• Title/Summary/Keyword: Cutting rate.

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Fast Force Algorithm of End Milling Processes and Its Application to the NC Verification System (엔드밀링의 효과적인 절삭력 모델과 NC 검증시스템으로의 응용)

  • 김찬봉;양민양
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.7
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    • pp.1555-1562
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    • 1995
  • This study represents the non-dimensional cutting force model. With the non-dimensional cutting force model it is possible to estimate efficiently the maximum cutting force during one revolution of cutter. Using the non-dimensional cutting force model, the feed rate and spindle speed are adjusted so as to satisfy the maximum cutting force and maximum machining error. To verify the accuracy and efficiency of the non-dimensional cutting force model, a series of experiments were conducted, and experimental results proved and verified the non-dimensional cutting force model. The NC toolpath verification system developed in this paper uses the non-dimensional cutting force model, so that it is effective for calculating the cutting force and adjusting the cutting conditions.

A study on the Cutting Force Variation Comparison between Low CBN and Coated Low CBN Tools in Turning of SCM440 (Low CBN 코팅공구의 SCM440 선삭시 절삭력변화에 관한 연구)

  • Bang, Hong-In;Kim, Tea-Young;Oh, Sung-Hoon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.1
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    • pp.9-14
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    • 2013
  • 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.

Effects of Root Pruning, Stem Cutting and Planting Density on Survival and Growth Characteristics in Kalopanax septemlobus Seedlings (단근, 줄기 절단과 식재 밀도에 따른 음나무(Kalopanax septemlobus) 묘목의 활착 및 생장 특성)

  • Kang, Ho Sang
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.16 no.3
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    • pp.97-105
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    • 2013
  • Kalopanax septemlobus (Thunb. ex Murray) Koidz. is natively distributed in Korea. The importance of this species has been increased not only for high quality timber but for medicinal and edible uses. However, increasing market demand of K. septemlobus with illegal cutting and overexploitation has resulted in its rapid depletion and destruction of natural habitat. This study was conducted to understand the survival rate and growth characteristics of planted K. septemlobus seedlings with treatment of root pruning, stem cutting and planting density. The survival rate and growth of height and root-collar diameter for one- and two-year old seedlings with different planting densities were investigated in the clear-cut area of a Pinus densiflora stand for five years. One-year-old seedlings were treated with or without root pruning and planted with three density levels (5,000 trees $ha^{-1}$, 10,000 trees $ha^{-1}$, and 40,000 trees $ha^{-1}$). Two-year-old seedlings were treated with and without stem cutting and planted with the density of 5,000 trees $ha^{-1}$. The survival rate of one-year-old seedlings with root pruning treatment in the density of 10,000 trees $ha^{-1}$ was 92%, while that without root pruning in the density of 40,000 trees $ha^{-1}$ was 67% after five years. The height of one-year-old seedlings has been significantly affected only by planting density in the $5^{th}$ year. The survival rate of the two-year-old seedlings with stem cutting was 75.5% and greater than control (67.3%) in the $5^{th}$ year but no difference in height was shown between the two treatments from three years after plantation.

Evaluation of Cutting Characteristics Using Multiple Regression Analysis (다중회귀분석을 이용한 절삭특성 평가)

  • Lee Young Moon;Jang Seung Il;Jun Jeong Woon;Bae Hyun Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.10
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    • pp.20-25
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    • 2004
  • Using the multiple regression analysis cutting forces of turning processes have been predicted based on the cutting conditions such as feed rate(f), depth of cut(d), and cutting velocity(v). The statistical inference of the equation was checked by ANOVA test. The validity of the proposed regression analysis was verified by two sets of cutting tests of 27 cutting conditions and the additional cutting tests of 18 cutting conditions. From the results of analytical and experimental studies, it was found that there was no significant difference between the measured and predicted cutting forces. Also, the shear and friction characteristics of turning processes were analyzed with predicted cutting forces.

The Study on the Cutting Behavior of Super Duralumin(A2024-T3) (초듀랄류민(A2024-T3)의 절삭거동에 관한 연구)

  • Jun, Tae-Ok;Park, Heung-Sik;Ye, Guoo-Hyeon
    • Journal of the Korean Society for Precision Engineering
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    • v.9 no.4
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    • pp.147-153
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    • 1992
  • This study was undertaken to investigate the cutting behaviour of super duralumin (A2024-T3) with sintered carbide tool(P20). The cutting test was carried out under different conditions such as cutting speed, cutting depth and rake angle, etc. The specific cutting force Kc and Kt of vertical and radial forces decreases as cutting speed increases, especially the decrease rate of Kt becomes larger than of Kc as cutting speed increases. Kc and Kt in small cutting depth are much affected by work-hardening of surface layer. The chip width and shear angle become layer as cutting depth increases, especially chip width at feed of 0.1mm almost approaches cutting width. Relation between the friction coefficient of chip side and tool rake angle side can make the modelization studying the built-up edge size. The shear angle model equation of super duralumin generally agree with theory of Ernst-Merchant.

