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Machine Learning & Geopolymers: 3D Printing for Construction

Ali Bagheri and Christian Cremona explore complexities in digital fabrication, sharing their findings in the recently published ‘Formulation of mix design for 3D printing of geopolymers: A machine learning approach.’

Focusing on 3D-printed materials for construction, Bagheri and Cremona assess the potential for machine learning. Experimenting with geopolymer samples and different compositions, the authors evaluated target variables in machine learning. They began by looking at the compressive strength of geopolymer binders and the elements involved, to include:

  • Features of raw materials
  • Chemical composition of the aluminosilicate resources
  • Formulation of the alkaline activator
  • Alkaline ions in the activator
  • Fraction of silicate to hydroxide compounds in the activator
  • Water to binder ratio
  • Formulation of aggregates

Upon 3D printing, factors grow to include:

  • Printing method
  • Layer resolution
  • Shape of prints
  • Rates of extrusion
  • Orientation
  • Preparation and formulation of materials

“Given an innumerable number of independent variables, the prediction of the compressive strength of printed geopolymer samples without the use of a machine will generate a high level of error,” stated the researchers. “For instance, one can predict the strength of samples that are classified into four categories with 75% error. However, the use of machine learning would reduce this error significantly as can be seen further in this work.”

Current data offers benefits to researchers as they are able to learn more through printing variables and changing parameters:

“Among the mentioned effective parameters, the content of the fly ash, the content of the ground granulated blast furnace slag (GGBFS), as well as the ratio of boron ions, silicon ions, and sodium ions in the alkaline solution have the most significant impact on the compressive strength,” stated the researchers.

A small 3D printer was used to fabricate samples for the study, consisting of a piston-operated extruder. The researchers used vibration to make sure the mix was compacted, with resulting sample dimensions of 250x30x30.

Statistical summary of the input data

Target data classes

Slag was found in the geopolymer mix, and also displayed better compressive strength; conversely, samples with more sodium showed decreased compressive strength.

DT flowchart of the ctree function

Increased boron raised sodium ions, while lessening compressive strength—with the same shown in terms of lesser slag content too. Silicate is also a critical ingredient for strength development and cross-linking.

Confusion matrix of ctree function based on actual values

Confusion matrix of ctree function based on predicted values

Ultimately, Bagheri and Cremona discovered the true prediction value to be 63 percent.

Confusion matrix of rpart function based on observations

Confusion matrix of rpart function based on predictions

“The predictions could be compared in two efficient ways. First, the simplicity of the model could be assessed based on the predictions rules and comprising the number of parameters. Accordingly, rpart function is far more uncomplicated with only two parameters for 50% of the predictions and three parameters for another half,” concluded the researchers.

“Whereas, ctree function used four factors for 74% of the predictions and two factors for only 26% of the predictions. Secondly, the cumulative accuracy of each prediction function was used as a comparing criterion. The cumulative accuracy factor was obtained by multiplying the number of predictions in each category and the appropriate positive predictive value.

Acquiring 70% cumulative accuracy for rpart function with respect to 63% for that of ctree function evidenced similar but slightly better performance for rpart function to predict the compressive strength of 3D-printed boron-based geopolymer samples. Moreover, the importance of the percentage of slag and the ratio of boron ions can be seen in the decision trees created by ctree and rpart functions, respectively.”

3D printing in construction continues to be of growing interest, with the potential for homes, offices, and even entire villages to be built with a variety of different printers and materials. What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

Comparison of the results: from laboratory test to machine output

[Source / Images: ‘Formulation of mix design for 3D printing of geopolymers: A machine learning approach’]

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Nanyang Technological University: Processes & Materials in Large Scale Concrete Printing

Yi Wei Daniel Tay of the School of Mechanical and Aerospace Engineering at Nanyang Technological University recently submitted a thesis, ‘Large scale 3D concrete printing : process and materials properties,’ exploring the potential for more progressive techniques and materials in the construction industry.

This research examines the need for good flow in concrete ink, along with challenges in finding the correct printing parameters for performance and quality products. Ultimately, pumpability, layer adhesiveness, and buildability are critical elements as well, with all these features being explored during the fabrication of a large-scale sample—along with the option of refining the need for formwork via 3D printing.

(a) Poor balance between travel speed and flow rate (b) proper balance
between travel speed and flow rate

Not only is pouring concrete in formworks for temporary support a labor intensive process, it is also more expensive; in fact, as Tay notes, formwork comprises 40 to 60 percent of the cost of a concrete frame, and ten percent of the overall building expenses.

Tay realizes the benefits of 3D printing in construction:

  • Shorter building times
  • Cheaper construction
  • Less human labor
  • Reduced material waste
  • Greater latitude in design
  • Better potential for integration of functionality

“All these reductions are eventually translated to cost-saving, which compel the exploration of using 3D printing in construction for structural with customized complex geometries,” stated Tay.

Worldwide, 3D printing with concrete is garnering interest—leading to a variety of different projects and studies, from reinforcement of concrete walls to developing and using fiber additives, to experimenting with progressive new techniques. Methods for 3D printing with concrete continue to grow, to include:

  • Binder jetting
  • Material deposition method
  • Contour crafting
  • Curved-bed printing
  • Mesh mold

“3D concrete printing can be a complicated process, especially if the requirements are not clear. The printing parameters and material properties should be tailored to fulfil the project requirements such as cost and duration,” explained Tay. “With the printing path and speed established, the vertical loading stress can be determined. This vertical stress can be compared with the yield stress of the mixture to determine if it is suitable for printing.

