Sangkee Min

University of Wisconsin–Madison | UW · Department of Mechanical Engineering

With the growing demand for the fabrication of microminiaturized components, a comprehensive understanding of material removal behavior during ultra-precision cutting has become increasingly significant. Single-crystal sapphire stands out as a promising material for microelectronic components, ultra-precision lenses, and semiconductor structures ow...

As the most promising and advanced technology, ultra-precision machining (UPM) has dramatically increased its production volume for wide-range applications in various high-tech fields such as chips, optics, microcircuits, biotechnology, etc. The concomitantly negative environmental impact resulting from huge-volume UPM has attracted unprecedented a...

The ultra-precision machine tool industry has been consistently improving to the point where machine tools with extreme thermal controls, vibration damping, and command resolutions of 0.1 nm are commercially available. As little research focus has been given to developing peripheral technologies, currently available work coordinate system setting m...

Detection and localization of activities in a human-centric manufacturing assembly operation will help improve manufacturing process optimization. Through the human-in-loop approach, the step time and cycle time of the manufacturing assemblies can be continuously monitored thereby identifying bottlenecks and updating lead times instantaneously. Aut...

The ultra-precision machine tool industry has been consistently improving to the point where machine tools with extreme thermal controls, vibration damping, and command resolutions of 0.1 nm are commercially available. As little research focus has been given to developing peripheral technologies, currently available work coordinate system setting m...

Single-crystal sapphire is used in various fields of industry due to its superior mechanical, optical, and chemical properties, but fabricating sapphire is challenging because of its high hardness and brittleness. Ultra-precision machining (UPM) has been studied as one of the solutions to overcome these issues as it facilitates cutting of brittle c...

Work coordinate setup in an ultra-precision machine tool is one of the important tasks to fabricate a structure at the desired position with high accuracy. Setting up the work coordinate is very challenging because it requires high precision, direct measurement, and non-contact preferred. This paper proposes a new method to measure the relative dis...

Ability to detect faults in manufacturing machines have become crucial in the era of Smart Manufacturing to enable cost savings from erratic downtimes, in an effort towards Green Manufacturing. The power consumption data provides myriad of information that would facilitate condition monitoring of manufacturing machines. In this work, we retrofit an...

Ductile regime cutting has been studied to process brittle materials without cracking. The predominant material response during cutting can be tuned to the ductile range under certain conditions. This study aims to explore and reveal the effects of workpiece surface coatings on promoting the ductile cutting regime. Despite of several attempts on ap...

Ultra-precision machine tools are the foundation for ultra-precision manufacturing. In the era of Industry 4.0, monitoring the machine tool’s working condition is critical to control the machining quality. In a conventional setting, numerous sensors are retrofitted to the machine to monitor its condition effectively. This process could potentially...

Lithium-ion batteries (LIBs) require Ni-rich cathode material with a high capacity to meet the growing demand for powering electric vehicles and other energy-dense devices. However, significant challenges remain to improve capacity retention during cycling and thermal-abuse tolerance of this material. Alternative to the traditional polycrystalline...

Single-crystal sapphire can be used in various fields in the industry due to its superior material properties, but it has been challenging to fabricate sapphire parts with high accuracy and complexity because of its high hardness and brittleness, which lead to crack generation during the machining process. Ultra-Precision Machining (UPM) has been s...

Ultra-precision CNC machine tools play a significant role in the machining of precision dies and molds, optics, consumer electronics, etc., Due to the nature of ultra-precision machining, a subtle change in process condition, machine anomalies, etc. may significantly influence the machining outcome. Hence, continuous monitoring of the equipment’s o...

Residual stresses play an important role in determining the quality of a machined surface during ultra-precision machining (UPM) of ceramics by initiating cracks at premature loads. In this study, the anisotropy in residual stresses resulting from UPM of two crystallographic planes of sapphire is investigated using micro-Raman spectroscopy. An anal...

Machining of steel-based alloy (STAVAX) and tungsten carbide (WC) is very challenging due to their superior hardness. Severe wear in the machining of the die materials is the dominant problem. Texturing on the rake face of the tool and ultrasonic elliptical vibration cutting (UEVC) may resolve this issue and could prolong tool life. The patterns on...

