Additive manufacturing technologies : 3D printing, rapid prototyping, and direct digital manufacturing

This book covers in detail the various aspects of joining materials to form parts. A conceptual overview of rapid prototyping and layered manufacturing is given, beginning with the fundamentals so that readers can get up to speed quickly. Unusual and emerging applications such as micro-scale manufacturing, medical applications, aerospace, and rapid manufacturing are also discussed. This book provides a comprehensive overview of rapid prototyping technologies as well as support technologies such as software systems, vacuum casting, investment casting, plating, infiltration and other systems. This book also: Reflects recent developments and trends and adheres to the ASTM, SI, and other standards Includes chapters on automotive technology, aerospace technology and low-cost AM technologies Provides a broad range of technical questions to ensure comprehensive understanding of the concepts covered.

Simplifying medical additive manufacturing: making the surgeon the designer

Additive Manufacturing, a technology which has been in existence since three decades, is now successfully being transitioned from a research setting to finding technologically and financially viable end-user applications. A key sector in which Additive Manufacturing is being used is the medical devices and healthcare sector. Drivers in this sector include the ability to create customized, patient specific devices and implants with quick turnaround time in a cost-effective manner. Doctors and surgeons are important change agents and innovators in the creation of new healthcare devices as well as surgical methods. Often times, they may find it necessary at first to build devices and plan surgeries which are not even being thought of or acted upon by the major healthcare companies. In this sense, they perform the roles of designers, creating new ideas and improving on them until they can be implemented and adopted by others. However, the scope for performing this creative activity is often limited in their workplaces, with resource, time and financial impediments often being present. Additive Manufacturing can be helpful to speed up the iterative process of designing such medical devices or planning surgeries as well as help convince people outside of the surgery room of the feasibility and business case for such innovations. This paper proposes to introduce a framework of design, processes and tools which will enable non-engineers (specifically surgeons) to create custom-built products. It is hoped that this paper will motivate more surgeons and non-engineers to get involved in the process of designing for additive manufacturing.

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

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.

Additive manufacturing in the cycling industry: mainstream or gimmick?

INTRODUCTION. Additive manufacturing (AM) for various industries has been trailed, prototyped and used in limited production runs (Gibson, 2015). But considering additive manufacturing with metallic materials has been around for over 15 years the penetration into an industry such as cycling that values customisation and progressive design techniques has been quite limited. This case study looks at the potential of and why additive manufacturing has not progressed from concept development and prototyping into production and mainstream. Selective Laser Melting (SLM) additive manufacturing systems mainly use Stainless Steel 316 (SS316) and Titanium 6Al.4V (Ti64) as a baseline material; both these materials are extremely common in the custom and high volume bike industries. For the purposes of this article we will focus on smaller custom bike manufacturers who are typically more agile and open to high levels of customisation in their products. The study finds that whilst a high number of companies will experiment and prototype with additive manufacturing there is little evidence that the design and development process translates to ongoing production for sale to the consumer, this could be due to knowledge of design and fabrication techniques.

Microstructure and mechanical properties of wrought and additive manufactured Ti-6Al-4V cylindrical bars

Titanium alloys are widely used in various engineering design application due to its superior material properties. The traditional manufacturing of titanium products is always difficult, time consuming, high material wastage and manufacturing costs. Selective laser melting (SLM), an additive manufacturing technology has widely gained attention due to its capability to produce near net shape components with less production time. In this technical paper,microstructure,chemical composition,tensile properties and hardness are studied for the wrought and additive manufactured SLM cylindrical bar. Microstructure,mechanical properties and hardness were studied in both the longitudinal and transverse directions of the bar to study the effect of orientation. It was found that additive manufactured bar have higher yield strength, ultimate tensile strength and hardness than the wrought bar. For both conventional and SLM test samples, the yield strength, ultimate tensile strength and hardness was found to be high in the transverse direction. The difference in the properties can be attributed to the difference in microstructure as a result of processing conditions. The tensile fracture area was quantified by careful examination of the fracture surfaces in the scanning electron microscope.

Titanium in biomedical applications—properties and fabrication: a review

Ti and Ti-based alloys have unique properties such as high strength, low density and excellent corrosion resistance. These properties are essential for the manufacture of lightweight and high strength components for biomedical applications. In this paper, Ti properties such as metallurgy, mechanical properties, surface modification, corrosion resistance, biocompatibility and osseointegration in biomedical applications have been discussed. This paper also analyses the advantages and disadvantages of various Ti manufacturing processes for biomedical applications such as casting, powder metallurgy, cold and hot working, machining, laser engineering net shaping (LEN), superplastic forming, forging and ring rolling. The contributions of this research are twofold, firstly scrutinizing the behaviour of Ti and Ti-based alloys in-vivo and in-vitro experiments in biomedical applications to determine the factors leading to failure, and secondly strategies to achieve desired properties essential to improving the quality of patient outcomes after receiving surgical implants. Future research will be directed toward manufacturing of Ti for medical applications by improving the production process, for example using optimal design approaches in additive manufacturing and investigating alloys containing other materials in order to obtain better medical and mechanical characteristics.

A survey on mechanisms and critical parameters on solidification of selective laser melting during fabrication of Ti-6Al-4V prosthetic acetabular cup

Additive Manufacturing (AM) includes a range of approaches that correlate with computer aided design (CAD) and manufacturing by fabrication via precise layers and is a promising method for the production of medical tools. In this study, different aspects and mechanisms of solidification for curved surfaces based on equilibrium at curved interfaces, Monge patch, interfacial and Gibbs energy will be discussed. Also, the effect of capillarity, geometry, substrate temperature, cooling rate and scanning parameters in the solidification of a prosthetic acetabular cup (PAC) using selective laser melting (SLM) is analysed. The contributions of this work are analysing solidification and effective factors in this process to produce parts with a higher quality and mechanical properties such as strength, strain, porosity, relative density and hardness. Results indicate that due to the surface to volume (S/V) ratio, and the increasing effect of the radius on Monge patch, thermal stresses and surface forces are more prevalent on outer surfaces. Moreover, solidification and mechanical properties are related to capillarity, geometry, substrate temperature, cooling rate, scanning power and speed. The results also indicate the interaction of solute diffusion and heat transfer with interatomic forces in large S/V ratio and at small scales tend to improve solidification.

Tool wear and surface integrity analysis of machined heat treated selective laser melted Ti-6Al-4V

In this study, the tool wear and surface integrity during machining of wrought and Selective LaserMelted (SLM) titanium alloy (after heat treatment) are studied. Face turning trails were carried out onboth the materials at different cutting speeds of 60,120 and 180 m/min. Cutting tools and machinedspecimens collected are characterized using scanning electron microscope, surface profiler and opticalmicroscope to study the tool wear, machined surface quality and machining induced microstructuralalterations. It was found that high cutting speeds lead to rapid tool wear during machining of SLMTi-6Al-4V materials. Rapid tool wear observed at high cutting speeds in machining SLM Ti-6Al-4Vresulted in damaging the surface integrity by 1) Deposition of chip/work material on the machinedsurface giving rise to higher surface roughness and 2) Increasing the depth of plastic deformationon the machined sub surface.