• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_3
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• pp.1197-1204
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• 2023

Ti-alloy, a high-strength alloy material among the materials used in aircraft that are trending toward lighter weight, is classified as a difficult-to-cut material that requires a lot of energy for cutting. Cutting in a high-temperature environment is considered one means of making this possible, and various studies have been conducted on it. In particular, research on LAM (Laser Assisted Machining (LAM)), which utilizes laser heating of the cutting area, is being actively conducted. Before processing of the milling cutter begins, the temperature is raised locally by the laser irradiated through the laser head carrier, and the resistance during milling is reduced. Therefore, in this paper, in order to derive such conditions, we performed heat transfer analysis according to transfer conditions and compared it with actually applied test data to use it to establish appropriate processing conditions.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.1-8
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• 2020

While dental clinics still use the ultrasonic scaling/surgery tool for teeth scaling and cleaning the tool's use is expanding steadily to include treatment of damaged teeth and bone tissue. In this study, a handpiece moving system (HMS) was developed to evaluate bone scaling and cutting in the field of dentistry. The HMS, through a scaling test of bone using a scaler tip, it was able to identify surface damage. Additionally, a thermos-graphic camera was used to observe the temperature distribution that occurred during the bone scaling and cutting process. Consequently, we found that increasing the working load increased the amount of surface damage. Changes in temperature distribution occurred slowly and were maintained within safety bounds for 10 minutes. Going forward, we will compare the HMS performance on scaling and cutting with other devices.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.135-140
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• 2001

In metal cutting at the tool-chip interface, friction generates considerable amount of heat. Thus, tile .knowledge of wear properties or the cutting tool material in high temperature has been known as one of tile important factors in need of clarification. The authors presented the wear properties of 5%V-5%Co-1%Nb high speed steel, fabricated by powder metallurgy, in room temperature in a previous article. The objective of this paper is to clarify tile effects of temperature ell its wear properties. Wear tests in sliding conditions under various temperatures have been conducted. The results indicate that tile wear properties of tile tool material in high temperature as well as in room temperature are excellent. It may be deduced that the oxide layer formed on the vol-n surface at high temperature is stable enough to prevent wear due to tile high temperature strength of its matrix.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.56-62
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• 2013

The laser cutting process which is flexible and rapid usually provides a better result in cutting of flexible printed circuit boards (FPCB). However, circuit-short by the re-deposition of debris from laser ablation or its heat affect zone (HAZ) on the cutting surfaces can be a problem. A laser cutting process of FPCB in the presence of liquid can minimize these negative effects. The temperature distribution of copper and polymer parts of FPCB was analyzed with numerical simulation and the experimental results were presented to evaluate this process. Generally, laser cutting under liquid has advantages of less re-deposition of carbides and less HAZ on the cutting edges. However, bubble generation and laser beam control through the liquid media should be considered carefully to obtain a successful result.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.4
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• pp.20-26
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• 2010

Any relative deformation between the cutting tool and the workpiece at the machining point, results directly in form and dimensional errors. The source of relative deformations between the cutting tool and the workpiece at the contact point may be due to thermal, weight, and cutting forces. This paper presents an investigation into dry and fluid machining with the objective of evaluating shape accuracy effect for the turning process of Al6061. The thermal distribution of cutting tool and cutting force was predicted using finite element method after measuring the temperature of the tool holder. To reach this goal, shape accuracy turning experiments are carried out according to cutting conditions with dry and fluid machining methods. The variable cutting conditions are cutting speed, depth of cutting and feed rate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.1017-1020
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• 2002

The pure Ti is taken annealing process for one hour at 90$0^{\circ}C$. The pure Ti is sufficient for ASTM B348 Grade2. The rolling mill roll the Ti-8Ta-3Nb(wt%) which became vacuum melting in arc furnace until the length is about 45mm and the thickness is about 6.05mm. Then it is made 6mm$\times$6mm$\times$44mm by wire cutting with EDM and it is made ∮ 6mm by rough cutting with the general purpose lathe. The machining accuracy of implant parts in the dental and medical science are decided by dimension, shpe, straightness, surface roughness. It is difficult to cut for the Ti alloy. It is caused problems of straight degree and surface roughness to the Ti alloy have many cases which length is smaller than diameter in cutting. Total 24 specimens different kind of 4 alloies are used in experiment to gain a cutting property. According to the cutting velocity, cutting depth, cutting temperature, feed and clearance angle experiments are performed. Conclusively it is expected that cutting depth of 0.5mm, feed velocity of 0.07mm/rev and cutting velocity of 80m/min could make a suitable result.

