EXLAB Digital Furniture Fabrication 2015 - By JOSHUA STELLINI

EX-LAB

DIGITAL FURNITURE FABRICATION SEMESTER ONE 2015

JOINTS

RESEARCH FILE

BY JOSHUA STELLINI

FOREWORD This research file is a collection of precedents and sources of inspiration found while researching for the graduate architecture subject EXLAB-Digital Furniture Fabrication at the University of Melbourne. The subect involves having a selected group of students designing and constructing their own piece of furniture.

These furniture pieces aim to exploit the potentials of digital fabrication technologies such as lasercutters, CNC routers and 3D printers in combination with software such as Rhinocerous 3D and Grasshopper.

The projects that follow specifically highlight projects which show interesting or unusual joining methods which is in line with my chosen study agenda for this semester. All works are fully cited and can be viewed online by simply clicking on the title of the projects which will redirect to an external URL page.

These URLs were correct as of April 2015.

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CONTENTS LOCK Page: 2

Represents a series of precedence which have qualities of interlocking members in interesting ways.

PRINT Page: 12

Projects which use 3D Printed technology to form unique bespoke joinery elements.

FLEX Page: 20

Precedent projects which use an unconventional system of joining such as flexing, bending or twisting.

NETWORK Page: 26

Research into projects which use interesting networks created by 3D printing or other material hybrids.

MATERIALS & MACHINES Page: 32

Research into material choices and fabrication technologies.

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LOCK

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JOIN SERIES - DING3000 with Konstantin Slawinsk (2010, 2011)

Project: The JOIN cutlery set is an interesting example of product design which uses the joint as a key aesthetic feature. The idea was inspired by an ancient Japanese puzzle in which three interlocking pieces join to form a ‘devils knot’. This cutlery set was such a success it was followed up with the DING table which uses the same enigmatic principles as the cutlery set and achieves a mysterious joint which fits together without any tools or traditional fixings.

Relevance: Members joining in three directions add an increased layer of complexity, especially when the join is so seamless as it is in this case. These projects would both be relatively cheap and efficient to manufacture and distribute being comprised of flat pieces.

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Puzzle Furniture- PRAKTRIK Studio

Project: Based on burr puzzles Architect Petar Zaharinov has created a line of what he calls ‘puzzle furniture’ namely in the form of dining and coffee tables. The tables have no fixing mechanisms and simply slide into each other in a predefined order. In the absence of traditional fixings the system relies solely on the connections between elements for strength.

Relevance: Having made smaller scale models of both these tables, I can appreciate the strength that can be achieved by interlocking multiple components, even without the use of traditional fixings. Many of these tables are made up of identical segments, making production and manufacture a relatively simple process.

Application: I think the greatest strength of both the puzzle furniture and the DING projects are their ability to disassemble and reassemble, which allows the furniture to be portable and easy to store if not in use. There is something quite nice about these projects in which the joint becomes the focal point of the design. Also the sense of mystery about the way it is constructed is quite appealing. One issue with this puzzle approach however, is developing a unique puzzle on my own, which will prove to be extremely difficult as they are often based on mathematics and complex geometries which will take a long time to develop to any sophisticated level of detail.

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Chidori Furniture (below) - Kengo Kuma and Associates (2011) GC Prostho Museum Research Center (left) - Kengo Kuma and Associates (2012) Project: Based on the system of chidori, an ancient Japanese toy, Kengo Kuma designed the chidori line of furniture. The members of the table feature a series of very specific cuts which allow three pieces to be combined together and assembled seamlessly. The whole system can be extended indefinitely by merely twisting the sticks, without any nails or metal fittings. Kengo Kuma applied this same chidori system to his GC Prostho Museum (left), proving that the joints are even strong enough to expand to a building scale.

Relevance: Early design explorations lead me to this project as a precedent due to its seamless connections and its ability to connect multiple intersecting members. Contrary to the previous projects, the joint here does not become the focus, but is hidden, with the system as a whole becoming the aesthetic feature of the design.

Application: I find the aesthetic of the GC Prostho Museum quite interesting particularly for the semitransparent quality it has when illuminated as seen in the photographs. The idea of a system of joints amalgamating to form a larger whole is quite intriguing particularly if combined with customised 3D printed or CNC cut components.