In machining of a microstructure on a free form surface, a five-axis ultra-precision machine tool has a great advantage in its flexibility and efficiency compared to a conventional machine tool. However, rotary axes in the five-axis machine tools are sensitive to geometric errors due to their complicated structures. Therefore, the geometric errors...

In article number 2100040, Youngho Shin, Sangkee Min, and co‐workers present core–multishell cathode materials with longer cycle life, improved rate performance, enhanced thermal stability, and low impedance growth. The mechanical properties of these core–multishell cathode materials are statistically investigated by picoindentation.

Ni‐rich cathode materials provide high energy density, but their structural and surface instability limits their cyclability and thermal stability. As one of the approaches to mitigate this problem, cathode materials comprising Ni‐rich high‐capacity core wrapped in Mn‐rich multiple shells are produced successfully. In contrast to the conventional b...

The feasibility of using deep learning techniques in industrial cold forging for fault detection was investigated. In this work, vibration data were collected from an industrial setting to detect machine conditions resulting in defective products (faults). After collecting data from several commonly encountered faults, a Convolutional Neural Networ...

Machining of mold steel like STAVAX is still challenging due to significant tool wear. The ultrasonic elliptical vibration cutting (UEVC) that enables dramatic reduction of cutting force is considered as a potential solution. Tool-texturing on the rake face to reduce the friction coefficient between chips and the tool can be another solution as wel...

Though superior multifunctional performances of sapphire, heavy surface/subsurface damage during the process limit applications of the material. Many efforts have been made to improve the machinability of the material, by utilizing the ductile-regime cutting. Here, in addition to the efforts on control of material behavior, machining strategies con...

In machining of a microstructure on a free form surface, a five-axis ultra-precision machine tool has a great advantage in its flexibility and efficiency compared to a conventional machine tool. However, rotary axes in the five-axis machine tool are sensitive to position errors due to low rigidity. In addition, micro-tools, which are utilized in mi...

In this paper, the modified slip/fracture activation model has been used in order to understand the mechanism of ductile-brittle transition on the R-plane of sapphire during ultra-precision machining by reflecting direction of resultant force. Anisotropic characteristics of crack morphology and ductility of machining depending on cutting direction...

Micro grinding with a poly crystalline diamond (PCD) tool is one of the promising approaches for fabricating a micro mold on difficult-to-cut materials. As the process can also achieve good surface integrity without additional finishing processes, it could shorten total processing time and reduce total energy and resource impact. Modeling of micro...

This paper presents a method to identify the position independent geometric errors of rotary axis and tool setting simultaneously using on-machine measurement. Reducing geometric errors of an ultra-precision five-axis machine tool is a key to improve machining accuracy. Five-axis machines are more complicated and less rigid than three axis machine...

Detecting machine mode can allow smarter process monitoring systems and more accurate fault prediction without external information. A remote machine monitoring system was installed on a cold heading machine in the factory of an automotive fastener manufacturing company. The process monitoring system was non-intrusive and was designed to measure vi...

Texturing on the rake face of the tool without the metal working fluid is a potential method to reduce the friction coefficient in ultra-precision machining of tungsten carbide (WC) with a diamond tool. Low friction coefficient of the patterned tool would generate less heat in the tool-work interface and improve the tool life. This paper studies th...

Improving capacity retention during cycling and the thermal–abuse tolerance of layered high–nickel cathode material, LiNi0.8Mn0.1Co0.1O2 (NMC811), is a significant challenge. A series of core–shell structured cathode materials with the overall composition of LiNi0.8Mn0.1Co0.1O2 was prepared via a coprecipitation method in which the nickel–rich comp...

Manufacturability of advanced ceramics has been a challenging issue mainly because of their brittle behaviors and high hardness. One approach to solving this issue is enabling ductile regime cutting, which can also be used to enhance the quality of the surface and accuracy of the final product. There have been many studies investigating how to cont...

Numerous efforts have been made to assess and model the power consumption of machining process, which has led to many standards for energy labeling of machine tools. However, more investigation is required to improve the applicability of these standards because the energy patterns of machines vary widely with respect to the machine type, size, and...

Processing ceramics like sapphire is challenging due to the brittle response exhibited during machining which poses a limitation on maximum material removal rate and throughput of the machining process. Due to this limitation, material has to be removed in small increments in order to create the required form and shape. This study investigates the...

