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绿色切削高强度钢的刀具磨损及切屑形态 总被引:5,自引:0,他引:5
分析了微量润滑切削时润滑剂的渗透机理及润滑作用对铣削力的影响。使用传统切削、干式切削及微量润滑三种方式铣削高强度钢(PCrNi3Mo),对比切削性能并探讨微量润滑技术对刀具磨损及切屑形貌的影响。对微量润滑加工过程中切削参数(铣削速度、每齿进给量、铣削深度及润滑剂使用量)对刀具磨损的影响进行研究,利用响应曲面法建立了刀具后刀面磨损模型以确定铣削高强度钢(PCrNi3Mo)时润滑剂的最佳使用量,并利用试验验证。结果表明,微量润滑可有效抑制刀具磨损进程;建立的刀具后刀面磨损模型与试验结果误差较小,具有较高实用价值,微量润滑铣削材料PCrNi3Mo时,润滑剂的最佳使用值约为185mL/h;通过改善切削区的摩擦情况,微量润滑可降低切削区域温度并有效控制切屑形貌。 相似文献
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为研究AlCoCrFeNi高熵合金的铣削性能,利用有限元技术结合单因素仿真试验进行研究,分析不同主轴转速、铣削深度以及进给速度对AlCoCrFeNi高熵合金加工过程的主铣削力、切削区域切屑、刀具最高温度以及切削区最大等效应力的影响。试验结果表明:铣削深度对AlCoCrFeNi高熵合金加工的主铣削力以及最大有效应力影响较小;进给速度对AlCoCrFeNi高熵合金加工的切削区域切屑和刀具的最高温度影响较小。因此,有必要对AlCoCrFeNi高熵合金机械加工方面进行理论研究。 相似文献
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钛合金高速旋转超声椭圆振动侧铣削切屑特征和刀具磨损研究 总被引:1,自引:0,他引:1
难加工材料钛合金在采用传统铣削方式时,随着切削速度的增加,切削力和切削温度都迅速增加,使得切削条件恶化并加速刀具磨损,从而导致刀具过早失效。将超声椭圆振动加工技术引入到高速铣削中,进行了钛合金高速旋转超声椭圆振动侧铣削试验。从切屑特征以及刀具后刀面磨损两个方面研究了高速超声椭圆振动铣削参数匹配对钛合金加工的影响。首先基于高速超声椭圆振动铣削过程中刀具-工件的运动学特点推导出高速超声椭圆振动铣削加工参数与振动参数间的匹配关系,然后利用本实验室自行研制的超声椭圆振动铣削装置进行了不同参数匹配关系下的验证性切削试验。试验结果表明:合理的参数匹配使得超声椭圆振动铣削在高速条件下依然能够实现分离型断续切削加工。相比普通铣削加工,分离型的高速超声椭圆振动铣削能够获得更加微细的切屑,切削热能够被及时地带走;良好的切削条件使得刀具的后刀面磨损均匀而缓慢,从而延长刀具的使用寿命;高速超声椭圆振动铣削能够有效地提高生产效率。 相似文献
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针对铁基高温合金GH2132高速加工时铣削力大、加工质量不稳定的特点,采用新型涂层硬质合金刀具进行高速干铣削试验,研究切削参数对铣削力及加工表面粗糙度的影响规律。运用极差分析法并根据泰勒公式、正交试验数据和回归分析得出拟合公式,结果表明:对铣削合力峰值影响较大的切削因素是轴向切削深度和径向切削深度;对加工表面粗糙度影响较大的因素是每齿进给量和轴向切削深度。当vc=50-100m/min、fz=0. 08-0. 10mm/z、ap=0. 2-0. 3mm、ae=3-4mm时,可以获得较小的铣削力和表面粗糙度,且拟合公式可以有效预测加工过程中铣削力和表面粗糙度值。本文对探究刀片磨损机理及提高表面加工质量提供了参考数据。 相似文献
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研究了面铣刀的主偏角对切屑厚度和每齿进给量的影响,铣削中每齿进给量的决定因素,切削宽度与刀具直径的比值对切屑厚度的影响等问题进行理论分析,同时结合变速箱壳体铣削加工过程进行验证,解决了合理选择铣刀及切削参数以提升加工效率的问题。 相似文献
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尺度效应是微切削工艺中的一种特殊现象,通常用最小未变形切屑厚度来判定尺度效应发生的临界点。为了更好地理解微细铣削的切削机理,对铣刀钝圆半径与尺度效应之间的关系进行深入研究是有必要的。由于在铣削加工过程中,刀具大多数为径向进给,侧刃为主要切削刃,因此这里对仅有侧刃参与切削的情况进行了仿真与试验研究。通过对仿真中切屑形貌与试验中表面粗糙度的分析,分别确定了仿真与试验的最小未变形切屑厚度值。仿真与试验结果表明,微细铣削的两种工艺方式对最小未变形切屑厚度的影响有限,最小未变形切屑厚度为(0.28~0.40)倍的铣刀钝圆半径。同时,工件的材料属性对刀具侧刃的最小未变形切屑厚度有一定的影响。本研究可以用于指导微细铣削加工中对于不同刀具钝圆半径及工件材料加工参数的选择和量化,提高工件加工质量具有重要参考价值。 相似文献
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根据高速雕铣机石墨加工的特殊性,以及现役高速机中因没有采用更好的过滤装置,而导致粉尘飞扬的不足,结合数控机床本身的特性,设计出一套全自动石墨过滤装置及水帘冷却装置,达到非常好的效果,可实现任意排渣,机床加工绿色环保,提高了加工效益。 相似文献
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WANG Chengyong ZHOU Li FU Hao HU Zhouling 《机械工程学报(英文版)》2007,20(4):27-31
Graphite becomes the prevailing electrode material in electrical discharging machining (EDM)currently.Orthogonal cutting experiments are carried out to study the characteristics of graph- ite chip formation process.High speed milling experiments are conducted to study tool wear and cutting forces.The results show that depth of cut has great influence on graphite chip formation.The removal process of graphite in high speed milling is the mutual result of cutting and grinding process. Graphite is prone to cause severe abrasion wear to coated carbide endmills due to its high abrasive- ness nature.The major patterns of tool wear are flank wear,rake wear,micro-chipping and breakage. Cutting forces can be reduced by adoption of higher cutting speed,moderate feed per tooth,smaller radial and axial depths of cut,and up cutting. 相似文献
