• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.422-428
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• 2001

The term High Speed Machining has been used for many years to describe end milling with small diameter tools at high rotational speeds, typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry for the machining of light alloys, notably aluminium. In recent year, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. With increasing cutting speed used in modern machining operation, the thermal aspects of cutting become more and more important. It not only directly influences in rate of tool wear, but also will affect machining precision recognized as thermal expansion and the roughness of the surface finish. Hence, one needs to accurately evaluate the rate of cutting heat generation and temperature distributions on the machining surface. To overcome the heat generation, we used to cutting fluid. Cutting fluid play a roles in metal cutting process. Mechanically coupled effectiveness of cutting fluids affect to friction coefficient at tool-work-piece interface and cutting temperature and chip control, surface finish, tool wear and form accuracy. Through this study, we examined the behavior of heat generation in high-speed machining and the cooling performance of various cooling methods.

• Korean Journal of Plant Resources
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• v.36 no.4
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• pp.390-401
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• 2023

The purpose of this study was to identify the propagation characteristics of Diabelia spathulata (Siebold & Zucc.) Landrein through seeding and cutting methods. The seed germination rate was meager (0.22~3.56%). In hardwood cutting, the highest rooting rate was 36.1% in sand + perlite (2:1) and 37.8% in 1000 PPM of IBA pre-treatment. Softwood cutting showed the highest rooting rate when the cutting diameter was 3 to 5 mm and the cutting length was 7 to 8 cm. In particular, the highest rooting rate of 80% was observed in the sand among the 8 cultivation media treatments. In the case of root cuttings, the rooting rate was 83.3~96.7% in all cultivation media. The highest rooting rate was observed when the diameter of the cutting was 7 to 8 mm, and the length of the cutting was about 10 to 11 cm. Among cutting methods, root cutting showed the highest rooting rate. Division showed a 100% rooting rate regardless of size or growth status. For Diabelia spathulata (Siebold & Zucc.) Landrein, propagation by cuttings was more efficient than seeding. However, Further research on the morphophysiological dormancy and dormancy break of seeds is needed for seed propagation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.06a
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• pp.19-27
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• 2000

High speed machining (HSM), specifically end milling and ball end cutting, is attracting interest in the die/mold or aerospace industries for the machining of complex 3D surfaces. HSM of difficult-to-cut materials such as die/mold steels, titanium alloys or nickel based superalloys generates the concentrated thermal/frictional damage at the cutting edge of the tool and rapidly decreases the tool life. Following a brief introduction on HSM and reated aerospace or die/mold work, the paper reviews published data on the effect of cutter/workpiece orientation and cutting environments on tool performance. First, experimental work is detailed on the effect of cutter orientation on tool life, cutting forces, chip formation, specific force and workpiece surface roughness. Cutting was performed using 8 mm diameter PVD coated solid carbide cutters with the workpiece mounted at an angle of 45 degree from the cutter axis. A horizontal downwards cutting orientation proveded the best tool life with cut lengths ∼50% longer than for all other directions (horizontal upwards, vertical downwards, vertical upwards). Second, the cutting environments were investigated for dry, flood coolant, and compressed chilly air coolant cutting. The experiments were performed for various hardened materials and various coated tools. The results show that the cutting environment using compressed cilly air coolant provided better tool life than the flood coolant or the dry.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.223-227
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• 2013

Dust collecting performance of cyclone collector for oil mist was alalyzed in the study. The purposes of using cutting fluid during cutting have been colling, lubricating, chip washing and anti-corroding. However, the present manufactaring industry restricts the use of cutting fluid because cutting fluid confains poisonous substances which are harmful to the human body. Also, the optimum design oil-mist collector. The new oil mist collector was designed. In the near future, this device must be tested in the real machining center and CNC machine. Cutting using oil-mist showed better cutting characteristics than dry, air and fluid cutting with respect to by cutting force, tool wear and surface roughness. The model(A, B Type cyclone) of the set of fixture and alveolus are made by using a CAE software. Finally, we have obtained a model A Type solution by using orthogonal array. Therefore, it could be confirmed that as the model-A was increased and model-B was decreased, cut diameter was decreased.

