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Typically, before constructing an object with an additive manufacturing system, the 3D object must be sent through a process called slicing. Slicing converts a 3D object commonly in the form of an STL file into a set of layers by horizontally intersecting a plane with the object at various heights. At each height, called a layer, multiple 2D polygons can be generated. Each polygon represents a boundary for solid geometry and is called an island. Each island is then comprised of multiple path types in an attempt to optimally fill the polygon. To move between each island and each islands’ paths, travels are inserted. Travels are simply motion by the system to move from one area of construction to another. Travels do not contribute to the construction of the object, and so, are considered wasted motion. In large-scale additive manufacturing, objects can be quite large and the distance between islands can be large as well. As a result, these travels can waste a significant amount of time. Ideally, travels would be as short as possible, however, computing global minimal travel paths is computationally expensive. To combat this problem, researchers at Oak Ridge National Lab developed a GPU-based approach to travel insertion based on a unique factoradic representation. This representation was then utilized by the GPU to solve the Traveling Salesman Problem (TSP). This algorithm was able to compute global minimal travel paths quickly resulting in faster object construction. A general investigation was also carried out to determine when a GPU vs CPU implementation would be beneficial.

The potential for site-specific, process-parameter control is an attribute of additive manufacturing (AM) that makes it highly attractive as a manufacturing process. The research interest in the functionally grading material properties of numerous AM processes has been high for years. However, one of the issues that slows developmental progress in this area is process planning. It is not uncommon for manual programming methods and bespoke solutions to be utilized for site-specific control efforts. This article presents the development of slicing software that contains a fully automated process planning approach for enabling through-thickness, process-parameter control for a range of AM processes. The technique includes the use of parent and child geometries for controlling the locations of site-specific parameters, which are overlayed onto unmodified toolpaths, i.e., a vector-based planning approach is used in which additional information, such as melt pool size for large-scale metal AM processes, is assigned to the vectors. This technique has the potential for macro- and micro-structural modifications to printed objects. A proof-of-principle experiment is highlighted in which this technique was used to generate dynamic bead geometries that were deposited to induce a novel surface embossing effect, and additional software examples are presented that highlight software support for more complex objects.

Defects can result in a failed part and are costly in terms of time and material. This cost is even greater in the context of large-scale additive manufacturing where the objects can be very large. As a result, a great deal of research has focused on defect identification and mitigation. To address defects during object construction, researchers at Oak Ridge National Laboratory’s Manufacturing Demonstration Facility investigated an in-situ control system comprised of two sensors: a thermal camera and laser profilometer. This control system adjusted material flow and build speed to mitigate three types of defects: low layer times, underfill, and overfill. Several test objects were constructed. The control system was found to adjust build parameters to handle low layer times of approximately 15 seconds and height deviations from -100% underfill (the absence of a layer) to 50% overfill. Within two layers, height deviations could be returned to within 10% of the expected layer height. Further, preliminary results suggest the system can compensate for uneven build surfaces.

Big Area Additive Manufacturing (BAAM) is a large format additive manufacturing (AM) process. The size scale has enabled many new applications for AM. However, at this scale, lack of high print resolution and extruder flowrate control lead to potentially significant geometric deviations in the printed part. This paper examines strategies to improve geometric quality in BAAM parts. Multi-resolution printing, extrusion diversion, and feedforward extruder control are examined herein. These methods were all found to be effective in mitigating phenomena detrimental to geometric part quality on the BAAM process.

Industry 4.0 represents a significant change in manufacturing with the inclusion of such technologies as additive manufacturing and data analytics. In support of these changes, infrared thermal imaging (IR) and very-near infrared (VNIR) have proven invaluable in numerous applications related to additive manufacturing. In this review, these applications will be presented as they relate to polymer and metal-based additive manufacturing processes. Applications including in-situ characterization, post-build analysis, experimental setups, modeling, and machine learning will be covered. With a general overview complete, the review will conclude with a discussion of challenges identified throughout the literature and thoughts on future trends.

This article highlights work at Oak Ridge National Laboratory’s Manufacturing Demonstration Facility to develop closed-loop, feedback control for laser-wire based Directed Energy Deposition, a form of metal Big Area Additive Manufacturing (m-BAAM), a process being developed in partnership with GKN Aerospace specifically for the production of Ti-6Al-4V pre-forms for aerospace components. A large-scale structural demonstrator component is presented as a case-study in which not just control, but the entire 3D printing workflow for m-BAAM is discussed in detail, including design principles for large-format metal AM, toolpath generation, parameter development, process control, and system operation, as well as post-print net-shape geometric analysis and finish machining. In terms of control, a multi-sensor approach has been utilized to measure both layer height and melt pool size, and multiple modes of closed-loop control have been developed to manipulate process parameters (laser power, print speed, deposition rate) to control these variables. Layer height control and melt pool size control have yielded excellent local (intralayer) and global (component-level) geometry control, and the impact of melt pool size control in particular on thermal gradients and material properties is the subject of continuing research. Further, these modes of control have allowed the process to advance to higher deposition rates (exceeding 7.5 lb/hr), larger parts (1-meter scale), shorter build times, and higher overall efficiency. The control modes are examined individually, highlighting their development, demonstration, and lessons learned, and it is shown how they operate concurrently to enable the printing of a large-scale, near net shape Ti-6Al-4V component.

