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The revolution will be printed: innovations in 3D printing turned many heads at K2013.

The problem with the K trade fair is that it is simply too big. The recent K 2013 saw thousands of exhibitors-from major plastics producers, such as Bayer MaterialScience and DuPont, to manufacturers of plastics processing machinery, plus consultants and publishers--fill 19 massive halls spread over the area of a university campus in Dusseldorf, Germany.

While this size and diversity ensures that the K fair is a preeminent event for the global plastics industry, it also makes it almost impossible to identify a central theme. Now, this isn't important for the vast majority of the thousands of visitors to the event, but it certainly is for a writer trying to make sense of the whole thing.

This year, however, help came from the organizers of K 2013, Messe DQsseldorf, who placed a major focus on 3D printing and the potential benefits it offers to the plastic industry. This included producing a special brochure detailing all those companies exhibiting at K 2013 that are involved in 3D printing.

In 3D printing, also known as additive manufacturing, a computer-generated design is built up layer-by-layer. This can be done by depositing successive layers of a plastic or metal powder that are then heated with a laser to solidify them, known as laser sintering, or by depositing layers of molten plastic that harden on cooling.

It's certainly true that 3D printing has taken off over the past few years. The ability to buy build-it-yourself 3D printers for under a thousand dollars or Euros, together with the proliferation of open-source designs for everything from ornaments to chemical reaction vessels, has encouraged many people to start printing much of what they need.

Custom Parts

Meanwhile, companies are being enticed by the ability to print components and parts that are lighter than those produced by conventional manufacturing processes, as the component can be printed just as required rather than having its design constrained by the manufacturing process. For example, the European defense and aerospace company EADS is now using 3D printing to produce some titanium components in its aircraft; these printed components are up to 60% lighter than the conventionally produced versions. As an added advantage, printing a component also generates much less waste.

Furthermore, 3D printing is bringing about the rise of custom manufacturing, in which products can easily and cheaply be customized and tailored for specific customers or applications by simply altering the computer-generated design. One of the earliest applications of 3D printing was the production of hearing aids designed to fit the specific shape of a patient's ear. Now it's also being used to produce football footwear made for the shape of individual feet.

For the plastic industry, 3D printing offers a cheap and easy way to produce plastic prototypes, with the advantage that these prototypes can readily be tweaked and modified. On top of this, however, it also offers the possibility of producing molds for conventional plastic processing and manufacturing technologies, such as injection molding. As with the prototypes, the design of these molds can be easily tweaked and modified. All of these applications were demonstrated at K 2103, but there were also signs that 3D printing could soon be moving beyond the production of prototypes and molds into proper manufacturing, albeit at a small scale.

More Realistic Materials

The growing level of interest in 3D printing and the possibilities it offers was amply demonstrated by the fact that some of the companies on the list put out by Messe Dusseldorf were only tenuously related to 3D printing. Other companies on the list, such as Stratasys and EOS, are recognized pioneers in 3D printing; both have been developing 3D printers and materials for over 20 years. But it is only recently that the potential applications have really exploded, mainly driven by growth in the variety of materials, including plastics, that can be used.

For example, Stratasys now supplies nearly 150 different thermoplastics and photopolymers (which are solidified by UV light) for its 3D printers. In November 2013, it announced the launch of a new acrylonitrile butadiene styrene (ABS) material called Digital ABS2 for its PolyJet 3D printers. This new material is both rigid and durable, allowing it to be used for printing thin-walled models.

At K 2013, however, the company focused on the many benefits that 3D printing can offer to plastics manufacturers. It reported on its work with Seuffer, a German supplier of parts for household appliances and commercial vehicles, which uses Stratasys's Objet30 Pro printer to produce prototype parts, plus molds for injection molding and hot melt processes.

"Working with the automotive industry, sample parts need to be tested in the environment of moving mechanical parts as well as in high-temperature environments," explains Andreas Buchholz, head of research and development at Seuffer. "With Stratasys 3D printing, we can design first drafts of the injection mold within a few days and 3D print them in less than 24 hours for part evaluation. Traditionally, it would take eight weeks to manufacture the tool [mold] in metal using the conventional CNC (computer numerical control) process. And while the conventional tool costs us about 40,000 [euro], the 3D printed tool is less than 1000 [euro], a savings of 97%."

Complex Designs

Likewise, EOS highlighted the benefits of its 3D printers for producers of plastic products. It reported on its work with Kuhn-Stoff (a German prototype designer and developer), which was asked by Wittmann Robot Systeme (a German subsidiary of the Wittmann Group that manufactures automated system) to redesign a mechanical gripper. This gripper utilizes a pneumatic mechanism to pick up, transport, and set down machine parts on a production line.

