Background: 3D-printed patient-specific anatomical models are becoming an increasingly popular tool for planning reconstructive surgeries to treat oral cancer. Currently there is a lack of information regarding model accuracy, and how the resolution of the computed tomography (CT) scan affects the accuracy of the final model. Purpose: The primary objective of this study was to determine the CT z-axis resolution necessary in creating a patient specific mandibular model with clinically acceptable accuracy for global bony recon-struction. This study also sought to evaluate the effect of the digital sculpting and 3D printing process on model accuracy. Study Design: This was a cross-sectional study using cadaveric heads obtained from the Ohio State Uni-versity Body Donation Program.Independent Variables: The first independent variable is CT scan slice thickness of either 0.675 , 1.25, 3.00, or 5.00 mm. The second independent variable is the three produced models for analysis (unsculpted, digitally sculpted, 3D printed).Main Outcome Variable: The degree of accuracy of a model as defined by the root mean square (RMS) value, a measure of a model's discrepancy from its respective cadaveric anatomy.Analyses: All models were digitally compared to their cadaveric bony anatomy using a metrology surface scan of the dissected mandible. The RMS value of each comparison evaluates the level of discrepancy. One-way ANOVA tests (P < .05) were used to determine statistically significant differences between CT scan resolutions. Two-way ANOVA tests (P < .05) were used to determine statistically significant differences between groups.Results: CT scans acquired for 8 formalin-fixed cadaver heads were processed and analyzed. The RMS for digitally sculpted models decreased as slice thickness decreased, confirming that higher resolution CT scans resulted in statistically more accurate model production when compared to the cadaveric gold standard. Furthermore, digitally sculpted models were significantly more accurate than unsculpted models (P < .05) at each slice thickness.Conclusions: Our study demonstrated that CT scans with slice thicknesses of 3.00 mm or smaller created statistically significantly more accurate models than models created from slice thicknesses of 5.00 mm. The digital sculpting process statistically significantly increased the accuracy of models and no loss of accuracy through the 3D printing process was observed.(c) 2023 American Association of Oral and Maxillofacial SurgeonsJ Oral Maxillofac Surg 81:1176-1185, 2023

PurposeLoss of corneal transparency is one of the major causes of visual loss, generating a considerable health and economic burden globally. Corneal transplantation is the leading treatment procedure, where the diseased cornea is replaced by donated corneal tissue. Despite the rise of cornea donations in the past decade, there is still a huge gap between cornea supply and demand worldwide. 3D bioprinting is an emerging technology that can be used to fabricate tissue equivalents that resemble the native tissue, which holds great potential for corneal tissue engineering application. This study evaluates the manufacturability of 3D bioprinted acellular corneal grafts using low-cost equipment and software, not necessarily designed for bioprinting applications. This approach allows access to 3D printed structures where commercial 3D bioprinters are cost prohibitive and not readily accessible to researchers and clinicians.MethodsTwo extrusion-based methods were used to 3D print acellular corneal stromal scaffolds with collagen, alginate, and alginate-gelatin composite bioinks from a digital corneal model. Compression testing was used to determine moduli.ResultsThe printed model was visually transparent with tunable mechanical properties. The model had central radius of curvature of 7.4 mm, diameter of 13.2 mm, and central thickness of 0.4 mm. The compressive secant modulus of the material was 23.7 & PLUSMN; 1.7 kPa at 20% strain. 3D printing into a concave mold had reliability advantages over printing into a convex mold.ConclusionsThe printed corneal models exhibited visible transparency and a dome shape, demonstrating the potential of this process for the preparation of acellular partial thickness corneal replacements. The modified printing process presented a low-cost option for corneal bioprinting.

The desire to industrialize and expand the envelope of L-PBF additive manufacturing has driven development of Multi-Laser Powder Bed Fusion (ML-PBF) technology. Stitching of large parts by multiple lasers has become a reality, but the material effects have yet to be well understood. This study examines the differences in mechanical properties and microstructures for stitched and nominal, single laser exposed zones in Nickel-base alloy 718 produced via L-PBF. Multiple industry-relevant heat treatments were examined including stress relief, hot isostatic pressing (HIP), solution heat treatment, and aging. A range of responses between the stitched and nominal zones with each heat treatment have been determined. The addition of an 1120 degrees C HIP cycle eliminated most signs of heterogeneity between the two zones and provides a promising avenue for industrial adoption.

Additive manufacturing (AM) has captured the imagination of the manufacturing community and has revolutionary potential across a number of energy applications. One particular challenge for these applications is the large size of metal AM components that are compelling to be printed. This necessitates welding and joining processes to integrate metal AM parts into larger assemblies, as well as the ability to repair and re-work metal AM parts that may have defects. This work characterizes the microstructural and mechanical properties of metal parts produced through laser-based powder bed fusion (L-PBF) and electron beam powder bed fusion (EB-PBF) and then subsequently welded. The results show possibilities for gas tungsten arc welding (GTAW) and friction stir welding (FSW) as feasible rework and repair solutions for AM-printed AlSi10Mg, Ni 718, and Ti64. More research attention to this area will improve the viability of L-PBF and electron beam melting AM technology for energy applications.