Ideally, objects are constructed as quickly as possible; however, short build times for a layer can present an issue. Short layer build times do not provide enough time for the material to cool sufficiently. As a result, an object cannot support its own weight nor deal with overhanging features. Additionally, the generation of support structures may be impractical either due to geometry or, in the case of large-scale polymer additive manufacturing, due to being difficult to remove. To address these issues, researchers at Oak Ridge National Laboratory’s Manufacturing Demonstration Facility investigated the use of a thermal camera mounted to a gantry to collect data on an object under construction. This data provided feedback for an in-situ control system to adjust layer build times. Adjustments were made in the form of additional waiting to allow the material to cool to specific thermal thresholds. This additional cooling time allowed the construction of objects with low layer build times or overhanging features that would have otherwise failed.

Additive manufacturing (AM), more commonly referred to as 3D printing, is revolutionizing the manufacturing industry. With any new technology comes new rules and guidelines for the optimal use of said technology. Big Area Additive Manufacturing (BAAM), developed by Cincinnati Incorporated and Oak Ridge National Laboratory’s Manufacturing Demonstration Facility, requires a host of new design parameters compared to small-scale 3D printing to create large-scale parts. However, BAAM also creates new possibilities in material testing and various applications in the manufacturing industry. Most of the design constraints of small-scale polymer 3D printers still apply to BAAM. Beyond those constraints, new rules and limitations exist because BAAM’s large-scale system significantly changes the thermal properties associated with small-scale AM. This work details both physical and software-related design considerations for additive manufacturing. After reading this guide, one will have a better understanding of slicing software’s capabilities and limitations, different physical characteristics of design and how to apply them appropriately for AM, and how to take the inherent nature of AM into consideration during the design process.

Industry 4.0 represents the next evolution of industrial technology. Some of the key characteristics of Industry 4.0 include augmented reality and additive manufacturing. In support of this evolution, researchers at (blinded) created a prototype augmented reality (AR) interface, ASMARI. This prototype acts as a common interface for both industrial additive and subtractive machines. Additionally, in the changing industrial workspace of Industry 4.0, the role of humans will also change. This interface focuses on increasing productivity and situational awareness, while providing new interaction modalities for interacting with hardware. The prototype was also evaluated by multiple users who provided positive feedback on the system. Ultimately, the prototype represents a first step towards significant integration between augmented reality and additive manufacturing.

Defect identification and mitigation is an important avenue of research to improve the overall quality of objects created using additive manufacturing (AM) technologies. Identifying and mitigating defects takes on additional importance in large-scale, industrial AM. In large-scale AM, defects that result in failed prints are extremely costly in terms of time spent and material used. To address these issues, researchers at Oak Ridge National Laboratory’s Manufacturing Demonstration Facility investigated the use of a laser profilometer and thermal camera to collect data concerning an object as it was constructed. These data provided feedback for an in situ control system to adjust object construction. Adjustments were made in the form of automated height control. This paper presents results for both a polymer- and metal-based system. Object construction for both systems was improved significantly, and the resulting objects were more geometrically identical to the ideal 3D representation.

Virtual human interactions provide an important avenue for training as emergent opportunities arise. In response to a new training need, we propose a framework to rapidly create experiential learning opportunities in the form of a question--answer chat interaction with virtual humans. This framework takes quickly generated case documents and breaks down the case into small tasks that can be crowdsourced by nonexperts. This framework can serve as a first step to rapidly bootstrapping new virtual humans. We have applied our framework to the task of preparing health care students and professionals to infrequent, but high-stakes, situations such as infectious diseases, cranial nerve disorders, and stroke. Our framework was utilized by medical professionals interested in providing new training experiences to students and colleagues. Over the course of two months, these professionals created seven scenarios on a diverse range of topics that included Ebola, cancer, and neurological disorders. These scenarios were developed for multiple target audiences such as medical students, residents, and fellows. As a first step, each scenario utilized our framework and crowdsourced workers to create an initial corpus over the course of two days. From these seven cases, we selected two to evaluate the quality of the resulting virtual-human corpuses. The two scenarios were compared to preexisting reference scenarios that have been in curricular use for several years. We found a reduction in author time commitment of at least 92% while creating a character that was at least 75% as accurate as its reference counterparts. The commitment reduction and accuracy achieved by our framework represents a first step towards rapid development of a virtual human. Our framework can then be combined with other creation processes for further virtual-human development in order to create a mature virtual human. As part of a virtual-human development process, our framework can help to rapidly develop new scenarios in response to emergent training opportunities.

