THURSDAY / 23 MAY / 14:00 / Congress Hall Ragusa / PLENARY SESSION D4-P
DESIGN FOR ADDITIVE MANUFACTURING: IMPLICATIONS FOR SUSTAINABILITY
by Dr. David W. Rosen
Professor Emeritus, Georgia Institute of Technology, College of Engineering, George W. Woodruff School of Mechanical Engineering
Chaired by Sandro Wartzack, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany
Abstract:
Additive manufacturing (AM) is a key digital manufacturing technology leading to Industry 4.0 processes. Its digital input enables great flexibility and adaptability to changing markets, lot-size-of-1 and mass customization, and little if any lead-time since no hard tooling is needed. Its shape complexity capabilities enable part consolidation where several (or many) conventionally manufactured parts can be combined into one part with complex geometry. These characteristics can have major benefits for life-cycle costs and sustainability impacts of products containing AM parts. However, the AM processes themselves are not necessarily more efficient or environmentally friendly than conventional manufacturing (CM) processes. This talk explores opportunities for radically redesigning parts and products to take advantage of the unique capabilities of AM. After a consideration of the sustainability characteristics of AM processes, an analysis is offered of implications for product design. Results of life-cycle analyses (LCA) are highly dependent on the system extent being analyzed. Some alternative system extents are proposed to illustrate their effects. A design strategy is proposed for incorporating sustainability considerations into products and AM processes. Examples are used to illustrate the application of the design strategy. Throughout the talk, the emphasis is on exploring research issues rather than providing quantitative results.
Biographical sketch:
David Rosen is a Principal Research Scientist at the Institute for High Performance Computing and the Singapore Institute for Manufacturing Technology, both A*STAR institutes in Singapore. He was a Professor in the School of Mechanical Engineering at the Georgia Institute of Technology for many years. Additionally, he held faculty and research positions at the Singapore University of Technology & Design. He received his Ph.D. at the University of Massachusetts in mechanical engineering. His research interests include computer-aided design, additive manufacturing (AM), and design methodology, with a specific interest in design for additive manufacturing. He is a Fellow of ASME. Also, he is the recipient of the 2013 Solid Freeform Fabrication Symposium, International Freeform and Additive Manufacturing Excellence (FAME) Award and is a co-author of a leading textbook on AM. In the standards community, he chairs the ASTM F42 subcommittee on design for additive manufacturing and was awarded the ASTM Award of Merit and promoted to Fellow of ASTM.
to lead you through the next session and before I do that I want to thank thank you very much I want to thank Mario sta for the really nice conference dinner yesterday evening it was he did a great job here and his team so Mario thank you very much for this really nice [Applause] evening yes and now I have the great honor to present to int introduce Professor David Rosen one of the Godfathers of 3D printing and I want to give you a short overview about his bio David Rosen is a principal research scientist at The Institute for high performance Computing and the Singapore Institute for Manufacturing Technologies both are AAR in institutes in Singapore he was a professor in the school of mechanical engineering at the Georgia Institute of technology for many years additionally he held faculty and research positions at the Singapore University of Technology and design who received his PhD at the University of Massachusetts in mechanical engineering his research interests include computer AED design additive manufacturing and design methodology with a special interest in designed for additive manufacturing he’s a fellow fellow of SM asme also he’s the recipient of the 2013 free solid free from fabrication Sy Symposium and more other more Awards and the standards Community to chairs the asmf 42 SubCom committee on design for manufacturing fortive manufacturing so Professor Ros I’m very exciting for your presentation please start all right thanks thank you very much for that kind introduction um really thank uh the uh the design conference organizers and the design for additive manufacturing special interest group for inviting me to come back to Croatia and duik and uh have the honor of giving one of the one of the keynote talks um right so as as uh professor wock said um right I’m uh actually in Singapore uh I’ll get to that in a minute um and and yes spent most of my career as a mechanical engineering professor at Georgia Tech so a little bit of background on on what is this Singapore AAR thing so AAR is the agency for science technology and research um it’s basically uh the National Labs of Singapore um so it’s very broad science and engineering research Council biomedical research Council um and just to give you a little perspective there’s about 5 a half million people in Singapore it’s a fairly small island and there’s about 4500 4,500 technical people that work at Asar okay so um in Singapore uh they