Principles Of Additive Manufacturing

Principles Of Additive ManufacturingAdditive manufacturing (AM) is a general term for all technologies that make move by shape addition of temporal at the micron level, to chance upon the unavoidable shape, alike of metallic chemical element removal technique which is traditional subtractive outgrowth. During investigate period, AM the seam by mould manufacturing terminology has been standardised by the Ameri mountain society for testing and substantials (ASTM) committee F42 on additive layer technologies.In the beginning AM technologies were restricted beca purpose of normally accepted leading gens Rapid prototyping (RP) for the piddleion of percentages and prototypes, which was the term enforced for numerous days to describe all layer additive manufacturing mathematical offshootes. Advancement in the sensible, puzzle out and system hardw atomic number 18 cle atomic number 18d that the slices could be manufactured with an equal mechanical plaza to let for fu rther applications. This al milded the proceedsion of end use molds with layer additive technologies, so rapid manufacturing (RM) was adopted which distinguish the working(a) nature of the models produced from the prior RP split and prototypes. upstartly AM is used by and large and RM and RP ar only use to illustrate the particular application of AM technologies.1.2.1 Principles of Additive ManufacturingAM technologies fabricate models by f victimisation, sintering or polymerisation of materials in mold layers with no needs of tools. AM contracts attainable the manufacture of abstruse geometries including internal part detail that atomic number 18 approximately non executable to manufacture using machining and moulding emergencees, because process does not require predetermined tool paths, draft angles and under cuts.In AM the layers of a model atomic number 18 get uped by slicing frankfurter data with headmaster package. All AM system work on the identical re gulation however, layer thickness depend upon parameters and utensil being used and thickness of layer range from 10m up to ccm. beds are clearly visible on the part fold up in AM operation, which keep in lines the quality of final product. The relation between thickness of layer and stand up eastwardation is known as staircase effect. However, refinedner the layer is the longstanding the touch on quantify and amplyer the part resolution. forms in AM are built up at the backsheesh of the previous wizard in z axis of rotation. After layer gets impact the work weapons platform is dropped cumulus by the star layer thickness in z axis and the young material layer is recoated dissimilarly for number of other methods. In rosin found system traversing edge flatten the resin, in grind establishd system deposited powderise is spread using roller or contact weapon system, in some system the material is deposited through a schnozzle which deposits the required materia l. Because recoating time is even longer than the layer bear upon time. For that saki multiple split are haomaing together in the time of mavin material recoating plant. Different batswares are uncommitted to position and orient part so that maximum number of move brush off be built together. Available softwares are VISCAM RP and Smart Space used in MAGICS.Some delicate move produced through AM technologies need a support twist to suckle the part in work platform during the build process. All AM shape uses different support structure that are knowing from specific material for effective use of build parts. Commonly used support structures are thin small pointed dentition to minimising the part contact so that they can be shootd soft with the hand tools.1.3 Rapid PrototypingRapid prototyping processes are a relatively new-fashioned t each(prenominal)ing, accurately draw as layer manufacturing processes. The first commercial RP mold was released at the AUTOFACT sh ow in Detroit (USA) in November 1987 by the comp any named 3D systems. The process begins with creating a 3D model using CAD software and it is identical for all built techniques. The model is hence convert in to Standard Triangulation Language (STL) format, this format shows the 3D rises as an assembly of many planner triangles. At next stage STL file slice the 3D model in to layers. As we know the additive manufacturing is gradual process in which parts are manufactures through layers and each layers are get together and process continues until the final part formed. Post processing is usually required to improve the surface cobblers last of the product.RPs additive nature allows is to create parts with complicated internal features which is not possible