3D Printing Metal: Elements of Promise?
Gearing Up for 3D Printing Metal
This article reviews the 3D printing metal market and looks at current trends and recent applications before examining the barriers to further progress and what business opportunities might be available in the future.
The polymer 3D printing market, particularly the desktop segment, experienced a rapid influx of new companies during 2015. Such an oversupply of providers will be addressed by a shakeout of weaker players and a wave of acquisition and consolidation as the market matures. In contrast the market for 3D printing with metals remains underdeveloped and an attractive prospect for enterprises that can overcome the associated hurdles.
These hurdles include the higher barriers to entry for metal 3D printer manufacturers. When core patents for SLS expired in 2014, some commentators anticipated a rush of new entrants comparative to that seen after FDM patent expiry in 2009. Predictably this influx did not occur due to two major differences from FDM, these can be summarized as technical barriers and a fear of litigation. 3D printing metal is a substantially more complex process than working with polymers and requires printers that have a greater degree of sophistication. To attain this technical level, components for production control and monitoring are required in excess of those for working with filament. Furthermore, while the original components of SLS patented by Carl Deckard in the 1980s entered into the public domain the substantial improvements and processes built upon this foundation remain subject to intellectual property laws. These technical barriers and the role played by established market participants, who have demonstrated no lack of willingness to defend their IP, has ensured that the available options to print metal remain sparse in comparison to the polymer segment.
It is also important to consider the economies of scale for users working with 3D metal printing. The price / volume curve for feedstock, often in the form of metal powders, requires enterprise users to have a significant volume of work for raw material costs to become cost effective. Furthermore, higher marginal costs are due in part to the energy required to melt metals. For example, titanium has a melting point of 1668ºC, aluminum 660 ºC, Inconel 1390–1425 ºC and stainless steel 1510ºC. Purchase and operation of lasers with sufficient power to work effectively with metals is often costly. Although several desktop metal printers and methods such as producing casts via FDM do exist, there is a wide variation in quality in comparison to industrial metal printing machines.
Rob Weston of Renishaw believes that barriers to consumer adoption can be addressed by opening solution centers, or locations where high-grade metal printers are available to use on site under short-term rental contracts. The Wohler’s report notes that while the professional metal printing sector has experienced percentage growth rates substantially in excess of the polymer segment in recent years, the number of printers installed at business locations is remarkably low. A case in point here is the fact that the University of Birmingham in the United Kingdom recently became the first university in the world to install a multi-laser metal 3D printer.
Not Just Lasers
Laser based methods are not the only techniques for working with additive manufacturing and metals. A prototype method for the depositing of cooper via electrolysis was demonstrated by Ionpath at during the Santa Clara Inside 3D Printing conference in October 2015. While the Ultrasonic Additive Manufacturing (UAM) process from Fabrisonic uses sound waves to produce 3D metal objects. The novel UAM method uses a rotating ultrasonic transducer to deliver kinetic energy to a vibrating welding horn. This horn applies force to bond metal materials in a solid state. In Germany, members of the PT Scientists group are experimenting with microwaves as an alternative to lasers for working with hybrid materials. Specifically, the PT Scientists group is working on methods to build structures on the moon. The research conducted by the group proposes using in-situ materials rather than transporting chemical binders from Earth. The rational for using lunar regolith is that a 30-ton rocket on Earth results in a final payload of only 100 kg on the moon. The team aim to launch their experiment on 7thDecember 2017, the 45th anniversary of the Apollo 17 expedition. Once on the moon the experimental rover will deploy a magnetron based microwave device that can process lunar regolith. Lunar regolith has elements of iron and by subjecting the regolith to microwave heating a liquid phase can be created and subsequently shaped. The eventual goal is to create a device that will allow structures to be built layer by layer, however an initial goal will be to create simple roads and melt the surface of craters to form satellite dishes.
