Chip formation of rounded cutting edges

B. Bergmann,B. Denkena,T. Grove,T. Picker 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.1

In cutting processes, the performance and tool life of cutting tools are important evaluation criterions. The cutting edge microgeometry of the tools is in direct contact with the workpiece and thus influences the material flow and the loads on the cutting wedge. Research to date has demonstrated the potential of rounded cutting edges and their improved wear behavior. However, the investigations were always limited to a certain number of materials or processes. For a process-specific design of the cutting edge microgeometry, it must be possible to explicitly describe the material- and process-related contact conditions during machining with rounded cutting edges. Hence, the following article analyzes the chip formation of different cutting edge microgeometries during machining in continuous and interrupted cutting. For this purpose, planing tests on non-ferrous and ferrous materials as well as milling tests on steel alloys with differently rounded cutting tools are carried out and the effects on the chip formation process are analyzed. The results show that the minimum uncut chip thickness hmin correlates linearly to the cutting edge rounding. In addition, the correlation obtained is independent of the cutting process and the workpiece material.

양성 비혈관계 협착에서 Cutting 풍선 확장술

박정훈(Jung-Hoon Park),임진오(Jin-Oh Lim),김태형(Tae-Hyoung Kim),오제선(Jae-Seon Oh) 대한인터벤션영상기술학회 2008 대한인터벤션영상기술학회지 Vol.11 No.1

혈관 및 비혈관계에서 cutting 풍선카테타를 이용한 풍선 확장술의 유용성에 대한 많은 보고들이 되고 있다. Cutting 풍선카테타를 이용한 풍선 확장술은 이미 혈관, 간담도계, 요관 및 식도에 적용 되었고, 최근 기도와 기관지에 까지 적용되고 있다. 양성 비혈관계 협착은 주로 섬유화가 진행된 심각한 협착을 형성하는 경우가 많아 일반 풍선 확장술 후에 높은 재발율을 보이고 있다. 이러한 경우 cutting풍선카테타에 부착된 4개의 박편(薄片)을 이용하여 섬유화된 협착부위 조직에 열상을 가한후 일반 풍선 확장술을 시행할 경우 높은 치료효과를 보이고 있다. 비혈관계에서의 양성 호흡기계 협착, 양성 요도 협착에서뿐만 아니라 양성 식도 협착의 경우에서 좋은 치료효과를 보이고 있다. 이 증례보고서는 양성호흡기계 협착, 양성 요도협착 그리고 양성 식도협착에서의 cutting풍선카테타를 이용한 풍선확장술의 결과와 한계점에 대해 논하고 비혈관계에서 다양하게 사용되고 있는 cutting풍선 카테타를 이용한 풍선확장술의 유용성과 효과에 대해 보고하고자 한다. Early experiences with the use for cutting balloon have shown good initial results. Cutting balloons have been used to dilate rigid stricture in blood vessels, the ureter, the biliary system, and the esophagus. Moreover, cutting balloons recently apply to trachea and bronchus. Benign non-vascular strictures can be fibrotic and tight, which has resulted in reports of high recurrence rate after conventional balloon dilatation. Cutting balloons, features four microtomes fixed longitudinally on the surface of a balloon, were successful in creating mucosal incisions in the tight mucosa of non-vascular fibrotic stricture and then dilated by conventional balloon. Cutting balloon dilatation in benign non-vascular stricture can lead to good treatment. In this case report, cutting balloon dilatation may be a effective treatment for benign non-vascular stricture including bronchus, urethra and esophageal.

Effect of Cutting Height on Productivity and Forage Quality of Alfalfa in Alpine Area of Korea

Kim, Hak Jin,Li, Yan Fen,Jeong, Eun Chan,Ahmadi, Farhad,Kim, Jong Geun The Korean Society of Grassland and Forage Science 2021 한국초지조사료학회지 Vol.41 No.3