by other means like hollow disciplines and undercuts for that these parts sometimes supports are necessary. (palm, W. (1998, May). Rapid Prototyping primer. Retrieved November 4, 2010, from Learing factory Rapid prototyping home page http//www.mne.psu.edu)RP products often have low functionality and commonly used as a visual aids with in product adoptment. However material selection decide the prototype testing for pitiful term functionality parts. Most of the RP materials are polymer based, which is for limited part functionality. Although for little part functionality paper and starch based materials are used. RP modernised the product development with an ability to produce single and multiple fleshly models, facilitating the reduction of product development cycle time ranging for different industries.1.3.1 Rapid prototyping technologiesThere is a huge number of experimental RP technologies either in development or used by small groups of individuals. RP techniques those are currently commercially available includingStereolithography (SLA) is the first RP technique developed by 3D systems in 1987. SLA builds single layer at a time by tracing diffuse of optical maser on the vat of liquid UV cur able pic polymer resin. UV light strikes the surface of the polymer resin and solidify the single layer of resin, when one layer is cured the built platform is dropped down by single layer thickness (Schmitt, Q. L. (2005). Rapid prototyping in dentistry applied science and application. Rapid prototyping in dentistry technology and application , 11-13,42,44). A resin filled blade sweeps over the cross section and fill it with fresh material for further curing at the crystallise of the previous layer, process continues until the model is produced. Material self adhesive property bond each layer and form a masterful 3D model, fabricated part is exculpateded in dawanol resin, alcohol and then cured in a UV oven. (wikipedia. (2010). wikipedia free encyclopedia. Retrieved November 1, 2010, from wikipedia web site http//en.wikipedia.org/wiki/stereolithography)Selective laser sintering (SLS) uses powdered materials. This is one of the systems major advantages that a part could be built in any fusible powdered material. SLS technology was developed in Texas University, which was commercialised in 1993 by company named DTM. In 2001 the DTM were bought out by 3D systems. (http//www.jharper.demon.co.uk/rptc01.htm)This technology works by selectively sintering fine powder materials without delay using an infrared (IR) laser from CAD. Numbers of thermoplastic materials are processed in SLS like nylon (polyamide) for rapid tooling application, aluminium filled nylon, polystyrene for sacrificial pattern in investment casting and gas filled nylon. cave in produced through this process used as functional model as well as visual prototypes because of good mechanical properties.However as compared to traditional tool steel the part had poor mechanical properties, so material required post processing to form dense models, olibanum it was very difficult to operate on the part the true because of introduced stresses in processing stage. With the combination of EOS GmbH and Electrolux a special alloy powder was developed, which did not develop shrinkage distortions. Moreover admittance of fibre laser technology allowed the introduction of Selective laser dissolve (SLM) since the fibre laser allowed the sintering of metals that were completely go away in to dense part with no need of post process infiltration.Numbers of other technologies have been commercialised since 1991 such(prenominal) as laminated aspiration manufacturing (LOM), fused deposition modelling (FDM), 3 dimensional printing (3DP). Recent technological availability of RP is increased with material diversity, which increased the efficiency of creating somatogenic prototype in advanced product development.1.4 Definition of Rapid ManufacturingFirstly, it is congenital to give a definition of rapid manufacturing. The way that several parts are manufactured will miscellany in the future. RM has been explained as the use of a CAD-based automated AM process to construct parts that a re used directly as finished products or components (Hopkinson et al. 2006, p. 1)Since with the time change, the investigate on AM technologies and materials has advanced and the feasibility of fabrication of functional, low brashness parts are increasingly in many industries. Many industries are examining the available technology and investigating the possibilities of design to increase the broad(prenominal) functional component and to reduce product to market time. A key emolument of RM approach claimed that it proposes the opportunity of mass customization, however can be bell effective for individual short run part, clearing conventional conniving constraints of manufacturing processes. RM greatly minimised wastage of raw material as compared to subtractive process, so got democratic in aero quadruplet industry, where expensive metal alloys are extensively used. The label material such as te, ABS, nylon and aluminium has been the important part in the give of RM technolo gies.