Introduction to Metal Additive Manufacturing PDF

EL PT N Dr. J. Ramkumar and Dr. Amandeep Singh Department of Mechanical Engineering and Design IIT Kanpur ▪ This course is for students with engineering backgrounds – both Undergraduate and Postgraduate levels. ▪ Over the next lectures, we will understa...

EL PT N Dr. J. Ramkumar and Dr. Amandeep Singh Department of Mechanical Engineering and Design IIT Kanpur ▪ This course is for students with engineering backgrounds – both Undergraduate and Postgraduate levels. ▪ Over the next lectures, we will understand the additive EL manufacturing process step by step, in detail. ▪ We will talk about various technologies used to carry out these. PT ▪ You should be able to conceive, develop, and 3D print your own designs at the end of this course. N Who can attend this course: The course is not only for engineers or technical people, anyone having an interest or passion for new product development is welcome. ▪ Need of the course EL ▪ Manufacturing Systems ▪ Subtractive Manufacturing PT ▪ Need for Additive Manufacturing ▪ Introduction to Additive Manufacturing ▪ Classification N ▪ Manufacturing brings in 25% of EL the nation’s GDP (Gross Domestic Product) revenue. PT ▪ India is a country highly reliant on manufacturing. The value of manufacturing in India is $ 403 N billion in 2019. https://www.vectorstock.com/1631974 ▪ As manufacturing scenario witnessed a change in the technology, Additive Manufacturing process have emerged as EL one of the most efficient methods. ▪ This course covers Metal Additive Manufacturing that is an PT emerging phenomenon being put into practice N ▪ Introduced the industrial age in 18th century, Mass production is when products are created in large numbers. EL ▪ Large industries producing 1000s of units every hour PT ▪ Today, we slowly move towards ‘Mass Customization’. Every customer demands a product to their specific need ▪ Customization units create products with N high variety and low volumes https://pixabay.com/vectors/factory-plant-assembly-line-35081/ ▪ Take the example of a cobbler. Shoes produced are of different sizes – Customization. ▪ However, it is not ”mass” customization as it does not EL happen on a large scale. ▪ Mass customization is based on the idea of tying computer-based information systems with flexible- manufacturing systems, to produce customized PT products to meet the demands of different segments of customers. N https://www.vectorstock.com/1631974 https://www.istockphoto.com/1050225480-280835824# Requirements for mass customization systems EL 1. Computer-based information system. 2. Flexi-manufacturing systems PT 3. Instant communication media – email, image chat, cloud systems, etc. N Examples of Mass customization: EL ▪ Levi’s customized jeans ▪ Laser engraved products PT N https://www.pinterest.com/pin/2070249141156683 63/ https://www.istockphoto.com/1050225480-280835824# INDUSTRIAL REVOLUTION EL PT N https://www.spectralengines.com/articles/industry-4-0-and-how-smart-sensors-make-the-difference  EL PT N https://medium.com/@winix/industry-4-0-the-digital-technology-transformation-b23ba02a7dd2 AM AND SUSTAINABILITY EL PT N Machado, Carla Gonçalves, et al. "Additive manufacturing from the sustainability perspective: Proposal for a self-assessment tool." Procedia CIRP 81 (2019): 482-487. N PT EL 1. Jobbing manufacturing process EL 2. Batch manufacturing system 3. Mass or flow manufacturing system 4. PT Process type manufacturing system N  1. Job manufacturing process ▪ Job shop production ▪ Varieties of products produced in small amounts EL 1. Painting shops 2. Machine tool shops PT N https://www.gopracticals.com/workshop/painting-workshop-introduction-tools-precautions/ https://kosmomachine.com/2016/12/what-is-a-machine-shop/ 2. Batch manufacturing system EL ▪ Batch Production ▪ Products in lots/ groups/batches ▪ Medium variety PT ▪ Medium volumes/medium quantity ▪ Example: Drugs and pharmaceuticals, chemicals N 3. Mass or flow manufacturing system ▪ Mass/flow/in-line production EL ▪ Low variety ▪ High volume PT ▪ Example: automobile plants, food processes, beer bottling N 4. Process type manufacturing system EL ▪ Process/continuous flow production. ▪ 24x7 production all over the year. ▪ Very high volume. ▪ Very low variety. PT ▪ Example: petrochemical refineries, edible oil refineries, steel making, paper making, beer brewing N 1. Effect of volume/variety EL 2. Capacity of plant 3. Lead time 4. PT Flexibility and efficiency N Understanding the basics of manufacturing EL Any product can be manufactured by a combination of the below process: PT 1. Constant Volume Process 2. Subtractive Process N 3. Additive Process 1. Constant Volume Processes ▪ Casting is the process where metal is heated until molten. While in the molten or liquid state it is poured into a mold or vessel to create EL the desired shape. ▪ Forging is the application of thermal and mechanical energy to steel billets or ingots to cause the material to change shape while in a solid-state. PT N https://www.theweldingmaster.com/what-is-arc-welding-how-arc-welding-works/ 2. Subtractive (Machining) Processes EL PT N https://www.theweldingmaster.com/what-is-arc-welding-how-arc-welding-works/  MANUFACTURING SYSTEMS 3. Additive (joining) process ▪ In this process, additional EL material is added to the workpiece to get desired shape and form PT ▪ Welding is one of the most commonly used processes – it is used to join parts of metal N together. https://www.theweldingmaster.com/what-is-arc-welding-how-arc-welding-works/ ▪ All the above manufacturing processes deal only in 2D or 2.5D – To obtain 3D parts, a combination of processes must be used. ▪ Today, however, we look at shortening lead times and expediting product life cycles EL ▪ That is where Rapid Prototyping comes in PT N https://www.arch2o.com/new-way-heal-broken-bones-3d-printed-cast-3d-molds-exoskeletal/ ▪ Manufacturing process to form 3D object from CAD model by the addition of layers. EL ▪ ASTM International defines Additive Manufacturing (AM) as: