비절삭 저항상수에 따른 절삭력 예측

김종도,윤문철 한국기계가공학회 2019 한국기계가공학회지 Vol.18 No.10

Few studies have been conducted regarding theoretical turning force modelling while considering cutting constant. In this paper, a new cutting force modelling technique was suggested which considers the specific cutting force coefficients for turning. The specific cutting force is the multiplication of the cutting force coefficient and uncut chip thickness. This parameter was used for experimental modelling and prediction of theoretical cutting force. These coefficients, which can be obtained by fitting measured average forces in several conditions, were used for the formulation of three theoretical cutting forces for turning. The cutting force mechanism was verified in this research and its results were compared with each of the experimental and theoretical forces. The deviation of force was incurred by a small amount in this model and the predicted force considering feed rate, nose radius, and radial depth shows a physical behavior in main force, normal force, and feeding force, respectively. Therefore, this modelling technique can be used to effectively predict three turning forces with different tool geometries considering cutting force coefficients.

정면밀링에서 절삭력을 이용한 절입비와 절삭력비의 실시간 추정

김명곤,권원태 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.4

In this paper, presented is a method of on-line estimation of the radial immersion ratio and cutting force ratio using cut-ting force. When a tooth finishes sweeping, sudden drop of cutting forces occurs. These force drops are equal to the cutting forces that act on a single tooth at the swept angle of cut and can be obtained from cutting force signals in feed and cross-feed directions. The ratio of cutting forces in feed and cross-feed directions acting on the single tooth at the swept angle of cut is a function of the swept angle of cut and the ratio of radial to tangential cutting force. In the research, it is found that the ratio of radial to tangential cutting force is not affected by cutting conditions and axial rake angle. Therefore, the ratio of radial to tangential cutting force determined by just one preliminary experiment can be used regardless of the cutting conditions. Using the measured cutting forces, the radial immersion ratio is estimated along with the cutting force ratio at that immersion angle. Various experiments show that the radial immersion ratio and instantaneous ratio of the radial to tan-gential direction cutting force can be estimated by the proposed method very well.

정면밀링가공에서 쟁기력을 고려한 3차원 절삭력 모델링

이성세,김명곤,권원태 서울시립대학교 산업기술연구소 1998 산업기술연구소논문집 Vol.6 No.2

Cutting force is obtained as a sum of chip removing force and ploughing force. Chip removing force is estimated by multiplying specific cutting pressure by cutting area. Since ploughing force is caused from dullness of a tool, its magnitude is constant. By using the linearity of chip removing force to cutting area and th constancy of ploughing force regardless of depth of cut if it is over a certain limit, each force is separated from measured cutting force and used to establish cutting force model. New rotation matrix to convert the measured cutting force in reference axes into the forces in cutter axes is obtained by considering that tool angles are projected angles from cutter axes to reference axes. Spindle tiIt is also considered for the model. The predicted cutting force estimated from the model is in good agreement with the measured force.

정면밀링가공에서 쟁기력을 고려한 3차원 절사력 모델링

권원태,김기대 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.2

Cutting force is obtained as a sum of chip removing force and ploughing force. Chip removing force is estimated by multiplying specific cutting pressure by cutting area. Since ploughing force is caused from dullness of a tool, its magnitude is constant if depth of cut is bigger than a certain value. Using the linearity of chip removing force to cutting area and the constancy of ploughing force regardless of depth of cut which is over a certain limit, each force is separated from measured cutting force and used to establish cutting force model. New rotation matrix to convert the measured cutting force in reference axes into the forces in cutter axes is obtained by considering that tool angles are projected angles from cutter axes to reference axes. Spindle tilt is also considered for the model. The predicted cutting force estimated from the model is in good agreement with the measured force.

