高性能数控激光切割机设计要点

介绍了激光切割工艺的优点及数控激光切割机的基本构成。在此基础上，重点论述了数控激光切割机主机的构成部件及设计要点。     

The significance of deposition point standoff variations in multiple-layer coaxial laser cladding (coaxial cladding standoff effects)

Direct laser deposition (DLD) is an additive manufacturing process that builds up a part layer-by-layer by fusing metal powder to a solid substrate. A coaxial laser and powder delivery head is commonly used, and here a critical process variable is the standoff distance between the nozzle and the material deposition point. This contribution investigates the role of this variable and the effect that it has on the final part geometry. The experimental results show that good layer consistency can, in fact, be obtained with no movement of the substrate between layers for more than 20 layers, or 10 mm under tested conditions, and that poorer results are obtained by regular movement of the substrate by a badly chosen constant amount. A theoretical analysis of the situation establishes a method to estimate melt pool size using an analytically calculated temperature near the heat source. Based on this, simple heat and mass flow models are established to allow some of the results to be explained.     

Microstructure and tribological properties of Cuss-toughened Cr–Cu–Si metal silicide alloys

Wear resistant Cr–Cu–Si metal silicide alloys with different Cu contents were fabricated by the laser melting process. The Cr–Cu–Si alloys have a similar microstructure consisting of the Cr₅Si₃/CrSi dual-phase primary dendrites and the interdendritic Cu-based solid solution (Cu_ss). The Cu content has no effect on the phase constitutions of the alloys. The Cr₅Si₃/CrSi dendrite volume fraction and hardness of the Cr–Cu–Si alloys decrease with the increasing Cu content. Wear test results indicate that all the Cu_ss-toughened metal silicide alloys have excellent wear resistance and low coefficient of friction. Wear resistance increases and friction coefficient decreases with the decreasing Cu content.     

Calibration system based on a laser interferometer for kinematic accuracy assessment on machine tools

This paper deals with a method for the dynamic calibration of the kinematic accuracy of lathes and thread grinding machines in screw-cutting mode but free of load. It utilizes a precision polygon mounted on the spindle, in conjunction with a trigger device to generate angular pulses. A laser interferometer system assesses the longitudinal position of the saddle with respect to a cube-corner affixed on the chuck. As the spindle rotates, a string of pulses is generated by the angular trigger device. These pulses are used for triggering the laser interferometer. A software package has been elaborated to enable on-the-fly data acquisition and to display the kinematic errors in graphical form. The components of the kinematic error considered are the progressive pitch error, the cyclic error and spindle-free float. Application of this kinematic error calibrator on a universal and a CNC lathe has been carried out. Test results are presented and commented.     

Autogenous welding of Hastelloy X to Mar-M 247 by laser

Mar-M 247, a nickel-base cast alloy, is used widely in aeroengines for parts such as blades, vanes and airfoil. Hastelloy X is one of the most oxidation- and corrosion-resistant nickel-base wrought alloys. In order to join such alloys in aeroengine manufacturing, laser beam welding has been carried out with lap and butt joints using a 1.2 and a 6.0 kW CO₂ laser. Cracks in the fusion zone can be eliminated by deliberate misalignments in the ranging of the laser beam by 0.2−0.3 mm onto Hastelloy X. Correlations between cracking behavior, hardness of the beads and misalignments have been investigated. Metallurgical analysis using electron microscopes has revealed the redistribution of alloy elements, the microstructures of the fusion zone and microfissures in the heat-affected zone (HAZ).     

激光切割加工中CAPP系统的设计与研究

介绍了一种激光切割加工中CAPP系统工艺数据库设计与开发，该系统可以提供激光切割加工的各种加工方法和工艺参数的选择，实现激光切割工艺标准化，并为智能化工艺设计提供了基础。     

声光调Q Nd:YAG脉冲激光修锐树脂结合剂CBN砂轮

采用声光调Q Nd:YAG脉冲激光径向辐照，对树脂结合剂CBN砂轮进行修锐试验研究。研究了单脉冲激光辐照下，平均功率，脉冲频率和离焦量等参数对烧蚀凹坑深度的影响，由此可方便获得合适的激光修锐参数；分析了声光调Q YAG脉冲激光修锐树脂CBN砂轮的选择性去除机理，观察并比较了声光调Q脉冲激光，连续激光和机械法修锐后砂轮表面的地形地貌，试验表明声光调Q Nd:YAG脉冲激光径向辐照修锐树脂CBN砂轮，可获得更为良好的修锐效果。     

Laser Cladding of an Al-11.7Wt%Si Alloy on ZM5 Magnesium Alloy to Enhance the Corrosion Resistance

MG and its alloys are widely used in aerospace andautomotive in industry.Its poor corrosion resistancerestricts application of Mg alloy.Laser cladding andlaser surface melting are advantageous processes forimprovement of the corrosion resistance of themagnesium alloy[1-2].In the present study,lasercladding of an Al-11.7Wt%Si alloy with two differentthickness on ZM5die cast alloy was performed withCC>2laser with different powder thickness.1.Experimental ProcedureDie cast plates of ZM5Mg a…     

薄壁方管激光弯曲过程的模拟研究

薄壁方管激光弯曲是一种利用激光加热来实现构件的柔性成形技术。研究了薄壁方管激光弯曲有限元模拟中的型处理、单元技术、边界条件、动热源构建、材料热吸收系数的选择、边界条件与初始条件等关键技术的处理，实现了薄壁方管激光弯曲过程的有限元模拟，分析了其变形机理。     

航空材料的两种激光表面处理技术

针对航空材料的表面强化问题,分析了激光表面处理技术在航空材料上应用的发展现状.论述了两种类型激光表面处理技术的基本原理和国内外研究现状.分析了激光表面处理技术在航空材料上应用的发展方向.