Expanding the Scope of Additive Manufacturing

Uploaded 16 Mar @ 15:33pm

In addition to the latest tablet PCs, smartphones, virtual reality headsets and other digital devices that delighted both children and adults this Christmas, it is possible that one or two of these lucky individuals may have also received a 3D printer. With the expiry of the initial patents, more affordable pricing has only recently seen the entry of these remarkable machines into the general consumer market. However, the technology upon which they depend was developed by the Japanese industrial researcher, Dr Hideo Kodama, back in 1980.
Building on Kodama’s work with UV polymerisation of photosensitive resins, over the next four years, the concept was successfully applied in a process termed stereolithography by a US engineer named Charles W Hull, who later founded the 3D Systems Corporation. Realising that the technique could be applied to any material capable of solidification or a change of state, he saw stereolithography as the basis of a brand new approach to manufacturing in general. Like Kodama, however, his first use of this technology was as a rapid procedure for building model prototypes for test purposes.
Most modern 3D printers now employ one of three main techniques that emerged during the ‘90s. These form the basis of the growing field commonly termed additive manufacturing. Today, this versatile technology is either already in use, or currently undergoing development for use, in applications in outer space, on the ground, on the ocean floor and even within the recesses of the human body. In effect, additive manufacturing appears set to transform the way we make things forever.

Trading subtraction for Addition
Since early humans first began to make simple tools and weapons from the natural resources around them, the manufacturing process has been primarily a subtractive one. Fragments of flint were fashioned into spearheads or axes simply by chipping away the excess flint to create the shapes required. In more modern times, blocks of timber or metal have traditionally been turned on a lathe or milled in order to remove unwanted portions of the blocks and reveal the desired shape within, perhaps an ornate chair leg or a precision made engine part.
Even though the discarded materials can sometimes be reclaimed and put to alternative uses, the subtractive process is inherently wasteful and waste, in turn, can add unnecessarily to the cost of manufacture. By contrast, additive manufacturing reverses the traditional approach. Rather than starting with excess raw material and removing portions to create the finished product, the additive approach begins with no more than a plan, a set of digital instructions and the machinery to apply them. In practice, the instructions direct the actions of a 3D printing device, to create a finished product by depositing successive layers of an appropriate raw material until it is complete.
This transition was made possible by the merging of two technologies, each of which continues to be used independently. Traditionally architects and engineers recorded their ideas and assembly instructions in the form of hand-drawn blueprints until the emergence of computer-aided drafting software (CAD) made it possible to create plan and elevation views in a fraction of the time. Soon after came the means to render these 3D images and, from these, to construct digital models with which to test a product’s performance without the need to manufacture it.
The logical extension of this technology was to reference these digital constructs in order to actually manufacture the successfully tested product. To make this possible, pioneers like Kodama and Hull adapted existing 2D printer technology to operate in three dimensions, and to employ materials such as thermoplastics, metals, concrete and even living cells, in place of toner.
While additive manufacturing procedures eliminate the waste incurred by their subtractive counterparts, one of the problems that needed to be overcome is the slower rate of operation. Its initial use for so-called Rapid Prototyping was a bit of a misnomer given that doubling the size of an object actually cubed the time required to print it. Consequently, until this problem could be overcome, 3D printing technology was restricted to the fabrication of smaller items such as toys and machine parts.
Consequently, much of the more recent research into this technology has focused on speeding and upscaling the operation of these devices. In turn, the developer’s efforts have been rewarded with some outstanding achievements, both for large and small scale applications, and in some remarkably diverse fields.

Bigger is better
Need a house in a hurry? The solution may be to print it. Increasingly, China has been positioning itself at the cutting edge of applied technology and its engineers have been quick to find a way in which to apply 3D printing to address one of the planet’s greatest needs – affordable housing. The Chinese construction company Winsun created world headlines when, in 2014, it employed four gigantic 3D printers to construct 10 houses in a single day. The company used recycled building materials to form a concrete aggregate that served as the ‘ink’ for their 10 m tall and 6.6 m wide printers.
These machines, however, could only produce the structural components and some manual intervention was needed to complete the assembly. Nevertheless, their success triggered a virtual explosion in the development of rapid construction methods. Following Winsun’s pioneering achievement the process has since been refined to print complete structures. Currently, engineers in Dubai have been mooting the construction of the world’s first 3D printed skyscraper while the Saudi government is negotiating a 5-year contract with Winsun to print a massive 1.5 million new homes.

