• Journal of the Korean Society of Industry Convergence
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• v.8 no.1
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• pp.31-36
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• 2005

The purpose of this experimental study is to gain equations for the prediction of surface roughness depending on the three major parameters(the cutting speed, the feed rate and the nose radius). It is the merit of Response Surface Methodology that the test time is reduced to minimum size and accurate analysis can be done. On this study, first, made specimen, Al 5052 BE material which is widely used in school and cut the specimen with coated tungsten carbide tools, by varying the cutting conditions, such as the cutting speed, the feed rate and the nose radius. In conclusion, the surface roughness was most greatly influenced by the feed rate. And Surface Roughness equation gained by experiment is as followed $$R=58.2\;v^{-0.22}f^{1.7}r^{-0.66}$$.

• Korea-Australia Rheology Journal
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• v.19 no.3
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• pp.171-176
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• 2007

LCD-BLU (Liquid Crystal Display-Back Light Unit) of medium size is usually manufactured by forming numerous dots with $50{\sim}300\;{\mu}m$ in diameter by etching process and V-grove shape with $50\;{\mu}m$ in height by mechanical cutting process. However, the surface of the etched dots is very rough due to the characteristics of the etching process and V-cutting needs rather high cost. Instead of existing optical pattern made by etching and mechanical cutting, 3-dimensional continuous micro-lens of $200\;{\mu}m$ in diameter was applied in the present study. The continuous micro-lens pattern fabricated by modified LIGA with thermal reflow process was tested to this new optical design of LGP. The manufacturing process using LIGA-reflow is made up of three stages as follows: (i) the stage of lithography, (ii) the stage of thermal reflow process and (iii) the stage of electroplating. The continuous micro-lens patterned LGP was fabricated with injection molding and its test results showed the possibility of commercial use in the future.

• Culinary science and hospitality research
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• v.12 no.4 s.31
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• pp.299-319
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• 2006

The purpose of this study was to investigate the changes of hardness and microstructure of Dongchimi cooked with various sources of sugar(xylitol, xylose, sugar, pear juice). It was fermented at $10^{\circ}C$ for 60 days. The changes of pH in Dongchimi used different kinds of sugar decreased in all samples during the fermentation period, and then showed a slow decrease after 12 days of fermentation. The total acidity of Dongchimi using xylitol arrived slowly at the best tasting condition($0.3\sim0.4$ point) compared with other conditions. The changes of salt content were showed high as compared with other test conditions in 0 day, the day of fermentation. At the early stage of fermentation, the changes of turbidity of Dongchimi using sugar, pear juice were showed high as compared with those of Dongchimi using xylitol, xylose for $5\sim15$ days of fermentation. The maximum cutting force of Chinese radish Dongchimi showed the highest value among al at the 25 th day of ripening and then decreased gradually. The maximum cutting force of Dongchimi using sugar showed the lowest. The calcium and magnesium contents of Dongchimi juice and Chinese radish Dongchimi juice using xylitol were observed high at the early stage of fermentation and showed the highest value during the fermentation period. The microstructure showed disintegration appearance of middle lamella and cell wall during the fermentation period.

• Journal of the Korean Society of Safety
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• v.24 no.1
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• pp.1-6
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• 2009

In machining of ceramic materials, they are very difficult-to cut materials because of there high strength and hardness. Machining of ceramics are characterized by cracking and brittle fracture. Generally, ceramics are machined using conventional method such as grinding and polishing. However these processes are generally costly and have low MRR(material removal rate). This paper focuses on machinability evaluation of machinable ceramics for products with CNC machining center. Thus, in this paper, experiment applying cutting parameters is performed based on experimental design method. A design and analysis of experiments is conducted to study the effects of these parameters on the surface roughness by using the S/N ratio, analysis of ANOVA, and F-test. And multiple linear regression analysis is applied to compare experimental with predicted data in consideration of surface roughness. Cutting parameters, namely, feed, cutting speed and depth of cut are used to accomplish purpose of this paper. Required experiments are performed, and the results are investigated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.127-128
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• 2009

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.292-300
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• 2007