Physician empathy is a complex phenomenon known to improve illness outcomes; however, few tools are available for deliberate practice of empathy. We used a virtual patient (VP) to teach empathic communication to first-year medical students. We then evaluated students' verbal empathy in a standardized patient (SP) interaction.Seventy medical students, randomly assigned to 3 separate study groups, interacted with (1) a control VP portraying depression, (2) a VP with a backstory simulating patient shadowing, or (3) a VP able to give immediate feedback about empathic communication (empathy-feedback VP). Subsequently, the students interviewed an SP portraying a scenario that included opportunities to express empathy. All SP interviews were recorded and transcribed. The study outcomes were (1) the students' verbal response to the empathic opportunities presented by the SP, as coded by reliable assessors using the Empathic Communication Coding System, and (2) the students' responses as coded by the SPs, using a communication checklist.There were no significant differences in student demographics between groups. The students who interacted with the empathy-feedback VP showed higher empathy in the SP interview than did the students in the backstory VP and the control VP groups [mean (SD) empathy scores coded on a 0-6 scale were 2.91 (0.16) vs. 2.20 (0.22) and 2.27 (0.21), respectively). The difference in scores was significant only for the empathy-feedback VP versus the backstory VP group (P = 0.027). The SPs rated the empathy-feedback and the backstory VP groups significantly higher than the control VP group on offering empathic statements (P0.0001), appearing warm and caring (P = 0.015), and forming rapport (P = 0.004).Feedback on empathy in a VP interaction increased students' empathy in encounters with SPs, as rated by trained assessors, whereas a simulation of patient shadowing did not. Both VP interventions increased students' empathy as rated by SPs, compared with the control VP group.

We conducted a study which investigated if we could overcome challenges associated with interpersonal communication skills training by building a virtual human with back story. Eighteen students interacted with a virtual human who provided back story, and seventeen students interacted with the same virtual human who did not provide back story. Back story was achieved through the use of cutscenes which played throughout the virtual human interaction. Cutscenes were created with The Sims 3 and depicted short moments that occurred in the virtual human’s life. We found medical students who interacted with a virtual human with a back story, when interacting with a standardized patient, were perceived by the standardized patient as more empathetic compared to the students who interacted with the virtual human without a back story. The results have practical implications for building virtual human experiences to train interpersonal skills. Providing back story appears to be an effective method to overcome challenges associated with training interpersonal skills with virtual humans.

The study reviews the performance of four transition countries - Albania, Azerbaijan, the Kyrgyz Republic, and Moldova - in the areas of private, and financial sector development, identifying both their achievements, and challenges, to extract beneficial reform efforts, and alternative approaches, setting the pace for sustainable growth. These countries were selected because they are among the poorest in the region, whose problems are seemingly intractable, and have been largely detached from the international marketplace until the transition began. Thus, in terms of history, resource endowment, and proximity to markets they are viewed as "late reformers" in economic development, and competitiveness, despite policy reforms. Enterprise arrears, and soft budget constraints have been a significant problem in many transition economies, more often than not, manifested as some fiscal tightening occurred to offset budget constraints. Hence, a core challenge of the transition is to reduce the role of government from all encompassing presence, towards a professionally managed model, and one which provides high service delivery, strengthens civil institutions, and plays an effective regulatory role in a market economy. This requires improved financial discipline, reasonable fiscal policy, and structural adjustment, while privatization that promotes concentrated outsider ownership, and foreign participation, should be favored.

Many of the distortions in poorly performing economies do not originate in the banking sector, but where state banks still control a large share of the resources in the banking system, they continue to pose a risk to macroeconomic and fiscal stability. State banks are typically vehicles for patronage that worsen the prospects for competitive market development. Alternatively, these state banks can be ineffective shells that fail to perform a useful intermediation role once the government imposes effective hard budget constraints and a modern supervisory system. The most problematic state banks have been agricultural and industrial banks, whose original role was to finance state farms and industrial enterprises that employed large numbers of people and served as the backbone of the socialist economic mode. Banks now show stronger growth in deposits and capital in many countries in Central and Eastern Europe and the Baltics, suggesting that these countries have put into place structures that have helped to restore confidence in banking systems among creditors, investors, and the public. Recommended strategies are that Governments need to design strategies to reduce state banking in order to help create a stable banking environment. Governments should take measures to improve the business environment as part of a broad overall strategy to strengthen the financial system and end state ownership of banks. Such measures include providing support to improve corporate governance, reform judicial systems, build registries of collateral, reinforce creditors' rights and contract enforcement, modernize accounting and auditing practices, reduce administrative obstacles to business registration, and modernize bankruptcy laws.