• Journal of the Korean Society for Precision Engineering
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• v.18 no.4
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• pp.182-189
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• 2001

TiCN based submicron cermet and similar ISO grad of the conventional cermets with TiCN of different particle size were produced by PM process, and their microstructure, mechanical properties and cutting performance were compared. The microstructure of submicron cermet was more homogeneous and showed much finer microstructure, resulting in better hardness and fracture toughness. The submicron cermet tools achieved excellent cutting performance such as wear resistance and toughness in comparison with two grades of the conventional cermets in millimg test. The relationship between microstrucure, mechanical properties and cutting performance of these cermet tools was discussed. The submicron cermet tools revealed for their potential to wide application range and interrupt cutting because of their superior wear resistance and toughness combinations.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.880-884
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• 1995

Manufacturing environment is getting characterized by unstable market demand,short product life cycle and timebased competition. For adapting this environment,machine tools have to be further versatile functionally in order to reduce part's set-up time. Unlike existing manufacturing systems mainly to focus on part flow, it is important to control tool flow using fast tool change device and tool delivery device in parallel machines consisting of versatile machine tools, because complete operations on a part can be performed on one machine tool in a single machine set-up. In this paper, under dynamic tool allocation strategy to share tools among machine tools, we propose a real-time tool allocation and operation esequence model with an objective of minimizing flow time using autonomy and negotiation of agents in parallel machines

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.858-861
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• 2001

As the application fields of micro parts that are micro endo-scope, PDA, and tele-communication had been extended, there are required the micro machine tools and MEMS in order to machining for those parts. In order to machining of the micro parts, the micro machining center is very effective. The micro machining center had some advantages that are lower cost, higher accuracy, and lower required powers than existing machine tools for machining of micro parts. In this study, in order to analyze the machining characteristics and its application possibility of the developing micro machining center with 60,000rpm rotations, 0.1$\mu\textrm{m}$ resolutions, and 80 50 50mm sliding unit, the machining experiment had been executed. In this experimental machining, 0.1~ 0.5mm endmills are used to machining the micro cap and tele-communication's parts. In the future, experimental results will be adapted to the micro-machining center.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.133-136
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• 2003

In these days, the reliability analysis and prediction are applied for many industrial products and many products require guaranteeing the quality and efficiency of their products. In this study reliability prediction for core units of machine tools has been performed in order to improve and analyze its reliability. ATC(Automatic Tool Changer) and interface Card of PC-NC that are core component of the machine tools were chosen as the target of the reliability prediction. A reliability analysis tool was used to obtain the reliability data(failure rate database) for reliability prediction. It is expected that the results of reliability prediction be applied to improve and evaluate its reliability. Failure rate, MTBF (Mean Time Between Failure) and reliability for core units of machine tools were evaluated and analyzed in this study.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.1
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• pp.104-111
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• 1995

The needs of ultraprecision machine tools, which manufacture and machine the high precision parts used in computers, semiconductors and othe rprecise machines, have been increased recentrly. So it is important to design the driving parts of the ultraprecision machine tools which affect significantly on the performance of them. In this paper, the dynamic analyses on the belt-drive system were studied. The correlational equations between the acoustic natural frequency and the tension of belt were derived by experiments. The dynamic delections while the dynamic loads on the motor system changed were analyzed by the finite element analysis. The nonlinear characteristics of the bearings on the dynamic performance was studied and the belt connecting the motor to the spindle of a machine tool was modeled by the truss element and the beam element.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.8
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• pp.869-877
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• 2011

In order to manufacture precision parts which are used for IT and BT Industry by machining, users need higher speed & precision machining center. So, for development of this kind of machine, we designed gantry type machining center which is piling of 3 axes on one moving body and the 2-axis rotary table is fixed on the base. It is applied linear motor that is instead of ball-screw and servo-motor combination and 50,000 rpm high-speed spindle. Composite material structure called mineral casting or resin concrete is applied also. This paper presents design technology and evaluated results of high speed and precision machining center.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.323-328
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• 1992

The vibrations of the main spindles of the M/C tools is the most important in the con- sideration of the dynamic performance of the M/C tools. In order to analyze and predict the dynamic behaviour of the machine tool structure it is necessary to have the mathematical model of the system. The system identification is the procedure to provide us with the mathematical model of the system of which we want to know the dynamic characteristics. This study illustrates a procedure of the system identification of the structure of the M/C tools to predict the dynamic behaviour of the machine and further to have the basis for the design of M/C tools.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.114-121
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• 1996

This paper presents an useful technique for assessing the volumetric errors in multi-axis machine tools using the kinematic double ball bar. This system has been developed based on the volumetric error map which describes the 3 dimensional errors of machine tools. The developed system inputs the measured radial data of 3 different planes, respectively XY,YZ,ZX, analysing the volumetric errors such as positional. straightness, angle, and squareness errors, etc. The developed system has been tested in a practical machine tool, and showed high potential for the error assessment of multi-axis machine tools.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.43-52
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• 1999

In this study, the vibration damping characteristics of the powered hand tools transmitted in hand-arm system were examined and compared. The types of powered tools for the experiment are general typed drill, impact drill, grinder, and wire brush. To analyze the characteristics of vibration damping, the magnitude of acceleration of vibration on X, Y, and Z direction at tool, hand, wrist, and the joint between forearm and upper arm were measured respectively. The results indicated that impact drill generated the highest value of acceleration of vibration among the four types of tools used in the experiments. The highest value of the amount of acceleration of vibration was found in the direction of Y. And the amount of acceleration of vibration was significantly affected by the type of tool, type of work, and pushing forces. As become the more distant from the tool, the smaller the amount of acceleration of vibration. Also, the bigger the pushing force at the tool, the higher the acceleration of vibration.

• Journal of Construction Engineering and Project Management
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• v.8 no.1
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• pp.22-30
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• 2018

Achieving sustainability targets on construction projects has increasingly become one of the prime strategies for construction organizations. To provide more detailed guidance on sustainability implementation on projects, Construction Industry Institute (CII) Research Team (RT) 304 developed a catalog of the Construction Phase Sustainability Actions (CPSAs). The primary objective of this paper was the development of two support tools, the CPSA Screening Tool and the CPSA Implementation Index, that could be used to enable efficient application of CPSAs, support sustainability-related decisions, and measure CPSA implementation and performance. The authors developed the tools in four stages: conceptual, detailed planning, tool programming, and testing. The tools were then demonstrated on a capital project to confirm their efficacy and applicability. This paper presents the background, inputs and outputs, and the algorithms of each tool. The CPSA Screening Tool can prioritize the CPSAs most relevant to a project; the CPSA Implementation Index enables continuous monitoring of implementation levels.