(http//www.hse.gov.uk/horizons/rapidmanufacturing.pdf)The introduction of RM is not as simple as it first appears, although research in RM technologies and application are progressed by RP. The evolution is still in progress to link RM from research to actual manufacturing for that number of matters to be scrap to that prevail need explanation and consensus before it can happen. RP produced prototype were not considered for product repeatability and quality measures. Since products of RM have proposed functionality, industrial certification and the requirements include material control, accuracy, stop number, surface finish and part repeatability, so that RM is success richly applied in many industries including aesculapian, automotive and aerospace to produce low quantity of small, gamy grade parts with Gordian geometries that is difficult through conventional methods.(http//www.rm-platform.com/index2.php?option=com_docmantask=doc_viewgid=129Itemid=5)In future, RM techn ology addition in industries can offer small complex design feature parts that ever imagined with great manufacturing facilities and the extension of approach. suppuration of advanced materials and equipment enable the fabrication of complex product by directly manipulating the matters on a molecular scale.1.5 Selective laser melting (SLM)1.5.1 SLM groundSelective laser melting machine was first introduced by Fockele and Schwarze (FS) of Germany in 1999 with the support of Fraunhofer institute of laser technology that was steel powder based SLM machine. Later in 2004 first SLM machine named Realizer 250 SLM was released commercially after FS coped up with MTT (MCP tooling technologies) and in 2005 high resolution machine named SLM Realizer ampere-second was released.Since the release of the MCP Realizer SLM, other manufacturer such as excogitation laser and EOS released machine with different process named Laser curing and Direct metal laser sintering respectively. C at one time pt laser (GmbH) first released M3 Liner and M1 Cusing in 2001, later they released another machine named M2 Cusing to produce reactive materials like te and aluminium alloys. EOS released the machine named EOSINT M 270 DMLS in 2003 and termed as the most common machine for direct metal fabrication. In 2008 MTT and 3D systems proclaimed a distribution agreement for the rights to carry on SLM machines in Americas and Japan. In 2008-09 new version of SLM was released by MTT named SLM 250 and SLM 125.1.5.2 Basic principles of SLMSLM is a powder based additive manufacturing process that take into accounts attaining 3D functional parts from a CAD data. SLM follows the same process route as SLS, where complete melting of powder occurs instead of sintering or partial melting. run begins with the deposition of thin layer of powder thickness ranging from 50m to 75m across a substrate platform. A high berth fibre laser scans the powder surface, the generated commove melt the powder particl es and form molten pool. Once the layer has been scanned, the platform drops down by single layer thickness in z axis and the fresh layer of powder is deposited and the process is repeated until the entire built is completed. Loose powders are involved once the fully dense part is complete. SLM parts must be completed in inert gas atmosphere such as argon to remove oxygen from the building chamber. Supports like thin teeth shaped are needed to secure hanging features collectable to shrinkage of material solidification. The substrate is removed from the build chamber once the process gets complete and supports are removed carefully.SLM termed as the most viable techniques for direct fabrication of complex featured part of metals. SLM can permit the design optimization and employment of the complex functionalities beyond the capabilities of traditional techniques, which is possible because of accuracy, versatility and the laser beam spot sizing of it. The small laser spot size m inimizes the area to be melt enabling the manufacturing the part of high resolution. However, to be positioned SLM in RM category as a general method to achieve greater recognition in companies, methods and development need to be changed to run and prove itself