• Title/Summary/Keyword: 절삭속도

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A Study on Ultrasonic Vibration Cutting of Carbon Fiber Reinforced Plastics (탄소섬유강화 플라스틱의 초음파 진동절삭에 관한 연구)

  • 김정두;이은상;최인휴
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.1
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    • pp.24-33
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    • 1994
  • The main applications of CFRP are sports, aerospace and general industrial uses including automobiles. As this application fields expands the opportunity of machining, but CFRP is difficult to cut because of delamination of the composites and the short tool life. In this paper, the machinability of multidirectional CFRP by means of ultrasonic vibration cutting, which has been verified experimentally investigated.The experimentally to be highly effective in view of cutting force and surface quality.

Detection of Built-up Edge by AE Signal Analysis (AE 신호 분석에 의한 구성인선의 감지)

  • Oh, Min-Seok;Won, Jong-Sik;Jung, Youn-Gyo
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.3
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    • pp.18-24
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    • 1999
  • ThisPaper investigates the feasibility of using acoustic emission signal analysis for the detection of built-up edge during machining. Experiments were conducted on a CNC-lathe using conventional carbide insert tools under various cutting conditions. The cutting forces were also measured for comparisons. Experimental evidence is presented which indicates that the presence of a built-up edge can significantly affect the generation of acoustic emission in metal cutting. It is shown that under conditions in which a built-up edge is generated, the variation of $AE_{rms}$ signal with cutting speed can be quite different from the generally accepted linear, monotonic increase as previously reported. The feasibility of utilizing $AE_{rms}$ in built-up edge sensing is suggested.

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A Study on the Coated Characteristics of Ceramic Tools (코팅공구의 절삭성능에 관한 연구)

  • 유봉환
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.1
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    • pp.96-101
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    • 2000
  • Ceramic, PCD and CBN tools are available for the difficult-to-cut-materials such as hardened carbon tool steel, stainless steel, Inconel 718 and etc.. Ceramic toolsare likely to be chipped and abruptly broken before the appearance of normal wear in turning. Ther2efore ceramic tools are suitable for continuous cut in turning not for intermittent in milling. In this study, TiN/TiCN multi-layer coated ceramic tools were found to restrain the chipping, breaking and early fracture and to increase the critical cutting speed owing to TiN/TiCN multi-layer coating in Arc Ion Plating of PVD method.

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A Study on the Early Fracture Characteristics of Ceramic Tool for Carbon Tool Steel (탄소공구량에 대한 세라믹공구의 초기파손 특성에 관한 연구)

  • Kim, K.L.;B.H. Ryu
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.6
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    • pp.112-119
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    • 1995
  • Early fracture and cutting force of ceramic tool for hardened STC3 steel was investigated in this study. It was found that early fracture of ceramic tool was mostly occurred before normal wear was progressed beyond a critical cutting speed and normal wear was performed under the critical cutting speed. The relationships among critical cutting speed, which was a cause of early fracture, suggested cutting cross section, that is, maximum thickness of cut and width of cut, and cutting force were examined. The following conclusions were obtained: (1)Critical cutting speed showed a high value in the case of small maximum thickness of cut and large nose radius, but was not influenced by width of cut, (2)Principal, feed and radial force, respectively, showed the proportional value to constant cutting area, width of cut and maximum thickness of cut orderly, (3)Occurrence of early fracture was dependent upon radial force.

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Robust Optimization of the Solenoid Assembly in Electromagnetic Limited Slip Differential by Considering the Uncertainties in Machining Variables (가공변수의 불확실성을 고려한 전자제어식 차동제한장치 솔레노이드 어셈블리의 강건 최적설계)

  • Oh, Sang-Kyun;Lee, Kwang-Ki;Suh, Chang-Hee;Jung, Yun-Chul;Kim, Young-Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.10
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    • pp.1307-1313
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    • 2011
  • The mechanical limited slip differential (LSD) in vehicles is being replaced by the electromagnetic LSD because of its fast response and better active control characteristics. The coil housing made of STS 304 is one of the most important parts in the solenoid assembly of the electromagnetic LSD. High geometrical accuracy is a prerequisite for the manufacture of such coil housings, but precision machining is difficult because of the use of STS 304 thin plate and the variance in machining variables. The aim of this study is to optimize the mean and variance of the shape accuracy in the coil housing by finding a robust solution for the machining process conditions. The mean and standard deviation of the jaw contact pressure, cutting speed, and feed rate are considered to be the major parameters for minimizing the geometrical mean and variance. The response surface model based on the second-order Taylor series is combined together to minimize the mean and variance of the shape accuracy of the coil housing.

Study on Cutting Processing Characteristic of Ti alloy (Ti 합금의 절삭 가공특성에 관한 연구)

  • 반재삼;이경원;김규하;조규종
    • Proceedings of the Korean Society of Precision Engineering Conference
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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.