Contour crafting using (a) ceramic and (b) cement material

Concrete printing at Loughborough University

Mesh-mould combines formwork and reinforcement system for concrete

The use of suitable materials is critical, as researchers continually seeking more sustainable options, to include:

  • High volume fly ash concrete
  • Geopolymers
  • Recycled glass aggregates

For this study, graded concrete material was created by varying the printing parameters. As the effects were studied, Tay discovered that both flow and travel speed have enormous impact on filament and dimensions.

“The main advantage of having a functionally graded structure is the reduction in material and the decrease in printing speed as the support structure region uses less material and help to reduce printing time,” concludes the author. “This shows that through topology optimization, this functionally graded material can be manufactured to produce a structure that has improved performance compared to the un-optimized structure.”

Robotic arm printer used for large scale printing

“The future of construction is most likely to be an integrated process that allows the organization to take advantage of both conventional and additive manufacturing technologies. With rapid urbanization in many developing countries, there is an urgent need to come up with clever ideas that optimize the sustainable performance of the buildings that we live and work in. Regulators also play a significant role in sustainable construction by creating the right incentives for companies that choose to build in a sustainable way.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images:  ‘Large scale 3D concrete printing : process and materials properties’]

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3D Printed Formwork for Topology Optimized Reinforced Concrete Walls

In the recently published ‘Topology Optimized Reinforced Concrete Walls Constructed with 3D Printed Formwork,’ authors Triveni Mudaliar, Rémy D. Lequesne, and Matthew Fadden (all of The University of Kansas Center for Research, Inc.) continue where others have left off in exploring 3D printing in the construction industry.

In this study, the authors are focused on two areas of technology: 3D printing and computational topology optimization (a mathematical technique for optimizing structural geometry). In using the two together, the significant benefits include the ability to build structures that are lighter in weight, aesthetically and architecturally pleasing, and reduced in volume. The team built two small-scale sample structures to test the idea for their concept, specifically in using 3D printed formwork for use with complex reinforced concrete (RC) structures.

Examples of topology optimized structures constructed in (a) Blanes, Spain, 2002 (not constructed) (Januszkiewicz and Banachowicz, 2017); (b) Takatsuki, Japan, 2004 (Donofrio, 2016); (c) Doha, Qatar, 2008 (Jewett, 2018); and (d) Lausanne, Switzerland, 2008 (Januszkiewicz and Banachowicz, 2017)

Noting that computational TO allows for more efficient and ‘appealing’ structures, the researchers realize that the technology has so far continued to offer challenges within industries outside automotive and aerospace, due to the following:

  • Challenges in building the irregular and non-linear designs that result from topology optimization
  • Difficulty in applying TO algorithms, generally using homogenous materials to reinforced concrete (RC) structures
  • Insufficient test data of topology optimized RC structures, resulting in limited knowledge of the behavior of optimized structures regarding stiffness, strength, and deformation

Rather than using other alternative techniques or avoiding use of formworks altogether, the authors suggest using a small 3D printer for creating formworks.

Topology optimized (a) UHPFRC slab with four supports (Jipa et al., 2016) and (b) PC beam testing under compression (Jewett and Carstensen, 2019)

“Several researchers have investigated different additive manufacturing techniques to efficiently build complex structures. These new emerging technologies may also speed up the process of construction. Currently, complex topology optimized structures could be directly built using either a D-shape process, contour crafting, or concrete printing,” stated the researchers.

Equipment for fabrication of formwork (a) Robotic CNC Milling, (b) Robotic Hot-Wire Cutting, (c) Robotic Abrasive Wire Cutting, (Sondergaard et al., 2018), (d) 3D Printer (Peters, 2014), (e) 25-Actuator Based Flexible Molds (Raun and Kirkegaard, 2014), (f) Flexible Fabric Formwork (Hawkins et al., 2016) and (g) Mesh Mold which uses uniform reinforcement of RC members as formwork and the concrete is placed inside the mesh (Hack et al., 2017)

During experimentation, the researchers built a control wall (CW) and an optimized wall (OW) as samples meant to show the potential for creating the formwork via 3D printing.

“Both specimens were constructed with base and top blocks. The base block simulated the foundation of a structural wall and was used to secure the wall to the strong floor of the structural laboratory,” stated the researchers. “A 55-kip hydraulic actuator was connected to the top block to apply lateral loads. The lateral force was applied at an elevation of 60 in. above the base block, resulting in an aspect ratio of 4 for both walls.”

“The control specimen was designed so its lateral strength would be limited by flexure using concrete with a target compressive strength of 6,000 psi and Grade 36 reinforcement. Flexural reinforcement consisted of ten No. 2 bars in each of the boundary elements near the edges of the wall. Vertical web reinforcement consisting of two 12-gauge wires (diameter of 0.106 in.) at a 3 in. spacing also contributed slightly to the wall flexural strength.”

Reinforcement details of control wall specimen

The base and top blocks were cast with standard concrete, while the optimized wall was cast with high-strength concrete bearing a strength of 12000 psi. This mixture was meant to offer greater strength along with making up for the section loss—due to openings.

Reinforcing bars before (left) and after (right) the HCL treatment

PLA was used in the fabrication of the formwork for the optimized wall.

3D printed test specimens under three-point bending test. Specimen printed so the joint between layers was (a) in the vertical plane parallel to the longitudinal axis and (b) in the vertical plane perpendicular to the longitudinal axis

A 3D printer with 16×16 baseplate and total printing height of 21 inches was used for fabricating the optimized wall:

“A uniform formwork wall thickness of 0.125 in. was used throughout. The dimension was selected based on initial trials. The thickness was also selected such that the volume required to print one subpart of formwork was less than the volume of a spool of Polylactic Acid (PLA), the material used to print the formwork.”