Single-crystal sapphire is utilized as a high-performance engineering material, especially in extreme and harsh environments. However, due to its extreme hardness and brittleness, the machinability of sapphire is still a challenge. By means of nanoindentation and plunge-cut experiments, the anisotropic brittle-ductile transition of the prismatic M-...

There has been a growing trend in industry towards the development of integrated manufacturing centers that combine several manufacturing processes, such as the mill-turn center. As additive manufacturing becomes a more widely adopted technology, combining additive with subtractive manufacturing in one machine is a logical evolution to provide the...

A machine-based power consumption model was developed to cope with a wide variety of machine tool configurations. By focusing on machine components, power consumption can be measured readily and reconfigured per individual component. This research focused mainly on feed drive units of machine tools, and particularly the power characteristics of rot...

The ductile–brittle transition was investigated based on material crystallography and stress intensity factor on the four distinctive planes of sapphire. Cutting forces were analyzed to explain the anisotropic transition characteristics. The projected stress on the objective plane at the transition point was estimated from the critical stress inten...

In this paper, we present a review of machine health managements for the smart factory. As the Industry 4.0 leads current factory automation and intelligent machines, the machine health management for diagnostic and prognostic purposes are essential, and their importance is getting more significant for the realization of the smart factory in the In...

Rising and fluctuating energy prices, an increasing scarcity of fossil fuels and a high demand of electrical energy make industrial companies search for environmental friendly and sustainable solutions. Companies are interested to use renewable energies at their production site or to support the increase of renewable energy systems by adapting thei...

In this study, crystal orientation dependent machinability was investigated in machining of 8 mol% monocrystalline cubic yttria stabilized zirconia (YSZ). The machinability transition from ductile to brittle cutting regime was observed and investigated. Machining characteristics and crack morphologies showed two-fold symmetry following cubic crysta...

Micro- and nano-structuring have been highlighted over several decades in both science and engineering fields. In addition to continuous efforts in fabrication techniques, investigations in scalable nanomanufacturing have been pursued to achieve reduced feature size, fewer constraints in terms of materials and dimensional complexity, as well as imp...

In this study, plunge-cut tests are conducted on single-crystal sapphire to investigate the brittle and ductile deformation mechanisms from the viewpoint of crystal anisotropy. The anisotropic deformation behaviour of the machined sapphire substrate manifests itself in the critical depth of cut and the diverse crack morphologies. Based on a resolve...

Sapphire has received increasing attention as an engineering material even though its machinability is still an issue. In this study, the influence of the milling process parameters on the surface quality of single-crystal sapphire is investigated. Due to the hardness and brittleness of the sapphire substrate, crack initiation becomes the main conc...

The objective of this work is to compare the energy consumption associated with the creation of a small volume of steel by wire-based additive-subtractive manufacturing and powder-based additive-subtractive manufacturing. Additive manufacturing is a growing area of research, encompassing many different processes aimed at producing final products. H...

The objective of this work is to compare the energy consumption associated with the creation of a small volume of steel by wire-based additive-subtractive manufacturing and powder-based additive-subtractive manufacturing. Additive manufacturing is a growing area of research, encompassing many different processes aimed at producing final products. H...

Manufacturing paradigms have historically been shaped by social, economic, and technological aspect, including limitations and needs. Design for manufacturing (DFM) has been the main paradigm for last three decades since design is defined by the limitations of available manufacturing processes. Since reducing the time required for the development o...

This study presents a simple methodology for capturing power consumption by acceleration and deceleration of feed drive on a vertical three-axis milling machine only using a High Speed Power Meter (HSPM). Because of configurations of axes and inertia, not only feed rate but also acceleration power consumption varies in each axis. Acceleration of fe...

Various methods have been developed to describe the energy consumption of machine tools; however, it remains challenging to accommodate the wide variety of machine tools that exist using a single model. In this paper we propose a method to model the energy consumption of machine tools by decoupling the energy of the components of the machine tool f...

In ultra-precision machining including micro milling, a contact point between tool edge and workpiece needs to be set accurately to suppress the machining error. Conventionally, it is detected by using external sensors and devices such as acoustic emission sensors, CCD cameras, and so on. However, detection by using external sensors and devices dep...

A systematic method to assess energy consumption of machine tools for comparable analysis of data and to accurately evaluate the energy efficiency of various machine tools is necessary with increasing interests in green manufacturing. This paper proposes a novel and coherent methodology by presenting a detailed description of different test procedu...

