2019 DXA Grant Report (Draft)

Research in Additive Manufacturing Romรกn Falcรณn

Introduction

This text is the third installment of the research grant program offered by DXA Studio, which annually awards an individual staff member the opportunity to conduct a month-long period of investigation. Those researchers are tasked with exploring topics that are considered relevant to the collective knowledge base and future growth of DXA Studio.

With this agenda in mind, the following text centers on emerging trends in additive manufacturing (consider 3D printing or AM as interchangeable terms) combined with an analysis of parametric workflows that complement, support or optimize exploratory fabrication methods. An interest in 1 to 1 scale building components served as the initial trajectory and this remained consistent throughout the documented research period. With an emphasis on structure, enclosure, elements applied and/or integrated serving to enhance energy performance and lastly ornament, this text profiles real projects that pertain to for profit companies or research institutions.

As a research topic, additive manufacturing proves to be quite vast and varied. It is a young field being propelled by rapid technological advancements. Paul de Ruiter, who leads the LAMA lab TU Delft School of Architecture, observes that in order to keep up with AM, one has to monitor the field consistently and remain familiar with current trends and breakthroughs. Yet the approaches and intentions are quite varied, so for research purposes, it helps to set up some basic parameters in order to distill this information matrix and form a coherent narrative. For example, there are publications that focus solely on exploration occurring at the university level. Andrei Gheorghe expands on this theme in his adapted dissertation titled DADA (digital architectural design assertion), which not only catalogs a series of design studios emphasizing workflow with equal significance to final product, but challenges universally perceived traditions embedded within a generalist’s view of architectural pedagogy1.

Another approach would entail looking beyond education. In The Blindspot Initiative (Design resistance and alternative modes of practice), Jose Sanchez profiles a group of architects that have, like the title suggests, expanded their considered range of typology and repositioned their approach to design and fabrication. In many cases, this agenda arrives at a discovered dialog with 3D printing and the output shifts from project to product. The results may fall into the category of industrial design or shift into the realm of fine arts, and this only serves to illustrate the potential for architects to reinvent the nature of their profession as well as become players in adjacent industries. Whether the end product be jewelry, sculpture or automotive design, the underlying theme is agency, removal of the subcontractor or any procedural negotiations required to complete the digital to tactile workflow2.

The abovementioned topics are no doubt compelling and essential to the

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overarching narrative of emerging trends in additive manufacturing. The nature of this text, however, establishes its relevancy with regards to a conventional practice operating as a business, designing enclosed, inhabitable spaces. This is not to say that academia or niche companies will be ignored entirely. Rather, as a constraint for the investigation, projects featured here will offer findings that would interest any architecture studio that is both exploratory and profit driven.

The most fundamental question driving the research is as follows: Considering the increasingly familiar means of complex form generation via robust 3D software packages, is additive manufacturing a viable option to realize such geometry within the established context of the AEC (Architecture, Engineering and Construction) industry? Within this text, the equation of cost as a function of time and material becomes a recurring theme and forms the initial basis for evaluating 3D printing as an alternative to sourcing standardized components.

It deserves mention that the inspiration for this research, as cited initially in the written grant proposal, stems from the experience and involvement with DXA Studio’s conceptual pedestrian bridge project. “The Midtown Viaduct” is the 2019 winning entry for an open competition hosted by Metals in Construction Magazine. This scheme showcases an urban pathway that connects the southwest corner of the new Moynihan Station with a section of the Highline known as “The Spur”. Granting much appeal is the sinuous quality of the bridge’s form, the end result of many gestural iterations created within 3D software and utilizing a parametric workflow. Each iteration was tested and evaluated as a graphic overlay (in plan view) onto its urban site, which yielded additional proposals regarding program, landscaping and material. Emerging from an array of topics was the question of structural definition as a means to bridge the conceptual gap between digital form and the proposed fabrication method. Structural engineer Scot Hughes volunteered his consultation and

3 THE MIDTOWN VIADUCT 9TH AVENUE BRIDGE

THE BRIDGE: STRUCTURAL DESIGN

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these group discussions eventually established a narrative deemed appropriate for the competition brief. Utilizing CNC water jet cutting technology, the bridge structure would STRUCTURAL be divided into a series of 40-foot modules, sized for_______ FABRICATION CONCEPT maximum trucking mobility. By design, these modules are further subdivided into 10-foot spans, each defined in section by a dominant CNC cut steel rib and joined perpendicularly by smaller steel sections often running in the direction of travel.

The structure consists of transverse ring ribs shaped according to the cross-section of the pathway and spaced approximately every 10 feet at the longer, more linear paths. The spacing decreases at areas of transition, such as changes in direction or at columns. Longitudinal, linear ribs span between the transverse rings. The bridge takes advantage of the depth created by the over-arching express footpath

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designated for commuters. This added depth along with the interconnecting vertical elements create a very deep and efficient truss. The rib components are cut using a large format CNC water jet machine from stock steel plate. Where necessary, the ribs are split into manageable sections for cutting and then welded together. The longitudinal ribs are also cut from stock plate to match the shape of the pathway.

Each 10-foot section forms a component of the overall structural frame that is pre-assembled in the fabrication shop in 30 to 50 foot long sections so that they can be readily shipped to the site and erected.

It is safe to say that this structural scheme, based on fabrication techniques well-understood within the AEC industry, resonated with the competition judges. Furthermore, the success of this competition entry suggests that formal expression as an isolated endeavor may prove conceptually lacking without a realistic approach to component fabrication and assembly. While digital tools offer many paths to explore, test and develop form, the real challenge emerges when a narrative for construction must accompany a given propos-

t ornamental expression: Penn Station Interior Concourse 1910 street

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Structural Framing: The Statue of Liberty 1881

Water jet steel: ‘ZEPP’ ribs at Zahner HQ

Waterjet fabrication in progress street

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al. Thus, the parametric process, when negotiating with sinuous forms and surfaces, will always be confronted with the realities of subdivision and 2D planar retooling. This becomes an inevitable steppingstone toward achieving a physical, tactile representation of the original design.

