• 한국기계가공학회지
• /
• 제7권3호
• /
• pp.30-35
• /
• 2008

As demands for being economical, precise drilling process is on the increase. Therefore, the objective of this study is to develop a step cutter that can be controllable through micro dimension and can be changed from separate manufacturing processes of drilling and boring into an integrated one. In order to attain this object the step cutter is designed with a 3D geometric modeling and the design could be modified easily by using parametric modeling methodology. Also, collision is not occurred during manufacturing process because of cutting simulation. The step cutter is assembled by parts made up of 5-axis machining and sintering. Validation tests are accomplished. They show that developed cutter has characteristics such as reduction of machining time as well as the good surface roughness of the machined hole. Indeed, reliability could be obtained from a durability test.

• 한국CDE학회논문집
• /
• 제9권3호
• /
• pp.246-252
• /
• 2004

Presented in this Paper is a Micro Machining Service .(MIMS) based on the World Wide Web technologies. In order to ensure easy access to the service, the web browsers are used as the user interface. The pan geometry as an STL file is uploaded with process parameter for 3-axis CNC milling. Depending on the predefined user level, novice or expert, the user interface requires different parameters for process planning. An STL-based CAM resides in the server and automatically provides NC codes upon user's request. Tool-paths for scanning and pencil-cut, which are interference-free and precise, are created by the curve-based polyhedral machining method. A couple of sample parts were fabricated by a micro endmill with 127 fm diameter. From the tests, the parts fabricated by scanning followed by pencil-cut resulted in less error(within 2%) than the parts machined only by scanning tool-path.

• 산업공학
• /
• 제15권2호
• /
• pp.147-151
• /
• 2002

Presented in this paper is a prototype of dedicated CAM system for a human bust, not a relief, machining. The input of this system is a STL file which comes from measuring machine, and the output is machining data for a 3-axis CNC milling machine with an index table. The system consists of three main modules, which are shape import and transformation, modeling of jig and fixture, and calculation of machining area. Proposed system architecture and the main modules are briefly described. To get machining region for semi-finish and finish machining stages, two concepts of machining area, machinable and scannable, were tried. Machinable area was suitable for the purpose.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.904-909
• /
• 2004

In this paper a web-based micro fabrication system is discussed. A commercial CAD and a web browser were used as its user interfaces. In these user interfaces the concepts of Design for Manufacturing (DFM) was implemented providing the fabrication knowledge of micro machining to the designers. Simple databases were constructed to store the fabrication knowledge of materials, tools, and micro machining know-how. The part geometry was uploaded to the web server of this system as an STL (Stereo Lithography) format with process parameters for 3-axis micro milling. A Slice-based process planner automatically provides NC codes for controlling micro stages. A couple of micro parts were fabricated using the system with micro endmills. This design and manufacturing system enables network users to obtain micro-scale prototypes in a rapid manner.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.471-474
• /
• 2004

In this paper, a NURBS surface interpolator is proposed which can deal with shapes defined from CAD/CAM programs on a surface basis and can improve contour accuracy. The proposed interpolator is based on newly defined G-codes and includes online tool-path planning suitable for NURBS surface machining. The real-time interpolation algorithm, considering an effective machining method for each machining process and minimum machining time, is executed in an online manner. The proposed interpolator is implemented on a PC-based 3-axis CNC milling system and evaluated through actual machining in terms of machining time and regulation of feedrate and cutting force in comparison with the existing method.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.170-173
• /
• 2004

In this paper a web-based micro fabrication system is discussed. A commercial CAD and a web browser were used as its user interfaces. For the user interfaces, the concepts of Design for Manufacturing (DFM) were implemented providing the fabrication knowledge of micro machining to the designers. Simple databases were constructed to store the fabrication knowledge of materials, tools, and micro machining know-how. The part geometry was uploaded to the web server of this system as an STL (Stereo Lithography) format with process parameters for 3-axis micro milling. A Slice-based process planner automatically provides NC codes for controlling micro stages. A couple of micro parts were fabricated using the system with micro endmills. This design and manufacturing system enables network users to obtain micro-scale prototypes in a rapid manner.

