• 한국기계가공학회지
• /
• 제1권1호
• /
• pp.123-132
• /
• 2002

In this study, the static and dynamic characteristics of endmilling process was modelled and the analytic realization of chatter mechanism was discussed. In this regard, We have discussed on the comparative assessment of recursive time series modeling algorithms that can represent the machining process and detect the abnormal machining behaviors in precision endmilling operation. In this study, simulation and experimental work were performed to show the malfunctional behaviors. For this purpose, new recursive least square method (RLSM) were adopted for the on-line system identification and monitoring of a machining process, we can apply these new algorithms in real process for detection of abnormal chatter. Also, The stability lobe of chatter was analysed by varying parameter of cutting dynamices in regenerative chatter mechanics.

• International Journal of Quality Innovation
• /
• 제5권1호
• /
• pp.85-109
• /
• 2004

Supplier quality management (SQM) is considered as a proactive approach in the buyers' perspective to seek for continuous supply quality improvement and collaborative ongoing alliance between buyers and suppliers. Therefore, it is important for the buyers to understand their circumstances for managing their suppliers, and thereby to search for an improved way to rectify managerial deficiencies, if any. This paper aims to identify the critical factors of SQM, and then propose a hierarchical framework which can facilitate the assessment of their SQM performance in the buyers' perspective and also serve as a working tool for managing supply quality performance.

• 한국생산제조학회지
• /
• 제19권5호
• /
• pp.631-636
• /
• 2010

SNCM420 steel is one of the cam shaft materials which are used in the supply unit for ship engine cam shaft. In this study the assessment of cutting behavior was conducted for the SNCM 420 steel and SM45C steel with various cutting conditions as depth of cut 0.5, 1.0, 1.5, 2.0mm and feed rate 0.1~0.3m/rev. The controlled chip was produced in feed rate 0.2, depth of cut 1.0 for SNCM420 and feed rate 0.2, depth of cut 2.0 for SM45C. There is no difference cutting force between SM45C and SNCM420 steels.

• 한국식생활문화학회지
• /
• 제3권3호
• /
• pp.293-299
• /
• 1988

34 packaged meal (Dosirak) manufacturing establishments were assessed in terms of working environment, production and transportation practices. Questionnaires and facility check-lists were developed. Most establishments were small in business, and production personnel as well as production facilities were insufficient compared with production capacity of establishments. Mean production capacity for packaged meals in terms of optimum and maximum levels were 6,500 and 15,166 meals in large sized establishments; 2,662 and 8,301 in medium; and 2,112, and 4,733 in small respectively. Those figures indicate potentially hazardous practices in production especially in small and medium sized establishments. Most meals were produced to order. Transportation facility and kitchen space were assessed as insufficient.

• 한국기계가공학회지
• /
• 제3권1호
• /
• pp.52-58
• /
• 2004

The material used is a commercial magnesium based alloy AZ31(Mg-3Al-1Zn)sheet with a thickness of 1.0mm. Uniaxial tension tests at warm temperature were carried out to investigate the material characteristics of K, m, and n. A warm drawing process with a local heating and cooling technique was developed to improve formability in this study with results of uniaxial tension tests because it is very difficult for Mg alloy to deform at room temperature by the conventional method. The die and blank holder were heated up, while the punch was water-cooled during deformation. FE simulations considering heat transfer were executed with Mg alloy to investigate the Improvement of deep drawability. For the assessment of improvement those were compare with the results of no considering heat transfer and room temperature.

• 한국기계가공학회지
• /
• 제8권1호
• /
• pp.48-56
• /
• 2009

This paper presents the results of miniaturized micro milling machine tool development for micro precision machining process. Finite element analysis has been performed to know the relationship between design dimensional variables and structural stiffness in terms of static, dynamic, thermal aspects. Design optimization has been performed to optimize the design variables of micro machine tool to minimize the volume, weight and deformation of machine tool structure and to maximize the stiffness in terms of static, dynamic, and thermal characteristics. This study presents the assessment of the technology incentive for the minimization of machine tool in the quantitative context of static, dynamic stiffness, thermal resistance and thus the accuracy implications. This study can also be provided a basic knowledge for further research of micro factory development.

• 한국생산제조학회지
• /
• 제8권3호
• /
• pp.42-51
• /
• 1999

An experimental modeling of cutting and structural dynamics and the on-line detection of malfunction process is substantial not only for the investigation of the static and dynamic characteristics of cutting process but also for the analytic realization of diagnostic systems. In this regard, We have discussed on the comparative assessment of two recursive time series modeling algorithms that can represent the machining process and detect the abnormal machining behaviors in precision round shape machining such as turning, drilling and boring in mold and die making. In this study, simulation and experimental work were performed to show the malfunctioned behaviors. For this purpose, two new recursive approach (REIVM, RLSM) were adopted fur the on-line system identification and monitoring of a machining process, we can apply these new algorithm in real process for the detection of abnormal machining behaviors such as chipping, chatter, wear and round shape lobe waviness.

• 한국생산제조학회지
• /
• 제7권4호
• /
• pp.104-116
• /
• 1998

This paper provides a review of the performance for SM45C using the CNC lathe. Under the constant cutting area, the tool wear for large feed rate is more than the small feed rate, and the progress goes more rapidly as the cutting speed is increased. This is caused by the friction between the workpiece and the bite. The average cutting force increases as the feedrate increases, and decreases as the cutting speed increases. This is because the effective rake/shear angle becomes smaller as the feedrate becomes larger. The higher is the cutting speed and the aspect ratio (the ratio for depth of cut to feedrate), the lower is the cutting force and the surface roughness. Also, for the optimal selection of the cutting conditions, many experimental graphical data were obtained. That is, the cutting force, the tool life, and the surface roughness were measured and investigated as the depth of cut and the feedrate changed. And the size effect was examined as the depth of the cut varied.

• 한국생산제조학회지
• /
• 제24권1호
• /
• pp.87-93
• /
• 2015

The dynamic responses of a telescope loaded on an STSAT-3 satellite were analyzed, and environmental tests were conducted to verify the reliability of the design. The space use telescope COMIS (compact imaging spectrometer) is a major payload of the STSAT-3 launched on November 21, 2013. Vibration responses such as the acceleration, displacement, and velocity with respect to random vibration and shock impulse inputs were obtained based on theoretical fundamentals in conjunction with finite element analysis. The main focus of this study was on developing technology for accurate and/or favorable modeling and analysis of the structure and fitting the results to that of experiments. Cutting-edge technology for manipulating the vibrations of a space use telescope is suggested.

• 한국기계가공학회지
• /
• 제15권4호
• /
• pp.134-140
• /
• 2016

Main Spindle System has effect on performance of machine tools and working quality as well as is required of high reliability. Especially, it takes great importance in producing automobiles which includes a large number of working processes. However, main spindle unit in Machine tools are often cases where damage occurs do not meet the design life due to driving in harsh environments. This is when excessive maintenance and repair of machine tools or for damage stability has resulted in huge economic losses. Therefore, this studying propose a method of accelerated life test for diagnosing and prognosis the state of life assessment main spindle system. Time status monitoring of diagnostic data - through the analysis of the frequency band signals were carried out inside the main spindle bearing condition monitoring and fault diagnosis.