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研究在高硬度钢中攻丝的转力距Baolin Yinand Rongdi Han中华人民共和国，哈尔滨技术学会机械工程和自动化部，哈尔滨150001摘要：在这要解决攻丝中的震动这一问题，因为高速钢是很难在50HRC硬度的工件上攻丝M3孔的。理论上的分析用破碎技巧指出在细工品上攻丝的冲击效果造成增加的 2 类型的压迫力强度因素和大面积的微裂缝，使得降低塑料的毁坏, 减少切削力和降低攻丝转力矩，而且攻丝的扭转力提高了如在动态分析所证明的震动。实验的结果表示与选择良好的广阔面, 攻丝转力矩减少，同时震动频率增加, 而且当切削的时间比增加攻丝转力矩增加, 此时切削计时更重要影响攻丝转力矩。 攻丝的震动然后被证明在硬度高的钢中攻丝小孔是对问题的实际解决办法。关键词：攻丝震动，硬度高的钢，微裂缝，攻丝扭矩，高扭矩1、 概述 在硬度45HRC的钢 中攻丝(M3) 的孔是一件非常困难的工作。硬度 0.45% C 钢有高强度(b1700?MPa) 和在这些材料中攻丝M3转力矩大约 1.3Nm。因此，攻丝破坏似乎是程序的主要问题之一, 也可能是由于过大的转力矩。被硬化的钢拥有高坚硬, 很象高速钢(HSS) 攻丝。它总是使机器制造麻烦譬如工具穿戴和钻孔。高攻丝的扭矩结果在其它问题联系了攻丝的振动噪音包括螺纹尺寸准确性和螺纹形状错误。很明显, 常规过程不能实现小孔的要求攻丝高硬度的钢的攻丝强度、硬度和扭转力强度。但是, 以现代制造业技术的迅速发展, 譬如航空器和航天飞机, 一些组分需要在熄灭以后攻丝, 考虑几何准确性和表面力量。总的, 用机器探测高硬度钢的成分是研究的方向。 振动切口技术是50 年前由Kumabe 提出的有各种各样的作用, 即减少切口力量, 改进表面质量, 克制的工具穿戴, 等等。攻丝震动向钛合金和其它材料被申请增加攻丝的效率和减少攻丝的整体扭矩。攻丝在不同的材料在不同的处理条件下对振动有许多贡献。 张制造了一个由振动协助的攻丝设备, 在由一台压电作动器被使用引起振动沿攻丝轴以50-1600 赫兹和高度频率0.1-5微米。这说明, 扭矩减少总是可获得的在振动轻拍黄铜。张和Gou 做了个实验在钛合金里振动的攻丝。据研究, 摩擦扭矩被降低了并且攻丝寿命被延长了。Patil研究了对不同的处理条件的影响的研究对攻丝的扭矩和推力，在用机器制造期间和最佳条件被发现增加了攻丝寿命。 但是, 几乎没有信息可能用在高硬度钢的振动攻丝。一次系统的调查是非常必要的。本文提出在二个主要机制为在高硬度钢振动攻丝的理论分析, 即减少攻丝的扭矩和改进攻丝的扭转力强度。攻丝的实验并且被研究核实。2、 攻丝震动的理论分析 图1(a) 显示扭转力振动攻丝的过程。为了简化分析, 过程被简化对一个正交切口模型为一颗唯一切口牙依照被显示在图1(b) 。工具边缘的运动所在地在分离的振动切口的操作被显示在图1 。在各个振动周期, 金属层数被切开在牙之前在距离lc 。从点c 到d, 分离在犁耙面孔和芯片之间发生。距离在c 和d 之间由lg. 指定牙随后回来对制件, 移动从点e 到f, 与联络在牙和芯片之间被重建, 以便形成新的振动周期。搏动的切口强度和供选择运动由于振动应用是与常规过程不同的二个主要机制。 对称中心线y=0, 唯一区域y0 需要被考虑。边界条件为y=0 :当 x, z, t0, 并且时。为横向地各向同性的材料, 它证明标量(x,y,z,t) 和(x,y,z,t),这样的位移组成可以被表示:潜在的作用在波动方程:以下公式省略。3、 结论1. 在振动中攻丝使攻丝的扭转力强度提高, 并且在制件上攻丝的冲击作用延长了微震动和减少了攻丝扭矩。2. 实验结果表明当振动频率增加的时候攻丝扭矩降低和当净切口比率增加的时候攻丝扭矩增加。3. 在高硬度钢上的振动攻丝, 净切口时间比率对攻丝的扭矩有最重大的影响,当振动高度是攻丝扭矩的次要影响因素。振动频率对攻丝的扭矩有轻微的影响。4. 振动攻丝被证明是一种在高硬度钢对小孔的攻丝问题的实用解决方案。参考文献:1 Kumabe, J., 振动切口的根本性和应用, Jikkyo有限公司出版, 日本, 1979. 2 B. Zhang and F. Yang, 由振动协助的攻丝的根本方面, 材料加工技术学报.132 (2003), pp. 345352.3 D. Zhang and D. Chen, 在振动攻丝的安心面孔摩擦, 机械科学国际学报 40 (1998), pp. 12091222. 4 S.S. Patil and S.S. Pande,在振动的攻丝过程的一些调查, 机械工具和制造国际学报, 卷. 27 (1987), pp. 343350. 5 Q. Gou and D. Chen, 对在钛合金里振动攻丝小而且深螺纹的研究, 5月 (1991), pp. 301306. 6 Li. Xiangpin, Liu. Chuntu, 移动的装载和裂缝的面的三维动态重音强度因素, 卷15(1994) 95-103. 7 Xiaohua. Zhao,The stress-intensity factor for a half plane crack in a transversely isotropic solid due to impact point loading on the crack faces(翻译不通), 固体和结构国际学报, 卷 38(2001) 2851-2865. 8 Zehua. Zhou, 金属切口理论, 电子产业出版社, 中国, 1980. 特制钻头导致在合金材料中钻孔分层法的作用H. Hocheng 和C.C. Tsao摘要：由于对加入结构的需要，钻孔是次要的用机器制造的最频繁使用的操作为加强材料。分层法在钻孔阶段有着严重的问题。实践经验证明使用象锯钻子、蜡烛棍子钻子、核心钻子和步钻子如此特制钻头的好处。在本文里实验性调查在分层法起始被描述审查重要推力强度的理论预测, 然后比较这些不同的钻头的作用。结果证实分析研究结果与工程经验是一致的。超音波扫描被用来评估钻孔导致的分层法的程度。这些特制钻头的优点在数学上被说明，实验性地, 那他们的推力应力分布在钻头周围代替被集中在中心。并且允许的供给率没有导致分层法被增加。这种分析可能会导致未来创新钻头的出现。关键词：钻孔 分层法 特制钻头 超音波扫描 合金材料 1. 简介 合金材料的特殊反应在用机器制造期间实验性地广泛被观察了。择合适的切断条件的困难归结于坚硬磨蚀纤维和一个软的矩阵共存。根据实验性观察, 合金材料的一点塑料变形发生在切断期间, 并且破裂抵抗是10-100 次低于普通的钢。并且, 分层程度是很有关系的同钻孔进给能力。在钻孔的时候, 钻头的中心增加了推进的力量, 可能导致板层分离在层间连接的出口。如果钻头使用凿口的边缘可能会减小在板层边缘发生分层。蜡烛棍子钻子有一个比转弯钻子更小的中心。在一个小面积的地方钻通整个板 比较这个钻头。因而最后层碾压的宽度服从来自中心的弯曲强度。锯钻和中心钻头去除凿子, 在第二阶段这时候步钻头在它的凿子通过之后钻一个孔。本文首先提出在钻孔导致的分层法和推力强度之间使用特制钻头的实验性交互作用, 然后接下来审查预测理论模型。2. 