• 대한기계학회논문집
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• 제14권6호
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• pp.1515-1522
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• 1990

본 연구에서는 천연다이아몬드의 인선형상을 R형과 S형으로 구분하여 제작하 고 미세이송과 절삭속도 변화를 주어 이에 얻어지는 표현거칠기, 칩 생성기구 및 경면 성을 검토하였다.

• 한국정밀공학회지
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• 제19권3호
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• pp.101-106
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• 2002

This paper presents an experimental investigation of high speed machining of dies and molds. Several critical issues involved with the high speed machining of QRO90 tool steel of hardness up to HRc62, have been studied and explained from a detail analysis of experimental observations. The experiments were performed using ball end mills. The effect of different process parameters on tool life and surface finish produced was also investigated. The cutting parameters involved were; cutting speeds in the range of 100 to 40 / m/min, axial depth of cut from 0.1 to 0.5mm, pick feed of 0.1 to 0.5mm. Run out and acceleration signals were observed during the experiment to investigate cutting slates. Compressed air and flood coolant were used and the effect of coolant on tool life was also determined.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.912-916
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• 2000

The term ‘High Speed Machining’has been used for many years to describe end milling with small diameter tools at high rotational speeds, typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry fur the machining of light alloys, notably aluminium. In recent you, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. And the end mill is an important tool in the milling process. A typical examples for the end mill is the milling of pocket and slot in which a lot of material is removed from the workpiece. Therefore the proper selection of cutting parameter fur end milling is one of the important factors affecting the cutting cost. The one of the advantages of HSM is cutting thin-walled part of light alloy like Al(thinkness about 0.1mm). In this paper, firstly, we study characteristics of HSM, and then, we choose the optimal parameters(cutting forces) to cut thin-walled Al part by experiment.

• Journal of Advanced Marine Engineering and Technology
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• 제21권4호
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• pp.381-386
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• 1997

The offsetting method using geometric properties of B-spline control polygon is more faster than using of general normal vector in offset processing. But this method itself does not solve the prob¬lems of loop removal in normal offsetting. Generally the distance between neighborhood spans of B-spline control polygon is greater than the offset distance, the loops are occurred in offsetting. For generating of the more precision tool-path in NC machining, the loops of offset must be removed. In this paper, two methods for loop removal are introduced in offsetting of B-spline curve. One is using the intersection of B-spline control span which being occurred of the loop. The other is using two B-spline curve divisions divided from original B-spline curve or its offset curve. After the inter¬section point of loop was searched, the loop being removed to cusp. Also the method for filleting of cusp is inspected to more precision cutting. It is shown that the offsetting using B-spline control polygon is more effective in the sculptured surface machining.

• 한국정밀공학회지
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• 제27권9호
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• pp.86-93
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• 2010

Any relative deformation between the cutting tool and the workpiece at the machining point, results directly in form and dimensional errors. The source of relative deformations between the cutting tool and the workpiece at the contact point may be due to thermal, weight, and cutting forces. Thermal and weight deformations can be measured at various positions of the machine tool and stored in the compensation registers of the CNC unit and compensated the errors during machining. However, the cutting force induced errors are difficult to compensate because estimation of cutting forces are difficult. To minimize the error induced by cutting forces, it is important to improve the machining accuracy. This paper presents the pre-calculated method of form error induced by cutting forces. In order to estimate cutting forces, Isakov method is used and the method is verified by comparing with the experimental results. In order to this, a cylindrical-outer-diameter turning experiments are carried out according to cutting conditions.

• 한국정밀공학회지
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• 제16권10호
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• pp.35-44
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• 1999

The performance of interrupted cutting operations like milling is consideraly affected by cuter runout. In this study, cutter runout is selected as an important machining parameter for evaluation of machinability in ball-end milling and caused from misalignments of tool and holder, unbalanced mass of parts and tool deflection under machining. To evaluate the machinability due to cutter runout, the rotating accuracy of spindle, cutting force and surface roughness are measured. The rotating characteristics of spindle in each revolution speed were investigated by cutter runout in freeload. The predicted surface form of workpiece by measuring cutter runout data was compared with real surfaces. The results show that measuring runout with high response gap sensor is useful for studying the phenomenon of high-speed machining and the monitor surface form using in-process runout measurements in ball-end milling is possible.