• 대한기계학회논문집
• /
• 제18권6호
• /
• pp.1483-1495
• /
• 1994

A quantitative analysis of a surface roughness for a precision machining of a sculptured surface in milling process is treated under superposition theory in this paper. The geometrical surface rouhgness is calculated as a function of feed per tooth, path interval, radii of tool and cutting edge, and radii of curvatures of workiece. Through machining experiments in a 3-axis machining center, we confirmed the adequacy of the adequacy of the analysis. While cutter mark is neglegible in ball endmilling, it is significant in flat endmilling. When feed per tooth is very small, flat endmilling gives superior finish to ball endmilling. In flat endmilling, cutting condition and cutter path should be strategically chosen to balance the cutter mark height and cusp height.

• 한국CDE학회논문집
• /
• 제10권6호
• /
• pp.421-431
• /
• 2005

This paper introduces a new approach for saving build time of hybrid rapid prototyping by decomposing a part into minimum number of layers. In the hybrid rapid prototyping, a part of a complicated shape is realized by adding layers of a simpler shape, each of which is obtained by machining a sheet of constant thickness from its top and bottom surfaces. Thus it is desired to decompose a given part into the minimum number of layers while guaranteeing each layer to be fabricated from the given sheets using a 3-axis milling machine. To satisfy these requirements, a concave edge-based algorithm is proposed to decompose a part into layers by considering the tool accessibility, the total number of layers, and the allowable sheet thickness.

• 한국산업정보학회논문지
• /
• 제9권1호
• /
• pp.7-16
• /
• 2004

효율적인 최종 NC코드를 만들어내기 위해서 공구경로는 효과적인 방법으로 결정되어 져야한다. 이는 3축 CNC 공작기계상에서 자유형상의 벽을 가진 자유곡면을 가공할 때 특히 중요하다. 많은 CAD/CAM 시스템들은 자유곡면가공을 위한 NC코드 생성 시 직선 보간을 이용한다. 그러나 이 방법은 가공된 바닥 표면의 매끄러움과 가공시간, 그리고 CL파일 사이즈를 줄이기 위해서 보정되어야 한다. 곡선 가공이 이러한 문제들을 줄이기 위한 해결책이 될 수 있다. 단일화된 황삭과 정삭 알고리즘과 공구경로가 그래픽으로 시뮬레이션 되었다. 본 연구에서는 자유곡면 바닥을 가진 파켓을 3축 CNC 공작기계를 이용하여 일반적인 파켓 밀링을 위한 직선 보간과 직선+아크를 혼합한 보간을 위한 NC 공구경로 데이터를 만들기 위한 3D 격자 항행 알고리즘을 개발하였다.

• 한국산학기술학회논문지
• /
• 제10권6호
• /
• pp.1157-1163
• /
• 2009

CNC 공작기계들을 이용한 품질향상과 생산성 향상을 위하여 2,3축 CNC 공작기계들에 부가축(2축)을 추가하여 생산 공정개선을 위해 노력하고 있다. 일반적인 CNC 공작기계들의 가공공정보다는 가공물의 공정간 이동이 현저히 줄어들기 때문에 생산성 향상과 더불어 정밀도 유지가 향상되기 때문이다. 그런데 기계가공 현장에서는 일반적으로 CAD(2.5D)와 CNC 공작기계의 수동프로그램 작업에 익숙한 작업들이 많다. 따라서 부가축을 추가한 CNC 공작 기계들의 원활한 활용을 위해 CAD/CAM의 VBScript을 활용하여 다축, 다공정 가공프로그램을 편리하게 작성할 수 있도록 한 것이다. VBScript을 컴파일하여 CAD/CAM Software(2.5D)에서 밀링용 Face Cutter의 Insert Tip 자리를 대상으로 수행한 결과 수동 프로그램 작성 시간 단축은 물론 복잡한 Multi CAD/CAM Software보다는 접근성이 편리하며, 다양한 제품들을 빠르게 프로그램 할 수 있었다.