• 품질경영학회지
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• 제41권1호
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• pp.109-118
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• 2013

혼합물 성분비와 공정변수들에 관한 실험 자료가 주어진 경우에, 주어진 실험 자료를 잘 설명하는 적절한 결합모형을 찾는 것은 중요한 과제이다. 우선 모형 선택 기준에 부합하는 시작모형의 후보들을 교적모형의 범주에서 찾고, 다음으로 선택된 시작모형을 완전모형으로 간주하여, 모형의 간결성의 원칙에 따라서 완전모형의 부분모형으로 구성된 적절한 결합모형들을 찾는데, 일반적으로 여러 개의 결합모형들이 추천된다. 주어진 실험 자료에 대한 적절한 모형으로 여러 개의 모형이 추천된 경우에, 엔지니어들의 실용적인 관심사는 각각의 결합모형에 대한 반응변수의 기대값의 예측치와 예측치의 표준편차의 추정치를 동시에 최적으로 하는 최적조건의 찾기이다. 이를 위한 실용적인 방법으로 반응변수가 여러 개인 다중 반응표면 분석에서 동시 최적화 기법을 활용한 최적조건을 찾는 방법을 제안하고, 잘 알려진 혼합물성분-공정변수 실험 자료에 대해서 Design Expert 8.0을 활용하여 적절한 결합모형들을 찾고, 이 모형들을 동시에 최적화하는 최적조건 찾기가 예시된다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.155-158
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• 1997

The investigation deals with of a intermediate process condition hving a bolt-shaped final product where it is required to extend tool-life in forging. In this study, optimization of the design variables is conducted by a genetic algorithm, where the fitness values are evaluated on the basis of FEM analysis model. The approach is applied to the determination of the intermediate process conditions which are optimal with regard to minimization of peak die pressure.

• 소성∙가공
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• 제11권4호
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• pp.312-322
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• 2002

In this study, an innovative semi-solid die casting technology to replace heavier cast iron compressor parts with lightweight aluminum castings was proposed, and the application possibility for home-appliance component was investigated. The most important factors regarding the semi-solid die casting process are the reheating process of the raw materials to the semi-solid state, specifications of the forming machine, the optimal injection conditions and die design. Materials used in this study were A3S7 and hSn alloys fabricated by the electromagnetic stirring process. The optimal injection conditions for semi-solid die casting process were Presented with the reheating conditions of the semi-solid materials. To investigate the effect of plunger tip shape on the formability and mechanical properties in semi-solid die casting process for complicated shape part, two kinds of plunger tip shape with long and short plunger tip taper are proposed.

• 한국정밀공학회지
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• 제15권12호
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• pp.14-20
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• 1998

Cutting fluid is a factor which has big effects on both machinability and environment in machining process. The loss of cutting fluids may be reduced by the optimization of machining parameters in process planning. In this study, the environmental impact of fluid loss is analyzed. The fluid loss models in milling process are constructed with the machining parameters. The models are utilized to obtain the optimal machining parameters to minimize the fluid loss. The factors with significant effects on the fluid loss are analyzed by ANOVA test. Finally, optimal parameters are suggested considering both machining economics and environmental impact. This study is expected to be used as a part of a framework for the environmental impact assessment of machining process.

• 한국생산제조학회지
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• 제18권3호
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• pp.261-269
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• 2009

Micro end-milling process is applied to fabricate precision mechanical parts cost-effectively. It is a complex and time-consuming job to select optimal process conditions with high productivity and quality. To improve the productivity and quality of precision mechanical parts, micro end-mill wear and cutting force characteristics should be studied carefully. In this paper, high speed machining experiments are studied to construct the optimum process design as well as the mathematical modeling of tool wear and cutting force related to cutting parameters in micro ball end-milling processes. Cutting force and wear characteristics under various cutting conditions are investigated through the condition monitoring system and the design of experiment. In order to construct the cutting database, mathematical models for the flank wear and cutting force gradient are derived from the response surface method. Optimal milling conditions are extracted from the developed experimental models.

• Design & Manufacturing
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• 제11권1호
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• pp.50-54
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• 2017

In this study, researches were conducted as follows. First, as the basic experiment, the cutting speed, feedrate, and the depth of cut were set as the process parameters, and by setting the surface roughness as the factor of measurement for each of the combinations, and the analysis about cutting tendency of the material was conducted by proceeding the turning process of Co-Cr-Mo alloy. Second, by setting the feature of the surface roughness according to the 'turning processing condition' that was confirmed in the previous experiment, and by applying the Taguchi Method, the conditions that influence the features of the surface roughness according to the 'turning processing condition' of Co-Cr-Mo was analyzed, and also by measuring the surface roughness according to each of the 'cutting conditions', the optimal processing condition was generated. As the result of analysis, it was possible to understand that the factor that mostly affects the surface roughness was the cutting speed, followed by the dept of cutting and transfer speed, and as for the optimal processing condition, it was possible to find that the cutting speed was 5,000rpm, and the depth of cut was 0.1mm, and the feedrate was 0.003mm/rev, and the value of the surface roughness at this point is $0.197{\mu}m$.

• 한국염색가공학회지
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• 제31권3호
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• pp.187-194
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• 2019

Blowing film was prepared using polyester elastomer with thermally expandable microcapsule to investigate the optimum blowing properties and the film making process. Physical properties including specific gravity, blowing efficiency, foaming shape, tensile strength and elongation of polyester film were tested by varying the process condition of temperature and revolution per minutes of the extruder. The lowest specific gravity of 0.709 can be achieved with excellent foaming cells at $210^{\circ}C$ and 50 RPM conditions. The highest tensile strength and elongation was shown at $210^{\circ}C$, 100 RPM and $230^{\circ}C$, 25 RPM conditions. However, most of the prepared polyester films showed over $1kg_f/mm^2$ of tensile strength which is reasonable value to use in film applications.

• 한국정밀공학회지
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• 제27권1호
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• pp.84-90
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• 2010

The cold forging Process applies surface lubricant coating in order to smooth the friction during the cold forging process. Currently, most of the lubrication processes apply the zinc phosphate coating, which requires 11 steps and disposes sludge. But the water based lubrication process, which has been newly developed, takes 3 steps only and does not cause sludge. In this study, we present the optimal condition of water based lubrication for the cold forging of axle shaft by an experimental design method. Experimental results with minitab shall be able to predict the optimum water based lubricating conditions for the cold forging processes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.1018-1021
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• 1997

This paper presents a result of simulation and improvement of grinding process for linear motion guide blocks. A simulation software, which is based on cylindrical grinding process. is used to predict the grinding wheel wear during the grinding process. To validate the simulation, the simulation result is compared with the experimental one. Simulation study is extended to obtain an optimal grinding condition for minimizing the grinding wheel wear. The optimal condition is validated through an experiment.

• 한국기계가공학회지
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• 제5권4호
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• pp.41-45
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• 2006

In recent years, the demands of the aspheric glass lenses increase since it is difficult to obtain the desirable performance in the plastic lens. Glass lens is manufactured by the forming with high precision mold core. This paper presents the analysis of optimal grinding condition of tungsten carbide(WC, Co 0.5%) using design of experiments(DOE). The process parameters are turbin spindle, work spindle, feedrate and depth of cut. The experiments results are evaluated by MINITAB software.