There was, however, a brief period early on during these schematic discussions regarding structure and fabrication, where the emergent field of additive manufacturing was considered. The team focused its attention toward an online article claiming to feature the world’s first 3D printed steel bridge, the combined efforts of fabrication startup MX3D and architecture studio Joris Laarman Lab, both based in Amsterdam3. Beginning with form, both schemes are characteristically sinuous steel structures. Programmatically similar, they were designed to elevate and carry pedestrian traffic. What became of particular interest was the fact that this approach to additive manufacturing could produce results that bore such close resemblance to the original digital model. Evidenced by high precision geometry and fine linear striations, (textural artifacts tracing the movement of welding robotic arm), the work of MX3D confirmed that a direct translation from digital model to printed from at 1:1 scale was now a possibility. It should not be overlooked that structural performance is of primary interest, so what this project really presents is an elegant intersection of design and engineering.

It is difficult to identify a cultural inflection point regarding a shift in the way architects who utilize digital tools consider material output. Yet as advancements in 3D printing begin to intersect with computational design, it is reasonable to consider that at some point in the future, this dimensional downshift, or 2D retooling, may soon prove less efficient than the more exacting alternative of additive manufacturing. What significance, if any, does this emerging technology bear on the outlook of an architecture studio increasingly interested in complex geometry via parametric process? It is this line of questioning that prompted a research initiative. The objective was to open communication with companies and research groups that specialize in additive manufacturing, to gain their perspective the field’s technical and market trajectory. Again, the interest is 1 to 1 scale building components and how the means of their realization may influence an evolution of the AEC industry.

At the time of writing, it seems that when searching for compelling articles regarding additive manufacturing, a large percentage of web traffic get directed to companies located in The Netherlands. For this reason, when given the opportunity to plan a research trip, Amsterdam became an initial point of interest. As a result, during the first half of September 2019, meetings were scheduled with the following Dutch companies/ institutions: MX3D, Aectual/ DUS Architects and the Sandbox research department at TU Delft. Each meeting was approached with a specific agenda and thus yielded distinct findings.

The following text serves to document the most important aspects of each meeting with the intent to provide an objective analysis of additive manufacturing as it relates to the design studio.

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MX3D

As mentioned previously, the work of MX3D was the catalyst for this research project. Thematically, there was a perceived overlap between the nature of their work and DXA’s Midtown Viaduct. Thus, it was assumed that this meeting would be the most significant of the trip. A visit to the company’s website will reveal professional photos showcasing a lofty, naturally lit warehouse with robotic arms and their printed steel forms scattered throughout the space.

Featured most prominently among them is the widely publicized pedestrian bridge. Recalling the January 2019 issue of Detail Magazine, a featured article provides insight to the bridge design and the company’s process: The bridge, which is 12 meters long, was manufactured at Amsterdam’s start-up MX3D, which specializes in a technique known as wire arc additive manufacturing. The company combines the necessary industrial robot with a welding machine that can process most weldable alloys. Metal welding wires are used as raw material. For the most part, the bridge deck consists of components around 1 m in length; these are individually extruded and subsequently welded together. However, the robot also made some longer sections, for which it was mounted directly onto the bridge deck.1 Having established an email correspondence with CEO Gijs van der Velden, it was understood that DXA Studio was interested in printing a portion of its bridge design so that it may be featured as part of an exhibit in the 2020

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Venice Biennale. For the sake of this research, however, it was important also to learn as much about the company as possible.

The experience of visiting this office creates a stark contrast to the impression gained through the company’s website. It turns out MX3D had just relocated away from that industrial neighborhood located on the North side of the IJ, to an area that houses a series of non-descript low rise office buildings, far removed from Amsterdam proper. The ground floor office lobby features a visitor’s area to the right of the entrance. In the center a series of chairs surrounded on three sides by dark grey partitions. The chairs face forward, oriented to two mounted flat screen televisions. The left screen displayed a still image of the old MX3D warehouse exterior and the right, a young woman riding a 3D printed steel bicycle. Along the adjacent wall was a series of metal objects which varied in shape and size. These were 3D printed steel artifacts that showcased the range of output made possible by the company’s robotic arms, products of industry leader ABB2. Among these objects, what catches the eye immediately are two wall mounted bicycles. Both were fashioned as single gear racers. On the left was a solid body frame with apparent surface striations. Its rough texture contrasted with the fluid, industrial quality that one normally associates with contemporary bicycles. The bicycle on the right featured a frame that could be described as an open gridshell. Similar in effect to subdividing a NURBS surface within a given 3D software package, this appeared to be a printed wireframe of each combined face. The two bicycles are significant as they identify and illustrate two distinct printing methods utilized by MX3D, the continuous print and the dot print.

Let’s establish that the terms print and weld will be used interchangeably with regards to MX3D. As Gijs explained, the robotic arm behaves as a programmed welder an any metal alloy available in spool format can be printed in this manner. Yet unlike traditional welding, no preexisting objects are being joined together. This additive process depends solely on the given spool, the source of all printed output.

The Continuous Method

This type of print, exemplified by the solid bicycle frame, recalls the functionality of any FDM printing, common to most consumer-based 3D printer (i.e Makerbot, Ultimaker). Naturally, the process begins at the printer’s base plate.

The nozzle moves freely in the x, y-directions and outputs all contours that run parallel to said base. The nozzle then moves up in the z-direction to repeat the process, gradually building upon itself.