Efficient Analysis of CFRP Cutting Force and Chip Formation Based on Cutting Force Models Under Various Cutting Conditions

Dong-Gyu Kim,Seung-Han Yang 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.7

The cutting characteristics of unidirectional carbon fiber-reinforced plastic (CFRP) during zig-zag milling, which is the most used milling tool path in the industry, were analyzed. Cutting force and chip formation are the most useful indicators of cutting performance. Here, cutting force and chip formation were analyzed in up- and down-milling, then compared with those parameters in zig-zag milling. CFRP cutting force models for up- and down-milling were used for analysis of cutting force. Chip formations were predicted via simulations of fiber cutting angle. This simulation-based study overcame various experimental limitations regarding CFRP cutting force. The specific cutting forces of various fiber cutting angles were derived from cutting experiments involving unidirectional CFRP. The specific cutting forces decreased with increasing chip thickness. These results are similar to the size effect observed in metal machining. Cutting force analysis was performed with a focus on change in feed direction and rate of radial immersion. In zig-zag milling, the optimal feed direction rapidly changed at a radial immersion of 30%. At a radial immersion of 75%, the difference in cutting force related to the change in the feed direction was large. Type I (delamination-type) chip formation was dominant in the optimal feed direction because specific cutting force was lower in the Type I section than in regions of other chip formation types/

Micro Cutting of Tungsten Carbides with SEM Direct Observation Method

jung, Heo-Sung The Korean Society of Mechanical Engineers 2004 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.18 No.5

This paper describes the micro cutting of wear resistant tungsten carbides using PCD (Poly-Crystalline Diamond) cutting tools in performance with SEM (Scanning Electron Microscope) direct observation method. Turning experiments were also carried out on this alloy (V50) using a PCD cutting tool. One of the purposes of this study is to describe clearly the cutting mechanism of tungsten carbides and the behavior of WC particles in the deformation zone in orthogonal micro cutting. Other purposes are to achieve a systematic understanding of machining characteristics and the effects of machining parameters on cutting force, machined surface and tool wear rates by the outer turning of this alloy carried out using the PCD cutting tool during these various cutting conditions. A summary of the results are as follows: (1) From the SEM direct observation in cutting the tungsten carbide, WC particles are broken and come into contact with the tool edge directly. This causes tool wear in which portions scrape the tool in a strong manner. (2) There are two chip formation types. One is where the shear angle is comparatively small and the crack of the shear plane becomes wide. The other is a type where the shear angle is above 45 degrees and the crack of the shear plane does not widen. These differences are caused by the stress condition which gives rise to the friction at the shear plane. (3) The thrust cutting forces tend to increase more rapidly than the principal forces, as the depth of cut and the cutting speed are increased preferably in the orthogonal micro cutting. (4) The tool wear on the flank face was larger than that on the rake face in the orthogonal micro cutting. (5) Three components of cutting force in the conventional turning experiments were different in balance from ordinary cutting such as the cutting of steel or cast iron. Those expressed a large value of thrust force, principal force, and feed force. (6) From the viewpoint of high efficient cutting found within this research, a proper cutting speed was 15 m/min and a proper feed rate was 0.1 mm/rev. In this case, it was found that the tool life of a PCD tool was limited to a distance of approximately 230 m. (7) When the depth of cut was 0.1 mm, there was no influence of the feed rate on the feed force. The feed force tended to decrease, as the cutting distance was long, because the tool was worn and the tool edge retreated. (8) The main tool wear of a PCD tool in this research was due to the flank wear within the maximum value of $V_{max}$ being about 260 $\mu\textrm{m}$.

