With respect to transformable 9Cr oxide dispersion strengthened (ODS) steels, the interaction between moving phase interface and oxide nanoparticles could lead to the inhomogeneous distribution of oxide particles. Nevertheless, the coupled effects between oxides and phase interface upon dynamic recrystallization still remains unclear. In this work, transformable 9Cr ODS alloys with different Ti and C additions were fabricated, hot-rolled with different reductions and then annealed. For each ODS alloy, dynamic recrystallization of austenite occurs upon hot-rolling, and the oxides in hot-rolled alloys are distributed in lines parallel to rolling direction. With the hot rolling reduction increasing, the line spacing of oxides is decreased, and alloy composition has negligible effects on oxide distribution compared to rolling reduction. A strong <110> fiber texture is dominated in each hot-rolled alloy, and with the deformation reduction increasing, the grain morphology changes from equiaxial to elongated ones. Both alloying composition and rolling reduction have significant effects on the mechanical performance of ODS alloys at room temperature and 650 °C. By optimizing the hot rolling and annealing treatment processes, the 9Cr ODS alloy with both Ti and C additions exhibits favorable strength and ductility at both room temperature and 650 °C.

Aiming at the problem of insufficient rigidity of the tool system and unbalanced radial force during deep hole machining, this paper designs a deep hole connector using the fluid dynamic pressure lubrication principle. The deep hole connector includes double-bridge strain gauges and tiltable tiles, which can increase the rigidity of the tool system by using the oil film support stiffness and offset the unbalanced radial force of synchronous detection by adjusting the oil film pressure in real time. First, the mathematical model of tiltable tile is established, the oil film thickness formula is derived, and the formula of oil film pressure is derived. Then, based on Fluent software, the fluid simulation of the deep hole connector is carried out. The simulation adopts a single-factor experiment method, and the change law of oil film pressure on tiltable tile is analyzed under different conditions, respectively. The results show that during deep hole machining, the oil film pressure can be adjusted by adjusting the parameters of workpiece speed, cutting fluid viscosity, tile tilt angle, and tile wrap angle, and then achieve the purpose of increasing the rigidity of the tool system and offsetting the unbalanced radial force.

The generating conditions and affecting elements of oil film pressure of deep hole drilling are investigated based on the idea of hydrodynamic lubrication. A new kind of BTA deep hole drilling connector with tilting pads was created based on meeting the cutting parameters and structure requirements. The connector may change the tilting pad angle by adjusting the voltage of the piezoelectric ceramic stack, allowing for real-time control of the oil film pressure, counteracting the radial force generated by the tool during the cutting operation, and reducing roundness error. The range of oil film pressure was determined theoretically to be 0-9.809 N, and a link between the tilting angle and the stack voltage was found. 24 sets of comparative experiments were conducted, using the Phi 37.8 x 500mm, Phi 38.3 x 500mm, and Phi 38.8 x 500mm deep hole as an example, to confirm the impact of connector presence or absence on the deep hole processing. The findings demonstrated that when the wedge gap is 0.45 mm, the latter radial force was decreased by 3.20 %similar to 47.50 % while maintaining the same drilling circumstances. After 120 sets of cross-sections of a split deep hole specimen were found using a roundness tester, it was discovered that the roundness error of the latter had decreased by 27.98 %-49.73 %.

