共查询到17条相似文献,搜索用时 78 毫秒
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激光制孔是一种非接触式、无工具损耗的先进加工技术,现阶段已经在航空、航天和船舶等领域广泛应用;但激光制孔后会出现热影响区、再铸层和熔渣等质量缺陷以及锥度等形貌缺陷,极大地影响了孔的后续应用,因此,在激光制孔过程中增加额外的辅助手段以提升其质量是十分必要的.首先,从时间尺度上分析了激光与靶材的作用机理,阐述了激光加工时的物理现象,明确了提升制孔质量的切入点.针对国内外在激光制孔过程中应用的辅助手段进行了系统的综述,详细分析了介质辅助、焦点位移辅助和在线监测辅助对孔形孔性的提升机制,并探讨了激光制孔技术未来的发展方向. 相似文献
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激光制孔是一种非接触式、无工具损耗的先进加工技术,现阶段已经在航空、航天和船舶等领域广泛应用;但激光制孔后会出现热影响区、再铸层和熔渣等质量缺陷以及锥度等形貌缺陷,极大地影响了孔的后续应用,因此,在激光制孔过程中增加额外的辅助手段以提升其质量是十分必要的.首先,从时间尺度上分析了激光与靶材的作用机理,阐述了激光加工时的物理现象,明确了提升制孔质量的切入点.针对国内外在激光制孔过程中应用的辅助手段进行了系统的综述,详细分析了介质辅助、焦点位移辅助和在线监测辅助对孔形孔性的提升机制,并探讨了激光制孔技术未来的发展方向. 相似文献
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激光制孔是一种非接触式、无工具损耗的先进加工技术,现阶段已经在航空、航天和船舶等领域广泛应用;但激光制孔后会出现热影响区、再铸层和熔渣等质量缺陷以及锥度等形貌缺陷,极大地影响了孔的后续应用,因此,在激光制孔过程中增加额外的辅助手段以提升其质量是十分必要的.首先,从时间尺度上分析了激光与靶材的作用机理,阐述了激光加工时的物理现象,明确了提升制孔质量的切入点.针对国内外在激光制孔过程中应用的辅助手段进行了系统的综述,详细分析了介质辅助、焦点位移辅助和在线监测辅助对孔形孔性的提升机制,并探讨了激光制孔技术未来的发展方向. 相似文献
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叶伟昌 《机械工人(冷加工)》1991,(9):14-19
铰孔是普遍应用的一种精加工和半精加工孔的方法,加工孔径在φ1~φ100mm之间,尺寸精度一般可达H8~H7级,手铰时可达H6级,表面粗糙度Ra1.6~0.2。铰孔用的刀具,目前生产上仍以标准的多齿铰刀为主,见图1。它是由工作部分、颈部和柄部三部分 相似文献
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《机械制造与自动化》2016,(3):42-46
通过对制孔轴向力、扭矩、表面质量以及孔径尺寸等制孔质量评价指标的测量,研究了加工参数(主轴转速、每齿进给量)对CFRP/Al叠层材料的制孔质量的影响规律。结果表明,提高转速与减少每转进给量可以降低CFRP的钻削轴向力与扭矩;减少每转进给量是提高CFRP孔壁质量的最有效的途径,但同时也会提高CFRP入口撕裂风险。使用高转速钻削时会降低Al板出口毛刺、避免CFRP材料缩孔现象;但是使用高转速钻削时同样会带来CFRP材料出口毛刺增加的问题。 相似文献
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现代飞机制造业中钛合金使用日益广泛,而螺旋铣孔是飞机制造装配中大孔径连接孔加工的一种新工艺方法。对于钛合金的大孔加工,螺旋铣孔制孔质量显著高于钻孔。实验研究了每齿轴向进给量、每齿切向进给量、切削速度与偏距四个参数对于钛合金螺旋铣孔质量的影响。实验结果表明:每齿轴向进给量与切削速度是出口毛刺高度的主要影响因素;孔径偏差的主要影响因素是每齿切向进给量与每齿轴向进给量;每齿切向进给量与每齿轴向进给量的增加会导致切削表面残余高度增加,从而造成螺旋铣孔孔壁表面粗糙度随着而上升;偏距增加会保证足够的排屑空间,从而避免孔壁划伤,对于提高孔壁质量有利。通过优化选择工艺参数,可以满足飞机制孔工艺质量的要求。 相似文献
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Chao-Ching Ho Guan-Ru Tseng Yuan-Jen Chang Jin-Chen Hsu Chia-Lung Kuo 《The International Journal of Advanced Manufacturing Technology》2014,73(1-4):329-340
This study explored the feasibility of magnetic-field-assisted laser percussion drilling on highly reflective materials, i.e., Al5052. During laser percussion drilling, the Lorentz force generated by the assisting magnetic field affects the laser-induced plasma. A magnetic field simulation was performed to investigate the field strength of the circular hollow permanent magnet used herein. The influence of the magnetic field and laser radiation energy on the penetration depth and inlet diameter was examined. All experiments were performed in air without additional process gas. It was found that at laser radiation energy of 200 mJ with magnetic field assistance, the penetration depth could be increased by 87.7 % and the inlet diameter could be reduced by 23.7 % as compared with percussion drilling without the applied magnetic field. However, when the laser radiation energy was reduced to 120 mJ, the magnetic field confined the plasma plume; therefore, the penetration depth decreased. 相似文献
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Aristidis Stournaras Konstantinos Salonitis George Chryssolouris 《The International Journal of Advanced Manufacturing Technology》2010,46(5-8):589-603
In percussion laser drilling, a sufficiently powerful laser beam is used for the formation of a hole on the workpiece. In this study, the investigation of utilizing optical signals, acquired by means of photodiodes and emitted from the processing zone for real-time monitoring, is presented. The correlation between the sensor output and the geometry of the hole, determined by the depth and upper diameter, is investigated, and the results are presented. In general, the results indicate that there is a strong correlation between the optical signal output and the diameter of the hole. 相似文献
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《Measurement》2016