The continuous method offers a textural aesthetic to its printed surfaces, because the movements of the robotic arm are evidenced by the apparent contoured texture. Yet the thickness of these lines may vary depending on the print settings. Other objects in this visitor’s area showed striations that ranged from 5mm to 8mm. A sculptural bronze propeller welded to a flat base sat at

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the opposite end of the room. On one side, it showcased striations on the finer end of the spectrum while the opposing side featured a smooth reflective finish. All this to say some of these objects underwent a finishing stage, where one manually grinded down the surface, converting the rough print into a finessed sculpture. This post print phase required a level of craftsmanship, an aspect of steel printing that had not been anticipated.

The Dot Print Method

The dot print, exemplified by the gridshell bicycle frame, could be described as a point cloud made tactile. With this method, the robotic arm prints a single +/- 8mm “dot� of metal and moves away to repeat the process in other locations. Allowing for sufficient cooling time, the arm returns to the initial coordinates and adds another dot. Building on itself, the robot is additively welding in open space, printing a multitude of vertices with a surface texture resembling that of a millipede. By their own admission, the grid shell bicycle did not represent the ideal print quality that MX3D strives to create. Seemingly crude and unfinished, however, it was revealed that this gridshell iteration was the work for student interns from TU Delft. Nevertheless, certain portions were identified to discuss how a dot print can get sloppy. If a recently welded area is not given time to cool, there will be distortion in the model. Areas that show this condition have a melted quality, where some dots appear oversized and others seem to have morphed together, bubbling over and morphing with other portions of the frame.

A cleaner example of the dot print stood at the opposite end of the open office. This was a gridshell column, whose digital 3D model may have been created with a simple spline-revolve operation. From its splayed base, the column tapers then expands towards its center. The base and capital appear to mirror each other, suggesting symmetry. With any welding operation, however, the reality is that nothing is truly symmetrical. Yet the column structure created an opportunity to showcase better craft because it could naturally build upon itself, moving upward in the z-direction with only subtle variations in the x, y coordinates.

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Limitations

While surveying the gridshell column and the two bicycle frames, certain procedural parameters were revealed. Measured from the horizontal plane, the robotic arm can successfully print from 90 to 45 degrees. A continuous print can extend to a limit of 30 degrees, but overall formal distortions may occur, as gravity will pull on the alloy in its liquid state. As a result, the individual

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striations in this range may appear warped and bloated. On the other hand, the dot print can handle a higher degree of complexity with regards to the input digital model and will successfully perform up to 30 degrees. In some cases, the robotic arm can toggle between dot and continuous settings, but this decision is intertwined with design intent. What remains clear regarding limitations: a purely horizontal, zero-degree print is not possible. To overcome these constraints, it becomes necessary to rethink the orientation of the model. Take a bridge for example. The portions that extend horizontally may have to be rotated 90 degrees so that the robotic can move upward, not outward.

Thus, when viewing any continuous print, consider that the apparent striations were likely once oriented to a flat plane that was parallel to the ground at the time of fabrication.

The tour proceeded in the direction of the open workshop beyond the visitor’s center. The first stop was a small space within a partitioned shipping container. Behind the entry door, there stood a motionless robotic arm. Gijs explained for safety reasons, robotic arm operation should occur within closed quarters. As is the case with the dot print, the movements of the arm are less intuitive. Even though the printing software will display all movements before fabrication commences, technicians within close proximity inherently will risk injury. The enclosed space offers a safety measure, but ventilation is still a necessity. All alloys release fumes when heated and some burn cleaner than others. Thus, the facility requires an open air but sheltered configuration.

Given these considerations regarding safety and enclosed quarters of robot operation, there emerged a disconnect with the images featured on MX3D’s website, where robotic arms are depicted as programmed solitary agents, left to additively manufacture bridge structures in the absence of human technicians. Some images are set within the previous, naturally lit warehouse location. Yet the more compelling settings include canals and rivers, where the robotic arm is shown at the edge of a half-welded bridge of its own creation, suspended over water. Given that MX3D owns a total of eight robots, one has to consider the risk factor, not to mention the power source, software connection and material feed, all missing in these images. It turns out that this company plays by a similar set of rules utilized by most architecture studios.

A closer inspection of the website reveals a clever combination of real printed artifacts nestled between photorealistic renders, all set on a timed slideshow.

One has to commend them on their clever marketing strategy, as it reverberated through publications well known in the AEC industry and beyond.

Amateur photography along with clumsy Instagram posts might dampen the allure this niche practice and it was made clear early on that visitors were to respect their strict “no photos” policy.

Back to the tour. There were no indicators suggesting that MX3D was in the habit of deploying programed robots to operate freely on any given jobsite.

Still, for the sake of the research agenda, it seemed necessary to prompt the questions: What impact could this technology have on the construction

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industry? Is it possible that some day we would see robotic arms on construction sites, doing the work normally assigned to the subcontractor? Gijs explained that the main challenge would be the weather. As for the welding process, wind and precipitation are the worst enemy. Robotic arms are not cheap, so testing their ability to withstand the elements would be a poor way to honor an investment. Furthermore, MX3D still positions itself as a source for fabrication, not a contracting operation. The capacity of their work functions within the parameters of offsite fabrication which later ships to a job site for final assembly. If insitu fabrication were the desired objective, Gijs speculated that a contractor could erect a protective enclosure, i.e. weather-proof tents, which would allow the robots to operate freely. This he concluded would be more for the sake of performance or showmanship, not at all practical.

Considering these constraints and given that the realities of freight operations, Gijs explained how a company like MX3D would accommodate a distant site, a place like New York City for example. The solution, simply put, is to set up shop nearby. They would acquire robotic arms and operate in a warehouse within close proximity. The scale of fabricated components would be constrained by the capacity of the trucking bed. So it seems that any academic speculation oriented towards a revolutionized construction industry via robotic activity would be hard pressed to find supporting evidence at MX3D. Regarding fabrication, it came as a surprise to learn that this approach to additive manufacturing is still very much human dependent. The acclaimed “world’s first 3D printed steel bridge” did not come to fruition through the push of a button. Rather, it was the transformation of a rough continuous print. As that initial article in Detail explained, the finalized form is not a single print, but a series of parts welded together. What the article fails to mention is the fact that these prints were then grinded down by hand for that pristine surface finish that adorns the website.