PT “the process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies” N  EL PTTRADITIONAL MANUFACTURING FINAL PRODUCT WASTE N ADDITIVE FINAL WASTE MATERIAL MANUFACTURING PRODUCT https://www.3dnatives.com/en/3d-printing-vs-cnc-1603a20184/  EL PT N https://www2.deloitte.com/content/dam/Deloitte/de/Documents/operations/Deloitte_Challenges_of_Additive_Manufacturing.pdf 1. AM fabricates part layers by manufacturing successive cross- sectional layers of any part. EL 2. The process starts with a 3D solid model which is either modeled PT or scanned as a CAD file. It is then sliced in a number of layers depending upon resolution by preparation software. N 3. Design Flexibility: Layer wise fabrication approach enables AM to manufacture parts of almost any level of complexity with less material usage and reduced mass. 4. Cost of geometric complexity: With complex designs, there EL is no need for additional tooling, re-fixturing, increasing expertise of the operator, or even manufacturing time. 5. PT Dimensional accuracy: Most AM machines have the capability of several hundreds of a millimeter of tolerance. N 6. Need for assemblage: AM is capable of producing ‘single– part assemblies’ products that have integrated mechanisms. EL The parts and joints are printed using support structures that are suspended in the air. It is then removed in the post- processing operations. 7. PT Time and cost-efficient: No tooling required. On-demand and on-location manufacturing reduce inventory costs. Little N waste of material  3D Printing EL Material Extrusion Vat Polymerizatio n PT Powder Bed Fusion (Polymers) Material Jetting Binder Jetting Powder Bed Fusion (Metals) N Fused Stereo- Material Binder Selective Direct Metal Laser Filament Lithography Jetting Jetting Laser Sintering (DMLS) Fabrication Appratus Sintering (FFF) Direct Lase Selective Laser Printing Melting (SLM) Electron-beam Melting (EBM) N PT EL N PT EL  EL PT N https://medium.com/@DAUNow/an-introduction-to-additive-manufacturing-7c468d099f2c 1. Why do we need to learn Additive Manufacturing? EL 2. What is Mass Customization? 3. How is the current industrial revolution working? 4. 5. 6. PT What are Manufacturing Systems? What is the need for Additive Manufacturing? An introduction to Additive Manufacturing N 1. Google and find out some applications and fields in which Additive manufacturing is used EL 2. We will discuss a wide variety of applications in our next lecture PT N N PT EL  EL PT N Dr. J. Ramkumar Professor Department of Mechanical Engineering and Design IIT Kanpur ▪ AM: A Long-term game changer. EL ▪ AM Classification. ▪ Why Metal AM? PT ▪ Current and future estimation of AM market size. ▪ Application of metal AM in different sectors. N ▪ AM Challenges and opportunities. ▪ Understand the standard definition of additive manufacturing EL (AM) and seven standard classes of AM processes ▪ Gain basic knowledge of AM market size the AM industry PT ▪ Gain basic knowledge of opportunities, threats, and trends in ▪ Gain insight into applications of metal AM N ▪ Additive manufacturing (AM), often known as 3D printing, is a EL layer-by-layer fabrication technology ▪ AM is a platform that converts digital models to physical parts in a short chain of procedures, or "Art" to "Part" in a fancy analogy. ▪ Industrialized PT countries are researching AM to recover manufacturing leadership through innovation N ▪ The world economy is nearing "Industry 4.0," the fourth industrial revolution. ▪ This new production method has gained international attention. AM innovations are reported every week. ▪ the worldwide economic impact will be $550 billion per year by 2030  EL ▪ As interest in AM grows, several sectors are incorporating it into their products and services. Aerospace, medical, automotive, tooling, energy, natural resources, consumer, and defense have embraced AM methods. PT ▪ The 2020 pandemic revealed that digital files and affordable 3D printers can fill medical supply gaps. Internet accounts indicate that people printed face shield parts during the pandemic supply chain disruption. N ▪ Thisfeature encourages the industry to focus on localized manufacturing to handle on-demand manufacturing with little foreign dependence.  EL ▪ When the skill gap is a key barrier to the adoption of AM in industry, AM-based courses are being added to the school, college, and university curricula to educate AM to youth PT ▪ This paradigm shift requires knowledge of AM principles, technology, and software, and efforts are underway to integrate these into educational platforms. N ▪ “Additive manufacturing (AM) is process of joining materials to make parts from 3D model data, usually layer upon layer, as EL opposed to subtractive manufacturing and formative manufacturing methodologies.” ▪ Standard categories of AM PT 1. Binder Jetting 2. Directed Energy Deposition 3. Material Extrusion N 4. Material Jetting 5. Powder Bed Fusion 6. Sheet Lamination 7. VAT Photopolymerization  EL PT N https://manufacturing.report/articles/which-additive-manufacturing-process-is-right-for-you 1. Binder jetting uses a liquid bonding agent to combine powder materials. 2. Directed energy deposition, an additive manufacturing EL technology that melts materials as they're deposited. 3. Material Extrusion: Material is extruded through a nozzle or aperture in additive manufacturing. 4. PT Material jetting is a droplet-based additive manufacturing technology. Photopolymer and wax are examples. N 5. In Powder bed fusion, thermal energy selectively fuses powder bed regions. 6. Sheet lamination is an additive manufacturing process that bonds sheets to make an object. 7. Vat photopolymerization selectively cures liquid photopolymer in a vat using light 1. On-demand low-cost rapid prototyping EL 2. Simpler supply chain for effective low-volume production 3. Geometric complexity may be free 4. Light weighting 5. 