Objective The circular structured light based measurement system can generate circular structured light by reflecting a laser beam through a conical reflector,and utilizing laser triangulation and close-view photogrammetry algorithms to calculate three-dimensional coordinates.This kind of measurement system has been widely studied by researchers due to its advantages such as high flexibility,high accuracy and simple structure.The current circular structured light system has certain problems in measuring roundness.It is difficult for the laser,the camera and the deep hole to be measured to be parallel or coaxial,which leads to the inability to measure the accurate circular cross-section.A measurement system based on circular structured light is constructed,the mechanism of systematic error is analyzed and a method based on the circular structured light system to measure circularity is proposed,which provides some compensation for systematic errors. Methods The mechanism that generates systematic errors in the measurement of roundness by the circular structured light system is analyzed(Fig.3).A high-precision electric linear slide is used to move the deep hole parts to be measured to complete the full-field measurement,and a high-resolution point cloud is obtained and fit the axis.Through the Rodrigues formula,the inner surface point cloud rigid body will be transformed to the point cloud axis and z-axis parallel to the location of the point cloud axis,searching for the z coordinate near the point as a cross-section of the roundness of the assessment point(Fig.4).The roundness evaluation is completed by the grid search algorithm(Fig.5). Results and Discussions The compensation by the proposed method works well in roundness measurement experiments,in which the measurement uncertainty is 4.78 μm(Tab.3).For the circular structured light measurement system,a long rod can be assembled after the laser to increase the axial measurement range of the system.For the proposed circular structured light roundness measurement method,the resolution of the 3D point cloud can be improved by reducing the step length of the motorized linear slide to further improve the measurement accuracy. Conclusions A three-dimensional measurement system of circular structured light is built,the error generated when the circular structured light system measures roundness is analyzed,and a method based on the circular structured light system to accurately measure roundness is proposed.It is verified that the use of the method to measure roundness has a good compensating effect through the measurement experiments.

As one crucial processing parameter in selective electron beam melting (EBM), electron beam current has a significant effect on the cooling rate and heat accumulation in EBM. In this study, the local microstructure and mechanical performance of Ti-6Al-4V alloys fabricated by EBM with different electron beam current are examined. The results indicate that the microstructure of EBM-manufactured Ti-6Al-4V alloy consists of alpha+(3 dual-phase structure. There is an obvious difference in the amount and morphologies of (3 phases in bottom and top regions of as-fabricated Ti-6Al-4V alloy. With the electron beam current increasing, the amount of (3 phases in bottom regions gradually decreases. The granular or short rod-like (3 phases is dominated in the bottom region, while (3 plates are prevalent in top regions. With the building height increasing, the alpha variant selection is enhanced, and the alpha variant selection at top regions is stronger at higher electron beam current. Smaller electron beam current is beneficial to obtain EBM Ti-6Al-4V alloy with uniform microstructure and mechanical property, and both of bottom and top regions of EBM Ti-6Al-4V alloy at 17 mA exhibit comparable mechanical performance to those values in previous studies.

The flow stress and microstructure evolution of 9Cr oxide dispersion strengthened (ODS) steels were investigated by isothermal compression at 1000–1150 oC with strain rates from 0.001 to 1 s− 1. Microstructure characteristics of ODS steels under various condition were studied using the EBSD and TEM techniques. At each deformation temperature, PortevinLe–Chatelier (PLC) effect characteristics of repeated serrated stress was observed, as the strain rates were 0.01, 0.1 and 1 s− 1. The serrations fluctuated about the mean flow curve in quick succession, and the critical strain for the PLC effect was related to both the deformation temperature and strain rates. The stress drops at strain rates of 0.01 and 0.1 s− 1 were smaller than those at 1 s− 1. The strain rate affected the dynamic recovery and recrystallization of austenite grains, as well as the texture components of martensite transformed from austenite. Cap-shaped oxide particles in as-fabricated and hot deformed steels were characterized in detail. The cap parts of cap-shaped oxide particles were depleted of alloying elements, and the caps were crystal or amorphous. Large-sized oxide particles were easier to be deformed than small-sized ones. Despite of the oxide deformation, the PLC effect was still suggested to be related to the solute-dislocation interaction.

针对4-URU型柔性并联机构,提出了一种对支链刚度的新型求解方法,应用软件仿真结果验证该方法的有效性.首先,利用螺旋理论对4-URU刚性并联机构进行自由度分析,采用柔性铰链替换法设计相应的柔性并联机构.基于柔性铰链刚度矩阵,利用转换矩阵法求得支链的铰链刚度矩阵,利用有限元理论分别求得支链各柔性杆刚度,通过线性叠加求得支链的总刚度矩阵,最后利用MATLAB进行理论计算,得到支链在X、Y、Z方向产生的变形量.并用ANSYS软件对模型进行仿真分析,结果表明,理论计算与仿真结果基本一致.验证了该方法求解支链刚度的有效性,为利用该方法求解整个柔性并联机构的刚度提供理论依据,为研究柔性并联定位平台的精度提供了帮助.

