingindustry and recent massive price rises in all preciousmetals have somewhat weakened jewellery sales.Consumers seem to have reduced their expenditure onjewellery and sought personalised pieces with greaterassociated personal value (1).High-quality jewellery manufacturing has longbeen an important sector within the EU economy.Detailed information on employment statistics for theEU jewellery industry is difficult to source and defineaccurately but there are thought to be some 30,000smaller companies, with less than 250 employees each,and around 200 larger companies with an estimatedtotal of 180,000 employees. These are companiesthat specialise either in a style of jewellery design orin a stage of production (2). The World Gold Councilhas estimated that in 2014 the global demand for goldjewellery was US 100 billion (3).Within the EU and other developed economies,consumers have been educated by the fast-moving,digital, online revolution to expect a continuous andregularly updated choice of new and innovativeproducts. This has impacted consumer buying patterns,resulting in a surfeit of choice and an ever increasingcompetition for their disposable incomes. It could safelybe predicted that the future high-value jewellery market234Johnson Matthey Technol. Rev., 2015, 59, (3)could well be increasingly driven by a growing demandfor custom-made, personalised, individually designedand innovative designs of high-quality and high-valuejewellery as high precious metal prices have resultedin many consumers now considering the design andinnovation within a jewellery item as equal to if notmore important than its base intrinsic value (4).Increased affluence in the newly emerging economies,coupled with a rising number of marriages, workingwomen, increased shopping opportunities and anonline interest in fashion, are thought to be the maindriving forces behind the latest growth in precious metaljewellery sales in these areas. However, consumersare also more careful with their spending. There is agrowing fatigue towards ‘fast turnover fashions’ andmany consumers now have increasing opportunityto favour good and uniquely personalised ‘statement’designs and regard these as more important than theintrinsic value of a jewellery piece.Global economic uncertainty makes it difficult topredict future jewellery industry trends, but the marketis predicted in some quarters to begin to expand. Inthe near future the EU jewellery market is expectedto grow, especially in the Eastern EU and accessioncountries due in part to their newly emerging middleclasses. It is the contention of the present article thatthe EU market in particular will increasingly demandhigher quality products, coupled with original designsand statement jewellery with added perceived value,personalisation, or new production technologies (5–8).A key question is therefore: “Is there a viableeconomic argument for considering adoption ofDMLM technology?”. The present author believesthat the jewellery manufacturing sector in the EUhas the potential to grow significantly further if newhigh-technology approaches such as DMLM areadopted and exploited effectively. While all materialsused in the production of precious metal jewellery areintrinsically expensive, DMLM offers a technology shiftthat is able to potentially reduce material usage whileoffering new market opportunities.Technology and DesignDMLM was developed during the 1990s in Germany(9). Beginning with CAD data, several layers of metallicpowder are successively deposited one on top of theother. Each layer of powder is heated using a focusedlaser beam corresponding to a selected cross-section ofthe part to be produced. The powder bed is then dropped 2015 Johnson Matthey
tally and another layer of powder is appliedand smoothed by a blade prior to application of the nextpass of the laser beam, simultaneously fusing each newlayer of powder to the layer below it. The method differsfrom the related technique of direct metal laser sintering(DMLS) in that the layer of metallic powder is fully moltenthroughout. The method does not require any binders orfluxing agents. Each run of the laser beam partly overlapsthe preceding run, and a protective gas atmosphere ismaintained above the interaction zone of the laser beamand the metallic powder. Once finished the powder bedis removed from the machine and excess powder isthen removed and can be fully recycled, although somesieving may be required. Figure 1 shows a schematic ofthe process (10).A key opportunity is presented to the EU jewellerymanufacturing sector through the harnessing of theemergent and rapidly maturing DMLM technologiesand processes, which will facilitate the manufacture ofuniquely designed, high-value-added, often custommade, personalised, jewellery products that will beinherently resistant to being copied (11).The initial concept and design phases define theinnovative nature of a jewellery product during theearly stages of its development. The process ofdesign enables the definition and development ofconcepts and ideas and individual personalisation orcustomisation of an item, facilitating commerciallyviable new product development. The transfer of theseJohnson Matthey Technol. Rev., 2015, 59, (3)concepts and ideas into jewellery products is achievedthrough a variety of technical processes includingCAD (12), prototyping and light engineering basedprocesses and technical feasibility is traditionally avital consideration at each stage of the design process.As previously discussed, consumer demand forincreasingly novel products has resulted in the needfor extreme flexibility in the design and production ofjewellery, the ability to respond rapidly to ever changingdemands, and