6. PT Parts consolidation Functionally graded materials (FGMs) and structures (FGSs) N 7. Parts with conformal cooling channels for increased productivity 8. Parts repair and refurbishment 1. On-demand low-cost rapid prototyping EL ▪ Functional prototypes are made with AM. ▪ Such prototyping costs a fraction of standard procedures and is fast. PT ▪ This quick turnaround speeds up design (design, test, revision, and redesign). ▪ AM can develop moulds that would take 4–6 months in 2–3 N months. 2. Simpler supply chain for effective low-volume production EL ▪ Low-volume specialty production costs more. Due to this challenge, conventional manufacturers avoid low-volume production. AM firms can fill this gap. PT ▪ Metal AM can replace time-consuming and expensive low- volume manufacturing processes. AM lags behind casting and forging for bulk production. N ▪ AM usually requires a simpler supply chain with fewer stakeholders.As AM's supply chain develops, low-volume production should increase. 2. Simpler supply chain for effective low-volume production EL ▪ When AM develops into series manufacturing, lower material prices will boost low-volume adoption. ▪ AM has cheaper initial costs than conventional processes since fewer tools and jigs/fixtures are needed. PT ▪ To offset tooling costs, the quantity of items should be high. AM doesn't require specialist tools, thus there are no upfront costs (called fixed costs too). This allows you to reach N breakeven sooner and make profits with lesser volumes. 3. Geometric complexity may be free EL ▪ AM can make complicated shapes that other technologies couldn’t ▪ AM's additive nature allows geometric complexity to be cost- ▪ effective. AM allows "design for use" instead of "design for manufacture" Complex or organic parts designed PT N ▪ for performance may cost less, but not all are AM-manufacturable. Complex parts made by AM. ▪ Overhanging features may produce residual stresses and flaws in metal AM, therefore complexity may not equal freedom. Toyserkani, Ehsan, Dyuti Sarker, Osezua Obehi Ibhadode, Farzad Liravi, Paola Russo, and Katayoon Taherkhani. "Metal additive manufacturing." (2021). 4. Light weighting ▪ Manufacturers make greener and cheaper products. EL ▪ Lightweight components reduce energy utilization and raw material use. ▪ Lightweight components reduce costs, resources, and the environment for both reasons. PT N Lightweight structure made by AM Toyserkani, Ehsan, Dyuti Sarker, Osezua Obehi Ibhadode, Farzad Liravi, Paola Russo, and Katayoon Taherkhani. "Metal additive manufacturing." (2021). 4. Light weighting EL ▪ AM is coupled with topology optimization, allowing it to design and manufacture high-strength, lightweight structures. PT ▪ Topology optimization and lattice structure design work with AM to create lightweight structures. ▪ Aerospace uses several lightweight, high-strength parts. Any weight decrease saves money on parts and fuel. N 5. Parts consolidation ▪ Industrial products have mechanical assembly. In sophisticated mechanical machinery, components are welded, bolted, or press- EL fit together. ▪ Parts consolidation reduces the number of individual parts that must be designed, manufactured, and assembled. PT ▪ Part consolidation has many advantages. i. design simplification; ii. reduced overall project costs; N iii. reduced material loss; iv. reduced weight; v. reduced overall risk as the number of suppliers of individual parts drops; vi. improved overall performance as it enables desirable geometries not possible with conventional manufacturing. 6. Parts consolidation ▪ AM facilitates parts consolidation, sometimes eliminating assembly. ▪ AM can improve product performance by EL lightweighting/consolidation without losing high strength by optimizing heat sinks, fluid flow, and energy absorption. ▪ Figure demonstrates GE Additive's work. The A-CT7 engine PT frame combines about 300 pieces. This consolidation cut 10 pounds from seven assemblies N M. Shaw, “Lessons learned from commercial aviation certification,” 2017. [Online]. Available: https:// www.nsrp.org/wp- content/uploads/2019/10/Lessons-Learned-From-Commercial-Aviation-Certification.pdf  EL 7. Functionally graded materials (FGMs) and structures (FGSs) ▪ Multiple advanced materials in one component are a fast- growing AM field. PT ▪ AM may generate multiphase materials with progressive composition changes. ▪ AM processes adjust material composition layer-by-layer to achieve the desired functionality. N 7. Functionally graded materials (FGMs) and structures (FGSs) EL ▪ AM also permits FGSs with a single-phase material, where the density is gradually modified by adding cellular/lattice structures and embedding things (e.g. sensors) within structures. ▪ DED is the most promising AM technique PT N for developing such structures because it can switch powders in-situ to generate appropriate composition and alloys A cutting tool with an embedded fiber optic, developed by an AM- based process H. Alemohammad, E. Toyserkani, and C. P. Paul, “Fabrication of smart cutting tools with embedded optical fiber sensors using combined laser solid freeform fabrication and moulding techniques,” Opt. Lasers Eng., vol. 45, no. 10, 2007.  ▪ Parts repair and refurbishment EL ▪ Machining faults or last-minute technical revisions might delay tools supply and product launch. ▪ AM, especially DED techniques, can safely repair tools, especially contacting surfaces. PT N ▪ AM can save a high-value tool that would otherwise be replaced LDED used to rebuild turbine blades T. Boon, “Rolls royce to revolutionise engine maintenance with ‘snakes and beetles’,” 2017. [Online]. Available: https://simpleflying.com/rolls-royce-engine-maintenance. ▪ Parts with conformal cooling channels for increased productivity EL ▪ Many parts' productivity and performance depend on their cooling systems. ▪ In injection moulding, cooling accounts for almost 40% of cycle time. PT Productivity increases considerably if this period is shortened by removing mould heat. ▪ In an active antenna, constructing conformal channels is crucial so that heat may be drained from the zone without affecting antenna N performance. ▪ Parts with conformal cooling channels EL for increased productivity ▪ With AM, designers can incorporate conformal cooling channels that promote uniform cooling over the entire surface. ▪ Optimization can incorporate sub- conformal channels. PT A mold insert with (a) N conformal cooling channels, ▪ The concept uses support cells to and (b) conformal and lattice increase heat transmission in a structures to improve heat conformal cooling channel. dissipation. Toyserkani, Ehsan, Dyuti Sarker, Osezua Obehi Ibhadode, Farzad Liravi, Paola Russo, and Katayoon Taherkhani. "Metal additive manufacturing." (2021).  