they do take research very very seriously and there’s lots of lots of support I’m part of two of the 18 institutes um in AAR uh ihpc and simtech uh and there’s uh roughly 450 or so uh technical people in in each of those um right so um what I’ll talk about today design for additive manufacturing uh it’s great to see um several sessions here at the conference on design for additive um last time I attended uh physically the design conference in 2018 I’m not sure that there were any um so uh uh really good uh growth in in interest in this topic uh the other topic that’s really grown a lot here at the conference is AI and large language models but I will not mention either of those topics in the rest of my talk um yeah so we’ll we’ll uh talk about uh design for additive give a bit of an introduction um we got to expand that to the process chain um and then um I want to tie a lot of this additive design for additive stuff to to sustainability that’s one of the themes of the of the conference um and then uh time permitting I’ll say a few words about product architecture design and 4D printing so but just to provide a a good foundation for everyone right additive manufacturing or 3D printing um represents a class of seven categories of of processes they’re all listed here I won’t go through them in in in detail but they’re all uh based upon the principle of basically layerwise uh adding and processing material to build up parts okay um they they all share that kind of character istic they vary in terms of the material type um how the material is processed and things like that uh but but you know that broadly that that is a class of processes and just to again provide a little bit more uh of a of a grounding I’ve got videos of three different process processes here metal poter bed Fusion up there and let me see if I can start these other guys um metal directed energy deposition is up here using essentially a welding head a welding head on a robot arm and then uh what many of you know of as 3D printing uh or Stratus’s fdm um is the uh U deposition of of uh uh thermoplastic uh polymers um uh filament basically to build up parts okay so laser processing thermal processing of polymer uh and a variety of other kinds of approaches here are used okay um the thing that sets apart design for additive manufacturing from design for manufacturing is basically There’s an opportunity to really make use of the unique characteristics of additive Manufacturing in a way that’s not so apparent with conventional manufacturing processes I’ll say a little bit more about that so my definition of design for additive is to try to maximize product performance through the synthesis of shapes and sizes and material uh composition and and micr structures and things like that really take advantage of the unique capabilities of additive and yes we have to deal with the limitations of the processes but let’s let’s really emphasize what the opportunities are what are the unique characteristics of additive well they’re listed here shape complexity is the most obvious one uh if you’re laser processing the material you know the laser does doesn’t care how complicated the part cross-section is it’ll draw it uh likewise if you’re extruding thermoplastic filament you can extrude it in virtually any shape that you want material complexity um a lot of these processes will support multimaterial uh processing uh so Parts can be made of more than one material um and we can also functionally grade materials or or mechanical properties hierarchical complexity basically means um features can have features so we can texture we we can put texture on on surfaces or we can you know basically have um lattice structures composed of lattice structures and things like that and then functional complexity is the idea of building mechanisms or working devices right in in the vat or in in the machine um illustrated by this example which is a the elevator in a stereo lithography machine that was made in a stereo lithography machine where there’s about um six or seven different metal components that were inserted into the vat in the liquid resin vat um and uh the rest of the structure was built around them plus there are some kinematic joints here um so the elevator slides up and down on a couple of shafts um and there’s other stuff we built in there but the the point is simply that you can get working mechanisms if you can get the material out of the joints and support structure out of the joints and things like that um you can also embed in in some cases Motors actuators uh printed circuit boards and things like that right into into the machine and build around them to make functional devices all right um people have been really creative about taking advantage of these unique capabilities to do a really amazing things I’ve got a mix of um you know technical artifacts here as as well as uh some other non non technical things like this uh but you know the fashion industry jewelry people have been amazingly creative in in uh in what what they’ve done um the uh football American football helmet shown over here is a really good example of taking advantage of uh shape complexity capability to make um Custom Design Parts uh this is a a spinal implant from Striker uh again taking advantage of shape complexity capability uh hearing aid