Cutting management has been identified as a critical factor in the alfalfa production systems because it has a significant impact on maximizing yield and maintaining the forage quality. The objective of this experiment was to determine the proper cutting height according to harvesting time for optimizing nutrient yield and forage nutritive quality of alfalfa grown in alpine regions of Korea. Alfalfa was sown at a seeding rate of 30 kg/ha in August 2018 and harvested at four cuttings in 2019 (3 May, 2 July, 11 September, and 13 October). Cutting heights were adjusted at 5, 15, and 25 cm above the soil surface. Alfalfa plant was tallest at the third cutting (109 cm), which was on average 35 cm taller than the first or second cutting. Relative feed value (RFV) remained unaffected by cutting height at the first harvest, but increased consistently in subsequent harvests as cutting height increased. Alfalfa collected at the first and fourth cuttings had the highest RFV (mean 152), which was on average 8 and 67 units higher than the second and third harvests, respectively. At each harvest, in vitro dry matter digestibility was highest in alfalfa cut at a 25-cm height. Dry matter (DM) production at each cutting height was highest in the first cutting, accounting for on average 36-37% of total annual DM production, and lowest in the fourth harvest, accounting for about 11-13% of the total DM yield. The total dry matter production (in four harvests) was 4,218 kg/ha higher when alfalfa was subjected to a cutting height of 5 cm rather than 25 cm. Cutting height had no effect on total crude protein yield, but from the first to fourth cutting, the protein yield followed a decreasing trend. Finally, there were visible declines in forage nutritive quality when alfalfa was cut at a shorter height. However, the magnitude of difference in total forage yield may outweigh the slight decline in forage quality when alfalfa is cut at a lower height. The findings of this study could help the alfalfa growers make better harvest management decisions.

상수리나무 임분 내에서 벌채 유형에 따른 조림목의 생장 특성

신유승 ( Yu Seung Shin ),송선화 ( Sun Hwa Song ),양아람 ( A Ram Yang ),황재홍 ( Jaehong Hwang ),박용목 ( Yong Mok Park ) 한국환경과학회 2014 한국환경과학회지 Vol.23 No.6

The objective of this study was to evaluate the effect of cutting types on microclimate and growth characteristics of afforested tree in Quercus acutissima stand after different types of cutting. The difference in temperature reaching 5.2℃ was shown in between clear cutting and selective cutting treatments. On July and August days with temperatures more than 35℃ often appeared in clear cutting stand. The values of VPD in July and August were higher than those in other months. Maximum VPD of 3.99 kPa was shown in clear cutting stand on May 23 as a prolonged rainless days appeared. However, VPD in selective cutting stand always stayed under 3.0 kPa throughout growing season. A higher intensity was shown in clear cutting and strip clear cutting stands, reaching to more than 1,600 μmol m-2 s-1 at midday on early August, while that in selective cutting stand stayed about 1,500. In relative growth rate selective cutting stand showed a significantly higher relative growth rate in plant height than those in other cutting stands (p<0.05). The number of leaf in current-year branches significantly increased in selective cutting stand, whereas no increase was shown in clear cutting and strip clear cutting stands (p<0.05). In addition, relative elongation rate of current year branch also showed higher values in selective cutting stand compared with that in strip clear cutting stand (p<0.05). However, leaf mass per unit area (LMA) was higher in order of strip clear cutting, clear cutting, and selective cutting stands. From these results it is concluded that environmental conditions in clear cutting and strip clear cutting stands during growing season are more stressful to afforested tree species, resulting in lower relative growth in plant height, elongation of current-year branches, and leaf number per branch compared with those in selective cutting stand. Consequently, more data must be accumulated in the field to find out best cutting type in plantation considering the adaptational characteristic of each tree species varies with species and life span of tree is long.

소형부품 및 시험용 시편 절단을 위한 소형 컷팅기 개발

신오철(O-Chol Shin),정원지(Won-ji Chung),박수성,김재민(Jae-min Kim),Su-min Kim 한국생산제조학회 2009 한국공작기계학회 추계학술대회논문집 Vol.2009 No.-

A small part and metal parts, test piece used for industries are cutted by lathe and a large cutting machine, a hand grinder. Cutting-off cause noise and need a secondary processing because broken a section, especially in case of a large cutting machine and a hand-grinder often used as cutting a small part. So this study had developed a small cutting machine(4' cutting wheel). It apply large cutting machine(10'~12' cutting wheel) and hand-grinder (4' cutting wheel). An efficiency test using a small cutting machine find out attrition rate of cutting wheel higher than hand-grinder. but a section's pattern of workpiece that caused by cutting wheel is uniform. Also burr from the boundary is lower than hand-grinder. Accordingly developed a small cutting machine is expected to help cutting a small part and a test pieces.