Small, smaller, smallest
While some developers have focussed on upscaling this technology others have been applying it to perform progressively smaller tasks. The efforts of the latter have been rewarded with some incredible results. 2013 saw the first successful printing of DNA molecules from its component bases, guanine, adenine, thymine and cytosine, by the US biotech company Cambrian Genomics. This prompted the Wyss Institute at Harvard to take this achievement one step further. From synthetic DNA, researchers fashioned a bacteriophage and used it to infect a culture of E coli.
Known as bioprinting, the ability to reproduce whole human organs was first realised in 1999 when a patient was given a replacement bladder that had been printed from his own cells. Just 3 years later, the first working, 3D printed kidney was announced. Applied with equal success to the manufacture of perfectly tailored prosthetic limbs, bioprinting displays the potential to change the way doctors heal their patients forever.
Some of the planet’s endangered lifeforms could also benefit from this type of application. Marine scientists are already investigating its possible use to repair ailing coral reefs and perhaps even to construct new ones.

The Economic Implications of Additive Manufacturing
Not only has additive manufacturing contributed to lower operational costs that have benefited both the producers and the consumers; the cost of migrating to this technology has itself been falling steadily over the past few years. While purchasing a fairly basic 3D printer might have cost a business around £20,000 just three years ago, today there are a number of equally capable units on offer for less than £500.
This, of course, will be widely seen as good news by those manufacturers who are contemplating the move to an additive process. It is, however, a trend that also carries a more far-reaching implication. Those in the automotive and aerospace sectors seem set to gain the potential to fabricate even the biggest and most intricate of their components and, at some stage, perhaps even fully assembled cars and planes, using this rapidly developing technology. That said, it appears equally likely to change the future for the smaller operator also. Already, many of the world’s entrepreneurs have begun to applaud this new paradigm as heralding the long-awaited democratisation of manufacturing.

New opportunities
for the entrepreneur
While the kings of industry continue to produce everything from microwave ovens and washing machines to prosthetic limbs and rocket engines, the 3D printer also opens up a niche opportunity for everyone from cash-strapped students and single mums to pensioners. Anyone with an idea, who possesses the knowledge and the software with which to express that idea as a digital image need only purchase an affordable 3D printer to transform the concept into a profitable business.
Ideal for the production of small, one-off, personalised items to be marketed online, these could include anything from kid’s toys and novelty key fobs to stylised sunglasses and crash helmets. It is a flexible option that allows products to be based either upon the producer’s or the customer’s design. Alternatively, one might simply fabricate small components for other businesses that lack this technology. In practice, the designer’s imagination may be the only limitation on the potential of this exciting small business opportunity.
Understandably perhaps, it is possible that some established industries might perceive this proliferation of additive manufacturing as a threat. In practice, the more enlightened stance is to accept that it amounts to no more than a re-definition of traditional roles.

What might
the Future hold
It may not yet match the capabilities of the voice-activated replicators aboard the fictional Star Ship Enterprise and be able to fabricate anything from a three-course meal plus a vintage wine to a new uniform. Nevertheless, despite what might yet prove to be only a temporary restriction, the potential uses for the 3D printer in a steadily expanding range of activities would appear to be virtually without limit.
Though not regarded as a manufacturer in the generally accepted sense, the biomedical sector may well be the one with the most to gain. The field holds some interesting possibilities, especially when one remembers that artificially fabricated DNA has already been used to produce a virus. This implies that the technique could be modified to construct other living organisms which, unlike viruses, could replicate without the need for a host.
Government organisations like NASA and private aerospace companies such as Space-X seem certain to leverage this technology increasingly in a bid to make the exploration of space more cost-effective. In addition to promising much cheaper rockets, it is a move that could herald a paradigm shift. It will grant engineers the freedom to print structures off-world using raw materials gathered from the lunar or Martian surfaces, or even mined in the asteroid belt rather than continuing to plunder the earth’s dwindling resources.
The near future promises more affordable printing of metal objects, major advances in the various tools that provide a substitute for the print heads in 2D models and a surge in the materials that now serve as the ink.
A $1.5 billion investment in additive manufacturing by General Electric Aviation has already earned it more than 300 patents for new powder metals. It is a trend that others are certain to emulate and one that will ensure an exciting future for those who embrace this innovative technology.

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