EL PT N R. Nolan, “SmarTech publishing issues 2019 additive manufacturing market outlook and summary report, estimates AM industry grew 24% percent in 2018, total market of $9.3 billion,” 2018. [Online] ▪ AM process and ASTM definition. EL ▪ Importance of AM and its major classification. PT N N PT EL  EL PT N Dr. J. Ramkumar Professor Department of Mechanical Engineering and Design IIT Kanpur ▪ Current and future estimation of AM market size. EL ▪ Application of metal AM in different sectors. ▪ AM Challenges and opportunities. PT N  EL PT N R. Nolan, “SmarTech publishing issues 2019 additive manufacturing market outlook and summary report, estimates AM industry grew 24% percent in 2018, total market of $9.3 billion,” 2018. [Online]  EL PT N R. Nolan, “SmarTech publishing issues 2019 additive manufacturing market outlook and summary report, estimates AM industry grew 24% percent in 2018, total market of $9.3 billion,” 2018. [Online]  EL PT N R. Nolan, “SmarTech publishing issues 2019 additive manufacturing market outlook and summary report, estimates AM industry grew 24% percent in 2018, total market of $9.3 billion,” 2018. [Online]  a) Dental crowns printed by EL LPBF b) Joint implants printed by E- LPF c) Functionally porous titanium gradient load- bearing hip implant printed PT N by LPBF d) Customized ribs and sternum printed by E-PBF S. Fournier, “The making of an orthopedics implant using 3D printing.” [Online], 2018. Available: https:// orthostreams.com/2018/12/the-making-of-a-medical-metal-implant-using-3d- printing-from-black-to-greymetal-powder-magic-of-3d-printing. Metal AM, “Renishaw showcases metal AM implants to American Academy of Orthopaedic Surgeons,” 2018. [Online]. Available: https://www.metal-am.com/renishaw-showcases- metal-implants-americanacademy-orthopaedic-surgeons. H. R. Mendoza, “3D printing gives cancer patient new ribs and sternum in first-of-its-kind surgery,” 2015. [Online]. Available: https://3dprint.com/95371/3d-printed-ribs-and-sternum  EL PT N A mold insert with (a) conformal cooling channels, and (b) conformal and lattice structures to improve heat dissipation. R. Botsford End, “SpaceX’s superdraco engine: Abort capability all the way to orbit,” 2015. [Online]. Available: https://www.spaceflightinsider.com/organizations/space-exploration-technologies/spacexssuperdraco-engine.  EL PT N Small-size, lightweight, one-piece, AM-made antenna. Optisys, “Additive manufacturing transforms RF antenna design,” Metal AM, 2017. [Online]. Available: https://www.metal-am.com/additive-manufacturing-transforms-rf-antenna-design  EL PT N Hydraulic parts made for the oil and gas industry R. Nolan, “SmarTech publishing issues 2019 additive manufacturing market outlook and summary report, estimates AM industry grew 24% percent in 2018, total market of $9.3 billion,” 2018. [Online]  a) Ford’s custom anti-theft wheel lock being printed EL by PBF system b) Ford’s custom anti-theft c) wheel lock Custom titanium door handle frame in DS3 Dark Side edition from DS PT N Automobile EOS, “The potential of additive manufacturing for serially produced vehicles.” [Online]. Available: https:// www.eos.info/en/3d-printing-examples- applications/mobility-logistics/automotive-industry-3d-printing/ serially-produced-vehicles. Ford, “Ford develops 3D-printed locking wheel nuts to help keep thieves at bay,” 2020. [Online]. Available:https://media.ford.com/content/fordmedia/feu/en/news/2020/01/28/ford-develops-3d-printed-lockingwheel-nuts-to-help-keep-thieves.html. ▪ AM can be used to produce machinery components, heat exchangers, engineered structures, etc., either for redesigned EL parts or low-volume production of heritage parts. ▪ Mass customization promotes the expanding use of metal AM in design PT consumer products such as decorative objects, jewelry, specialized sports gear, and bicycle frames. ▪ AM's freeform, material graded structures, lightweighting, and the quick design-to-market cycle will N revolutionize industrial and personal product markets. 1. Qualified materials EL 2. Speed and productivity 3. Repeatability and quality assurance 4. 5. 6. PT Industry-wide standards End-to-end workflow, integration, and automation Software limitations N 7. Initial financial investments 8. Security 9. Skillsets gap 1. Qualified materials EL ▪ Number of powders qualified for use with metal AM systems, including laser, electron beam, and binder-based AM techniques, is a key difficulty in metals and metal alloys. ▪ More than 1000 steel alloys are commercially accessible for for AM. PT conventional casting, but only a handful have been validated ▪ Aluminum alloys are 600:12. N ▪ The lack of parts limits the number of companies that can use the technology. 1. Qualified materials EL ▪ The few qualified metals AM powders cost 5–10 times more than casting, machining, and other raw materials. ▪ Uncompetitive suppliers are part of the problem. PT ▪ Metal AM materials sales total less than $400 million a year, a fraction of the whole raw materials business. ▪ As AM gains popularity, pricing should drop drastically. This difficulty presents an opportunity to improve powder N production procedures and maybe manufacture new powders to maximize metal AM 2. Speed and productivity EL ▪ AM procedures require speed. Mass production speeds are modest. ▪ Small working volume and post-processing for surface enhancement add steps to manufacturing time. PT ▪ To boost AM production, surface quality must be improved. ▪ To boost AM productivity, modular flexibility is being added. N ▪ Process scalability and modularity can help achieve quality and speed. 