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Determination of Optimal Cutting Conditions Based on the Relationship between Tool Grade and Workpiece Material (피삭재와 공구재종의 상관관계에 근거한 적정 절삭조건의 결정)

  • 한동원;고성림;이건우
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.6
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    • pp.79-89
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    • 1998
  • In determining optimal cutting condition for face milling operation, tool wear is an important factor. For the purpose of establishing the relationship between various machining factors and tool wear, cutting tests have been performed. As a result, hardness and chemical composition of workpiece material, chemical composition and grain size of cutting tool and cutting speed have been selected as machining factors. In addition, relationship between feed rate and workpiece hardness has been observed. Prior to utilizing cutting conditions recommended by ‘Machining Data Handbook(MDH)’ as a knowledge base, an analysis for the validity of the MDH has been provided. Based on this analysis, tool life criteria applied by MDH has been modified. Finally, using MDH recommended data for neural network trainning, the results from the trained neural network for optimal cutting condition for some given workpiece and cutting tool can be used as reference cutting conditions.

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The Machinability Estimation Depending on Cutting Condition in A16061-T6 Turning Operations (A16061-T6의 선삭가공에서 가공조건에 따른 절삭특성 평가)

  • Choi, Tae-Kyu;Kim, Jeong-Suk;Park, Jin-Hyo;Lim, Hak-Jin
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.18 no.6
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    • pp.675-680
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    • 2009
  • Because of high specific stiffness, the aluminum alloy has been used for various industry field. Specially, the heat-treated aluminum alloy is difficult-to-machine material and machining test is necessary to evaluate and improve the machinability. In order to manufacture the functional part, appropriate cutting condition is selected by considering surface quality, machining time, and workpiece deflection by cutting force. In this investigation, the machinability of A16061-T6 is estimated by changing cutting conditions. The variable cutting conditions are cutting speed, depth of cutting, and feed rate. The estimation is done by analysis of cutting force, surface roughness, and surface shape according to the change of cutting conditions.

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A Study on the Wear of Milling Tool and Relativity of Acoustic Emission in Cutting Process (절삭중 밀링공구의 마멸과 음향방출의 관련성에 관한 연구)

  • 윤종학;김동성
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.4 no.2
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    • pp.31-37
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    • 1995
  • This study is focused on the prediction of appropriate tool life by clarifying the correlation between progressive tool wear and AE signal. when rcutting SM45C by End mill in machining center. First of all, end mill have a problem that position of sensor sticking because it is revolution tool, but I think that it can be bained specific character according to sticking Sensor in the Vise. Consequently, the following results have been obtained; 1. Each cutting speed of feed rate over 0.1mm had a tendency to increase linearly according to the RMSAE 2. The level of AE signal at the same cutting area was more sensitive to depth of cut tharn the variation of feed rate 3. In the range of cutting duringqr about 75minqr atqr cutting speed 27m/min flankqr wear turns up aboutqr 0.21mm, aboutqr 0.29mm in the caseqr of about 65minqr at 33/min, qr hereby RMSAE increased rapidly at 0.2mm flank wear, also AE-HIT and CUM-CNTS.

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Efffct of Material Removal per Tooth on the Circumferential Shape of Cylindrically Milled Parts (공구날당 소재제거량이 원통형 밀링가공물의 원주형상에 미치는 영향)

  • Kim Kwang Hee
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.5
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    • pp.62-66
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    • 2004
  • A study for investigating the effects of the cutting conditions(feed rate, radial depth of cut, cutting speed) and the tool diameter on the circumferential geometry of the cyl indrically end-mi1led workpiece is described. In this work, the circumferential geometry is characterized by the roundness error. Experimental results show that the circumferential geometry is directly affected by the material removal per tooth,which is defined as a function of the cutting speed, the feed rate and the radial depth of cut. And, the radial depth of cut is revealed to be the most critical condition among them. It is also found that the roundness error decreases when the tool diameter is larger under the same cutting conditions.

Chatacteristics of Deep Hole Machining for Duralumin Using Periodical Change of Feedrate (이송속도의 주기적 변화를 이용한 듀랄루민재의 심공가공 특성)

  • 김용제
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.240-245
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    • 2000
  • This paper presents the experimental study of drilling for duralumin A2024 with intermittently decelerated feed rate. It is achieved through a programmed periodic increase and decrease in the feed rate using a machining center. The following experimental result were performed with the objective of solving chip to disposal problems. In conventional drilling of aluminum, long continuous chips are produced that wind around the drill causing difficulties in eliminating chips from the cutting zone. In order to acquire the basic data necessary to regulate the chip profile, the relationship between cutting variables and chip shape was investigated. The following conclusions are established from the experimental results. At a suitable feed fluctuation ratio, intermittently decelerated feed drilling proved successful in breaking chips to appropriate lengths while maintaining stable cutting. Thus, it is an effective method for improving chip disposal. The amplitude of the dynamic component of cutting force in intermittent feed frilling is influenced by the feed fluctuation ratio.

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