Support structure/falsework and formwork for top block in control (left) and optimized walls (right)

One of the most serious constraints in the optimization of the RC structures was that the researchers found they could not use reinforcing bars for the sample used for optimization.

“These features of the algorithm were accommodated by using a rule of mixtures to define the stiffness and density of an effective composite material in the models used for analysis. However, this approach does not provide for a fully optimized composite system. It is reasonable to expect that an algorithm which somehow considers the presence of discrete reinforcement would produce a different optimized geometry,” concluded the researchers.

Principal strains at 6-kip lateral force in optimized sections designed to have strengths of at least 6 kips with volume ratios of (a) 0.51, (b) 0.65, (c) 0.74, (d) 0.84, and (e) 0.92 (element type C3D10, 0.5 in. mesh size)

“Future work could be aimed at producing optimized geometries for reinforced concrete structures subjected to loads beyond those required to cause concrete cracking or yielding of the reinforcement. A challenge for topology optimization of RC structures is not being able to include the use of discrete reinforcing bars in the model and having to use linear material properties. These features of the algorithm were accommodated by using a user defined composite material to define the rigidity and density of an equivalent material in the models used for analysis. However, this approach does not provide for a fully optimized composite system after cracking and yielding because reinforcement placement and the redistribution of stresses associated with cracking are not considered during the optimization process. It is reasonable to expect that an algorithm which somehow considers the presence of discrete reinforcement and concrete cracking would produce a different optimized geometry.”

3D printing in construction today continues to be a source of study and furthered development as researchers and builders around the world fabricate homes, offices, and concrete structures. What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Topology Optimized Reinforced Concrete Walls Constructed with 3D Printed Formwork’]

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Researchers Assess the Use of 3D Printing Geo-Polymer Concrete

In the recently published ‘Life Cycle Assessment of 3D Printing Geo-polymer Concrete: An Ex-ante Study,’ authors Yue Yao, Mingming Hu, Francesco Di Maio, and Stefano Cucurachi examine the development of geo-polymers in concrete, and delve further into the use of 3D printing within the construction industry.

With the environment in mind, the authors are assessing the efficacy of using 3D printing and geo-polymers to replace conventional manufacturing methods with conventional materials like Portland cement. Environmental performance was evaluated through an ex-ante life cycle assessment (LCA), with manufacturer data used to pinpoint items for improvement and ‘scaled-up scenarios’ created in partnership with the company as the researchers looked into areas for improvement.

Contribution analysis on climate change.

Waste reduction is high on the list of benefits in terms of 3D printing in construction and with cement, and while geo-polymer could have even higher environmental impacts than ordinary concrete, the study shows that with multiple improvements, it could reduce the carbon footprint. The researchers were able to achieve this by lowering the amount of silicate in geo-polymer ‘recipes.’

Previous studies show that 3D printed buildings are higher in efficiency, lower in emissions, produce less waste, and consume less energy. Ex-ante LCA helps the researchers here evaluate the merits of fabricating a GP concrete object through inkjet 3D printing.

“Aiming at combining environmental management and technology development, in close-collaboration with technology developers, the study shows that ex-ante LCA can not only estimate the potential environmental impacts, but, more importantly, provide directions for the future deployment of 3DPG technology from the current lab-scale experiment,” state the researchers.

There were still some facets of the suggested improvements, however, that would be difficult to integrate in the near future:

“The technology readiness level (TRL; Moorhouse, 2002) of the 3DGP concrete technology in this research is estimated to be 6, which is already on technology demonstration stage,” stated the researchers. “This would suggest using LCA even at an earlier stage of the TRL trajectory to guarantee a greater support of technological innovation, when the core components of a technology are more flexible to change.”

The technology being explored is emerging—just like the accompanying market—but the researchers state that it is also reasonably complex. The researchers worked with technology developers in relation to the following potential for the future:

  • Technological landscape
  • Market penetration
  • Commercial data
  • Overall feasibility

The researchers also created numerous scenarios, including those titled ‘what ifs.’

“To generate ‘what-if’ scenarios, hotspots analysis is performed and then four scenarios are developed based on improved hotspots, using the hotspots as building blocks. Thus, hotspots analysis be a structured method to develop scaled-up scenarios in ex-ante LCA studies. For the application of the framework of the ex-ante LCA methodology to other technological systems, additional scenario types and generating methods need to be considered as additional case studies and methodological contributions become available,” stated the researchers.

LCA helps researchers and analysts gain insight into environmental performance, as well as highlighting possible challenges, early on. The authors described this study as going from ‘cradle to gate’ as they analyzed the three stages of the 3DGP concrete system:

  • Raw materials
  • Transport
  • 3DGP concrete manufacturing

The summary of research processes (Adapted from Villares et al., 2017)

The details of four scenarios used in this study.

Overall, the researchers were concerned with some ‘discrepancies’ regarding 3D printing, attributed to the variances between raw materials, combined with different hardware. Silicate, however, stood out as offering ‘considerable impacts’ on the manufacturing process, and better results.

“The current study setup excludes the use-phase and end-of-life phase for both technology systems. While the environmental impacts of 3DGP concrete and ordinary concrete in the use phase are similar, the collection, treatment, and potential recycling ratio of these two alternatives may be different after utilization,” concluded the researchers.