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A Study on Surface Roughness of Aluminum 7075 to Nose Radius and Cooling Method in CNC Lathe Machining (CNC선반가공에서 노오즈 반경과 냉각방법에 따른 알루미늄7075의 표면 거칠기에 관한 연구)

  • Noh, Young-Ho
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.4
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    • pp.85-91
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    • 2015
  • Current world aircraft industry studies on the precision of the product are in active progress. Particularly in terms of improving the quality of processed products in terms of the surface roughness of the dimensional accuracy, fatigue strength, and corrosion resistance, which affect a lot of research on surface roughness, has been investigated. In this study of aluminum alloy, 7075 aircraft aluminum is used in a cutting CNC lathe machine for the cutting speed and feed rate according to the cutting experiments that were conducted. Additionally, the machine tool of the cooling method soluble cutting oil, insoluble cutting oil by cooling, and cooling the workpiece by cutting surface roughness will be investigated. Through the method and soluble cutting oil coolant cooled by the cutting speed increases, the value of surface roughness showed a regular result. Tool nose radius of 0.8 mm than 0.4 mm picture of when approximately 50 of the surface roughness values were less.

Improvement of Surface Roughness by the Cutting Speed Control for Turning Operation (선삭에서 절삭 속도 제어를 통한 표면 거칠기 향상)

  • Choi, Jong-Hwan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.7 no.2
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    • pp.23-30
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    • 2008
  • As a basic machining process, turning is a widely used machining process in which a single-point cutting tool removes material from the surface of a rotating material. A common method of evaluating machining performance is to measure the surface roughness. In a turning operation, it is important to select cutting conditions for achieving high cutting performance. As a rule, cutting conditions can be classified into feed rate, depth of cut and insert radius. While cutting process even though cutting conditions are optimized, the average roughness can be deterioration due to wear of the cutting tool edge. In this study, the aim is to maintain the average roughness even though the cutting condition is irregularly changing within the predictable range due to the working environment. First, the surface roughness model influenced by cutting conditions is constructed based on the experimental results in a turning operation, Second, applying the sliding mode control theory to the turning operation model which is composed of the surface roughness model and the motor transfer function, the surface roughness is closed to the desired value. Finally, the effectiveness of this approach is demonstrated through the computer simulation.

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Comparison of Optimum Drilling Conditions of Aircraft CFRP Composites using CVD Diamond and PCD Drills (CVD 다이아몬드 및 PCD이 드릴을 이용한 항공용 CFRP 복합재료의 홀 가공성 비교)

  • Kwon, Dong-Jun;Wang, Zuo-Jia;Gu, Ga-Young;Park, Joung-Man
    • Composites Research
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    • v.24 no.4
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    • pp.23-28
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    • 2011
  • Recently CFRP laminate joints process by bolts and nets are developed rapidly in aircraft industries. However, there are serious drawback during jointing process. Many hole processes are needed for the manufacturing and structural applications using composite materials. Generally, very durable polycrystalline crystalline diamond (PCD) drill has been used for the CFRP hole process. However, due to the expensive price and slow process speed, chemical vapor deposition (CVD) diamond drill has been used increasingly which are relatively-low durability but easily-adjustable process speed via drill shape change and price is much lower. In this study, the comparison of hole process between PCD and CVD diamond coated drills was done. First of all, CFRP hole processbility was evaluated using the equations of hole processing conditions (feed amount per blade, feed speed). The comparison on thermal damage occurring from the CFRP specimen was also studied during drilling process. Empirical equation was made from the temperature photo profile being taken during hole process by infrared thermal camera. In addition, hole processability was compared by checking hole inside condition upon chip exhausting state for two drills. Generally, although the PCD can exhibit better hole processability, hole processing speed of CVD diamond drill exhibited faster than PCD case.

An Experimental Study on New Type Chip Brakeer(Part 1) (신形 칩折斷具에 관한 實驗的 硏究 (제1보))

  • 손명환;이호철
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.6
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    • pp.1121-1140
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    • 1992
  • In metal cutting the shape of generated chip varies according to cutting conditions, characteristics of workpiece and geometry of cutting tool. The best surface roughness of machined workpiece is obtained when generating flow type contrinuous chip. If the generated chip is not broken, that is not only tangled workpiece and cutting tool, but also may give damage on the machined surface of workpiece or danger for a operator. The flow type continuous chip may bring the low productivity in high speed any heavy cutting, automatic machining process and non-human factory. There are two type of chip break process ; controlling cutting condition and using chip breaker. In present study we carried out the experiment on new type chip breaker compared with conventional type and proved the efficiency of a new type and showed the chip break condition to be applied in actual metal cutting. In the experiment SM 20 C as a workpiece material and WC as a tool material were used and cutting speed of 30-150m/min, feed of 0.071-0.210mm/rev and depth of cut of 1mm were applied as cutting condition. The results of the experiment are as follows : (1) The mechanism of chip curl can be explained more clearly by plastic flow of workpiece material and moment of shearing force. (2) The most effective radius of curled chip and flat distance from cutting edge is 2.0-2.5mm and 1.5mm in both types. (3) The effective inclination angle of chip break surface and side cutting edge angle are 30.deg.- 45.deg. and 20.deg. in conventional type, while the radius of arc surface, lower arc angle A, upper arc angle B and side cutting edge angle are 3mm, 20.deg.- 45.deg., 0.deg.- 45.deg. and 10.deg.- 20.deg. in new type. (4) The probability to be obtained 100% chip breaking ratio is much higher in new type than in conventional type.