Precise tool length measurement and work coordinate setup have been challenging tasks in ultra-precision machining. An acoustic emission (AE) sensor can be used to do both tasks at the same time based on AE generated on contact. First, a parametric study was conducted to identify the relationship between damage on the workpiece and key parameters....

A new coolant for micro cutting of ferrous materials using a diamond tool was proposed. The effects of the new coolant (ion-shot coolant) which consists of ionized coolant and carbon particles on two steel materials, a high carbon chromium steel and a pre-hardened mold steel were investigated. Also mechanism of the ion-shot cutting was discussed by...

A special coolant system called `Ion-shot coolant system' which consists of an electrolytic liquid and a nano carbon additive was developed. A series of experimental studies had been conducted to understand the effects of the coolant in micro cutting of two steel materials with different carbon content, a high carbon chromium steel (SUJ-2) and a pr...

One of the major concerns in deburring technology is centered on how to predict the size and shape of burrs to insure uniform removal and, if this is possible, how to design the process or product in advance to minimize or control the burr size. This paper reviews some of the research done over the past several years on this important topic. The pa...

Increasing demands on function and performance call for burr-free workpiece edges after machining. Since deburring is a costly and non-value-added operation, the understanding and control of burr formation is a research topic with high relevance to industrial applications. Following a review of burr classifications along with the corresponding meas...

A special coolant system called 'Ion-shot coolant system' which consists of an electrolytic liquid and a nano carbon additive was developed. A series of experimental studies had been conducted to understand the effects of the coolant in micro cutting of two steel materials with different carbon content, a high carbon chromium steel (SUJ-2) and a pr...

The range of surface roughnesses, and particularly the minimum roughnesses, achievable mainly with cemented carbide but also with single crystal diamond round nosed turning and facing inserts, has been experimentally studied, machining aluminium on engineering and precision lathes. Insert edge sharpness and roughness measurements and characteristic...

The surface quality and the dimensional accuracy are important criteria for micro-mold production, specially for micro-fluidic devices. Important cutting parameters that affect the quality of vertical side walls created by the peripheral cutting edge in micro-end-milling operations were identified. Surface roughness and form error were used to defi...

The range of and particularly the minimum surface roughnesses achievable mainly with cemented carbide but also with single crystal diamond round nosed turning and facing inserts has been experimentally studied, machining aluminium and steel on engineering and precision lathes. Characteristic variations of machined surface profile with feed rate as...

A special coolant system called 'ion-shot coolant system' was developed for machining of the ferrous material with a diamond tool. It consists of ELID (Electrolytic In-process Dressing) liquid and nanometer size carbon particles. A series of micromachining experiments were conducted on high carbon chromium steel workpieces with single diamond tools...

An understanding of burr formation and edge defects is critical to efficient production of machined features in precision components. Analytical models of burr formation and edge effects including the tool/workpiece interaction and material influences are necessary for building databases describing cutting conditions for optimal edge quality, and d...

This paper reviews some of the main drivers, developments and future requirements in the field of micromanufacturing as related to the machining process from the perspective of the recent research and development literature. For the purposes of this paper micromachining includes creation of precise two and three dimensional workpieces with dimensio...

For practical application of micromechanical machining, four levels of process realization are required; fundamental understanding of process physics, development of microplanning (processing parameter optimization), macroplanning (tool path planning), and design optimization. This study surveyed the influence of localized variation in the microstr...

Micromachining applications have received increased emphasis in recent years with the advent of new precision manufacturing applications which have stringent requirements for surface and edge finish. One of the main concerns in micromachining is burr formation which can incur high production costs due to time-consuming deburring operations. Althoug...

Micromachining is a preferable fabrication method for tooling such as a micromold, rather than as a direct method of mass production. For tool fabrication, the precision of machining should receive much more attention than aspects such as productivity, efficiency, and economics. The accuracy of microfeatures on the microtooling for scalable manufac...

The investigation using high vacuum cutting apparatus indicated the ester and oxygen were likely to enhance mutually their adsorption activities. The experimental facts obtained by normal atmosphere cutting apparatus demonstrated that a synthetic ester for MQL machining provided the better cutting performance in the order of higher oxygen concentra...

