【作者】 崔永鹏；

【导师】 韩荣第；

【作者基本信息】 哈尔滨工业大学 ， 机械制造及其自动化， 2006， 硕士

【摘要】 与传统的攻丝方式相比,振动攻丝是一种较新的复合加工方法,它可以提高工艺系统刚度,有效地降低攻丝扭矩,提高螺纹加工质量,特别是可以解决钛合金、高温合金等难加工材料小孔攻丝的难题。故研究难加工材料的振动攻丝具有重要的现实意义。首先,对丝锥进行运动学分析表明:振动攻丝可以提高丝锥的等效扭转刚度,振动攻丝的重复切削特性可以降低摩擦扭矩;通过弹性力学及断裂力学分析表明:脉冲力切削使应力强度因子发生剧烈变化,微裂纹的产生与扩展导致攻丝扭矩的降低;振动攻丝的脉冲切削,有利于切削液进入切削区,降低摩擦扭矩。然后,采用原振动攻丝机对高温合金GH4169和钛合金TC4两种难加工材料进行了攻丝试验。单因素法试验以振动频率f、振幅A及净切削时间比nc为参数,研究各个参数对振动攻丝扭矩的影响规律;正交设计试验法是根据正交表进行试验,进而采用回归方程求解振动攻丝扭矩的经验公式。并且采用不同切削液进行了振动攻丝试验,研究了切削液的效果。最后,针对原攻丝机控制系统的不足,对控制系统的硬件部分、PCB板及控制面板进行了设计,并用模块化思想编写了程序。振动攻丝的试验结果表明:在试验条件下,攻丝扭矩随频率的提高而降低,随净切削时间比的增加而增大,且净切削时间比对攻丝扭矩的影响均为最显著,振幅对攻丝扭矩的影响呈非线性;振动攻丝所得的螺纹的牙形完整,形状规则;切削液的使用可以降低振动攻丝扭矩。故振动攻丝可以有效地解决难加工材料小孔攻丝的工艺难题。更多还原

【Abstract】 Compared with the traditional method of tapping, vibration tapping is a new method of compound manufacturing. It has the advantages of enhancing the torsional rigidity of manufacture system, a much lower tapping torque, much better quality of screw thread. Vibration tapping is then proved to be a practical solution to the problem of small-hole tapping in difficult-to-cut materials. Now researching on the mechanism of vibration tapping and designing a much better system has a great practical significance.Through analyses of moving, the vibration tapping can enhance the torsional rigidity of manufacture system, and having a much lower friction torque. Through analyses of elasticity and plastic, it proofs that the impulse cutting can crack the metal, the crack will result in fall of tapping torque. The impulse cutting also let the lube be easy to get in the section of cutting, it help to low the friction torque.By using simple-factor experiment and Orthogonal Experiment the author have done a great deal experiment with GH4169 and TC4. In simple-factor experiment, the author used amplitudes, frequency, net cutting time ratio as the parameters, to get the regular pattern of tapping torque as parameter changing. Through Orthogonal Experiment, the author have gained the experience formula. By using different lube to do experiment, the author research on the effect of lube.Lastly, contra-posing with the disadvantage of former system, designed a new system and finished the control program by using the idea of modularization.Through the experiment of vibration tapping, we find the tapping torque augmenting as the frequency diminishing, augmenting as net cutting time ratio augmenting, and it is most influenced by net cutting time ratio. Use of lube is effective to low friction torque. Morphology of teeth of vibration tapping is integrated. All these proof that vibration tapping is a effective method to resolve small hole tapping in difficult-to-cut materials.更多还原