2. Speed and productivity EL ▪ Multiple heat sources (e.g. laser beams) are being combined into a larger operating envelope. ▪ Automation and intelligent software are being developed to improve subsystem production. PT ▪ Computer modeling of AM processes can enhance production through dependable simulation rather than costly experimentation. N ▪ Few models have been developed, adding R&D costs to high material costs to prevent enterprises from using AM. 3. Repeatability and quality assurance EL ▪ Reliability and reproducibility remain major AM issues, especially for mass manufacturing. ▪ AM is sensitive to environmental and process disturbances including shifting temperature, humidity, and particle size. PT ▪ Full control of the process and environment is difficult, thus solutions that use sensors to monitor conditions and quality control algorithms to automatically modify process N parameters, such as laser power or process speed, are preferred. ▪ Due to their speed, DED is adding closed-loop control while PBF is adding intermittent controllers. ▪ For PBF operations (e.g. LPBF), hardware speed and accuracy are bottlenecks for closed-loop control. 4. Industry-wide standards EL ▪ Despite AM's recent advances, the industry lacks a complete set of technical standards. ▪ Lack of standards may hamper industrial AM adoption. PT ▪ Several key players have identified the challenge and begun acting. ASTM, ANSI, ISO, and other organizations are developing AM standards platforms and methods. N 4. Industry-wide standards ▪ ASTM's F42 committee is creating standards for metal AM, EL particularly LPBF. ▪ The created standards could assist the industry to analyze AM system performance and part quality. needed. PT ▪ Despite these efforts, new, dependable standards are ▪ Concrete standards should be published rather than partially created ones with shortcomings. N ▪ If standards are repeatedly retracted and amended owing to weaknesses, the industry will suffer. 5. End-to-end workflow, integration, and automation EL ▪ All major industrial and nonindustrial AM system providers propose end-to-end workflow integration. ▪ Any integration/automation must consider AM's limitations and features. PT ▪ The lack of digital infrastructure hinders the AM industry's progress to automated workflows. N 5. End-to-end workflow, integration, and automation ▪ Design for AM (DfAM) solutions, driven by digital EL warehouses and digital twins, expedite the part design and optimization for automation. ▪ Manufacturing execution software should automate material supply lines (e.g. powders) for AM systems and workflow stations. PT ▪ Machine learning, AI, simulation, inline process monitoring software, and nondestructive testing (NDT) should oversee N the AM process to fix faults by having robots for depowdering and recycling powder for AM machines. ▪ The workflow should include automated post-processing heat treatment, polishing, etc. Automated AM is part of the factory of tomorrow and the industry 4.0 revolution. 6. Software limitations EL ▪ Commercial software systems for AM component design, support structure construction, and machine interface have limitations in assessing print feasibility and recognizing process limits. PT ▪ In many cases, 3D-modeled ideas are difficult to print due to unaccounted-for process restrictions. ▪ Current workflow software limits AM's ability to track N individual goods through each process stage to manage resources and delivery timelines. ▪ The quality of information and transmission mechanisms affects inter-and intra-communication and collaboration. ▪ Current software and hardware need enhancements for AM communication. 7. Initial financial investments EL ▪ A large investment in AM money and ecosystem is required to put metal AM into production. ▪ AM includes software, supplies, experts, post-processing equipment, certification, and employee training. technology. PT ▪ This investment may prevent companies from adopting this ▪ AM service firms can be integrated throughout the supply N chain to derisk early AM adoption. ▪ Universities and R&D institutions can help companies implement AM by providing basic R&D and training platforms. 8. Security ▪ AM’s cyber-physical nature has caused considerable EL problems. ▪ When AM promotes distributed manufacturing, hackers exist. PT ▪ They can change AM designs to generate purposeful faults with catastrophic effects in real systems. ▪ Commercial AM services' weaknesses and large-scale tasks N may make it hard to verify printed parts' quality. 8. Security ▪ To solve security problems, process and supply chains must EL be firewalled. ▪ These measures could be the same as other manufacturing industries like electronic printing PT ▪ However, due to typical applications of AM-made parts in critical applications like jet engines, special validation procedures must be developed to give assurance that the parts are not affected by a malicious attack involving N undetectable design alterations. 9. Skillsets gap ▪ AM expertise is in scarce supply. EL ▪ Lack of AM knowledge and competence hinders adoption. ▪ There is a restricted workforce and highly qualified specialists to help new enterprises adopt AM. PT ▪ A thorough understanding of AM capabilities minimizes significant misconceptions and introduces decision-makers to difficulties correctly. ▪ Companies struggle to establish successful metal AM N business cases due to a knowledge gap. ▪ Mechanical engineers educated in traditional production can't design for AM. Mastering it will be difficult. ▪ Education and training must modify their perspective. ▪ Metal AM's capabilities and limitations will help organizations design effective applications. ▪ AM process and ASTM definition. EL ▪ Importance of AM and its major classification. ▪ Application in different sectors. PT ▪ Challenges and opportunities in Metal AM N 1. Google and make a list of seven major