as being reliable, repeatable and damage effective production process.SLM also known as freeform fabrication process and capable to build thin fence in complex features models of high resolution and extends its capabilities than the conventional processes such as customised medical exam implant especially dental height and pair frame work, tooling inserts with conformal cooling channel and functional models.SLM concerns primarily turn about the application of high powered fibre laser to generate high temperature to completely melt the powder, surface roughness is the main concerns of SLM because of high heat input causes material vaporisation and generation of spatter that subjected by melting and re-solidifying. But S LM parts cover committed microstructure parts and material properties that make possible this technique for the application.Benefits of SLMParts produced in this process are well 100% dense and have same mechanical effectiveness as the original materialAlmost no powder material is wasted, the emancipate powders which was not solidified can be reusedSLM offers minimum time to market, remove shape generation without an expansive moulds, process flexibility and great function of materialSLM powder bed technology permits cheap and fast powder metallurgy. The alloys to be tested can utilized straightly with in the prototyping apparatus and alloys can easily accustomed with the change of elemental ratio of powdersDrawbacks of SLMSLM is regarded as the high temperature gradient, which causes thermal stress build up and rapid solidification so coarse to grainy surface finished parts are producedThe short-staffed availability of some materials in powder form restricts the range of mate rial for processing. Process should be optimised for available material(Selective laser melting, 10 celestial latitude http//raproto.com/?cat=31, accessed on 25/5/2011 and http//www.mtm.kuleuven.be/Onderzoek/a2p2/researchtopics/SLM, accessed on 26/5/2011)1.5.3 SLM materialsSLM technology worked with all possibly relevant metals for part production. Process starts with identifying the physical behaviour of material being used with microscopic level of process understanding. In order to develop technique, the main quality aspect of parts being produced includes surface roughness, high functional strength, accuracy, density, hardness, residual stresses have to be observed before applied for the industrial applications. SLM system always develops parts with variety of materials and new ranges in which material property is easily changed with the property requirement with changing the mixture ratio. The range of materials are used that better the new work powders such as tool steel, inn oxious steel, titanium alloy, aluminium alloy, atomic number 27 chrome and inconel.(http//www.mtt-group.com/data/pdf/extract/0413-MTT_2pp_SLM_A4_%20Flyer_v1.pdf)Materials are described below according to property, alloy and applications(http//www.xyzinnovation.com.au/as pocks/slm-brochure_290709.pdf)TitaniumMechanical properties luxuriously strength, low thermal expansion, high wearing away resistance, excellent machinability and bio compatibility and low weight.Alloys Pure titanium, Ti-6Al-7Nb and Ti-6Al-4VApplications medical implants, jewellery and design, F1 motor sport and aerospaceCobalt chromeMechanical properties risque strength, excellent corrosion resistance and bio compatibility and high toughnessAlloy CoCr ASTM F75Applications medical implant, dental and high temperatureStainless steel, tool steelMechanical properties High toughness, hardness and corrosion resistance and excellent machinabilityAlloys 316L stainless steel, H13 tool steel, 17-4PH, 50CrMo4, CrNiMo 13-4 and M333Applications medical implants, spindle and screws, plastic injection moulds and maritimeAluminiumMechanical properties slender alloying properties and processability and low densityAlloys Al-Si-10Mg, Al-Si-12Mg, Al-Si9-Cu3, Al-Si-7Mg and Al-Mg4Applications Aerospace, automotive, consumer goodsInconelMechanical properties Good mechanical strength, excellent corrosion resistance, outstanding welding ability and good creep rapture strength up to 700CAlloys Inconel 718 and Inconel 625Applications Aerospace, gas turbines, space shuttle and crafts, nuclear reactors and rocket motors integrating of SLM in production systemsProcess compassFunction SLM process chain PartFinish(Machining)Part DesignProcessStrategyProcess take careProcessPreperationDesigned for optimized Part orientation built scheme online defect Interface forFunctionality (quality/ build time) -built parameters detention machining(light, weight, -support structure -under cuts etc -close loop controlenergy efficien t etc )(www.materialscluster.lu/ subject/download//Wilhelm_Intermat2011.pdf, accessed on 30/5/2011)SLM machinesSLM50 RealizerWorlds first SLM desktop machine to produce quickly and extremely accurately manufacture functional dental parts based on CAD data. It is well appropriate for dental laboratories and similar environments for the production of bridge and crown frame and brackets. This machine is capable to produce 100 parts/ months. SLM50 designed a component with height up to 40mm and diameter up to 60mm.