PROLOGUE

Additive Manufacturing (AM) is quickly becoming the tour-de-force in our industrial progression. Using 3D printing and other state of the art technologies, we are not only enabling smart manufacturing, but also providing for customized products at scale. Utilizing it and other technologies like AI/ML, Blockchain, IoT, and AR/VR and other Mixed and Hybrid reality techniques, we at Numorpho Cybernetic Systems (NUMO) are harmonizing the bind between the different silos of the product lifecycle – business processes, innovation, production, and marketing and sell.

OVERVIEW

Innovation and complex product design needs prototyping. One of the key enablers of this growth cycle is the use of 3D printing in prototyping, enabling a new and faster product development process where the product itself is designed in a digital environment and then printed, assembled and tested to validate the design hypotheses. 3D printing enables a new product development process, where the product is designed in a digital environment and then printed, assembled, and tested to validate the design hypotheses. We are now at the point where we can see how this vision is becoming a reality. The costs of 3D printing are coming down rapidly – not just the machine and the material but also the time that is necessary to learn how to use it.

Using 3D printing techniques is changing the way prototypes are being made, challenging the very core of what it means to create. Born not built was the central theme of that article where we laid out the formation of new products and services as a growth cycle from morning (AM), through afternoon and in the evening giving rise to making personalized products produced in large scale – what we termed custom manufactory.

In this article we take a short hiatus to reflect on our forays into 3D printing and such – FDM, SLA and SLS, and how we anticipate helping in building the future of electric mobility, infrastructure, smart cities and even inter-planetary (space) travel.

We will showcase some of our experiments with 3D printing using different techniques to showcase the pros and cons so that we assimilate it into our knowledgebase for building real products.

ADDITIVE MANUFACTURING TECHNOLOGIES

Fused Deposition Modeling (FDM) is a 3D printing process that uses a continuous filament of a thermoplastic material. Filament is fed from a large spool through a moving, heated printer extruder head, and is deposited on the growing work. The print head is moved under computer control to define the printed shape. Usually, the head moves in two dimensions to deposit one horizontal plane, or layer, at a time; the work or the print head is then moved vertically by a small amount to begin a new layer. The speed of the extruder head may also be controlled to stop and start deposition and form an interrupted plane without stringing or dribbling between sections. The 3D printer heads, or 3D printer extruder is a part in material extrusion additive manufacturing responsible for raw material melting and forming it into a continuous profile. A wide variety of filament materials are extruded, including thermoplastics such as acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polyethylene terephthalate glycol (PETG), polyethylene terephtathalate (PET), high-impact polystyrene (HIPS), thermoplastic polyurethane (TPU) and aliphatic polyamides (nylon). FDM begins with a software process which processes an STL file (STereoLithography file format), mathematically slicing and orienting the model for the build process. If required, support structures may be generated.

Stereolithography (SLA) belongs to a family of AM technologies known as vat photopolymerization, commonly known as resin 3D printing. These machines are all built around the same principle, using a light source—a laser or projector—to cure liquid resin into hardened plastic. The main physical differentiation lies in the arrangement of the core components, such as the light source, the build platform, and the resin tank. SLA 3D printers use light-reactive thermoset materials called “resin.” When SLA resins are exposed to certain wavelengths of light, short molecular chains join together, polymerizing monomers and oligomers into solidified rigid or flexible geometries. SLA parts have the highest resolution and accuracy, the sharpest details, and the smoothest surface finishes of all 3D printing technologies, but the main benefit of the stereolithography lies in its versatility. Material manufacturers have created innovative SLA resin formulations with a wide range of optical, mechanical, and thermal properties to match those of standard, engineering, and industrial thermoplastics.

Selective laser sintering (SLS) 3D printing is trusted by engineers and manufacturers across different industries for its ability to produce strong, functional parts. SLS is an AM technology that uses a high-power laser to sinter small particles of polymer powder (nylon in this case) into a solid structure based on a 3D model. As the unfused powder supports the part during printing, there’s no need for dedicated support structures. This makes SLS ideal for complex geometries, including interior features, undercuts, thin walls, and negative features.

OUR FORAYS

Make no little plans and thinking big laid the foundations of our philosophy on architecting the future where we envisioned that old paradigm must give way to something more life-like–more able to create resilience and sustainability, and more able to serve the real needs of human beings.

LEARNING BY CHALLENGES

CHALLENGE 1 – TETRAHEDRON, SPHERE and CUBE

Given one dimension – the side of the length of the triangle of the tetrahedron, is it possible to use CAD to parametrically model and print the 3 shapes so that the yellow tetrahedron would fit inside the blue sphere which would be boxed in the red cube?

Ideation

In 2D, the 3 Bauhaus objects – triangle, circle and square can be represented by the adjoining diagram, colored in its characteristic scheme – yellow triangle, blue circle and red square.

