工具杆几何尺寸对超声扭转振动系统的影响

1引言 随着功率超声技术的不断发展,超声加工技术应用范围也越来越广,如超声振动切削、超声钻孔、超声焊接、超声研磨和抛光以及超声金属塑性材料加工等,日益受到人们的重视.在这些超声加工应用技术中,除了利用纵向超声振动系统外,扭转振动以及纵-扭复合振动系统也具有很大的发展潜力.超声加工过程中通常是通过在换能器的变幅杆端加载工具杆来对材料进行处理的,因此,必须考虑工具杆对振动系统的影响.为此,一些文献[1～5]对此进行了研究,但基本上只涉及了纵向振动系统.对于扭转超声加工振动系统中工具杆对系统振动特性的影响研究甚少,几乎未见此方面的报道.本文主要利用四端网络理论和机电类比方法对扭转超声加工振动系统的共振频率随工具杆的截面积与长度的变化规律进行了有益探讨,结果表明,理论和实验比较地一致,为超声扭转加工振动系统的设计提供了参考依据.     

功率超声在微型车缸体加工中的应用

文中介绍了已研制成功的DY90摩托车铸铁缸体超声振动珩磨系统的应用效果，论述了该系统的原理及结构特点。该项技术还可推广应用于微型汽车的铸铁缸体，为铸铁缸体珩磨开创了一条高效、高质、低耗的新途径。     

纵—扭复合振动模式超声变幅杆研究

本文对窄端带有均匀截面直棒的指数型纵-扭复合振动模式超声变幅杆进行了理论及实验研究,推出了该复合模式变幅杆纵向振动及扭转振动的共振频率方程。为了克服同一变幅杆纵向与扭转振动很难实现同频共振的问题,提出了一种通过改变指数型变幅杆的截面变化规律而实现改变纵向及扭转振动传播速度的方法。通过合理选择指数变幅杆的截面半径减缩系数(即参数β),实现了纵-扭复合变幅杆纵向振动与扭转振动的同频共振。实测结果表明,共振频率的理论值与测试值基本一致,变幅杆纵向及扭转振动共振频率的测试值也比较符合。该变幅杆具有比较高的位移放大系数。可望应用于超声加工、超声疲劳实验及超声焊接等功率超声技术中。     

超声珩磨作用下单双空化泡振动系统动力学对比分析

针对超声珩磨加工过程中空化泡的振动预测及现有理论模型的局限性,将空化泡泡内气体的膨胀视为等温过程,压缩视为绝热过程,修正了超声珩磨下单、双空化泡的动力学模型。利用四阶龙格库塔方法分别对超声珩磨和超声两种条件下单、双空化泡的振动特性进行了数值计算,并讨论了声压幅值、超声频率、磨削液静压力及泡内含气量对单、双空化泡振动的影响。结果发现,超声珩磨要比超声作用下单、双空化泡的膨胀幅值更低、溃灭时间更短、泡壁溃灭速度更小;声压幅值和磨削液静压力都存在某一临界值,可用于区分磨削液单、双空化泡的应用范围;通过铝箔腐蚀法观察到磨削液单个空蚀坑体积要大于两相邻的空蚀坑,间接验证了理论模型的合理性。     

微超声振动细胞切割系统中变幅杆的分析与设计

针对细胞微超声振动切割系统对超声变幅杆的要求,将等截面圆柱形阶梯变幅杆的一端替换成圆锥形变幅杆构成一种复合圆锥阶梯形变幅杆。由任意变截面杆纵向振动的波动方程出发,推导了复合圆锥阶梯形变幅杆的基本理论参量,设计了超声变幅杆的基本结构,给出其制造尺寸。并应用有限元法对变幅杆进行了模态分析,得到了共振频率和位移节点等重要参数。     

大直径超声变幅杆端面振幅的分布与影响因素

应用有限元分析软件ANSYS对大直径的纵向超声变幅杆进行振动特性研究。分析变幅杆大端面振幅的分布状况以及变幅杆直径、变幅杆长度、两端面直径比对其影响,发现其具有较复杂的振动分布,并总结一些相关规律。     

一种具有多工具头的超声换能振动系统

研究了一种新的超声波振动打孔系统.该系统由超声换能器、变幅杆、弯曲振动棒以及多工具头组成.与传统的单工具头超声波打孔装置相比.多工具头打孔装置具有工作效率高、换能器发热小等优点.文中给出了振动系统各部分的频率设计公式以及整体共振频率的计算公式.实验表明,振动系统各部分共振频率的设计值与测量值基本符合.多工具头超声振动系统的实用工作性能比较理想.     

