激光跟踪仪动态参数自动测试系统设计

介绍了中国计量科学研究院最新研制的激光跟踪仪动态参数自动测试系统.当前,对激光跟踪仪的评价普遍局限于静态参数的评定上,而该系统却通过测量激光跟踪仪在动态条件下的各性能指标,弥补了在动态指标评定方面的缺陷,从而可以从静态、动态两个方面对激光跟踪仪进行全面的评价.     

高能激光光束质量评价参数适用性探讨

光束质量是决定高能激光系统综合性能的重要指标,针对不同应用目的,国内外研究人员提出了多种参数来评价激光的光束质量。本文对常用的光束质量评价参数在评价高能激光光束质量时存在的局限性进行了分析,重点介绍了光束传输因子BPF,对其在高能激光领域中的适用性进行了探讨,该参数的评价只需探测高能激光的功率即可,测量过程简单可行,最后对BPF测量不确定来源进行了定性分析。     

关节式坐标测量机激光测量头参数标定

在三维视觉测量中,标定方法对测量结果的影响是决定性的.本文通过分析、比较各种视觉模型及标定方法,采用考虑镜头畸变因素的三维视觉模型以满足高精度测量系统的需求.由于关节式坐标测量机的激光测量头,使用单摄像机和线结构光来匹配被测物体表面的三维数据,本文设计了一种新型的阶梯形标定块,通过标定块图像和激光条纹图像完成了摄像机的内外参数标定和激光平面参数标定.实验证明,该标定操作过程简单,易于实现自动化,且具有较高的标定精度.     

激光参数对碳纤维复合材料质量烧蚀率的影响

为了研究激光参数对碳纤维增强有机硅改性环氧树脂复合材料质量烧蚀率的影响规律, 选用不同激光参数、采用高强度CO₂激光器对该复合材料进行了激光辐照试验。分别分析了入射激光的辐照时间、强度和光斑直径对碳纤维增强有机硅改性环氧树脂复合材料质量烧蚀率的影响规律。研究结果表明: 激光辐照时间对该复合材料的质量烧蚀率的影响不大, 而该复合材料的质量烧蚀率随入射激光强度和光斑直径的增大而增大。      

激光透射连接PET的工艺参数建模与优化

为了获得激光透射连接聚对苯二甲酸乙二酯薄板的最佳工艺参数,采用响应曲面法对影响激光透射连接质量的四个主要影响因素即激光功率、扫描速度、压紧力、扫描次数进行建模与优化。利用Design Expert软件分析了主要工艺参数对连接质量的影响,并获得了最佳工艺参数:激光功率33.2W、扫描速度9 mm/s、压紧力0.45 MPa、扫描次数3。最后,把响应曲面所建立数学模型的预测结果与试验的实际结果进行对比,发现两者吻合良好。     

基于线结构激光的滚柱表面参数测量系统

为实现行星滚柱丝杠的滚柱表面参数测量,建立基于线结构激光的测量系统,针对滚柱螺纹牙型角、螺距和牙型高等表面参数的测量方法进行研究。首先,根据线激光三角法的测量原理,设计搭建测量装置系统。激光经成像系统,通过CCD摄像头获取到线激光条纹图像,对其进行预处理并提取出激光条纹中心。其次,根据螺纹形状特点对获取的螺纹轮廓进行ROI提取,将轮廓线分段进行处理,简化处理难度并获取不同的表面信息参数。最后,根据提取出的分段利用曲线拟合、特征点提取等方法计算所有滚柱表面参数。经实验验证:该文提出的测量系统对牙型角的测量重复性达到0.6°,螺距测量的重复性达到15μm,牙型高测量的重复性达到8μm,基本达到滚柱表面参数测量的要求。     

TC4零件激光快速修复加工参数带的选择

通过研究激光加工参数,包括激光功率、光束扫描速度以及送粉率对热输入效率η和熔覆层形状系数ζ的影响规律,并结合激光快速修复过程对热输入效率和熔覆层形状系数的要求,建立了TC4激光快速修复的加工参数带。采用文章所确定的加工参数带中的参数,有利于减小激光快速修复件的变形,得到的修复件无熔合不良缺陷。     

激光焊接参数对钛合金薄板组织及力学性能影响

目的 研究不同激光焊接工艺参数对1 mm厚TA18薄板焊接的影响,为有效解决焊缝缺陷、脆性相等问题提供参考.方法 采用大功率碟片激光器,在氩气环境下,对1 mm厚TA18薄板进行激光焊接实验,对不同激光焊接参数下的焊接接头进行微观组织观察及力学性能测试.结果 当激光焊接功率为1.5 kW时,焊缝呈"葫芦"状,熔宽大且不...     

激光工艺参数对熔覆层稀释率的影响

研究了自动送粉激光覆工艺参数对熔覆层稀释率的影响规律。结果表明,粉末流量大小是块定激光熔覆层稀释率的最主要因素,它通过产生“热屏蔽”效应得影响稀释率,激光功率,扫描速度也对稀释率有较大的影响。     

脉冲激光参数在烧蚀固体材料过程中的影响

介绍长脉冲激光和短脉冲激光与固体材料相互作用时的物理模型。介绍激光作用过程中,脉宽、波长等激光参数对材料烧蚀阈值以及加工质量的影响。     

Microwave-Frequency Modulation of the Gasdynamic Parameters of Plasma by Laser Radiation

Numerical and asymptotic calculations are performed of the gasdynamic parameters of laser-induced plasma under the effect of high-power laser radiation with microwave-frequency modulation of its intensity. The results of these calculations are compared for the amplitudes of oscillation of these parameters. It is demonstrated that the values of the parameters may be found using the averaging method and represented in the form of the sum of two parts, of which one part is the solution in the absence of modulation, and the other part describes small-scale oscillations about this solution.     