实验分析2.1准备标本 综合碾压由被编织的WFC200 织品碳纤维prepregs 做成以堆积的序列 0/9012S 。碾压被治疗了在一台压热器在150 .C 和600 KPa 。板材被切开了成长60毫米宽24毫米， 标本做板材厚度在6 毫米。纤维容量分数是0.55, Youngs 模数是18.4 GPa, Poissons 比率是0.3 并且张力能量发行率是140 J/m2 2.2钻孔测试 钻孔测试在一个垂直的机械中心上执行了。意味在钻孔期间推力强度在钻头的出口被测量了，使用了Kistler 9273 四组分压电功率计和Kistler 5007 个充电放大器, 和存放在TEAC DR-F1 数字式记录器。放大器必须稳定工作至少一个小时。转弯钻子、锯钻子、蜡烛棍子钻子和步钻子由高速钢(直径10 毫米制成) 作成。钻子直径比率() 步钻子是0.2 。核心钻子是直径10 毫米被镀与#60 沙粒大小金刚石在前端。所有测试进行了以0.003, 0.005, 0.008, 0.0088, 0.009, 0.01, 0.011, 0.0111,0.012, 0.0122 和0.0133 mm/rev 的900 和1000 转每分钟和供给率的纺锤速度。钻孔除了在使用中核心钻子的时候其他都是无切削液的, 使用水冷以保证在钻孔期间减轻磨损。 2.3超音波扫描并获得图片 确定程度分层法生产了由各种各样的钻子, 标本由超音波C扫描技术评估钻孔导致的分层法。超音波C 扫描设备型号是AIT-5112。标本被安置在发令者和接收器之间。当发令者发出超声波, 通过接收器记录在计算机里面。 很大数量的大反差图象, 包括20000 映像点, 获得了扫描图象。各个分层法图象由灰色标度值代表(0-255) 对应于在分片密度上的区别。获得被处理的图象, 当分层法区域被设置到255 (白色) ，操练的孔的映像点设置到0 (黑色) 因为它是更小的比阈值 。适当的阈值由实验确定了列阵直方图和由原始和二进制映象核实。根据二进制映象, 计算分层法区域。分层法程度被定义作为区别在最大损伤和操练的孔(10 毫米) 53 之间 。 显示超音波C 扫描drilling 瑕疵(分层法) 从各种各样的钻头。在标本上可以看到在孔附近, 损伤是显然的从孔的边缘进入的 。注意缺陷主要发生在孔出口。以低供给率程度分层法是减小的。分层法形状在各种各样的切口情况被发现有微小区别。更高的供给率导致不仅更大的分层法, 而且分层法更加不规则的形状。3.结论 当使用特制钻头的时候钻孔导致的分层法的实验性结果被提出了。结果与重要推力强度的理论预言比较在分层法起始, 和与工业经验是一致的。由于另外钻头几何形状, 这些钻孔的钻头展示不同的水平推力随供给率变化的力。这些特制钻头好处在于在他们的更高的门限供给率在分层法起始。在五个钻头中当传统转弯钻子考虑到最低的供给率时，最高的重要供给率被蜡烛棍子钻子，随后而来的是核心钻子, 锯钻子和步钻子 。换句话说, 核心钻子、蜡烛棍子钻子、锯钻子和步钻子可能被管理以更大的供给率或在更短的周期没有分层法损伤与转弯钻子比较。他们优秀钻头设计说明他们的推力强度由钻头施加在被分布往钻头周围而不是集中在孔中心的理论模型。这种方法可能被扩大验证其它特制钻头或未来创新钻头的作用。 参考文献 1 S.R 。Ravishankar, C.R.L. Murthy, 塑造钻子在综合碾压导致的分层法, 关于非破坏性的测试的第14 个世界会议记录, 卷2, 牛津和IBH 的出版, 1996 年, 489-494页 。 2 T.L 。Wong, S.M. 吴, G.M. Croy, 在合金材料中钻孔的分层法分析, 第14 个SAMPE 技术的会议记录, 亚特兰大, GA, 美国1982 年, 471-483页 。 3 E. Persson, I. Eriksson 和L. Zackrisson, 孔用机器制造的缺陷在强度和综合疲劳寿命的作用, 综合分开A 28 (1997) (2), 141-151页 。 4 E. Capello 和V. Tagliaferri 、GFRP Drilling 损伤和残余的机械行为部份II: 静态和循环轴承装载, 综合技术研究23 (2001) (2) 学报, 131-137页 。 5 D.F 。Galloway, 在各种各样的因素对钻头表现的一些实验, ASME 79 日(1957 的) 交易的影响, 191-237 页。 6 W.R 。Russell, 为改善钻孔效率条件的钻头设计, ASTME 纸第397 日(1962), 62页 。 7 G. Caprino 和V. Tagliaferri, 在强化塑料里钻孔的损伤发现, 机械工具与 国际学报; 制造35 (1995) (6), 817-829页 。 原文1Investigation of the torque characteristics in vibration tapping of hardened steel Baolin Yinand Rongdi Han Department of Mechanical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, Peoples Republic of China Received 1 February 2005; accepted 7 July 2005. Available online 6 September 2005. Abstract Vibration tapping is presented in this paper to solve this problem, as high-speed steel tap is incapable of tapping small-hole (M3) in hardened steel (50HRC). Theoretical analysis with fracture mechanics indicates that the impact effect of the tap on the workpiece results in increased II-type stress intensity factor and extended micro cracks, leading to lower plastic deformation, reduced cutting forces and a much lower tapping torque, and the torsional rigidity of the tap is enhanced in vibration tapping as proved by dynamic analysis. The experimental results show that with well chosen amplitudes, tapping torque decreases as vibration frequency increases, and tapping torque increases as net cutting time ratio increases, where net cutting time ratio influences the tapping torque