the implementation of a streamlinedproduct development process by manufacturers ofpersonalised and custom-made products, not justjewellery. The UK jewellery industry has a significantglobal reputation for producing well-designed, well-made,high quality jewellery products, manufactured incontrolled and regulated environments that meet thehigh expectations of their end consumers. A radicallynew manufacturing approach could be considered asbeing useful to help re-energise the precious metaljewellery manufacturing base and to help facilitate newopportunities to boost production, increase profitabilityand regain market share. DMLM, which is nowadaysroutinely considered to be part of the rapid or additivemanufacturing (AM) stable of technologies, has nowbecome an accepted production solution within arange of industrial manufacturing sectors includingaerospace, automotive, dental and medical, where AMis used to manufacture parts in a range of ceramic,polymeric and base metallic materials.Tilted mirrorwith focusLaserBurning point(partiallysinteredgranules)ObjectPowderBlade forspreadingpowderPlatform andretractable tablePowder delivery systemBuild spaceFig. 1. Schematic of the DMLM process (10) (Reproduced with the permission of the Verein Deutscher Ingenieure eV,Germany)235 2015 Johnson Matthey
http://dx.doi.org/10.1595/205651315X688523Early research undertaken in Sweden in 2005 (13)and much more recently in the UK (14) and Europehas demonstrated that DMLM technologies could beextended to the manufacture of products in preciousmetals, including 18 carat golds in various colours,silver alloys and even platinum group metals. Thisdiscovery led to some early global interest in the use ofDMLM for precious metal parts manufacture. However,the principal experience of precious metal DMLM todate has been largely limited to the cosmetic dentalindustry, which has adopted some digital productionsolutions in precious metals (15). Additionally, this useof the technology in dentistry was restricted to a smallnumber of specialist gold alloys used for restorativedental crowns in non-jewellery specific alloys. Manypotential alternative uses for precious metal DMLMhave also been identified including electronics, fuel cell,medical, catalytic and satellite applications and in themanufacture of low-volume, high-value components inthe prestige automotive, biomedical and marine sectors(16). There has also been much discussion concerningthe potential for precious metal DMLM and its intrinsicdesign benefits within the jewellery and high-valuegoods sectors, but the research, capital investment,and metallurgical knowledge base required to set upa precious metals DMLM sector have until now beenconsidered largely prohibitive (17).Currently there are a small number of different DMLMtechnologies at various stages of development and usein and around the European jewellery sector. In 2011the JIIC introduced and continues to deliver a teachingmodule specifically about DMLM technologies andtheir adaptation for jewellery design and manufactureto the cohort of the Design for Industry (DFI) studentsJohnson Matthey Technol. Rev., 2015, 59, (3)at the Birmingham School of Jewellery. Figure 2shows just a few examples of their work. Each of themexplores and takes advantage various aspects of thegeometric design freedoms that the DMLM processoffers. These items were produced for the students ina number of different metals by a UK based supplierof a DMLM technology and were built on a ConceptLaser Mlab LaserCUSING by ES Technology Ltd.The JIIC is also currently actively involved with a UKgovernment funded DMLM of precious metals researchscheme called the Precious project, whose missionstatement reads:“To demonstrate the viability of precious metaladditive manufacturing within the UK Jewelleryindustry from design and manufacturing throughto finishing, polishing and retail” (18).This is a two-year project aimed at elevating the currentstate of the art of DMLM AM within the UK preciousmetal jewellery industry.After a piece of jewellery has been designed andbefore it can be manufactured using DMLM a smallnumber of core activities need to take place: Pre-Processing (Preparing pieces formanufacture). This essentially refers to all frontend software-related activities including the designprocess Processing (Manufacturing jewellery items usingDMLM). This refers to the actual manufacturingprocess using DMLM technologies Post-Processing (Manual and automatedfinishing and polishing processes). This refers tothe post-DMLM manufacture processing stages upto the point where an article is ready for sale.Fig. 2. Examples of students’ work from the Birmingham School of Jewellery DFI DMLM module. From left to right: NataliaAntunovity, Suyang Li, Tesni Odonnell, Tomas Binkevic236 2015 Johnson Matthey
http://dx.doi.org/10.1595/205651315X688523Each of these steps is interdependent on the othersand they must take place in a logical sequence. Whencombined together effectively this can result in theproduction of novel and unique quality jewellery items.Understanding these various activity interrelationshipshas a profound effect on the eventual quality of anyDMLM printed jewellery. If a jewellery designerunderstands, even on a fairly superficial level, what isinvolved in each of these core activities then they willbe able to better design jewellery that not only takesadvantage of the geometric freedoms that DMLMoffers but also can be suitably post-processed to anacceptable quality of finish.Johnson Matthey Technol. Rev., 2015, 59, (3)Fig. 4. An example of the CAD created support structures onan OjoCase Study: The Ojo ProjectTo illustrate this a pendant piece from the