• Journal of the korean Society of Automotive Engineers
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• v.14 no.6
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• pp.113-126
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• 1992

Recently the multi-kind, small-amount manufacturing system has been replacing the mass manufacturing system, and domestic machining inustry also is eager to absorb the new technology because of its high productivity and cost reduction. The optimization of the cutting condition has been a vital problem in the machining industry, which would help increase the productivity and raise the international competitiveness. It is intended in this study to investigate the machining costs per unit time which is essential to the analysis of the optimal cutting condition, to computer the cutting speed that lead to the minimum machining costs and the maximum production to suggest the cutting speed range that enables efficient speed cutting, and to review the machining economy in relation to cutting depth and feed. Also considered are the optimal cutting speed and prodution rated in rrelation with feed. It is found that the minimum-cost cutting speed increases and the efficient cutting speed range is reduced as machining cost per unit time increases since the cutting speed for maximum production remains almost constant. The machining cost is also lowered and the production rate increases as the feed increases, and the feed should be selected to satisfy the required surface roughness. The machining cost and production rate are hardly affected by the cutting depth if the cutting speed stays below 100m/min, however, they are subject to change at larger cutting depth and the high-efficient speed range also is restricted. It can be established an adaptive optimal cutting conditions can be established in workshop by the auto-selection progam for optimal operation. It is expected that this method for choosing the optimal cutting conditions might contribute to the improvement of the productivity and reduced the cost. It is highly recommended to prepare the optimal cutting conditionthus obtained for future use in the programing of G-function of CNC machines. If proper programs that automatically select the optimal cutting conditions should be developed, it would be helpful to the works being done in the machine shops and would result in noticeable production raise and cost reduction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.2 s.233
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• pp.333-340
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• 2005

Feedrate is one of the factors that have the significant effects on the productivity, qualify and tool life in the cutting mechanism as well as cutting velocity, depth of cut and width of cut. In this study, in order to realize the high-efficient machining, a new feedrate optimization method is proposed based on the concept that the optimum feedrate can be derived from the allowable cutting power since the cutting power can be predicted from the cutting parameters as feedrate, depth of cut, width of cut, chip thickness, engagement angle, rake angle, specific cutting force and so on. Tool paths are extracted from the original NC program via the reverse post-processing process and converted into the infinitesimal tool paths via the interpolation process. And the novel NC program is reconstructed by optimizing the feedrate of infinitesimal tool paths. Especially, the fast feedrate optimization is realized by using the Boolean operation based on the Goldfeather CSG rendering algorithm, and the simulation results reveal the availability of the proposed optimization method dramatically reducing the cutting time and/or the optimization time. As a result, the proposed optimization method will go far toward improving the productivity and qualify.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.393-396
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• 2000

Spent fuel rod cutting device should cut a spent fuel rod to an optimal size in order to fast decladding operation. In this paper, for developing spent fuel rod cutting device with cutter blade, rod properties such as dimension and material of zircaloy tube and fuel pellet are investigated at first and then, various methods of existing cutting devices used commercially are investigated and their performance are analyzed and compared. This device is designed to be operated automatically via remote control system considering later use in Hot-Cell (radioactive area) and the mdularization in the structure of this device makes maintenance easy. SUS and Zircaloy-4 are selected as cut material used in the test of spent fuel rod cutting device by cutter blade. In order for constructing the high durable cutter blade, various materials are analyzed in terms of quality, shape, characteristic, and heat treatment, etc. and from these results, spent fuel rod cutting device is designed and manufactured based on the considerations of durability, round shape sustainability of rod cross-section, debris generation, and fire risk, etc.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1068-1072
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• 1997

This work deals with on investigation the influence of various additives to a base stock cutting fluid in order to develop a better deep hold drilling. This investigation has been aiming at developing an oil which gives a maximum cutting efficiency at a minimum wear rate of the tool and the guiding pads. The purpose of study is to analyze how guide pad of tools, workpiece and the change of contained quantity of extreme pressure additive in cutting fluids have effects on the hold over size of cutting hole, surface roughness of workpiece,wear rates of guide pad and roundness during the deep hole machining of SM55C with solid BTA drill by using BTA drilling system through experiment. Conclusion reached is as follows. It has been proved that the contained quantity of surphur more affects machinability than that of extreme pressure additive of chlorine of cutting fluid in BTA drilling during Deep Hole Drilling. Considering its base oil, the the contained quantity of extreme pressure assitive of surphur can be different, but it's judged that the range of 1.5 ~ 2.0% is suitable to machinability for workpiece in BTA drilling. Regarding guide pad, it's judged that the reduction of wear is possible in propotion to the contained quantity of exrreme pressure additive of chlorine against supporting of cutting force and Bumishing operation of machining parts in cutting.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.91-92
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.58-63
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• 1993

