Duck Bong Kim

• Ph.D.
• Professor (Assistant) at Tennessee Technological University

Additive Manufacturing (AM) promises great potential benefits for industrial manufacturers who require low volume and functional, highly complex, end-use products. Commercial adoption of AM has been slow due to factors such as quality control, production rates, and repeatability. However, given AM's potential, numerous research efforts are underway...

Additive manufacturing (AM) has been envisioned by many as a driving factor of the next industrial revolution. Potential benefits of AM adoption include the production of low-volume, customized, complicated parts/products, supply chain efficiencies, shortened time-to-market, and environmental sustainability. Work remains, however, for AM to reach t...

A bimetallic additively-manufactured structure (BAMS) is a type of functionally-graded multi-material structure used for achieving different complementary material properties within the same structure as well as cost optimization. Wire + arc additive manufacturing (WAAM) offers the capability to fabricate the BAMS in a simultaneous or sequential wa...

Purpose Wire + arc additive manufacturing (WAAM) uses existing welding technology to make a part from metal deposited in an almost net shape. WAAM is flexible in that it can use multiple materials successively or simultaneously during the manufacturing of a single component. Design/methodology/approach In this work, a gas metal arc welding (GMAW)...

This paper describes an approach that can compose predictive models from disparate knowledge sources in smart manufacturing environments. The capability to compose disparate models of individual manufacturing components with disparate knowledge sources is necessary in manufacturing industry, because this capability enables us to understand, monitor...

As manufacturing transitions into the era of Industry 5.0, the demand for systems that are not only intelligent but also human-centric, resilient, and sustainable is becoming increasingly critical. This paper introduces the Human and Humanoid-in-the-Loop (HHitL) ecosystem, a novel framework that integrates both humans and humanoid robots as collabo...

Digital Twin (DT) technology has evolved to contextualize real-time interactions between the physical and digital worlds. It has gained increasing attention in various research areas and industries, including the manufacturing, aerospace, and automotive industries, while facing challenges in processing and analyzing large datasets. To address these...

This study investigates the fabricability, microstructures, and mechanical properties of multi-material structures composed of W7Ni3Fe tungsten alloy and SS316L stainless steel using a wire-arc directed energy deposition process. Direct deposition of SS316L onto W7Ni3Fe substrate resulted in cracks at the edges of the structure, caused by residual...

Additive Manufacturing (AM) is a pivotal technology for transforming complex geometries with minimal tooling requirements. Among the several AM techniques, Wire Arc Additive Manufacturing (WAAM) is notable for its ability to produce large metal components, which makes it particularly appealing in the aerospace sector. However, precise control of th...

This study evaluates the effectiveness of hot isostatic pressing (HIP) in mitigating porosity in TZM-NbZr1 bimetallic structures fabricated via wire-arc directed energy deposition (DED). Two distinct HIP conditions and a combined HIP and heat treatment (HT) were investigated. The pore area fraction decreased from 4 ± 0.05% in the as-built condition...

This study reported the fabrication of bimetallic structures (BS) from tungsten alloy (90WNiFe) and nickel alloy (In625) via wire-arc directed energy deposition (DED)-based additive manufacturing (AM). Its microstructures and mechanical properties were investigated for three different heat input conditions: low (180A), medium (200A), and high (220A...

This paper introduces the concept of human-in-the-loop in smart manufacturing (H-SM), which aims to involve humans more extensively by utilizing advanced technologies such as artificial intelligence, wearable devices, and immersive technologies. The ultimate objective of H-SM, based on the five pillars of intelligence, integration, interoperability...

This study aims to investigate surface roughness, microstructure, and mechanical properties of overhead thin-wall structures of stainless steel(SS316L) fabricated by cold metal transfer (CMT)-based wire + arc additive manufacturing (WAAM). In the first stage, single-layer bead experiments were carried out in flat and overhead positions utilizing Bo...