超声变幅杆与杯型工具一体化设计

基于细长杆纵振理论和薄圆盘振动理论,针对超声变幅杆与杯型工具开展一体化设计研究。通过分析各段的振动模态,将超声变幅杆和杯型工具的振动分为"纵-弯-纵"三个部分,分别建立三段位移和应力函数及边界条件,推导得出超声变幅杆和杯型工具的总体频率方程。根据得到的总体频率方程,设计出典型的超声变幅杆和杯型工具。对所设计的超声变幅杆和杯型工具的振动性能进行有限元分析和试验测试,分析和试验结果表明,超声变幅杆和杯型工具谐振频率的设计结果和有限元分析及测试结果的误差均在10%以内,验证了所建立的超声变幅杆和杯型工具的频率方程的正确性,并分析了各段长度和半径对超声变幅杆和杯型工具谐振频率的影响规律,为其谐振频率的修正提供了依据。     

A8 功率超声振动系统研究进展

Ａ８功率超声振动系统研究进展程存弟，贺西平（陕西师范大学应用声学研究所西安·７１００６２）功率超声振动系统是指由换能器、变幅器（或传振杆）和工具头（或幅射器）等组成的功率超声产生系统，是功率超声技术的核心部分。在功率超声技术的传统应用中大多采用一维纵...     

超声珩齿振动系统的设计方法及其动力学特性

超声辅助珩齿是一项应用前景良好的齿轮精加工方法,其振动系统的设计是关键技术之一。分析了变幅杆和齿轮振动时的耦合关系,对振动系统做了合理简化。在此基础上,结合边界条件,提出一种新的振动系统设计方法,并利用它设计了变幅杆,分析了变幅杆和齿轮的动力学特性。通过与有限元分析及试验结果比较,说明所提出理论模型是完全合理可行的,实例计算结果比有限元分析结果更接近实测值。所获得的结论对超声珩齿振动系统的设计有一定的指导意义。     

超声珩齿振动系统动力学特性分析与仿真

为研究超声珩齿振动系统的非谐振设计,通过MATLAB软件对振动系统的动力学频率方程进行求解,分析了变幅杆设计长度和变幅器振动频率对频率方程解误差的影响,并得出一组变幅器的设计参数。为验证非谐振设计方法的可行性,通过ANSYS模态分析,能使变幅器的谐振频率与理论设计的结果基本一致。     

Improved magnetorheological honing process for nanofinishing of variable cylindrical internal surfaces

Improved magnetorheological honing process is developed for nanofinishing of variable cylindrical internal surfaces with better surface integrity. In the present work, finishing performance of existing magnetorheological honing process is enhanced. The present improved process consists magnetorheological honing tool having curved permanent magnet end surfaces. When magnetic field is analyzed using Ansoft Maxwell, the improved magnetorheological honing process results in uniform and higher magnitude of magnetic flux density over its magnetic tool curved end surfaces as compared to the tool having magnetic flat end surfaces. Therefore, an improved magnetorheological honing process has been developed with tool having curved permanent magnet end surfaces. During experimentation, surface roughness values Ra, Rq, and Rz get decreased by 76.28%, 76.67%, and 75.20%, respectively, with improved magnetorheological honing tool having curved end magnetic surfaces, while 47.97%, 46.24%, and 47.08% decreased with tool having flat end magnetic surfaces in same 60 minutes of finishing time. This results in enhancement of finishing performance of the present improved magnetorheological honing process in terms of reduced finishing time and ability to produce good surface integrity. Hence, the present improved magnetorheological honing process performance with tool having curved end magnetic surfaces is found as comparatively better than the finishing tool having flat end permanent magnetic surfaces.     

Tribological properties of twin wire arc spray coated aluminum cylinder liner

The effects of honing process on the friction and wear behaviors of Twin Wire Arc Spray (TWAS) coated aluminum cylinder liners were investigated using a pin-on-reciprocating type of a tribotester. Two types of coated cylinder liners were prepared for the tests: Type I — smooth honing (SH) with ~ 40° honing angle, and Type II — helical structure honing (HSH) with ~ 140° honing angle. The aluminum cylinder liners were coated with an Fe0.8C wire by the TWAS process. In un-lubricated condition, Type II specimen showed lower coefficient of friction (COF) compared to Type I specimen. This result was due to the fact that the groove of Type II was sufficiently large to trap the wear particles that may otherwise contribute to three body abrasive wear. In lubricated condition, Type I showed lower COF due to its lower roughness in comparison to Type II. The experimental results indicate that TWAS process can be effectively utilized for engine applications in conjunction with optimum honing process for the cylinder liner.     

