• Korean Journal of Computational Design and Engineering
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• v.15 no.5
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• pp.354-361
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• 2010

The paper presents an efficient computation of optimal tool length for 5-axis mold & die machining. The implemented procedure processes an NC file as an initial input, where the NC data is generated by another commercial CAM system. A commercial CAM system generates 5-axis machining NC data which, in its own way, is optimal based on pre-defined machining condition such as tool-path pattern, tool-axis control via inclination angles, etc. The proper tool-length should also be provided. The tool-length should be as small as possible in order to enhance machinability as well as surface finish. A feasible tool-length at each NC block can be obtained by checking interference between workpiece and tool components, usually when the tool-axis is not modified at this stage for most CAM systems. Then the minimum feasible tool-length for an NC file consisting of N blocks is the maximum of N tool-length values. However, it can be noted that slight modification of tool-axis at each block may reduce the minimum feasible tool-length in mold & die machining. This approach can effectively be applied in machining feature regions such as steep wall or deep cavity. It has been implemented and is used at a molding die manufacturing company in Korea.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.5
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• pp.60-68
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• 2008

The tool overhang length affects tool deflection and chatter that should be reduced for machined surface quality, productivity and long tool lift. The shortest tool setting algorithm that uses a safe space is proposed and applied with simulation software in NC machining. The safe space in the coordinate fixed in the tool is computed by the virtual machining system that simulates NC machining by stock model, tool model and NC code. The optimal tool assembly that has largest diameter and shortest length is possible using the safe space. This algorithm has been applied over fifty companies for safe and rigid tool setting. The collision accident between holder and stock was reduced from 3 to 0 a year and the productivity was incensed about 15% by using faster feed rate acceptable for shorten tool length.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.1
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• pp.69-88
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• 2001

In the zigzag milling operation, an important issue is to design a machining strategy which minimizes the cutting time. An important variable for minimization of cutting time is the tool path length. The tool path is divided into cutting path and non-cutting path. Cutting path can be subdivided into tool path segment and step-over, and non-cutting path can be regarded as the tool retraction. We propose a new method to determine the cutting direction which minimizes the length of tool path in a convex or concave polygonal shape including islands. For the minimization of tool path length, we consider two factors such as step-over and tool retraction. Step-over is defined as the tool path length which is parallel to the boundary edges for machining area and the tool retraction is a non-cutting path for machining any remaining regions. In the determination of cutting direction, we propose a mathematical model and an algorithm which minimizes tool retraction length in complex shapes. With the proposed methods, we can generate a tool path for the minimization of cutting time in a convex or concave polygonal shapes including islands.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.2
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• pp.128-138
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• 2002

In this paper, we address how to reduce the length of tool retraction in a zigzag pocket machining. Tool retraction, in a zigzag pocket machining, is a non-cutting operation in which the tool moves to any remaining regions for machining. We developed an algorithm of generating tool retraction length in convex or concave polygonal shapes including islands. In the algorithm, we consider concave areas of cutting direction in the polygonal shape. Considering concave areas of cutting direction, the polygonal shape is decomposed to subregions which do not need any tool retraction. Using the proposed algorithm, we calculated the shortest length of tool retraction in cutting direction. Examples are shown to verify the validity of the algorithm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.201-202
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• 2009

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.2
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• pp.72-79
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• 2000

A new optimal tool design model which can be minimized the resultant cutting forces under the constrains of variables was developed. The resultant cutting forces are used as the objective function and tool angles are used as the variables. Cutting experiments of tool wear and chip length using the new and conventional tools wee carried out. Tool life of optimized cutter are more increased than those of conventional cutter by 2.29 times and 2.52 times at light and at heavy cutting conditions respectively. Chip length of optimized cutter are more increased than those of conventional cutter It is considered that the decrease of the resultant cutting forces is the cause that an effective rake and shear angles by the shape of optimal cutter.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.8-15
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• 2005

A new measuring method for tool deflection has been developed when sculptured surface is processed in ball-end milling. Since the vibration due to cutting forces has low frequencies, an electromagnetic sensor is used for measuring the exact vibration displacement. The amplitude and direction of vibration displacement during the cutting process is presented as orbital plot. In this study, it assumes that the vibration displacement is proportional to the length of cutting chip. Therefore, tool deflection is calculated by summing up the vibration displacement of unit chip length for engaged chip length. In addition, computer programs has been developed to predict the deflection of tools when machining sculptured surface. This developed program predicts the tool deflection per block of NC data, so that it can easily identify the parts which have the possibility of machining errors.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.5
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• pp.49-56
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• 1987

This paper is a study on the effect of the cutting speed on the tool wear in turning of the glass fiber reinforced plastics. The wear behavior of cutting tool is studied by means of turning, changing the cutting speed and feed in the wide range. Moreover, the theoretical model applicable to the cutting speed of wide range is analysed. The main results obtained are as follows: The relation between the tool wear and the cutting speed is divided into three range in case of the constant cutting distance. 1) At the low cutting speed, the tool wear is independent of the cutting speed, but dependent mainly on the contact length between tool and glass fiber(lst range). 2) At the high cutting speed, the tool wear is independent of the contact length, and dependent on the cutting speed only(2nd range). The tool wear increases in proportion to the cutting speed. 3) At the higher cutting speed than the speed in the 2nd range, the tool wear is independent both of the cutting speed and the contact length(3rd range). 4) In the 3rd range, tool flank wear is constant and is observed that only the wear of cutting edge increases.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.309-313
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• 2000

In order to meet the industrial requirement, precision grinding with brush tool has been applied. To analyze the brush tool characteristics, several parameters including numbers of brush string installed in a single holder, depth of cut and brush length have been changed. Several data from various source were acquired using AE, acceleration and tool dynamometer during the process. Consistent results revealing certain trend with respect to each process condition were observed.

• Design & Manufacturing
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• v.9 no.2
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• pp.16-19
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• 2015

In this paper, The experimental study on the crack during press forming of the door latch assembly for a vehicle door is performed. Length to be inserted into the conventional mold upper die punch is 20 mm, wherein the cracks are generated on the product surface and causes a secondary quality problem. In this study, the length to be inserted in the mold upper die punch 0 mm, 10 mm, 20 mm, which was changed to perform the experiment. Through the experiment, the length inserted into the mold can be seen that the upper die punch of the press forming conditions optimized when the 0 mm.