Additive manufacturing of materials: Opportunities and challenges

Abstract

Figure 1. Development stages of big-area additive manufacturing (BAAM). (a) Gantrystyle robotic automation system, without any heating environment, was developed and integrated with a single-screw extrusion nozzle. (b) Initial material trials led to extensive distortion with acrylonitrile butadiene styrene (ABS) pellets, whereas use of pellets with ABS and carbon fi ber (CF) reduced the distortion. (c) Aerial view of the industrial-scale BAAM system developed by Local Motors. (d) The industrial-scale system was verifi ed by printing out a chassis of a small car, which was then integrated with an electric drive train. (e) The same technology was coupled with traditional manufacturing to produce a prototype similar to the Ford Shelby Cobra, which was also powered by an electric drive train. (f) The same technology has also been used to make molds for use in prototyping during traditional metal-forming processes. Reproduced with permission from Reference 10.

Overview of Materials Qualification Needs for Metal Additive Manufacturing

“…Melt pool monitoring is being used to capture the distribution of temperature within deposited layers in order to generate a heat map that can be compared to melt pool size. 42,43 However, high bandwidth data acquisition (e.g. 1000 s of Hz) and processing can generate enormous datasets that are difficult to manage while also requiring enormous amounts of data storage (e.g., 1000 s of GB).…”

Modeling the electrical properties of three-dimensional printed meshes with the theory of resistor lattices

“…Three types of numerical calculations are presented: (1) calculations with l = 60 continued-fraction levels using the minimum value of termination parameter, s = b l ; (2) calculations still with l = 60 and the termination parameter s = 2.01426 adjusted to get the correct value of the first-neighbor equivalent resistance (+OT); (3) calculations with the core-shell model, now with l = 200, the boundary shell having a thickness of 25 resistors and a bond resistance R 1 = 0.56351 (+BS). In the latter calculations, s = b l is used, as in calculations (1).…”

“…(1,0) 0.50000000 0.00002400 0.00000001 0.00000010 (2,0) 0.72676045 0.00011439 0.00001083 0.00000026 (4,0) 0.95398729 0.00044407 0.00003788 0.00000317 (1,1) 0.63661977 0.00005752 0.00001311 0.00000025 (2,2) 0.84882636 0.00022619 0.00002047 0.00000062 (4,4)…”

“…Three-dimensional (3D) printers make it possible to design unprecedented structures with a geometry specially designed to reach specific properties [1]. For example, the making of lightweight periodic cellular architectures by 3D printing has been demonstrated [2].…”

Neutron Imaging of Laser Melted SS316 Test Objects with Spatially Resolved Small Angle Neutron Scattering

“…A 2015 review of metal additive manufacturing notes the rapid growth in applications as well as two significant problems, lack of crystal growth control and excess gas porosity within the metal object [1]. Porosity characterization strategies have been explored for cobalt-chrome objects produced with direct metal laser sintering [2].…”