## 3 Methodology and Guidelines
### Potential Analysis
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt}} \hline \hline
**Driver** & **Guidelines to Help the Designer to Decide a Score** \\ \hline (D1) Does the use of AM lead to potential cost savings considering the entire life cycle? & AM is generally more expensive than a forming or machining technique due to long cycle times and high energy consumption. However, such a gap may reduce if considering the entire product lifecycle. It is the case of complex shapes optimized for highly efficient fluid-dynamic performances, devices such as blowers, diffusers, etc. Indeed, in some applications, AM allows us to reduce the mass, which is beneficial for product operating costs. For example, airplane mass reduction leads to fuel saving. \\ \hline (D2) Can assembly, logistic or procurement cost be reduced? & Forming technologies allow the realization of complex shapes but require investments for tooling that are recovered only if many parts are produced. Conversely, AM does not require fixed costs (apart from the printer itself) and it allows us to consolidate parts in less components of more complex components. A reduced number of parts is beneficial in terms of logistics, assembly times and supply chain management. \\ \hline (D3) Can the product benefit from a reduced time-to-market? & AM can be set up rapidly since it is based on a digital toolchain. Even if the realization time is high and some post processing activities can be required (support removal, post treatments, additional machining, surface coatings,... ), the whole process can be generally accomplished in few days, which is competitive with processes which require the elaboration of CNC toolpaths or the design and manufacturing of tooling and several sequential separated machines. Thus, the overall time-to-market could be significantly reduced. \\ \hline (D4) Is the production batch size limited? & As any other technology requiring limited fixed costs but longer manufacturing cost for each part, AM is more suited to small batch quantities. \\ \hline (D5) Is the post processing phase limited? & AM aims to produce near net shape parts. However, depending on the specific technology, post processing to consolidate the material, annealing residual stresses or improving surface quality may be required. The quantity of such activities can strongly reduce the competitiveness of additive solutions. \\ \hline (D6) Can material waste be reduced? & Nowadays, many materials are available to be processed with AM, some of them being expensive advanced metals. The advantage of adding material only where it is needed, conceiving complex organic shapes, and the possibility of recovering unused powders can lead to a reduction in material waste and improved sustainability. \\ \hline (D7) Would the product benefit from a mass reduction? & Mass reduction is one of the major strengths of AM parts, which has strongly pushed its diffusion. \\ \hline (D8) It is beneficial to increase the complexity of the part? & In some applications, such as fluid dynamics, biomedical applications (e.g., increase the osteointegration of the complexity of the shapes. \\ \hline (D9) It is feasible to consolidate parts? & Considerable advantages in terms of cost are gained if the number of parts can be reduced. AM can leverage the consolidation of parts if assembly and functional constraints are respected, also benefiting from grading material properties which can be conferred thanks to inner cavities or lattice structures. \\ \hline (D10) Is customization required? & The limited investment costs of AM pave the way to the paradigm of Mass Customization. Specific parts could be produced according to specific customer requirements, controlling the increase in production costs. \\ \hline (D11) Would the product benefit from areas with differentiated material properties? & One of the features of AM refers to the capability of calibrating the properties of the material along the part, recurring to modulation of micro-structures up to vary the distribution and parameters of lattice cells. For example, material properties can be varied accordingly to applied force, leading to uniform stress level and deflection behaviour that cannot be obtained with uniform material properties. If combining regions with different materials, the compatibility and weakness at the interfaces must be carefully assessed [12]. \\ \hline (D12) Would the product benefit from varied density along the volume? & The volumetric mass of a product can be modulated according to specific design objectives, thanks to lattice structures, inner voids or honeycomb structures. \\ \hline (D13) Is a volumetric lattice or a superficial texture required? & Superficial or volumetric structures can be obtained, enhancing weight reduction, or increasing osteointegration as well as grip. \\ \hline (D14) Is it advantageous to add functionalities in the parts? & The extended design freedom of AM allows multiple functionalities to be incorporated in a part, such as the possibility of integrating electric circuits. \\ \hline \hline \end{tabular}
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