In recent years 3D printers have become financially accessible to small and medium sized business, thereby taking prototyping out of the heavy industry and into the office environment. It is now also possible to simultaneously deposit different types of materials.
While rapid prototyping dominates current uses, 3D printers offer tremendous potential for production applications as well.[1] The technology also finds use in the jewellery, footwear, industrial design, architecture, automotive, aerospace, dental and medical industries.
Technologies
Previous means of producing a prototype typically took person-hours, many tools, and skilled labor. For example, after a new street light luminaire was digitally designed, drawings were sent to skilled craftspeople where the design on paper was painstakingly followed and a three-dimensional prototype was produced in wood by utilizing an entire shop full of expensive wood working machinery and tools. This typically was not a speedy process and costs of the skilled labor were not cheap. Hence the need to develop a faster and cheaper process to produce prototypes. As an answer to this need, rapid prototyping was born.
One variation of 3D printing consists of an inkjet printing system. Layers of a fine powder (plaster, corn starch, or resins) are selectively bonded by "printing" an adhesive from the inkjet printhead in the shape of each cross-section as determined by a CAD file. This technology is the only one that allows for the printing of full colour prototypes. It is also recognized as the fastest method.
Alternately, these machines feed liquids, such as photopolymer, through an inkjet-type printhead to form each layer of the model. These Photopolymer Phase machines use an ultraviolet (UV) flood lamp mounted in the print head to cure each layer as it is deposited.
Fused deposition modeling (FDM), a technology also used in traditional rapid prototyping, uses a nozzle to deposit molten polymer onto a support structure, layer by layer.
Another approach is selective fusing of print media in a granular bed. In this variation, the unfused media serves to support overhangs and thin walls in the part being produced, reducing the need for auxiliary temporary supports for the workpiece. Typically a laser is used to sinter the media and form the solid. Examples of this are SLS (Selective Laser Sintering) and DMLS (Direct Metal Laser Sintering), using metals.
Finally, ultra-small features may be made by the 3D microfabrication technique of 2-photon photopolymerization. In this approach, the desired 3D object is traced out in a block of gel by a focused laser. The gel is cured to a solid only in the places where the laser was focused, due to the nonlinear nature of photoexcitation, and then the remaining gel is washed away. Feature sizes of under 100 nm are easily produced, as well as complex structures such as moving and interlocked parts.[2]
Each technology has its advantages and drawbacks, and consequently some companies offer a choice between powder and polymer as the material from which the object emerges.[3] Generally, the main considerations are speed, cost of the printed prototype, cost of the 3D printer, choice of materials, colour capabilities, etc.[4]
Unlike "traditional" additive systems such as stereolithography, 3D printing is optimized for speed, low cost, and ease-of-use, making it suitable for visualizing during the conceptual stages of engineering design when dimensional accuracy and mechanical strength of prototypes are less important. No toxic chemicals like those used in stereolithography are required, and minimal post printing finish work is needed; one need only brush off surrounding powder after the printing process. Bonded powder prints can be further strengthened by wax or thermoset polymer impregnation. FDM parts can be strengthened by wicking another metal into the part
Resolution
Resolution is given in layer thickness and X-Y resolution in dpi. Typical layer thickness is around 100 micrometres (0.1 mm), while X-Y resolution is comparable to that of laser printers. The particles (3D dots) are around 50 to 100 micrometres (0.05-0.1 mm) in diameter
Applications
An example of real object replication by means of 3D scanning and 3D printing: the gargoyle model on the left was digitally acquired by using a 3D scanner and the produced 3D data was processed using MeshLab. The resulting digital 3D model, shown on the laptop's screen, was used by a rapid prototyping machine to create a real resin replica of the original object. Standard applications include design visualization, prototyping/CAD, metal casting, architecture, education, geospatial, healthcare, entertainment/retail, etc. Other applications would include reconstructing fossils in paleontology, replicating ancient and priceless artifacts in archaeology, reconstructing bones and body parts in forensic pathology and reconstructing heavily damaged evidence acquired from crime scene investigations.