categories of AM process, advantages and limitations of each process. EL 2. Point out the AM process which can manufacture metal parts. PT N N PT EL  EL PT N Dr. J. Ramkumar Professor Department of Mechanical Engineering and Design IIT Kanpur ABSORPTION EL ▪ The process of one material (absorbate) being retained by another (absorbent). PT ▪ In Metal Additive Manufacturing, some defects such as porosity, keyhole comes into play due the phenomenon of gas absorption in molten phase of metal. N AM GUIDELINES AND STANDARDS ▪ Control of hazards caused by combustible materials has been measured in the last decades. EL ▪ For example, the well-known ATEX directions and ISO standards (mainly ISO 60079) are applied in the European Union and some other countries. PT N ADDITIVE MANUFACTURING EL ▪ Additive Manufacturing (AM) is the process of joining materials to make parts from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing and formative manufacturing methodologies. PT N ANALYTICAL MODELING ▪ An analytical model is quantitative in nature, and used to EL answer a specific question or make a specific design decision. PT ▪ Different analytical models are used to address different aspects of the system, such as its performance, reliability, or mass properties in Metal Additive Manufacturing. N  BALLING EL ▪ The balling phenomenon is considered as the unusual melt pool segregation/breakout that may take place on the surfaces of the laser additive manufactured parts, especially laser powder bed fusion. PT N Singla, Anil Kumar, et al. "Selective laser melting of Ti6Al4V alloy: Process parameters, defects and post-treatments." Journal of Manufacturing Processes 64 (2021): 161-187. CAD/CAM SOFTWARE. EL ▪ Different software is used for the 3D design of the parts that need to be printed, for scanning, improving the performance of the part, and for process simulation studies. ▪ Examples of software that are being employed are Power PT mill, NX Cam, and Mastercam. N CAPILLARY NUMBER The capillary number (Ca) is a dimensionless EL quantity representing the relative effect of viscous drag forces versus surface tension forces acting across an interface between a liquid and a gas, or between two immiscible liquids. The capillary number is defined as: PT Ca = capillary number μ = fluid viscosity N V = fluid velocity σ = surface or interfacial tension The capillary number is defined as the ratio of viscous to interfacial forces and is used to study the microscopic displacement of the polymer. CLASS X LASER X Definition 1 These are lasers that are not hazardous for continuous viewing or are designed to prevent human access to laser radiation. These consist of EL low-power lasers or higher-power embedded lasers (e.g. laser printers). 2 These are the lasers emitting visible light that, because of normal PT human aversion responses, do not normally present a hazard but would if viewed directly for extended periods (i.e. many conventional light sources). N 3B These are the lasers that present an eye and skin hazard if viewed directly. This includes both intra beam viewing and specular reflections. Class 3B lasers do not produce a hazardous diffuse reflection except when viewed at close proximity. 4 Lasers that present an eye hazard from direct and specular reflections. Besides, such lasers may be fire hazards and produce skin burns. CLOSED LOOP CONTROL ▪ Closed-loop control of the process will monitor one of the process parameters (e.g. deposition temperature) in real-time in order to EL compare it with the desired value. Then, a controller takes the difference between the measured and desired values and sends a signal to an actuator(s) to tune one or more process parameters. PT N https://www.techtarget.com/whatis/definition/closed-loop-control-system  COAXIAL NOZZLE ▪ In this type of nozzle, the powder flow, the laser beam, and the shied gas are delivered from the same nozzle. LATERAL NOZZLE ▪ In the AM process equipped with a later nozzle, the powder EL is delivered from the side and an inert gas passing through the nozzle helps in the powder delivery stream while preventing the oxidation of the deposit PT N Metal Additive Manufacturing, First Edition. Ehsan Toyserkani, Dyuti Sarker, Osezua Obehi Ibhadode, Farzad Liravi, Paola Russo, and Katayoon Taherkhani. © 2022 John Wiley & Sons Ltd. Published 2022 by John Wiley & Sons Ltd. COLLATERAL RADIATION EL ▪ Radiation other than that associated with the primary laser beam is called collateral radiation. For example, X-rays, UV, plasma, and radiofrequency emissions are collateral radiation. PT N COMBINED THERMAL ENERGY SOURCE PARAMETERS EL ▪ Parameters such as beam power, operation mode, focused spot diameter (D), beam profile, and wavelength (λ) are critical factors in the selection and processing of materials in PBF and DED systems ▪ Due to the high interdependency of energy and other process PT parameters on the melt pool temperature and dimensions, it is common practice to use a combined process parameter to measure the volumetric energy density (VED) or surface energy density (SED) in metal AM N COMPUTED TOMOGRAPHY ▪ The term Computed Tomography, or CT, refers to a computerized x- EL ray imaging procedure in which a narrow beam of x-rays is aimed at a patient and quickly rotated around the body, producing signals that are processed by the machine’s computer to generate cross- sectional images or slices. PT ▪ These slices are called tomographic images and can give a clinician more detailed information than conventional x-rays. N COOLING CURVE ▪ A cooling curve is a graphical presentation of the phase transition temperature with time for pure metals or alloys over a complete temperature range through which it cools. When a EL pure liquid metal cools, it first reaches the melting point (a unique temperature) and then solidifies. PT N https://www.researchgate.net/figure/Figure33-Cooling-curve-for-a-pure-metal_fig1_340444469 CRACKING ▪ Cracks are detected in metal AM processed products. The EL solidification cracking in AM products occurs