In today's consumer-driven society, buyers are demanding ever faster order fulfillment and increasing levels of product personalization. In this environment, manufacturing companies often are hard-pressed to identify and adopt business processes and technologies that provide a truly competitive edge. But there is one approach that seems to offer the perfect solution: a concept known in North America as direct digital manufacturing (DDM) and in Europe and Asia as rapid manufacturing (RM).
Rapid manufacturing (the term we will use in this article) involves the economic manufacture of lowvolume products on demand at multiple locations near the point of consumption. Until recently, the ability to manufacture low-volume and even personalized products on demand had been limited almost exclusively to the two-dimensional printing sector, where it is used to create business cards, marketing literature, company reports, and the like as well as personalized consumer products such as coffee cups and tee-shirts. However, new developments in three-dimensional (3-D) printing technologies and a process known as additive layer manufacturing (ALM) have made RM feasible for some industrial manufacturing sectors, including automotive, aerospace, and medical supplies.
Making products to order when and as needed, exactly where they are needed, could help companies reduce their transportation and logistics costs, facilitate a reduction in their environmental footprints, and appeal to consumers who support ethical purchasing. Moreover, rapid manufacturing is considered by many to be one of the most important potential influences on the future of manufacturing.
It is for these reasons that RM has been cited as the catalyst for a potential "industrial revolution for the digital age."1 But the implications of a move toward RM extend far beyond the manufacturing process itself. This agile production strategy enables a truly distributed supply chain, where manufacturing can take place concurrently at multiple locations that are located close to the consumer. This new structure could eliminate many stages of the traditional supply chain, affecting lead times, inventory management, and transaction and logistics costs.
Layer by layer, in 3-D
Rapid manufacturing depends on the use of additive layer manufacturing processes. ALM technologies have been widely used for more than 20 years to manufacture prototypes and casting patterns. However, recent advances in ALM and materials now allow the rapid manufacture of end-use parts for a variety of production applications in materials such as metals, polymers, and ceramics.
ALM consists of three basic steps. First, a 3-D computer representation is fed into a specially designed layer manufacturing machine. The initial 3-D data can come from a variety of sources, including computer- assisted design (CAD) packages or from contact and noncontact scanning systems. Other commonly used data sources include computer tomography (CT) and magnetic-resonance imaging (MRI) medical scans and more recently, computer games programs.
Next, the image is digitally sliced up into hundreds of two-dimensional layers, each representing a profile through the part to be manufactured. Finally, the layers are rebuilt inside the ALM machine one at a time, from the bottom up, until the part is complete.
Different ALM processes build and consolidate layers in different ways. Some systems use thermal energy from laser or electron beams, which is directed via optics to melt or sinter (form a coherent mass without melting) metal or plastic powder together. Other systems use ink-jet-type printing heads to accurately spray binder or solvent onto powdered ceramic or polymer. Regardless of which techniques and materials are used, the net result is the same: a solid, tangible representation of the original computer data, with no mold tooling, no machining, no jigs to hold the work in place, no fixtures, and no manual intervention required.
Unique business benefits
Rapid manufacturing processes offer businesses a number of unique benefits in a wide range of areas, including operational costs and efficiencies, product innovation, and environmental impact. The following list briefly introduces some of the most important benefits:
1. Without the constraints of tooling, jigs, and fixtures, RM gives manufacturers the ability to cost-effectively produce batch sizes of one. Companies can reduce or eliminate their capital investment in such fixed assets, and there is no associated amortization of tooling costs. Products can be brought to market more quickly, at far lower cost and with far less risk. This is particularly appealing to small, fast-moving companies and the innovator community. New products can be launched with limited financial investment, as RM machine capacity can be purchased as and when needed from service providers or bureaus. Alternatively, many companies choose to invest in in-house ALM capacity. However, this can be a bold decision; machine tools range in price from US $25,000 for simple, low-production polymeric systems, up to US $750,000 or more for high-throughput metal and ceramic processing technologies.
2. RM enables the production of highly complex geometries that would be impossible to make as single items using traditional manufacturing processes. As a result, manufacturers can consolidate formerly separate parts, thus reducing manufacturing, assembly, and inspection costs. Additionally, RM enables the manufacture of topologically optimized components, where complex structures with optimized strength-toweight distribution can be manufactured at no extra cost. This allows a manufacturer to reduce both the amount of raw material needed in production and the subsequent weight of the production part. This is a particularly important benefit to the automotive and aerospace industries.
3. Because RM uses layered manufacturing, many of the traditional "design for manufacture" principles no longer need apply. For instance, it may no longer be necessary to design split lines into products to enable removal from tooling, or to maintain constant material- wall thicknesses in order to eliminate shrinkage in casting, to give just two examples.