More recently, the use of 3D printing technology for artistic expression has been suggested.[5] Artists have been using 3d printers in various ways.[6]
3D printing technology is currently being studied by biotechnology firms and academia for possible use in tissue engineering applications where organs and body parts are built using inkjet techniques. Layers of living cells are deposited onto a gel medium and slowly built up to form three dimensional structures. Several terms have been used to refer to this field of research: Organ printing, bio-printing, and computer-aided tissue engineering among others.[7] 3D printing allows to manufacture a personalised hip replacement in one pass, with the ball permanently inside the socket, and even at current printing resolutions the unit will not require polishing.
The use of 3D scanning technologies allow the replication of real objects without the use of molding techniques, that in many cases can be more expensive, more difficult, or too invasive to be performed; particularly with precious or delicate cultural heritage artifacts.
Future applications may allow many of the familiar pieces of furniture in a contemporary home to be replaced by the combination of a 3D printer and a recycling unit. Clothing, crockery, cutlery and books can already all be printed on demand and recycled after use, meaning that wardrobes, washing machines, dishwashers, cupboards and bookshelves may eventually become redundant.
Prototyping technologies and their base materials
Selective laser sintering (SLS): Thermoplastics, metals, sand
Fused Deposition Modeling (FDM): Thermoplastics
Stereolithography (SL): Photopolymer
Lamination systems: Paper and plastic
Electron Beam Melting (EBM): Titanium alloys
3D Printing (3DP): Various materials
3D PRINTING: THE FUTURE FACTORY
I see textiles as an industry ripe for a new manufacturing model that is more adaptable, customizable, much cleaner, more socially conscious, and smaller-scaled. Yes, smaller-scaled.
The common wisdom is that the exodus of manufacturing and capital to China (and other industrializing countries), is the wave of the future. But I believe that the manufacturing model being implemented in many cases (massive factories, massive pollution, mass production) is a dead end, like the Neanderthals.
Mass production doesn't work anymore. It's an early industrial model that uses too many resources, and creates too much pollution, to produce goods that sit on warehouse shelves growing outdated, or getting shipped around for discount reselling (creating yet more pollution).
I'm convinced that the future of manufacturing, including textiles, is in collective design and 3D printing (aka rapid manufacturing, digital manufacturing). The following ideas and links are largely inspired by a fascinating TED talk by MoMa design curator, Paola Antonelli, on her 2008 MoMa exhibition "Design and the Elastic Mind." Watch it!
2D digital printing is already revolutionizing print manufacturing. 3D printing, which sounds like the stuff of Star Trek or The Jetsons, is already being used for product prototyping, and is beginning to be used for small-run production of real goods.
Designer Janne Kytännen, describes himself as a "Pioneer in Design for Digital Manufacturing." His company, Freedom of Creation (FOC), is already producing "laser sintered" textiles and hard products using 3D printers.
"Chain mail" textile produced by 3D digital printing. Designer: Janne Kytännen, FOC
Last month, Seed Magazine published an account of RepRap, the self-replicating rapid prototyper, which costs a couple hundred dollars to assemble, and uses open source software. Its creator, Adrian Bowyer of the University of Bath, says that the technology of RepRap will lead to the "decentralization of all industrial production."
Child's shoes, made with RepRap 3D printer, Adrian Bowyer, University of Bath, UK
Google's Open Source Programs Manager, Chris DiBona says, "Think of RepRap as a China on your desktop."
In the USA, Evan Malone, Ph.D., has developed another 3d Printer, called the Fabber. Malone has also made his software open source, and has consciously worked to make the purchase price of the printer as low as possible, to encourage as much user experimentation as possible. (The current price of a Fabber kit is about $2000.) A variety of materials can be used for fabrication (i.e. silicone, wax, plaster, epoxy, chocolate, etc). Listen to the podcast about the Fabber on Phorecast. You'll be blown away.
With 3D printing technology improving quickly, the availability of open source software, and non-proprietary materials, 3D printers for small-businesses are becoming a real, and immediate, possibility. If you think that's far-fetched, consider what happened to the personal computer in the span of a few decades:
Besides the "Ooooh, cool" factor of digitally printed 3D objects and textiles, this technology has incredible potential to actually improve products and reduce waste through collective design and mass customization.
