• 대한기계학회논문집
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• 제18권5호
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• pp.1347-1354
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• 1994

This paper deals with the experimental research, including measurement and analysis and field survey, on the causes of occurring noise defective gear boxes in hoist production plant in order to reduce the fraction of their occurrence. In this reserch following investigations are performed : measurement and gear-boxes, examination of each machining process of production, measurement and analysis of dimensional accuracy of each part, comparative vibration test with exchanging inaccurate parts. From these investigations, it is found that the machining accuracy of pinion gear tooth thickness is the most sensitive factor of noise problem. By maintaining the tooth thickness error within 0.05 mm tolerance in the gear cutting process, the fraction of noise defective gear-boxes are greatly reduced to less than 2%, where the usual rate of it has been 20-50%.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.353-358
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• 2006

A three-dimensional finite element approach to process analysis and design for joining the socket with the ball by a kind of the rotary forging processes is presented in this paper. The rigid-plastic finite element method is employed and its results are used to reduce the number of process design tryouts. The approach is applied to developing a concave piston assembly for a high pressure hydraulic pump. Experiments show that the developed piston assembly satisfies the quality requirement on geometrical tolerance.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.183-188
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• 2002

Co-cured composite materials has its own characteristics, so its thermal expansion is different each other. The selection of tool material for co-cured composite part in high temperature more over $350^{circ}F$ and 50 Psi pressure have to consider part thermal expansion, size, shape, and economic aspect in production line. So it is important choose tooling material in manufacturing composite parts. We called the tool for airplane composite parts as BAJ (Bonding Assembly Jig). Composite parts are cured on the BAJ in autoclave. BAJ have to stable at high temperature over $350^{circ}F$ and 50 Psi pressure, Considering composite parts' dimensional tolerance compare to heat up in autoclave. This paper come from the results of the experiment at the composite parts production line and review other aircraft company's method for tooling This is for the engineer engaged in composite parts manufacturing.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1998년도 금형가공 심포지엄
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• pp.60-66
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• 1998

The horizontal cold chamber pressure die casting produces a variety of net shape, complicate-geometry castings with desired mechanical properties. dimensional tolerance, and surface finish. However, top quality castings can be achieved only when optimal performance of thecold chamber (shot sleeve )and plunger is maintained druing the molten metla injection phase of the process. Unforturately, inreality , shot sleeves deteriorate fast and sometimes fail catastrophically due to incorrect design. These early and unexpected failures of shot sleeves cost die casters money and productiivity. To prevent promature failures of shoe sleeves major faulure mechanisms were investigated. with the aid of analyticla solutions robust design criteria for shot sleeves have been developed. The data directly obtained from failed shot sleeves in the die casting industry for automotive parts, support a strong correlation between design and filures. by applying these design criterial we expected premature faulures of shot sleeves can be avoided in die casting industry.

• 설비공학논문집
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• 제3권1호
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• pp.11-25
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• 1991

The steady, incompressible developing 3-dimensional turblent flow in a square sectioned curved duct has been investigated by using partially-parabolic equation and Finite Analytic Method. The calculation of turbulent flow field is performed using 2-equation K-$\epsilon$ turbulence model, modified wall function, simpler algorithm and numerically generated body fitted coordinates. Iso-mean velocity contours at the various sections are compared with the existing experimental data and elliptic solutions by other authors. In the region of $0^{\circ}<{\theta}<71^{\circ}$, present results agree with the experimental data much better than the elliptic solution for the similar number of grid points. Furthermore, for the same tolerance, the present solution converges four times faster than the elliptic solution.

• 대한기계학회논문집
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• 제18권11호
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• pp.2932-2943
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• 1994

An efficient approach to the automatic construction of effective quadrilateral finite element meshes for two-dimensional analysis is presented. The procedure is composed of, firstly, an initial mesh generation and, secondly, an h-version of adaptive refinement based on error analysis. As for an initial mesh generation scheme, a modified looping algorithm has been employed. For the adaptive refinement process, an error indicator obtained by computing the residual error of the equilibrium equations in the energy norm with a relaxation factor has been employed. Examples of mesh generation and self-adaptive mesh improvements are given. These example solutions demonstrate that an effective mesh for a given error tolerance can be obtained in a few steps of the analysis processes.

• 한국분말재료학회지
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• 제9권4호
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• pp.211-217
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• 2002

It is well known that the powder injection molding(PIM) process can overcome the shape limitations of traditional powder compaction, the costs of machining, the productivity limits of isostatic pressing and slip casting, and the defect and tolerance limitations of conventional casting. Increasing demands from industry for not only the dimensional accuracy nut mechanical strength in PIMed parts have had much effort focused on the investigation of mechanical properties of mechanical strength in PIMed parts have had much effort focused on the investigation of mechanical properties of sintered parts formed with high-strength metallic powders. The 17_4 PH $10\mu{m}$ were injection-molded into flat tensile specimens. Sintering of the compacts was carried out at the various temperatures ranging from 900 to $1350^{\circ}C$. Sintering behavior of the compacts and tensile properties of sintered specimens were investigated.

• 한국안전학회지
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• 제17권4호
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• pp.1-4
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• 2002

A automatic production system was developed for high productivity and safety. The semi-progressive die was unfavorable for more productivity, safety, material extravagance and incongruent high-speed production. Developed progressive die is suitable for the high production and guarantee triple production by acceptance of three array type for automobile adjust plate. We adopt Pro-$Engineer{\circledr}$ for three dimensional computer aided design suitable for the disassembly and assembly evaluation. The conclusion of this study is as follow. First, press die parts solid modeling system is built by using Pro-$Engineer{\circledr}$ through this research and verified allowable tolerance and possibility of assembly and disassembly of parts. Therefore we can reduce die manufacturing time and cost. Second, We produce 1000 units pet hot coil 1ton by traditional method, but we can acomplish material saving effect about 12% as 120 units in case of new progressive die. Fourth, we acomplished manufacturing cost curtailment effect more than 20% in comparison with traditional method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.290-292
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• 1994

This paper presents a methodology for the electric field analysis of substation. For the electric field analysis of substation, the electrodes(substation busbars) must be represented by finite line with nonlinear charge density. In the case of dividing finite line into uniform segments, a large number of variables have to be used to obtain the accuracy within a desired tolerance. To deal with the problem, nonuniform charge arrangement modeling method is suggested. To reduce potential calculation errors, the linear charge density function is considered particularly for the segment charge model ling. If the charge arrangement is improper, the accuracy not improved regardless of increment in the number of segments. This paper proposes an optimal charge arrangement method through potential error analysis. And, the optimal charge arrangement function is formulated by a lot of simulation results.

• 한국기계가공학회지
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• 제18권7호
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• pp.77-82
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• 2019

In this study, we study the change of surface roughness during cutting machining by changing the cutting conditions such as feed rate and spindle velocity with chromium molybdenum steel (SCM415) material and TiCN and TiAlN coated end mill tools. The surface roughness value of the test specimen for SCM415, was found to be 3,000 rpm in TiCN coated end mill and $0.634{\mu}m$ in surface roughness at a feed rate of 100 mm/min. In the TiAlN coated end mill, 300 mm/min, the surface roughness was the best at $0.699{\mu}m$. The overall average surface roughness of each coating tool was better than that of TiAlN.