• 한국CDE학회논문집
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• 제12권3호
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• pp.153-162
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• 2007

In this paper, we propose a knowledge-based method for generating CNC torch path for laser cutting of the outlines of planar shapes. The proposed method consists of two main phases: laser cutting knowledge construction and CNC torch path generation using the knowledge. In the first phase, cutting experiments are conducted on various operating parameters, and then empirical data are stored and analyzed to make up the knowledge of laser cutting. With this knowledge, we can inquire what a kerf width is for specific operating parameters. In the second phase, using the knowledge of laser cutting, CNC torch path is generated for cutting the outlines of the given planar shapes. This phase is basically based on the offset generation of each outline by a sequence of arc splines, where the offset distance is the same as the half of the kerf width determined from the constructed knowledge. The proposed method based on laser cutting knowledge makes full use of arc interpolators in CNC torch path generation. The method can efficiently reduce the number of path segments while keeping the torch path within the desired accuracy.

• 대한한의학원전학회지
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• 제21권4호
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• pp.237-241
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• 2008

"난경(難經)"의 오유혈(五兪穴) 이론(理論)이 가장 많이 제기되는 문제는 '육십팔난(六十八難)'의 오유혈(五兪穴)의 주치작용(主治作用)이다. "영추 본수편(靈樞 本輸篇)"에서는 다만 오유혈(五兪穴)의 명칭과 위치에 대해서 소개하고 있지, 계통적인 주치에 대한 설명이 없고, '육십팔난(六十八難)'에서 명확히 5가지 종류의 질병에 대해서 귀납(歸納)하고 오유혈(五兪穴)이 주관하는 병증(病證)을 분별하여 후세의 모범이 되고 있다. 그러나 "난경(難經)"에서 오유혈(五兪穴)에 대해서 물이 흐르는 형상을 비유하여 사지(四肢)에서 체간(體幹)으로 향하는 노선으로 설명하고 있는데, 이는 "내경(內經)"의 십이경맥(十二經脈)이 여환무단(如環無端)하는 체계와 전혀 부합하지 않아서 학문과 임상에 있어서 지금까지도 혼란을 야기하고 있다. 그동안 "갑골문자(甲骨文字)"를 해독하기 위한 심도 있고 다양한 연구가 진행된 결과 고문자(古文字)의 해독(解讀)잘못된 계산식을 위한 공구서(工具書)들이 많이 개발되었는데, 본 논문은 그러한 고문자(古文字) 해독(解讀)의 연구방법(硏究方法)을 통해 "난경(難經)"의 오유혈(五兪穴) 이론(理論)의 난제(難題)를 해결하고자 한 것이다. 예를 들어 정형수경합(井滎輸經合)에 대해서 "난경(難經)"의 '육십팔난(六十八難)'에서 "소출위정(所出爲井), 소류위형(所流爲滎), 소주위유(所注爲兪), 소행위경(所行爲經), 소입위합(所入位合)"이라고 설명한 그 것 중에서 출(出), 류(流), 주(注), 행(行), 입(入)과 정(井), 형(滎), 유(兪), 경(經), 합(合)의 글자를 고문자(古文字) 해독(解讀)의 측면에서 재해석함으로써 이를 의학적(醫學的)으로 활용할 수 있도록 그 실마리를 제공하였다.

• 소성∙가공
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• 제28권4호
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• pp.183-189
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• 2019

Cylindrical worm reducers are generally used in various fields and forms throughout the industry, and demand is increasing due to their role as an integral part of the industry. Market trends require high-load, high-precision components, and small-sized reducers with large loads. When using a cylindrical worm reducer, a reducer designed with a reduced center distance while maintaining the same output torque results in gear wear. To overcome this difficulty, an enveloping worm gear reducer is introduced and studied. In this paper, three types of end mill tools are used to evaluate the tooth profile accuracy for each tool shape during machining of the tooth profile for a non-developed surface worm thread. The effect of the endmill shape on the accuracy of the tooth profile was analyzed by performing 3D modeling of the surrounding worm tooth profile based on the Hindley method. In this study, we analyzed tooth profile accuracy, tooth surface roughness, and tooth surface machining time, etc. Through the study, efficient machining conditions for the enveloping worm gears and the influence of parameters on the process were presented.

• 한국기계가공학회지
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• 제20권7호
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• pp.15-24
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• 2021

In this paper, to analyze the types of surface morphology error according to factors that cause machining error, the experiments were conducted in the ultra-precision diamond machine using a diamond tool. The factors causing machining error were classified into the pressure variation of compressed air, external shock, tool errors, machining conditions (rotational speed and feed rate), tool wear, and vibration. The pressure variation of compressed air causes a form accuracy error with waviness. An external shock causes a ring-shaped surface defect. The installed diamond tool for machining often has height error, feed-direction position error, and radius size error. The types of form accuracy error according to the tool's errors were analyzed by CAD simulation. The surface roughness is dependent on the tool radius, rotational speed, and feed rate. It was confirmed that the surface roughness was significantly affected by tool wear and vibration, and the surface roughness of Rz 0.0105 ㎛ was achieved.