Bruce Sterling compares the new model of "mass customization" with the old model of mass production. Mass customization is a production process where different entities, including the customer, are involved in the manufacture of the product. Dell, Inc., already uses this model successfully. The customer "custom-builds" the exact computer she wants using menu items on the website, and the final computer is assembled only after she places the order.
Some benefits of mass customization and collective design, are:
The customer gets exactly what he wants;
Natural, energy, and people resources are not wasted on unwanted products;
Transport pollution is minimized: product is shipped once - directly to the customer;
Overhead is lowered, as warehousing finished products is eliminated;
Products do not become outdated, because they are not made until they are purchased
Adding 3D printing technology to the equation:
Designs and products can be adapted on every level as new information and needs arise;
No need to re-tool machines for design changes -- all changes are made in programming;
Internet and PC technologies make global business possible even for small businesses;
Short-run production and "originals," are possible;
Natural resources are further preserved by eliminating pre-manufactured components.
I believe that it is only a matter of time before 3D printers are able to create a variety of tactile qualities, textures, weights, and colors, opening the way for beautiful design and a brand-new model of production that is adaptable, portable, and green. That is hope for the future.
Rapid Manufacturing In Rapid Manufacturing products are constructed layer by layer, without a mould. No material is removed, as happens in machining. The necessary data are taken directly from the design process. This has a number of advantages. A physical product follows quickly on the heels of the design and (test)products reach the market more quickly.This flexible method simplifies the manufacture of very complex products and makes it easier to combine more parts.
TNO's RM technologies and Demo Centre
Until now Rapid Prototyping has been used primarily in industry as a visualisation technology, for the rapid manufacture of an initial tangible product, a 'conversation piece', straight from CAD. But the series production of functional products has failed to materialise due to limitations in processes, materials and product finishing. In recent years huge advances have been made on all these fronts - thanks in part of TNO´s efforts. We are seeing a shift from Rapid Prototyping to Rapid Manufacturing (RM). The rapid series production of functional end-products is now possible. The advantages of this are evident: no tool costs, very short time to market, rapid implementation of any product changes, low stock costs, if any, and, of course, the lower cost price of the end-product.
Applications
Despite the many steps taken, RM is not yet suitable for all applications. Often, production speed, the production process and the type of material are limiting factors when it comes to applying this production method on a large scale. This has prompted TNO to work on basic technologies to enable the machines to produce more quickly, more accurately and using a broader range of materials, as well as in an expanding field of application. Not only must the materials be suitable for processing in the machines, they must ultimately also satisfy the product requirements imposed on the end-product.
The push is now on to turn rapid manufacturing into a technology that is mass market and low cost. Tom Shelley reports
Developments in rapid manufacturing technologies - and designing to take full advantage of these - are set to bring about a revolution in design and manufacturing.
Customisation will become the norm, rather than the exception, and more and more products will be made locally or even in the home over the next decade.
Price mark-ups of the first manufactured products to get to market are, in some cases, 10 to one, and market demand is now beginning to drive the technology. Rapid production of more and more consumer and medical products at lowering costs is gathering pace - and, in time, this may even embrace replacement human body parts.
These were the messages to emerge from the 'Manufacturing Reinvented' seminar at London's Royal College of Art, which made it clear that rapid manufacturing of consumer products is already upon us. Upmarket lighting and furniture, dental implants, braces and false teeth, jewellery, and customised ear plugs and hearing aids are already being produced by additive methods derived from computer scans and models, often at large cost mark-ups.
While most of the early adopters, according to Dr Phil Reeves, managing director of Econolyst, are based around people, this has not been exclusively so. There has also been the rapid manufacturing of aluminium heat sinks for use in a helicopter, for example, as Dr Chris Sutcliffe from the University of Liverpool, pointed out. And the technology also extends to the creation of certain parts used in motor sport and some top end cars as well.
"The biggest challenge to rapid manufacturing is the production of full scale, verified and useful manufactured parts over a wide range of applications," states Sutcliffe. "The majority of manufacturing machines are very expensive, very slow, very difficult to use, are maintained by their suppliers at high annual cost - and it probably won't be very long before your machine is obsolete. There are many process variables that are not yet fully understood and the metal powders are mostly hazardous to work with." According to Professor Richard Hague, the barriers to even wider adoption are a lack of repeatability by existing systems and the need to change the culture of organisations to accept new technology. "Improved design software is also required to maximise the design potential of products the systems are able to make," he says.
