• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.84-90
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• 1999

The finishing process for dies and molds is directly related to finished surface quality, but many parts of process depend on human labor which needs much time and value. So automatic finishing machine has been produced for dies and molds, and applied widely for finishing process. Conventionally finishing machine has applied resin bonded finishing pad as a tool, but the removal ability of pad decreases greatly as finishing process goes on. In the finishing mechanism for dies and molds, finishing process is affected severely by cutting process, so can be divided into removing cusp and smoothing surface process. So, this study investigated the application of cast iron bonded diamond pellet for press dies, which is considered to have better characteristics than the other metal bonded pellets. The finishing characteristics were compared the between finishing pellet and pad. And finishing performance was appraised as the several cutting surfaces.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.5
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• pp.413-420
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• 2014

Although the transfer forming process has various advantages, it is also inefficient for the use of multiple press machines, especially for small part sizes. In this study, a new forming process was proposed to use multiple tandem dies in a single press machine. A rotary transfer forming device was developed to combine the advantages of the progressive and transfer forming process. In this study, a detailed forming process using this device was analyzed, and the device was designed to perform four series of tandem forming processes in a single press. In order to analyze the feasibility of this forming process, simple forming dies were made. As a result, the position accuracy was 4 arcsec, and the forming speed reached up to 20 strokes per minute. It is thought that this rotary transfer forming device can help to save initial setup costs through the more efficient use of space in a press machine.

• Transactions of Materials Processing
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• v.25 no.4
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• pp.242-247
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• 2016

CFD simulation with FlowVision^® is used to evaluate the capability of cooling channel in hot press forming dies. Two different types of cooling channels, dry drilled and pocket types are considered for comparison. Two different approaches for simulating cooling channel are considered. One is single-phase velocity calculation for coolant only and the other is multiphase thermal and velocity calculation for die, blank and coolant all together. Both approaches show better cooling performance in pocket type cooling channel. Also both approaches show their own effectiveness in designing cooling channel of hot press forming dies.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.63-73
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• 2001

This paper presents a process and operation planning system with an NC code post-processor for effective machining of press dies for production of cars. Based on the machining features, 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 we developed adjusts feedrates along the tool path to reduce machining time. The adjustment rule is selected based on the metal removal rate estimated by virtually machining with virtual cutting tool.

• Korean Journal of Computational Design and Engineering
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• v.9 no.4
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• pp.373-381
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• 2004

Using standard components of a press die is recognized as a way for a cost reduction and a short lead time. It also provides a way for a quick maintenance of a die under repair. It is expected to contribute to integration of CAD/CAM system for manufacturing dies in the future. This paper presents a 3D CAD library which is constructed using the standard components and is used for designing a press die. This 3D CAD library is generated by a database system made of Microsoft Access for standard components and by CATIA V5 R10 API for geometric features. The library is implemented using Visual Basic 6.0 utility of CATIA API function in the Windows NT environment. It creates a 3D model of the standard components of press die easily when a die designer inputs numerical values of geometric features and the BOM of the completely assembled parts. It also generates automatically the assembly drawing of die set by using variables for standard values of die parts. Therefore users can save the cost of time to design the press die components, and even a beginner can use this program with ease. The test results of the 3D CAD library for designing shearing and bending dies verify its usefulness and feasibility.

• Journal of the Optical Society of Korea
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• v.11 no.3
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• pp.85-92
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• 2007

In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric glass lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical glass molding pressing (GMP) process was developed with an eye to mass production of precision optical glass parts by molding press. In this paper, as a fundamental research to develop the multi-cavity mold for higher productivity of a progressive GMP process used in the fabrication of an aspheric glass lens, an aspheric glass lens forming simulation was carried out.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.12
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• pp.125-131
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• 2008

In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical GMP processes were developed with an eye to mass production of precision optical glass parts by molding press. Generally because the forming stage in a GMP process is operated at high temperature above $570^{\circ}C$, thermal stresses and deformations are generated in the aspheric glass lens mold that is used in GMP process. Thermal stresses and deformations have negative influences on the quality of a glass lens and mold, especially the height of the deformed glass lens will be different from the height of designed glass lens. To prevent the problems of a glass lens mold and the glass lens, it is very important that the thermal stresses and deformations of a glass lens mold at high forming temperature are considered at the glass molds design step. In this study as a fundamental study to develop the molds used in an aspheric glass lens fabrication, a heat transfer and a thermal stress analysis were carried out for the case of one cavity glass lens mold used in progressive GMP process. Finally using analysis results, it was predicted the height of thermally deformed guide ring and calculated the height of the guide ring to be modified, $64.5{\mu}m$. This result was referred to design the glass lens molds for GMP process in production field.

• Transactions of Materials Processing
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• v.23 no.2
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• pp.75-81
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• 2014

Progressive dies are used for metal stamping during which multiple operations are performed in a sequence. Material is fed automatically from a coil into the press and advances from one die station to the next with each press stroke. Transfer dies are used in high-volume manufacturing for round, deep-drawn, and medium-to-large parts. Several different operations may be incorporated within a transfer die such as blanking, bending, piercing, trimming, and deep drawing. The main challenge in the current study is how to deform a seat cushion panel meeting the design specifications without any defects. A complex automation die manufacturing technology for the automotive seat cushion panel, mixing both semi-progressive die and transfer die for continuous production, was developed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.19-25
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• 2002

Profile machining using cutter diameter compensation is widely used in die and mould manufacturing. Especially automotive die makers try to use 3D-profile machining for trimming or flange dies. But the technological requirements and implementation issues haven't been defined. In this paper we summarized the requirements and issues of 3D-profile machining. Approximation of input profiles into sequences of line and helical arc is the first major issue. The second major issue is removing cutter interference from the approximated curves holding z-values when the maximum cutter diameter is given. Keeping constant machining width, local machining, path linking problems and several detail technological requirements are also discussed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.3
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• pp.85-91
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• 1998

In this paper an assessment has been proceeded about component technology that stamping car panel can be designed and manufactured efficiently. Also this study investigate standard model of CAD/CAM system in production process of automobile dies, Recently, motor companies are doing their best to increase productivity and to reduce production time. So to develop user-friendly and effective standard model of CAD/CAM system is very important. The cbtained results will lead to the reductions in lead time and man-hour required for the design and manufacture of the automobile dies.