This paper proposes a conceptual architecture of digital twin with human-in-the-loop-based smart manufacturing (DH-SM). Our proposed architecture integrates cyber-physical systems with human spaces, where artificial intelligence and human cognition are employed jointly to make informed decisions. This will enable real-time, collaborative decision-m...

Wire arc additive manufacturing is a promising additive manufacturing process because of its high deposition rate, and material diversity. However, the low quality of melted parts is a critical issue, owing to the difficulty in establishing design rules for process–structure–property–performance. Previous studies have resolved this challenge by der...

Wire arc additive manufacturing (WAAM) has gained attention as a feasible process in large-scale metal additive manufacturing due to its high deposition rate, cost efficiency, and material diversity. However, WAAM induces a degree of uncertainty in the process stability and the part quality owing to its non-equilibrium thermal cycles and layer-by-l...

Resistance element welding (REW) has recently attracted increasing interest, especially in the joining of high-strength steels and aluminum alloys. However, the intensity of heat input is a critical factor for the joint quality due to the possibility of excessive melting of the aluminum sheet around the element shank, which often degrades the joint...

Herein, the feasibility of the gas tungsten arc welding‐based wire + arc additive manufacturing process for fabricating thin wall structures of niobium‐1 wt% zirconium (NbZr1) alloy is investigated. Three different heat input conditions (low, medium, and high) have been selected for fabricating it. The microstructure is characterized by using optic...

Titanium‑zirconium‑molybdenum (TZM), one of the refractory alloys, has extraordinary physicochemical properties, making it ideal for usage in extreme environmental applications (e.g., high-temperature and nuclear). Due to the scalability and near-net shape fabrication, metal additive manufacturing processes have several advantages, leading it to be...

Three types of self-piercing riveting (SPR) joints, i.e., steel/aluminum, carbon fiber reinforced polymer (CFRP)/aluminum, and aluminum/aluminum, were constructed using three different top sheet materials with the same aluminum alloy as the bottom sheet. The effects of the top sheet material on the joint quality and mechanical behavior were evaluat...

In recent years, manufacturing industries (e.g., medical, aerospace, and automobile) have been changing their manufacturing process to small-quantity batch production to flexibly cope with fluctuations in demand. Therefore, many companies are trying to produce products by introducing 3D printing technology into the manufacturing process. The 3D pri...

This study presents a bimetallic additively manufactured structure (BAMS) of Inconel 625 (In625) and austenitic stainless steel 316L (SS316L) manufactured by a gas-metal-arc-welding (GMAW) based on wire-arc additive manufacturing (WAAM) technology. A BAMS was heat treated at 970 °C for improvement of the mechanical properties. The heat treatments r...

Wire arc additive manufacturing (WAAM) has received attention because of its high deposition rate, low cost, and high material utilization. However, quality issues are critical in WAAM because it builds upon arc welding technology, which can result in low precision and poor quality of the melted parts. Hence, anomaly detection is essential for iden...

The goal of this study is to investigate the wire + arc additive manufacturing (WAAM) of a high-entropy alloy (HEA) and to identify the near-optimal process parameters. To achieve the goal, a two-stage investigation is attempted using pre-alloyed and extruded Al0.1CoCrFeNi wire. In the first stage, single-layer beads are deposited with a range of p...

Purpose Due to the complexity of and variations in additive manufacturing (AM) processes, there is a level of uncertainty that creates critical issues in quality assurance (QA), which must be addressed by time-consuming and cost-intensive tasks. This deteriorates the process repeatability, reliability and part reproducibility. So far, many AM effor...

This study investigates the mechanical properties of the wire + arc additively manufactured Inconel 625 thin wall. The first part of this study focused on the microstructural features of the material after time-based annealing. This second part discusses the tensile strength and microhardness of the material after the same annealing procedure (980...

Bimetallic additively manufactured structures (BAMSs) can replace traditionally-fabricated functionally-graded-components through fusion welding processes and can eliminate locally deteriorated mechanical properties arising from post-processing. The present work fabricates a BAMS by sequentially depositing the austenitic stainless-steel and Inconel...