shells invisaline aligners custom designed devices um where you know a million of those uh invisible aligners will be produced per month right you can’t you can’t do that using other manufacturing processes so if we think uh a bit broadly and and try to collect everything together um we we can come to this distinction again between conventional design for manufacturing and design for additive um and so in conventional design for manufacturing what that usually means is let’s understand all the limitations of the manufacturing process and figure out how to design around them and in that kind of respect what designers are doing is is really tweaking in for the most part uh part details all right uh designing for injection molding what draft angle should I use what radius should I use on on Sharp Corners to to round the corners things like that um so design gu guidelines along those uh along those lines do this don’t do that kind of kind of design rules and then um there’s also feature U dimensioning sorts of uh sorts of design guidance so in other words if you’re going to you want to design snap fits these are the kind of Dimensions that you should use again Focus mostly on the design details right that’s what I call restrictive design for manufacturing or design for additive manufacturing the opportunistic uh designed for additive is is what I think is much more interesting and is really the distinguishing characteristic here um because we have you know shape complexity material complexity functional complexity Etc there’s a lot of new things that we can do and really the the the challenge for the designer is to figure out how to take advantage of these unique capabilities to solve their problem in in in ways that haven’t been explored before right I use this uh fuel manifold example from Olaf deagle as an example you you don’t get that design by tweaking the details on your conventional let me gun drill from a block of metal kind of approach to a a fuel manifold right this is a clean sheet design um you got to think in terms of Designing for additive to get that sort of a result okay um in terms of the uh design opportunities we can kind of categorize them as complex geometry custom geometry multiple materials and no tooling and there’s a number of consequences for each one of these things um one of the big advantages that a lot of people talk about is part consolidation right so you can replace four or five injection molded components with one additive polymer component or 10 metal parts that are welded and braced together with you know one metal powder bed Fusion parts things like that um right and that’s that’s really uh important but there’s a lot of other uh advantages here and you know when we think about par consolidation you’re eliminating tooling you don’t have to design tools and fabricate tools like injection mold uh you don’t have uh assembly operations either you don’t have to worry about assembly tooling right then if you are are really effective the performance of your device your integrated device can be a lot better than those U uh you know modules or or components that are built of uh uh several different um conventionally manufactured components so and since we don’t have you know really no tooling is required lot sizes of one are possible short lead times again you don’t design and manufacture tooling but that also enables you to do distributed manufacturing you’re not reliant on a central facility where you’ve invested all that tooling um so you can do manufacturing locally on street corners and things like that all right um there’s a lot of things I could have talked about uh a lot of good research a lot of good uh results but let me let me move on and just say that design for the additive process itself is necessary but it’s not sufficient because most production Parts um are not the result of one manufacturing process in fact if you look at metal uh powder bed Fusion or or metal uh additive Manufacturing in general there’s a lot of additional steps so uh you really have to design for the entire manufacturing process chain because your end result is the sum of all of these different pieces right so metal additive um you typically you do a heat treatment of some kind you’ve got to uh remove support structure you probably want to do some overall finishing or at least finished Machining of your important surfaces and things like that and so the structure of that process chain is important you know what processes are in it the sequencing is important as well uh because there’s implications for changing the uh changing the orders here if you remove support structure before you heat treat your parts probably going to deform a lot if you heat treat right on the build plate without removing supports you’re probably going to maintain um the desired shape a lot a lot longer do that stress relief things like that remove residual stresses get a better result the point simply is that you’ve got to design the entire process chain and the part they all have to be compatible that that’s a lot of work but you also have incredible um design freedoms in each step along the way okay uh just to illustrate that this is a a project uh that was actually done in one of my graduate classes at Georgia Tech a few years ago uh to redesign a bike stem the thing that that