• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1024-1030
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• 1993

In manufacturing press die with free surface, grinding operation is an important post process for surface finish and dimensional accuracy. With the advancement of NC technology. surface grinding operation is increasingly replaced by the gantry type manipulator. As the mechanics for grinding operation is different from machining operation, conventional CAM system for machining operation is hard to apply. In this. paper, we develop a five-axis CAM system by which an efficient gantry trajectory can be planned and verified. The developed system consists of four conceptual modules; namely CAD, PROCESS. CAM, and ANALYSIS. In the CAD module, the machined surface is represented by CL-data or surface modeler, and process parameters are specified by the PROCESS module. Then, the CAM module generates a series of grinding paths based on the grinding mechanics together with process databases for tool spaces and grinding conditions. The generated paths are verified via ANALYSIS module. Validation via real experiments is left for further study.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.185-193
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• 2002

Most of NC machines are operated by Is06983 standard called G-code, which was developed in the early days of machine tools. This G-code limits hardware performance of the currently developed high-performance hardware & machine tools. By describing only movements of tool, almost all of information of previous production departments is lost, and the machining department cannot exchange information with other departments. For adjusting new hardware environment and direct communication of CNC machines with CAD/CAM software, ISO 14649, STEP -NC is researched. This new standard stores CAD/CAM information as well as operation commands of CNC machines. In this research, the new CNC machine operated by STEP-NC was built and tested. Unlike other STEP-NC milling machines, this system uses the STEP-NC file in form of XML as data input. It makes possible for STEP-NC machines to exchange information to other databases using XML. The mentioned system of this paper loads the XML file, analyzes it, makes tool paths of two5D features with information of STEP-NC, and machines automatically without making G-code. All of software is programmed with Visual C＋＋, and the milling machine is made with table milling machine, step motors, and motion control board for PC that can be directly controlled by C＋＋ commands. All modules of software and hardware were independent, it allows convenient for substitution and expansion of the milling machine. The example 1 in ISP14649-11 that had all information about geometry and machining and the example 2 that has only geometry and tool information were used to test automatic machining by the open-architecture milling machine.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1111-1117
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• 2003

NURBS (Non Uniform Rational B-Spline) is widely used in CAD system and NC data for high speed machining. Conventional CAM system changes NURBS surface to tessellated meshes or Z-map model, and produces linear tool path. The linear tool path is not good for precise machining and high speed machining. In this paper, an algorithm to change linear tool path to NURBS one was studied, and the machining result of NURBS tool path was compared with that of linear tool path. The N-post, post-processing and virtual machining software was developed. The N-Post post-processes linear tool path to NURBS tool path and quickly shades machined product on OpenGL view and compares a machined product with original CAD surface. A virtual machined model of original tool path and post-processed tool path was compared to original CAD model. The machining error of post-processed NURBS tool path was reduced to 43%. The original tool path and NURBS tool path was used to machine general model using same machine tool and machining condition. The machining time of post-processed NURBS tool path was reduced up to 38%.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.237-241
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• 1987

In this paper, the BTR (Behind the Tape Reader) type communication unit which interfaces the IEBM PC/XT to the FANUC 5M NC controller is developed, making it possible to send NC part program from the memory of IBM PC/XT to the NC controller. As an example of integration of CAD and CAM technologies, the machining of a two dimensional hand-written free line which incorporates the processes of geometric data acquisition using a digitizing tablet, automatic part programming and control of NC milling machine operation is demonstrated.

• 대한공업교육학회지
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• v.33 no.2
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• pp.259-272
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• 2008

In order to improve the productivity and quality of boat's mold in leisure boat industry, the development of modelling and machining technology of leisure boat's plug is strongly required. The traditional lines drawing approach by hand required the designer to both create fair curves and to make sure that the curves matched up to each other in the three main drawing views: profile, plan, and section. However, one will find when studying lines drawings in books that the curves might look smooth and fair, but the lines do not agree exactly in the three views. Therefore, the 2 dimensional drawing data of leisure boat are transformed using 3 dimensional design s/w and CAM s/w. In addition, the leisure boat is designed with a 3 dimensional s/w. The NC cutting data are generated by the CAM s/w. The surface characteristics of machined surface are investigated at various cutting conditions such as spindle speed, feed speed, and cutting material.