Wire + arc additive manufacturing (WAAM) is considered an innovative technology that can change the manufacturing landscape in the near future. WAAM offers the benefits of inexpensive initial system setup and a high deposition rate for fabricating medium- and large-sized parts such as die-casting tools. In this study, AISI H13 tool steel, a popular...

This paper presents a systematic methodology to enable environmental sustainability and productivity performance assessment for integrated process and operation plans at the machine cell level of a manufacturing system. This approach determines optimal process and operation plans from a range of possible alternatives that satisfy the objectives and...

Wire + arc additive manufacturing (WAAM) is a versatile, low-cost, energy-efficient technology used in metal additive manufacturing. This WAAM process uses arc welding to melt a wire and form a three-dimensional (3D) object using a layer-by-layer stacking mechanism. In the present study, a Ni-based superalloy wire, i.e., Inconel 625, is melted and...

In this paper, weldability of cold metal transfer (CMT) gas metal arc welding is studied for welding conditions with gap and offset for two different wire composition and strength. The two wires used have different surface tensions and viscosities due to the presence of differing amounts of sulfur and titanium, respectively. The difference in stren...

Purpose Additive manufacturing (AM) processes are the integration of many different science and engineering-related disciplines, such as material metrology, design, process planning, in-situ and off-line measurements and controls. Major integration challenges arise because of the increasing complexity of AM systems and a lack of support among vendo...

This paper investigates the potential advantages and difficulties of integrating predictive model equations in models of unit manufacturing processes. The method described uses metamodels and semantic web technology to relate equations, as objects, to downstream activities. The potential advantages of this include enhanced knowledge refinement and...

The ability to predict performance of manufacturing equipment during early stages of process planning is vital for improving efficiency of manufacturing processes. In the metal cutting industry, measurement of machining performance is usually carried out by collecting machine-monitoring data that record the machine tool’s actions (e.g. coordinates...

This article describes a model-based approach for defining and refining process parameters in dynamically changing, smart manufacturing environments. This approach uses equation-based models to predict how part quality will respond to changes in that environment. The results from these models provide the major inputs into a process-parameter-optimi...

Additive Manufacturing (AM) processes intertwine aspects of many different engineering-related disciplines, such as material metrology, design, in-situ and off-line measurements, and controls. Due to the increasing complexity of AM systems and processes, data cannot be shared among heterogeneous systems because of a lack of a common vocabulary and...

A spectral-based method can acquire and represent the surface appearance of a given material physically correctly. But, it has drawbacks due to its high measurement cost and a long computation time in measuring, modeling, and rendering. In this article, we present spectral recovery and representation of spectral bidirectional reflectance distributi...

It is difficult to formulate and solve optimization problems for sustainability performance in manufacturing. The main reasons for this are: (1) optimization problems are typically complex and involve manufacturing and sustainability aspects, (2) these problems require diversity of manufacturing data, (3) optimization modeling and solving tasks req...

Life cycle assessment (LCA) frameworks are widely used to assess the sustainability of manufacturing processes. Although they have several advantages such as systematic estimation and efficiency, they have significant limitations due to a lack of functionality to perform sustainability analysis. Specifically, they do not fully support dynamic and d...

Sustainable manufacturing has significant impact on a company's business performance and competitiveness in today's world. A growing number of manufacturing indus-tries are initiating efforts to address sustainability issues; however, to achieve a higher level of sustainability, manufac-turers need methodologies for formally describing, analyz-ing,...

An accurate characterization method for a multispectral high-dynamic-range (HDR) imaging system is proposed by combining multispectral and HDR imaging technologies. The multispectral HDR imaging system, which can acquire the visible spectrum at many wavelength bands, can provide an accurate color reproduction and physical radiance information of re...

Energy is considered as one of the important factors for manufacturers to achieve the sustainability objective. To improve energy efficiency in manufacturing, optimization techniques are essential to provide decision support. However, formulating and solving energy optimization in manufacturing is still time-consuming and difficult due to its compl...