4. Additive-layer processes allow more "functionality" to be added to parts as they are being built. Examples include designed porosity in medical implants to promote cell ingress, variable mechanical properties within a single part, and the addition of "intelligent" devices such as fiber optics, strain gauges, and shape-memory alloys between layers.
5. With no need for production tooling, RM makes it possible to manufacture the same part at multiple locations that are very close to customers. This can mitigate single-source supply chain risk while eliminating many stages of traditional supply chains, including transportation of finished goods, thereby reducing lead times, inventory, and logistics costs.
6. Because parts are made using additive manufacturing (as opposed to the typical subtractive machining or formative molding processes), RM processes usually generate little, if any, waste material.
Almost all current users of rapid manufacturing around the world have exploited one or more of these business benefits. Hence, it can be surmised that RM has the potential to benefit companies where:
It could be argued that this list represents a significant proportion of manufacturers within developed Western economies, where to maintain a competitive advantage against low-cost overseas competition companies must design and produce increasingly complex products—in ever-decreasing volumes—which are either highly personalized for small consumer groups or unique to an individual customer. That is why more and more companies in a broad range of industrial sectors are expected to adopt rapid manufacturing as an economical tool for meeting customers' expectations and requirements. (For some example of industries where RM is making headway, see the sidebar titled "Who is using rapid manufacturing?")
RM and the environment
The business benefits cited earlier referenced a subject that affects every company's supply chain: the need to curb the impact of manufacturing and distribution on the environment. The global importance of this issue calls for a more detailed look at how RM can be an effective tool for mitigating environmental damage.
RM limits the amount of energy used in manufacturing. Rapid manufacturing has the potential to replace processes such as casting or molding, in which significant amounts of energy are wasted in changing materials from solid to liquid form, or in other processes that require material pre-heating and cooling cycles. Contrast that with some ALM processes, which use only the energy needed to consolidate the materials required for one part at a time.
Rapid manufacturing reduces material waste and scrap. Although polymeric RM processes do produce waste powder or support structures, many of the newer, direct metal powder-bed and powder-feed systems can achieve material efficiency of up to 97 percent. This capability has the potential to significantly reduce the amount of scrap produced during manufacture. Compare this, for example, to traditional aerospace machining, where it is not uncommon for only one kilo out of every 20 kilos of material purchased to actually end up in the machined parts. The remaining 19 kilos of material becomes scrap, which then requires costly and energy-inefficient reprocessing.
RM eliminates the need for some types of potentially harmful chemicals. Machining for many materials requires the addition of cutting fluids, which use water resources and produce hazardous industrial waste—a problem that is largely absent in RM environments.
RM promotes more efficient use of raw materials. Globalization and rising living standards in nations like India and China will continue to stretch the global supply of commodities like copper, titanium, and steel. With reserves of some materials (copper, for instance) being depleted, material-efficient production technologies like RM will become more important.
RM enables environmentally friendly product design. Traditional manufacturing processes place many constraints on product design. RM's flexibility allows manufacturers to optimize design for lean production, which by its nature eliminates waste. Moreover, RM's ability to construct complex geometries means that many previously separate parts can be consolidated into a single object. Additionally, the topologically optimized designs that RM is capable of realizing could increase a product's functionality, reducing the amount of energy, fuel, or natural resources required for its operation. However, to date topological optimization has only been applied to simple, static RM consumer products such as tables and chairs, where the effects of material optimization are being used purely for aesthetics, rather than for functional weight saving. However, once validated in industrial applications, this will be a driving factor in RM adoption; it is already under investigation by companies such as Boeing and Airbus.
Rapid manufacturing reduces fuel consumption and vehicle emissions. Because RM typically uses the absolute minimum amount of material, the process can significantly reduce the weight of parts and components. Lighter-weight automotive or aerospace parts will decrease the overall weight of the aircraft or vehicle, thus reducing the equipment's fuel burden and carbon footprint throughout its lifecycle. Furthermore, because manufacture can be undertaken near the ultimate consumer, RM can in many cases reduce or even eliminate the need for transportation, storage, and protective packaging of finished goods, reducing fuel consumption and greenhouse gas emissions.
Implications for the future
Ongoing research in rapid manufacturing will continue to produce technical advances that could lead to significant improvements in production costs, product design, and the environment. However, there are some areas (briefly discussed earlier in this article) where RM could have especially far-reaching consequences and therefore merit further examination.
RM has great potential for facilitating change by freeing innovators from traditional production and financial constraints. Rapid manufacturing's "tool-less" distributed structure allows companies with little investment capital to develop and bring to market complex new products and associated services. It also has enabled a new model in some areas of the consumer goods marketplace, realigning the traditional manufacturing- distribution-retail model into a new model in which retail activity takes place before manufacture. This provides working capital to a business with almost no up-front, fixed tooling and production costs.