“3DGP concrete does not have an advantage over ordinary concrete from the perspective of the transportation of raw materials. For ordinary concrete, the supply of raw materials operates at full commercial scale, due to the mature nature of the market. The transportation distances of raw materials are not long for ordinary concrete. These aspects do leave still little room for improvements and rationalization in the use of resources.”

The flowchart of 3D printing geo-polymer (3DGP) concrete

3D printing in the construction industry and with concrete is becoming more common as industrialists realize the enormous advantages, experimenting with reinforcing spatial structures, examining parameters in 3D printed concrete, even 3D printing self-healing capsules for cement.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Life Cycle Assessment of 3D Printing Geo-polymer Concrete: An Ex-ante Study’]

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3D Printing in the Construction Industry: Still Evolving

In ‘Success Factors for 3D Printing Technology Adoption in Construction,” thesis student Pankhuri Pimpley at the University of Maryland, College Park, explores not only the history and benefits of 3D printing but also its effectiveness overall in a competitive, demanding market.

While 3D printing was created in the 1980s and introduced to the construction industry in the 90s, its purpose in that application was mainly for rapid prototyping. Such a process offers huge benefits to industrial users, but as with so many other industries and applications, it wasn’t long before ambitious users wanted to use digital fabrication to make real parts.

General 3D printing process (S. Lim et al., 2012)

As further advances in automation are still needed for the construction industry, 3D printing has become a very attractive option. The advantages abound too—from more savings on the bottom line to greater efficiency and less need for labor, to a continually expanding array of available materials. The author’s discussion as to why 3D printing is needed in construction is compelling:

“The construction industry has been slow in adopting new methods and innovations due to deep confidence in the efficiency of traditional processes, materials and codes. Since no change or innovation proposes growth of the sector, the construction industry has one of the lowest productivity increases compared to other industries. It is even more important to automate construction activities given the risks associated with it,” states the author.

“About 400,000 people are injured or killed every year in the USA during construction. These injuries and fatalities eventually translate to costs for society. Construction is also prone to corruption and political feuds. Hence the primary need for 3DP in construction is to reduce or eliminate human involvement in the design and development of the structure. It is also important that 3D printing be considered a standard construction practice by code bodies. Accepting the innovation can help set a common standard for global construction and solve the problem of labor skill variation from demographics and experience.”

3DP frame of concrete printing system (Sungwoo Lim et al.,2018)

Large-scale mobile printers are popular in the construction industry, and we have followed many of them such as the WASP 3D printer, which has been used for the beginnings of creating an entire community, along with tiny houses, and more. Pimpley points out numerous other examples too of companies with ambitious plans also, many of them eager to build small structures in record time—including Eindhoven University of Technology in the Netherlands, planning to print five single-story, two-bedroom residences.

Startups offering range of 3DP services

Pimpley also gave great attention to how socioeconomics might affect 3D printing, along with considering how to manage such factors in the future. One of the most important items that Pimpley points out, however, is that within the construction industry overall, the actual usefulness of 3D printing is ‘still limited.’ The author explains to us that this is due to certain issues related to society, the general market, and other business-related reasons.

“Nine success factors and forty-two corresponding measurement items have been identified and analyzed through literature review, case studies, surveys, interviews and correspondence with worldwide construction 3D printing experts and professionals. All factors are finally determined important to consider for the success of a construction 3DP project at its current phase. Relative significance of the factors and measurement items have been determined based on 82 questionnaire survey responses,” concluded the researcher.

“Altogether, the findings can help achieve an understanding of 3DP and increase the likelihood of successful adoption in various sectors within construction.”

Eindhoven’s proposed home design (“3D Printed Homes – 4 Most Fascinating Projects in 2019”, 2019, February 20).

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

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3D Printing News Briefs: November 7, 2018

We’re starting with more formnext announcements on today’s 3D Printing News Briefs, then moving on to classes and workshops. Verashape is launching a new 3D printer at next week’s event in Frankfurt, while Cubicure will be presenting its new CSS software solution for 3D printing. In the meantime, SelfCAD is releasing an updated version of its software. Finally, the EU-funded METALS project has published an online 3D printing course, and the people behind a new program for 3D printed construction technology in India are organizing a workshop on construction 3D printing.

VSHAPER 500 Med Launching at formnext

Just like Polish 3D printer manufacturer Verashape introduced its 5-Axis VSHAPER 3D printer at last year’s formnext, the company is taking advantage of the 2018 event in Frankfurt, estimated to gather a record number of participants in its largest space yet, to launch its newest 3D printer – the VSHAPER 500 MED, which was developed to meet the growing demands for spatial printouts used in the medical field. The VSHAPER 500 MED, which includes a vacuum table, a closed chamber with UV light, and silver-based antibacterial coatings, is perfect for creating precise, high quality 3D printed medical models. The 3D printer also has a 420 x 420 x 400 mm workspace, along with an extruder with two V-JET heads.

“3D Printing technology is becoming an increasingly valuable tool in medical diseases treatment, fighting disabilities and increasing the effectiveness of complicated surgeries,” said Marcin Szymański, the company’s VSHAPER Product Manager. “The technology is already used to aid the creation of dental crowns, bone parts, blood vessels and hip-joints prosthetics.”

To see the new VSHAPER 500 MED 3D printer for yourself, visit Verashape at formnext from November 13-16 at Stand 3.1-G88.

