• Title/Summary/Keyword: NC Machining

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A Study on Verification of NC Code of Multi-spindles Drilling for Tube Sheet in Heat Exchanger (열교환기 Tube Sheet의 다축드릴가공 검증에 관한 연구)

  • Oh, Byeong-Hwan;Lee, Hui-Gwan;Yang, Gyun-Ui
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.2
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    • pp.79-83
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    • 2001
  • A verification of multi-spindles drilling NC data is presented. The drilling of multi-spindles can offer productivity over three times as fast as that of single spindle. The most important things in machining tube sheet are precision of hole position and machining time. The drilling of multi-spindles has difficulties in controlling many motors to drive spindles and assign a correspondent number to each spindles. Multi-spindles drilling has different codes from CNC milling ; many subroutines, assignment of spindle, and so on. The conventional method, which inspects the NC code of the drilling, is to drill holes on a thin plate or tube sheet previously. The method results in low productivity because it consumed long machining time and welding for correction. This paper describes details of multi-spindles NC code and operation of multi-spindles drilling machine. A verification software of the multi-spindles drilling NC code is developed on the details.

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Development of CAM system for 5-Axis NC machining of sculptured surfaces (자유곡면의 5축 NC 가공을 위한 CAM 시스템 개발)

  • Jun, Cha-Soo;Park, Se-Hyung;Jun, Yong-Tae
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.1
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    • pp.52-61
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    • 1993
  • Developed in this research is a CAM system for 5-axis NC Machining of sculptured surfaces. We identify problems in generating 5-axis NC data and propose methods of overcoming them. Issues discussed in this paper are: kinematic modelling of NC machines; determination of cutter position (location and orientation); check of machine work-range; linear trajectory plann- ing ; calculation of feedrate number. The proposed system has been implemented in FORTRAN77 on the Personal IRIS EWS, and it also constitutes a module of the CAD/CAM system 'CASSET' developed in KIST CAD/CAM lab.

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A unified rough and finish cut algorithm for NC machining of free form pockets with general polygon - Part 1. Simulation (일반적인 내벽을 가진 자유바닥 곡면 파켓의 NC 가공을 위한 단일화된 황삭과 정삭 알고리즘 - Part 1. Simulation)

  • Park, Yong-hoon;Cho, Chi-woon;Kim, Sang-jin
    • Journal of Korea Society of Industrial Information Systems
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    • v.9 no.1
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    • pp.7-16
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    • 2004
  • The tool path needs to be determined in an efficient manner to generate the final NC (numerical control) code for efficient machining. This is particularly important in machining free form pockets with an arbitrary wall geometry on a three-axis CNC machine. Many CAD/CAM systems use linear interpolation to generate NC tool paths for curved surfaces. However, this needs to be modified to improve the smoothness of the machined bottom surface, reduce machining time and CL (cutter location) file size. Curved machining can be a solution to reduce these problems. The unified rough and finish cut algerian and the tool motion is graphically simulated. In this paper, a grid based 3D navigation algorithm for generating NC tool path data for both linear interpolation and a combination of linear and circular interpolation for three-axis CNC milling of general pockets with sculptured bottom surfaces is developed.

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Development of Machining Simulation System using Enhanced Z Map Model (Enhanced Z map을 이용한 절삭 공정 시뮬레이션 시스템의 개발)

  • 이상규;고성림
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.551-554
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    • 2002
  • The paper discusses new approach for machining operation simulation using enhanced Z map algorithm. To extract the required geometric information from NC code, suggested algorithm uses supersampling method to enhance the efficiency of a simulation process. By executing redundant Boolean operations in a grid cell and averaging down calculated data, presented algorithm can accurately represent material removal volume though tool swept volume is negligibly small. Supersampling method is the most common form of antialiasing and usually used with polygon mesh rendering in computer graphics. The key advantage of enhanced Z map model is that the data structure is same with conventional Z map model, though it can acquire higher accuracy and reliability with same or lower computation time. By simulating machining operation efficiently, this system can be used to improve the reliability and efficiency of NC machining process as well as the quality of the final product.

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Generation of 5-axis NC Data for Machining Turbine Blades by Controlling the Heel Angle (Heel angle 조정에 의한 터빈 블레이드의 5축 NC가공 데이터 생성)

  • 이철수;박광렬
    • Korean Journal of Computational Design and Engineering
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    • v.4 no.2
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    • pp.110-120
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    • 1999
  • In general, turbine blades are usually machined on 5-axis NC machine. The 5-axis machining of sculptured surface offers many advantages over 3-axis machining including the faster material-removal rates and an improved surface finish. But it is difficult and time-consuming to generated interference-free 5-axis tool path. This paper describes research on the algorithm for generation of an interference-free 5-axis NC data for machining turbine blades. The approach, using the section profile derived from the intersection of cutting planes with a triangulated-surface approximation, includes (1) CL-data generation by detecting an interference-free heel angle (2) the calculation method for finding a adaptive feed-rate value, and (3) the inverse kinematics depending on the structure of 5-axis machine.