If the triangle had side “a”, the height of the triangle would b:

h = a*sin(60) = sqrt(3)/2*a

since the centroid of the triangle is the center of the circle at 1/3 above the base:

(r)squared = (a/2)squared + (a/3*sqrt(3)/2)squared = (a)squared*(1/4+1/12)

(r)squared = (a)squared*(1/3)

r = a/sqrt(3)

Thus the side of the square = 2*r = 2*a/sqrt(3).

The above formulation gives the basis for constructing the challenge statement 1 in 2D.

Solutioning

Extending similar formulations in 3D adds the implication of the third dimension into the solutioning, which although not difficult, can be simplified by utilizing tools available in CAD software. Parametric design is the basis for CAD software where we can create scaled models of actual products to test them for appropriateness before building it to scale.

By parametrically changing the size of the triangle to 50 mm, we could make all of the shapes fit into one print albeit it took 30.5 hrs to print all the objects and its associated support materials:

CHALLENGE 2 – CONE, PYRAMID and CYLINDER
Given one dimension – the base radius of a cone, is it possible to use CAD to parametrically model and print the 3 shapes so that the yellow cone would fit inside the red pyramid which would be enclosed by the cylinder? Note that the height of the object would be determined by the side of the pyramid – we are assuming the pyramid to have equilateral  triangle sides. To make them closed shapes, a mirror image of these objects needs to be created to have a bi-conic object, an octahedron and an extended cylinder.

Ideation

The adjacent diagram shows the base of the 3 objects – the yellow cone, enclosed by the red pyramid that is enclosed by the blue cylinder. Based on the problem statement of the challenge we notice that the side of the pyramid is twice the radius of the cone.

Half the diagonal of the base of the pyramid is given by:

(d)squared = 2*(r)squared

also, the height of the pyramid is given by the equation:

(d)squared + (h)squared) = (2r)squared

(h)squared = 4*(r)squared – 2*(r)squared

(h)squared = 2*(r)squared

The above formulation gives the basis for constructing the base of the challenge statement 2 and the formula for the height of the object.

Solutioning

We start of by defining the side of the triangle and square base of the pyramid as the basis for the construction.

Rather than use Pythagoras’ IP, is there an easier way to solve the problem using CAD – What if a 2D shape was constructed using a square and four equilateral triangles surrounding it? We could then fold the triangles up to create the required pyramid. Egyptians might get really upset though!

CHALLENGE 3 – A THREE DIMENSIONAL YIN YANG
A two dimensional Yin Yang shape divides the circle into two equal halves. The goal of this challenge is to map the Yin Yang to the surface of the sphere to in effect create the seam line of a baseball, tennis ball or the curves in a basketball, and effectively print them in 3D so that they fit into each other.

Ideation

In Ancient Chinese philosophy, yin and yang (Chinese: 陰陽 yīnyáng pronounced [ín jǎŋ], lit. “bright-black”, “positive-negative”) is a concept of dualism, describing how obviously opposite or contrary forces may actually be complementary, interconnected, and interdependent in the natural world, and how they may give rise to each other as they interrelate to one another. In Chinese cosmology, the universe creates itself out of a primary chaos of material energy, organized into the cycles of Yin and Yang and formed into objects and lives. Yin is the receptive and Yang the active principle, seen in all forms of change and difference such as the annual cycle (winter and summer), the landscape (north-facing shade and south-facing brightness), sexual coupling (female and male), the formation of both men and women as characters and sociopolitical history (disorder and order).

The principle of yin and yang is represented by the Taijitu (literally “Diagram of the Supreme Ultimate”). The term is commonly used to mean the simple “divided circle” form, but may refer to any of several schematic diagrams representing these principles, such as the swastika, common to Hinduism, Buddhism, and Jainism. Similar symbols have also appeared in other cultures, such as in Celtic art and Roman shield markings.

In this symbol the two tear drops swirl to represent the conversion of yin to yang and yang to yin. This is seen when a ball is thrown into the air with a yang velocity then converts to a yin velocity to fall back to earth. The two tear drops are opposite in direction to each other to show that as one increases the other decreases. The dot of the opposite field in the tear drop shows that there is always yin within yang and always yang within yin.

The adjacent Taichi Yin Yang shape was created by intersection of multiple circular shapes with the outer circle being twice the middle which is twice the size of the innermost eye. This is a great exercise in the use of intersecting shapes in Powerpoint.

For the purpose of the challenge we will exclude the innermost eyes for recreating the “ball” shapes in two primary colors – blue and red as shown in the adjacent diagram, not the effervescent Pepsi symbol!

The goal of this exercise is to enable the creation of the curve in 3D that conforms to the shape of a baseball, tennis ball or the basketball and be able to 3D print it in two colors (blue-red or black-white)

Baseball	Tennis Ball	Basketball

Solutioning – WELCOME TO THE BALL GAME?