The surface and edge quality of single-crystal and polycrystalline copper workpieces has been observed to vary significantly as a function of crystallographic orientation. On the precision scale, the chip formation process is influenced by the microstructure of the material, such as grain boundaries and grain orientation in polycrystalline material...

Despite the fact that minimal quantity lubrication (MQL) machining produces almost similar cutting performance to conventional flood supply machining while using much less metal working fluid (MWF), it has not been fully utilized in industry due to lack of understanding of the fundamental process physics. To take full advantage of MQL machining and...

With increasing demands in manufacturing for smaller and more precise features, the advent of micromechanical machining processes, such as microdrilling and micromilling to create features at the meso (sub-mm) to micro (micron) scale are of increasing importance. However, at the length scales found in micromechanical machining, localized variation...

The surface and edge quality of single crystal and polycrystalline copper workpiece has been observed to vary significantly as a function of crystallographic orientation. At the precision scale, the chip formation process is influenced by the microstructure of the material, such as grain boundaries and grain orientation in polycrystalline materials...

Near-dry machining (NDM) is a technology with many ecological and economic benefits that uses very small amounts of metal working fluid (MWF). In order to increase the applications of this technology, the tribological mechanism during this process needs to be better understood. To accomplish this, two experimental set-ups were configured. The first...

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

The influence of an exit surface angle on drilling burr formation was analyzed. The experimental research found that a burr forms on only a certain portion of a hole when an exit surface is not perpendicular to a drill path. An effective interaction angle was newly defined and the concept of degree of plastic deformation was introduced in order to...

Burr problems can be approached at various stages from design to final processing. Four levels of burr minimization strategies are proposed. A case study is included to illustrate the application of these strategies. One of the approaches uses the Drilling Burr Expert System© developed at UC Berkeley in order to find optimal cutting conditions for...

This study is focused on thrust force analysis of the drilling burr formation. A finite element model (FEM) for drilling burr This study is focused on thrust force analysis of the drilling burr formation. A finite element model (FEM) for drilling burr formation was proposed with a stainless steel (AISI 304L) workpiece and a conventional twist drill...

In order to advance understanding of the burr formation process, a series of finite element models are introduced. First, a finite element model of the burr formation of two-dimensional orthogonal cutting is introduced and validated with experimental observations. A detailed and thorough examination of the drilling burr forming process is undertake...

A control chart for drilling burr formation for low alloy steel, AISI 4118, was developed. A drilling burr control chart, based on experimental data, is a tool for the prediction and control of drilling burrs. High-speed steel split-point twist drills with different diameters were used for the tests. Burr classification was carried out based on the...

Control charts for drilling burr formation for stainless, AISI 304L, and low alloy steel, AISI 4118, were developed. Split point twist drills are used for the experiments of this work. A Drilling Burr Control Chart, based on experimental data, is a tool for prediction and control of drilling burrs. Burr classification was carried out based on the g...

Burr research is undeniably highly complex. In order to advance understanding of the process involved several techniques are being implemented. First a detailed and thorough examination of the burr forming process is undertaken. The technique is difficult, intricate and time consuming, but delivers a large amount of vital physical data. This inform...

Burr research is undeniably highly complex. In order to advance understanding of the process involved several techniques are being implemented. First a detailed and thorough examination of the burr forming process is undertaken. The technique is difficult, intricate and time consuming, but delivers a large amount of vital physical data. This inform...

New demands are being placed on monitoring systems in the manufacturing environment because of recent developments and trends in machining technology and machine tool design. In-process sensors are used to generate control signals to improve both the control and productivity of manufacturing systems. For example, acoustic emission sensors are used...

A 3-dimensional finite element model of drilling burr formation was proposed. A conventional twist drill was used and assumed to be a rigid body. Stainless steel (AISI 304L) was modeled for the workpiece material. An incremental plasticity model with associated flow rule and isotropic hardening rule was used to describe a plastic behavior of the wo...

To overcome difficulty in machining of a ferrous material with a diamond tool, a new coolant system named 'ion-shot coolant system' was developed utilizing ELID (Electrolytic In-process Dressing) electrolytic coolant and nanometer size carbon particles. A series of experiments conducted to show effects of the ion-shot coolant system on high carbon...

Thesis (Ph. D. in Engineering-Mechanical Engineering)--University of California, Berkeley, Fall 2001. Includes bibliographical references (leaves 136-145).