국화 '백마'의 플러그 육묘시 삽목조건이 삽목묘와 절화 생육에 미치는 영향

유용권(Yong Kweon Yoo),노용승(Yong Seung Roh) 한국원예학회 2012 원예과학기술지 Vol.30 No.1

This study was carried out to examine the effect of cutting condition on the growth of rooted cuttings and their subsequent growth of cut flower in plug cutting of Dendranthema grandiflorum 'Baekma'. The more leaves were attached to the cutting, the higher shoot growth of rooted cutting was observed. Cutting with two to six leaves was effective in shoot growth and rooting than any other treatment. Shoot growth of rooted cutting was not affected by cutting length, but rooting was better in 5 to 7 cm long cutting. Shoot growth and rooting of rooted cutting was promoted by increasing the cutting diameter, and rooting was better in 3.6-4.2 ㎜ thick cutting than 3.1 ㎜ thick cutting. As the treating concentration of NAA increased, shoot growth was inhibited and root length shortened in rooted cutting. Soaking with 100 ㎎·L-¹ α-naphtalene acetic acid (NAA) for 1 h was effective in shoot growth and rooting. Root growth such as root number, root length, and root weight was better in rooting medium mixed with 2:2 of peatmoss:perlite than the other treatments. When rooted cutting produced from cutting with four or six leaves was planted, better length, weight, and leaf number of cut flower was observed. In rooted cutting produced with 7-9 ㎝ long cutting, growth of cut flower such as length, weight, and ray flower number was more effective than the others. Therefore, it is recommended that the 7 ㎝ long and 3.6 ㎜ thick cutting with four to six leaves is used to improve their rooting and subsequent growth of cut flower in plug cutting of Dendranthema grandiflorum 'Baekma'.

Cutting performance of thick steel plates up to 150 mm in thickness and large size pipes with a 10-kW fiber laser for dismantling of nuclear facilities

Shin, Jae Sung,Oh, Seong Yong,Park, Hyunmin,Chung, Chin-Man,Seon, Sangwoo,Kim, Taek-Soo,Lee, Lim,Lee, Jonghwan Elsevier 2018 Annals of nuclear energy Vol.122 No.-

<P><B>Abstract</B></P> <P>The cutting performance of thick steel plates and large size pipes with a 10 kW fiber laser was studied for the dismantling of nuclear facilities. First, thick steel plates of up to 100 mm were tried to be cut at a high speed. For the thickness of 100 mm, both stainless steel and carbon steel plates were cut at maximum cutting speeds of ∼30 mm/min. And narrow kerf widths of less than 5 mm were obtained for all cutting tests. Second, a 150-mm thick stainless steel plate near the cutting thickness limit was attempted to be cut. The specimen was able to be cut even with a low cutting speed of 3 mm/min. To the best of our knowledge, this thickness is the largest among the published reports with a laser power of 10 kW. And this corresponds to a cutting capability in which most thick structures in a nuclear reactor can be cut. In addition, large size stainless steel pipes were also attempted to be cut. For a 165 mm diameter pipe, it was possible to be cut at high speed by one scan at a speed of 50 mm/min and round trip scan at a speed of 100 mm/min. This result implies that high-speed cutting was also possible for most pipe-type components inside the nuclear reactor. As a result, our 10-kW laser cutting system showed very efficient cutting performance in terms of the cutting speed and thickness. Moreover, the cuttings showed narrow kerf widths of less than 5 mm even for very thick steel of up to 150 mm in thickness. In the future, it is expected that the results of this work will contribute to cutting thick metal structures as basic research data in the dismantling of nuclear facilities using a laser. In addition, it is also expected that this work will contribute to other industrial fields requiring a thick steel cutting technique.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cutting of thick steel plates and large pipes with a 10 kW fiber laser was studied. </LI> <LI> Stainless steel and carbon steel plates of up to 100 mm were cut at a high speed. </LI> <LI> A 150-mm thick stainless steel plate was also able to be cut. </LI> <LI> A 165 mm diameter pipe was possible to be cut. </LI> <LI> Our system showed efficient cutting performance in terms of speed and thickness. </LI> </UL> </P>

