• Journal of the Korean Society for Precision Engineering
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• v.32 no.8
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• pp.693-698
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• 2015

Recently, the quality of products after the corresponding machining processes were scrutinized in the interest of maintaining a high product-quality standard. The structure and stability of machine tools are important for the prediction of product quality. A structural analysis needs to be carried out to achieve the stable design of machine tools before the initial design stage in the manufacturing process of a precision product. In this study, a structural analysis was carried out using a finite element analysis (FEA) simulation to obtain the design stability of the main parts of a grinding machine. The sizes and locations of both the maximum stress and deformation in consideration of the cutting force of the chuck, tail stock, and bearing of the grinding machine were analyzed. Finally the grinding machine was successfully developed.

• Journal of the Korean Society of Systems Engineering
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• v.12 no.2
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• pp.9-18
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• 2016

Machine switch type control panel is widely used for machine tools in Korea. They, however, have some difficulties in identifying the current operating status of machine tools especially when exposed to cutting oil. And also they have quality problems of operating failures. A new capacitor touch type machine control panel is developed and its reliability is predicted. MIL-HDBK-217F and Teclordia SR-332 are used for its reliability prediction and the prediction results are compared.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.123-128
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• 2005

A novel tri-mode ultraprecision positioning system for machine tools and measuring machine is proposed. The basic coarse mode uses a Twist-roller Friction Drive (abbr. TFD), and controls several tens of millimeters of the machine-table travel with nanometer order of positioning resolution. The fine mode also utilizes the TFD with a fine adjusting mechanism. The resolution of the fine mode is in the range of sub-nanometer. For realizing picometer positioning, the ultra-fine mode is executed by using an active aerostatic guideway. On the bearing surface of this active guideway, several Active Inherent Restrictors (abbr. AIRs) are embedded for controlling the table position. An AIR unit consists of a piezoelectric actuator having a through hole, one end of the hole on the bearing surface acts as an inherent restrictor. Owing to the aerostatic mechanism of the AIR, the deformation of the piezoelectric actuator in the AIR unit causes much reduced table displacement. Such motion reduction is effective for ultraprecision positioning. Current positioning resolution of the ultra-fine mode is 50pm, however the final goal of the positioning resolution is expected to be in the order of picometer.

• Journal of the Korean Society of Safety
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• v.37 no.4
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• pp.1-10
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• 2022

The purposes of this study were to suggest 1) a future direction for Korea's machine tool industry and 2) how to secure the safety and reliability of emerging intelligent or automated machine tooling. The study concludes that, overseas, the machine tool industry is growing again while promoting innovation by converging with ICT. Accordingly, Korea also promotes ICT innovation to advance the machine tool industry, which is at the core of the national economy. As a result, unlike in the past, the frequency of serious injuries like entrapment accidents has recently decreased, while the proportion of collision accidents has increased. In addition, a new type of accident has become possible. Since ICT is network-based, the distinction between work and rest can become ambiguous; there is a risk of hacking, working hours and places are flexible and there are risk factors for diseases like chronic fatigue due to overload of specific personnel. As robots and automation are introduced, there is also a high probability of problems caused by physical and psychological burdens on system operators and resulting fatigue.

• Journal of Mechanical Science and Technology
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• v.17 no.6
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• pp.896-905
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• 2003

A linear motor has many advantages next to conventional feed mechanisms: high transitional speed and acceleration, high control performance, and good positioning accuracy at high speed. Through the omission of a power transfer element, the linear motor shows no wear and no backlash, has a long lifetime, and is easy to assemble. A disadvantage of the linear motor is low efficiency and resultant high-temperature rise in itself and neighboring structures during operation. This paper presents the thermal behavior of the linear motor as a feed mechanism in machine tools. To improve the thermal behavior, an insulation layer is used. By placing the insulation layer between the primary part and the machine table, both the temperature difference and the temperature fluctuation in the machine table due to a varying motor load are reduced.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.528-535
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• 2002

In order to achieve high precision machine tools, the research for performance enhancement of feed drive systems is required. Development of the high speed feed drive system has been a major issue for the past few decades in machine tool industries. The reduction of the tool change time as well as rapid travel time can enhance the productivity. However, the high speed feed drive system generates more heat in nature, which leads thermal expansion that has adverse effects on the accuracy of machined parts. Stick-slip friction has a great influence on the contouring accuracy of CNC machine tools. In this paper table levitation system has been developed for the stick-slip in a feed drive systems. And also, the driving position is set near the center of the main slideway. From the results, it is confirmed that yaw error and straightness can be improved.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.2
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• pp.102-111
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• 2000

Methodology of volumetric error identification and compensation is presented to improve the accuracy of NC machine tools by using a reference artifact and a touch trigger probe. Homogeneous transformation matrix and kinematic chain are used for modeling the geo-metric and thermal errors of a three-axis vertical machining center. The reference artifact is designed and fabricated to identify the model parameters by machine tool metrology. Parameters in the error model are able to be identified and updated by direct measurement of the reference artifact on the machine tool under the actual conditions which include the thermal interactions of error sources. A volumetric error compensation system based on IBM/PC is linked with a FANUC CNC controller to compensate for the identified volumetric error in machining workspace.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.335-340
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• 2004

KS and ISO have proposed several evaluation methods of conventional machine tools. Even though the accuracy of the tools can be evaluated with those methods, there are still no proper evaluation methods of high speed machining. Because it is hard to evaluate characteristics of high speed machining such as decrease of cutting temperature, cutting force, and reduced machining time. Therefore, new evaluation method for high speed machine should be developed. In this paper, several shapes of model have been proposed to evaluate cutting accuracy of high speed machine.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.90-93
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• 2002

In view of reliability assessment, the failure mode analysis by performance tests for machine totals is researched in this study. First, the error analysis with circular movement test data is studied. The various errors and their origins are analyzed by error equations and related parts are investigated. Second, This paper deals with analysis of vibration testing fur machine tools spindle. The various frequency components are classified by FFT and order analysis. The simple measuring devices and error evaluation programs for tests are also developed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.37-41
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• 1993

ball screw is a critical machine component which dictates the precison of a given machine tool. The conventional manufacturing method requires the heat treated ball screw to be ground to its final dimensions. This study looks into the the feasibility of replacing the grinding process with a simpler process, namely threading on NC lathe. The purpose is to reduce the capital investment as well as production time in the manufacture of ball screws. Ceramics and CBN cutting tools are compared with respect to their ability to machine hardened steel. It is shown that CBN tools can be successfully utilized to machine precision ball screws with superior suface qualities.