共查询到20条相似文献,搜索用时 109 毫秒
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作为微细电火花加工的关键技术之一,微能脉冲电源性能的优劣直接影响放电加工的精度、效率、稳定性等。从减小放电脉冲能量、增大放电间隙、可持续加工的需求出发,探索了一种基于电路共振原理的甚高频(频率在30~300 MHz)微能脉冲电源,突破了现有电火花脉冲电源的工作模式,能产生脉宽极窄、频率极高的脉冲波形,具有纳米级放电蚀除特性,提高了微细电火花加工的极限蚀除能力。放电频率为65 MHz时,相对于传统的微能脉冲电源,加工的孔边缘几乎没有重铸层,极大地减轻了在加工过程中的热损伤、重铸层和热影响区等常规缺陷,改善了工件加工的表面质量,实验结果证明所设计的甚高频微能脉冲电源具有良好的放电蚀除特性。 相似文献
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文中基于新研发的一套微细电火花精密加工系统μEDM-50,介绍了研发过程中探索出的最小脉宽可以达纳秒级的微能脉冲电源以及一些针对微细电火花加工的特点形成的特殊工艺.微能脉冲电源具有主动消电离环节,可以减少脉间的残余电荷放电,提高加工表面质量;特殊工艺有利于提高系统的加工精度和效率,提高微细电极的安全性.最后,介绍了一些金属零件上典型的微小特征精密加工实验以及放电沉积实验.该系统加工特征的尺寸范围主要介于数十微米到数毫米内. 相似文献
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为提高微铣刀磨损在线监测系统的预测精度,尝试通过主成分分析法对微铣削振动信号的时域和频域特征进行降维,将降维后的特征输入改进型BP神经网络模型,实现微铣刀磨损特征分类.结果表明,提出的微铣刀在线监测方法能够准确识别微铣刀的各种磨损状态,此外,和其它分类算法相比,提出的基于遗传算法的BP神经网络模型在分类精度和计算效率方... 相似文献
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文章基于有限元法建立了微径铣刀的欧拉悬臂梁结构动力学模型,求解了不同刀头直径,不同刀头长度和不同刀柄组合的微径铣刀的固有频率,可知随着悬伸长度的减小,固有频率表现出明显的尺度效应。通过计算微径铣刀的振型及变形得知,当悬伸长度相同时,在静态作用力下,随着刀头直径的减小,刀具变形增大;在动态作用力下,刀具变形对微径铣刀的铣削频率和固有频率的平方较敏感,铣削频率离微径铣刀的固有频率越近,刀具变形越大。微径铣刀的动力学变形分析有助于研究微细铣削力、合理选择微细铣削参数、提高铣削过程稳定性,从而获得良好的加工质量。 相似文献
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Taking the minimum chip thickness effect,cutter deflection,and spindle run-out into account,a micro milling force model and a method to determine the optimal micro milling parameters were developed.The micro milling force model was derived as a function of the cutting coefficients and the instantaneous projected cutting area that was determined based on the machining parameters and the rotation trajectory of the cutter edges.When an allowable micro cutter deflection is defined,the maximum allowable cutting force can be determined.The optimal machining parameters can then be computed based on the cutting force model for better machining efficiency and accuracy.To verify the proposed cutting force model and the method to determine the optimal cutting parameters,micro-milling experiments were conducted,and the results show the feasibility and effectiveness of the model and method. 相似文献
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Modelling and analysis of micro scale milling considering size effect, micro cutter edge radius and minimum chip thickness 总被引:6,自引:0,他引:6
Xinmin Lai Hongtao Li Chengfeng Li Zhongqin Lin Jun Ni 《International Journal of Machine Tools and Manufacture》2008,48(1):1-14
This paper presents mechanisms studies of micro scale milling operation focusing on its characteristics, size effect, micro cutter edge radius and minimum chip thickness. Firstly, a modified Johnson–Cook constitutive equation is formulated to model the material strengthening behaviours at micron level using strain gradient plasticity. A finite element model for micro scale orthogonal machining process is developed considering the material strengthening behaviours, micro cutter edge radius and fracture behaviour of the work material. Then, an analytical micro scale milling force model is developed based on the FE simulations using the cutting principles and the slip-line theory. Extensive experiments of OFHC copper micro scale milling using 0.1 mm diameter micro tool were performed with miniaturized machine tool, and good agreements were achieved between the predicted and the experimental results. Finally, chip formation and size effect of micro scale milling are investigated using the proposed model, and the effects of material strengthening behaviours and minimum chip thickness are discussed as well. Some research findings can be drawn: (1) from the chip formation studies, minimum chip thickness is proposed to be 0.25 times of cutter edge radius for OFHC copper when rake angle is 10° and the cutting edge radius is 2 μm; (2) material strengthening behaviours are found to be the main cause of the size effect of micro scale machining, and the proposed constitutive equation can be used to explain it accurately. (3) That the specific shear energy increases greatly when the uncut chip thickness is smaller than minimum chip thickness is due to the ploughing phenomenon and the accumulation of the actual chip thickness. 相似文献
