• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1351-1354
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• 2005

분산응용을 개발하는데 효율적인 환경을 제공해주는 분산 객체그룹 프레임워크(Distributed Object Group Framework)를 이용한 분산 프로그램 개발 Tool-Kit을 구축하였다. 본 Tool-Kit은 분산응용 개발자들에게 DOGF의 기능을 쉽게 이용할 수 있도록 지원하기 위해 객체그룹 운영자 GUI, 서버 프로그램 개발자 GUI, 클라이언트 프로그램 개발자 GUI등 3가지 GUI로 구축하였다. 분산응용의 개발 시, 서버 프로그램 개발자는 서버 객체들 구현한 후 프레임워크에 등록 및 클라이언트에 대한 접근권한을 부여하고, 클라이언트 프로그램 개발자는 자신에게 접근권한이 부여된 이들 객체 또는 객체그룹을 검색하여 클라이언트 프로그램을 작성할 수 있도록 지원한다. 본 논문에서는 분산응용 개발 시 이용되는 Tool-Kit과 DOGF의 상호동작을 정의하고, 분산 프로그램개발 Tool-Kit을 구축하고, 간단한 분산응용을 이용해 Tool-Kit의 수행성을 보인다.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.5
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• pp.431-439
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• 2014

Recently, a demand for precision 5-axis machine tools is significantly increasing, and the maintenance of machine tool accuracy becomes more important. it is very difficult to evaluate to accuracy of 5-axis M/C in the production site since it needs expensive measuring equipment and skilled engineer. On the other hand, evaluation items of 5-axis M/C are not systematically organized in the existing KS and ISO standards. In this study, the evaluation items for 5-axis M/C were derived systematically and a test workpiece was developed to evaluate the machine tool accuracy more easily. The error sources of machine tool can be estimated by machining and measuring of the test workpiece. The correlation between the machine tool accuracy and the accuracy of machined test workpiece was analyzed. As a result, the accuracy of machined test workpiece represented the accuracy of machine tool and the error sources very effectively.

• Industrial Engineering and Management Systems
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• v.9 no.3
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• pp.242-250
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• 2010

For economical and environmental reasons, the aim of this research is hence to monitor the cutting conditions with the dry cutting, the wet cutting, and the mist cutting to obtain the proper cutting condition for the plain carbon steel with the ball end milling based on the consideration of the surface roughness of the machined parts, the life of the cutting tools, the use of the cutting fluids, the density of the particles of cutting fluids dispersed in the working area, and the cost of cutting. The experimentally obtained results of the relation between tool wear and surface roughness, the relation between tool wear and cutting force, and the relation between cutting force and surface roughness are correspondent with the same trend. The phenomena of surface roughness and tool wear can be explained by the in-process cutting forces. The models of the tool wear with the cutting conditions and the cutting times are proposed to estimate the tool cost for the different cooling strategies based on the experimental data using the multiple regression technique. The cutting cost is calculated from the costs of cutting tool and cutting fluid. The mist cutting gives the lowest cutting cost as compared to others. The experimentally obtained proper cutting condition is determined based on the experimental results referring to the criteria.

• IE interfaces
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• v.19 no.4
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• pp.316-323
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• 2006

In this study, based on Weibull proportional age reduction model and age replacement policy, we analyze economic life of cutting tool which allows re-grinding. Re-grinding task, usually for high-priced machining tools(e.g., broaching tool), is a kind of preventive maintenance activities to extend tool life at the completion of a lot production. The numerical results are also presented. Among the parameters of Weibull proportional age reduction model, the re-grinding effect parameter and Weibull shape parameter have a strong effect on economic tool life, and in the cost parameters, shortage cost is most sensitive. With further study on the parameter estimation of tool life process and cost function, this study can be expected to give more practical contribution to management of general machining tools.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.35-42
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• 2002

