The Digital Transformation of Logistics. Группа авторов

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СКАЧАТЬ resins) Cost‐effective way of producing custom thermoplastic parts/prototypes; low‐cost consumer machines and materials availableHigh production speedWide range of thermoplastic materials available Good, isotropic mechanical propertiesNo support required (designs with complex geometries can be easily produced)Excellent manufacturing capabilities for small to medium batch production Disadvantages Brittle (not suitable for functional prototypes)Mechanical properties/visual appearance degrades with long exposure to UV lightSupport structures always required; post‐processing needed to remove visual marks Low dimensional accuracy and resolution (not suitable for parts with intricate details)Likely to have visible layer lines, requires post‐processing for smooth finishAnisotropic (directionally dependent)Low accuracy, low level of details Grainy surface finish, internal porosity (may require post‐processing, if smooth surface or water tightness needed)Cannot print large flat surfaces and small holes accurately Applications Functional prototyping, patterns, molds, and tooling, dental applications, jewelry prototyping and casting, and model making Low‐cost rapid prototyping, basic proof‐of‐concept models Functional prototyping, short‐run, bridge, or custom manufacturing

Table 4.2 Comparison of main materials used in AM.

      Source: Based on Ngo et al. (2018). © John Wiley & Sons.

	Polymers and composites	Metals and alloys	Ceramics
Advantages	Fast prototypingCost‐effectiveComplex structuresMass customization	Multifunctional optimizationMass customizationReduced material wasteFewer assembly componentsPossibility to repair damaged or worn metal parts	Controlling porosity of latticesPrinting complex structures and scaffolds for human body organsReduced fabrication timeA better control on composition and microstructure
Disadvantages	Weak mechanical propertiesLimited selection of polymers and reinforcementsAnisotropic mechanical properties (especially in fiber‐reinforced composites)	Limited selection of alloysDimensional inaccuracy and poor surface finishPost‐processing may be required (machining, heat treatment, or chemical etching)	Limited selection of 3D‐printable ceramicsDimensional inaccuracy and poor surface finishPost‐processing (e.g. sintering) may be required
Applications	AerospaceAutomotiveSportsMedicalArchitectureToysBiomedical	AerospaceAutomotiveMilitaryBiomedical	BiomedicalAerospaceAutomotiveChemical industries

      Given this wide range of technologies and materials, AM will highly likely impact production processes, which will be discussed in the next sections.

Application Scenarios

AM will surely affect supply chains and the whole economy, although there are opposing views to what extent. For instance, Richard D'Aveni, professor of strategy at Dartmouth College's Tuck School of Business, refers to it as “3‐D Printing Revolution,” explaining that “Industrial 3‐D printing is at a tipping point, about to go mainstream in a big way” (d'Aveni 2015). Others also refer to it as “gold rush” that will dramatically change “supply chains, firm strategies, competition, and industrial geographies” (Sasson and Johnson 2016). Contrary to these optimists, some experts are more skeptical, considering AM only as complementary to conventional manufacturing that will be applied in very specific scenarios (Verboeket and Krikke 2019). AM is particularly suitable for products that have complex shapes. In conventional manufacturing, the more complicated the shape of an object, the higher the manufacturing costs. However, in AM, fabricating an intricate, complex shape does not require more time or cost than a simple block (Lipson and Kurman 2013). This also allows for the manufacturing of “generative design parts.” While in traditional design, humans are drafting the concrete end product, generative design relies on computational algorithms, which generate designs based on certain input parameters such as purpose, size, strength, weight, or cost constraints. By simulating physics, sometimes inspired by biological systems, thousands of design options are virtually explored until the best, optimal design solution is found for a particular problem (Xponentialworks 2020). For example, the industrial control and automation company Festo developed a gripping arm that, modeled based on the complex kinematics of a bird's beak and designed considering the forces acting on the component, possesses a unique force‐to‐weight ratio (Calignano et al. 2017). AM additionally offers a chance for parts that are characterized by a high risk of obsolescence and high shortage costs, such as spare parts (Holmström and Partanen 2014). John T. Lee, responsible for managing print store ABC Imaging's 3D modeling and rapid prototyping services, explained that he sees a “future where people and architects and engineers – rather than sending an order to a warehouse to get a spare part – will download a CAD file and have it printed in their neighborhood print shop.” He also added that “right now, we're not that far away from that model already. All day long, our bicycle couriers come in and out of here to deliver printed parts to our customers” (Lipson and Kurman 2013). Products in short supply can also be quickly and flexibly manufactured, thanks to AM (Pérès and Noyes 2006). For instance, at the height of the COVID‐19 pandemic in the United States, additive manufactures produced urgently needed and difficult to obtain protective equipment material such as face shields. The chief product officer of the AM company Formlabs stated “I can't even tell you how many hospitals, and various other health institutions and health‐care providers and governments, have asked us to help out with the situation” (Page 2020). AM is also suitable to produce production tools such fixtures, jigs, gauges, molds, or dies. Tools produced via AM offer a new approach to improve productivity through better cycle times, machine performance, and tool changeovers (Ford and Despeisse 2016; Materialise 2020). In addition, without geometric constraints, design efforts can be concentrated on part functionality and assembly. Therefore, AM can be used to produce assembly parts that are optimized for low part count and fabrication in an assembled state. This is especially valid as conventional manufacturing constraints such as material sizes or coordinate systems and symmetric axis for machining do not have to be considered, so that parts can be created with doors and attached interlocking hinges at the same time (Atzeni and Salmi 2012). AM is also predestined to manufacture single unit items. As AM removes the overhead costs needed for retraining operators and retooling machines, units with the lot size one, such as individual gears, discontinued and antique parts, custom‐fit dental protheses, hearing aids, or even components for the Mars rover can be produced at affordable costs (Lipson and Kurman 2013). This goes along with the possibility to manufacture customized consumer products. Traditionally, executives must balance being as customer driven as possible, including inventing new programs and procedures to meet every customer's request, while not adding too many unnecessary cost and complexity to operations (Gilmore et al. 1997). As companies can overcome this dilemma with AM, fully customized consumer products such as bicycle frames (UK bicycle frame manufacturer Reynolds), razors (shaving and razor brand Gillette), or shoes (sportswear manufacturer Adidas) emerged (Vialva 2019).

      Given these application scenarios and the considerable research undertaken in the field, the AM market is growing, and new technology trends are emerging. This will be described in the following section.

Market СКАЧАТЬ