More and more companies are examining the potential this approach offers for economical, short-run production of parts and products
By Terry Wohlers
Wohlers Associate Inc.
Fort Collins, CO
Web site: wohlersassociates.com
Additive manufacturing (AM) is a process of joining materials to make objects from 3-D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies. This wide range of technologies, which includes the sintering and deposition of materials, is increasingly being used for the manufacture of parts that go into products. This was not the case a few years ago, so what has changed?
A spirit of determination among users and producers has led to advances in AM machines, materials, and applications, propelling this technology to new heights. Aerospace, medical, dental, automotive, and consumer product companies are taking AM to places it has never been. The technology is now being seen as a solution for low-volume, high-value, and highly complex parts and products.
Unlike most established methods of manufacturing, AM offers a relatively new and cost-effective way to manufacture some types of parts and products quickly and relatively inexpensively. It’s now feasible to design some products in a day or two, and begin to manufacture them the following day. Small products have been completely designed, manufactured, and delivered within one week. While this may not be possible with larger, sophisticated products, it shows that when the need for tooling is eliminated, products can be produced very quickly.
New types of designs become possible with AM. Many design ideas never become products because companies and investors do not know whether they will sell. Alternatively, these unproven designs are too complex or expensive to produce. With AM, it’s possible to manufacture highly complex shapes and geometric features that could not be manufactured any other way. If a design can be modeled in 3-D on a computer, it can be manufactured with AM—with few exceptions. This capability, coupled with the elimination of tooling, makes it relatively easy for companies and individuals to create small quantities of a new product to see whether demand for it develops.
Fashion may be considered an unlikely industry to embrace advanced manufacturing technology, especially to the extent that it has. Shoes, clothing, and accessories made by AM have been featured at large fashion shows. For example, five pairs of shoes, manufactured in polyamide by laser sintering (LS), were worn by models at the Stockholm Fashion Show. Also, high heel shoes made by LS were a part of the Freedom of Creation (FOC) Future of Fashion exhibition at the Amsterdam World Fashion Center.
The use of AM to produce parts for aircraft and automobiles may be a more obvious and certainly a more demanding application for the technology. An aerospace company named Aerotonomy (Atlanta, GA) used NyTek 1100 carbon-filled LS material from Solid Concepts to manufacture the majority of the parts that make up the wings for an unmanned aerial vehicle (UAV). The LS process and NyTek material allowed Aerotonomy to produce the wings using far fewer parts than with conventional manufacturing. This reduction in component count can occur because the parts of a design are not restricted to the geometric limitations of molds and dies, which means two, three, even 10 parts manufactured the "old way" can be consolidated into a single part design.
The automotive industry, along with aerospace, was among the first to embrace AM technology for prototyping in the late 1980s and early 1990s. Now, automobiles made in relatively small volumes are including AM parts that would otherwise require tooling. For example, many of the interior and exterior parts on the Abruzzi car (from Panoz Auto Development, Hoschton, GA), were made by AM. Initially, 50 LS parts were made for a photo shoot of the car. The parts were good enough for the final product, and were used for the entire production of 81 cars. Nine of the parts were used in the instrument panel and several in the center console and armrests. These parts were covered with leather or another material.
Fused deposition modeling (FDM) is also being used for end-use part production. Mydea Technologies, a service provider in Orlando, FL, used one of its Dimension machines from Stratasys Inc. (Eden Prairie, MN) to produce 7000 parts for a supplier to BMW. The small parts were permanently assembled in an audio/visual device that went into a BMW car. The use of the relatively inexpensive Dimension machine to manufacture these parts was interesting because of the misconception among some that part manufacturing requires high-end and expensive equipment.
FDM is also being used for making tools, such as jigs, fixtures, and drill and alignment guides. The parts that make up these tools are often machined from aluminum, which can be expensive and time consuming. They are typically custom-designed and made in very low quantities, which makes them even more costly to produce. With AM, they are often manufactured in a fraction of the price and time.
An example is Wair Products (Bloomington, MN), a manufacturer of custom valves for a variety of fluids. The company designed a fixture that clamps to a liquid oxygen economizer valve and automatically sets the valve pressure. After the pressure is set, the fixture tests the pressure of the valve assembly. The valve regulates oxygen flow from portable oxygen tanks to humans. The usual process is to machine aluminum parts to produce the fixture, a method that was going to require the machining of eight parts and 3–4 weeks to complete. The company chose instead to produce a polycarbonate fixture using FDM. The result was a lighter, cleaner, and more compact design, coupled with significant time and cost savings.