Lunar regolith is an uncommon material to use in 3D printing and off-world samples are in limited supply. The simulated versions available on earth do not accurately mirror the properties of the actual rare material and scientists hope that the Chang’e Chinese space program voyages may result in the collection of regolith that can be used for further experiments. More common materials in metal 3D printing include aluminium oxide, stainless steel and titanium and less commonly bronze, silver and gold. Titanium alloys represent almost one-third of the total market, a market analysts predict will grow at a rate of 32% during the next 10 years. Such forecast
s are supported by the announcement by GE of a $3.5 billion investment to enable 100,000 metal fuel nozzles to be printed and also Arcam’s plans to manufacture 50,000 orthopaedic implants. Titanium’s characteristic strength to weight ratio make it an important material in aerospace, an industry at the forefront of much metal 3D printing technology. The traditional Kroll process for extracting titanium from ore is lengthy and must be conducted at high temperatures. During 2015, SRI International announced an alternative method of extraction that uses plasma arcs and involves fewer steps. The SRI process also produces titanium in powder, rather than ingot, form. It hoped that once the process is fully scaled then cheaper titanium powder will enable 3D metal printing to become cost effective in a wider range of industries and become more widely used.
Current uses and applications of metal 3D printing are widely reported by the aerospace and automotive industries in both the prototyping and more recently the production of final components. Repair of vehicle and machinery components using 3D printing has been demonstrated by several groups, including the Chinese military. In the field of health care Chinese doctors have used 3D printing to create personalized surgical implants, specifically a construction worker from Beijing who lost half his skull in a work accident received a 3D printed titanium replacement.
While the benefits of 3D printing (less waste, cheaper complexity, new materials and structures etc.) are clear there are still technical barriers to wider adoption. These include the speed at which objects can be produced and for high production volumes 3D printing cannot compete with traditional manufacturing. However, machine manufacturers are addressing the question of speed. For example, a Toshiba machine to be launched in 2017 claims a production rate of 110 cubic cm per hour whereas typical build speeds in the current market range from as low as 5 and up to 70 cubic cm per hour. The German company, SLM Solutions, have also improved the production speed of their machines by adding additional 400W lasers and there is high demand for their range of industrial machines. Other approaches to the speed challenge include the direction taken by Israeli company Xjet who are working with inkjet technology and liquid metal inks. The company has announced they will launch a printer capable of creating stainless steel objects from liquid metal during 2016 and they anticipate liquid aluminium and titanium products will be forthcoming.
The Future of Work?
Other aspects of the future of 3D printing metals include the benefits that stem from collaboration between specialists in a range of fields. As in the polymer space, metal 3D printing benefits when multidisciplinary collaboration occurs, Silos of isolated knowledge represent an antiquated model for 3D printing and while specialization is necessary, practitioners must be able to work well with other experts. Consumer education is also necessary to communicate what additive manufacturing is (and is not) suited for. This criteria must include an appraisal of the purpose of the object, its size and volume, the size of the production run, and whether rare or difficult to work with materials are utilized. 3D printing with metals, and other materials, may require alternate business models and the organization of production resources. University of Southern California professor, Behrokh Koshnevis, presents the concept of telecommuting as a possible future organizational model for manufacturers. Unlike traditional factories, the workers are separated from machinery and may even live on the other side of the world. Remote access to machines allows workers to perform their duties without having to set foot in the factory. This has numerous benefits including improved health and safety and increased workforce participation by underrepresented groups. Koshnevis argues there is an opportunity to lower business overheads as telecommuting factories can be established in regions where real estate and energy costs are low.
Telecommuting can be seen as related to the larger mega-trend, Industry 4.0, specifically when discussing the opportunities for decentralizing enterprises. Here, the combination of multiple emerging technologies such as the Internet of Industrial Things, Big Data and automation is likely to involve the use of 3D printing metals to bring benefits to society and 2016 may be the year the technology reaches a wider audience.
This article was originally written for 3D Printing World.