Sustainable manufacturing (SM) continues to grow in importance. However, analysis tools to assess the sustainability performance of SM processes are difficult to verify and validate. Additionally, the ability to share and reuse SM information is hampered by a lack of (1) standards to represent that information, (2) interoperability among the engine...

Sustainable manufacturing has become an emerging environmental, economic, societal, and technological challenge to the industry, the academia, and the government entities. Numerous research and development (R&D) efforts have been launched, and many global and domestic efforts have been initiated toward a long-term sustainable world. This paper prov...

This paper presents a comprehensive and efficient framework for computer-aided appearance design based on BRDF (bidirectional reflectance distribution function) measurements. It covers all stages of a new product development including acquisition, processing and modeling of reflectance data, interactive rendering and evaluation of material appearan...

Surface splat, one of the point-based rendering primitives, has offered a powerful alternative to triangle meshes when it comes to the rendering of highly complex objects due to its potential for high-performance and high-quality rendering. Recently, the technological advance of 3D scanners has made it possible to acquire color as well as geometry...

Metallic paint has been widely used to provide for special visual appearance to various products so that photorealistic rendering of this material has been an important issue in the development of new products. We introduce a new approach that predicts the reflectance of metallic paint while considering manufacturing parameters. Our main idea is to...

This paper deals with a method to effectively compress the measured reflectance data of pearlescent paints. In order to simulate the coated surface realistically, it is requested to measure the reflectance of the pearlescent paints by using multiple wavelengths. The wavelength-based reflectance data requests a large amount of storage. However, we c...

Most recent bidirectional reflectance distribution function (BRDF) measurement systems are the image-based that consist of a light source, a detector, and curved samples. They are useful for measuring the reflectance properties of a material but they have two major drawbacks. They suffer from high cost of BRDF acquisition and also give inaccurate r...

In developing new personal electronic products, the development time has shortened to a few months due to high competition in the market. Now it has become very hard to meet the time to market by evaluating products by making physical prototypes. To overcome this problem, we propose an immersive modeling system (IMMS) that enables us to interact wi...

The use of pearlescent paints has grown significantly for many industrial products, due to their special visual effect, which originates from optical interference between many small pearlescent platelets. This makes the visual appearance of pearlescent paints vary with the light and view direction. Since pearlescent paints are very sensitive to spe...

Pearlescent coatings have been widely used in various industrial products such as automotive paints and plastics coatings since it generates special visual appearance called the angle-dependent color shift effect. Curved objects painted with these coatings would be viewed and illuminated from many different directions, and this feature makes the vi...

We present a novel high-dynamic-range (HDR) camera-based bidirectional reflectance distribution function (BRDF) measurement system that can measure the reflectance property of isotropic materials. Our developed system can measure the BRDF of highly specular materials much faster than previous systems. It measures highly dense BRDF samples for a wid...

We present a novel image-based BRDF (Bidirectional Reflectance Distribution Function) measurement system for materials that have isotropic reflectance properties. Our proposed system is fast due to simple set up and automated operations. It also provides a wide angular coverage and noise reduction capability so that it achieves accuracy that is nee...

Many surfaces used in practice consist of combinations of various features that are sufficiently smooth or highly detailed. In the presence of highly detailed features, it is obvious that non-feature-sensitive sampling is unable to preserve small features after significant data reduction. The higher the sensibility of point sampling to small featur...

Recently, the technological advance of 3D depth sensors such as the Z-Cam[1] has made it possible to acquire a dynamic real object in real time(See Fig 1.(a)). The raw depth image is time-consuming to generate connectivity or pre-computed hierarchical data structure from the heavy data set in order to perform graphic and haptic interaction. In this...

Point-based rendering has offered a powerful alternative to triangle meshes when it comes to the rendering of highly complex objects consisting of densely sampled point clouds due to its flexibility and sim- plicity. The technological advance of 3D scanners has made it possible to acquire color as well as geometry data of highly complex objects. Ho...