(http//www.industrialnews.org/2011/03/worlds-first-slm-desktop-machine-dental.htmlixzz1NtOkViL9)SLM50 specifications face intensity level computer programme diameter 70 mm, max. construction height 40 mmThickness of layers 20-50 mLaser type Fibre laser 20 to 120 W strength supply 16A, 230VPower aspiration 1.0 KW atomic number 18 consumption approx. 30 Liter/hDimensions W800 x D700 x H500 mm cargo approx. 80 kg software package ReaLizer Control SoftwareMaterials Cobalt Chrom e, Stainless Steel 316 L,gold-, silver-, palladium-, titanium alloys(http//www.progold.com/GB/Files/Realizer.pdf)httphttps://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8TFTHrag-BWUD1LSc-oueAf3QW-uju4XMGTUCxmhUqGj6_LQySvxGzhZeRM3FE0yvbPfv_8eYyyGgfe5SSicg7SZlc3lO3CyDxXgfMI5zGsBPJfeO3WRM2lgVZ5dKr9CGB9m-CPSQOOdH/s1600/SLM-50-1024682.jpg(http//www.industrialnews.org/2011/03/worlds-first-slm-desktop-machine-dental.html)SLM100 RealizerMachines dexterity to design a component with 100mm high cylindrical construction area with 125mm diameter, because of the dropped laser spot size to 20m. The machine can produce parts with delicate features, high surface quality and maximum wall thickness. SLM100 is appropriate for dental laboratories or related environments.SLM100 specificationsConstruction volume Platform diam. 125 mm Max. overall constr. height 100 mmLayer thicknesses 20-100 mLaser type Fibre laser 20 to 200 WPower supply 16A, 400VPower input 1.5 kWArgon consumption app. 35 l/hDimensions W900 x D800 x H2400 mm, SLM100A supernumerary display support armWeight 500 kgSoftware ReaLizer control softwareMaterials Tool steel H 13, titanium, titanium V4,aluminium, cobalt chrome, stainless steel 316 L,Inconel, Gold, ceramic materials under development(http//www.realizer.com/en/wp-content/themes/realizer/ReaLizer.pdf)(http//www.twi.co.uk/content/laser_slm.html)SLM125The SLM125 machine presented with a range of laser from 100-200W with 30mm laser spot size diameter. This machine is capable to built pattern geometries of 200m. Surface finish is controlled by laser scan approach, however build speed and surface finish is majorly depends on material that to be processed such as tool steel take more time than the aluminium and titanium. For fully dense part the twain parameters surface finish and build speed should range from 15-30m and 5-200cm3/hr respectively.(http//www.sme.org/cgi-bin/ set-articles.pl?ME09ART20ME20090401SME)This machine has been designed for the simplicity to the users with in a industry with touch screen features, which cleans down the process. Robustness of the machine has give n precedence to the adopters. The recoater blade used in this system is soft and carefully designed to reduce consumable cost by rotating same blade many times before replacement, and low filter element causes low gas consumption, results machine reliable and minimum in cost to users.SLM125 specificationsConstruction volume 125mm x 125mm x 125mm (x,y,z)Layer thicknesses 20 to 100mLaser type Fibre laser 100-200 WPower supply 16A, 400VPower inputArgon consumptionmDimensionsWeightSoftware ReaLizer control softwareMaterials Tool steel H13, titanium , titanium V4, aluminium,cobalt chrome, stainless steel 316 L, Inconel(http//www.mtt-group.com/data/pdf/extract/0413-MTT_2pp_SLM_A4_%20Flyer_v1.pdf)MTT SLM25(http//develop3d.com/profiles/box-clever)SLM250This machine measures construction area of 250-250-250mm. The space in the processing area can be used to produce maximum number of parts with loading numerous parts at the top of each other. SLM250 is equipped with high power laser up to 400 W with an automated filter machine to remove and recycle loose powders from the processing area. High part output makes it appropriate for industrial manufacturing process.SLM250 specificationsConstruction volume 250 x 250 mm , maximum construction height 220 mmLayer thicknesses 20-100 mLaser type Fibre laser 100, 200 or 400 WPower supply 16 A, 400 VPower input 2.5 kWArgon consumption app. 70 litres/hDimensions W1800 x D1000 x H2200 mm w/o sieving machineWeight 800 kgSoftware ReaLizer control softwareMaterials Tool steel H13, titanium , titanium V4, aluminium,cobalt