holds the handlebars onto the frame we’ll assume that this is ti64 uh we have some loading conditions and um you know the students did generative design using Fusion 360 and uh generated uh that optimized shape that’s not the final design there’s still a lot more work that had to be done that’s the final design okay and uh they did a really good job of going through lots of details so they did the opportunistic design right the generative design and then they did a lot of really good restrictive uh dfam um as well I won’t go through all the details here um a big part of what they did is they said all right we’re we’re designing this lightweight stiff bike stem we’re going to assume production manufacturing and what that means is we want to make as many parts in the build chamber as possible so let’s Orient the parts vertically so we can put a lot in the bill chamber or in in the in the putter bed um and then but if we do that that has implications on the part design okay so what we don’t want to do is in the lattice structure we don’t want support structures you know holding each of these little struts in place so all of those struts have to be self-supporting um so all the struts had to be tweaked a little bit um rounds were added uh everywhere things like that um and then they made some other design decisions based upon minimizing support structure so these purple things blue things are are the support structure that’s supporting the overhangs here um and they made some other decisions about using gusset supports in the big cylind cylindrical areas those surfaces had to be machined anyways uh tight surface finish requirements uh because they’re mating surfaces and so all of these things were considered uh these students ALS o knew a lot about Machining so they did detailed Machining uh process planning and simulation and determined uh Machining times and build times and all that so they could estimate overall part costs um you know so they they really did a good job of putting that manufacturing process chain together and designing each and every step along the way okay um this is a uh a type of um well construct here sorry for the animation uh that I call a process chain map it basically relates design requirements to the different steps in the process chain um the green check check marks indicate which process affects which design requirement and so what you want to see is you want to see all green checks on the on the right hand side um and if you don’t uh then that means you’ve got to make some adjustment in your in your uh process chain okay all right so that’s kind of an overview of that idea of design for the additive manufacturing process chain now when we want to tie that to some of the technical design and uh technical design research um we can take a look at the structure of that process chain and say all right for this design problem I have a bunch of technical requirements uh or you know functional requirements I have to meet and then I want the manufacturing processes to be fast uh less expensive but give me a good enough result and so that to me sounds like a multi-objective design optimization problem right and so we can actually use multi-disciplinary design optimization mdo techniques here um to formulate and solve a large comprehensive integrated design problem where we can decompose the overall uh Pro Part process chain design problem into again a functional part design um sub problem powder bed Fusion process design heat treatment process design finish Machining or support removal process design and yeah yeah finished Machining um uh now we can use surrogate models and stuff like that for for each of these but the point is that we can start with this sort of abstract idea of design for the manufacturing process chain and actually apply very good um well-developed design Theory and methodology kind of tools here we’ve done this for a few different examples one is that bike uh that bike stem I’ll just do size optimization not not with the lat structure and stuff like that just to illustrate that we can um explore that design space defined by in this case we we had three objectives um deflection or stiffness build time and then um part weight or or or part volume and then you know explore um all the the different combinations uh of of the implications of those three objectives and because we have three objectives we can draw a tary diagram like this where blue indicates low object overall objective function values red indicates High um and then we can kind of sample the design space here and we find that point a up at the top in that blue area blue it’s supposed to be good right but it’s really an infeasible design and much of the rest of the design space looks like this so the overall or the the I should say the the outside shape is is pretty much constant we uh you know want to minimize deflection maximize stiffness so you know it’s a pretty pretty big cross-section but the overall cross-sections inside vary a lot as we go from for example part C or Point C down to e andf down down here Point simply is you can again start with that overall designed for the manufacturing process chain kind of problem formulation apply mdo methods and then do uh design exploration and optimization from from there okay now onto uh sustainability kind of considerations