Low CBN 코팅공구의 SCM440 선삭시 절삭력변화에 관한 연구

방홍인(Hong-In Bang),김태영(Tea-Young Kim),오성훈(Sung-Hoon Oh) 한국기계가공학회 2013 한국기계가공학회지 Vol.12 No.1

In recent years, high hardness steel is used for most of the material in many areas including aircraft, nuclear power, space exploration and automotive parts. Low CBN tools are widely used in industrial field which can effectively process high hardness steel of HRC 45 or harder. The results of this study demonstrated, when high hardness steel, SCM440 is turned with Low CBN tools coated with TiN and TiAlN coatings respectively, that both the thrust force and cutting force tends to increase with more increase in cutting force than thrust force, as the feed rate increases at constant cutting speed. In addition, the size of the cutting force and thrust force does not change with the increased cutting speed at the same feed rate, but the tool life is reduced if the cutting speed is increased to shorten the machining time. Therefore, it is recommended to limit the cutting speed at 250 m/min maximum or less. Furthermore, comparing the cutting force of the three tools at the same cutting condition, Tin coating tool showed the smallest cutting force and Low CBN was the next, and the TiAlN coating tools showed the largest cutting force.

비절삭저항 상수 변화에 따른 절삭력 분석

김종도(Jong-Do Kim),윤문철(Moon-Chul Yoon) 한국기계가공학회 2014 한국기계가공학회지 Vol.13 No.2

Considering the run-out effect and cutting force coefficients, the cutting force profile of half immersion end-milling was analyzed in detail. The effects of three specific cutting-force coefficients and three edge-force coefficients are verified. Through a detailed investigation, it is proved that the radial cutting force coefficients and are the major factors which increase the cutting forces Fx and Fy in end-milling. However, the axial cutting force coefficients have no influence on the force Fx and Fy changes in end-milling. Also, the analyzed end-milling force model shows good consistency with the actual measured force with regard to Fx and Fy. Thus, this model can be used for the prediction of the force history in end-milling with run-out,and it incurs a different force history with different start and exit immersion angles as well as holding effects.

TiAIN을 코팅한 WC공구의 절삭성능에 관한 연구

김현자,최현철,김영대,김일선,노태영,이규용 釜慶大學校 2001 釜慶大學校 論文集 Vol.6 No.-

Thin film of TiAlN was deposited onto ISO P20 tungsten carbide cutting insert tip substrate specimen using the FVAS (filtered vacuum arc system) at the substrate temperature of 80℃. Cutting and wear tests have been performed to the TiAlN coated and uncoated WC specimen, respectively under the same cutting conditions for the comparison. Cutting forces and tool wear of coated and uncoated carbide cutting tools were investigated by means of cutting length and cutting forces. Also tool wear and tool life were analyzed using the 3ch tool dynamometer amp lifier and oscilloscope. In this study cutting tests for the cutting performance of TiAlN coated WC-Co P20 to the steel alloy of SNCN420 have been curried out. Through the comparisons of cutting forces during the cutting tests and tool wear, we got the conclusions as follows.; ① In usual cutting conditions, main cutting force component showed higher value than the thrust force normal to the cutting direction especially cutting forces in the of early stage on cutting tests. But, after loosing the protective hard thin film on substrate or insert tip, the thrust force normal to the cutting direction showed much higher than main cutting force component. ② Within the range of 0.3㎜ build up edge in P20 insert tip, TiAlN coated tip was evaluated more stable in flank wear and less in crater wear than the uncoated specimen. ③ Through the wear growth curve of the specimen, tool life differences of uncoated and TiAlN coated tip at high speed (V=250[m/min]) was higher than the low speed(V=200[m/min]) case, compared to the average but the tool wear was almost same in both specimen for the case of normal wear occurred.

밀링가공에서의 주축 변위 측정을 통한 절삭력 예측

장훈근,장동영,한동철 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

Cutting force is important to understand cutting process in milling. To measure cutting force, tool dynamometer is widely used but it is hard to apply in workshop condition. Cutting force measurement which doesn't affect cutting process is needed. Using relations between cutting force and spindle displacement, cutting force can be predicted. Cylindrical capacitive sensor was used to measure spindle displacement during cutting. And signals from tool dynamometer collected to compare with spindle displacement. The result shows spindle displacement has a linear relation with cutting force. Using this result, a simple method to predict cutting force could be applied at workshop condition.