• Journal of Mechanical Science and Technology
• /
• v.17 no.2
• /
• pp.239-245
• /
• 2003

Ultra precision diamond cutting is a very efficient manufacturing method for optical parts such as HOE, Fresnel lenses, diffraction lenses, and others. During micro cutting, the rake angle is likely to become negative because the tool edge radius is considerably large compared to the sub-micrometer-order depth of cut. Depending on the ratio of the tool edge radius to the depth of cut, different micro-cutting mechanism modes appear. Therefore, the tool edge sharpness is the most important factor which affects the qualities of machined parts. That is why diamond, especially monocrystal diamond which has the sharpest edge among all other materials, is widely used in micro-cutting. The majar issue is regarding the minimum (critical) depth of cut needed to obtain continuous chips during the cutting process. In this paper, the micro machinability near the critical depth of cut is investigated in micro grooving with a diamond tool. The experimental results show the characteristics of micro-cutting in terms of cutting force ratio (Fx/Fy), chip shape, surface roughness, and surface hardening nea. the critical depth of cut.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.11 no.4
• /
• pp.75-81
• /
• 2002

In this study, experiments were carried out to investigate the characteristics of grinding and wear process of diamond wheel during grinding ceramic materials. Normal component of grinding resistance was decreasing while increase of spindle speed. The resistance of vitrified bond wheel was less then that of resinoid bond wheel because of imbedded large holes on the surface of cutting edge. Surface roughness was decreasing while increase of spindle speed. The surface roughness using vitrified bond wheel was less than that of resinoid bond wheel because of small elastic deformation. After continuous finding of ceramics, cutting edge ratio of resinoid bond wheel decreased. For the case of vitrified bond wheel, cutting edge ratio did not change.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.12 no.3
• /
• pp.89-95
• /
• 2003

This research analyzes the cutting mechanism of A1100-H18 of commercially pure aluminum by image processing in SEM(Scanning Electron Microscope) for the measurement of strain rate distribution near a cutting edge in orthogonal micro-cutting. The distribution is measured using various methods in order. The methods are in-situ observations of cutting process in SEM, inputting image data, a computer image processing, calculating displacements by SSDA(Sequential Similarity Detection Algorithm) and calculating strain rates by FEM. The min results obtained are as follows: (1)It enables to measure a microscopic displacement near a cutting edge. (2) An application of this system to cutting process of various materials will help to make cutting mechanism clear.

• Design & Manufacturing
• /
• v.17 no.1
• /
• pp.33-39
• /
• 2023

The ball end mill is a type of cutting tool that is widely used to process complex mold shapes including aspheric surfaces. Unlike the flat end mill in which the cutting edge is formed on the cylindrical handle, the cutting edge is formed from the cylindrical handle to the hemispherical shape, which is advantageous for processing curved shapes. However, since the cutting speed continuously changes during machining due to the helix angle of the cutting edge or the machining inclination angle, it is difficult to obtain a precise machined surface. Therefore, in this paper, machining was performed while changing the helix angle of the ball end mill and the angle of the machining slope under the same cutting conditions for STD 11 material, which is widely used as a mold material. Through this, the effect of the two variables on the roughness of the machined surface was analyzed. As a result, if the helix angle was 0 degrees, it showed the best surface roughness of Ra. 0.16 ㎛. When the helix angle was 20 degrees, the best surface roughness of Ra. 0.18 ㎛ was occurred.

