Additive Manufacturing
this can take hours, even tens of hours, for large parts and large build volumes. And post-processing steps, including the removal of support material, stress relief, and finishing, can be quite labor intensive. Myth #2: Additive manufacturing is fast. AM systems build parts by depositing, fusing, curing, or laminating consecutive layers of material. These layers are typically 0.001 to 0.010" (0.025–0.254 mm) in thickness, so parts often require thou- sands of layers. Defining the perimeter and solidifying the area of each layer for large volumes can be quite time consuming. The period between layers also adds time. Processes that operate with a heated build chamber take time for preheating and cooling cycles. With all the required steps, some jobs take several days. Myth #3: AM is greener than conventional manufacturing. At one time, many hoped that one-off, distributed manufac- turing would result in more energy-efficient products. How- ever, the studies completed to date—mostly in Europe—do not necessarily support this theory. AM processes consume more electrical energy per unit mass of material produced compared to conventional processes. When combined with new design capabilities, less material, fewer parts in invento- ry, and the elimination of tooling, the picture improves. This is especially true when compared to waste-intensive pro- cesses, such as CNC machining. In the aerospace industry, the environmental benefits of AM-enabled weight reduction are clear, because weight reduction results in substantial fuel savings. We know now that assessing the environmental benefits of AM is a very complex exercise that requires an analysis of the entire life cycle of a product, from raw mate- rial processing to the product’s end of life. The industry will need to embark on thorough, cradle-to-grave assessments of AM’s energy efficiency.
AM systems build parts by depositing, fusing, curing, or laminating consecutive
layers of material. These layers are typically 0.001 to 0.010" in thickness, so parts often require thousands of layers.
Myth #4: AM systems can produce anything. The ad- age “if you can design it, you can build it” is generally true, as most AM processes are blind to the complexity of a part
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and can successfully build shapes that cannot be fabricated easily or at all using conventional methods of manufacturing. However, AM processes also have limitations. One is mini- mum wall thickness. Another is the requirement for supports and anchors on down-facing surfaces, which can be difficult or sometimes impossible to remove. Material that is trapped in internal channels can also be difficult or impossible to re- move, and the size of the internal channels impact the degree of difficulty in removing unwanted material.
Global athletic leader New Balance in March announced a significant advancement in the use of 3D printing to customize high performance products for athletes. At the New Balance Games in January 2013, Team New Balance athlete, Jack Bolas, became the first ever track athlete to compete in customized, 3D printed plates.
Myth #5: With AM, it’s just as efficient to build one part at a time as it is to build many. Depending on the process, pack- ing the build volume with parts makes a significant difference in the per-part build time, cost, and energy consumed. AM comes with economy of scale, especially with powder bed processes, where the entire build volume can be filled, and stacked, with many parts. A similar myth is that it’s just as efficient to make 50 custom parts as it is to make 50 copies of a single part. In reality, while build time and expense may be the same, the pre-build file preparation and post-build part finishing may be considerably more time-consuming when each part is unique. Myth #6: AM systems and materials are inexpensive. It’s true that some 3D printers for hobbyists and do-it-yourselfers are inexpensive. The least expensive 3D printer, the Maki- Box, lists for $200. The list price of Concept Laser’s X line 1000R metal AM system in Europe is €1.4 million. Generally, industrial AM systems are more expensive than CNC machin- ing centers. And materials are far more expensive. Plastic materials for AM can be 53 to 104 times more expensive than plastic materials for injection molding.
Photo courtesy New Balance
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