Indeed, although rapid manufacturing is still very much an emergent technology, it has the potential to stimulate the creation of entirely new businesses, markets, and sectors, along with their associated supply chains. A good example is the manufacture of invisible dental braces. U.S.-based Invisalign Inc. uses RM to manufacture forming tools over which disposable, transparent dental braces are individually formed in sets for each patient. Invisalign has become a global phenomenon in the dental-supply sector, with the company growing from nothing to $206 million in sales in less than five years.
Yet rapid manufacturing can also be a disruptive technology. Consider the example of polymeric RM, which has already been established as a cost-effective alternative to injection molding for low-volume parts. Manufacturers that use this technique no longer need to purchase equipment and services from molding companies, tool and die makers, cutting-tool supply companies, and other traditional suppliers. Similarly, as metallic RM technology develops, it will progressively replace machined components—and the need to do business with machining companies. Importantly, such developments will affect not just the immediate suppliers of materials and services but also the extensive supply chains associated with those branches of manufacturing.
Societal and cultural issues that one might think have little to do with manufacturing and production will almost certainly encourage the adoption of RM in the future. RM is already being used to address such issues, including an aging population, the need for affordable health care, and demographic shifts. Societal changes, coupled with increased technological capabilities in the home, will help drive the use of RM to manufacture unique and customized consumer products. Over the next 20 years, we will see a migration of manufacturing, initially from centralized factories to more distributed factories, and then over time to truly localized, even home-based, manufacturing solutions.
All of the developments discussed here could potentially have enormous consequences for traditional supply chains. First, we will see far more products being made at multiple locations, rather than at single sites. This change will be driven by both the ability to balance supply and demand between ALM machines, and the economic, environmental, and social benefits of locating production nearer to the consumer or original equipment manufacturer.
This business model is already being exploited by a division of the author's own company, which enables consumers to design toys from video games, order them online, and have them manufactured locally by the most appropriate supplier, thus reducing cost, lead time, and environmental impact. Similar business models are also being used to make home goods such as lampshades and gifts. It is only a matter of time before this methodology is adopted by automotive and aerospace companies. The net effect is likely to be a larger number of small manufacturing facilities, possibly clustered around either niche supply chains or advanced materials.
Based on current research, we expect to see the development of ALM technologies that can build complete systems, including electronic, optical, and mechanical components. This will further compress supply chains, eliminating multistage manufacturing and drastically reducing the need for transportation, warehousing, and logistics activities.
The most profound and far-reaching impact on the supply chain, however, will result from affordable, home-based ALM systems, the first of which will debut mid-way through 2009. When integrated with the Internet, home-based ALM could bypass the conventional product supply chain altogether, allowing users to download digital data (for a price) for home-based manufacture. A home-based manufacturer will need to stock small amounts of special materials at their sites and will likely be served by parcel and express carriers rather than by large transportation providers.
Could RM become to tangible product manufacturing what the download has been to the music industry—an opportunity for early adopters but a threat to traditionalists? Just as iTunes disrupted the music industry and changed how music is purchased and delivered, the emergence of home manufacturing could collapse supply chains as RM transforms how certain types of products are purchased, produced, and delivered.
1. Neil Hopkinson, Richard Hague, Philip Dickens (editors), Rapid Manufacturing: An Industrial Revolution for the Digital Age (Hoboken, New Jersey: John Wiley & Sons Inc., 2006)
With rapid manufacturing offering so many benefits right now and holding so much promise for the future, it is not surprising that there has been a sharp increase in the number of companies using RM in a broad range of industrial sectors. In transportation equipment and technologies, for example, companies such as Boeing, Airbus, BAE Systems, Renault, and Honda are using RM for a variety of applications. These include polymeric parts such as air ducting; heating, ventilation, and air conditioning components; dashboard substrates; and electrical housings. RM is also being used to make a limited number of parts from metal materials, including drive shafts, gearbox components, and suspension and braking systems.
Health care represents probably the most diversified market for rapid manufacturing products. RM is being used commercially to manufacture bone-replacement material for reconstructive surgeries and for creating customized prosthetics. RM also makes possible disposable surgical cutting guides, which are personalized to the individual patient. Other medical applications include the manufacture of housings and components for low-volume medical devices such as specialized scanning machines, blood centrifuges, and monitoring systems.
Dentistry is one of the best-known applications for RM; doctors are using the technology to manufacture customized dental caps, bridges, and crowns. By far the most common medical application at present is the production of personalized in-the-ear hearing aids, which are manufactured to fit exactly into each patient's ear.
Rapid manufacturing even has a place in the creative arts, where it is used to manufacture products from designs that simply cannot be made with traditional processes. This has been especially successful for manufacturing unique items, including lamp shades, jewelry, and architectural products. One company even allows customers to design 3-D picture frames and giftware online; the products are then created using RM and shipped by mail directly to the customers' doors. Another company is using 3-D printing to manufacture toys and action figures from video game images.