The past few decades have seen substantial growth in Additive Manufacturing (AM) technologies. However, this growth has mainly been process-driven. The evolution of engineering design to take advantage of the possibilities afforded by AM and to manage the constraints associated with the technology has lagged behind. This paper presents the major opportunities, constraints, and economic considerations for Design for Additive Manufacturing. It explores issues related to design and redesign for direct and indirect AM production. It also highlights key industrial applications, outlines future challenges, and identifies promising directions for research and the exploitation of AM's full potential in industry.

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Design for additive manufacturing: trends, opportunities, considerations, and constraints

House of Quality

Design for manufacture and assembly (DFM) has typically meant that designers should tailor their designs to eliminate manufacturing difficulties and minimize manufacturing, assembly, and logistics costs. However, the capabilities of additive manufacturing technologies provide an opportunity to rethink DFM to take advantage of the unique capabilities of these technologies. As mentioned in Chap. 16, several companies are now using AM technologies for production manufacturing. For example, Siemens, Phonak, Widex, and the other hearing aid manufacturers use selective laser sintering and stereolithography machines to produce hearing aid shells; Align Technology uses stereolithography to fabricate molds for producing clear dental braces (“aligners”); and Boeing and its suppliers use polymer powder bed fusion (PBF) to produce ducts and similar parts for F-17 fighter jets. For hearing aids and dental aligners, AM machines enable manufacturing of tens to hundreds of thousands of parts, where each part is uniquely customized based upon person-specific geometric data. In the case of aircraft components, AM technology enables low-volume manufacturing, easy integration of design changes and, at least as importantly, piece part reductions to greatly simplify product assembly.

Design for Additive Manufacturing

Recent advances in modelling of metal machining processes

During the resorbable-polymer-boom of the 1970s and 1980s, polycaprolactone (PCL) was used in the biomaterials field and a number of drug-delivery devices. Its popularity was soon superseded by faster resorbable polymers which had fewer perceived disadvantages associated with long term degradation (up to 3-4 years) and intracellular resorption pathways; consequently, PCL was almost forgotten for most of two decades. Recently, a resurgence of interest has propelled PCL back into the biomaterials-arena. The superior rheological and viscoelastic properties over many of its aliphatic polyester counterparts renders PCL easy to manufacture and manipulate into a large range of implants and devices. Coupled with relatively inexpensive production routes and FDA approval, this provides a promising platform for the production of longer-term degradable implants which may be manipulated physically, chemically and biologically to possess tailorable degradation kinetics to suit a specific anatomical site. This review will discuss the application of PCL as a biomaterial over the last two decades focusing on the advantages which have propagated its return into the spotlight with a particular focus on medical devices, drug delivery and tissue engineering.

The return of a forgotten polymer : Polycaprolactone in the 21st century

Investigation and FEM-based simulation of tool wear in turning operations with uncoated carbide tools

Multi-layered Scaffolds Production via Fused Deposition Modeling (FDM) Using an Open Source 3D Printer: Process Parameters Optimization for Dimensional Accuracy and Design Reproducibility

https://escholarship.org/content/qt8sh4s45p/qt8sh4s45p.pdf?t=phrr6d

Electrospinning and characterization of polymer–graphene powder scaffolds

Additive manufacturing (AM) is a layer-by-layer fabrication process for producing complex parts with a high design flexibility. In particular, the interest in AM is growing in many fields, especially for fabricating highly customized parts. One of the most widespread AM techniques is fused deposition modelling (FDM), but an important limit for this technology is the low surface finishing. Therefore, the enhancement of the surface roughness of parts produced by FDM represents one of the main research challenges in this field. Several approaches have been proposed and the use of solvent for chemical finishing treatments has a great potentiality. The present research investigates the surface post-treatment process with cold vapours of dimethyl ketone (acetone) for 3D printed parts made in ABS and produced by FDM. In particular, the study focuses on the capability of the treatment in enhancing the surface finishing in terms of surface roughness, uniformity and treatment time. A full range of initial surface roughness were treated considering two different process setups and analysing the roughness evolution over the treatment time. Results showed a 98% reduction of the roughness within the post-treatment. Moreover, the most stable configuration was identified. Finally, the research outlined a map of the process which correlates the achievable surface finishing with the initial roughness of the part and with the treatment time.

Characterization of chemical surface finishing with cold acetone vapours on ABS parts fabricated by FDM

Incremental sheet forming is a technique that allows locally deforming a sheet by means of a movable punch. Even if it requires longer forming time and higher part geometrical tolerances with respect to traditional sheet forming techniques, it does not need dedicated devices and its accuracy can be improved adopting low cost full or partial dies. For these reasons, it results to a flexible technology and economically suitable for low volume batch productions such as pre-series, prototypes or high customised parts. These characteristics well fit with prosthesis manufacturing where each part is a unique product, indeed its geometry needs to meet the patient’s physical characteristics. In the present paper, titanium ISF formed parts will be studied, in particular surface anodising pre-treatment effects on part finishing and biocompatibility are investigated.

Antonio Fiorentino

Papers

Investigation and FEM-based simulation of tool wear in turning operations with uncoated carbide tools

Multi-layered Scaffolds Production via Fused Deposition Modeling (FDM) Using an Open Source 3D Printer: Process Parameters Optimization for Dimensional Accuracy and Design Reproducibility

Electrospinning and characterization of polymer–graphene powder scaffolds

Characterization of chemical surface finishing with cold acetone vapours on ABS parts fabricated by FDM

Preliminary results on Ti incremental sheet forming (ISF) of biomedical devices: biocompatibility, surface finishing and treatment