Cubicure Presenting CSS Software Solution at formnext

Cubicure, a spin-off company of TU Wien, will be presenting its new, platform-independent software solution for additive manufacturing data preparation at formnext. The software, called CSS for Cubicure Support & Slice, can generate complex support geometries, as well as edit STL files. The comprehensive tool allows users to generate, edit and repair 3D models, in addition to easily exporting layer information for the 3D printing process. Developed with graphic software provider DeskArtes and based on 3Data Expert, CSS is applicable for DLP and SLA (stereolithography), and Cubicure’s own Hot Lithography technology, and also comes with an intuitive import function of several surface models, a user-friendly GUI, and data conversion tools.

Dr. Robert Gmeiner, the CEO of Cubicure GmbH, said, “With this software solution Cubicure offers another important product for the additive manufacturing value chain.”

You can visit Cubicure Booth G59 in Hall 3.1 at formnext.

SelfCAD Releasing Updated Software

Browser-based 3D design platform SelfCAD, founded in 2015, combines 3D modeling, slicing, and several other tools and functions in one easy program. Now, SelfCAD has launched an updated version of its software, which was developed based on users’ expectations of powerful but easy to use 3D modeling software. Version 2.0 of the modeling software includes more capabilities, like a 3D sketching toolset to increase the user’s level of freedom, and simplified design, including an intuitive user interface with a less confusing toolbar that makes it easy to use, even for beginners.

Additional features include new selection modes, a simple objects view with both light and dark modes, a measurement option for easier design of accurate models, new sketching brushes, and new shapes. What’s not new is that SelfCAD, with a price of $14.99 a month or $139.99 a year after a 10-day free trial.

METALS Project Publishes Online 3D Printing Course

The three-year MachinE Tool Alliance for Skills (METALS) project, funded by the European Union under the Erasmus+ program and coordinated by CECIMO, ended last week, but not before releasing a free, online course about the fundamentals of AM. The project was characterized by a comprehensive partnership across Germany, Italy, and Spain, with a goal of increasing the competitiveness of Europe’s machine tool industry by providing the necessary skills to benefit from new disruptive technologies, such as 3D printing. The e-learning course, which is available in English, German, Italian and Spanish, intends to support the development of the AM workforce, and includes 27 learning units divided along three main areas: knowledge of AM, work-process, and entrepreneurship.

“Training and education are important elements for the industrialisation of additive technologies in Europe, which is the objective of CECIMO,” said Filip Geerts, CECIMO’s Director General. “With METALS, learners will be able to access relevant online knowledge at no cost and start building their competences to interact with AM. Coupled with on-hands training, which remains essential, initiatives like METALS are useful to increase the overall awareness of what AM concretely is and entails.”

National Workshop in India on 3D Printing Construction

Indian 3D printing startup Tvasta Manufacturing Solutions, based out of Bangalore and Chennai, is a design and manufacturing organization that specializes in industrial 3D printing. The startup, founded by a group of alumni from the Indian Institute of Technology Madras, developed India’s first 3D printed concrete structure in collaboration with the IIT Madras Civil Department. Now, Tvasta and IIT Madras are organizing a national workshop, to be held in Chennai on November 16, all about 3D printing in construction.

The objective of the conference is to present how construction 3D printing has the potential to majorly boost the country’s affordable housing sector. Many reputable speakers from around the world, including academic and industry experts, have been invited to speak about developments in automation, specialized concrete mixes, structural design, and other topics during the workshop. The conference will be held in the IC & SR Auditorium at IIT Madras.

Discuss these stories and other 3D printing topics at 3DPrintBoard.com or share your thoughts in the Facebook comments below. 

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Indian Institute of Technology Madras Develops 3D Printed Homes That Take Three Days to Build

As 3D printing just continues to gain traction around the world—contributing enormous benefits and innovation to a wide range of industries—India has been embracing the technology and making strides with many different applications. Now, faculty and alumni at the Indian Institute of Technology Madras have developed a new program for 3D printed construction technology and have fabricated their first building.

Meant to act as a start-up for a ‘re-envisioned construction process,’ the academic team is currently developing a 3D printing process that will allow them to create 320-foot, one-story homes within three days each. They are working from a progressive prototype that has already been created at the Institute, offering a concept that allows them to use all the benefits of 3D printing to fulfill the demands for housing in India. Affordability is a huge factor, along with speed in production time, less need for construction labor, and less challenge in transporting more expensive, and dense, materials.

“Building Technology and Construction Management Division at IIT Madras is a unique Research Group in the country which has the expertise in materials as well as construction technologies which is relevant to this effort,” said Prof. Koshy Varghese, Department of Civil Engineering, IIT Madras.

“We have been working on developing 3D printing technology in the area of Construction from 2016 and have conducted International Workshops and awareness sessions for this in Chennai. In addition, the institute is exploring automated construction methods and novel formwork systems for rapid housing construction.”

Along with this current startup, IIT Madras is working with other government divisions to encourage education about—and the use of—technologies like 3D printing.

“3D printing of concrete gives a new dimension to construction. This technology can best meet the complex demands of modern architecture with concrete. The use of a combination of binders and optimally proportioned and sized aggregates, along with suitable chemical additives, the concrete mixture is fine tuned to achieve the rheological characteristics that make it possible for extrusion of the material and shape retention after placement,” said Prof Manu Santhanam, Department of Civil Engineering, IIT Madras.

The government realizes the need for innovation in construction processes as housing issues become further pressing:

“It is very heartening to see that institutions like IIT Madras and new startups such as Tvasta building technologies like 3D printing for construction sector in India from the ground up under the ‘Make in India’ platform,” said Kranthi Valluru, Assistant Secretary, MoH UA. “Such technologies help in expediting construction with optimal use of resources. They help in bringing a paradigm shift in construction sector which is very much the need of the hour.”