At the time of writing, the bridge designed by Joris Laarman Lab and fabricated by MX3D has not been installed at its designated canal site in De Wallen. It was last publicly showcased late October 2018 during the Dutch Design Week conference in Eindhoven, Netherlands3. Currently, the bridge is undergoing structural testing at the University of Twente in collaboration with the Imperial College of London4. A full timeline of the bridge project is displayed on MX3D’s website5.

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DUS / Aectual

Similar to the meeting with MX3D, the premise of this meeting was to discuss the prospect of printing a 3D model for the Venice Biennale. An early arrival allowed enough time to survey the expansive concrete lot that contains the singular two-story office of Aectual and Dus. The building itself stands without any particular cladding system, only exposed tar paper and the occasional mounted 3D printed plastic composite samples functioning as rain screen.

It was revealed during the meeting that these samples were experiments intended to inform how they perform as exterior applications. In front of the office stood the well-publicized 3D printed urban cabin1 as well as a singular concrete stair, a sculptural 16 risers on a single run without a landing. Inside, the office is bright and neutral giving way to the ornamental array of more 3D printed samples showcasing a variety of colors, patterns and textures. Experientially, this exemplified an almost seamless transition from company website to company workspace.

Business development manager Andrea van Zwet made the initial introductions and was soon accompanied by co-founder and architect Hans Vermeulen. What ensued was a company presentation in their conference room, led

by Hans. This keynote slideshow told a story or origins, where architecture studio DUS turned to additive manufacturing as a means to ensure precision and quality control of their designed installations. Such a maneuver stemmed from early frustrations with a building industry that failed to accommodate their design intent and thus served as a measure to reclaim a level of control in the building process. The abovementioned printed cabin exemplifies full agency, where the design and fabrication processes are managed by a singular entity. However, lacking basic MEP systems, thermal insulation, waterproofing etc., this cabin qualifies more as an installation rather than building project. That distinction is a bit more blurred in the case of the Europe Building project, where a series of 3D printed plastic benches were seamlessly integrated with a system of applied façade panels of the same material. Designed as a temporary installation, the plastic benches were dismantled and shredded into pellets ready to be 3D printed once again. This highlights one of the main agendas in the work of DUS, to demonstrate that common waste (plastic) can be the singular material source to realize complex geometry. In fact, on their conference room table sat a ceramic bowl filled with these same blue plastic pellets that were sourced from these decommissioned benches and panels. Hans firmly believe that in 10 years, the concept of waste will be passÊ. This is a highly optimistic worldview considering the amount of plastic waste currently floating around in in the Pacific Ocean. Nevertheless, it is this approach towards 100% material recycling that spawned offshoot company Aectual, which as mentioned previously, offices in the same building.

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Aectual has a different business model entirely. It specializes in product and material design through additive manufacturing, earning commissions by creating bespoke products for retail environments. Its signature terrazzo floors

are defined by 3D printed linear patterns working in place of the traditionally utilized metal inlays. Examples of this flooring can be seen at Amsterdam’s Schiphol airport or at the BMW Welt exhibition space in Munich, the latter a collaborative effort with industrial designer Patricia Urquiola. The Nike flag-

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ship store in London features a mesh panel whose construction recalls fabric weave assemblies commonly utilized in running shoes.

At the root of these installations is a high degree of customization, which forms a perfect pairing with the sectors of retail and branding. More relevant to this research, however, is Aectual’s bespoke approach to the design and fabrication of concrete stairs. This starts with the company-designed software package whose settings can be adjusted to the building codes of any local jurisdiction. What follows is the fabrication of precise plastic formwork through large scale 3D printers. In this case, Aectual is not pursuing the solid, but creating the void through which a precast reinforced concrete stair may be formed. After the curing process, the stair is removed and readied for shipment while the PET-based formwork is shredded back into pellet form. This process itself makes a statement about construction waste and optimization made possible through a unique parametric workflow. There is no reason why

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stairs cannot be swapped out for other precast architectural elements i.e. façade panels.

Aectual positions itself as a company that provides the tools for designers to digitally create and in turn realize built form under one roof. The topic of authorship as it relates to design often emerges when these open source digital processes are utilized. When asked if this blurred definition of authorship was bothersome to a company like Aectual, Hans seemed completely unfazed. He agreed the end product must share credit among multiple parties but emphasized that if not for Aectual’s workflow and service, this kind of built form would not be possible.

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TU Delft

“The Sandbox” is the department within TU Delft’s School of Architecture that is dedicated to research in additive manufacturing. Located at the west wing of the ground floor, the lab is home to an array of 3D printers and robotic arms of various sizes and configurations. Students are welcome to use the facility, but departmental policy requires that this use and/ or experimentation is linked to academic research. A closer look at The Sandbox website reveals that there are two distinct labs within this department, Robotic Building1 and LAMA (Laboratory for Additive Manufacturing in Architecture)2. Much of the research taking place at LAMA focusses on 3D printed façade systems. Given that the theme of enclosure was a topic cited initially in this grant proposal, LAMA became a point of interest during the research trip to The Netherlands. Paul de Ruiter heads LAMA and works alongside Dr. Michela Turrin, who continues her own research in additive manufacturing as well as oversees graduate thesis projects. They were both generous enough to lend some time and provided an overview of key projects of interest, both past and present.