The charactistics of AE(Acoustic Emission) signal is related to cutting conditions, tool materials and tool geometry in metal cutting. The tool geometry change which is derived from tool wear affects the source of AE signal in machining process. The relationship between AE signal and tool wear was experimentally investigated. THe value of RMS(Root Mean Sequare) and Amplitude of AE signal were increased in tool wear condition. Also the high value of Count per Hit and Count vs. Frequency was observed in this condtion. As a result, tool wear can be effectively detected by AE signal during cutting operation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.262-266
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• 1993

The development of COPS(Computer aided Operation Planning System) needs data mapping paradigm which provides intelligent determonation of cutting conditions from the requirements of process planning side. We proposed the idea of multi-level mapping by the combination of heuristics of domain experts and mathematical abstraction of cutting condition and requirements. Mathematical mathods for the generalization of heuristics were constructed by multi-layer perceptron. DBMS for determination of cutting conditions was constructed by classification and combination of best fitted models. Triangular fuzzy number was used to process the uncertainties in heuristics of experts.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.1
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• pp.103-111
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• 2020

Pulling-type cutting devices, which use a diamond wire saw, have been used generally for cutting concrete structures. In this study, a pushing-type cutting device with a collection cover was developed by overcoming the disadvantages of pulling-type devices. In this device, dry or liquid methods can be selected to cool frictional heat. Operation and leakage tests of the dust generated during the dismantling of a concrete structure were carried out, confirming the suitable operation of the fabricated cutting device; the leakage rate was approximately 1.7%. For a conservative evaluation, the internal dose of workers was estimated in dismantling the core center part of biological shield concrete with a specific activity of 99.5 Bq·g^-1. The committed effective dose per worker was 0.25 mSv. The developed cutting device contributed to reducing radioactive concrete waste and minimizing worker exposure due to its easy installation. Therefore, it can be utilized as a cutting apparatus for dismantling not only reinforced concrete structures but also radioactive biological shield concrete in nuclear power plant decommissioning efforts.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.119-124
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• 1996

End milling operation is very important in machining precision components. Deterioration of surface roughness and surface geometry will cause more process for surface finishing. According to the feed rate and the cutting edge geometry, the cusp which is geometrically uncut surface is determined. To reduce the cost for dinishing operation after end milling, the cusp must be remaianed in small size as possible. Due to the cylindrical type of the end mill, tool deflection is one of the main problems in surface generation. The cutting resistance and the rigidity of the end mill will determine the size of tool deflection. One more important factor which deteriorate surface quality comes from the error in manufacturing end mills. Run-out of end mill which is the difference of the radius of each cutting edges will produce the difference of the cusp size in every rotation of end mill. These three major factors to the surface quality will be analized and the result will be compared with experimental ressult.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.547-552
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• 2003

In mold machining, there are many concave machining regions where chatter and tool deflection occur since MRR (material removal rate) increases as curvature increases even though cutting speed and depth of cut are constant. Boolean operation between stock and tool model is widely used to compute MRR in NC milling simulation. In finish cutting, the side step is reduced to about 0.3mm and tool path length is sometimes over 300m. so Boolean operation takes long computation time and includes much error if the resolution of stock and tool model is larger than the side step. In this paper, curvature of CL(cutter location) surface and side step of tool path is used to compute the feedrate for constant MRR machining. The data structure of CL surface is Z-map generated from NC tool path. The algorithm to get local curvature from discrete data was developed and applied to compute local curvature of CL surface. The side step of tool path was computed by point density map which includes cutter location point density at each grid element. The feedrate computed from curvature and side step is inserted to new tool path to regulate MRR. The resultants wire applied to feedrate optimization system which generates new tool path with feedrate from NC codes for finish cutting. The system was applied to speaker mold machining. The finishing time was reduced to 12.6%. tool wear was reduced from 2mm to 1.1mm and chatter marks and over cut on corner were removed.