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金属加工过程中,切削刀具的状态对于生产效率和表面加工质量有重要影响,因此刀具磨损监测具有重要意义。刀具磨损监测是柔性制造系统研究工程的一个重要课题。切削力信号作为加工过程中最稳定和最可靠的信号,和刀具磨损密切相关。从实验上分析切削力与刀具磨损的相关性,提出刀具切削力变化与磨损变化是一致的。基于有限元分析软件对车削加工进行仿真研究,模拟了切削力的大小分布,并将模拟结果与实验结果进行了比较分析,为实际工艺参数的选择提供了理论指导。 相似文献
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508Ⅲ钢材料应用于核岛AP1000蒸发器水室封头中,是一种高强度、高硬度和高断面收缩率的低碳合金钢。硬质合金刀具在切削508Ⅲ钢时,会产生较大的切削力以及切削振动,从而影响刀具使用寿命。本文进行硬质合金刀具铣削508Ⅲ钢试验,探究切削力以及切削振动信号对刀具磨损敏感性的变化趋势的影响,并运用互相关函数分析切削力以及切削振动信号对硬质合金刀具磨损形态的敏感程度。试验结果表明:切削力较切削振动相比,对刀具磨损形态的影响较大,并在切削速度为298m/min时,切削力、切削振动对刀具磨损形态互相关程度较高。为进一步研究通过切削力等信号检测刀具磨损状态提供试验及理论参考。 相似文献
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通过应变式传感器和振动传感器采集力与水平振动信号 ,提取了切削力信号的四阶中心矩和水平振动信号的特征频率谱峰 ,并将模式识别技术应用于刀具状态监测 ,利用感知器算法得到刀具状态的分类函数进行刀具状态识别 ;试验结果表明 ,该方法具有较高的识别精度和较强的抗干扰能力 相似文献
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基于小波变换切削力信号监控PCBN刀具破损的研究 总被引:3,自引:1,他引:3
阐述了小波分析及小波去噪的基本理论,针对傅氏变换和短时傅氏变换的缺点,提出了基于小波变换的切削力信号分析方法。小波多分辨分析能够实现PCBN刀具切削力信号的任意精度与尺度的时一频域分解,从而判断PCBN刀具的切削状态,根据切削力信号的不同特征及时调整切削参数,减少刀具破损的发生,并能够揭示典型切削力信号的分布特征。 相似文献
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In this paper, the finite deformation theory and updated Lagrangian formulation were used to describe the oblique cutting process. Either the tool geometrical location condition or the strain energy density constant was combined with the twin node processing method to act as the chip separation criterion. An equation of three-dimensional tool face geometrical limitation was first established to inspect and correct the relation between the chip node and the tool face. And, a three-dimensional finite-difference heat transfer equation was derived. Based on this approach, tool advancement was achieved in displacement increment step by step from the initial tool contact with the workpiece till the formation of steady cutting force. In this case, a large deformation thermo-elastic–plastic finite element model for oblique cutting was established. The mild steel was used as the workpiece, the tool was P20 and the cutting speed was 274.8 mm/s in this article. The chip deformation process and temperature effect on the strain energy density, chip flow angle, cutting force and specific cutting energy were studied first. Finally, the integrity on machined workpiece surface was explored from the variation of residual stresses and temperature distribution on it after cutting. During the chip deformation process, the chip flow angle obtained by this simulation result was approximately equal to the tool inclination angle, which confirmed with the geometrical requirement of Stabler’s criterion. Besides, the simulated specific cutting energy was compared with the experimental specific cutting energy value, the result of which was within acceptable range. It is obvious from the above findings that the model presented in this paper is consistent with the geometrical and mechanical requirements, which verifies the proposed model is acceptable. 相似文献
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W. J. Deng Q. Li B. L. Li Y. T. He W. Xia Y. Tang 《The International Journal of Advanced Manufacturing Technology》2013,69(5-8):1625-1638
Analysis of cutting force is important in research and development of metal cutting process and in designing cutting tools. This paper reports the theoretical computational formulae for cutting force for cylindrical turning using novel restricted contact tools that have inconstant tool/chip restricted contact length. These formulae are based on the minimum energy principle. The results of extensive cutting tests show that the derived theoretical computational formulae can predict the cutting force, especially the main cutting force, with reasonable accuracy. The novel RC tools-type II and type III can reduce cutting force as well as the conventional RC tools-type I. In addition, they can also effectively control the direction of chip curling, and type III RC tools may have a longer tool life due to the high strength of its cutting edge and the possibility of liquid coolant approaching the cutting zone. Finite element models have been developed to study the cutting force, and the results indicate that the main cutting force can be accurately predicted, while there are some inaccuracies for the feed force and thrust force because of the simplifications adopted during modeling. 相似文献
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Panling Huang Jianfeng Li Jie Sun Jun Zhou 《The International Journal of Advanced Manufacturing Technology》2013,67(5-8):1385-1391
The vibration reduction mechanism of variable pitch end mills was analyzed by the theory of energy balance of the frequency spectrum line. The variable pitch mill can reduce the forced vibration in the cutting process due to the uniform distribution of frequency spectrum line energy and lower peak energy of the cutting force. Aimed at the vibration phenomenon which restricted the efficiency in cutting aero material titanium alloy, high-speed cutting experiments of titanium alloy Ti6Al4V were set with variable and equal pitch mills under dry and down-milling environment. The influences of cutting speeds on cutting forces and tool vibration were analyzed at time domain and frequency domain, respectively, by which the vibration reduction mechanism of variable pitch mill was verified. Due to the misalignment of end mill no. 3, high-level cutting forces and tool vibration were caused by the unequal cutting load on each edge. It is found that severe tool vibration was produced under the cutting speed of 150 m/min because of low-frequency resonance in the cutting process. 相似文献
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Measurements of transient cutting force are often required for analysing transient phenomena in cutting or detecting tool chipping. With most existing tool dynamometers which detect cutting force through strain, however, accurate measurements of transient cutting force cannot be expected because of inadequate frequency characteristics or large time lag. This paper proposes a method of measuring the transient cutting force. In this method, cutting force is calculated by means of a digital Fourier analyser from the output of a tool dynamometer and the transfer function, which has been identified in advance under the same set-up as used for the cutting test. The assessment tests have revealed that the cutting force calculated in this way is extremely close to the real value, regardless of the dynamic rigidity of the tool dynamometer. This method is also applicable for accurate detection of acceleration of a simple system. 相似文献
