Fabrication of off-axis aspheric surfaces using a slow tool servo

Off-axis aspheric surfaces have been widely applied in optical systems, but it is difficult to fabricate this kind of optical surface with high quality. Slow tool servo is one of the methods for turning off-axis aspheric surfaces on-axis, which have a large travel range without an additional device. This paper presents a theoretical and experimental investigation on the 3D surface generation in single point diamond tuning using slow tool servo. The form error of off-axis paraboloid caused by tool centering error is analyzed and verified by cutting experiment.     

Design and development of a precision machine tool using counter motion mechanisms

In order to meet the increasing demand for high-quality miniature parts made of a wide variety of materials, the electronics, biomedical and optical industries are moving towards micro/nano-machining. Currently, mechanical micromachining can only be performed under very low feed rates and small depth of cut, which makes it very difficult to reach reasonable productivity. To cope with the low-productivity problem for micro/nano-machining of high-precision molds or miniature parts, a highly accurate and productive machining center has been designed and developed in this paper. The developed machine tool is equipped with counter balance axes, and each axis is driven at its center of gravity to achieve high acceleration/deceleration without causing any vibration. This paper describes the theoretical and practical background of the design of the machine tool and its control and measurement system. Then, experiments are carried out to evaluate the machining performance of this designed machine tool.     

一种高精度挤压机电气控制系统的设计与实现

本文结合某冲压线的一台高精度挤压设备,简要分析如何实现西门子可编程控制器与交流伺服系统的通讯和控制,以及在高精度定位系统中的应用。本文详述了此类高精度挤压机的设计原理和实际工作性能。     

多体系统理论在数控加工精度软件预测中的应用

基于多体系统理论和虚拟加工技术的基本原理,阐述了多体系统的特征矩阵,研究了数控机床刀具成形函数和空间误差模型,提出和分析了机床加工精度软件预测的建模方法,最后为了验证所述精度预测方法的有效性,进行了软件预测和实体加工的加工精度比较实验.     

高精度板材时效炉的导流结构设计与应用

为实现高精度板材时效热处理炉的炉温均匀性要求,通过加装导流结构并用数值模拟的方法优化其结构参数,然后对模拟结果进行了炉温均匀性测试.结果表明:导流结构可将时效炉的温度均匀性偏差控制在±1.5℃范围内,且模拟结果与实际炉温均匀性测量结果相符,即导流结构设置合理,可满足时效炉温度均匀性的控制要求.     

真空低压渗碳炉高精度温控系统的设计与应用

设计了一种基于组态王6.55软件的真空低压渗碳上位机监控系统,通过组态王软件与山武仪表DCP31之间的Modbus通讯,利用仪表自带的二自由度(2-DOF)PID功能,实时进行PID修正保证控温的精确度。将渗碳工艺中的变量如C₂H₂、NH₃和N₂的流量控制及渗碳扩散时间、脉冲次数、保温时间和淬火方式等一系列参数固化成配方形式,供用户调用和修改。这一软件平台的设计及应用减少了操作人员的误操作和复杂程度,大大提高了低压渗碳的热处理品质。     

多功能自动焊接机床控制设计与分析

利用步进电机分别对焊枪和工件的运动进行联合控制,实现了复杂空间曲线接缝的焊接。设计了伺服控制软硬件系统,并对数学模型和插补算法进行了叙述,最后对系统精度进行了分析,并提出了改善措施。     

基于单片机的交流电机软启动器及其在机床电力拖动中的应用

0 引言。众所周知，三相异步电动机以其低成本、高可靠性和易维护等特点，被广泛应用在各个行业。特别是机床设备中，它作为一种主要的动力设备，常常用来拖动主轴、工作台、冷却泵、油泵等装置。但是它在直接启动时，由于启动电流高达额定电流的5～7倍，所以会对电网及负载造成很大的冲击，影响了周边电器的工作，增加了机械传动部件的磨损，降低了设备的寿命。     

基于高精度Fuzzy控制算法的校直机液压伺服系统的仿真与应用研究

模糊控制器以其结构简单、鲁棒性强、不需要被控对象的数学模型及粗调快速等优点被广泛应用于工业控制系统。但是,常规模糊控制器也存在控制精度不高、"调节死区"等问题。本文通过对普通模糊控制器的改进,研究出一种高精度模糊控制策略,并将其应用于校直机液压伺服控制系统。最后对控制系统进行了仿真研究,取得了较为满意的效果。仿真结果表明,与常规的模糊控制算法相比,该控制算法具有超调小,响应快等优点。     

A machining test to calibrate rotary axis error motions of five-axis machine tools and its application to thermal deformation test

This paper proposes a machining test to parameterize error motions, or position-dependent geometric errors, of rotary axes in a five-axis machine tool. At the given set of angular positions of rotary axes, a square-shaped step is machined by a straight end mill. By measuring geometric errors of the finished test piece, the position and the orientation of rotary axis average lines (location errors), as well as position-dependent geometric errors of rotary axes, can be numerically identified based on the machine׳s kinematic model. Furthermore, by consequently performing the proposed machining test, one can quantitatively observe how error motions of rotary axes change due to thermal deformation induced mainly by spindle rotation. Experimental demonstration is presented.     

改善线切割加工精度与表面质量的方法

从材料的残余应力、加工工艺、机床自身因素入手,分析了快走丝线切割在模具型腔和型芯的加工过程中影响加工精度和表面质量的主要因素,提出了提高线切割加工精度和表面质量的改进措施,在实际加工过程中效果显著.     