more significantly. Vibration tapping is then proved to be a practical solution to the problem of small-hole tapping in hardened steel. Keywords: Vibration tapping; Hardened steel; Micro crack; Tapping torque; Torsional rigidity 1. Introduction Small-hole tapping (M3) in hardened steel (45HRC) is a very difficult task. Hardened 0.45%C steel possesses high strength (b1700MPa) and the tapping torque (M3) in these materials is approximately 1.3Nm. Therefore, tap breakage appears to be one of the major problems in the process, possibly due to excessive torque. Hardened steel possesses high hardness, which is close to the hardness of high-speed steel (HSS) tap. It always causes machining troubles such as tool wear and tipping. High tapping torque results in other problems associated with the tapping vibration chatter including thread dimensional accuracy and thread shape error. It is clear that conventional process could not fulfill the requirement of small-hole tapping for hardened steel in view of tap strength, hardness and torsional rigidity. However, with the rapid development of modern manufacturing technologies, such as aircraft and space shuttle, some components need to be tapped after being quenched, taking geometrical accuracy and surface strength into account. Traditionally, the machining of hardened steel components is the domain of grinding operations. The technology of vibration cutting presented 50 years ago by Kumabe 1 has various effects, e.g. reducing cutting force, improving surface quality, restraining tool wear, and so on. Vibration tapping has been applied to titanium alloys and other materials to increase the tapping efficiency and reduce the overall tapping torque. There have been many contributions to vibration tapping on different materials under different process conditions 2, 3, 4 and 5. Zhang 2 built a vibration-assisted tapping device, in which a piezoelectric actuator was used to generate vibration along the axis of the tap at a frequency of 501600Hz and an amplitude of 0.15m. It turned out that a torque reduction was always obtainable in vibration tapping of brass. Zhang 3 and Gou 5 carried out the experiments on vibration tapping in titanium alloys. It was reported that the frictional torque was reduced and the tap life was prolonged. Patil 4 carried out the research on the influence of different process conditions on tapping torque and thrust during machining, and optimum conditions were found to lengthen the tap life. However, little information can be available on vibration tapping of hardened steel. A systematic investigation is therefore of great importance. This paper presents theoretical analyses on two major mechanisms for vibration tapping of hardened steel, i.e. reduction of tapping torque and enhancement of torsional rigidity of the tap. The tapping experiments were also carried out to verify the theoretical analyses. 