• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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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.

• 한국기계연구소 소보
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• 통권15호
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• pp.75-87
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• 1985

A review was performed on fatigue life prediction and strength evaluation of shot peened parts. Fatigue strength of machine parts can be improved by shot peening due to compressive residual stresses on such parts. Compressive residual stress cannot be uniquely define by peening intensity. Several measuring methods of residual stress and the principle of hole drilling method are presented. Exploratory measurement of residual stress was performed on the shot peened SM35C plate with the hole drilling method. Fatigue life and failure location of shot peened parts under bending load can be predicted by a damage parameter which is incorporated with material properties, residual stress, and applied stress conditions. Some method are presented to predict the fatigue strength of shot peened parts at any given life. Shot peening gives its full benefit to the notched machine parts of high strength steels.

• 품질경영학회지
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• 제23권3호
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• pp.140-155
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• 1995

This paper proposes a quality control method of assembly parts based on parts inspection information. We use the parts inspection information for reduction of defective fraction in assembly and prediction of assembly quality. At first, we build the functional relationship between parts and assembled unit by regression analysis. Secondly, if we use the inspection informations of parts which are estimators of means and variances, we can predict the nonconforming probability of assembled unit and propose the best assembly method. In a case study, we showed the efficency of the proposed method in two part assembly.

• 한국국방경영분석학회지
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• 제24권2호
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• pp.146-161
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• 1998

This article develops model of the nonstationary state behavior of the multiechelon spare parts provisioning systems. This study is concerned with a problem of determining the near optimal requirements level of the spare parts, especially Concurrent Spare Parts(CSP). CSP is supplied with the procurement of new equipment system, and is used to sustain the equipment without resupply during the initial coverage period. We consider this situation as a multiechelon inventory model with several bases and one depot. And we assume an equipment system which consists of many types of parts would grounded if one of the parts fail. Also this multiechelon CSP problem is considering the nonstationary poisson failure process and nonstationary exponential repair process in a dynamic environment. We develop an efficient computational procedure to find the near optimal number of spare parts minimizing the total expected cost, while achieving the required system availability. Finally we present a simple example of suggested method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.337-341
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• 2002

In these day, micro systems have gained attention with development of advance technologies. Researches about the fabrication of micro parts are actively made in the whole world. Among the researches, technology for micro injection molding machine is one of the key issues for fabrication of micro parts. In this study, we developed a micro injection molding machine for micro parts. To achieve this, injection unit was constructed using a screw with diameter of 12 mm. Clamping unit with clamping force of 1.75 kgf/$\textrm{cm}^2$ was constructed. Also verification test fur fabrication of micro parts was performed. It was performed that the micro injection molding machine can fabricate micro parts based on the result.

• 대한안전경영과학회지
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• 제11권1호
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• pp.93-101
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• 2009

The use of the gas turbine for power supply is increasing recently. Accordingly, the operation and maintenance cost of the gas turbine is gradually increasing and the various efforts to cut the cost are needed. For an operation and maintenance cost saving of the gas turbine, reductions of the new purchasing charge and the reproduction repair cost of the hot gas parts are required through more effective operation and life management methods for the hot gas parts. The hot gas parts are the main parts of the gas turbine and they are replaced with the periodic. In this research, efficient operation and life management methods for the hot gas parts were presented with the cases. The methods were analyzed and verified based on real data and the cases for improving a lifetime were utilized in the field.

• 산업경영시스템학회지
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• 제20권43호
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• pp.249-263
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• 1997

This paper addresses the parts route selection and economic design in flexible manufactuirng system (FMS). Parts are processed through several stage workstations according to operation sequences. The machine of each workstation can do multiple operation functions. And the operation stage of a part can be processed in several workstations, which are non-identical in functional performance. The objective of this paper is to determine the processing routes of parts, number of machine at each workstation, number of vehicle and makespan time. Two models are suggested. One is assumed that the operation stage of parts can be processed at the only one among several available workstations. Other is assumed that the operation stage of parts is allowed to be processed at several workstations. Parts are transported by automated guided vehicles (AGVs). The decision criteria is to minimize the sum of processing cost, travel cost, setup cost and overhead cost. The formulation of models is represented. A solution algorithm is suggested, and a numerical example is shown.

• 한국국방경영분석학회지
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• 제16권2호
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• pp.75-82
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• 1990

When the new equipment or weapon system is introduced to the operating unit its repair facilities and spare parts supply channels are not regularly generated. therefore, its required spare parts are initially supplied at the same time when the main equipment is deployed. For these circumstances, we are faced with the following problems : the first one is to decide the budget amounts to acquire the spare parts, the second is to choose the amounts of initial provisioning spare parts, and the third one is how to allocate the given budget for the initial provisioning spare parts. This paper emphasizes on determining the budget amounts, but also suggests the spare parts allocating methods.

• 한국정밀공학회지
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• 제13권7호
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• pp.122-132
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• 1996

It can be expected that the tolerances of the parts are assigned systematically and thus the parts are designed considering the assemblability in advance in the design stage, if the tolerances can be stored together with the geometric model of the parts and the assemblability of the parts is verified in the computer. In other words, an example of the concurrent engineering is realized. To verify the concepts described above, a new method is proposed to verify the assemblability when the tolerance information and the geometric model of the parts of an assembly are given. This method determines the assemblability by subdividing the range of relative motion between parts until the subdivided region corresponding to free of interference can be found.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.571-576
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• 2001

Hydroforming, the new production technology, has been used to manufacture many parts of vehicle in the recent auto industry. When Hydroforming is applied, it is possible to make parts simplification and flexible alteration of section shape in many advantages such as weight reduction, number of parts reduction or performance improvement. This research into shape optimization which reduces number of parts and weight maintaining performance was achieved. In this paper, the COWL CROSS BAA and MT'g BAKT parts of A car STEERING support SYSTEM was introduced by using Hydroforming.