电机电流的检测及其在模糊智能加工系统中的应用

分析了进给电机电流与相应的切削分力之间关系,用最小二乘法建立了它们之间的数学模型,以进给电机电流为监测切削负载的手段,实现了基于模糊芯片的铣削过程的模糊控制。     

Design and control of a novel hybrid feed drive for high performance and energy efficient machining

Achieving sustainability in manufacturing requires that the energy consumption of manufacturing machines be reduced without unduly sacrificing their speed and accuracy. This paper presents the design and control of a novel feed drive whose actuation method and drive configuration change depending on the mode of the machining operation. During rapid traverse, the table is driven at its center of gravity using a linear motor. When cutting begins, the table automatically couples to a motor-driven shaft, while the linear motor provides active vibration damping and quasi-static error compensation. Improvements in speed, accuracy and/or energy efficiency over conventional drives are experimentally demonstrated.     

一种高效铣削弹性夹具设计与应用

为了加工一种具有特殊结构的汽车用高度调整销,解决加工时零件对称平面的对称性与平行性问题,设计了一种可一次装夹多件零件的弹性夹具。通过对夹具的结构设计与夹紧力分析,充分保证了夹具装夹的可靠性与高效性。实践证明,该夹具的使用提高了零件的加工效率,同时降低了零件的废品率。     

自动化三维精密测量技术及其在锻压领域的应用

面扫描三维测量技术具有非接触、测量速度快、精度高等优势,在锻压领域具有巨大的应用潜力.但是通用的面扫描三维测量设备在测量过程中易受测量规划、数据处理等人为因素影响,测量精度难以保证.为解决此问题,提出一种基于面扫描和六自由度机器手的自动化三维测量技术,该技术由六自由度机器手、三维测量头、控制系统等组成,能够充分利用机器手运动灵活、工作范围大的特点和面扫描测量速度快、精度高的优势.此外,该技术采用了一种基于矩阵直积的手眼标定算法,实现了多次测量数据的高精度自动拼合.实际应用表明,该技术能够实现复杂锻件等工业产品的快速、精确、自动三维测量和精度检测.     

Modelling vibration transmission in the mechanical and control system of a precision machine

The relative vibration between tool and workpiece factors significantly to the performance of a precision machine. This paper develops a model for predicting the vibration transmission from two major excitation sources, ground vibration and fluid bearing force, to the tool and the workpiece position through the mechanical and control system of a precision machine. We synthesised the frequency response functions obtained from a finite element analysis of the machine to create transmissibility matrices that define the dynamic behaviours of the electromechanical system. The validity of the developed model was checked by comparing the measured relative vibrations to the results calculated from the measured excitations.     

一种高效型金刚石锯片开刃机设计

本文在对目前整体烧结金刚石锯片侧刃开刃过程进行实验研究的基础上，指出合适的开刃形式与合理的开刃参数对开刃过程有显著影响。进而设计出快速的锯片装卸方案，并针对影响开刃工序成本与效率的其他重要环节进行了研究，提出了解决方案。实验结果表明，改进型开刀机大幅度提高了工作效率，降低了加工成本。与吃入式开刃形式相比，抹式开刃是一种更为合理的开刃形式。     

Development of a micro-punching machine and study on the influence of vibration machining in micro-EDM

This paper describes the development of a novel micro-punching machine that is capable of producing precision micro-holes. A significant feature of this machine is to fabricate the micro-punch and then the micro-die in the same machine, totally eliminating the eccentricity between the punch and the die when punching is proceeded. By applying vibration machining technique, we can decrease the possibility of electric short-circuiting during the micro-EDM process. The utilization of a proportional solenoid as the power unit of the micro-punching machine and as the source of vibration is found to be a successful attempt. Experiments to punch micro-holes with diameters of 0.1 and 0.2 mm on an SUS 304 stainless steel strip with 0.1 mm in thickness were carried out. The results show that the performance of this machine and the geometry of punched micro-holes are satisfactory.     

高压燃气管道焊机消磁技术及应用

利用电焊机对施工现场钢管进行消磁处理,具有行之有效、方便快捷等特点,可有效解决现场焊接施工磁偏吹现象,且无需增加额外设备,能够快速消除钢管的剩磁。阐述消磁技术的原理及特点,分析了电焊机消磁技术的工艺要点,并探讨消磁过程需要注意的问题。     

Experimental studies on drilling tool load and machining quality of C/SiC composites in rotary ultrasonic machining

Carbon fiber reinforced silicon carbide matrix (C/SiC) composites have great potential in space applications because of their excellent properties such as low density, superior wear resistance and high temperature resistance. However, the use of C/SiC has been hindered seriously because of its poor machining characteristics. With an objective to improve the machining process of C/SiC composites, rotary ultrasonic machining (RUM) and conventional drilling (CD) tests with a diamond core drill were conducted. The effects of ultrasonic vibration on mechanical load and machining quality were studied by comparing the drilling force, torque, quality of holes exit and surface roughness of drilled holes between the two processes. The results showed that the drilling force and torque for RUM were reduced by 23% and 47.6%, respectively of those for CD. In addition, the reduction in drilling force and torque decreased gradually with increasing spindle speed, while they changed slightly with increasing feed rate. Under identical conditions, RUM gave better holes exit than CD. Moreover, because of the lower lamellar brittle fracture and pit originating from carbon fibers fracture, the roughness of surface of drilled holes obtained with RUM was lower than CD and the maximum reduction was 23%.