Numerical analysis and experimental validation of surface roughness and morphology in honing of Inconel 718 nickel-based superalloy

Honing is an important technology for machining onboard system parts. The parts are usually made of difficult-to-machining materials, e.g., Inconel 718 superalloy. Honing can improve the finishing accuracy and surface quality. However, the selection of the honing parameters was primarily based on the results of a large number of experiments. Therefore, the establishment of a reliable model is needed to predict the honed surface roughness and morphology, and offers a theoretical direction for the choice of parameters. In the present study, a numerical simulation model was constructed for analysis of the honing process by Python. The oilstone, workpiece surface morphology and motion trajectory were discretized by Python, and the machined surface was obtained by trajectory interference. Firstly, based on the statistical analysis of the surface topography of oilstone, the shape of grains was simplified and the surface topography of oilstone was built accordingly. Then, the initial surface morphology of the workpiece was constructed and the trajectory of grains on the workpiece surface was analyzed, which showed the distribution of the removed material. Meanwhile, the plastic deformation of material was analyzed in the simulation model. The critical depth of three stages of contact between grains and workpiece was calculated by the theoretical formula: scratching, ploughing and cutting. By analyzing the distribution of bulge, the plastic deformation in ploughing and cutting stage was studied. Further, the simulated results of honed surface roughness and morphology were validated and agreed reasonably well with the honing experiment. Finally, the effects of honing process parameters, including grain size, tangential speed, axial speed, radial speed and abrasive volume percentage, on the surface roughness of the workpiece were analyzed by the simulation model. The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00422-0     

A novel magnetorheological honing process for nano-finishing of variable cylindrical internal surfaces

A novel magnetorheological honing process is designed and developed for nano-finishing of cylindrical internal surfaces with the help of permanent magnets. The radial movement of magnetic tool surface is adjusted as per the internal diameter of different cylindrical components and make it fixed before start of finishing so that it can maintain constant working gap while perform finishing. The present developed magnetic tool surface always constitutes higher magnetic field than the inner surface of ferromagnetic or non-ferromagnetic cylindrical workpiece. This is an important requirement to finish the internal surface of ferromagnetic or non-ferromagnetic cylindrical components because it ensures MR polishing fluid cannot stick on the workpiece surface while performing the finishing. Hence, present developed process is useful for finishing of ferromagnetic cylindrical molds, dies, hydraulic actuators, etc. for its better functional applications after the conventional honing or grinding process. The internal surface roughness of cylindrical ferromagnetic workpiece is dropped to 90?nm from its initial value of 360?nm in 100 minutes of finishing. Further scanning electron microscopy has also been done to understand the surface characteristics of finished workpiece. The results revealed that the developed magnetorheological honing process is capable to perform nano-finishing of internal surface of the ferromagnetic cylindrical components.     

Effects of thermoelastic stress during honing on component dimensions

Equations are given for the temperature distribution and thermoelastic deformations arising in the workpiece and tool during honing, as well as a method for determining the corrections for the temperature errors to adjusting automatic-control devices.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 30, No. 6, pp. 1119–1126, June, 1976.     

Process Performance Comparison of ECH and PECH for Quality Enhancement of Bevel Gears

This paper presents a comparative analysis of constant-current electrochemical honing (ECH) and pulsed electrochemical honing (PECH) for quality enhancement of straight bevel gears. The quality of straight bevel gears after finishing by ECH and PECH is compared focusing on tooth flank finish and microgeometry. Tooth flank finish was evaluated in terms of percentage enhancement in average roughness value, maximum roughness value, and 5-point roughness value. Percentage enhancements in pitch error, pitch variation error, accumulated pitch error, and total runout were used to evaluate the microgeometry of the bevel gears. It was found that the PECH process is capable of simultaneously enhancing the tooth flank finish and microgeometry of bevel gears by more than 50% as compared with ECH-finished bevel gears. The PECH-finished gears also exhibited superior microstructure as compared with ECH-finished gears. These improvements will enhance the service life and working performance of gears.     

A new magnetorheological finishing process for ferromagnetic cylindrical honed surfaces

In today’s industries, the internal surface finishing of cylindrical objects is highly demanded to improve their functional performance in various engineering applications. During the traditional honing operation, the finishing forces produced by abrasives on the workpiece surface are not easily controllable and also produce various surface defects. Therefore, to further improve the surface integrity of the traditionally cylindrical honed surface made of ferromagnetic or non-ferromagnetic materials, a new magnetorheological (MR) finishing process has been used with a controlled magnetic field. The experimentation is performed on the honed surface made of gray cast iron, which is generally used as a cylinder liner. The percentage change in surface roughness values, i.e., Ra, Rq and Rz, reduced by 77.44%, 70.16% and 72.16%, respectively, with better improvement in surface after 90 minutes of finishing. The experimental results demonstrated the effectiveness of present process for improving the functional applications of ferromagnetic cylindrical honed surface after removing the various surface defects such as deeper grooves, honing grooves with shaper edges, torn and folded metals, and cavities or holes. The applications of new MR finishing process can also be useful in the internal finishing of injection barrel of a molding machine, cylindrical molds and dies, hydraulic cylinder, etc.