Preciousproject, called ‘the Ojo’, will be used to show the variousstages of designing and manufacturing jewellery for theDMLM process. The Ojo is intended to be an iterativedesign series of 100 pendants where each pendantproduced is significantly different from the pendantbefore and the pendant after. This is achieved by theuse of a CAD design algorithm that continually morphsthe basic pendant design. This pendant was conceivedand designed by Lionel T. Dean of Future Factories whois a member of the Precious consortium of companies.The CAD file is created, saved as a stereolithography(STL) file and is shown in Figure 3. The next step isto use a suitable software to generate and place thesupport structures (Figure 4) that are a necessarypart of the DMLM process which requires the jewellerydesign to be ‘sliced’ in the software. The parts are builtup of multiples of these slices printed by the DMLMFig. 3. CAD images of the Ojo237technology one on top of the other. Parts being builtusing DMLM require a support structure (19), this is ascaffold-like construction, and supports all overhangingparts enabling undercuts, voids and holes to beproduced. A jewellery designer will not need to beable to create these supports, as they are added bythe DMLM machine setter and the machine’s softwarepackage, but they will need an appreciation of the useand application of supports as they leave a witnessmark or scarring when they have been removed, whichwill require extra cleaning up and finishing (similar tothat required when removing a casting sprue). In theoryit is possible to build any shape, however if supportedareas are visible but inaccessible, then the result willbe perceivably poor surface quality. A small change toa design can eliminate the need for a lot of supportstructures.Support structures are required in most, if not all, laserpowered, metal-based DMLM processes, and thereare a number of divergent reasons for their presence.To build complex geometries with overhanging andundercut surfaces, support structures are requiredto assist in controlling any potential defects in or onthe part being built. These defects may be caused bythe typical thermal stresses of the DMLM process,occasionally by overheating, or most commonly bybeing dragged over and disturbed by the re-coaterblade applying the next layer of powder. Supports aremost principally required because the powder bedsurrounding the very small melt pool created by thelaser is not sufficient to support the liquid metal phasein place. Other functions of supports are the bondingof the part to the build plate and providing a thermallyconductive connection between the part and the build 2015 Johnson Matthey
http://dx.doi.org/10.1595/205651315X688523Johnson Matthey Technol. Rev., 2015, 59, (3)plate to rapidly and effectively dissipate heat from themelt zone.The next step is to fill the machine with powder, loadup the STL file and set it into motion. A re-coater blade,or brush, pushes fine, powdered, gold build materialfrom a carefully measured powder supply hopper tocreate a uniform layer over the build platform. The laserscanning system literally draws the two-dimensional(2D) cross-section of the CAD file slice on the surfaceof the build material, melting it into a solid deposit layeror slice (Figure 5). After the first layer is produced, thepiston beneath the build platform is lowered fractionallyand another powder layer is pushed into place usingthe blade. The laser beam melts the second layerand at the same time fuses or bonds it to the layerbelow. This process is repeated layer by layer until thepart is completed. It is this layer adding process thatleads to this technology being described as ‘additivemanufacturing’ in many quarters.Once the build process has been completed thebuild plate piston is slowly raised, the surplus unusedpowder is carefully swept away and the ‘additivelymanufactured’ jewellery item is exposed (Figure 6).The part is then removed from the build platform andthe support structures are also removed (Figure 7).The witness marks or scarring left by the supports alsohave to be removed in much the same way as a castingsprue has to be removed and cleaned up. Becausethe support structures are much smaller than a typicalsprue, a small, fine, burr on a pendant or Dremmel drillwill often suff
suitable powder metallurgy, has long been the subject of discussion within the global jewellery manufacturing community. This exciting, once theoretical and experimental technology is now undoubtedly a practical application suitable for the jewellery industry. All parts of the jewellery industry supply and value chains, and
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Dr. Sunita Bharatwal** Dr. Pawan Garga*** Abstract Customer satisfaction is derived from thè functionalities and values, a product or Service can provide. The current study aims to segregate thè dimensions of ordine Service quality and gather insights on its impact on web shopping. The trends of purchases have
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This paper tries to present a comparative picture of the different additive manufacturing technologies. Keywords: Additive manufacturing technologies, Comparative study, Direct metal deposition, laminated object manufacturing, Selective laser melting, Selective laser sintering, Stereolithography . (
The solid-state sintering presents the third step in ceramics production. For alumina ceramic, solid-state sintering involves densifying a green body into a dense solid object at a high temperature above 1500-1800 C without melting (the melting point of alumina is 2050 C). Sintering to full density can be achieved at atmospheric pressure .