This paper presents a novel method for controlling the laser-drilling process for a hole by monitoring induced plasma emission. The variation of light brightness from laser-induced plasma is used as an indicator to control laser percussion drilling. Through on-line plasma emission acquisition and analysis, we obtain the positive association between the increased depth and the optical signal output. A coaxial photodiode is used to estimate the brightness levels of laser-induced plasma. The above constitute an inexpensive and practical on-line feedback system that can be easily implemented in the laser systems. All of the processing work is performed in air under standard atmospheric conditions without gas assist. The acquired signal for drilling could also be used as an input to a focus point process control scheme. Moreover, the technology demonstrates the feasibility to develop an automated laser micromachining system. Experimental results show that drilling efficiency was increased 47% by applying the proposed defocusing laser percussion drilling. 相似文献
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Aristidis Stournaras George Chryssolouris 《The International Journal of Advanced Manufacturing Technology》2010,46(5-8):611-620
Laser drilling is a well established sheet metal processing method. The development of a monitoring system capable of assessing the dimensions of holes is the subject of this work. This paper investigates the applicability of an acoustic-based monitoring system for the percussion laser drilling process. Correlation between the sensor output and the hole's geometry, determined by its depth and upper diameter, is investigated and the results are presented. In general, the results indicate that a correlation exists between the acoustic signal output and the depth of the hole. 相似文献
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Jens Holtkamp Andreas Roesner Arnold Gillner 《The International Journal of Advanced Manufacturing Technology》2010,46(9-12):923-930
This paper presents vibration reduction control of a voice coil motor (VCM)-driven actuator for SPM applications. We had developed a VCM nanoscanner. The scanner has flexure hinges structure. However, the VCM nanoscanner has some problems of thermal drift and small damping compared to the PZT driven nanoscanner. Especially, the small damping coefficient of the VCM nanoscanner causes mechanical vibration when the control input signal is near to the resonance frequencies of the scanner. Additionally, disturbance to the VCM scanner and electronic noise in the sensor also causes the mechanical vibration when they are near to the resonant frequencies. The mechanical vibration reduces the servo bandwidth as well as the accuracy, which deteriorates the AFM image of the samples. We design input shaping prefilter to reduce the signal applied to the VCM nanoscanner and electronic noise in the sensor whose frequency is close to the resonant frequency of the VCM nanoscanner. We measure the time and frequency response of the VCM scanner without using the prefilter and with using the prefilter. Finally, the topology images of a bare wafer are measured and compared using the AFM. 相似文献
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This study investigates the effect of six parameters in the repeatability of drilled holes in laser percussion drilling process
by means of statistical techniques. Peak power, pulse width, pulse frequency, number of pulses, gas pressure and focal plane
position were considered as independent process parameters. Experiments were designed with the aim of reducing the number
of required experiments. The response surface method was used to develop the models for required responses. The significant
factors in the process were selected based on the analysis of the variance (ANOVA). The experiments were conducted in mild
steel sheet with a thickness of 2 mm. Each experiment was repeated 35 times in order to investigate the repeatability of the
process. The equivalent entrance diameter, percentage of standard deviation of entrance diameter (%STD Eq Dia), circularity
(ratio of minimum to maximum Feret’s diameter) and its standard deviation (STD circularity) were selected as process characteristics.
The %STD Eq Dia and STD circularity, respectively, show the repeatability of equivalent diameter and circularity in the process.
The results show that the process of drilling smaller hole diameters is more repeatable than drilling larger holes. Pulse
width, gas pressure, focal plane position, peak power and number of pulses, respectively, have significant effect on the repeatability
of hole diameter and circularity. Pulse frequency has no significant effect on the repeatability of the process. 相似文献