Verification of tool collision Is an important issue in die and mold machining. In this paper three functions of verification for 3-axis milling machining are schematically explained. Operators of geometric models are explained at first, which will be used in the functions of verification. The first verification function is getting a collision-free region when a tool assembly and a part surface model are given. The second function estimates the shortest length of cutter shank with that the tool cuts all of a region without collision The last one is cutting simulation considering all parts of tool assembly as well as cutter blade. Proposed approaches can be easily implemented by using several basic operators of geometric model. An example to calculate collision-free region is presented also.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.3
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• pp.56-61
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• 2002

CuFe$_2$O$_4$ ferrite was machined with cermet tools to clarify the machinability. The tool wear became the smallest at the cutting speed of 90m/min with the depth of cut of 0.2mm. The surface roughness became larger with increasing the cutting speed and the chamfer angle of tool. The tool with the chamfer angle of 15° showed the smallest wear. The surface roughness increased almost proportionally with the increase of chip size. The tool wear reduced with increasing feed in the depth of cut not more than 0.2mm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.315-318
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• 1997

In terms of productivity, the speed of machining process has been increasing in most of engineering part. But the tapping process does not reach at enough level compared with other machining processes because of its complicate cutting mechanism. In the high speed tapping process, the one of important elements is tool monitoring system to prevent tool breakage. This paper describes tool monitoring system by acoustic emission(AE) in the tapping process. We used 2 types of AE sensors in this test. The one is commercial sensor which is used in other machining monitoring system like polishing and the other is a self-fabricated sensor for this test. In this test we purpose to find out the frequency of AE signal in tapping process and verify the possibility of applying AE sensor in in-process tapping monitoring system. Also grasp of characteristic of tapping process by AE signal is handled.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.311-314
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• 1995

This paper presents a method for measuring tool wear parameters based on two dimensional image information. The tool wear images were obtained from an ITV camera with magnifying and lighting devices, and were analyzed using image processing techniques such as thresholding, noise filtering and boundary tracing. Thresholding was used to transform the captured gray scale image into a binary image for rapid sequential image processing. The threshold level was determined using a novel technique in which the brightness histograms of two concentric windows containing the tool wear image were compared. The use of noise filtering and boundary tracing to reduce the measuring errors was explored. Performance tests of the measurement precision and processing speed revealed that the direct method was highly effective in intermittent tool wear monitoring.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.769-772
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• 2005

그동안 우리는 분산응용을 구성하는 자원들을 하나의 논리적인 그룹으로 관리하기 위한 연구를 수행하여 분산객체그룹 프레임워크(Distributed Object Group Framework, DOGF)를 구축하였다. 또한 DOGF 기반에서 분산응용의 복잡한 개발절차를 최소화하고, 이전에 개발된 분산자원들의 재사용성을 효율적으로 제고할 수 있는 분산프로그램 개발도구인 DPD-Tool(Distributed Programming Developing Tool)을 개발하였다. 본 논문에서는 우리가 개발한 GUI 지원 DPD-Tool을 이용한 분산응용의 개발 편리성과 DOGF가 지원하는 그룹관리 분산서비스의 수행성을 검증한다. 이를 위해 GUI 기반에서 분산응용의 예를 들어 서버와 클라이언트 측의 개발절차를 제시하며, 이로부터 DPD-Tool이 DOGF의 지원 서비스를 통하여 그룹화 분산응용 내 중복자원들을 효율적으로 이용하는지 그 수행결과를 확인한다.

• Proceedings of the Korea Society for Simulation Conference
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• 1998.10a
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• pp.204-208
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• 1998

The fundamental issues to evaluate machine tool's performance through simulation pertain to the physical models of the machine tool itself and of process while the practical problems are related to the development of the modular software structure. It allows the composition of arbitrary machine/process models along with the development of programs to evaluate each state of machining process. Surface roughness is one of the fundamental factors to evaluate machining process and performance of machine tool, but it is not easy to evaluate surface roughness due to its tribological complexity. This paper presents an algorithm to calculate surface roughness considering cutting geometry, cutting parameters, and contact dynamics of cutting between tool and workpiece as well as tool wear in turning process. The designed virtual machining system can be used to evaluate the surface integrity of a turned surface during the design and process planning phase for the design for manufacturability analysis of the concurrent engineering.