along the grain boundaries, similar to what would normally happen in conventional welding. PT N Wahlmann, Benjamin, et al. "Numerical alloy development for additive manufacturing towards reduced cracking susceptibility." Crystals 11.8 (2021): 902. DESIGN FOR METAL ADDITIVE MANUFACTURING EL ▪ Maximizing product performance through the synthesis of shapes, sizes, hierarchical structures, and material compositions, subject to the capabilities of AM technologies. PT DESIGN OF SUPPORT STRUCTURE ▪ A support structure design technique for additive N manufacturing (AM) is proposed that minimizes the deformation while using the least amount of support material, minimizes the time required to add the supports, and designs supports that are easily removed. DIRECTED ENERGY DEPOSITION (DED) ▪ Directed energy deposition (DED) technology involves using a heat source such as a laser, electron beam, or a gas- EL tungsten arc to create a melt pool and adding filler materials in powder or wire form into the melt pool. The process follows a toolpath created directly from the CAD geometry and builds up parts in successive layers. PT DIRECT METAL LASER SINTERING (DMLS) N ▪ In this process, each layer of a part is created by aiming a laser at the powder bed in specific points in space, guided by a digitally produced CAD (computer-aided design) file. Once a layer is printed, the machine spreads more powder over the part and repeats the process DROPLET FORMATION EL ▪ A column of the liquid ejecting from a nozzle starts to break into a droplet as the interfacial tensions try to minimize the surface area leading to capillary instabilities. PT ▪ This process is highly affected by the properties of the liquid, such as viscosity and surface tension, as well as the printhead process parameters such as the shape and N amplitude of pressure signals generated by the piezoelectric transducer. DROP-ON-DEMAND. ▪ An Inkjet methodology is now incorporated in rapid EL prototyping systems, where the material is deposited in a non-continuous stream. Drops are produced and deposited only as required. Or When a nozzle releases PT a droplet where needed, known as drop-on-demand. N https://epsvt.com/what-is-drop-on-demand-printing/ EFFECTIVE LAYER THICKNESS ▪ In LPBF, it is reported that “the actual thickness of powder particles that spread on solidified zones, so-called effective layer thickness (ELT), is higher than the nominal layer thickness, the powder particles shrink substantially after EL melting and solidification. PT N https://aiche.onlinelibrary.wiley.com/doi/epdf/10.1002/amp2.10021 ELECTRON BEAM ▪ In addition to the laser beam, another common source of heat EL for thermal-based metal powder bed additive manufacturing technologies is the electron beam (EB or EBM). PT N Rahmati, S. "Advances in additive manufacturing and tooling." Compr. Mater. Process 10 (2014): 303-344. FLOWABILITY ▪ The capacity to move by flow that characterizes fluids and loose EL particulate solids FOURIER’S LAW ▪ Heat transfer processes can be quantified in terms of appropriate PT rate equations. This law states that the time rate of heat transfer through a material is proportional to the negative gradient in the temperature and to the area, at right angles to that gradient, through which the heat flows. Its differential form is N FUNCTIONALLY GRADED LATTICES ▪ Structures that are designed using lattices with varying EL distribution of porosity by virtue of varying the volume fractions of each unit cell in the 3D design domain PT N https://www.mdpi.com/2313-7673/5/3/44/htm GRADED LATTICE ▪ The graded lattice structure is built by repeatable unit cells in a 3D framework by using the implicit surfaces derived from the triply periodic minimal surface (TPMS) particularly: EL Diamond, Gyroid, and Primitive PT N Metal Additive Manufacturing, First Edition. Ehsan Toyserkani, Dyuti Sarker, Osezua Obehi Ibhadode, Farzad Liravi, Paola Russo, and Katayoon Taherkhani. © 2022 John Wiley & Sons Ltd. Published 2022 by John Wiley & Sons Ltd. Kladovasilakis, Nikolaos, Konstantinos Tsongas, and Dimitrios Tzetzis. "Finite element analysis of orthopedic hip implant with functionally graded bioinspired lattice structures." Biomimetics 5.3 (2020): 44. HATCH SPACING/HATCHING DISTANCE/SCAN SPACING ▪ It is the separation between two consecutive laser beams. EL PT N HEATING DEPTH RATIO (HDR) EL ▪ A logical dimensionless combined process parameter may be proposed through a ratio of the heat depth and layer thickness, leading to a parameter, so-called heating depth ratio (HDR). PT 𝑑 α= heat transfer coefficient N 4𝛼 l = length of the material 𝑣 𝐻𝐷𝑅 = d = spot diameter 𝑙 v = scan velocity IMAGE SEGMENTATION ▪ Image segmentation is a method in EL which a digital image is broken down into various subgroups called Image segments which helps in reducing the complexity of the image to make further processing or analysis of the image simpler. Segmentation in easy words is assigning labels to pixels. All PT N picture elements or pixels belonging to the same category have a common label assigned to them. Ay, Mustafa, et al. "3D Bio-CAD modeling of human mandible and fabrication by rapid- prototyping technology." Usak University Journal of Material Sciences 2.2 (2013): 135-145. INTERGRANULAR CRACKING ▪ Cracking arises at the grain boundaries during the last step of the solidification, where solidifying and cooling material possesses higher tensile stresses EL compared to the strength of the solidified metal. Intergranular cracking is worsened by the intensification of thermal power or thickness of the substrate. PT N https://en.wikipedia.org/wiki/Intergranular_fracture  EL INTRINSIC ▪ Intrinsic parameters are those related to the substrate and powder properties. Some of these parameters include PT absorptivity, thermal conductivity, heat capacity, thermal diffusivity, and substrate geometry. N KEYHOLE ▪ Keyhole pores are formed when the vapor bubbles are trapped within the melt pool, which occurs at higher energy EL densities, and lack of fusion pores are