A Short Review on the Mechanical and Thermal Processes for Underwater Cutting of Metal Structures

Do Yeong Mun(문도영),Young Tae Cho(조영태) 한국기계가공학회 2020 한국기계가공학회지 Vol.19 No.1

Underwater cutting has a different mechanism than dry cutting, and there are more restrictions than benefits. Due to these constraints, research and development of underwater cutting has been very limited. At present, reactor dismantling is emerging as an important task worldwide, and reactor pressure containers, a key part of the reactor, are decommissioned based on underwater cutting. Reactor pressure containers are high-level radioactive waste, which is one of the main goals of today, such as to bridge the gap between environmental, safety, and cutting performance; hence, a process suitable for cutting should be applied. Therefore, many studies are being conducted on underwater cutting in connection with the dismantling of nuclear reactors in various areas in order to find appropriate processes. This paper first introduces the core technology of underwater cutting processes and discusses various processes. The emphasis is then placed on the adequacy of the reactor dismantling application. More specifically, we examine the suitability for the mechanical and thermal cutting processes, respectively, to find a solution suitable for dismantling a reactor. We discuss how each solution can sufficiently perform the specified functions at each stage of reactor dismantling and suggest that these processes can perform all of the work of underwater cutting.

An experimental study on the development and verification of NCC(new concrete cutting) system

박종협,한종욱 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.2

This paper introduces the development process of NCC(New Concrete Cutting) system and analyzes first verification test. Based on the first verification test results, some problems of NCC system have been newly modified. We carry out the second verification test. We tried to verify cutting performance and dust control efficiency of NCC system through the cutting test of concrete bridge piers. In particular, this verification test strives to solve the problem of concrete dust, which is the biggest problem of dry cutting method. The remaining dust problems in cutting section tried to solve through this verification test. This verification test of the NCC system shows that the dust problem of dry cutting method is closely controlled and solved. In conclusion, the proposed NCC method is superior to the dry cutting method in all aspects, including cutting performance, dust vacuum efficiency and cooling effect. The proposed NCC system is believed to be able to provide eco-friendly cutting technology to various industries, such as the removal of the SOC structures and the dismantling of nuclear plants, which have recently become a hot issue in the field of concrete cutting.

Characteristics of Cutting Surface According to Cutting Direction and Laser Output During Laser-Oxygen Hybrid Cutting for Nuclear Power Plant Dismantling Application

DoYeong Mun,SunIl Kim,MinGyu Choi,DongHyun Kim,IlWoo Moon 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.2

Thermal cutting processes that can be applied to dismantling nuclear power plants include oxygen cutting, plasma cutting, and laser cutting. According to the global trend, research projects are being carried out in various countries to upgrade laser cutting, and many studies are also being conducted in Korea with plans to apply laser cutting processes when dismantling nuclear power plants. However, with the current technology level of the laser cutting process, the maximum thickness that can be cut is limited to 250 mm. Therefore, in this study, a laser-oxygen hybrid cutting process was implemented by adding a laser heat source to the oxygen cutting process that can cut carbon steel with a thickness of 250 mm or more (RV, beam, column, beam, etc.) when dismantling the nuclear power plant. This has the advantage of improving the cutting speed and reducing the cutting width Kerf compared to conventional oxygen cutting. In this research, the laser-oxygen hybrid cutting process consisted of laser cutting to which Raycus’ 8 kW Fiber Laser power source was applied and oxygen cutting to which hydrogen was applied with Fuel Gas. The oxygen torch was placed perpendicular to the test piece, and the laser head was irradiated by tilting 35° to 70°. The effects of cutting directions on quality and performance were studied, and cutting paths were selected by comparing cutting results. Thereafter, it was confirmed that there is an optimal laser output power according to the cutting thickness by studying the effect on the cutting surface quality by changing only the laser output power under the same cutting conditions. The results of this study are expected to be helpful in the remote cutting process using laser-oxygen hybrid cutting when dismantling domestic nuclear power plants in the future.