Aside from prototypes, it is expected that Tvasta will produce the first 3D printed homes within a year.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: The Hans India]

Indian Institute of Technology Madras faculty and alumni have developed the country’s first 3D Printing Construction Technology and have successfully built India’s first 3D Printed Structure.

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Contour Crafting Will Develop Concrete 3D Printer for Disaster Relief, Thanks to DoD Contract

One of the very first methods of large-scale 3D printing that the world witnessed was the technology of Contour Crafting Corporation, which uses large but lightweight robotic 3D printers to quickly put down layers of building material in order to rapidly create entire buildings onsite in just days.

Last week, we learned that the US Department of Defense (DoD) had recently awarded California-based Contour Crafting a $3 million research and development contract, effective July 25th, 2018, in the large-scale, construction 3D printing domain. Contour Crafting will use this Rapid Innovation Fund (RIF) to build a concrete 3D printer for the purposes of Rapid Response Construction – quickly constructing buildings for disaster relief, an application that often makes use of 3D printing.

According to the company’s website, “The outcome of this funded R&D program is expected to be a technology which, among other applications, will effectively respond to disaster relief situations with expedient, safe and sustainable structures and buildings.”

The RIF was awarded to Contour Crafting based on its proposal, titled “Autonomous Construction Equipment and Sensing (ACES).” I assume this ACES is not to be mistaken for the US Army’s other ACES program, but as the location on the Federal Business Opportunities page is listed as CERL in Champaign, Illinois, one can’t be too sure.

Regardless, this contract award to Contour Crafting confirms that the DoD is interested in seeking outside help for its construction 3D printing goals, as opposed to just keeping things in-house…never a bad idea.

Speaking of construction 3D printing goals, Contour Crafting is on a mission to commercialize disruptive construction technologies, and this funding award from the DoD should definitely help the company on its way to achieving it.

In 2015, Dr. Behrokh Khoshnevis, who developed the company’s Contour Crafting technology at the University of Southern California and is its CEO and founder, predicted during an interview with 3DPrint.com that 3D printed homes would be widespread within five years. While the 3D printed housing sector is certainly hard at work, we are definitely not there yet. However, 3D printed construction technology does seem to be the perfect answer for smaller structures, like an army barracks and emergency housing, so it’s smart to focus on these while continuing to build up the technology until it’s ready.

While I did not learn too much more about the company’s newly awarded DoD contract, perhaps due to a non-disclosure agreement or something similar, Dr. Khoshnevis was kind enough to answer some questions for me in regards to Contour Crafting’s construction 3D printing technology, as well as the company’s plans for the future.

How does Contour Crafting’s technology compare to other construction 3D printing?

Contour Crafting Transformational Impact

“As the attached [sic] chart (published by an independent Dutch firm) shows, Contour Crafting is the pioneering technology in large scale 3D printing. Over the last 23 years we have developed a large set of related technologies in practically all related subfields including large-scale robotics, material delivery systems, and materials with numerous patented inventions in each subfield. We have conducted research in various application domains including building construction, infrastructure construction and planetary construction. In most fields of our activities no other 3D printing group or company is active so I have no basis for comparison in those fields.”

What do you think the future of 3D printing buildings will be like?

“I think construction by 3D printing will gradually gain popularity but we should not expect that this approach will become the dominant way of building construction. Frist, 3D printing can at best only build the building shell. There is much more to a building than just the shell, which encompasses about 1/3 of the building cost. Second, many buildings will continue to be built with stick frame, steel, etc. and 3D printing is not likely to make any of these alternative approaches obsolete.”

What kind of structures are ideal for 3D printing?

Dr. Behrokh Khoshnevis

“Given that so far the economic attractiveness of construction by 3D printing is still unproven, the only ideal application remains to be construction of buildings that have exotic features, primarily curved walls, which would be potentially more expensive to build by manual methods. In case of concrete printing, even curvatures are limited to 2.5D features, thus giving an upper hand to manual methods over 3d printing approach.”

What are the next steps for your company?

“CC Corp is currently pursuing both construction and non-construction application domains. The latter has the main advantage of not being subject to regulatory restrictions and the complex and potentially costly process of obtaining approval of regulatory authorities for conformance to building codes, which incidentally is different for different localities because of varying factors such as extent of seismic activities and climatic conditions.

“In the field of construction we are advancing more cautiously as we are exploring potential implementation problems and solutions. We are doing many experimentations in-house and are preparing for some field tests as well.

“We have maintained our interest in the field of planetary construction as our prior accomplishments in the field, which include two NASA international competition Grand Prizes, have been noteworthy. We are developing new technologies for in-situ material usage for construction of a variety of useful infrastructure elements such as landing pads, blast protection walls, shade walls, radiation shielding walls, hangars, and roads.”

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3D Printing News Briefs: August 10, 2018

We’ve got some business news to start things off with in today’s 3D Printing News Briefs, followed by a little research and a really cool 3D printed costume. The Department of Defense has awarded a contract to Contour Crafting, and Sutrue is celebrating its tenth anniversary. Facebook has made the decision to ban blueprints for 3D printed guns, and a Siggraph paper takes an in-depth look into near-eye displays. Finally, several companies helped the non-profit organization Magic Wheelchair make a really cool 3D printed wheelchair costume for a big Star Wars fan.