Direct Slicing Based on Material Performance and Process Parameters for Selective Laser Sintering

Direct slicing from GAD models to generate sectional contours of the part to be sintered for Selective Laser Sintering （SLS） may overcome inherent disadvantages of using a Stereo Lithography （STL） format. In this paper, a direct slicing procedure is proposed for Selective Laser Sintering based on material performance and process parameters. Slicing thickness depends on the 3 D geometric model, material performance and process parameters. The relationship among material performance, process parameters and the largest slicing thickness is established using analysis of a sintering temperature field. A dynamic linked library is developed to realize direct slicing from a CAD model.     

激光多层熔覆纳米陶瓷层工艺参数优化

为了深入了解激光多层熔覆工艺与涂层性能之间的关系,采用压片预置式激光多层熔覆工艺制备了纳米Al2O3-13%TiO2(质量分数)陶瓷层;通过3因素3水平正交试验分析了激光熔覆熔池闭环控制温度、超声振动频率及保温箱预热温度对涂层结合强度的影响,并对激光熔覆工艺参数进行了优化;通过扫描电镜(SEM)和结合强度测试研究了最优工艺下所得涂层的形貌和性能。结果表明:影响涂层结合强度的因素主次顺序依次为熔池闭环控制温度、保温箱预热温度、超声振动频率;激光多层熔覆纳米Al2O3-13%TiO2涂层最佳工艺参数为熔池闭环控制温度2 500℃,超声振动频率50 kHz,保温箱预热温度400℃;优化工艺熔覆的涂层各层之间无明显界面,涂层内部致密、连续,基本无孔隙及贯穿性大裂纹,涂层结合强度明显提高,达66.3 MPa。     

基于灰色关联分析激光熔覆Ni60A工艺参数优化

目的 针对激光熔覆Ni60A成形效率问题,研究工艺参数对单道熔覆效率和高宽比的影响规律,实现熔覆层工艺参数的预测与优化.方法 基于正交试验设计方法,采用信噪比对试验结果进行转换,并通过灰色关联分析多目标优化方法进行工艺参数优化.结果 最优工艺参数:激光功率为1900 W,扫描速度为8 mm/s,气流量为16 L/min...     

Angle Encoding Disk Surface Parameters Evaluation Using Conventional Laser Head: Initial Study

Surface quality is one of the most important parameters in mechanical treatment. In recent years a great number of contact and non-contact surface quality measurement methods have been created. This article covers a non-contact laser method of surface parameter evaluation, intended for the evaluation of the surface quality of an angle encoder disk. For such a measurement, this paper proposes using a conventional compact disc laser-reading unit. The proposed system is relatively simple and inexpensive. The device allows measuring unevenness in the surface thickness of an encoder disk, as well as its surface roughness and profile details. The structure of the measurement system, the static and dynamic calibration results and the experimental surface measurement results for an angle encoder disc are presented.     

Process Parameters Optimization of Laser Beam Welded Joints by Neural Network

Laser beam welding of C-Mn steel plates with Ni powder filler metal has been performed. Metallography samples of the welded cross-section have been observed by scanning electron microscopy (SEM) and submitted to energy dispersive spectroscopy to obtain Ni concentration profiles. On the basis of the experimental results, neural networks have been carried out. These networks were first validated and then utilized to foresee Ni concentration along the welded thickness. The objective of obtaining the best Ni penetration and minimizing powder loss was reached optimizing, by numerical simulation, process parameters, such as powder rate and joint geometry.     

Dependence of Endohedral Fullerenes Formation on Laser Ablation Parameters of Carbonaceous Materials

Endohedral fullerenes containing yttrium atoms were produced by laser irradiation of mixtures of carbonaceous compounds and yttrium oxide targets. The laser irradiance, the temperature, the ablation wavelength and the nature of the target were studied more precisely. The analyses are performed with a Laser Microprobe coupled with Mass Spectrometry (LMMS). The study of spectral fingerprints on both positive and negative modes allows to evaluate the relative distribution of metalfofullerenes compared to classical fullerenes according the laser ablation parameters.     

接装纸材质和激光打孔参数对卷烟的影响研究

目的 研究不同材质接装纸和激光打孔参数对在线激光打孔卷烟的影响。方法 应用扫描电镜检测卷烟样品的打孔微观结构,包括纸的表面形貌、打孔的大小、孔间距等指标,对相应接装纸的卷烟物理指标差异和烟气指标差异以及相关性进行研究。结果 激光打孔脉冲时间、打孔数量对激光打孔的微观形态有较大影响,打孔脉冲时间和打孔数量与卷烟烟支吸阻呈线性负相关,与总通风率呈线性正相关。在相同激光打孔参数下,不同接装纸材质纸张孔径和孔间距明显不同,单孔的形态差异较大;不同材质接装纸对卷烟物理指标影响较小,对卷烟烟气指标有一定影响。单孔打孔的高质量有利于提高卷烟物理指标和烟气指标的稳定。结论 不同材质接装纸的在线激光打孔应用效果不同,可以根据烟支设计需要进行选择接装纸材质。