Among the handful of research projects overseen by LAMA, one graduate thesis titled The AM Envelope by former student Valeria Piccioni was distinct because the work resulted in a façade panel prototype. Citing concerns about resource consumption attributed to the building industry, additive manufacturing became the means to research, design and create a mono-material solution. Though perhaps obvious to most, it deserves mention that the AM process represents a significant reduction in construction waste. Furthermore, the familiar material sandwich and flashing requirements inherent with exterior wall assemblies are absent from this proposal3. With a multiplicity of functions, the result was a 3D printed panel representing a building envelope system, permitting natural light, achieving optimal thermal performance and rigidity.

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As a guiding principal, all work in LAMA lab negates formal expression that is not rooted in research. In other words, this is not a place where design is evaluated based on aesthetic appeal. Should geometric complexity emerge from its projects, as it often does, the general consensus dictates that these forms are the result of a long investigative process. In the case of The AM Envelope, cellular and lattice structures were identified as natural systems that would serve to generate further investigation into the topics of insulation and structure, respectively. The thesis makes clear that digital tools and parametric workflows were essential for achieving optimized design.

As stated in its introduction chapter, in the subheading titled, Research through design exploration, Piccioni explains: The geometries will be digitally modelled, working in the same parametric environment to have a better control over the relation between design variables and required performances. The parametric environment of Grasshopper plug-in for Rhino will be used. Crystallon is a Grasshopper plug-in that will be used to generate solid cellular structures within a design space.

The assessment of the designs will be done by means of physical testing and digital tools. In particular, digital tools will be used for the optimization of the structure using Topology Optimization and to assess the structural performance of the optimized geometry. Specific design limitations/targets deriving from the AM production will be considered in the optimization process. TO will be performed within the Grasshopper environment.

Plug-ins such as Millipedes will be used. In the preliminary design phase,

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a benchmarking among different tools on speed, robustness, functionality and flexibility will be done to evaluate the best option4.

The AM Envelope demonstrates a nod towards a future building industry that would utilize mono material systems as a means to optimize thermal performance and reduce the number of components that make up a given envelope assembly. Furthermore, the process of sourcing recyclable materials post-demolition is inherently optimized. In the case of the AM envelope, the resulting gyroid system achieves these goals but its porous form alone does not provide a complete solution for a weather tight building enclosure. Piccioni acknowledges the need for additional study and suggests the integration of a thin exterior skin as well as rubber gaskets at panel joints.

The exterior cladding of Snohetta’s SFMOMA is cited as a building skin whose resulting geometrical characteristics are not far off from what would be needed to complete The AM Envelope5.

A separate graduate thesis project titled SPONGE3D references polyhedral structures and blood vessels as an AM solution for thermal performance and full enclosure. Another example of a cellular mono material system, the exterior face of the panel features hollow vertical tubes, through which water may be stored to retain and release heat depending on time of day or year6. One could expand on this vertical tube concept, utilizing those

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voids with more systems i.e. refrigerant lines running to and from remote condenser units or electrical conduit. Of course, the inclusion of any MEP systems would require coordination with forward thinking consultants, a different approach to integrated project delivery. The Centre Pompidou could serve as a precedent for such efforts, but again the distinction here is a single 3D printed module made of recyclable plastic, not a high-tech

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assembly of stainless-steel components sustaining secondary systems articulated with primary colors.

Both research projects nod to a future building industry that favors a reduction of façade assembly components. Granted, the reality of translucent façade panels made of plastic might not possess the same aesthetic appeal that could be obtained by more established practice of unitized panel systems. Yet considering that it is now possible to print structural concrete with carbon fiber reinforcement as well as natural wood products, there are indicators that the range of material options will continue to expand.

Perhaps a complete mono material approach will clash with human affinity for natural materials. Nevertheless, if a design process allows for an initial period of research with an optimization agenda, there could soon be enough supporting evidence to prove such a design approach is economically viable. When this methodology impacts the bottom line, the demonstrated design intelligence grabs the attention not only of researchers and designers, but of other key players in the AEC industry.

The LAMA visit not only granted access to its façade-oriented research, it also yielded some insight as to how the lab approaches real construction projects. Paul de Ruiter began with a presentation that profiles the Pulse building located on the university campus. Pulse is an educational facility with an open layout that encourages group study and collaboration. At the early stages of design, a key objective was energy neutral building performance. Yet one key element is still missing from that initial design, a shading system applied to the southwest façade. With an initial cost estimate of 1.5 million euros, the shading system was value engineered out of the project. Yet the university still intends to find a cost-effective solution for this final element, so that it may consider this project complete and performing as designed. This shading system was designed to permit maximum view while limiting solar heat gain during the warm months. These criteria demanded a system with a high degree of variability, responding to changing sun angles during long periods of exposure. A parametric workflow was appropriated for a design solution and additive manufacturing became the fabrication method of interest.

Four years ago (at the time of writing), LAMA was approached to develop a scheme for the system to be additively manufactured. This project serves to discuss a methodology for approaching design through the guise of additive manufacturing. The following text features excerpts from the conversation.

P: Theoretically, you can print anything. The question is, can you print it cost effective? That’s the main thing. So that’s the idea we had about creating big objects. You have a lot of small elements. Small machines making small objects. The problem you have with small elements is, you have to

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combine them. So, you have connection problems. That is something you try to minimize, especially if you are going for production. It really has to be not like a prototype but a real [manufactured] object. Then you want to minimize the amount of connections, because the more connections you have, the more chance for failure. It adds to the complexity of double material, so it becomes additional weight. The second option is to create a bigger machine. In this case, we had a robot. So, something like [the robotic arm] would be an option or [the extrusion chamber]. It can make bigger stuff, or a mobile one [the three-arm robot]. And of course, it doesn’t matter where you are, it can print.

RF: With this mobile printer, would the idea still be that it is printing horizontally, on a plane parallel to the ground?

P: It can print vertically. It doesn’t matter. Say for example you want to add an element to the wall. Of course, you need a part that is stuck to the wall.