针对并联机床摆角小,难以加工复杂曲面零件的缺点,提出一种新型(2PSR+PUU)&RP混联机床的机构构型.首先运用螺旋理论以及修正的K-G公式对机构自由度进行分析计算与验证.运用闭环矢量法对机构进行运动学分析,给出该机构的位置逆解以及基于粒子群算法的正解,确定驱动块和动平台的位姿关系.在SolidWorks软件中采用动静结合法绘制出其工作空间,并利用ADAMS对其摆角进行测算,验证了机构模型的正确性以及机构运动的可实现性.研究表明,混联机床具有3T2R这5个自由度,有较大的工作空间,且其刀具摆角可达(0°～90°),通过刀具的大摆角转动和五轴联动可应用于部分汽轮机,水轮机和航空发动机的叶片和复杂曲面零件的加工.

针对微电子领域高温共烧陶瓷(HTCC)产品的批量化生产,依托中国电子科技集团公司第二研究所独立自主的工艺装备,结合HTCC相关产品的工艺生产流程,进行生产线的整体布局设计和智能化建设,分别就产能现状仿真、布局规划、自动化建设、基于OPC和Secs/Gem等通信协议的数据采集与控制系统、数字化生产运营管理系统等方面,对生产线进行升级改造,建设HTCC生产线智能化的示范工厂,实现HTCC生产线的智能化提升,为微电子领域数字化车间的智能制造提供参考.

以铸铁排水管件毛刺的清理为研究对象,针对其生产过程中人工打磨向智能化加工的技术改革需求,利用ABB RobotStudio软件设计、构建了一机多工位的机器人打磨工作站.基于UG软件完成打磨工作站三维模型的建立,并导入RobotStudio软件中;使用机器人模型库中IRB4600-60完成工业生产过程,构建气动夹具和设计夹指机械结构,以满足相应的动作需求,并设计对应的姿态动作;为夹指机械结构、砂轮打磨机和砂带打磨机创建Smart组件和I/O信号连接实现动态效果,并设定机器人和各机械结构Smart组件的工作站逻辑;设计好虚拟仿真工作站后,对工作站进行了离线编程和仿真,最后进行现场工作站的打磨,验证了机器人打磨效果优于人工打磨.

建立了钻削加工仿真模型,并采用麻花钻对钛合金进行振动钻削试验.利用ABAQUS软件进行轴向超声振动钻削仿真,试验验证和对比分析了轴向超声振动钻削在不同加工参数下的切屑形态和钻削力.仿真与试验结果表明:随着进给量和振幅增加,钻削力增大,但进给量对钻削力的影响大于振幅;无论是进给量还是振幅的改变,对切屑形态均有影响.

The application of robots in the grinding industry can solve the problems in traditional artificial grinding, such as high labor intensity, low work efficiency, unguaranteed processing quality and serious physical injury to workers. In order to ensure the grinding quality, it is necessary to control the grinding force. The aims of this study is use PID-IMC controller to control the grinding force. Carry on the robot dynamics analysis to establish the dynamics model. Based on the principle of internal model control (IMC), PID controller is optimized and PID-IMC controller is obtained, which is used to realize the constant force control of robot grinding. Simulation and experiments results show that, the dynamics model and control method proposed in this paper have a better effect in the control of robot grinding force.

针对铸件三通管为工件,介绍了一种基于RobotStudio搭建工业机器人打磨工作站的方法,并通过实验验证空间布局及程序合理性.首先,根据工件的特殊性设计专属的夹具以及工作站;其次,设置I/O信号以及关键数据,编写程序并进行调试;最后,通过仿真数据配置实际工作站进行加工工件.实验结果表明,该方案可满足加工要求,并且在提高生产效率的同时改善了工作环境.