um so I was fortunate to be part of a group that uh recently published a paper in nature sustainability on a vision for sustainable additive manufacturing um a great group of co-authors here and I like a special shout out to our fearless leader Serena who really really drove uh the uh development of this of this paper and the and the development of the idea so thank you Serena all right um all right so some of the ideas here I I’ll go through just a set of bullet items um that are sort of common statements about additive manufacturing and sustainability some are supportable and some are not quite uh so first one is am eliminates manufacturing waste am reduces the carbon footprint of parts manufacturer um am eliminates transportation of parts and supply chains am can make use of recycled biobased or biodegradable materials am enables lightweight Parts am enables significant part count reduction that part consolidation I talked about earlier no tooling fewer manufacturing and assembly operations and finally am enables part repair and refurbishment okay all right um some of those are again are true statements and some are well maybe fudged a little bit so the top three um there should be an asterisk after that saying well sometimes right and I I’ll go through a couple of these so um there have been some really detailed LCA life cycle assessment studies of additive manufactured parts and this is a a chart showing a particular set of examples that are polymer Parts um I won’t go through all the details here but but what you see in the middle Mex it’s material Extrusion or 3D printing one 2 3 4 with two different materials for the same process different materials maybe different printers the energy usage is completely different and and in fact this is really unacceptable there there’s no reason a machine a material Extrusion machine should use that much energy um but you know if you if you just take a look at you know reduces carbon footprint right well yeah no not not in all cases right another kind of example um and and this is for for metal Parts here carbon footprint per kilogram of material processed um is actually maybe not such a good measure um but again highly variable uh casting Extrusion roll forming wire drawing conventional processes you know the bars aren’t so long we start going down here to metal additive manufacturing and uh we we see that well no you know the carbon footprint per kilogram of material process is actually really significant um and and in large part that’s because the lasers that are used in these machines are not very efficient um back when I started in the mid 90s lasers were 1 to 2% efficient in terms of power out versus Power in now they’re 25% huge Improvement in Laser Technology uh but still maybe not enough uh the big bar here is for aluminum aluminum is a real shiny material lasers and you know don’t don’t couple well with aluminum powder um the other thing to consider is powder is incredibly energy intensive to produce so atomizers you know melt and then vaporize essentially uh metal uh just think about the process here right you’re casting large ingots of of metal you’re then shipping them to um a facility that has atomizers you’re remelting all that metal and then generating powder with it uh and then capturing it and saving it and it’s just the whole process doesn’t make a lot of sense but regardless now when we look at the real positive side and some of the really Creative Solutions that people have developed I really like this example of a solar powered sand printer um this is a uh a master student at the Royal College of Art in London who came up with this idea of of using you know solar power so solar power collector powder bed Fusion so this is a vat of of a sand powder and um it takes the the the solar energy makes a beam out of it and then rasters the beam in the in the top uh uh layer of the of the sand bed to then produce essentially a glass glass part okay very low carbon footprint here right other people have been really creative about material development so uh we see salt shakers made from Salt up here um this uh filament is is actually made from wine or actually grape skins um this this uh sample over here was 3D printed at um uh Singapore University of Technology and design it’s composed of cellulos and and kiten um so biobased biodegradable uh sort of uh sort of material and that really is you know about what 5 m tall so you know very good uh material so really good opportunities for developing new much more sustainable kinds of materials um another one of the bullet items there was am can be used for repair refurbishment things like that well directed energy deposition processes are um used probably more for repair than they are for part fabrication uh this just illustrates a few different examples of depositing a millimeter or two of metal material onto a worn um uh a part of various kinds you see shaft applications here or um uh a bladed disc kind of application as well all right um so in in our paper we provide a series of of statements or uh proposals for for how am can be be made more sustainable and again like a lot of things if you try to tweak the machines or the processes of the materials a little bit you’re really not going to make big changes but if you think more systematically and more