• Title/Summary/Keyword: Cutting Speed

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Study of Cutting Characteristics in High Speed Synchronized Tapping (고속 동기 탭핑에서의 절삭 특성에 관한 연구)

  • 정용수;이돈진;김선호;안중환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.304-307
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    • 2002
  • High speed machining was accomplished. through the technological advances which covers the whole field of mechanical industry. But tapping have many troubles because of its complicate cutting mechanism, for example. tool damage, chip elimination and synchronization between spindle rotation and feed motion. But High speed tapping is so important that it marches in step with the flow of the times and make improvement in the productivity. In this paper we analyze mechanism of high speed synchronized tapping with the signal of tapping torque and spindle speed obtained through the newly developed high speed tapping machine(NTT-30B). We made an experiment with this machine on condition of various speed from 1000rpm to 10000rpm. As one complete thread is performed through the whole chamfer cutting, cutting torque increases highly in chamfer cutting, but smoothly in full thread cutting functioning of the threads guide. And the size of cutting torque according to spindle speed(rpm) was not enough of a difference to be conspicuous.

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A Study on the Evaluation on High-speed Machining Characteristics of AL7075 (AL7075의 고속가공특성 평가)

  • 이종현;이동주;이응숙;신보성
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.10a
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    • pp.220-224
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    • 2001
  • High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feedrate, high-speed machining can give great advantages for the machining of dies and molds. To perform efficient high-speed machining, evaluation of high speed machinability must be studied preferentially and it can be identified by investigation of cutting force. To measure cutting force in high-speed machining, dynamometer has to have high natural frequency. In this paper, The dynamometer which has high natural frequency used to measure the cutting force in various cutting conditions. High-speed machining characteristics are evaluated by the cutting force, FFT analysis of the cutting force and chip formation.

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The Effect of the Cutting Parameters on Performance of WEDM

  • Tosun, Nihat
    • Journal of Mechanical Science and Technology
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    • v.17 no.6
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    • pp.816-824
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    • 2003
  • In this study, variations of cutting performance with pulse time, open circuit voltage, wire speed and dielectric fluid pressure were experimentally investigated in Wire Electrical Discharge Machining (WEDM) process. Brass wire with 0.25 mm diameter and AISI 4140 steel with 10 mm thickness were used as tool and work materials in the experiments. The cutting performance outputs considered in this study were surface roughness and cutting speed. It is found experimentally that increasing pulse time, open circuit voltage, wire speed and dielectric fluid pressure increase the surface roughness and cutting speed. The variation of cutting speed and surface roughness with cutting parameters is modeled by using a regression analysis method. Then, for WEDM with multi-cutting performance outputs, an optimization work is performed using this mathematical models. In addition, the importance of the cutting parameters on the cutting performance outputs is determined by using the variance analysis (ANOVA).

Feedrate Scheduling for High Speed Machining Based on an Improved Cutting Force Model (향상된 절삭력 모델을 이용한 고속 가공의 이송속도 스케줄링)

  • 이한울;고정훈;조동우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.141-144
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    • 2003
  • This paper proposes an analytical model of off-line feed rate scheduling to obtain an optimum feed rate for high speed machining. Off-line feed rate scheduling is presented as an advanced technology to regulate cutting forces through change of feed per tooth, which directly affects variation of uncut chip thickness. In this paper, the feed rate scheduling model was developed using a mechanistic cutting force model using cutting-condition-independent coefficients. First, it was verified that cutting force coefficients are not changed with respect to cutting speed. Thus, the feed rate scheduling model using the cutting-condition-independent coefficients can be applied to set the proper feed rates for high speed machining as well as normal machining. Experimental results show that the developed fred rate scheduling model makes it possible to maintain the cutting force at a desired level during high speed machining.

