by Kip Hanson
Understanding the ROI of additive manufacturing
Shop owners lay awake nights thinking about spending $500,000 on a multi-tasking machine. Business managers develop complex spreadsheets and presentations for the board, evaluating the merits of a new powder coating line, or flexible manufacturing system. Difficult as these decisions are, they’re at least familiar ones, dealing with well-understood equipment. Not so with those contemplating investment in additive manufacturing, a.k.a. 3D printing.
Despite its now decades-long track record, additive manufacturing (AM) technology continues to evolve at a rapid pace, and for most in the manufacturing world it remains uncharted territory. The question then becomes how to convince shareholders—or the person staring back at you in the mirror—whether it’s wise to spend hundreds of thousands—perhaps a million dollars or more—on a process the inherent opposite of what we in manufacturing have been doing all our lives.
There’s no clear cut answer. AM is an umbrella term covering a broad landscape of materials, build speeds, part functionality, and cost. Some AM processes are good for little more than proof of concept models, while others are capable of making end-use parts for aircraft, automobiles, and the human body. All of them are slow compared to subtractive manufacturing, and nowhere near as accurate. And while AM offers literally hundreds of engineering grade materials, each technology is limited to its own process-specific materials, small subsets of what’s available to traditional machining and fabricating processes.
Despite these limitations, most experts agree that AM is here to stay, and will only increase in importance as designers learn to take advantage of its exciting potential. Lightweighting, part count reduction, complex shapes and part features difficult or downright impossible to achieve through subtractive machining methods—AM offers all this and more. These benefits, however, are generally realized only on new products, where a clean slate “what can we do with AM” design approach is used. Without this mentality, additive ROI can be difficult to achieve.
Robin Weston, Staffordshire, UK marketing manager for metrology and additive manufacturing provider Renishaw plc, says this is the challenge faced by AM adopters. “The technology is quite application specific, and some products are far better suited to AM than others.”
Renishaw offers 3D metal printing equipment, what Weston calls laser powder bed fusion. This is a generic term that goes around brand-specific acronyms to describe a process that melts individual particles of metal powder, fusing them together one layer at a time into dense, homogeneous parts made of 17-4, aluminum, cobalt chrome, and others. When first marketed, says Weston, these technologies promised complete design freedom, allowing designers to make just about anything they wanted. And while those claims have proven at least partially true, they unfortunately came with some baggage.
“The baggage is the support structures needed to build the parts, as well as the challenges of residual stress in the workpiece, particularly for very bulky parts,” says Weston. “What people have learned over the last 10 years of using these technologies is that the most successful applications are the ones where organizations are prepared to change product designs to suit the process. By being willing to do so, they’re also able to unlock the benefits additive can bring to many manufacturing organizations.”
This is a key consideration for any business considering an investment in additive. For deep-pocketed aerospace and medical companies, investment in the research and development needed to make AM play nice with product designs is a normal part of doing business. For job shops and small manufacturers with tighter budgets and little control over part geometry, Weston says to tread carefully. “You can end up in the situation where your customer will say, ‘what’s it going to cost to build one of these components?’ So you quote it on the basis of material volume, and how quickly you can lay it down. But because there are overhangs, hidden features, bulky cross sections, and a host of other additive gotchas, you’re going to find it quite challenging to make that part without first redesigning it for AM.”
Counting the hours
So what can one expect for ROI? Andy Snow, vice president of EOS North America Inc., an industrial 3D printing equipment manufacturer with North American headquarters in Novi, MI, offering direct metal laser sintering (DMLS) and polymer-based powder bed fusion systems, says the answer depends on how you’re using the machine and the types of geometry that you’re making with it.
“Generally speaking, if you’re using it for production of larger parts, there’s a higher value associated with that use and you could undoubtedly recoup investment inside of eighteen months and sometimes in as little as twelve,” Snow says. “Companies using machines for production purposes also typically get about 5,000 hours a year out of their machines, which also increases ability to recoup at a faster rate. If a company is using the machines for prototyping purposes, they typically receive a return on their investment of about 24 months after purchase, because those companies average only 3,000 hours a year.”
Ben Arnold, regional sales manager for another Michigan additive equipment provider, SLM Solutions North America Inc., says the manufacturing companies that offer AM-centric engineering solutions to their customers stand the greatest chance of success, and therefore the quickest ROI. This might mean looking at different ways to consolidate parts to reduce assembly costs, utilizing organic shapes to solve strength concerns, or honeycomb-like structures to reduce weight. “Rather than simply making whatever’s on the drawing or CAD file, you have to understand AM’s capabilities and encourage customers to make design changes to accommodate them, assisting them as necessary. These are the companies enjoying healthy returns and growth of their additive equipment investment.”
There’s more to AM cost than the equipment, warns Arnold. Gases, powders, lasers, electricity, build plates—these are just a few of the ongoing costs that must be considered in an ROI calculation. Chief among them is education. “You cannot just buy a machine. You also have to invest in the resources and the learning curve to become a teacher, so that you can lead customers into this world and show them how to design parts for AM.”
The situation is similar to that faced by early investors in EDM, or five axis machining centres, Arnold says. “People come to you for your expertise in a given area, more so than the equipment. It’s those companies that solve the needs of a specific industry that achieve sustainable ROI, because they’re most able to expand their customer base and develop additional opportunities.”
Arnold points to the valve industry as an example, where hydraulic manifolds and fluid control bodies with intricate internal galleries are the norm. As with the conformal cooling channels AM makes possible in plastic injection moulds, AM has the potential to blow away subtractive machining, which relies on costly drilling and then plugging of holes to create a labyrinth of hidden channels. Additive manufacturing, on the other hand, can build those channels
along with the rest of the part, regardless of their complexity. This provides more efficient flow paths, and channels that conform to the internal part geometry, providing better cooling and fluid dynamics.
AM is also an effective way to build near-net shapes, similar to castings, where only a small amount of post machining is required to be usable. “AM is like the next level beyond casting in terms of what is possible for geometry, and is another example where AM helps position manufacturers to succeed, Arnold. says. “Success with any technology is all about adding value. Additive is no different.” SMT