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Kai Yang Ying-chun Liang Kang-ning Zheng Qing-shun Bai Wan-qun Chen 《The International Journal of Advanced Manufacturing Technology》2011,52(9-12):905-912
The cutting temperature plays an important role in micro-scale cutting process due to the fact that the dimension of the micro-cutter is small and the value of micro-cutter wear is sensitive to temperature. In this paper, the temperature distribution of the micro-cutter in the micro-end-milling process has been investigated by numerical simulations and experimental approach. Micro-end-milling processes are modeled by the three-dimensional finite element method coupling thermal?Cmechanical effects. The micro-cutter cutting temperature distribution, the effect of various tool edge radii on cutting force, and the effective stress during micro-end-milling of aluminum alloy Al2024-T6 using a tungsten-carbide micro-cutter are investigated on. The simulation results show that with increase of tool edge radius the cutting force increases, while the effective stress and mean cutting temperature decreases slightly. In increasing the tool edge radius, the maximum effective stress and cutting temperature region of the micro-cutter occur from the rake face to the corner on the tool edge and the flank face. The tool edge radius has been found to be the major factor affecting micro-cutter temperature distribution. The experimental verification of the simulation model is carried out on a micro-end-milling process of aluminum alloy 2024-T6 with a high-precision infrared camera. The influence of tool edge radius on cutting temperature distribution was verified in experiments. 相似文献
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Yunsong Lian Jianxin Deng Shipeng Li Youqiang Xing Yangyang Chen 《The International Journal of Advanced Manufacturing Technology》2013,67(5-8):1027-1033
WS2 soft-coated tools were produced by medium-frequency magnetron sputtering, multi-arc ion plating, and ion beam-assisted deposition technique on the cemented carbide YT15 (WC?+?15 % TiC?+?6 % Co) substrates. The thickness, microhardness, surface morphologies, crystallization, and coating/substrate critical load of the coatings were tested and investigated. Dry turning tests on no. 45 quenched and tempered steel were carried out with the coated tool and uncoated YT15 tool. Cutting forces and cutting temperatures were tested, respectively. The result shows that the cutting force of WS2 soft-coated tool was decreased by 30–35 %, and the cutting temperature was reduced by 10–15 % in comparison with the uncoated YT15 tool. Through cutting force and cutting temperature theoretical analysis, the lower average shear strength of WS2 soft coating at the tool–chip and tool–workpiece interfaces leads to the decrease of cutting force and cutting temperature during cutting process. The advantage in cutting force and cutting temperature is obvious in relatively high-speed and high-temperature conditions may be because of the high temperature resistance and the oxidation resistance of WS2 soft coating which is not sensitive to high cutting temperature and high cutting speed. 相似文献
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Ching-Yang Lin 《Machining Science and Technology》2020,24(1):65-95
AbstractThis study designed an automatic cutting feed adjustment system for computer numerical control (CNC) turning machine tools, which integrate the operational characteristics of cutting force control and chatter suppression control to shorten the machining time and maintain the quality of workpieces. The setting of appropriate machining conditions (such as cutting feed, spindle speed and depth of cut) to consider both machining quality and efficiency often causes difficulties for machine tool operators. Therefore, this study uses cutting force control to design an automatic cutting feed adjustment method for cutting tools, and then, the chatter suppression control design is used to modify the cutting force command to suppress cutting chatter. The experimental results of the CNC turning machine tool show that the use of the cutting force control to adjust the cutting feed can shorten the machining time; however, the cutting chatter results in larger surface waviness on the workpiece surface. When the cutting force command is properly modified by actuating the chatter suppression control, the workpiece shows better surface roughness with prolonged machining time. Therefore, the cutting tests demonstrate that the proposed system is feasible for satisfying the machining requirements of the manufacturing processes of mechanical parts for high speed and high accuracy. 相似文献
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F. Z. Fang G. X. Zhang 《The International Journal of Advanced Manufacturing Technology》2003,22(9-10):703-707
According to the hypothesis of ductile machining, brittle materials undergo a transition from brittle to ductile mode once a critical undeformed chip thickness is reached. Below this threshold, the energy required to propagate cracks is believed to be larger than the energy required for plastic deformation, so that plastic deformation is the predominant mechanism of material removal in machining these materials in this mode. An experimental study is conducted using diamond cutting for machining single crystal silicon. Analysis of the machined surfaces under a scanning electron microscope (SEM) and an atomic force microscope (AFM) identifies the brittle region and the ductile region. The study shows that the effect of the cutting edge radius possesses a critical importance in the cutting operation. Experimental results of taper cutting show a substantial difference in surface topography with diamond cutting tools of 0° rake angle and an extreme negative rake angle. Cutting with a diamond cutting tool of 0° rake angle could be in a ductile mode if the undeformed chip thickness is less than a critical value, while a ductile mode cutting using the latter tool could not be found in various undeformed chip thicknesses. 相似文献
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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 Vmax being about 260 μ. 相似文献