• 한국산학기술학회논문지
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• 제10권10호
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• pp.2596-2601
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• 2009

후판의 맞대기 용접 시 용접부의 이면에 홈을 파는 가우징 작업은 숙련된 용접 작업과 그라인딩 작업을 필요로 한다. 기존의 가우징은 산소 아크 용접기를 이용하여 제거하고자 하는 부분을 용융시킨 뒤 고압 산소로 불어내는 방식으로 제거된 분진이 작업환경을 열악하게 하며 제거된 부분을 다시 그라인딩 작업으로 평탄화하는 후처리 작업이 필요하기 때문에 생산성을 크게 떨어뜨리고 있다. 이를 절삭에 의한 기계적 제거 작업으로 바꾸어 기존 용접법에 의한 가우징 작업의 단점을 보완하고 생산성을 향상시키고자 절삭 가우징 장치를 개발하고 실험하였다. 개발된 절삭 가우징 장치는 분당 재료제거량이 $13,565mm^3/min$으로 기존 용접법에 의한 가우징에 비해 작업효율이 약 3배 개선되었다. 또한 가공인건비가 1/3 수준으로 감소되는 것을 기대할 수 있으며 소음과 분진으로 인한 작업환경문제가 크게 개선됨을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.477-482
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• 2001

A study was performed to determine the optimum height for an arc air gouging of temporary attachments, which were attached at the pressure vessel made of low alloy steel. Frequently, the crack occurred in the base metal by the excessive heat input during an arc air gouging process to remove the temporary attachments. A numerical analysis by 2-dimensional finite element method was performed to calculate the temperature distribution in the base metal during the removal of temporary attachments. And then the mock-up test was performed to verify the numerical results. Numerical values showed good agreement with the experimental results. These results indicated that the defects due to the excessive heat input during an arc air gouging were dependent on the height of temporary attachments remained above hie main products.

• International Journal of CAD/CAM
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• 제7권1호
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• pp.51-60
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• 2007

This paper presents an algorithm of optimal cutting tool selection for machining of the point-based surface that is defined by a set of surface points rather than parametric polynomial surface equations. As the ball-end and fillet-end mills are generally used for finish machining in a 3-axis computer numerical control machine, the algorithm is applicable for both cutters. The optimum tool would be as large as possible in terms of the cutter radius and/or corner radius which maximise (s) the material removal rate (i.e., minimise (s) the machining time), while still being able to machine the entire point-based surface without gouging any surface point. The gouging are two types: local and global. In this paper, the distance between the cutter bottom and surface points is used to check the local gouging whereas the shortest distance between the surface points and cutter axis is effectively used to check the global gouging. The selection procedure begins with a cutter from the tool library, which has the largest cutter radius and/or corner radius, and then adequacy of the point-density is checked to limit the accuracy of the cutter selection for the point-based surface within tolerance prior to the gouge checking. When the entire surface is gouge-free with a chosen cutting tool then the tool becomes the optimum cutting tool for a list of cutters available in the tool library. The effectiveness of the algorithm is demonstrated considering two examples.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.439-444
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• 2004

A new efficient intelligent machining strategy named the Steepest Directed Tree method is presented in this study, which makes surface model discrete with triangulation meshes and the cutter paths track along the tree directions. In order to formulate these algorithms practically, it is deduced the multi-stage machining approach of uncut volume caused by cutter gouging in the course of milling using flat end mill. It is systematized the checking process the cutter interference by grouping the 6 kinds of gouging types, which yields the environment of connectivity data lists including CL-data, and then the multi-stage machining strategy, that minimizes uncut area by continuously sequencing the generative subsequent CL-paths, is shamed to determine the second tool path for the next uncut area and to compose the operating multi-stage cutting processes. The completed machining system of curved surfaces is evaluated by testing the practical machining experiments which have various kinds of shape conditions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.153-156
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• 1995

본 논문은 gouging이 있는 free-formed parametric surface 모델로부터 간섭영역을 찾아 공구간섭을 검사하고 이를 제거하여 실시간으로 3축 NC가공을 할 수 있는 방법을 제안한다. 제안되는 방법은 parametri surface로부터 cartesian 경로를 따라 offset surface를 구하고 정의된 가공평면과의 교차곡선을 구하는 것에서 부터 시작한다. 교차곡선으로부터간섭 loop의 형성 여부를 검사함으로써 간섭영역을 찾을 수 있고 간섭을 제거하기 위해 간섭영역내의 모든 CC점이 공구 중심으로 부터 최소한 공구를 벗어나 위치하도록 공구를 공구의 측방향으로 이동시켰다. 이 논문은 free-formed surface의 gouging 부위에서 발생하는 공구간섭을 신속히 제거하고 CL data를 생성하여 실시간으로 3축 NC 가공을 하기 위한 하나의 접근이다.

• 한국해양공학회지
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• 제33권6호
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• pp.556-563
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• 2019

The ice keel gouge and seabed interaction is one of the major considerations in the design of an Arctic pipeline system. Ice keel and seabed interaction engineering models based on experimental data, which give an explicit equation for estimating the ice gouging depth, have been suggested. The suggested equations usually overestimate the ice keel gouging depth. In addition, various types of numerical analyses have been carried out to verify the suggested engineering model equations in comparison to the experimental data. However, most of numerical analysis results were also overestimated compared with the laboratory experimental data. In this study, a numerical analysis considering the contact condition and geostatic stress was carried out to predict the ice keel gouging depth and compared with the previous studies. Considering the previously mentioned conditions, more accurate results were produced compared with the laboratory experiment results and the error rate was reduced compared to previous numerical analysis studies.

• 대한조선학회논문집
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• 제44권2호
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• pp.198-209
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• 2007

In this paper, we present the gouging and collision-free tool-path generation for manufacturing model propellers using the 5-axis NC machine. Because it takes much time to generate tool-paths when we use general purpose CAD/CAM systems, a specific system would be necessary for marine propellers. Overall manufacturing process is composed of two steps: roughcut and finishcut steps. The roughcut is conducted using only 3-axis for efficient machining and the finishcut is done using 5-axis for avoiding collision. The tool-path that might happen to gouging is searched and the tool position is also decided for avoiding interference between the tool and the propeller blades. The present algorithm is applied extensively to the surface piercing propellers. Some results are demonstrated for its validation.

• 한국정밀공학회지
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• 제32권8호
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• pp.705-711
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• 2015

Five-Axis machines can generate undesirable defects such as the undercutting and overcutting errors that frequently occur in the three-axis machining process. It is therefore necessary to develop a program for NC-code generation, whereby the cutter posture is considered to decrease the occurrence of defects. In previous studies, the Easy-Impeller CAM(E-ICAM), an automatic CAM program used for the five-axis machining of impellers, was developed; however, when E-ICAM is used to machine an impeller, it is possible to gouge the hub and blade. Therefore, the aim of this study is the establishment of a formula for each type of endmill to minimize gouging according to the cutter posture, in consideration of several factors that affect accuracy in the machining of an impeller. This study also aimed to improve the performance and accuracy of E-ICAM in the manufacturing of impellers.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1991년도 특별강연 및 추계학술발표 개요집
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• pp.102-104
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• 1991

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2000년도 특별강연 및 추계학술발표대회 개요집
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• pp.70-72
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• 2000