• 한국공작기계학회논문집
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• 제13권6호
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• pp.81-86
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• 2004

Generally, automotive cylinder head is manufactured by FCD45 material that is hard to cutting materials, and it needs the accurate machining tool fir higher output of engine. This paper is concerned with a study on TiN coated 6 edges reamer for improving machining accuracy of cylinder head guide pin. The reamer shape is changed from 4 edges to 6 edges for the improvement of machining accuracy. Also, TiN coating is applied to the improvement of surface roughness of cylinder head guide pin and tool life of 6 edges reamer. It is noted that 6 edges reamer are effective in controlling the dimensional accuracy and surface roughness as well as increasing tool life.

• 한국정밀공학회지
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• 제28권8호
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• pp.886-893
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• 2011

To increase the reliability and positional accuracy of a machine tool, a novel capacitive displacement sensor having a cylindrical shape is presented to measure the axial displacement of a machine tool spindle. Characteristics of the sensor were analyzed by numerical simulation. The sensor was built into a specific machine tool spindle and its performance was experimentally investigated. The accuracy of a thermal error compensation system of a machine tool can be enhanced greatly using proposed sensor.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.170-174
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• 1990

The information with regard to the working range of lathe, cutting tool, cutting condition is managed as Database system for turning operation as one part of CAM system. Data with regard to the working range of lathe, cutting tool, cutting condition are stored by the DBMS(Data Base Management System) and can be added, modified, deleted and retrieved for realtime usages. Data stored in Database system are searched to select the most proper cutting tool and cutting condition with the input data fed from the design stage. Codes in regards to tool shape are displayed on graphic mode for easy selection for user and thus presents a good decision support for tool selection. The system developed in this work is operated by the pull down menu on the IBM PC/AT personal computer, or compatible series.

• Geomechanics and Engineering
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• 제20권5호
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• pp.421-432
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• 2020

Cutting of rocks is very common encountered in tunneling and mining during underground excavations. A deep understanding of rock-tool interaction can promote industrial applications significantly. In this paper, a distinct element method based approach, PFC^3D, is adopted to simulate the rock cutting under different operation conditions (cutting velocity, depth of cut and rake angle) and with various tool geometries (tip angle, tip wear and tip shape). Simulation results showed that the cutting force and accumulated number of cracks increase with increasing cutting velocity, cut depth, tip angle and pick abrasion. The number of cracks and cutting force decrease with increasing negative rake angle and increase with increasing positive rake angle. The numerical approach can offer a better insight into the rock-tool interaction during the rock cutting process. The proposed numerical method can be used to assess the rock cuttability, to estimate the cutting performance, and to design the cutter head.

• 대한기계학회논문집
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• 제18권1호
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• pp.53-64
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• 1994

Rouge cutting process takes the major portion of machining operation using NC milling machine. Especially, most of the machining time is spent in this process when molds are machined. Therefore, an efficient algorithm for generating the tool path for rough cutting is suggested in this paper. The first step of the procedure is getting the volume to be machined by applying the Boolean operation on the finished model and the workpiece which have been modeling system. Basic principle of determining machining procedure is that a large tool should be used at the portion of the simple shape while a small tool should be used at the complex portion. This principle is realized by representing the volume to be machined by an octree, which is basically a set of hexahedrons, and matching the proper tools with the given octants. When the tools are matched with the octants, the tool path can be derived at the same time.

• 한국생산제조학회지
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• 제18권6호
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• pp.636-641
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• 2009

Recently, expansion of micro-technology parts requires micro-precision machining technology. Micro-groove machining is important to fabricate micro-grating lens and many micro-parts such as microscope lens, fluidic graphite channel etc. Conventional groove fabrication methods such as etching and lithography have some problems in efficiency and surface integrity. But, mechanical micromachining methods using single crystal diamond tools can reduce these problems in chemical process. For this reason, microfabrication methods are expected to be very efficient, and widely studied. This study deals with machinability in micro-precision V-grooves machining of nickel plated layer using non-rotational single crystal diamond tool and 3-axis micro stages. Micro V-groove shape, chip formation and tool wear were investigated for the analysis of machinability of Ni plated layer.

• 한국공작기계학회논문집
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• 제12권2호
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• pp.9-16
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• 2003

A strategy of the optimal shape design with FEA(Finite Element Analysis) for 2-D structure is proposed by comparing subproblem approximation method with first order approximation method. A cantilever beam with two different loading conditions, a concentrated load and an evenly distribute load, and truss structure with a concentrated loading condition are implemented to optimize the shape. It gives a good design strategy on the optimal truss structure as well as the optimal cantilever beam shape. It is found that the convergence is quickly finished with the iteration number below ten. Optimized shapes of cantilever beam and truss structure are shown with stress contour plot by the results of the subproblem approximation method and the first order approximation methd.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.166-171
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• 2004

In this study, shape optimization of micro-static mixer with a cantilever beam was accomplished for mixing the mixing efficiency by using successive response surface approximations. Variables were chosen as the length of cantilever beam and the angle between horizontal and the cantilever beam. Sequential approximate optimization method was used to deal with both highly nonlinear and non-smooth characteristics of flow field in a micro-static mixer. Shape optimization problem of a micro-static mixer can be divided into a series of simple subproblems. Approximation to solve the subproblems was performed by response surface approximation, which does not require the sensitivity analysis. To verify the reliability of approximated objective function and the accuracy of it, ANOVA analysis and variables selection method were implemented, respectively. It was verified that successive response surface approximation worked very well and the mixing efficiency was improved very much comparing with the initial shape of a micro-static mixer.

• 소성∙가공
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• 제6권5호
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• pp.400-407
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• 1997

Geometric mapping technique has been used to find the shape of initial blank for sheet forming. The method was chosen because of its simplicity and numerical efficiency. Error in blank shape were measured along deformation path by FE analysis of forming. Blank shape was modified by volume additionaddition/Subtractiontraction method with taking with taking into account of deformation path. Modified blank shape shows an acceptable result, showing the current method can be an useful tool for predicting blank shape in the practical application. More test will be done to verify the validity of the method.

• 한국기계가공학회지
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• 제15권5호
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• pp.137-144
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• 2016

This paper aims to ensure describe the a spring-back prevention technique for improving shape fixability by using an ultra-high strength steel sheet with 980 MPa to develop a lightweight seat rail parts. Ultra-high strength steel gives a potential for considerable weight reduction and a cost-effective way to produce energy efficient vehicles. The influence of a spring-back of seat rail parts on the shape fixability in forming processes was investigated to be solved by an adjustment of the appropriate tool design and process parameters. The computed results for improving shape fixability were in good agreement with the experimental results.