• 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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.4
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• pp.33-39
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• 2003

The stiffness of multi-articulated industrial robots is very weak, because their structure is an articulated type with some links and joints. Thus it is known that cutting processes for metals are not accepted in machine shop well, but they have a lot of merits for cutting processes, for example, drilling, tapping, and engraving etc, because of the characteristics of their high degree of freedom. The temptation of cutting aluminium was carried out to investigate the feasibility and the limitations or constraints for cutting metals on them. First the mode shapes of 6 degree of freedom welding robot were taken and analysed, and next the cutting processes were practically carried out on it. The results of study were found out to show the feasibility of cutting processes at drilling under 6mm of tool diameter, as well as to have some limitations and constraints, for examples, feed rate, depth of cut and cutting force etc.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.1
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• pp.70-77
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• 2015

This paper develops and evaluates a mechanical machining process which involves drilling on PVS material. According to the material, two treatment experiments were conducted, one involving drilling in a wet condition or using a lubricant and one involving drilling in a dry condition with no lubricant. Drilling in a dry condition showed better performance in terms of the cutting time than in the wet condition. Otherwise, the wet condition has several advantages. The lubricant influenced the burr diameter size and minimized the temperature on the surface of the work piece. During the wet condition drilling process, a smaller burr diameter size was noted as compared to the dry condition. The temperature showed a linear correlation with the drill bit size, where a least-square analysis provided an $R^2$valuewhichexceeded 0.95. The wet condition required more cutting time than the dry condition. In this condition, the water provides a lubrication effect. A thin layer between the cutting edges and the surface of the work piece is formed. The chip formation is affected by the drilling depth. The color on the tips of the chips was darker than in the initial condition. No correlation between the drilling depth and the bore roughness was noted, but the variation of the cutting speed or the RPM influenced the roughness of the bore. The optimum cutting speed ranged from 40 RPM to 45 RPM in the condition which provided the finest roughness surface.

• Journal of the Korean GEO-environmental Society
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• v.9 no.3
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• pp.29-34
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• 2008

A large diameter sampler was developed to take undisturbed samples from not only soft ground but also sandy and weathered ground. The large diameter sampler which was developed in Korea Institute of Construction Technology(KICT-type large diameter sampler) was manufactured based on the principle of triple core barrel sampling. A specially designed cutting device was used to cut and contain various kinds of samples in the sampler during a sampling and retrieval procedure. By adjusting the stiffness of the spring located at the top of the sampler, the distance between the cutting shoe and auger can be controlled in accordance with the ground condition. In order to investigate the applicability of the developed sampler and compare the quality of the samples taken by the sampler with that by the traditional thin-walled tube sampler, samples were taken at various sites according to the ground condition. And a series of laboratory tests such as the unconfined compress ion test, triaxial compression test, oedometer test, large diameter Rowe cell consolidation test (D: 150 mm) were performed. The test results showed that the samples by the KICT-type large diameter sampler show higher quality than the samples by the thin-walled tube sampler. And the validity and applicability of the developed KICT-type large diameter sampler was confirmed accordingly.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.4
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• pp.325-330
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• 2004

The forces acting on the tool are an important aspect of maching. For those concerned with the manufacture of machine tools, a knowledge of the forces in needed for estimation of power reguirements and for the design of machine tool elements tool-holders and fixtures, adequately rigid and free from vibration. The force reguired to form the chip is dependent on the shear yield strength of the work material un der cutting conditions which are cutting speed, workpiece, feedrate, insert type. In this study, FG, ML, MP, MC, C, RT inserts were investigated in turning using SM45C, SCM4, SKD11, SUS316, materials. The diameter of materials was 60mm, 80mm, 110mm. This paper presents MP were lowest and SKD11 were largest of the workpiece in cutting forces.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.43-49
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• 2004

The objective of this research is to investigate the effect of clearance angle on cutting performance in high speed end milling operation. The tool geometry parameters have complex relationship with cutting process parameter. In order to explain the effect of clearance angle, 2D turning operation in lathe and end milling operations are performed. Tools with different clearance angles are manufactured. Cutting forces, machining accuracy and tool life are examined according to the change of clearance angle. As clearance angle increases, cutting force decreases and machining accuracy improves. But it has been proved that there exists the optimal clearance angle according to the diameter of end mill for maximum tool life which is measured by frank wear.