• Korean Journal of Computational Design and Engineering
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• v.4 no.3
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• pp.247-258
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• 1999

With the contemporary CAD/CAM system, where the tool path is generated and verified purely based on the geometric operation, geometric accuracy of the machined surface cannot be guaranteed dut to the cutting mechanics, meaning that the cutting mechanics should be incorporated in some fashion. In this paper, we incorporate the instantaneous cutting force and the tool deflection phenomena in predicting the machined surface for the finish-cut and milling operation. For the given NC dat including cutting conditions, the developed algorithm computes cutting force and deflection amount along the tool trajectory, and outputs the 3D graphic model of the machined surface together with error analysis. The validity and accuracy of the presented method has been tested by the actual cutting experiments. Experimental results and accuracy enhancement method together with implementing architecture of the VMCS (Virtual Machining CAM System) are discussed in the paper.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.7
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• pp.1227-1233
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• 2003

NURBS (Non Uniform Rational B-Spline) is widely used in CAD system and NC data for high speed machining. Conventional CAM system changes NURBS surface to tessellated meshes or Z-map model, and produces linear tool path. The linear tool path is not good fur precise machining and high speed machining. In this paper, an algorithm to change linear tool path to NURBS one was studied and the machining result of NURBS tool path was compared with that of linear tool path. The N-post including both a post-processing and a virtual machining software was developed. The N-Post transforms linear tool path to NURBS tool path and quickly shades a machined product on OpenGL view, while comparing a machined surface with a original CAD one. A virtulal machined model of original tool path and post-processed tool path was compared to original CAD model. The machining error and machining time of post-processed NURBS tool path were investigated.

• Korean Journal of Computational Design and Engineering
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• v.10 no.4
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• pp.254-261
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• 2005

The purpose of this research is to develop a method for cutting non-circular holes on a bent thick plate. Generally in order to cut the holes on the large plates, a special-purpose 5-axis machine is needed. However, such a machine is unavailable in most of the machine shops. This paper provides a description of such a method that utilizes a general-purpose 5-axis water-jet machine in place of the special-purpose machine: First, the bent piece is transformed into a flat plate, where the shape of the holes is reconstructed by considering deformation during bending. Then, after a 5-axis NC data is generated, the holes on the flat plate are cut using the 5-axis water-jet machine. The final step is to return to its, original shape by bending the plate with its newly-cut holes. The proposed methodology is implemented as a dedicated system by customizing a commercial CAD/CAM system. Some illustrations are provided throughout the paper in order to show the validity of the proposed methods and the developed system.

• Korean Journal of Computational Design and Engineering
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• v.8 no.1
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• pp.48-54
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• 2003

In a design-to-manufacturing environment, the product data is shared by various CAD/CAM/CAE systems with little integration or substantial data redundancy. The main purpose of this paper is to build a database containing all the features required for STEP-NC machining and to show how a STEP-NC repository can support the complete process for machining. A STEP-NC database schema has been constructed and several query functions have been built for the purpose of implementing the retrieving system of a STEP-NC database. The EXPRESS data model of ISO 14649 has been mapped to the database data definition language of the Oracle database. To apply the STEP-NC database to an industry example, the ISO 14649 part program has been stored into the STEP-NC database. To implement example scenarios, the sample query interface has been built.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.1
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• pp.118-125
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• 2003

As consumer's desire becomes various, agility of mold manufacturing is the most important factor for competitive mold manufacturer. Decision making process is required to produce optimal result of CAM systems in using commercial CAM system to generate tool path. The paper proposes a methodology fur computer-assisted tool selection procedures for various cutting type of rough, semi-rough and finish cuts. The procedure provides assistance for machining tool selection by analyzing sliced CAD model section of die cavity and core. Information about machining time for the generated NC-code is used to aid the tool selection. The module is developed with commercial CAM API. This module will be used fur the optimization of tool selection and planning process.