Functionally Graded Additive Manufacturing: Bridging the Gap between Design and Material Extrusion

Abstract

Nowadays, the use of 3D printing is becoming a key process for on-demand and customized manufacturing. One of the most flexible 3D printing techniques is fused deposition modeling (FDM), where the combination of multiple materials was recently introduced. A quantum leap in part design is possible by integrating local variations between materials that allow for expanded functionality to be built into a single part. Therefore, the process of co-extrusion and material mixing is becoming more and more popular. The process of management and design of the engineered part are still complicated, and there are no commercially available tools that follow the process from design to production of these highly engineered products. This paper proposes a methodology to fill this gap and allow any designer to be able to produce multi-material parts by editing a G-code (computer numerical control programming language) with engineered gradients for FDM technology. More specifically, the proposed approach is based on the modification of the G-code according to a volumetric model describing the local combination of two or more materials. This original aspect allows for a wide extension of the current software capabilities. To explain and test the method, a simple test case was investigated, in which two components of an earphone are consolidated and developed gradually by combining polylactic acid and thermoplastic polyurethane. The results show the effectiveness of the proposed approach within the limits of the material coextrusion additive manufacturing process.

Multi-Material Additive Manufacturing: Creating IN718-AISI 316L Bimetallic Parts by 3D Printing, Debinding, and Sintering

“…After solution heat treatment, particles are decorated by Cr-oxide, while, inside the particles, Cr-nitrides in the form of rods were detected, due to the nitrogen oversaturation followed by precipitation during quenching. These new insights should be integrated into the frameworks of design for AM and multi-material AM [35,[55][56][57], including the multi-material models that are essential tools for the part of geometry and material distribution design. As mentioned, the PDS of metals is an eco-friendly AM process due to the low energy consumption and low waste material [18].…”

“…More broadly, environmental implications of metal AM, oriented to functionally graded materials in a circular design perspective, were previously discussed [58][59][60] and could be integrated in a comprehensive design methodology that considers the PDS process, the functional requirements, and the sustainable development. These new insights should be integrated into the frameworks of design for AM and multi-material AM [35,[55][56][57], including the multi-material models that are essential tools for the part of geometry and material distribution design. As mentioned, the PDS of metals is an eco-friendly AM process due to the low energy consumption and low waste material [18].…”

“…Multi-material PDS opens up numerous possibilities for the production of new functionally graded materials by AM technologies [33,34] characterized by a particular local combination of properties depending on the alloys coupled and their configuration in the coextrusion process. In this scenario, components could be designed in a way that specific mechanical, chemical, thermal, and physical properties can locally change according to the application [35]. Due to the diffusion during the sintering process of metals, multi-material PDS results in a more complex materials interaction compared to polymers coextrusion [36].…”

Experimental Comparison of Fastener Implementation Approaches in Fused Deposition Modeling

“…In FDM printing, by leaving gaps in the interior of the parts, the part can be made lighter without affecting the external form of the part, and these gaps can also be used for different purposes as they can react differently to sound waves and RF signals [18,19]. These spaces also allow us to insert functional objects into the part during printing [20]. These functional objects may be a magnet, sensor, or strength-enhancing support structure, or it may be possible to place fasteners such as bolts and nuts.…”

Numerical Modeling of Mechanical Behavior of Functionally Graded Polylactic Acid–Acrylonitrile Benzidine Styrene Produced via Fused Deposition Modeling: Experimental Observations

“…The second method is the liquid state method and involves the external addition of reinforcement particles to the melted material [ 12 , 13 , 14 , 15 , 16 ]. The last method is solid-state methods, and these are AM methods with powder metallurgy [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ].…”