While I aesthetically and tectonically admire the seamless joints, it is a shame that the intricacy and skill involved in its creation is lost when the architecture/furniture is assembled. I tend to prefer an approach where the join is displayed and appreciated rather than hidden from view.

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Quadror - Studio Dror (2007) Project: Architect Dror Benshetrit, has invented Quadror, a self locking structural joining system. While initially fascinated with the geometry of Quadror, the architect soon discovered the innate strength the interlocking geometry is capable of. The system has various applications, such as a table but can also be expanded to provide structural solutions for buildings, highways and disaster relief.

The quadror uses four identical L shaped pieces with chamfered edges that are fixed together in key locations. The geometry allows for the pieces to slide over one another and lock into place, forming a strong modular joint that is able to be collapsed.

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Relevance: The idea of joints which move have always been an area of interest and potential avenue of exploration for my design. This precedent is by far one of the most simple and elegant solutions in this regard. Having CNC cut a Quadror I understood this project more and more as a study on geometry rather than strictly jointing, however the Quadror only works because of a harmony between the two. The interlocking aspect of the design and enormous structural strength are obviously interesting outcomes of the design however for me the most intriguing aspect of the Quadror is its ability to change.

Materialise - Studio Dror (2011) Project: Also by Studio Dror is the Materialise lamp. It is essentially created by using the geometry of Quadror and applying it in 3 dimensions. The lamp was created as a single piece using 3D printing and is able to expand from a completely flattened position to a volumetric cube with an intricate display of light and shadow.

Relevance: Prior to finding this project, I had only thought of using 3D printers to create unique bespoke elements that would replace traditional joinery elements. This precedent highlights the potentials of 3D printing that, when combined with a smart geometrical solution can produce an intricate web of joints which act together as an entire system.

Application: The Quadror’s greatest innovation is its ability to fold from a flat geometry into a structure able to support weight. While I think such a system will be very difficult to improve upon, there are lessons to be learnt in the way that a system of joints in combination with innovative geometries can allow objects to fold and expand. Once again I would really like to incorporate the idea of portability into my project and both Quadror and the Materialise lamp are a very good example of how a system of joints allow for a folding mechanism. The fact that such a complex geometry is able to be formed from one single 3D printed part is also an idea I would like to explore further.

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New Milan Trade Fair - Studio Fuksas (2012) Project: The Milan Trade Fair is a gridshell designed by studio Fuksas.

The giant glass clad canopy was designed to house exhibition halls, restaurants and auditoriums. The gridshell uses straight members and planar glass panels intersecting at various nodes to create a free-form surface.

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Relevance: This project is interesting for a number of reasons particularly from an engineering and structural optimisation perspective but for the purposes of this research the node have become the primary focus of investigation.

Node Plan

The node manufacturer MERO has developed a joint to accommodate for changing angles of members to allow for a free-form surface to be developed from straight members.

Because of the varying angles created by the gridshell, no two nodes are the same and so digital fabrication was necessary to fabricate unique elements. The nodes themselves are made in three parts which in section have varying angles which are CNC cut to accommodate the intersecting members. The three pieces are then clamped together and the members bolted on.

This shows how small incremental changes to one element such as a joint can affect an entire system.

Node Section

Application: Developing a joint which is mass customised through digital fabrication processes such as this has a variety of applications.

A single joint could be used as the centre piece of the design with the varying angles CNC cut to accommodate the members. Alternatively a whole series of these joints could be 3D printed or manufactured digitally to achieve a free-form surface as in the case of this precedent. Once again here we see how a series of joints can be considered as a network.

Top Piece Top Piece

Middle Piece Bottom Piece

Node Perspective

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PRINT

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Screw Stool - Hans Van Sinderen (2014)

Project: The screw stool is designed as a flat pack furniture piece with a twist (no pun intended). The design incorporates a screw fixing into the project in a unique and exciting way. A screw like fastener is divided into three pieces. Each leg of the screw stool makes up one third of the final screw fixing which once combined together are inserted into the seat which acts like a nut joining the elements together.

Relevance: One of the most interesting things about this project is the way it is fabricated. A 3D printed part was used to create a mould which allowed the pieces to be rapidly reproduced with precision. It is also quite innovative in its joining method which reinterprets an old fixing technique by segmenting the join into three parts which then come together as a whole.

Application: There is a sense of harmony as all pieces of the stool are required for assembly and if even just one is removed the entire system fails. This relationship between elements that combine to make a greater whole may become essential to the my design, particularly given the limitations on 3D print area.