Additive manufacturing is also having an impact on the production of metal parts for end-use applications—something that has developed in recent years. Two of the most popular metals used for AM are the titanium alloy Ti-6Al-4V and cobalt-chrome. The aerospace, medical, and dental industries are among the first to adopt this technology for production applications.
Manufacturers of airliners use metal brackets to connect cabin structures, such as kitchens, lavatories, and galleys, to the primary structure of the plane. Depending on the size of the aircraft, a single plane can require a thousand or more of these brackets. A German consortium consisting of Laser Zentrum Nord (LZN) GmbH, the Institute of Laser and System Technologies (iLAS) of Hamburg University of Technology, and Airbus Operations GmbH has redesigned a cabin bracket for additive manufacturing.
The consortium found that it could reduce the weight of a bracket by 50–80% using additive manufacturing. Brackets have been produced at LZN in Ti-6Al-4V on the EOSINT M 270 machine from EOS (Krailling, Germany), a SLM 250 HL machine from SLM Solutions (Lubeck, Germany), and an M2 machine from Concept Laser GmbH (Lichtenfels, Germany). Eliminating 100 kg (220 lbs) is said to save an airline $2.5 million annually in fuel costs for short haul flights.
Aerosud is a 650-person aerospace company in Pretoria, South Africa that produces assemblies for Airbus and Boeing. The company has investigated the capabilities and limitations of additive manufacturing for metal parts, and hopes to use it extensively in the future. Candidate parts are the many brackets, fittings, and other pieces located on the back side of a galley in airliners. Also, the company produces relatively large aluminum parts for aircraft wings by CNC machining, and hopes to replace this process with AM. One incentive to using AM is to reduce scrap, which is an estimated 95% for one part when machining it from a billet of aluminum.
The dental industry began to embrace metal AM in recent years. Already, more than an estimated 6000 dental copings are manufactured every day using direct metal laser sintering (DMLS) from EOS. A coping is the main structure of a crown or bridge, and is usually coated with porcelain to match the color of the patient’s teeth. An experienced dental technician is capable of producing about 8–10 crowns in a single workday. DMLS makes it possible to manufacture up to about 400 copings in cobalt-chrome in 20 hr. This time includes little human intervention, although a trained technician must prepare the data before the build begins. Also, the copings must be removed from the build plate, finished by hand, and coated and polished.
The orthopedic industry is also excited about what AM has to offer for the production of implants. In mid-February 2010, implant manufacturers in the US were given the "green light" by the US Food and Drug Administration (FDA) to manufacture certain products using electron beam melting (EBM) from Arcam (Molndal, Sweden). This permission is something that US manufacturers and others have been anticipating for some time. In 2007, orthopedic implant manufacturers in Europe received the first CE-certification—more or less Europe’s version of FDA certification. These manufacturers have produced and implanted more than 10,000 implants using EBM technology, with Ti-6Al-4V being the alloy of choice.
Where can AM go in the future? Companies in the aerospace, medical, and dental industries are investing heavily in additive manufacturing technologies. Many are doing their best to understand when it makes sense to consider AM, and when it does not. These industries are highly regulated, so the mainstream use of AM for the production of parts is not coming easily. Even so, the use of AM for end-use part production continues to grow in all of these industries.
Meanwhile, AM machines and kits for the do-it-yourself (DIY) market have become available, and are creating a lot of enthusiasm and chatter on the Internet. Today, it’s possible to purchase a kit for under $1000 and fully assembled machines for less than $3000. The quality of their output is not as good as one can get from more-expensive machines, but it’s improving.
For those who don’t want to purchase and operate an AM machine at any price, companies such as Shapeways (Eindhoven, The Netherlands), i.materialise (Leuven, Belgium), Sculpteo (Vanves, France), and Ponoko (Wellington, New Zealand) are providing easy access to products made by additive manufacturing on the Internet. Also, amateur and professional designers can submit their designs to these sites for production by AM.
All of the activity and passion surrounding AM, from the DIY enthusiasts to the most sophisticated aerospace and medical applications, are feeding on one another. The growing wave of interest is producing opportunists and entrepreneurs who can see how AM technology can be used to create new businesses and business models. Already, a number have created startup companies and some are doing very well. No longer does it require a great investment and risk to develop a product idea and manufacture it. Now, using AM, almost anyone located almost anywhere—even in a college dormitory or spare room in a home—can become a manufacturer. ME
This article was first published in the April 2011 edition of Manufacturing Engineering magazine. Click here for PDF.