Hague is the head of the rapid manufacturing research group at the University of Loughborough. This is engaged in a project to develop tailored injury prevention and performance improvement for protective sports garments (Scuta). While it is fairly easy to scan in a human body shape and produce a rigid moulding to fit, there is a need to make it in the form of connected panels to give it flexibility, without compromising its protective properties. So body surfaces need to be meshed, but in a different way to that used for finite element modelling.
Mixing up the medicine
Meanwhile, the solution to the lack of cheap machines is to make your own, argued Dr Adrian Bowyer of the University of Bath. He has for some time been pushing forward a project called RepRap (www.reprap.org), in which the majority of parts for a design of a fused deposition modelling machine, called Darwin, are themselves made by FDM, so one machine can be used to make more machines.
"It still needs nuts and bolts, and electric motors," says Bowyer. "Things that have to be added in have to be widely available and very cheap." The motors cost £1.50 each and the Cartesian robot to support the write head requires M8 studding and a couple of sheets of MDF. It also uses microcontrollers connected on a token ring and programmed in 'C'. The development cost of the project was £20,000, plus the cost of supporting a PhD student, and the target cost of all raw materials, motors and chips is £250. The print head currently uses polycaprolactone, but that may soon change. "We want to switch to polylactic acid, which can be made by fermenting starch," he said - and showed an example of such a part produced by one of the machines in New Zealand.
Professor Julian Vincent, also from the University of Bath, pointed out that biologically derived materials can be very strong indeed - or have their mechanical properties tailored to end use. Biological polymers are based on either proteins - such as spider silk, which can be stronger than Kevlar and highly energy absorbing - or on polysaccharides, exemplified by chitin, which, he claims, "competes with carbon fibre".
Before industry can rapid-manufacture in spider silk, though, there are a few more things to learn. Nonetheless, the path to the future is clear. Take, for instance, Janne Kytannen's Netherlands-based business Freedom of Creation. Once, it was largely dependent on government support for what were mainly research projects. Now, it is strictly commercial, producing designer lighting, furniture, jewellery, handbags and packaging. In terms of time to market, Kytannen says he completes most of his design projects in a single day and, on one occasion, completed a design on his laptop while travelling in a taxi from New York's JFK Airport. After receiving the customer's approval, he had parts delivered to clients five days later. Products can even be manufactured inside their own packaging, he adds.
Additive rapid manufacturing is the first major challenger to the three traditional ways of making things that have been used since ancient times, says consultant Geoff Hollington. Those processes are 'subtractive' (carving material away, as in flint tool making and modern machining), 'moulding' (pottery, casting and plastic moulding) and 'forming' (bending, forging and stamping).
"Maybe we have to turn to a new kind of mechanical design," he says, citing the 'Octo arm', a pneumatically operated elephant trunk type grasping actuator, as being ideal to manufacture by rapid manufacturing.
At the seminar, Hollington spoke about "life without motors, shafts or gears" and offered a glimpse into the future: a pen with ink inside a fluid muscle type envelope, with the rest of the pen built up around it; and of modular loud speaker units, from which large systems could be built up, and a single speaker with acoustic spikes inside that could not be made by conventional manufacturing methods. He also identified the year 2000, when rapid prototyping started to be supplanted by the first rapid manufacturing, as "the year when we began to lose our bearings".
This was topped by Reeves and Sutcliffe - who foresee the printing of human cells to make new body parts. Sutcliffe regards the printing of biological materials as being potentially of much greater value than printing consumer products. It was generally agreed that, when the fundamental patents underlying most of the current rapid prototyping and manufacturing technologies ran out, a drastic cut in the cost of machines is likely.
As Geoff Hollington pointed out: "We are where the Industrial Revolution was in about 1800."
Pointers
* Rapid prototyping is presently being supplanted by additive rapid manufacturing
* The fastest growing, most profitable areas are currently in the production of products, both medical and consumer, that are matched to fit the various parts of the human body
* There is strong market pressure to improve the performance/price ratio of rapid manufacturing machinery. Within a few years, they could cost hundreds of pounds each, a vast reduction on today's prices