The idea of casting a 3D printed part had not been considered before looking into this piece but makes logical sense if the design is to be mass produced. Despite this I don’t think its an avenue I would like to take further as I would rather explore what 3D printing is really good at which is mass customisation, difference and variation.

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Keystone Series - Studio Minale Maeda (2014)

Project: Presented at the Milan Furniture Fair, Studio Minale-Maeda presented the Keystones series of furniture. Using standardised wooden parts, the designers fabricated a series of ‘keystones’ which are 3D printed joinery elements. In theory these 3D printed joinery elements could be downloaded, printed and the entire furniture piece could be reproduced at home.

Relevance: The 3D printing industry has been claiming to revolutionise the world and these designs are examples of how this ideology would be put into practice. An entire table is assembled with standardised timber elements and 3D printed joints.

The beauty of these keystones are the fact that they are specifically designed for purpose and take full advantage of 3D printing technology to create bespoke unique parts.

These projects also allow for joinery methods which were not previously possible such as joining together 5 or 6 members intersecting at various angles.

Application: There is great potential for joints with 3D printing as unique components can fulfill a multitude of purposes. It is also useful to consider 3D printed components as they are small and able to be fabricated on the in house 3D printers which have size limitations. These components which are then combined with other elements such as timber rods is preferable over 3D printing entire structures which will take an enormous amount of time effort and resources.

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3D Printed Side Table - Shurly Project: This project was found on instructables a DIY website. The user Shurly provided his/her schematics and Rhino file along with instructions on how to make this side table. It is interesting that it shares so many parallels with Studio Minale Maeda’s work despite being a DIY project.

This shows how 3D printed components may eventually revolutionise the furniture industry. There is also something quite nice about this project as well as keystone which the joint becomes a unifying element and is strongly contrasted against the timber elements.

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Multithread Collection - Clemens Weisshaar & Reed Kram (2012) Project: Kram/Weisshaar have designed a series of furniture pieces which all feature a horizontal surfaces supported by an aluminum frame.

The designers used MULTITHREAD a software they developed to optimise each of their designs based on loading requirements to change the location, size and shapes of the joints. Once the design is finalised the software outputs 3D CAD models of the various joints which are then 3D printed with an Selective Laser Sintering (SLS) metallic powder printer. The joints form a seamless connection acting as a sleeve to which the aluminum members slide on to. The colours associated with each joint are different and are a direct representation of the forces acting within the nodes.

Relevance: Multithread is a great example of the designers taking full advantage of the strengths of 3D Printing. Each joint printed is specifically designed with a specific geometry for a specific location and purpose. No two elements are alike, but with 3D printed components this is not cause for concern as mass cusomised elements are easily produced. The project also touches upon issues of structural optimisation, and even uses a BESO (Bidirectional Evolutionary Optimization) technique in order to help optimise the supports given their orientation and loading.

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Application: Multithread highlights the advantages of using software in combination with material explorations to enhance and enrich the design. Again this is a project in which the joints are optimal solutions given certain parameters, which is an approach well suited to 3D printing and other digital fabrication technologies.

For my project I have thus far been primarily focusing on the physical side of production and in many ways neglecting the power and opportunity softwares such as Rhino and Grasshopper provide to the design process.

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FLEX

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Shrink Wrap Joints - Nicola Zacco (2010)

Project: Graduate student Nicola Zacco has created a furniture line which uses an unconventional joining method. Using shrink plastic, which is traditionally used to protect electrical cabling, the members are tightened by simply heating the plastic and allowing it to cool. The result is a surprisingly strong and rigid connection that wraps around intersections conforming to a variety of shapes and materials.

Relevance: The elegance of this project comes from its simplicity and detail in the notches of the timber members which is brought together with an unconventional fixing mechanism. The shrink wrap is also able to accommodate many different intersections and material types as the plastic will form around the members conforming to their shape. This project also has a nice aesthetic but what is particularly interesting about it is how a material is used in a way it was not truly intended.

Application: The lessons of pushing the boundaries of materials and process can be applied to many aspects of digital fabrication. One of the areas I plan to explore is how the boundaries of 3D printing may be extended in particular how materials such as ABS, a rigid and stiff material might be re imagined and reinterpreted into a flexible and movable components.