2. Theoretical analysis of vibration tapping process Fig. 1(a) shows the torsional vibration tapping process. In order to simplify analysis, the process is simplified to an orthogonal cutting model for a single cutting tooth as shown in Fig. 1(b). The motional locus of the tool edge in the operation of separative vibration cutting is shown in Fig. 1. In each vibration cycle, a layer of metal is cut ahead of the tooth in a distance lc. From point c to d, separation between the rake face and the chip occurs. The distance between c and d is specified by lg. Subsequently the tooth comes back to the workpiece, which moves from point e to f, with the contact between the tooth and the chip being re-established, so that the new vibration cycle is formed. The pulsating cutting force and the alternate motion due to vibration application are the two major mechanisms, which are different from conventional processes. Due to the symmetry with respect to the plane y=0, only the region y0 needs be considered. The boundary conditions for y=0 are given as:(1)for x, z, t0, and(2)For a transversely isotropic material, it proves convenient to introduce scalar potential (x,y,z,t) and (x,y,z,t), so the displacement components can be represented as:(3)The potential functions meet the wave equation(4)3. Conclusions (1) The torsional rigidity of the tap is enhanced in vibration tapping, and the impact effect of the tap on the workpiece leads to extended micro cracks and reduced tapping torque.(2) Experimental results indicate that with well chosen amplitudes, tapping torque decreases as vibration frequency increases and tapping torque increases with the increase of net cutting ratio.(3) In vibration tapping of hardened steel, the net cutting time ratio has the most significant influence on the tapping torque while the vibration amplitude is the second most significant influencing factor of the tapping torque. The vibration frequency has slight influence on the tapping torque.(4) Vibration tapping is proved to be a practical solution to the problem of small-hole tapping in hardened steel.References 1 Kumabe, J., Fundamentals and application of vibration cutting, Jikkyo Publishing Co. Ltd., Japan, 1979. 2 B. Zhang and F. Yang, Fundamental aspects in vibration-assisted tapping, Journal of Materials Processing Technology. 132 (2003), pp. 345352.3 D. Zhang and D. Chen, Relief-Face friction in vibration tapping, International Journal of Mechanical sciences 40 (1998), pp. 12091222. 4 S.S. Patil and S.S. Pande, Some investigations on vibratory tapping process, International Journal of Machine Tools and Manufacture, vol. 27 (1987), pp. 343350. 5 Q. Gou and D. Chen, Research on vibratory tapping of small and deep thread in titanium alloys, 5th (1991), pp. 301306. 6 Li. Xiangpin, Liu. Chuntu, The three-dimensional dynamic stress intensity factor under the moving load on the faces of a crack. Acta mechanical solid sinica, Vol. 15(1994) 95-103. 7 Xiaohua. Zhao, The stress-intensity factor for a half plane crack in a transversely isotropic solid due to impact point loading on the crack faces. International journal of solids and structures, Vol. 38(2001) 2851-2865. 