• Journal of Korean Society of Forest Science
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• v.98 no.4
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• pp.491-495
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• 2009

This study was conducted to investigate the propagation characteristics of Cephalotaxus koreana by cutting, whose plant has been known to new anticancer treatments. The treatments of plant growth regulators, cutting media temperature and growing media were investigated to know the rooting ability of cuttings. For rooting formation affected by plant growth regulators and its concentration, The application of IBA 100 mg/L was most effective in all of the characteristics including rooting rate of 88.5%. The optimum media temperature by cutting was $24^{\circ}C$ (treatment IBA 100 mg/L, rooting rate 84.6%), predicting that greenwood cutting from June to July is most effective. VPPL (vermiculite+peatmoss+perlite 1:1:1(v/v/v)) showed the highest value in all of the characteristics including rooting rate of 68.5% for the effect of growing media on rooting formation.

• Horticultural Science & Technology
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• v.16 no.3
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• pp.355-357
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• 1998

Various temperatures and plant growth regulators were assessed to investigate the nature of the dormancy and bud sprouting of stem cutting of Hibiscus syriacus 'Honghwarang'. The bud sprouting was promoted as temperature increased. Under $30^{\circ}C$ condition, stem cuttings began sprouting at 4days after cutting and showed 100% sprouting at 6 days after cutting. With GA or BA treatment, the cuttings started sprouting at 6 days after cuttings under $25^{\circ}C$ condition and reached 65% sprouting, which was not different from the results without hormone treatments. However, ABA dipping under below $25^{\circ}C$ condition resulted in low sprouting, whereas under over $25^{\circ}C$ condition they started sprouting at 6 days after cutting and reached 93% at 12 days after cutting, which indicated that ABA is not effective on inhibition of sprouting under high temperature condition.

• Korean Journal of Veterinary Research
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• v.56 no.2
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• pp.85-89
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• 2016

We tested a set of conditions for obtaining optimal tissue quality in preparation for histology in samples of mouse brain. C57BL/6J mice were sacrificed and perfused with 4% paraformaldehyde, after which the brains were removed and dehydrated in 30% sucrose solution. The brains were then divided into four groups according to freezing temperature and usage of optimal cutting temperature (OCT) compound. Next, we stained the sectioned brain tissues with Harris hematoxylin and eosin Y and immunohistochemistry was performed for doublecortin. The best quality tissue was obtained at $-25^{\circ}C$ and by not embedding with the OCT compound. When frozen at $-25^{\circ}C$, the embedded tissue was significantly damaged by crystals, while at $-80^{\circ}C$ there were no meaningful differences between qualities of embedded- and non-embedded tissues. Overall, we identified a set of conditions to obtain quality frozen brain sections. Our developed protocol will help resolve matters associated with damage caused to sectioned brain tissue by crystal formation during freezing.

• Fire Science and Engineering
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• v.26 no.3
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• pp.60-66
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• 2012

In this study, it was evaluated the fire risk during welding cutting tasks. Welding-cutting machines are representatively used at construction sites. Inverter AC/DC TIG welding macnine and inverter air plasma cutting machine were used in experiments. Temperature of spreaded cinders was measured using a thermal camera. Cinder sizes and spread range were measured according to the height and input current. It was also evaluated the fire risk during welding-cutting process, when flammable materials were located around the working area. There were used hay, dust fence, urethane foam, vinyl, paper and oil as flammable materials. Temperature of spreaded cinders was reached at about $450^{\circ}C$. Cinders were spread approximately 4.7 m, when a worker carried out cutting process at 2.5 m height. The possibility of a fire is very high, when flammable materials were located around the working area.