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Dehong Huo Chao Lin Kenneth Dalgarno 《The International Journal of Advanced Manufacturing Technology》2014,72(5-8):943-953
Industrial applications of the micro milling process require sufficient experimental data from various micro tools. Research has been carried out on micro milling of various engineering materials in the past two decades. However, there is no report in the literature on micro milling of graphite. This paper presents an experimental investigation on micro machinability of micro milling of moulded fine-grained graphite. Full immersion slot milling was conducted using diamond-coated, TiAlN-coated and uncoated tungsten carbide micro end mills with a uniform tool diameter of 0.5 mm. The experiments were carried out on a standard industrial precision machining centre with a high-speed micro machining spindle. Design of experiments (DoE) techniques were applied to design and analysis of the machining process. Surface roughness, surface topography and burrs formation under varying machining conditions were characterized using white light interferometry, SEM and a precision surface profiler. Influence of variation of cutting parameters including cutting speeds, feedrate and axial depth of cut on surface roughness and surface damage was analysed using ANOVA method. The experimental results show that feedrate has the most significant influence on surface roughness for all types of tools, and diamond tools are not sensitive to cutting speed and depth of cut. Surface damage and burrs analysis show that the primary material removal mode is still brittle fracture or partial ductile in the experimental cutting conditions. 3D intricate micro EDM electrodes were fabricated with good dimensional accuracy and surface finishes using optimized machining conditions to demonstrate that micro milling is an ideal process for graphite machining. 相似文献
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Kyung-Hun Lee Jung-Min Lee Dae-Won Hwang Byung-Min Kim 《Journal of Mechanical Science and Technology》2013,27(3):849-856
We investigated the extrusion behavior of mechanically alloyed Zn-22wt%Al powders with different lubricants and green-compact shapes. The mechanical alloying of powder particles was performed by planetary ball milling for 4 h, 8 h, 16 h, 32 h, and 64 h. The mechanical properties of these powders, as compacted and sintered cylindrical preforms, were estimated by uniaxial compression tests. The alloyed powder with an average particle size of 10 μm obtained after milling for 32 h had the highest compressive strength (288 MPa). Extrusions of miniature spur gears with pitch circles of 1.8 mm using the alloyed powder were carried