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Ning Liu Martin Loftus Andrew Whitten 《International Journal of Machine Tools and Manufacture》2005,45(10):1152-1161
High speed milling systems are capable of producing complex parts that require little or no hand finishing operations. The machined surfaces are smooth to the touch and they are within the required machining tolerances. However, the visual surface appearance of the parts can be a quality issue because the surface patina is generated by a rotating, multi-flute, ball nose milling cutter as it moves over the surface of the part. Current CAM systems provide good simulating procedures to view the overall surface geometry with swept volume procedures, but they do not consider the micro pattern pertaining to the cutting action of individual cutter flutes. The work presented in this paper addresses this consideration and assesses two new methods to satisfy the need to account for, and predict, the surface machining effects from a ball nose milling cutter. 相似文献
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《CIRP Annals》2022,71(1):65-68
Diamond micro milling of high-quality micro lens arrays suffers from low machining efficiency, due to the inevitable milling marks along tangential feed direction and the slow spiral tool path interpolated by multiple linear axes. In this article, an advanced cutting process is proposed, namely dynamic rotating-tool (DRT) turning, in which a U-axis attachment on a rotary stage is developed to enable synchronous cutter rotation and radial feed motions of a diamond turning tool. This method is experimentally verified and compared with milling, with significantly enhanced surface quality and machining efficiency, thus bringing a new perspective into ultra-precision machining. 相似文献
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In the present work optimal tooth spacing vs spectral redistribution criteria for face milling has been used as one of the methods for vibration control. A special milling cutter with non-uniform pitch has been designed and fabricated and its effect on machine tool vibration is studied. The frequency response spectrum of the machine tool is found out analytically using Finite Element Programme. The spacing between the teeth of milling cutters is found out by minimizing the total power of the relative cutter-workpiece vibration. The newly designed cutter is fabricated and tested experimentally to determine its effectiveness when compared with a standard cutter with evenly spaced inserts. 相似文献
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M.T. Zaman A. Senthil Kumar M. Rahman S. Sreeram 《International Journal of Machine Tools and Manufacture》2006,46(3-4):353-366
In the present day manufacturing arena one of the most important fields of interest lies in the manufacturing of miniaturized components. End milling with fine-grained carbide micro end mills could be an efficient and economical means for medium and small lot production of micro components. Analysis of the cutting force in micro end milling plays a vital role in characterizing the cutting process, in estimating the tool life and in optimizing the process. A new approach to analytical three-dimensional cutting force modeling has been introduced in this paper. The model determines the theoretical chip area at any specific angular position of the tool cutting edge by considering the geometry of the path of the cutting edge and relates this with tangential cutting force. A greater proportion of the helix face of the cutter participating in the cutting process differs the cutting force profile in micro end milling operations a bit from that in conventional end milling operations. This is because of the reason that the depth-of-cut to tool diameter ratio is much higher in micro end milling than the conventional one. The analytical cutting force expressions developed in this model have been simulated for a set of cutting conditions and are found to be well in harmony with experimental results. 相似文献