That’s important. You can think about it. You already have, for example, a bolt partially stuck in the wall. You can print around it and actually encapsulate the bolt, so automatically it will be fixed. And then it doesn’t matter, you can print at any angle.

RF: And so the direction that the filament comes out, it doesn’t really matter.

P: No. The question that you will have is- will it support the print? You need some serious cooling in that case. If it is still fluid, or partially fluid, it has the tendency to bend because of gravity. You can avoid this by having some serious amount of cooling in it. So, it cools so fast that it will actually be locked in its position. Theoretically, it is possible. You can even print upside down if you want.

“Theoretically, you can print anything. The question is, can you print it cost effective? That’s the main thing.

So that’s the idea we had about creating big objects.”

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RF: Do you think printing in very cold temperatures would be advantageous?

P: Um, no. Because then, you need to have control over it. So, you need local cooling, not over the whole system. Then it works best.

Back to presentation...

P: Of course, you can use bigger robot arms. Of course, that is very expensive. Print farms – lot of small machines. And of course, the first attempts are already made with mobile systems. So, we end up with something like this [the three-arm robot]. The other thing was, the size of the panel. [It] meant that the printers you have to buy are already expensive. So, what we did, we decided: what if we build our own 3D printer, and then make it lowcost? That automatically means that you go to a manufacturing method, or a material which aligns with FDM7 printing. It’s a way of printing that allows you to build machines by yourself, a relatively simple technique. You can get all the components online. Without any problem you can just build it.

The goal was to get the cost down, from 2400 to 90 euros [per panel]. So that is approximately 4 percent of the original cost. And that is of course, a challenge. So it is not the technology that is there. You have all the technology that you need to print whatever you want. The biggest challenge is the cost. You have to think about how you can get this out. We built our first flimsy delta, which was able to print one panel in eight hours. And, that allowed us to actually calculate how many machines we needed. In this case we have a print cell, which is six of these elements connected to each other.

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And they will print six panels a day. And then the idea was at the end of the day, the cost of these ones, a print cell like this, was 12,000 euros. But in this case, you have six machines for it. So that’s 2000 euros a machine. The idea was to build two of them and then you have the capacity of building 12 panels a day, during the day and then at night you can print another 12 panels.

RF: Can someone just let it go by itself and walk away?

P: If you build them correctly, it is possible. And it depends of what the shape is of the object you are printing. So that also had to be taken into account, the design of the panel. So, you can see that the rationalization process is geared not only to minimize material but also to optimize the effectiveness of the machine to reduce print mistakes.

P: We use different kinds of techniques for this. Generative algorithms, where an optimal solution is found for the calculations related to the purpose. Then we add an additional step which is related to a cable structure.

The structural engineer added a cable system through the panels. And that made the panels extremely complex. This at the end was the section of the panels (referencing laptop presentation). And each line is actually a pass of the extruder. So you can see that you have a minimal amount, absolutely the minimal amount of movement of your extruder. So you had two things, you had the problem of, first of all the amount of panels, like 700. Then you had the problem is, how fast can you manufacture them. And, how cheap can you manufacture them. The fast and the cheap [are] directly related.

The faster you print, the less time it takes, the less machine time, less material. That meant that we went for full optimization of the section, where if you take out any material out of this panel, it actually will collapse. So the whole thing from a structural point of view is completely optimized. From a manufacturing point of view, completely optimized and from a material point of view, completely optimized. And therefore, optimized for the machine. And this is actually the final panel. This is one printed panel. And that was printed in this machine (points to robotic arm) this big one. And the idea was a panel like this would be printed in eight hours. So during

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the day it will print one and at night you set on the other one. So that was the final design. What you notice is that as soon as you start optimizing at this level, it is not only the shape for the function, it is actually the shape for the manufacturing. Minimize the amount of material, but also the shape for the structure, for the cable structure. If you combine it all together, you get extremely complex shapes. These panels look quite simple, but if you look at the actual 3D files you see that nothing is straight. Everything is at an angle. Nothing is similar. Everything is slightly different. And so, what you will generate is – you try to solve the problem of function, of cost and of manufacturability through shape. That is actually what you are doing. And then of course, using a 3D printer makes sense. Because it can generate a lot of shapes way easier than other manufacturing processes.

PVDF contains a fluoride component. When exposed the extreme heat, the fluoride in this compound converts to acid and has the capacity to burn through steel. It was this material characteristic that killed the initial design. A lull period ensued but after some reflection, LAMA approached the architect and proposed a different material.

P: In this case, ASA. [It] is also used in the car industry, for bumpers. It is a material that is relatively safe to print. It has styrene in it, so you need ventilation. It is not as dangerous as PVDF. The other thing is, we also looked at new manufacturing methods. There’s a new machine available. We are in a consortium together with a manufacturing company, who actually uses this big 3D printer. And this one can extrude 25 kilograms per hour.

And the idea was, okay let’s changes the panels [so they can fit] in the big machine. And then also the design was changed, because the machine was changed. And then we started noticing that again this actually would be quite competitive with traditional sun shading systems.

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R: This is because you scaled up?

P: Bigger? But the previous one was already competitive with a traditional sun shading system. But this one is simpler, because the panels are bigger.

We don’t need the cable structure anymore. And that makes the whole structure simpler. And the material was way cheaper. So the pervious [iteration] was I think 15 percent more than a traditional system. But 15 percent is something you can say, well okay you have a unique system for it. And the PVDF would stay on there for 30 years without any problem.

P: This [new] system, the material costs are half. So that means that you are already, if I look at the material cost in general I think it would save you 30 thousand euros. So that means already you are below the normal cost of a sun shading system. And the reason why this is, is because not only have you optimized everything for its functionality, minimized material use, maximized the efficiency in manufacturing, but also you can design it in this whole system the way how you actually assemble it on the building, which might be way cheaper. You can actually integrate this in your geometry. And that was something we learned with this project. Because we were really on the last step of go, no go for production. And [the university] said we find it a bit risky to go for the PVDF. Understandable, but at that moment we knew that it was already competitive with traditional solutions.