systemically um you you can can make really really big impacts here so say yeah you know look for opportunities to design for part repair design for upgradeability refurbishment remanufacturing things like that look for opportunities to not use conventional high carbon footprint sort of materials but uh opportunities like like I just showed with biodegradable or biobased sorts of materials um said designed for recycling and again um always designed to take advantage of am’s unique capabilities okay we uh provide this overall sort of idea about an ideal scenario okay that covers everything from the again the raw materials whether it’s biobased or biodegradable or coming up with a new way I’ll get out of the way you can take pictures um uh coming up with a new way to to make metal powder would would have a huge impact as well uh printer design part design how all those integrate together um with the uh the process design and the actual you know 3D printers themselves how energy efficient they are what their characteristics are and then from the printers into the production system overall and the part and product life cycle so so again the scenario is trying to tie all that together uh remember that one of the bullet items was hey am eliminates part Transportation costs all of the trucks in that schematic indicate something is being transported so again not not not exactly um but uh but again we we have the scenario here uh you can take a look and study it further okay I am probably running out of time a little bit I don’t know how we doing on time okay no one cares great I’m going to keep talking um now I’ve got two more topics here I’ll go through them fairly quickly so I’ve said repeatedly we want to take advantage of the unique capabilities and and uh really what what’s key there um is to look for changes in part design and product design that can have a really huge impact and to me the the thing that really has a huge impact is product architecture design that’s indicated by this uh ebike this motorcycle here but but first a real extreme example now GE um and in particular GE Aerospace has been of the leaders in um designing for metal uh uh additive manufacturing and uh as a as a demonstration they redesigned this turbo prop engine there’s a conventional design and here’s their additive manufacturer design they claim to go from about 850 Parts down to 11 okay that’s an order of magnitude in in part reduction and so this isn’t just uh you know applying the Boost roid doers designed for assembly guidance of well you know if two parts are connected uh and they’re the same material and they’re not moving relative to one another you can you can maybe consolidate them you you you can’t just apply that and then get an order of magnitude decrease in part count you’ve got to really do clean sheet design and and that’s what GE did all right so they not only you know can really greatly simplify the factory floor they get better performance um and uh you know uh well yeah better better performance and probably longer life things like that of course Central to product architecture uh design is this idea of I modular am I integral where on that Spectrum are we um and and you know there there’s a role for for both um but I would argue that in terms of applying additive manufacturing if you have a modular architecture each of your modules could be highly integrated and very efficient from a part comp perspective a little bit more about this um 3D printed motorcycle so uh this is an ebike electric uh motor powered uh motorcycle um couple things that are really novel about this um it consists of 15 3D printed parts and that includes the tires Wheels seat frame everything well everything except the electric motor the battery and the uh the contr control Electronics um but but everything else is 3D printed and when I say 3D printed I mean po thermoplastic material Extrusion kind of 3D printed okay one thing to notice about this this is a this is a hinge that allows you to steer okay it’s not the spring it’s not a spring that’s part of the suspension in fact there are no suspension components in here whatsoever okay but you get a suspension function because you have elaser wheels you’ve got honeycomb structures for the for elaser tires honeycomb structures in the wheels um you have this flexible bumper it’s basically a honeycomb um uh structure that will Flex underneath the seat and the seat is elaser as well plus the whole frame is um you know it’s ABS a carbon fiber reinforced ABS um so it does have some Flex as well but if you can eliminate entire subsystems like expension subsystems you can get you know you’re you’re changing the product architecture radically and you can get tremendous um part consolidation all right now from an engineering research or design research perspective you know yeah we can go back look at the functions look at you know the relationship between function and form and where do modules come from and and and then look for opportunities for um uh function sharing function integration and and things like that uh so we we did just that uh listed the functions out listed the different components um and uh I won’t go through all the details here but but again um let me go yeah so suspension gets replaced um and you know we get some function sharing uh the overall