chrome, stainless steel 316 L, Inconel(http//www.realizer.com/en/wp-content/themes/realizer/ReaLizer.pdf)http//www.renishaw.com/media/img/gen/8a0166f5acc64a4190c81957ffe11b05.jpg(http//www.renishaw.com/en/renishaw-acquires-mtt-investments-limited14897)D1 (http//doc.utwente.nl/52914/1/Wa1025.pdf)D2 (http//pic.sagepub.com/content/220/6/857.full.pdf)D3 (http//www.meditech.cf.ac.uk/pages/Individula%20Meetings/15th%20Nov%2020 07/presentations/R%20Bibb%20-%20PDR%20-%20ARUP%20Nov%202007.pdf)SLM 125 machine runSLM 125 machine operated in the following mannerTurn on from the back- MTT 125 screen showed up- tilt on the screen- Login with the user name MTT2- rap light (light fall ins)- Tap to open the room access- hold reset and open the doorWiper reset Tap to wiper and elevator on the screen- stick wiper home- implore to substrate and set thickness to 0- press Esc- hold reset and open the door. Tap to wiper and elevator- recollect wiper home- Go to FWD POS- then unscrew the wiper arm from both endsTo draw material holder or wiper tension unscrew both the mild placed at the ends with pressing at the top. Attach back both the wiper tension and wiper arm to their respective positions- shut the doorBefore placing the platform in the machine , first measure the base plate with vernier calliper then Tap to wiper and elevator- find wiper home- tap at substrate and set the thickness to 14.5- tap at table aut o (it will built)- Tap at set datum- find table home. Go again- substrate set to 0- Go to top POS- Tap at Go to Centre to position wiper at the centreCUsersP10507465DesktopWiper_tension1.JPGLift wiper and place paper then wealthy it. Clockwise rotation of screw to loose and anticlockwise to tight it. Later paper is removed. Just ensure that you should put the same shove during screwing. After setting the wiper arm at the paper canvass thickness- close the door- tap to wiper and elevator- find wiper homeTo clean filter assembly Remove both caping placed at the top and bottom and do not forget to remove the rings- unbolt the holder- remove the filter (twist and draw)- clean the chamber- push filter to attach- bolt itCUsersP10507465DesktopFilter_Assy.JPGCUsersP10507465DesktopFilter_removal.JPGTap to wiper and elevator- find wiper home- set datum- Dose to 3- Go to FWD POS- open with holding reset button. Close the door- find wiper home- Esc- select- auto (safe change filter valve- ye s)- auto operation starts- click ok- Isolate change filter- confirm. execution or part building starts and it logged out automatically after coating the operationLogin again with user name MTT2- tap to wiper and elevator- find wiper home- Go to up- Esc- open the doorCleaning Slowly remove the powder with the purify- later hover it to clean properly. unscrew the base plate- sweep again not to waste powder. Close the door- wiper elevator- find wiper home- Go to FWD POS- Esc- open the door holding reset buttonUnscrew the wiper plate and clean- the red strip on the wiper arm turns black at worked portion means damaged. Unscrew material holder- brush the machine to restore loose powder to the holes (for titanium cleaning is in reality important)Over flow cleaning Unscrew loose powder holder underneath the platform. Put screw at close position and turn around to unscrew it to recover loose powders- screw it and place it in desired place including rings and capingSet wiper back at the position to clean lense- unscrew it and clean it with proper handling dental suprastructureThe manufacturer is also is involved in the dental industry, for which the company manufactures products such as implant-supported suprastructures. Using patient-specific geometry data, acquired through medical imaging or three-D scanning, the personalised structure is designed in software and printed in titanium. As a concluding step, the dental technician finishes off the structure and completes the final prothesis. through patented DentWise technology, geometry and surface retention related limitations set by traditionally moulded or milled suprastructures no longer apply.Through digital SLM technology, geometry and surface retention related limitations set by traditionally moulded or milled suprastructures no longer apply, Mercelis says. In addition, the implant connections are completed with high precision. Implant bars and bridges achieve a fit accuracy better than 20 m at the implant interface. They also can integrate complex surface textures and sealing edges. DentWise suprastructures are manufactured using ultra-strong titanium alloy (Ti6Al4V, grade V), which outperforms the commonly used titanium grade II in terms of mechanical propertie(http//www.emdt.co.uk/article/selective-laser-melting)