• The Journal of the Convergence on Culture Technology
• /
• v.10 no.1
• /
• pp.227-233
• /
• 2024

Korea achieved its highest ever defense export performance in 2022. Defense exports are the most effective way to promote the defense industry by exporting Korea's weapons to foreign countries. In addition, to continuously supply excellent weapon systems, a solid defense industry must be established. So defense industry exports are an important issue at the national level, the Korea government is actively supporting policies for the Presidential office as a control tower. In particular, the topic of entry into the defense industry export big4 is being raised in Korea. As an innovative defense export promotion plan, this paper presents a strategic plan of joint research and development that export customized to the needs of purchasing countries and securing cutting-edge technology that can possess world-class weapon systems. In other words, in order to secure cutting-edge technology, the military must break away from existing methods and boldly select cutting-edge technology, provide sufficient budget support, and grant autonomy to development agencies. A rapid acquisition system must also be introduced so that this technology can be applied to advanced weapons in a timely manner. Export joint research and development is intended to promote flexible technology transfer excluding ultra-sensitive core technologies and to form strategic partnerships, taking into account the purchasing country's willingness to possess cutting-edge technology. Through this, we have helped Korea's defense industry exports enter the world's big4 through groundbreaking new strategy.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.8 no.5
• /
• pp.102-107
• /
• 1999

In this paper hardened SCM440 material and annealed SCM440 material are for cutting experiments by the cutting con-dition which is chosen respectively by tool three components of cutting force are recorded using multicorder, Then the surface roughness for various force are measured by Roughness Tester. The results of the experiment are summarized as follow. The hardened material cut by ceramic tool(BX20) gives the highest radial component values among the cutting resistance radial components is increased higher for the higher cutting speed even though vertical component and axial component tend to decrease. But when the annealed material was cut increase in cutting speed results in the increase of three component forces. Since ceramic insert tip used the experiment hardly affect Built-up Edge and heat the cutting resistance decrease slightly regardless of the increased of cutting speed. The hardened material has higher three compo-nent force value than the annealed material because the material of high hardness is increased cutting resistance. The low-est cutting forces for hardened material and annealed material are shown in the cutting speed of 60m/min and 180m/min. respectively.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2001.10a
• /
• pp.393-398
• /
• 2001

The technique of high speed machining is widely studied in machining fields, because the high efficiency and accuracy in machining can be obtained in high speed machining. Unfortunately the development of tool for high speed machining in not close behind that of machine tool. In this study, several types flat endmill is prepared for obtaining data according to tool shape. Especially, we concentrated in helix angle, number of cutting edge, rake angle and relief angle. Machinability is measured by cutting force, tool life, tool wear, chip shape and surface roughness according to cutting length. 3-axis cutting forces are acquired from the invented tool dynamometer for high speed machining. Particularly, we found out that the axial cutting force waveform has a good relation with tool wear features. By above results, it is suggested the endmill tool with $45^{\circ}$ helix angle, 6 cutting edge, $-15^{\circ}$ rake angle and $12^{\circ}$ relief angle be suitable for high speed machining

• Journal of Advanced Marine Engineering and Technology
• /
• v.25 no.1
• /
• pp.171-181
• /
• 2001

Recently, the development of CNC machine tools seems to bring about progressional high speed, precision and automation in cutting processing, but is unlikely to avoid the generation of burr arising from plastic deformation, which may result in deterioration of improvement in the precision and productivty of products. In this study, Experiment has been carried out to prevent and decrease the grinding burr under various working conditions ; working speed, side cutting edge, back rake angle, disengage angel.

• ETRI Journal
• /
• v.34 no.4
• /
• pp.602-612
• /
• 2012

It is becoming increasingly difficult to identify promising technologies due to the influx of new technologies and the high level of complexity involved in many of these technologies. Identifying promising information and communications technology (ICT)-based converging technologies holds the key to finding new sources of economic growth and forward momentum. The goal of this study is to identify cutting-edge ICT-based converging technologies by examining the latest trends in the US patent market. Analyzing the US patent market, the most competitive of such markets in the world, can yield certain clues about which of the ICT-based converging technologies may be the next revolutionary technologies. For a classification of these technologies, this study follows the International Patent Classification system. As for ICT, there are 58 related fields at the subclass level and 831 fields at the main-group level. For emerging and converging technologies, there are 75 at the main-group level. From these technologies, a final selection for cutting-edge ICT-based converging technologies is made using a composite index reflecting the converging coefficient, emerging coefficient, and technology impact index.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2006.10a
• /
• pp.21-22
• /
• 2006