身管是火炮延寿的重点研究对象.运用Ansys Workbench软件对火炮实弹试验和脉冲激光加热身管试验的受热规律进行了仿真,得到两种情况下身管温度变化规律,通过对比分析发现两者温度变化规律相符.由此设计了脉冲激光加热系统,用于研究身管受脉冲高温时的温度变化规律,并进行了试验.通过对比发现仿真规律与试验结果相符,验证了此系统的可行性,在火炮身管的寿命预测、故障诊断等工作中具有一定的实际应用价值.为身管在高温脉冲作用下的相关研究提供了一种新的研究方法.

建立了球形滚压模型,考虑了工件的初始粗糙峰的力学性能、工件—工具接触面的几何形状、加工表面的实际状况以及初始加工表面粗糙峰尖端间距对滚压工具压力的影响.定义了滚压过程的特定参数对粗糙峰尖端滑移的影响,计算了在各种滚压条件下的粗糙峰尖端滑移和滚压力的最佳值,通过理论分析验证了分析结果.

针对深孔切削加工进行时,排屑效率低与钻头喉部易堵屑的问题,对BTA冷却系统冷却液出口断面速度,以及冷却液在钻头喉部的流动过程与特性进行了研究,基于计算流体动力学(CFD)与射流卷吸效应,提出了一种新型的BTA深孔钻头喉部结构.对加工时的压强和流量参数进行了分析后,修订了有限元冷却液模型的湍流强度和耗散速率,在此基础上进行了两种钻头喉部结构的排屑能力对比试验,测量了冷却液系统的冷却液出口断面流出平均速度.研究结果表明:实验时,新型喉部结构的直径38 mm BTA深孔钻头所组成的冷却系统,其冷却液出口断面流出的平均速度提高12.6％;同时,冷却液系统整体的排屑能力也得到了提高.

Robot will be used in the grinding industry widely to liberate human beings from harsh environments. In the grinding process, optimal trajectory planning will not only improve the processing quality but also improve the machining efficiency. The aims of this study are to propose a new algorithm and verify its efficiency in achieving the optimal trajectory planning of the grinding robot. An objective function has been defined terms of both time and jerk. Improved whale optimization algorithm (IWOA) is proposed based on whale optimization algorithm (WOA) and differential evolution algorithm (DE). Mutation operation and selection operation of DE are imitated in the part of initialization to process the population initialized by WOA, and then, the search tasks of WOA are performed. Motion with a constant velocity of the end-effector is considered during fine grinding. The continuity of acceleration and velocity will be achieved by minimizing jerk, and at the same time, smooth robot movement can be obtained. Cubic spline interpolation is implemented. A six-axis industrial robot is used for this research. Results show that optimal trajectory planning based on IWOA is more efficient than others. This method presented in this paper may have some indirect significance in robot business.

储存环境是影响固体推进剂性能的重要因素之一,其可能导致脱粘、裂纹等内部缺陷的产生,将严重影响推进剂的正常使用,带来安全隐患.首先,研究了固体推进剂的老化与温度的关系,以及当温度不变时,湿度与固体推进剂老化的关系,并得到了固体推进剂的最佳储存温度和湿度;其次,通过传热学的计算,得到了推进剂温度与洞库温度之间的关系.研究结果可为推进剂的储存环境优化、存储条件改善提供理论支撑.

针对射流孔几何参数对BTA深孔钻喉部流场的影响,对射流孔直径、角度与射流孔距离喉部的位置进行有限元数值模拟,提出一种最优的新型喉部结构.在设置有限元模型的湍流强度和耗散率基础上,进行不同几何参数的深孔钻头喉部结构的排屑能力对比试验,测量冷却液系统的冷却液出口断面流出平均速度.试验结果表明:最优喉部结构为φ38mm BTA深孔钻头所组成的冷却系统,冷却液出口断面流出的平均速度提高9.6％,同时提高了冷却液系统整体的排屑能力.由相似定理得出,冷却液系统的排屑能力提高9.6％.