Contour Crafting Receives Department of Defense Contract

One of the first methods of large-scale 3D printing, Contour Crafting, uses large but lightweight robotic 3D printers, which can quickly put down layers of building material to rapidly create entire buildings onsite in just days. The California-based corporation itself is on a mission to commercialize disruptive construction technologies, and we recently learned that the US Department of Defense (DoD) has awarded Contour Crafting a $3 million research and development contract to build a concrete 3D printer for the purposes of building construction for disaster relief.

According to the company’s website , “Effective 25 JUL 2018, the Department of Defense has awarded Contour Crafting Corporation with a Rapid Innovation Fund contract in the domain of large and construction scale 3D printing. The outcome of this funded R&D program is expected to be a technology which, among other applications, will effectively respond to disaster relief situations with expedient, safe and sustainable structures and buildings.”

This information confirms that the DoD is not putting all of its eggs into one basket, so to speak, and is seeking outside help for its construction 3D printing goals.

Sutrue Celebrates Ten Years

Medical device startup Sutrue first started working on a 3D printed suture stitching device to help prevent needle stick injuries back in 2014, and became the first company to successfully 3D print a suture device. But Sutrue’s story actually began back in August of 2008, when its founder Alex Berry was stuck at home with a broken ankle and watched a documentary that provided some insight into robotic suturing. In an effort to keep busy during his recovery, Berry, who had some basic CAD knowledge, got to work.

After moving to the UK, Berry officially started Sutrue in 2012, meeting some influential people along the way who helped him get closer to achieving his goal of creating a 3D printed suture device. The startup completed a £30,000 crowdfunding campaign in 2014, submitted another patent, developed a few mutually beneficial relationships with other companies, and secured further funding for continued device development. Now, Sutrue is celebrating the 10th anniversary of Berry’s initial idea.

The startup wrote in a post, “It’s been ten years of ups and downs, filled with much uncertainty particularly in the first five years in which Berry didn’t even know for sure that the device would work. He has maintained the progression of the device through having a healthy dose of insanity, extreme resourcefulness, and an inquiring and problem-solving mind. He’s gone against many societal norms to have created two working prototypes of his automated suturing device – the robotic and the handheld, but as the route to market becomes closer and closer, he’s glad to have fought against the odds to see the project through to completion.”

Facebook Bans 3D Printed Gun Blueprints

Gun with 3D printed parts. [Image: CNET]

There’s been an increased amount of conversation on the topic of 3D printed guns recently, after news broke of a settlement between the US State Department and Texas open source 3D printed gun designer Defense Distributed, run by Cody Wilson. The settlement states that Wilson and his non-profit organization can publish files, plans, and 3D drawings of guns in any form, and are also exempted from export restrictions; additionally, the government will be paying nearly $40,000 of Wilson’s legal fees. This means that people who weren’t legally able to purchase firearms before, such as felons and domestic abusers, can 3D print their own guns without serial numbers. As you can imagine, many are not happy with this decision. This week, Facebook, the world’s largest social network, said that it will ban any websites that host and share blueprints of 3D printed guns, though the designs have already been available online for years.

According to BuzzFeed News, a Facebook spokesperson said, “Sharing instructions on how to print firearms using 3D printers is not allowed under our Community Standards. In line with our policies, we are removing this content from Facebook.”

MSN reports that Facebook did not “immediately respond to a request for comment regarding the Ghost Gunner” 3D printed gun.

Siggraph Paper on Optical Design for Augmented Reality Near Eye Displays

This year’s annual conference on computer graphics, SIGGRAPH 2018, starts this Sunday, August 12th, in Vancouver. One of the papers published for the conference, titled “Steerable application-adaptive near eye displays,” discusses see-through near eye displays (NED), which are currently being used in the Hololens, among other things. According to the Stanford Computational Imaging Lab, most NEDs work by using a stereoscopic image pair to optically drive the visual system’s vergence state to “arbitrary distances,” but drives the focus (accommodation) state towards a fixed distance.

The technology is a bit of a long shot, due to people getting motion sickness or their eyes getting tired, but if we can get it to work, I bet every movie theatre in the world will employ it.

The abstract of the paper reads, “The design challenges of see-through near-eye displays can be mitigated by specializing an augmented reality device for a particular application. We present a novel optical design for augmented reality near-eye displays exploiting 3D stereolithography printing techniques to achieve similar characteristics to progressive prescription binoculars. We propose to manufacture inter-changeable optical components using 3D printing, leading to arbitrary shaped static projection screen surfaces that are adaptive to the targeted applications. We identify a computational optical design methodology to generate various optical components accordingly, leading to small compute and power demands. To this end, we introduce our augmented reality prototype with a moderate form-factor, large field of view. We have also presented that our prototype is promising high resolutions for a foveation technique using a moving lens in front of a projection system. We believe our display technique provides a gate-way to application-adaptive, easily replicable, customizable, and cost-effective near-eye display designs.”

Co-authors of the paper are NVIDIA Corporation‘s Kishore Rathinavel, Praneeth Chakravarthula, Kaan Akşit, Josef Spjut, Ben Boudaoud, Turner Whitted, David Luebke, and Henry Fuchs from UNC Chapel Hill.

3D Printed Star Wars Wheelchair Costume

Here’s something fun and heartwarming to kick off your weekend – non-profit organization Magic Wheelchair, which makes free, bespoke wheelchair costumes for kids, created a 3D printed Poe Dameron X-Wing Fighter wheelchair costume for a 13-year-old, wheelchair-bound Star Wars fan named Vedant Singhania to wear at last month’s Comic-Con International. Project partners included Pixologic, which used its ZBrush digital sculpting software to provide the design and modeling work, and Dangling Carrot Creative, which used the high print speeds of the Massivit 1800 3D printer to make 50 separate costume pieces in a little over two weeks. Massivit also donated 3D printing materials, and Monster City Studios assembled the large wheelchair costume.