Complicated formulations exist to define the template of the curve of the baseball in two dimensions that can be then slapped onto the surface of a ball in two anti-podal directions to get the seam, as shown in the diagram. A thorough treatment of the designing the baseball is at this website:

Click to access DesigningBaseballCover.pdf

The goal of the solutioning of this is to simplify the procedure and utilize the spline feature in CAD to carve out the curve that would lie on top of the sphere and equally divide it into two halves.

Technique: An equator divides a sphere into two equal hemispheres. We create four control points on the equator at 0 (1), 90 (2), 180 (3) and 270 (4) degrees longitude, and move point 1 & 3 up to lets say the 45 degree latitude and points 2 and 4 down to the 45 degree latitude (down under!). Now it is a simple matter of creating a b-spline that connects these four control points and moves along the surface of the sphere. By changing the latitude and the definition of the b-spline the different curves of the 3 balls can be achieved.

PRINT SOLUTIONS

PLA Filament – PLA also known as polylactic acid or polylactide, is a thermoplastic made from renewable resources such as corn starch, tapioca roots or sugar cane, unlike other industrial materials made primarily from petroleum.

PLA filament is by far the most popular material used in FDM 3D printing, and there’s a good reason for that. It comes in many shades and styles, making it ideal for a wide range of applications. Whether you’re looking for vibrant colors or unique blends, it’s an easy-to-use and aesthetically pleasing material.

The diversity of blends, colors, and properties of PLA filament is seemingly endless.

TPU Filament – Thermoplastic Polyurethane (TPU material) is a flexible, abrasion resistant thermoplastic. It’s being used in a number of manufacturing processes for both consumer and industrial use. In certain blends it can become very soft, but TPU material offers many benefits and features. 3D printed parts with TPU are durable and have the ability to withstand ambient temperatures of up to 80 degrees Celsius.

TPU filament is abrasion resistant, can withstand impacts and is resistant to many chemicals. Its versatile and used in many different industries. There are different versions of TPU material but in the main it can be classed as two types: Polyether Polyurethane and Polyester Polyurethane, with both having different characteristics that can be suited to a specific need.

ABS Filament – Acrylonitrile Butadiene Styrene (ABS) is an opaque thermoplastic and amorphous polymer. ABS is most commonly polymerized through the process of emulsion (the mixture of multiple products that don’t typically combine into a single product). It is important to note that because ABS is a thermoplastic material, it can be easily recycled, as mentioned above. This means that a common way of producing ABS plastic is from other ABS plastic (i.e. making ABS from ABS).

In comparison to PLA filament, ABS plastic is less “brittle” and more “ductile.” It can also be post-processed with acetone to provide a glossy finish. When 3D printing with ABS filament, a heated printing surface is recommended, as ABS plastic will contract when cooled leading to warped parts. ABS filament is available in both 1.75mm and 3mm diameter sizes.

We’ll rebuild this city, albeit a parody on an erstwhile song by Jefferson Starship, is our plan for the future of electric mobility, infrastructure, and transportation. The very concept of smart cities is fundamentally rooted in the thinking that smart cities will be connected. In this scenario, people want to live in a more connected world. They want to be able to communicate, communicate more efficiently, communicate more often, etc. The next logical step is to improve connectivity, which requires an informed strategy for transit and roads that is integrated with urban design. The above showcases a scaled model of Chicago FDM printed using a multi-colored filament on a 10inchx10inch plate on a Lultzbot that will serve to contextualize and highlight the plan we have for city-scaping the future of Chicago.

The chess pieces showcased above shows the Moai warriors printed in 3 different ways from the same STL CAD file – Brothers from different mothers – SLS Nylon powder laser fused white Moais vs SLA Resin UV printed red warriors (Anycubic Photon Mono SE) vs FDM filament printed orange men (Anycubic 4Max Pro 2.0)!

SUMMARY

The Additive Manufacturing process is much more than just using a 3D printer – it is a complete digital factory, where the product is designed digitally, printed digitally, assembled digitally, and tested digitally. The digital factory is the key enabler for a new product development process and for custom manufactory, where the product is designed in a digital environment and then printed, assembled, and tested based on customer preferences. AM will also be a game changer for supply chain in that we will be less reliant on offshore manufacturing and the logistics of shipping when products and parts can be manufactured on-premises or locally with speed and reliability.

We have moved beyond artifacts and inventions. In today’s world we need to link and intertwine heterogeneous systems, make them interoperable, aggregate data, and provide pertinent information at the right time and the right place with flexibility and ease of use. We also look at AM to be the precursor of building sustainable and resilient infrastructures of the future as showcased in our Smart Cities initiative to re-emphasize on our theme of Everything Connected.

NI+IN UCHIL Founder, CEO & Technical Evangelist

nitin.uchil@numorpho.com