Not many types of roughage cutters have been introduced in Korea so far. However, those machines could not satisfy farmers to cut rice straw or barley wrap-silage properly. Stiffness and firmness of roughage bale were two obstructing factors. In order to solve this problem, a tractor attached cut-feeding machinery for the round baled roughage was developed for dairy and beef cattle farm in Korea. A series of tests were performed and acquired data were analyzed by using the several imported roughage cutters, which have been already introduced in dairy farm in Korea. And, a prototype of forage cutter was selected, analyzed, designed and manufactured to develop a tractor attached roughage cut-feeder for round bale. Also, the prototype machine was tested, modified and improved through revising model. As a result, a tractor attached roughage cut-feeder for round bale was manufactured. In order to evaluate the performance of the model machinery. a series of test were performed by the prototype machinery both at the plant and field. The model machinery developed satisfied in both power requirement and cutting capacity. As a conclusion, one of the obstacles against feeding the round baled roughage in the korea cattle farm can be eliminated by developing the tractor attached round baled roughage cut-feeder.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.451-458
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• 2001

The purpose of this study was to evaluate shear parameters on cutting slope of weathered granite soils by using small dynamic cone penetration test on the very moment of its cutting. The results were : On the relations among N$\_$c/, Li, and CEC, the condition of Li＞6%, CEC＞14(meq/100g) corresponds to that of N$\_$c/ values of 2∼30, and 3＜CEC＜14(meq/100g) to N$\_$c/=30∼50. Comparing the smallest penetration depth from two small dynamic cone penetration tests done at 5m below from the top of the slope on April 15th, October 31t. there was a l0cm difference. So we could find out the degree of weathering on the slope. And dividing the difference by 190 days (the whole testing time), we could know it's being weathered 0.052mm each day. The more N. value increases, the more shear parameters(internal friction angle ; $\phi$, cohesion : c) increase at a standard pressure($\sigma$＞32㎪). So the condition of N$\_$c/=2∼50 corresponds to that of $\phi$=27∼50, c=12∼49㎪. From the above testing results, the N$\_$c/ values more correspond to $\phi$ values than c values. In conclusion, this study suggests that on small dynamic cone penetration test a penetration boundary line of 5 centimeters is decided at around Li=4%, CEC=3(meq/100g) which is classified as a strong weathering soil. It also shows that as Li increases CEC increases as well, while N$\_$c/ decreases.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.4
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• pp.119-129
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• 1994

The aim of the present study is to derive an empirical formula relating the absorbed energy and the cutting length for longitudinally stiffened steel palates which are cut by a wedge, idealizing the ship bottom stiffened platings in groundings. This study is based on the test results and the investigations of some parameters affecting the cutting response, described in Part I. By dimensionless ana1ysis of the test results obtained in a quasi-static loading condition, the energy absorbed while a longitudinally stiffened plate is cut by a wedge is expressed as functions of the cutting length, the yield stress, the equivalent plate thickness and the wedge angle. Also, the dynamic effects are incorporated into the static formula such that the proposed formula can be applied to the impact loading situations. The validity of the proposed formula is checked by comparing with the results obtained by the other existing formulas or by the drop-hammer tests.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.79-82
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• 2008

It has been reported that destruction test by core collection is the most reliable of the structural concrete strength in present building construction field. But it causes low efficiency by damage and cutting in structure due to the core collection. It also has some problems in repairing. Additionally in case of strength test with management specimen, different environment compared to the structure environment cause problems about estimation precise structure strength. Therefore, it is required to develop structure direct strength test that has test values and credibility above the ones obtained by core specimen collection strength test and seasonal specimen test to suggest a reasonable and practical management method of structural concrete.

• Wind and Structures
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• v.6 no.2
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• pp.127-140
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• 2003

An investigation into the effect of corner cuts on the Strouhal number of rectangular cylinders with various dimensional ratios and various angles of attack is described. The Strouhal number given as a function of corner cut size is obtained directly from the aerodynamic behavior of the body in a uniform flow through a series of wind-induced vibration tests. For a quick verification of the validity of the Strouhal numbers obtained in this way, they are compared with the approximated the Strouhal numbers based on Shiraishi's early research. The test results show that the Strouhal number of the model with various corner cuts has a fluctuating trend as the angle of attack changes. For each cutting ratio as the angle of attack increases at each cutting ratio above $15^{\circ}$, the Strouhal number decreases gradually, and these trends are more evident for larger corner cut sizes. However, a certain corner cut size which is effective in reducing the wind-induced vibration can be identified by larger Strouhal numbers than those of other corner cut sizes. Three distinct characteristics of Strouhal number variation can be identified in three regions which are termed as Region I, II, and III based on the general trend of the test results. It is also found that the corner cut is effective in one region (Region-II) and less effective in another one (Region-III) when only the vortex-induced vibration occurs.