“We connected with Magic Wheelchair because we knew our technology and modelling expertise could assist them with the fantastic work they are doing for children in wheelchairs,” said Pixologic’s 3D Product Development Manager Paul Gaboury. “After we designed the costume, Dangling Carrot Creative was the final piece to the puzzle. The company allowed us to 3D print life-size to help remove the need for molds or casting which saves substantial time and money.”

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Live Demonstration of ACES Concrete 3D Printing Technology at CERL to 3D Print Barracks: Part 2

One half of the 3D Printed Strcture.

I was recently invited to the US Army’s Engineer Research and Development Center’s (ERDC) Construction Engineering Research Laboratory (CERL) in Illinois to see a live demonstration of its Automated Construction of Expeditionary Structures (ACES) technology. Last year, the US Army used ACES to 3D print a complete barracks, or B-Hut, in 21.5 hours with the Army’s patented concrete mixture.

Having only seen still images and video of this unique technology, I knew I couldn’t pass up the opportunity to see a 512 square foot barracks 3D printed live in front of my very eyes within 24 hours. So yesterday afternoon, I hopped in my car for the roughly four-hour drive out west to Champaign.

A closer look at a completed section.

A closer look at a completed section.

The goal for this ACES demonstration is to successfully 3D print the exterior concrete walls of a 8 foot building in 24 hours. While the ACES team and its project partner, Chicago-based architectural and engineering firm Skidmore, Owings, and Merrill (SOM), are both onsite, Marines from the 1st Marine Expeditionary Force are running the equipment; obviously, if the project is successful and this technology is able to be deployed overseas to our troops in the future, they will be the ones actually 3D printing the structures.

Benton Johnson, PE, SE, the Associate Director at SOM, told me yesterday that the Marines were briefed on the ACES technology and equipment via conference call and email. From the looks of things, they seemed to have gotten the hang of everything – preparing and mixing the materials, running the computer, cleaning up the printed layers by hand and clearing away material from the bolts, etc. Johnson pointed out that the main coder of the project was onsite, but only to offer assistance if needed.

A close up of the nozzle 3D printing the barracks. Image Sarah Saunders.

“I think part of this is a learning curve, because all the Marines that were out there operating the machinery had never seen this or touched it before,” Captain Matt Friedell told me.

“But they took to it, and once they learned it, they started to get in their groove and really pick up the pace. And we knew when we were going to attempt this that it was going to be a challenge.”

Obviously, there were a few glitches, as people rarely get the hang of new technology perfectly the first time out. The barracks is being 3D printed in two halves, and at one point the Marine running the computer accidentally sent the nozzle over to the side that wasn’t being worked on yet; later, when steel dowels were being added for initial reinforcement to the first 18″ or so of 3D printed concrete, work began on the wrong side. But none of this seemed to slow the process down.

However, as I mentioned yesterday, things did not start off swimmingly. Program manager Michael Case, PhD, told me that one of the issues with concrete is evaporation drying. So when the forecast showed rain today, the start time of the demonstration was moved up a few hours, only to halt again pretty quickly. Dr. Case explained that the material used at the Fort Leonard Wood demonstration a few months ago was sharper and more angular than it is here at CERL, and tore up the inside of the pump.

By the time the team finished replacing the pump and working the kinks out of the hose, it was almost the original start time of 5 pm. it looked like things were going to start moving, until the material didn’t extrude properly and some team members removed the nozzle to find that a rock inside was jamming things up. When the concrete finally started to print, the material mixture had to be adjusted after the first layer because it was too sloppy. But once this was fixed, things really took off, and work continued through the night, with very few clogs.

Spoiler alert: when I arrived back at CERL this morning, I learned that the team would not be able to make its original deadline of 24 hours. Dr. Case explained that “a big part of this is to figure out how long you can continuously use the equipment.”

“So we learned a lot about things…If you operate this type of concrete printing equipment long enough, you have to stop and service some of the equipment.”

Dr. Case said that if you don’t clean out the equipment, you can get concrete curing inside of the pump, and that it will eventually shut down, which caused some delays overnight. So by about 9 am this morning, the team had nearly completed the first half of the structure, and was planning on taking a few hours of much-needed rest before starting in on the second half.

While the ACES team won’t make the original goal of a continuous 24 hour print, the work they’ve completed and will continue throughout the rest of the day, is extremely impressive. Capt. Friedell told me as I was leaving CERL that he was certain this project is the tallest continuous 3D print in the US.

Stay tuned to 3DPrint.com for a more in-depth look at my visit to CERL this week! So far it has been very exciting to be able to have unfettered access to the site and to have been given access to all of the people involved. Issues with extrusion, rain and the weather that this team had actually made me question more the validity of some “3D printing a house in a day” claims. What this team ancountered were real-life challenges brought on by equipment and the weather that slowed them down. I think that CERL’s effort, undertaken with a journalist present, was much more transparent, open and honest than the commercial house printing initiatives who somehow always tell us after the fact the great feats that they’ve accomplished. I can now really see the value that house 3D printing could have for the Marine Corps, Army and for civilian use. Most of all I’m grateful that I got an up close and personal look at what it actually takes to 3D print a structure.

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[Images: Sarah Saunders for 3DPrint.com]