8 Zehua. Zhou, Metal cutting theory, Publishing house of electronics industry, China, 1980. Effects of special drill bits on drilling-induced delamination of composite materials H. Hocheng and C.C. TsaoAbstract：Drilling is the most frequently employed operation of secondary machining for fiber-reinforced materials owing to the need for joining structures. Delamination is among the serious concerns during drilling. Practical experience proves the advantage of using such special drills as saw drill, candle stick drill, core drill and step drill. The experimental investigation described in this paper examines the theoretical predictions of critical thrust force at the onset of delamination, and compares the effects of these different drill bits. The results confirm the analytical findings and are consistent with the industrial experience. Ultrasonic scanning is used to evaluate the extent of drilling-induced delamination. The advantage of these special drills is illustrated mathematically as well as experimentally, that their thrust force is distributed toward the drill periphery instead of being concentrated at the center. The allowable feed rate without causing delamination is also increased. The analysis can be extended to examine the effects of other future innovative drill bits. Keywords: Drilling; Delamination; Special drill; Ultrasonic C-Scan; Composite material 1. Introduction The peculiar behavior of composite materials during machining has been widely observed experimentally. A proper choice of cutting conditions is difficult due to the coexistence of hard abrasive fibers and a soft matrix. Based on the experimental observations, little plastic deformation of composite materials occurs during cutting, and the fracture resistance is 10100 times lower than that of common steels. Also, the extent of delamination is well correlated with the drilling thrust force. In drilling operations, the center of the twist drill induces a large thrust force, which can cause separation of plies at the exit as the interlaminar bonding yields. Delamination at the exit side can be reduced if a drill with a small chisel edge is used. The candle stick drill has a smaller center than a twist drill. It punches through the last pliesover a smaller area compared with the twist drill. Thus a smaller width of the last laminate is subjected to a bending force from the center. Saw drills and core drills eliminate the chisel, while the step drill cuts a hole mainly at the second stage after its chisel is through. This paper first presents the experimental correlation between the drilling-induced delamination and the thrust force in use of special drills, and secondly examines the predictions based on theoretical models. 2. Experimental setup 2.1. Specimen preparation Composite laminates were made of woven WFC200 fabric carbon fiber prepregs with the stacking sequence of 0/9012S. The laminates were cured in an autoclave at 150C and 600KPa. The plates were cut into coupon specimens of 60mm60mm. Twenty-four lamina make a plate thickness at 6mm. The fiber volume fraction was 0.55, the Youngs modulus was 18.4GPa, Poissons ratio was 0.3 and strain energy release rate was 140J/m2 . 