To share the latest trends on how additive manufacturing is impacted by new data-driven technologies, three industry leaders will be part of a panel discussion at IMAT 2020 on Artificial Intelligence/Machine Learning and Additive Manufacturing. The session, organized by the ASM Emerging Technologies Awareness Committee, will be moderated by Hanchen Huang, dean of engineering at University of North Texas. Following is an informal discussion by the panelists, which provides a glimpse into the state of AI/ML and AM and a preview of their more formal panel discussion scheduled for this fall.

In the last paragraph of the section “SOLIDIFICATION AND THERMODYNAMIC SIMULATIONS”, the authors would like to change the sentence “Although the solvus temperature for δ was not predicted here, it should be near the non-equilibrium solidus temperature as it forms during the terminal stages of solidification” to “Although the solvus temperature for Laves was not predicted here, it should be near the non-equilibrium solidus temperature as it forms during the terminal stages of solidification”.

The potential benefits of metal additive manufacturing, as compared with more traditional, subtractive-only approaches, has created excitement within design circles seeking to take advantage of the ability to build and repair complex shapes, to integrate or consolidate multiple parts and minimize joining concerns, and to locally tailor material properties to increase functionality. Tempering the excitement of designers, however, has been concerns with the material deposited by the process. It is not enough for a part to ‘look’ right from a geometric perspective. Rather, the metallurgical aspects associated with the material being deposited must ‘look’ and ‘behave’ correctly along with the aforementioned geometric accuracy. Finally, without elucidation of the connections between processing, microstructure, properties, and performance from a materials science perspective, metal additive manufacturing will not realize its potential to change the manufacturing world for property and performance-critical engineering applications.

Edward D. Herderick is the JOM advisor for the Process Technology & Modeling Committee of the TMS Extraction & Processing Division and the Materials Processing & Manufacturing Division, and guest editor for the topic Progress in Additive Manufacturing in this issue.

Additive manufacturing (AM) is among the fastest growing and most talked about manufacturing technologies on the planet. It is providing diverse opportunities for new product design and manufacturing. At GE, efforts such as the additively produced LEAP engine fuel nozzle and low-pressure turbine blade manufacturing are examples of how GE Aviation is leveraging these technologies in innovative ways. These are just a few illustrations of how AM is changing the manufacturing landscape and many others are described in the articles that follow. This rapid growth and investment poses several questions for the minerals, metals, and materials community: What exactly is ‘‘additive manufacturing?’’ Why has it captured the manufacturing industry imagination? How can the TMS community of materials and process technologists and leaders contribute to its growth and implementation? At its core, AM is a suite of technologies that ‘‘build’’ components using digital model data. The ASTM Committee F42 on AM Technologies has defined seven different process routes as being part of the field of AM. Each process has its own unique benefits and challenges that derive from the thermal and chemical processing cycle and the resulting microstructure. Any discussion of the technology needs to take into account the details of the resulting materials microstructure, surface roughness, and ability to maintain engineering tolerances, as well as implementation details about reliability and cost, and potential supply chain issues. The industrial excitement around this suite of processes is being driven by its capacity for empowering designers to focus on designing components for functionality rather than limitations of conventional processes such as casting, brazing, or forming processes. Furthermore, it is now enabling a whole new paradigm of rapid testing and product introduction wherein functional metal prototypes can be used for testing of individual components and manufacturing assembly processes (e.g., joining, forming, or machining). Using AM means product development cycles do not have to rely on traditional methods for manufacturing metallic prototypes, which can take months to produce. This leads to the key question: How can the minerals, metals, and materials community contribute to responsible, accelerated growth given the context of where the field is today? The key to industrial implementation for manufacturing technologies is a thorough understanding of the synergistic interaction of materials and processes. For AM, there are currently only a handful of materials and processes that are well understood, such as the previously mentioned laser powder-bed fusion of cobalt chrome and electron beam powder-bed fusion of titanium aluminide. To realize the full potential of AM, further maturation of the processing-structure-properties linkages will be required in a broader set of metal alloys and for many more processing approaches. When that happens, AM adoption will accelerate as industrial designers become empowered to select tailored material and process combinations that drive performance improvement for demanding applications. This special topic, Progress in AM, strives to meet that challenge by presenting a collection of articles that cover a broad spectrum of material systems and AM processing approaches including original research topics and application reviews. To download any of the articles, follow the URL: http://link.spring er.com/journal/11837/67/3/page/1 to the table of contents page for the March 2015 issue (Vol. 67, No. 3). In ‘‘Metallurgical and Mechanical Evaluation of 4340 Steel Produced by Direct Metal Laser Sintering,’’ by Elias Jelis, Matthew Clemente, Stacey Kerwien, Nuggehalli M. Ravindra, and Michael R. Hespos, the authors present new work on the Edward D. Herderick is the guest editor for the Process Technology and Modeling Committee of the TMS Materials Processing & Manufacturing Division, and coordinator of the topic Progress in Additive Manufacturing in this issue. JOM, Vol. 67, No. 3, 2015