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Tool Wear in High Speed Face Milling Using CBN Tool (CBN 공구를 이용한 고속 정면밀링시의 공구마멸)

  • 최종순
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.332-338
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    • 2000
  • The high speed machining is now one of the most effective manufacturing methods to achive higher productivity. However, due to the increased cutting temperatures caused by increased cutting speed, tool wear become larger. Especially in high speed face milling, cutting tools are exposed not only to high cutting temperatures, but also to mechanical and thermal shock stresses. It is essential, therefore, to know the wear characteristics of tool materials in high speed machining. This study presents an experimental investigation of the cutting performance of CBN tools in high speed face milling of gray cast iron FC25. The effect of cutting conditions and cutting length on flank wear of CBN tools and roughness of machined surfaces is investigated. The cutting parameters involved were ; cutting speeds in the range of 600to 1800 m/min, feed of 0.1 mm/tooth, and depth of cut of 0.3mm.

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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, Kwang-Lae;Ryu, Bong-Hwan
    • 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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A Study on the Cutting Surfaces in CNC Plasma Cutting of high tensile steel plate (고장력 강판의 CNC Plasma 절단시 절단면에 관한 연구)

  • 김인철;김성일
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.149-154
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    • 2003
  • The cutting tests of high tensile steel plate(AH36) were carried out using CNC plasma arc cutting machine. Both top and bottom width of kerf and the surface roughness(Ra, Rmax) of cut surface are measured under various cutting conditions such as cutting speed, steel plate thickness, etc. In the CNC plasma arc cutting, the surface roughness decreases as cutting speed increases. The hardness is high up to 4mm depth from the cutting surface. In the cutting speed 1300~2100mm/min, the ratio of proper kerf width(Wt/Wb) is around 2.6. Through the series the series of experiments, the satisfactory cutting conditions of high tensile steel plate were found.

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High Speed Milling of Titanium Alloy (Ti 합금의 고속가공시 밀링특성에 관한 연구)

  • Chen, Ming;Lee, Young-Moon;Yang, Seung-Han;Jang, Seung-Il
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.5
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    • pp.34-39
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    • 2003
  • The paper will present chip formation mechanism and surface integrity generation mechanism based on the systematical experimental tests. Some basic factors such as the end milling cutter tooth number, cutting forces, cutting temperature, cutting vibration the chip status, the surface roughness, the hardness distribution and the metallographic texture of the machined surface layer are involved. The chip formation mechanism is typical thermal plastic shear localization at high cutting speed with less number of shear ribbons and bigger shear angle than that at low speed, which means lack of chip deformation. The high cutting speed with much more cutting teeth will be beneficial to the reduction of cutting forces, enlarge machining stability mot depression of temperature increment anti-fatigability as well as surface roughness. The burrs always exist both at low cutting speed and at high cutting speed. So the deburring process should be arranged for milling titanium alloy in my case.

Simultaneous Control of Cutting Force and Position Using Two Degree-of- Freedom Controller in CNC Ball-end Milling Process (2자유도 제어기를 이용한 CNC볼엔드밀링 공정에서 절삭력과 위치의 동시제어)

  • 양호석;심영복;이건복
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.04a
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    • pp.536-542
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    • 2002
  • There are two important variables in machining process control, which are feed and cutting speed. In this work, a two degree-of-freedom controller is designed and implemented to achieve on-line cutting force control and position control based on the modelling of cutting process dynamics which are established through step response test. Two schemes are proposed and implemented. The first is feed control under the constant spindle speed and spindle speed control under the constant feed speed. The second is a simultaneous control of feed and spindle speed. The last performs a position control under the constant cutting force. Those are confirmed to work properly. Especially the latter shows a faster response.

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Cutting Force Control Using A Two Degree-of-Freedom Controller in Ball-end Milling Processes (CNC 볼엔드밀링 공정에서 2자유도 제어기를 이용한 절삭력 제어)

  • 양호석;심영복;이건복
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.219-224
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    • 2002
  • There are two important variables in machining process control, which are feed and cutting speed. In this work, a two degree-of-freedom controller is designed and implemented to achieve on-line cutting force control based on the modelling of cutting process dynamics which are established through step response test. Two schemes are proposed and implemented. The first is feed control under the constant spindle speed and spindle speed control under the constant fled speed. The second is a simultaneous control of feed and spindle speed. Those are confirmed to work properly. Especially the latter shows a faster response and we'll be evaluated to pare away workpiece by simultaneous control of position and cutting farce sooner or later.

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