Even though it wasn’t made, that was the most valuable information that we could get out of the project.

For a bit of context, it deserves to be mentioned that there were 24 people involved in this project, including the client (TU Delft University), the architect, the structural engineer, LAMA as a consulting research lab and its network of consultants, including chemical engineers affiliated with the university.

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P: So we work with 24 people on this project, including different universities, different departments, also different chairs, with the architect, with the client. It was really like a building project. Also, manufacturing with the Leap Frog8. So we got extremely close to getting it done. That is the biggest advantage of the method we are using. We [use] optimization techniques in our design process in general. This can be optimization for energy saving, getting the maximum light in without heat for example, [processes] we are used to applying. By extending this [to] the manufacturing process, [it] allows you to really tweak the design which you are making. If you put that in one holistic approach, from concept design to manufacturing to the [end] of life part, where you actually say after 30 years we get from the façade, you already take into account how you extract it, and then what you can do with the material. [This] actually means what you have in the system, which can be compatible with traditional solutions and will be fully recyclable, instead of partially or downgraded, down cycled.

P: This was four years ago. Nowadays, the techniques which are available also for large scale printing, high volume extruders for example, which four years ago were rare. Now you can buy them off the shelf. So the extruder which you can see there (points to extruder). That’s a five-kilogram extruder which we mount on the robot arm, which allows us to make these panels. Where another one, this capacity is five times higher, which allows us to print faster. And, that is something that is really interesting. So, what you can see now in general, in the industry. The industry is recognizing the potential of 3D printing, in general. It steps away from only looking for prototyping. You can see now that these additive manufacturing techniques are actually applied in manufacturing. And that means that you not only create one object, but you can create five thousand, even ten thousand objects. So when [we] make something for the 3D printer, what we try to do is add functionality to it, which you normally can’t get another way.

To illustrate this point, Paul referenced the SpaceX SuperDraco engine chamber, an example of additive manufacturing procedures entering the aerospace industry. Companies are opting for this technology because it permits the consolidation of various manufactured parts. Once separate components requiring the additional step of post fabrication assembly are now manufactured as single units. The high precision results are made possible with a powder bed filled chamber acting as a supporting structure during the additive phase, followed by a subtractive cnc finishing stage9.

A more grounded example of AM proving more competitive that traditional manufacturing comes from the collaboration between Renishaw and Empire Cycles. The result is a 3D printed titanium alloy bicycle frame that is 44% lighter than its aluminum version. When compared to casting methods this frame has a higher tensile strength as the metal achieves near perfect density.

In addition, the strength of titanium alloy is favored over carbon fiber due to its resistance to impact10.

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Summary

A key point from the conversation with Paul could be summarized as follows; the technology already exists to print any shape, regardless of complexity. The main constraints will be time and material. Thus, additive manufacturing forces the designer to propose solutions that require the least amount of material as well as think critically about the printing process. If small, simple objects are needed, a printing farm may be considered. On the other hand, large scale, high resolution components may require one costly robotic arm or powder bed printing chamber. In this latter scenario, the fabrication process is not easily scalable, and predicated on the rate of a singular printing unit. This forces one to think holistically about the optimization of the designed object versus manufacturing method. Economics will dictate that if a design is to be realized, the planning process should consider possible approaches to fabrication from the onset. Even more significant in the case of additive manufacturing, the consequences of not curtailing design to fabrication may prove that certain schemes are not financially viable.

In the case of the Midtown Viaduct display model for the Venice Biennale, Paul was able to put things in perspective. Per his advice, a simple test was in order. One could select all the lines that define the bridge structure and calculate the composite length. Multiply the length by the rate of a given printer and period of fabrication is determined. Approached from another angle, one could test a small portion of the bridge and establish a rough delta. For all the time spent designing and refining the Midtown Viaduct structure, it became apparent that no one had considered composite length of all mesh face outlines. During the most laborious phases of competition production, this simple exercise might have been the farthest thing from anyone’s mind. Furthermore, during the planning stages of the Biennale exhibit, the team had not yet grappled with this first step in understanding the constraints of additive manufacturing. Yet the task would

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be necessary to have a realistic conversation with MX3D. Total length would be a key factor in generating a quote for dot weld fabrication. Thus, to this end, the display model was analyzed.

The first trial occurred in the Rhino/ Grasshopper environment. The original display model measured 0.64m x 3.84m x 0.55m (x,y,z respectively). Selecting the mesh and running it through simple GH definition revealed a total measured length of 909.6 meters. The promotional videos found on the MX3D website were aspirational but did not allude to high speed robotic welding because the requisite cooling process demands a slow rate. Multiply this rate by .9 kilometers and it becomes clear the proposed job would require an excessively lengthy production period.

Understanding this dilemma, it became clear that the model resolution had to be edited. A bit of retooling in Blender allowed a simple modification to the original mesh count. There is a “decimate” function that allows the mesh to be “unsubdivided,” effectively reducing the composite length while progressively eroding the model’s fluid characteristics with each iteration.

With two clicks, the model’s face count is reduced by 50% and it appears this was the threshold beyond which the form’s character would be compromised. The resulting composite length was 451.5 meters. Both versions were exported as a dwg file and forwarded to MX3D. About two weeks passed and technician Thomas followed up with some questions. Rather than fabricate each quad intersection at <90 degrees, he proposed bringing that adjacency angle down to 35 degrees. The modification was approved for pricing purposes but one week later, more modifications were proposed. For the sake of optimization, Thomas expressed that the quad mesh (square module) should be converted to a diagrid (x module). This, he suggested, would permit a more efficient welding process.