formed when some regions remain unmelted as a result of lower energy density. PT N https://www.industrialheating.com/articles/95529-finding-keyholes-in-metal-additive-manufacturing LACK OF FUSION ▪ Improper selection of laser power, scanning speed, laser spot radius, layer thickness, hatch spacing, and alloy affect the formation of this defect. Because of the involvement of many process parameters and alloys, EL currently, there is no generally available methodology to guide engineers to avoid this defect. PT N https://www.epowermetals.com/detection-technology-of-metal-additive-manufacturing-defects.html  LAMELLAR TEARING ▪ A Lamellar tearing is caused because of the combined effect of localized internal stresses and the substrate material with lower ductility. The tearing is activated by the de-bonding of non- metallic inclusions such as silicates or sulfides in the substrate EL metal close to the heat-affected zone, where there is no retrieval of grains or reabsorption of precipitates for the homogenization of microstructure. This region of the substrate also receives PT greater thermal stresses because of the higher heat input during the AM processes. N https://www.materialwelding.com/lamellar-tearing-in-welding-carbon-low-alloy-steels/ LASER PULSE SHAPING ▪ Manipulations with the temporal profile of an ultrashort EL laser pulse. PT N https://amadaweldtech.com/technical-glossary/pulse-shaping/ LASER ▪ Laser stands for Light Amplification by Stimulated Emission of Radiation. A laser is a coherent and focused beam of photons. Coherent, in this context, means that it EL is all one wavelength. PT N http://hyperphysics.phy-astr.gsu.edu/hbase/optmod/qualig.html LAYER THICKNESS ▪ Layer thickness in additive manufacturing is a measure of the layer height of each successive addition of material in EL the additive manufacturing or 3D printing process in which layers are stacked. The layer height is essentially the vertical resolution of the z-axis. PT N NUCLEATION ▪ Nucleation is a process that occurs when a new material phase begins to form. EL PT N Mohebbi, Mohammad Sadegh, and Vasily Ploshikhin. "Implementation of nucleation in cellular automaton simulation of microstructural evolution during additive manufacturing of Al alloys." Additive Manufacturing 36 (2020): 101726. PHASE DIAGRAM ▪ Phase diagram is a graphical representation of the physical states of a substance under different conditions of temperature and pressure. A typical phase diagram has pressure on the y-axis and EL temperature on the x-axis. As we cross the lines or curves on the phase diagram, a phase change occurs. PT PHASE TRANSFORMATION Phase transition is when a substance changes from a solid, liquid, or gas state to a different N state. Every element and substance can transition from one phase to another at a specific combination of temperature and pressure PHOTODIODE ▪ Photodiodes are widely used in metal AM as they are inexpensive, where they provide vital information about the process. They are used to sense thermal radiation and light EL emission. PT N https://www.elprocus.com/laser-diode-construction-working-applications/  POROSITY ▪ Porosity refers to the level of solidity achieved in an additively made metal part. EL PT N Hydrogen pores formation in AlSi10 samples built with SLM https://www.insidemetaladditivemanufacturing.com/blog/hydrogen-pore-formations-in-alsi10mg-processed-by-slm RHEOLOGICAL PROPERTIES EL ▪ The most common rheological properties are yield stress, relaxation times, viscosity and compliance. ▪ Rheological properties study the behavior of fluids under mechanical loading. PT ▪ The solid structure, having a defined shape, deforms and stresses when subjected to a load. N SCANNING STRATEGIES ▪ The spatial moving pattern of the energy beam EL PT N Cheng, B., S. Shrestha, and K. Chou. "Stress and deformation evaluations of scanning strategy effect in selective laser melting, Addit. Manuf. 12 (2016) 240–251." SOLIDIFICATION ▪ The conventional and AM techniques follow the solidification scheme, which is the transformation of the liquid metal to solid form through the cooling process. In AM, because of the utilization of moving point power sources with focused energy in the localized area, the short interaction time results EL in a faster solidification rate compared to the conventional technique. PT N Lee, Yousub, et al. "Effect of fluid convection on dendrite arm spacing in laser deposition." Metallurgical and Materials Transactions B 45.4 (2014): 1520-1529.  STAIRCASE EFFECT ▪ It is a phenomenon associated with 3D printing when the layer marks become distinctly visible on the surface of the EL parts, giving the perception of a staircase. The staircase effect is omnipresent in 3D printing irrespective of the technology chosen. PT N Brooks, Hadley, et al. "Variable fused deposition modelling: analysis of benefits, concept design and tool path generation." Proceedings of the 5th International Conference on Advanced Research in Virtual and Rapid Prototyping, Leiria, Portugal. 2011. TOPOLOGY OPTIMIZATION ▪ Topology optimization is a mathematical method that spatially optimizes the distribution of material within a defined domain, by fulfilling given constraints previously established and minimizing EL a predefined cost function. PT N https://engineeringproductdesign.com/knowledge-base/topology-optimization/  UNIT CELL ▪ The smallest repeating unit with full crystal structure symmetry. EL PT N Panesar, Ajit, et al. "Strategies for functionally graded lattice structures derived using topology optimisation for additive manufacturing." Additive Manufacturing 19 (2018): 81-94. WIRE FEED SYSTEM ▪ This type of system is used in Directed Energy Deposition (DED) AM processes, where a solid wire feedstock can be used other than the metal powders. The feedstock capture efficiency is normally 100%, and the volume of the deposit is EL the same as the volume of the wire used as feedstock. PT N https://www.3dnatives.com/en/directed-energy-deposition-ded-3d-printing-guide-100920194/ N PT EL