architecture there’s no separate handlebar from the fork from the steering mechanism they actually did left and right sides so the left handlebar is connected to the left Fork right hand okay and there’s a hinge in in between so um some novel design components and then of course going from a gas powered um motor to uh to an electric motor you get some function integration don’t need a u a separate transmission and things like that so you know tremendous differences in architectures between conventional uh and uh this specially designed ebike okay and then more broadly okay got it more broadly um you know we can look at a whole set of Industry examples um interestingly they’re all in the Transportation uh domain but but that’s okay so again an aerospace the ebike and then a couple of you know car and mini buus sort of examples um uh and turns out that these three are all thermoplastic material extruded designs and then the GE motor uh engine is uh metal powder bid Fusion okay in each case uh essentially the products resulted from clean sheet design novel product architectures novel approaches to design and a lot of good insights in additive manufacturing that they could take advantage of all right now a few words about 4D printing um so 4D printing is 3D printing with the fourth dimension being time so you have a shape change um uh over over time so the tech box over there was designed such that different joints were actuated at different times and then this example one of my favorite examples Christina thanks for sharing it even though you know you didn’t know you shared it with me um this is a a solar panel deployment mechanism where the scissor mechanisms along the outside are shape memory polymer things that that actuate to go from a folded to a extended configuration and that opens up an origami uh interior where the actual solar panels are mounted um so just two two different examples sort of two ends of the Spectrum in terms of complexity but this is the idea um if we go back to this one you know the Box started out as as print you know it’s printed flat okay right so you could print that flat you could print out a thousand of them ship them all stacked up and then where they are needed you put them in or you you heat them up it actuates the shape memory effect effect and they fold up into the desired shape right uh solar panel those go on satellites right you need something very very compact to launch and then you want it to deploy so it it’s that sort of idea so I’ve talked a lot about product architecture design and part consolidation and so additive manufacturing had a huge impact on um you know this idea of Designing structures or structural components right with 4D printing with you know utilizing the shape memory effect we’re we’re actually designing actuators into our structure and so if you think about conventional mechatronic devices right there’s Servo Motors and bearings and shafts and bushings and uh set screws and and lots of different components if we can replace those with shape memory hinges we have a tremendous simplification of the design tremendous part consolidation so long term the future is 4D printing is going to do for megatronic devices what 3D printing has done for structures that’s my my prediction you know take it with a grain of salt if you want but we’ll see if it comes true um and then finally um when you look at the 4D printing or the the the shape memory device uh literature you see very simple components for the most part we developed this new material we’re going to print a strip of it and look at folds right uh Christina’s example with that with that uh origami uh solar panel is is one of the notable exceptions but the point is there’s been a whole bunch of these simple components that have been designed and engineered we know how they behave right if we had an overall design synthesis capability that said hey here’s my problem specification and in terms of start with that shape give me that shape eventually how many different ways how many different ways of combining these components might you come up with that could fulfill that requirement right so one of the uh topics that we’re working on um at AAR in Singapore is this idea of a general design method for 4D printing for morphing and Deployable structures that that’s based on this idea of a design library and matching that with problem specification so we’ll see how that works uh yeah I forgot okay all right so we need this thing to bend okay let’s use a bending cylinder we need that um that that stretching or that extension let’s use a scissor mechanism uh to then uh go uh interrogate an entire workspace in a robot arm sort of sort of fashion um okay to wrap up here uh I wanted to introduce the whole idea of design for additive manufacturing contrast that with design for manufacturing emphasize again that we have some unique capabilities and the challenge to achieve the maximum benefit is to take advantage of those unique capabilities but do remember we got a design for the entire process chain not just one process um we took a look at you know kind of the pros and cons and and good and bad characteristics of am relative to sustainability and then I had a few words about product architecture design and 4D printing with that thank you for your attention I I hope you’ve