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He submitted a diagram communicating the proposed design change, but it became clear that the original form would have been too compromised with this series of modifications. On the subject of price, the 451.5-meter model as a diagrid would cost anywhere from 27,000 to 32,000 euros, excluding taxes, labor and shipping. Hopefully it comes to no surprise that this fabrication approach would be cost prohibitive. What is surprising in this context, given all the cited advancements in additive manufacturing, is that there still stands much in the way between digital model and reproduced tactile form if we are considering robotic welding.

Back to university work, it may be of no small coincidence that students (who are often hard-pressed for time and money) are showing interest in cellular and lattice structures as the basis for generative 3-D printed work.

These systems possess an inherent economy of material (print time), rigidity and lend themselves to free-form creation. Algorithms based on cellular automata are becoming increasingly popular within architecture schools around the globe1 and this experimentation may soon find a place in more

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avant-garde practices. For students, there is always the pitfall of not fully understanding the algorithm as they negotiate and tweak certain parameters that were defined elsewhere. Nevertheless, with increased literacy and practice, these experiments become more commonplace. These design approaches lead to new structural systems that challenge our understanding and approach to additive manufacturing. Regarding feasibility, like all emerging technologies, time reveals that early limitations inevitably give way to expanding capabilities. Today we are witnessing this in other science-driven sectors i.e. prosthetics and automotive industrial design. As these fields lay the groundwork in research, the AEC industry will in-turn attempt to apply those early lessons to manufacturing building and/ or structural components. In many ways, MX3D and Joris Laarman Lab are at the forefront of this endeavor, negotiating with governmental agencies and testing laboratories to ensure that their 3D printed form can serve as a permanent pedestrian bridge spanning a canal in the heart of Amsterdam.

Some closing notes to consider: -A case can be made that additive manufacturing is entering the marketplace.

-To keep pace with related industries, it is advisable that architects retain some literacy with AM. -Consider additive manufacturing only if there is added value in the process, especially if this value cannot be achieved otherwise.

-Design optimization is essential when considering AM. -Design optimization is difficult to achieve is AM is not considered at the onset of the design process.

-Additive manufacturing can be evaluated through a function of time and material cost.

-Time and material are a function of optimization.

-Keeping pace with AM requires constant surveillance of all related industries, as the technology continues to advance rapidly.

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Footnotes Introduction 1. Gheorghe, Andrai, DADA Digital Architectural Design Assertion (Basel, Birkhauser, 2019), 12-17.

2. Sanchez, Jose, Blindspot Initiative: Design Resistance and Alternative Practice (Los Angeles, Evolo Press, 2018), 84-119.

3. Jakob Schoof, Digital Baroque in the Red-Light District: Pedestrial Bridge in Amsterdam, https://www.detail-online.com/article/digital-baroque-in-the-red-light-district-pedestrianbridge-in-amsterdam-33468/ MX3D 1. Jakob Schoof, Digital Baroque in the Red-Light District: Pedestrial Bridge in Amsterdam, https://www.detail-online.com/article/digital-baroque-in-the-red-light-district-pedestrianbridge-in-amsterdam-33468/ 2. See ABB website, The Lean Arc Welder, https://new.abb.com/products/robotics/industrial-robots/irb-1520id 3. Gunseli Yalcinkaya, World’s first 3D-printed steel bridge unveiled at Dutch Design Week, https://www.dezeen.com/2018/10/22/worlds-first-3d-printed-steel-bridge-completed-mx3dtechnology/ 4. Jmg Van Den Elshout (Janneke), The world’s first 3D-printed metal bridge in the world is coming to the UT campus for testing https://www.utwente.nl/nieuws/2019/9/511264/eerste3d-geprinte-metalen-brug-ter-wereld-komt-voor-testfase-naar-ut-campus 5. MX3D, MX3D Bridge, https://mx3d.com/projects/bridge-2-2/ DUS / Aectual 1. Amy Fearson, DUS Architects builds 3D-printed micro home in Amsterdam, https://www. dezeen.com/2016/08/30/dus-architects-3d-printed-micro-home-amsterdam-cabin-bathtub/ 2. Amy Fearson, Dutch EU building features a façade combining tensile fabric and 3D-printed bioplastic, https://www.dezeen.com/2016/01/12/european-union-3d-printed-facade-dus-architects-holland/ TU Delft 1. Robotic Building, http://www.roboticbuilding.eu/ 2. LAMA, http://designinformatics.bk.tudelft.nl/index.php?page=lama 3. Valeria Piccioni. “The AM Envelope” (Master Thesis, TU Delf, 2019), 10-11.

4. Ibid, 14-15.

5. Ibid, 137-38.

6. Sarakinioti, Maria-Valentini et al. Development and prototyping of an integrated 3D-printed façade for thermal regulation in complex geometries. Journal of Facade Design and Engineering, [S.l.], v. 6, n. 2, p. 029-040, june 2018, https://journals.open.tudelft.nl/index.php/jfde/ article/view/2081 7. Fused Deposition Modeling (FDM), or Fused Filament Fabrication (FFF), is an additive manufacturing process that belongs to the material extrusion family. In FDM, an object is built by selectively depositing melted material in a pre-determined path layer-by-layer. The materials used are thermoplastic polymers and come in a filament form.

3D Hubs, https://www.3dhubs.com/knowledge-base/introduction-fdm-3d-printing#what 8. Leapfrog, https://www.lpfrg.com/ 9. Hansel, Adam et al. Study on Consistently Optimum Deposition Conditions of Typical Metal Material Using Additive/Subtractive Hybrid Machine Tool. (Procedia CIRP, 2016), 579-582, https://www.sciencedirect.com/science/article/pii/S2212827116303018 10. Renishaw, https://www.renishaw.com/en/first-metal-3d-printed-bicycle-frame--24154 Summary 1. Carpo, Mario, The Second Digital Turn: Design Beyond Intelligence (Cambridge, MIT Press, 2017), 96.

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