• 산업공학
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• 제18권3호
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• pp.247-252
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• 2005

In the automated production environment in the present days, the minimization of manual operation becomes a very important factor in increasing the efficiency of the production system. The exit burr produced through the milling operation on the edge of workpiece usually requires manual deburring process to enhance the level of precision of the resulting product. So far, researchers have developed various methods to understand the formation of exit burr in cutting process. One method to analytically identify the formation of exit burr was to use the geometrical information of CAD and CAM data used in automated machining. This method, in turn, generated the information resulting from the analysis such as burr type, cutting region, and exit angle. Up to now, the geometrical data were restricted to the single feature and single path. In this paper, a method to deal with the complicated geometric features such as line segment, arc, hole, and spline will be presented and validated using the field data. This method also deals with the complex workpiece shape which is a combination of multiple features. As for the cutting path, multiple tool path is analyzed in order to simulate the real cutting process. All this analysis is combined into a Windows based software and real data are used to validate the program in the conclusion.

• 한국기계가공학회지
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• 제17권4호
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• pp.1-8
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• 2018

In drilling Inconel 601, which is used for compressor cases in aircraft engines, a lot of cutting oil must be supplied. This prevents tools from wear and fracture due to the heat buildup resulting from the high-temperature resistance and toughness of this alloy. However, the cutting oil supply has compromised the machining environment. This has caused attention to shift to an environmentally friendly cutting fluid supply system called the Minimum Quantity Lubrication(MQL) system. The aim of this study was to find a more efficient drill processing method using MQL and to verify its performance. To that end, the properties of Inconel that make it difficult -to -drill were studied by a comparison with the drilling of SM45C. Specific factors (i.e., cutting force and tool wear) were examined in relation to the conditions in the MQL-based drilling system. Based on these results, a sealed cover and step feed were proposed as measures to increase the effectiveness of the MQL system. The efficiency of the proposed method was established.

• 한국정밀공학회지
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• 제18권2호
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• pp.161-170
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• 2001

Synthetic water-based metal-cutting fluids are increasingly popular in the metal-working industry because of its environmental friendliness. The propose of this study is to investigate the synergistic effect of combining polyethylene glycol and common fatty acid in formulating a metal-cutting fluid. The tested metals were aluminum, copper and steel, and the test was performed with a modified drilling machine. From the study, it was found that there existed some synergistic effects on the drilling efficiency of the metals to decrease of cutting time, cutting energy, torque as well as the smoothness of surface depended on the formulation ratio of the two fluids.

• 패션비즈니스
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• 제19권5호
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• pp.199-212
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• 2015

Environmentally-friendly whole-cut designs can minimize carbon dioxide emissions which are harmful to the earth, and reduce energy, labor force and time in cutting or sewing clothes. The design and way of wearing clothing will be investigated by classifying whole-cut clothing appearing in the history of costume and past traditional outfits such as Drapery, a Pancho, Tunic, or Loincloth. According to the results from the analysis of whole-cut methods applied in design, they were classified as follows: whole-cut, utilizing square-panels as is, pleats, smoking, lip band, origami, cutting way, and subtraction-cutting whole-cut design. The whole-cut design utilizing square panel as it is can minimize the waste of energy and material but can also maximize the possibility of circulation by recycling. In utilizing an all square panel, it broke away from the existing whole-cut in the western pattern, namely, the pattern of clothes clinging to the body, and was found to have new aesthetic value with a new approach. Due to the whole-cut method having a restriction in the use of dart and line cutting in its designing process, there were only designs that did not show the body line, such as designs clinging to the body. Therefore we developed a design similar to those that cling to the body by whole-cut, In addition, the work produced was with high efficiency and variability, which produces simple designs but can be worn in a variety of ways.

• Smart Structures and Systems
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• 제24권3호
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• pp.345-360
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• 2019

The shear keys are set in a seismic isolation system to resist the long-term service loadings, and are cut off to isolate the earthquakes. This paper investigated the influence of shear keys on the seismic performance of a vertical spring-viscous damper-concave Coulomb friction isolation system by an incremental dynamic analysis (IDA) and a performance-based assessment. Results show that the cutting off process of shear keys should be simulated in a numerical analysis to accurately predict the seismic responses of isolation system. Ignoring the cutting off process of shear keys usually leads to untrue seismic responses in a numerical analysis, and many of them are unsafe for the design of isolated structure. And those errors will be increased by increasing the cutting off force of shear keys and decreasing the spring constant of shear keys, especially under a feeble earthquake. The viscous damping action postpones the cutting off time of shear keys during earthquakes, and reduces the seismic isolation efficiency. However, this point can be improved by increasing the spring constant of shear keys.

• 한국기계가공학회지
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• 제21권6호
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• pp.81-88
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• 2022

Titanium alloy (Ti-6Al-4V) has excellent mechanical properties and high specific strength; therefore, it is widely used in aerospace, automobile, defense, engine parts, and bio fields. Particularly in the aerospace field, as it has a low specific gravity and rigidity, it is used for the purpose of increasing energy efficiency through weight reduction of parts, and most have a thin-walled structure. However, it is extremely difficult to machine thin-walled shapes owing to vibration and deformation. In the case of thin-walled structures, the cutting forces and vibrations rapidly increase depending on the cutting conditions, significantly affecting the surface integrity and tool life. In this study, machining experiments on thin-wall milling of a titanium alloy (Ti-6Al-4V) were conducted for each experimental condition with different axial depths of cut, radial depth of cut, and machining sequence. The machining characteristics were analyzed, and an effective machining method was derived by a comprehensive analysis of the machined surface conditions and cutting signals.