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A Process Planning System for Machining of Dies for Auto-Body Production-Operation Planning and NC Code Post-Processing

  • Dongmok Sheen;Lee, Chang-Ho;Noh, Sang-Do;Lee, Kiwoo
    • International Journal of Precision Engineering and Manufacturing
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    • v.2 no.3
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    • pp.69-78
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    • 2001
  • This paper presents a process and operation planning system and an NC code post-processor for effective machining of press dies for production of cars. Based on the machining feature, major parts of press dies are categorized into 15 groups and a standard process plan is defined for each group. The standard process plan consists of a series of processes where a process is defined as a group of operations that can be done with one setup. Details such as cutting tools, cutting conditions, and tool paths are decided at the operation planning stage. At the final stage of process and operation planning, the NC code post-processor adjusts feedrates along the tool path to reduce machining time while maintaining the quality. The adjustment rule is selected based on the machining load estimated by virtual machining.

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An Expert System for NC Part Programming (ESPP-1) (NC파트 프로그래밍을 위한 전문가시스템)

  • 정선환
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.11
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    • pp.3091-3097
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    • 1994
  • An expert system for NC part programming of NC lathe (ESPP-1) is developed as a part of Computer-Adied Manufacturing system. Conventional computer-assisted part programming system essentially requires an NC part programmer who is an expert in NC part programming. But the developed ESSP-1 can allow an inexperienced person to make an excellent NC data for the NC Lathe without any problem, since the system has a knowledge base composed of EIA and ISO NC code, feed rate, spindle speed, machining coordinates selection, and tool selection etc., which were directly evoked from some skilled NC part programmers, and referenced some machining handbooks. This paper discusses the algorithm of the expert system for NC part programming of the NC lathe (ESPP-1) and the performance comparisons between the developed expert system and the conventional system.

Blending between machining data of surfaces (가공데이터로 주어진 곡면 간의 블렌딩)

  • Ju, Sang-Yoon;Jun, Cha-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.1
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    • pp.108-113
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    • 1993
  • This paper proposes a method for obtaining blend surfaces between machining data of surfaces. This blending algorithm consists of trangation, detection, tracing, construction of blend surfaces, and generation of machining data for the blend surfaces. Inpus of the algorithm are a blend radius and machining data of surfaces to be blended. CL data as well as CC data can be applied as an input machining data of the algorithm.

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A 5-Axis NC Machining Strategy Support System for an Impeller (임펠러 5축 NC가공을 위한 가공전략수립 지원시스템)

  • Cho, Min-Ho;Kim, Dong-Won;Heo, Eun-Young;Lee, Chan-Gi
    • IE interfaces
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    • v.21 no.4
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    • pp.411-417
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    • 2008
  • An impeller is a type of high-speed rotor that is used to compress or transfer fluid under high-speed and pressure at high temperatures. The impeller is composed of an axial hub and several blades attached along the hub. The weight and shape of an impeller must be balanced, because their imbalances can cause noise and vibration, which can lead to the breakage of the impeller blades during operation. Thus, the hub and blades of an impeller are commonly machined in a 5-axis NC machine to obtain qualified surfaces. The impeller machining strategy or process plan can not be easily obtained due to the complex, overlapped and twisted shapes of impeller blades. Skillful machining process planners may generate appropriate machining strategies based on their experiences and floor data. However, in practice most shop floor data for the impeller machining is not well-structured such that it does not effectively provide a process planner with information for machining strategies and/or process plans. This paper reports the development of a case-based machining strategy support system (CBMS) that employs case-based reasoning to obtain the machining strategy of an impeller by using the existing machining strategies of the shop floor. The CBMS generates impeller machining strategies through a stepwise reasoning process considering the similarity features between the blade shapes and machining regions. A case study is provided to demonstrate that CBMS can generate useful machining strategies facilitating process planners. The developed system can simulate the tool paths of impeller machining and runs on the web.

Implementation of NURBS interpolator (NURBS 보간의 적용)

  • 최인휴;양민양;이강주;김찬봉
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.51-54
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    • 2002
  • This paper deals with an implementation of NUBS interpolator and presents the process of its integration into PC-NC. For more accurate feed, NURBS algorithm is improved. Also, Evaluation of real time NURBS interpolator is provided to verify fred accuracy and geometrical accuracy of NURBS curve. NURBS machining of fee surface is simulated on the real time NC simulator so that machining time is compared to that of linear path machining.

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