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Flexible Joinery - LAB DAG (2011)

Project: Created by Israeli design studio Lab Dag, Flexible Joinery uses an unconventional system of joinery elements. Cast out of silicone these joints become temporary and intuitive fixing devices able to cater to a large number of unorthodox connection types. The silicone has an internal metal skeleton which allow the rods to maintain their shape when twisted into place.

Relevance: This project is interesting because the joint becomes a versatile element within the design that can be used for a number of applications. This is a direct result on the flexible nature of the material which is able to adapt and change to many different situations and geometry types. Relying solely on the friction between the silicone and the members to keep the elements tied in place this project redefines what a typical join can be.

The silicone rods also allow for easy assembly and portability in the design.

Application: Flexible joinery elements are rarely explored in contemporary design projects which usually favour a more permanent rigid connection for increased strength and stability. With the introduction of 3D printing it is now possible to print components which are able to bend or flex. These materials if used creatively can result in unexpected and innovative design responses.

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Elastic Wood Chair - Gil Sheffi (2010) Project: The Elastic Wood Chair aims to explore the potentials of having flexible joints within a traditional timber construction. The chair is fabricated as a flat 2D spread with voids for which the elastic material is cast into. Using a process called overmoulding the two materials are fused together into a watertight seal.

The chair is then removed from the mould and bend into shape and laterally braced with traditional fixings.

Relevance: The elastic wood chair made me reconceptualise what a joint could be and how it could function. In this case, the flexible material acts as an elastic hinge allowing a flat geometry to facilitate 3 Dimensional form. This marriage between two very different material properties finds a harmony and purpose in this project. The dialogue between the hardness of the wood and flexibility of the elastic material lead to an interesting outcome that lends itself quite well to a flat-pack approach and digital fabrication.

Application: This marriage between two very different material properties is something I am aiming to explore in my design quite heavily.

Though I may use timber in the final outcome, I would like to explore this dialogue through 3D Printing with traditional ABS and a more flexible material such as NINJAFLEX. Having joints which are flexible and capable of bending into a predefined shape had not been a consideration previously, however is a relatively unexplored area that I may incorporate into my final design, particularly as it lends itself well for a portable furniture piece.

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NETWORK

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Biomimicry 3D Printed Sofa Seat - Lilian van Daal (2014) Project: This sofa seat explores the potentials of 3D printing entire structures as an alternative to traditional furniture production.

Designed to combat the inefficiencies of recycling furniture the seat was printed in one piece with a biodegradable filament. By looking at various natural sources such as plant cells the designer has developed a detailed understanding of complex geometries and ways they inform structure and bending qualities. In her chair Van Daal utilises the geometry in different ways in order to alter the behavior of the system, where the less dense parts are soft and other areas being more desne, rigid and structural.

Relevance: For the most part, many of the 3D printed precedents presented thus far have used the technology to create components or objects.

Many of these components were recreations of other objects such as screws and brackets. This project is interesting as it is not constrained to reproducing existing objects, but rather uses the 3D printer to create an intricate network of complex geometries based on natural systems, a feat which is unachievable in any other manufacturing process or medium. Despite the designer claiming to be combating inefficiency I would regard this process as extremely inefficient in terms of wasted material, time and resources.

Application: While I don’t particularly admire the aesthetic and not strictly not a joint project per se, what is admirable about this project is the effects achieved through 3D printing complex cellular geometries.

This can be used on an entire furniture piece given a large enough printer, but also on smaller modular sized components which join to create a system. This project also highlighted to me the importance of material testing and persistent prototyping involved to develop a project to such a sophisticated level of detail.

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3D Printed Textiles - Various Designers Project: These 3D printed textile projects use an intricate system of interlocking geometry to emulate the qualities of textiles and fabric. This is achieved by allowing the cells slight movement allowing them to fold over one another and conform to virtually any shape. The flexibility of each section can be different, simply by altering the thickness of the individual cellular units.

Similarly the packing system used is not always uniform and generally relate to curvatures. Tighter curves generally use smaller cells while flatter contours use larger geometries.

Relevance: An interesting characteristic of any system such as this is how small incremental changes on a local level can create different attributes globally. In this case this cellular structure can be manipulated in order to change the opacity, flexibility and stretch properties throughout the garment. These precedents are also quite facinating as they are using what are essentially hard plastics to create soft object, simply by manipulating geometry.