• 한국태양에너지학회 논문집
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• 제39권4호
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• pp.1-9
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• 2019

Modules using 6 inch cells have problems with loss due to empty space between cells. To solve this problem made by shingled structure which can generate more power by utilizing empty space by increasing the voltage level than modules made in 6inch cell. Thus, in this paper, the c-Si cutting cells were produced using nanosecond green laser, and then the ECA was sprayed and cured to perform cutting cell bonding. Three types of ECA materials (B1, B2, B3) with Ag as the main component were used, and experimental conditions varied from 5 to 120 seconds of curing time, 130 to $210^{\circ}C$ of curing temperature, and 1 to 3 of curing numbers. As a results of experiments varying curing time, B1 showed efficiency 19.88% in condition of 60 seconds, B2 showed efficiency 20.15% in 90 seconds, and B3 showed efficiency 20.27% in 60 seconds. In addition, experiments with varying curing temperature, It was confirmed highest efficiency that 20.04% in condition of $170^{\circ}C$ with B1, 20.15% in condition of $150^{\circ}C$ with B2, 20.27% in condition of $150^{\circ}C$ with B3. These are because the Ag particles are densely formed on the surface to make the conduction path. After optimizing the conditions of temperature and curing time, the secondary-tertiary curing experiments were carried out. as the structural analysis, conditions of secondary-tertiary curing showed cracks that due to damp heat aging. As a result, it was found that the ECA B3 had the highest efficiency of 20.27% in condition of 60 seconds of curing time, $150^{\circ}C$ of curing temperature, and single number of curing, and that it was suitable for the manufacture of Solar cell of shingled structure rather than ECA B1 and B2 materials.

• 한국유기농업학회지
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• 제9권1호
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• pp.37-49
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• 2001

This experiment was carried out to investigate the effects of application levels of nightsoil sludge compost(NSC) in 3 and 4 cuttings per annum on the dry matter yields and nutritive value of orchardgrass(Dactylis glomerata L.). Annual nightsoil sludge compost(NSC) were applied at levels of 0, 10, 20, 40 and 80 ton $㏊^{respectively}$ . Relative yields of each cut to annual dry matter yield were 29.9%, 46.% and 23.2% for 1st cut, 2nd cut and 3rd cut in 3 cutting system, 23.7%, 29.3%, 34.0% and 13.0% for 1st cut, 2nd cut, 3rd cut and 4th cut in 4 cutting system, respectively. Significantly higher dry matter yield of orchardgrass obtained were 8.11 ton $㏊^{-1}$ at level of 40 ton ㏊$^{-1}$ $yr^{-1}$ in 3 cutting systems, ranges of 7.50~10.71 ton $㏊^{-1}$ at level of 10~80 ton ㏊$^{-1}$ $yr^{-1}$ in 4 cutting systems than those of non application level of NSC, respectively(p〈0.05). The mean efficiency of dry matter production to application of NSC(kg DM/ton NSC) were 46 and 102 kg in 3 and 4 cutting systems, respectively. Although th contents of crude protein(CP, %) of orchardgrass were significantly higher at the application levels of 10~80 ton $㏊^{-1}$ $yr^{-1}$ -1/ by NSC than those of the application levels at the 0 ton $㏊^{-1}$ $yr^{-1}$ in 3 and 4 cutting systems(p〈0.05), the contents of neutral detergent fiber(NDF, %) and acid detergent fiber(ADF, %) were lower in NSC plots than those at the non-application plots of NSC. The contents of total digestible nutrient(TDN, %) and relative feed value(RFV) of orchardgrass were significantly increased with increase the applicaton levels of NSC(p〈0.05).

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1223-1227
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• 2005

Fine microgroove is the key component to fabricate micro-grating, micro-grating lens and so on. Conventional groove fabrication methods such as etching and lithography have some problems in efficiency and surface integrity. This study deals with the creation of ultra-precision micro grooves using non-rotational diamond tool and CNC machining center. The shaping type machining method proposed in the study allows to produce V-shaped grooves of $40\mu{m}$ in depth with enough dimensional accuracy and surface. For the analysis of machining characteristics in micro V-grooving, three components of cutting forces and AE signal are measured and processed. Experimental results showed that large amplitude of cutting forces and AE appeared at the beginning of every cutting path, and cutting forces had a linear relation with the cross-sectional area of uncut chip thickness. From the results of this study, proposed micro V-grooving technique could be successfully applied to forming the precise optical parts like prism patterns on light guide panel of TFT-LCD.

• 한국표면공학회지
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• 제41권6호
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• pp.335-340
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• 2008

Cutting performance and wear behavior were studied with the diamond micro-blade of Cu/Sn bond materials containing various amount of lubricant materials such as graphite and $MoS_2$. Measurement of instantaneous electric power consumption for cutting glass workpiece at the constant velocity was conducted and proposed as a method to assess cutting efficiency. The energy consumption of micro-blade for glass cutting decreased with the content of graphite and $MoS_2$ while wear amount of blade in volume increased with the amount of lubricant addition during the dicing test. It is because that hardness, flexural strength, and fracture toughness ($K_{IC}$) reduced with the amount of lubricant addition. Blades with $MoS_2$ additive showed higher mechanical properties than those with graphite additives when the same amount of the lubricant additive in wt.% was added. Due to the lower density of graphite than $MoS_2$, higher volume fraction of graphite could result in stronger effect on lowering electric power consumption by reducing the friction between blade and work piece however increasing wear rate due to the reduction in strength and fracture toughness. Adhesive wearing mode of micro blade could be remarkably improved by the addition of graphite as well as $MoS_2$.