out at different extrusion temperatures. An extrusion temperature of 310°C resulted in the highest Vickers hardness without surface defects when alloyed powder milled for 32 h was used. To investigate the effect of green-compact shape and lubricant on the dimensional accuracy and cracking regions during the first stage of hot extrusion, extrusion experiments with conical- or cylinder-type green compact shapes and BN spray or a graphite lubricant were performed at an extrusion temperature of 310°C. The results showed that the extrusion of spur gears by using the conical-shaped billet and graphite lubricant resulted in a low extrusion load, good surface roughness, a short cracking region during the first stage, and high dimensional accuracy. 相似文献
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Muhammad Pervej Jahan Mustafizur Rahman Yoke San Wong 《The International Journal of Advanced Manufacturing Technology》2011,53(1-4):167-180
Present study investigates the feasibility of improving surface characteristics in the micro-electric discharge machining (EDM) of cemented tungsten carbide (WC?CCo), a widely used die and mould material, using graphite nano-powder-mixed dielectric. In this context, a comparative analysis has been carried out on the performance of powder-mixed sinking and milling micro-EDM with view of obtaining smooth and defect-free surfaces. The surface characteristics of the machined carbide were studied in terms of surface topography, crater characteristics, average surface roughness (R a) and peak-to-valley roughness (R max). The effect of graphite powder concentration on the spark gap, material removal rate (MRR) and electrode wear ratio (EWR) were also discussed for both die-sinking and milling micro-EDM of WC?CCo. It has been observed that the presence of semi-conductive graphite nano-powders in the dielectric can significantly improve the surface finish, enhance the MRR and reduce the EWR. Both the surface topography and crater distribution were improved due to the increased spark gap and uniform discharging in powder-mixed micro-EDM. The added nano-powder can lower the breakdown strength and facilitate the ignition process thus improving the MRR. However, for a fixed powder material and particle size, all the performance parameters were found to vary significantly with powder concentration. Among the two processes, powder-mixed milling micro-EDM was found to provide smoother and defect-free surface compared to sinking micro-EDM. The lowest value of R a (38?nm) and R max (0.17???m) was achieved in powder-mixed milling micro-EDM at optimum concentration of 0.2?g/L and electrical setting of 60?V and stray capacitance. 相似文献
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NOMEX蜂窝芯高速铣削加工工艺的优化 总被引:1,自引:0,他引:1
为了解决NOMEX蜂窝芯高速铣削加工过程中固持可靠性差和加工效率低以及加工表面质量差的问题,提出一种新的基于强磁场和摩擦学原理的蜂窝芯高速加工固持方法。该方法利用灌入蜂窝孔中的铁粉自重以及强磁场平台对铁粉产生的吸引力,在铁粉与蜂窝孔侧壁之间以及蜂窝、铁粉与固持平台之间产生摩擦力,实现对蜂窝底部的全约束和固定。建立了NOMEX蜂窝芯高速铣削加工的铣削力模型,进行了以铣削力最小为目标的铣削参数的优化。通过铣削参数的优化,保证了加工过程中蜂窝的固持稳定性,同时保证了蜂窝加工效率和加工质量。 相似文献