Application: These 3D printed textiles could be expanded upon further with flexible filaments to produces softer qualities that could be used as a form of digital upholstery. Interesting hybrids could be developed when combining these textiles with a more rigid material such as timber. A deep understanding of the relationship between the cells is required in order to manipulate a material such as this, however once understood, these elements could be automatically generated parametrically with packing routines and geometric associations in grasshopper.

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Programmable Table - WoodSkin & Self-Assembly Lab MIT (2015) Project: Unveiled only days ago at Milan Design Week, this precedent is a late addition to this document. Designed as a collaboration between WoodSkin and MIT Self Assembly Lab the Programmable table merges these two exciting fields of research into one project.

The wooden frame was developed using WoodSkin’s patented timber, textile hybrid in which two pieces of timber are sandwiched between a membrane layer. Deep cuts allow hinge like movement allowing the table to pop up from a flat surface.

However the really exciting aspect of this project was developed

by MIT’s Self Assembly Lab. The SAL have been researching into techniques of ‘programming’ logic into materials so they behave in a certain way under certain conditions. In this case they 3D printed directly onto a fabric to develop a membrane with shape memory and retention. The programmable membrane is attached to the base frame and with a slight nudge, the table pops up with minimal human intervention.

Relevance: This innovative field of research is extremely exciting as it paves the way for self assembling flat pack furniture. Flat pack tables can be unpacked from the box and assembled without the need for any fixing mechanisms or tools and then flattened again when not in use. The pop up nature and hybrid material use of this project it really fascinating and shows how different materials when combined together can enhance and compliment one another. The joint in this case is the fabric itself which is material I had not considered using before. The fabrication is also relatively simple with the table cut in 2 dimensions with a CNC machine which is then in filled with the memory fabric.

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Application: While programming a material with logic may prove to be difficult I would like to explore if something like this is possible with 3D printing. 3D printing on fabric is an interesting technique which may be included in the final design. I have also seen potentials with shape retention and memory in the experiments I have done which utilise flexible filaments. Until now I have yet to find a use for these experiments however they share many parallels with this project and may be an avenue to explore further. This project again plays upon the relationship between hard and soft materials which may be something can emulate.

Detail showing WoodSkin’s timber/textile hybrid material in which a layer of fabric is sandwiched between two wooden pieces. This allows the joint to act as a hinge.

The carcass of the Programmable table is CNC milled to reveal the self assembling fabric beneath and to create fold lines for the table.

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MATERIALS & MACHINES

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MATERIAL RESEARCH List of readily available materials easily accessible through FABLAB Timber Plywood

3D PRINTER FILAMENTS ABS

PLA

Acrylonitrile butadiene styrene (ABS) is a common plastic used in many of the objects including Lego. ABS is strong, durable and can also be flexible when printed thinly in certain geometries. It requires a heated bed and controlled environment for 3D printing. It is not very environmentally friendly, and will emit some fumes while printing.

Polylactic Acid (PLA) is a polyester made from natural and renewable materials, most commonly corn starch. PLA is biodegradable and can be used as an alternative to ABS. PLA requires a lower extrusion temperature and becomes a liquid when extruding. PLA is also advantageous as a support material as it dissolved in caustic soda.

It can print finer than ABS and does not require a heated print bed.

WOOD POLYMER

LAY BRICK POLYMER

This is a new experimental filament made from a mix of wood particles and bio-polymers, which can be used to produce items that look like wood or cardboard. After printing it also smells like wood and can be grinded and painted in the same way as wood. The print texture is simply beautiful and it hides print layers nicely, and does not require a heated bed.

This is a new experimental filament made from a mix of powdered chalk and mineral particles and polymers, which can be used produce items that look and feel like stone. After printing it can be sanded to be very smooth, or is rough like stone straight off the bed. If can also be dyes with ink and painted. No heated bed is necessary and it is warp-free.

METALLIC

HEAT/LIGHT CHANGE PLA

This filament available through Bilby is a blend of 80% fine Bronze particles and PLA and prints on standard desktop 3D Printers at PLA settings. It is very brittle in the filament state and seems like it would not be strong, but when you print and the melted PLA bonds and blends with the bronze it becomes very strong.

These filaments have all the advantages of PLA with interesting additions that allow the filament to change colour under different temperature, lighting or UV conditions. The heat change filament for example is a Blue when cold and changes to a White in your hands. This could potentially lead to a design that changes over design or with human intervention.