The existing version of the gripper was constructed from 21 different components made from aluminium, rubber, and plastic, and it was expensive to produce. Wittmann Robot Systeme wanted a simpler, cheaper, and lighter alternative. Using EOS's FORMIGA P 100 3D printer, Kuhn-Stoff developed a new version consisting of just two different plastic components: a square central body and four identical gripper pads placed at each corner of the central body.

This new version is 86% lighter than the previous version, weighing just 220 g, and takes a quarter of the time and costs half as much to produce. Nevertheless, it's said to be just as strong and robust as the previous version, able to move the required loads for more than 5 million operating cycles.

"In a single process step, we were able to create a functionally integrated part that exceeded all of the requirements of the client," says Hannes Kuhn, CEO of Kuhn-Stoff. "In short: additive manufacturing is now an everyday reality, but the results are still extraordinary."

"The Next Level"

Nevertheless, 3D printing remains limited by the fact that it can only work with a subset of available plastics. In order to work in a 3D printer, plastic materials need to possess certain properties, such as melting to a consistency that allows them to be deposited through an inkier-like nozzle and dry quickly. Up to now, this has often required developing plastic materials specially designed for 3D printing, which tends to be quite expensive. Some plastic materials, such as the quick-drying silicone polymer used as bathroom sealant, do naturally possess the right mix of properties.

What would really push 3D printing to the next level, though, is being able to use it with the kinds of major plastic materials used in conventional processing technologies, such as injection molding. As well as further expanding the possible applications for 3D printing, this would also open up the possibility of using 3D printing for the manufacture of commercial products, rather than just prototypes and molds. Rather handily, this is exactly what was announced at K 2013.

One of the more surprising names on the brochure put out by Messe Dusseldorf was Arburg, a major German manufacturer of injection molding machines not known for its involvement in 3D printing. However, at K 2013, Arburg announced the launch of a new 3D printing system, known as "freeformer," which is able to work with exactly the same plastic materials as those used in conventional injection molding machines.

In developing the freeformer, Arburg tapped all of its experience with injection molding. Indeed, Arburg claims that the freeformer essentially works in the same way as its injection molding machines, using a heated plasticizing cylinder to melt plastic granules. This plastic melt is then fed through a patented nozzle that utilizes high-frequency piezo technology for fast opening and closing. The nozzle deposits the plastic melt onto a surface as droplets under pressure, building up the resultant object droplet-by-droplet. Arburg claims that the plastic products created by this printing process, which it terms "Plastic Freeforming," possess 70-80% of the strength of conventionally produced injection-molded plastic parts.

Where the freeformer differs from most other 3D printers is that rather than building up the product by moving the nozzle over a stable surface, it keeps the nozzle stable and moves the surface beneath it. By being able to move the surface in many different directions, and also potentially to tilt it, this approach allows the freeformer to build up solid objects without employing the supports that are required by other 3D printers. In addition, the freeformer is available with either one or two nozzles, with the two-nozzle version able to produce objects consisting of two different plastic materials, such as rigid and flexible materials.

"With the launch of the freeformer and Arburg Plastic Freeforming, we are taking a revolutionary step in the context of the history of the company and of the industry as a whole," said Herbert Kraibuhler, Arburg managing director for technology and engineering. "We look forward to the future, certain in the knowledge that the freeformer will tap into as yet completely new areas of application."

Styrenic 3D Apps

Other major plastics companies, such as Styrolution, are now beginning to explore the potential of 3D printing, with the aim also of pushing it into new applications. Styrolution was formed in 2011 from the combination of the styrenics businesses of BASF and INEOS, and is now the world's largest producer of styrene monomer and polystyrene.

Recognizing that styrene and 3D printing have a lot to offer each other, Styrolution recently started a research collaboration with Hans-Werner Schmidt, head of macromolecular chemistry at the University of Bayreuth in Germany. "[Schmidt] is a world-renowned material scientist," says Norbert Niessner, Styrolution director of global R&D and intellectual property. "Together with him, we have started a collaboration on 3D printing, because we are both convinced that only by understanding the basic structure-property relationships of polymers and their interaction with 3D printing can we offer the best solutions to our customers."

The big advantage of utilizing styrenic plastics with 3D printing is that styrene can easily be chemically modified and combined with other polymers, producing a wide range of different styrenic plastics with many different physical properties. Furthermore, the surface of styrenic polymers are readily customizable for adding characteristics such as antimicrobial and self-cleaning properties.

"We believe that 3D printing is a revolution and that it will proliferate in the future," says Niessner. "1 personally believe it will revolutionize the way industry manufactures prototypes, and we want to be the future partner for our customers to provide the right material."

As K 2013 amply demonstrated, 3D printing already offers a lot to plastics producers, but it could soon offer a whole lot more.
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Comment:The revolution will be printed: innovations in 3D printing turned many heads at K2013.
Author:Evans, Jon
Publication:Plastics Engineering
Geographic Code:4EUGE
Date:Nov 1, 2013
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