2.2. Drilling test Drilling tests were carried out on a vertical machining center. The mean thrust forces at the exit of the drill bits during drilling were measured with a Kistler 9273 four-component piezoelectric dynamometer and Kistler 5007 charge amplifiers, and were stored on a TEAC DR-F1 digital recorder. The amplifiers have to stabilize for at least an hour. The twist drill, saw drill, candle stick drill and step drill made of high speed steel (10mm in diameter) were used. The drill diameter ratio () of step drills was 0.2. The core drills are 10mm in diameter plated with diamond of #60 grit size at the front end. All tests were run at the spindle speed of 900 and 1000rpm and feed rates of 0.003, 0.005, 0.008, 0.0088, 0.009, 0.01, 0.011, 0.0111, 0.012, 0.0122 and 0.0133mm/rev. The drilling is run dry except in use of the core drill, for which water cooling is applied to ensure that burning does not occur during drilling. 2.3. Ultrasonic C-Scan and image acquisition To determine the extent of delamination produced by various drills, the specimens were examined by the ultrasonic C-Scan technique to evaluate drilling-induced delamination. The ultrasonic C-Scan equipment was an AIT-5112 unit. The specimen was placed between the sender and receiver. When the sender emits ultrasonic waves, the attenuation through the receiver is recorded in a computer. A large number of high-contrast images, each consisting of 200200 pixels, were obtained from each scanning. Each delamination image is represented by an array of gray scale values (0255) corresponding to the differences in lamination density. To obtain the processed image, the pixel value of the drilled hole was set to 0 (black) because it is less than the threshold value, while the delamination zone was set to 255 (white). The proper threshold values were determined by examining the histogram of array values and verified by the original and binary images. Based on the binary images, the delamination area was calculated. The delamination extent is defined as the difference between the maximum damage and the drilled hole (10mm) 53. Fig. 1 shows the ultrasonic C-Scan of the drilling defects (delamination) from various drill bits. Around the hole in the specimen, the damage was evident from the edge of the hole into the test-piece. Note that the defects occur primarily at the hole exit. At low feed rate the extent of delamination is small. The shape of delamination at various cutting conditions was found to be slightly different. Higher feed rates produce not only larger delamination, but also a more irregular shape of delamination. 3. Conclusions The experimental results of the drilling-induced delamination while using special drills have been presented. The results are compared with the theoretical predictions of critical thrust force at the onset of delamination, and are consistent with the industrial experience as well. Due to the different drill geometry, these drills show different levels of the drilling thrust force which varies with the feed rate. The