learned something and a final note and a Shameless plug um I understand that this is a really good resource if you want to learn more thank you very much thank you very much for that wonderful presentation I’m sure there are some questions we take time for some questions okay who’s got a question please no questions could not be come on you you know professors like questions and don’t don’t let Serena what’s yeah Serena right okay thank you for this wonderful overview for the Insight you provide us I have maybe a tricky question for you uh is there something you have not yet seen in additive and you would like to see developed as a design from a design point of view is there something missing from your point of view yeah I’ll give you two quick answers to that one is I want someone to come up with metal powder production that doesn’t involve the the conventional you know metal uh fabrication uh workflow because again it’s highly highly inefficient but the other thing I want to highlight is let’s assume that we do solve that problem um I mean just think about fabricating an engine block using a laser that’s 100 microns in diameter I mean you can scan as fast as you want it’s still going to take you days and days to fabricate that and at 50 to 100 EUR per hour that’s more money than I have in my pocket okay that’s a that’s really expensive and if you’re so why is an additive used in the automotive industry but it is in medical and Aerospace it’s because those Industries are not nearly as cost sensitive so what we need is new technologies that allow us to fabricate cross-sections at a time in metal right so we got to get away from you know one laser scanning or 10 laser scanning we got to get to a million beams or or something equivalent to that to go to do what stereolithography did from laser scanning to DLP Mass projection right we need the same kind of technology for for uh for metal additive and that’ll have a huge impact thank you Christina thanks for the nice presentation uh of course I have a question on the last Point 40 printing what do you think are the biggest challenges to be able to reach um the goal that you said of of replacing standard things like hinges with a 40 printed hinge yeah yeah that that’s a that’s a great question um if I have the chance I’m going to turn around and ask you the same thing because you may have more insights but um I I would say that the materials uh really need to be greatly improved yes we get the shape change but the the forces and and the torqus that are being generated are very small so you know can you really launch that solar panel deployment mechanism and have it operate and H you know maybe maybe not not so much so yeah I think materials is really really key here um and and then you know the the other again I talked about a design method here I I I really think that we have a a tremendous opportunity to come up with new ways of synthesizing devices that span from you know simple components to origami kind of structures to compliant mechanisms and a Continuum among those okay thank you thank you Professor for the very nice talk and uh variety of things which are going on in this area I was particularly interested in the 4D printing space again connected to the previous question as well in one of your slides you had hinted that we could use magnetic fields and some mechanisms for triggering thing which is interesting about megatronics is you have electronic control can you spend share a little more about What mechanisms can we use for uh controlling uh structures like this sure sure yeah um so kind of a shorthand 40 printing is shape memory effect well we don’t have to limit ourselves to just shape memory we have residual addesses we have shape memory effect plus if we add electrically uh U or magnetically active particles or things like that into the material we can use additional fields to try to you know get get you know uh improved uh performance so again there there’s a whole spectrum of technologies that that that we could bring to bear um and and you want to add those additives to get better mechanical properties get faster actuation more reputable actuation um more for things like that so so again um now we also have a controls issue here right so so um right now I I’ll just contrast that with the examples that I showed we’re we we put the entire device into a vat of hot water and the heat in the hot water actuated the uh the shape change um we really want to be able to locally control the the actuation um and control it uh and maybe build sensors in there as well so we can do feedback or Clos lip control of of all of this um when we start adding uh electrically and magnetically stimulated well we’ve just really complicated the whole device now and so there’s there’s a trade-off there uh so these are all sort of trade-offs and considerations that really have to be explored but plenty of opportunity for novel design ideas to take advantage of the best aspects of the Technologies uh but achieve good trade-offs among the the competing objectives all right okay I think everything was absolutely clear so again thank you very very much for the wonderful presentation thank you and now now we have coffee break until a quarter 3 and we all meet here at halfast 5 for the closing ceremony thank you very much thank you