Perspex Polypropylene MDF Silicone Aluminum Styrofoam Alucabond

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FLEXIBLE FILAMENTS FLEXIBLE ABS

NINJAFLEX

MAKERBOT FLEXIBLE

This new version of Elastic-like or flexible filament is an experimental super elastic type filament available through 3D printing systems, the same manufacturers of our in house 3D printers (UP plus 2). This ABS has a rubber like effect, however is still plastic based and prints at normal ABS settings. It has positive reviews but is not as widely used as other flexible filaments.

Ninjaflex is a flexible filament made of rubber polymers and one of the most popular flexible filaments on the market. It prints much like ABS without the need for a heated bed. A key advantage of Ninjaflex is its capability of bonding with both PLA and ABS which opens the doors to composite 3D printed parts with both rigid and flexible elements. It is also readily accessible being stocked locally and relatively cheap.

MakerBot Flexible Filament’s has a low melting temperature of 60 degrees Celsius allows you to adjust your prints, changing the initial shape of the part by applying heat to it. The prints remain flexible at room temperature allowing stretching and bending. One major downside to this filament is its price. As a genuine makerbot product being an experimental filament prices from Bilby suggest prices around $240 per kg

TPU 92A-1 Thermoplastic Polyurethane is an experimental filament which introduced me to the world of flexible filaments. The material’s ability allows the creation of complex, light-weight structures with elastic properties. It is extremely flexible but highly abrasive and tear-resistant, and appears to have pretty excellent shape memory. Unfortunately this material is not ready for production or distribution to the general public, being reserved for use in professional manufacturing sectors.

CONSIDERATION Regardless of the flexible filament used, geometry plays a key role in the materials ability to flex stretch and bend. The more space and porosity of the geometry allows for a more sponge like squishy effect. Hollow shell geometries seem to work best in this regard. A denser fill and tightly packed geometry does exactly the opposite making the material still able to bend but not squeezed. Further experiments will be conducted over the coming weeks to explore the ramifications of these findings further.

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MACHINE RESEARCH IN HOUSE FABRICATION

OTHER FABRICATION OPTIONS

3D PRINTED METALS CONCRETE ETC

For reasons predominantly regarding accessibility and convenience. I will be making use of machinery readily available in the university.

Given the opportunity and access to other means of fabrication I would have liked to explore other fabrication methods. These other fabrication process would’ve extended the capabilities of my project and produced a different outcome.

While I tried to extend the capabilities of the in house printers by using other filaments such as PLA and flexible rubbers, I would have liked to explore printers that are capable of printing alternate materials such as metals, concrete and wood composites. These printers are also generally substantially larger than the printers we have in house, allowing the creation of larger parts.

The machines available to us through the FABLAB are: Card cutters Laser Cutters 3 AXIS CNC router 3D printers (UP Plus 2, Makerbot, Form1 and ZCorp) A large amount of focus on my project will be the use of 3D printers, which are readily available in the workshop. 3D printing is extremely powerful as it allows for rapid prototyping which is a great way to become intimate with the process of digital design and making. By experimenting with these technologies and extending their capabilities through flexible materials I hope to create a unique and interesting piece of furniture.

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This page outlines some of the fabrication methods I would have liked to explore:

ROBOTS

5 AXIS CNC ROUTERS

INJECTION MOULDING

Manufacturing robots have been in existence for many years in the automotive industry, but their applications into architecture and industrial design are still in their infancy. The university has invested into 4 robots to expand the FABLAB capabilities, though these wont be available for use until after the conclusion of this subject. While I have missed out on my chance to use it on this design project I look forward to exploring the potentials of this powerful fabrication method in the future.

One major problem with our in house CNC is that it is limited to cutting in 3 axis. Not all geometries are possible as the tool bit cannot access all areas particularly areas that lie beneath an overhang and require undercutting. 5 and 7 AXIS routers remove this limitation and allow the part to pivot and rotate. This allows the creation of virtually any geometry.

Injection moulding can produce similar results to that of 3D printing. While it is initially more rescourse intesnsive to set up moulds this system can produce inticate parts which are mass produced much faster than 3D printing. By injecting plasics and elastic materials these parts can be rigid or flexible. Injection moulding is the technique LEGO blocks are manufactured.

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