• 한국기계가공학회지
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• 제18권10호
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• pp.27-33
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• 2019

The aviation industry has grown beyond the simple processing and assembling of aircraft parts and now designs and exports finished aircraft. In this study, the vertical CNC milling rotational speed and feed rate were parameters to investigate the life of tools according to their shape: (flat, round, and ball end mill) in the rough cutting of titanium. These tools are widely used in aircraft manufacturing and assembly. The purpose of this study is to measure the cutting temperature generated during the cutting process and calculate the rate of tool wear. This will be accomplished by measuring the tool weight before and after cutting the specimen and to compare it with the results of previous studies. Our study showed that the maximum cutting temperature increased as cutting time, tool rotational speed, and feed rate increased. The highest cutting temperatures were recorded for the ball, round, and flat end mill, respectively. Tool wear for the ball, round, and flat end mill increased as the speed and feed rate increased. The flat end mill exhibited the highest rate of wear from a minimum of 0.62% to a maximum of 2.88%.

• 한국기계가공학회지
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• 제20권1호
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• pp.57-65
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• 2021

With the increased utilization of CAM programs, end-mill processing is most commonly used for machining and metal processing. In particular, hole or shaft machining has high assembly precision, which inevitably leads to high utilization of end mills. However, the analysis of quality characteristics according to the process conditions of end mills is not performed systematically at the site, causing poor quality and productivity. The most influential factor of quality is the runout of the end mill. In this paper, the number of turns of the end mill, number of tool blades, cutting direction, and artificial runout volume were determined to identify the correlation between the epicenter, cylindricality, and surface roughness. Two types of end mills, three levels of runout, three levels of rotational speed, and two cutting directions were considered and 36 rounds of hole processing were conducted. For the analysis of shape characteristics according to the set process variables, the experimental planning method was applied to the measured specimen and the processing characteristics were analyzed according to the runout of the end mill through correlation analysis.

• 한국자동차공학회논문집
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• 제24권1호
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• pp.67-73
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• 2016

The application of titanium has been gradually rising because the utilizing ranges for low weight and high strength are rapidly increased by the need for improving the fuel economy in production industries such as the aviation and automotive in recent. The purpose in this study is to investigate the appropriate cutting conditions on the life of flat and round end mills by measuring the maximum cutting temperature relative to the machining time, and calculating the wear rates of cutting tool with the spindle speed and feed rate of vertical machining center as a parameter in the titanium roughing cut machining which is widely used in critical parts of aircraft, cars, etc. When the wetted roughing cut machining of titanium with a soluble cutting oil is conducted by the flat and round end mills, the maximum cutting temperatures for a variety of spindle speed and feed rate are measured at ten-minute intervals during 60 minutes by an infrared thermometer, and the wear rates of cutting tool are calculated by the weight ratios based on tool wear before and after the experiment. It is found that the maximum cutting temperature and the wear rates of cutting tool are raised as the cutting amount per tool edge is increased with the rise of feed rate, in this experimental range, and as the frictional area due to the rise of contacting friction numbers between tool and specimen is increased with the rises of cutting time and spindle speed. In addition, the increasing rate of maximum cutting temperature in the flat and round end mills are the highest for the cutting time from 50 to 60 minutes, and the wear rate of cutting tool in the flat end mill is 1.14 to 1.55 times higher than that in the round end mill for all experimental conditions.

• 한국생산제조학회지
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• 제8권2호
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• pp.116-116
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• 1999

In this study we propose a novel approach with which design engineers can define and design free-from surface more easily. Free-from surface is defined as a parameterics shape which consists of a set of contr ol points. Parametric shape which not only has the advantage of allowing users to perform design changes efficiently, but also provides designers with a natural design environment in which they can do their work more naturally and creatively. The objective of this study is to develop a PC level freeform surface modelling system which explicitly represents information of part geometry. In this study, freeform surface modeling system consist of three modules : freeform surface modeler, input/output modules and interface with Database. In recent year there are increasing demands for the 5-axis machining of a complicated shape. This study is the development of a CAM software system (or NC module) for the 5-axis machining of a general shape with a flat-end mill, a round-end mill, a ball-end mill.

• 패션비즈니스
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• 제5권2호
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• pp.105-115
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• 2001

When restoring a tomb of Songeun, Park Ik that damaged by typhoon in Kobubri, Chungdomyon, Mill Yang, Kyoung Nam in October 2000, a flower designed stone and fresco was discovered. Soneun Park Ik passed the civil service examination in Kongmin dynasty and was consecutively occupied Sajaedogam(司宰少監; regarded as one of second highest official rank). The fresco realistically depicts custom of ordinary people in end of Koryo, beginning of Chosun dynasty that it is considered as an important research material in study of ostumes. Therefore, this research intend to contribute to study of costumes in general public of Koryo that has insufficient study materials through study and analyze of costumes in the fresco with literature research. The number of figures in the fresco is presumed as 26-27 in all but clearly observed figures is only five women and four men and partly damaged figures are two men and two women. Women are worn relatively long yoo that can cover hip as an upper garment and Sang(裳) as trousers. The upper garments are all adjusted to right and has Jikryoung gik (straight collars) but there are strip attached collars or double collars among the Jikryoung gik. The length of Sang reaches to ankle and a waistband is trailed to below the knees. Most of hair are combed in the two sides and made a ring, moreover worn ceremonial coronet, which imply the ceremonial parade. Distinguished from the frescos of Koguryo, there are no women wearing Po(袍) also Yoo with Dae(帶) and without were coexisted. The mens costume is mainly appeared in two types. One(元) is Danryoungpo, Po with round collar and wearing a lozenge shaped crest with a brim, the other is Jikryoung Po, Po with straight collar, and wearing Ballib(拔笠), the latter is a costume of two man presumed as envoys. In the case of Danryoungpo, its length reached to ankle that shows decorum and in Jikryoungpo its length is below the knees that seem to offer practicality for envoys to guide a long journey. Both man and women are in decent cloth with a crest, which simple costume for ordinary people as a Chaksoopo that has comfortable length for movement and narrow sleeves. Songeun Park Ik actively worked under regency of One dynasty that influence of Mongol is seen in mans crest. There are some changes but including womens costume most of cloth are followed Korean traditional costume style.