共查询到20条相似文献,搜索用时 9 毫秒
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针对钛合金钻削过程中的轴线偏斜问题,基于Abaqus对钛合金两种不同的钻削过程进行仿真,建立钻杆的有限元模型、数学模型,并将轴线的偏斜问题转化为两种不同钻削方式的轴向力大小问题。得出结论:在工件速度为180~900 r/min时,钻头与工件同时反向旋转时,轴向力随着工件速度的增大而减小。并对该方式进行工件转速为900 r/min的不同钻头转速、进给量的16组试验,结果表明:在钻头转速为900~1 800 r/min之间、进给量为0.02~0.08 mm/r时,平均轴向力减小了33.4%。因此,可以采用该钻削方式减小偏斜量。 相似文献
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Etienne Gourc Sébastien Seguy Lionel Arnaud 《International Journal of Machine Tools and Manufacture》2011,51(12):928-936
A new dynamical modeling of Active Magnetic Bearing Spindle (AMBS) to identify machining stability of High Speed Milling (HSM) is presented. This original modeling includes all the minimum required parameters for stability analysis of AMBS machining. The stability diagram generated with this new model is compared to classical stability lobes theory. Thus, behavior's specificities are highlighted, especially the major importance of forced vibrations for AMBS. Then a sensitivity study shows impacts of several parameters of the controller. For example, gain adjustment shows improvements on stability. Side milling ramp test is used to quickly evaluate the stability. Finally, the simulation results are then validated by HSM cutting tests on a 5 axis machining center with AMBS. 相似文献
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钻(镗)杆的支架、支承套是深孔钻镗床必备的附件,针对现有支架、支承套存在的半瓦孔径磨损、间隙难以调整导致振动及纵向弯曲等缺点,从液压减振器工作原理出发,采用液压减振技术对钻杆支架、支承套等关键件进行改进改型设计,并通过钻杆支架的合理布局,极大改善了深孔加工工作状态,精度比“双改”前提高两倍以上,实用价值明显。 相似文献
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当飞机着陆下沉速度较快时,油-气式缓冲器因快速压缩会引起缓冲器内部压力剧增和阻尼孔处产生射流现象。为减小缓冲器内部压力和油液流经阻尼孔的流速,以油液入口速度、阻尼孔的孔长、孔径和倒直角为研究对象,通过单因素法对各因素变化引起的缓冲器内压力和流速的变化特性进行分析。通过Fluent软件进行仿真计算,结果表明:油液入口速度越大,缓冲器内部压力和油液流速也越大;孔长对缓冲器内部压力影响较小,对阻尼孔中油液流速影响较大;随孔径减小,缓冲器内压力和阻尼孔中油液流速不断增大;倒直角对缓冲器内压力影响较小,但可降低阻尼孔中的油液流速。研究结果可为缓冲器的优化设计提供参考。 相似文献
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深孔钻床控制系统的钻孔过程采用分段进给的方法,但是在每次钻孔快退之后,下一次工进都会增加一段之前钻孔深度的无效行程,而且随着段数增加而增加,导致实际加工时间和能耗增加一倍,采用行程开关可以解决,但会极大增加钻床系统的复杂程度,并且对不同硬度的材质和钻孔深度效率很低。用PLC的相关指令编写具有计时功能的程序,设计新的控制系统,通过自动记录快退时间与工进安全余量行程所需时间的差值,用该时间设定定时器控制下一次快进的行程,可以很好地解决上述问题。实验调试结果表明:新系统完全满足控制要求,同时有效提高钻孔效率。 相似文献
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针对深孔镗削精加工中高长径比镗杆存在较低的颤振稳定极限,导致容易发生颤振的问题,设计了一种自适应减振镗杆系统。通过调节O形环弹簧的轴向压缩,调谐附加质量阻尼减振器的固有频率,以最大化其动态刚度和适应大范围的长径比;利用电磁激振器和非接触式电容位移传感器自动测量镗杆的频响函数,并通过压缩O形环自适应调谐附加减振器的固有频率;最后,将镗杆频响函数的负实部最小化,以最大限度地提高无颤振切削深度。研究结果表明:安装减振器后镗杆频响函数的实部从-15.17μm/N缩小到-0.24μm/N,相当于动态刚度增大了63.2倍,且表面粗糙度得到明显改善。该系统能够覆盖相当宽的镗杆长径比范围,可适应各种实际安装需求。 相似文献
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基于BTA原理的轴套深孔加工方法 总被引:1,自引:0,他引:1
介绍了基于BTA原理设计的轴套深孔加工方法,即钻杆外冷却、内排屑钻孔法,用于加工直径16~40 mm、深径比在100以内的的深孔。在使用普通车床的卡盘、中间支架和刀架滑板的基础上,设计了一套包括动力头、给液器等装置,解决了轴类零件中心找正、装夹固定、钻头定位和导向等难题,其结构简单,可以方便地在普通车床上使用。并且通过不同的方法组合,也可以用于板类零件加工深孔。给出了详细的加工方法和参数选用,经过实际生产使用表明,该装置运行可靠,操纵维护方便。 相似文献
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针对多数数控系统中深孔加工固定循环指令每次钻深固定不变,导致排屑与加工效率矛盾的不利影响,文章定义了一种钻深可变式深孔加工固定循环G75、G76的格式和规则,规则是:每次钻深随着钻孔深度的增大而依等差级数减小直至最小钻深。该固定循环较好的兼顾了深孔加工的排屑与加工效率问题,有效提高了刀具的耐用度。此外提出了一种运用位运算符编译固定循环G75、G76的方法,这种方法给语法分析以及后续扩充字符、代码检查规则库提供了便利,结合NC代码关键字表,增强了代码编译器的可扩展性和通用性。 相似文献
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Boring and Trepanning Association (BTA) deep hole drilling is used for producing holes with high aspect ratios. In this process, chatter vibration sometimes occurs, and a rifling mark is formed on the bore surface. The rifling mark generating phenomenon is considered to be a result of self-excited vibration caused by time delay. An analytical model is proposed considering the supporting condition of the boring bar in detail. In a real machine for BTA drilling, the boring bar is supported at the oil pressure head and the supporting pad, as well as at the base. The stability of the self-excited vibration is analyzed numerically, and the result is compared with the experiment. The theoretical and experimental results agree well with each other. Furthermore, the effect of an additional guide pad proposed by the authors as a countermeasure is evaluated theoretically and experimentally. 相似文献
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大直径深孔数控强力钻削工艺参数及装备研究 总被引:1,自引:0,他引:1
为了解决某一类大直径深孔的液压锤体的加工问题,在原有的加工方案基础上进行了优化研究,选择了合理钻削的工艺参数,并且设计了相应的装备,达到了降低劳动强度、减小生产成本、提高生产效率的目的. 相似文献
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Maximizing Chatter Free Material Removal Rate in Milling through Optimal Selection of Axial and Radial Depth of Cut Pairs 总被引:2,自引:0,他引:2
Chatter vibrations in milling, which develop due to dynamic interactions between the cutting tool and the workpiece, result in reduced productivity and part quality. Several stability models have been considered in previous publications, where mostly the stability limit in terms of axial depth of cut is emphasized for chatter free machining. In this paper, it is shown that, for the maximization of chatter free material removal rate, radial depth of cut is of equal importance. A method is proposed to determine the optimal combination of depths of cut, so that chatter free material removal rate is maximized. The application of the method is demonstrated on a pocketing example where significant reduction in the machining time is obtained using the optimal depths. The procedure can easily be integrated to a CAD/CAM system or a virtual machining environment in order to identify the optimal milling conditions. 相似文献
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