High speed electrochemical boring

Electrochemical machining (ECM) is widely used nowadays in a great variety of processes, especially in the aero and auto industries. The main machining processes, where high tool feed rates are required, are drilling, cavity sinking, broaching and grinding. In addition, the non-equilibrium machining processes, where stationary electrodes are utilized, have important practical applications in the fields of deburring and embossing. Electrochemical honing is a non-equilibrium process. EC honing is a new technique which, in spite of being used in some industrial plants, is still not fully described, requiring more information about the process. This work presents a comparative study, between rotating and non-rotating electrodes for the enlargement of conventionally pre-drilled holes. The comparison covers the rate of metal removal, dimensional accuracy, surface finish and power consumption. The beneficial advantages of using high rotational speeds on component accuracy are verified. The results emphasize that each process has its own particular characterization, appropriate field of application and tooling system.     

高速加工技术与电主轴

高速加工机床的核心功能部件是电主轴,研究高速加工的关键技术以及电主轴的部件在设计和制造中的一些关键技术,了解相关最新技术及其发展趋势和动态,为合理选用电主轴,满足生产工艺的需求具有实践指导意义。     

Wear of silicon carbide in high speed sliding

Attritious wear of silicon carbide rubbing against a cobalt base superalloy at high speed was studied using a scanning electron microscope (SEM) and an Auger electron spectroscope (AES). The SEM study of the wear area on the silicon carbide grain showed it to be very smooth. The AES study of the groove-like marking generated by a silicon carbide grain showed a heavy concentration of carbon in areas where submicron wear debris was present. No indication of chemical reaction of the abrasive with the work material was evident. Instead, it appears that the surface atoms on the abrasive are removed preferentially, layer by layer, by oxidation under high temperature and a favorably directed shear stress.     

高速转子的低速动平衡

介绍了高速转子的分类、低速动平衡的评定标准，分别以压缩机转子和汽轮机转子为例，介绍了高速转子的低速动平衡方法。     

宽调速直流调速装置的低速自适应

介绍一种克服直流伺服系统在极低转速下的静摩擦等非线性因素的带速度自适应控制器的单一速度环调节器一速度调节器，它可使系统的调速范围达到1：10000。     

高速数控机床的结构特点

论述高速数控机床的主轴系统、进给系统、支承部件、冷却润滑系统、数控系统、接口系统和监控系统的结构特点,对认识、研究、设计及改进高速数控机床的结构有所启发和帮助。     

高速装备前瞻自适应速度优化算法

为了实现高速加工中进给速度的高速衔接,避免因加速度突变导致对数控设备的冲击,提出了一种基于插补前S曲线加减速的前瞻自适应速度优化算法。该算法能够根据加工段的过渡情况自动调节预读段数。以进给速度最大化为目标,在预读段衔接进给速度限制和加工过程平滑减速的约束条件下,根据离散化S曲线加减速规律求解最优衔接进给速度。将求得的最优衔接进给速度作为相应加工段的实际末速度,来实现加工段的速度控制。给出了该算法在高速数控系统中的实现方法,并在管切割数控系统中得到了应用。实验结果表明,该算法能够实现进给速度的高速、平滑衔接,满足高速加工的要求。     

High speed nano-metrology

For manufacturing at the nanometre scale a method for rapid and accurate measurement of the resultant functional devices is required. Although atomic force microscopy (AFM) has the requisite spatial resolution, it is severely limited in scan speed, the resolution and repeatability of vertical and lateral measurements being degraded when speed is increased. Here we present a new approach to AFM that makes a direct and feedback-independent measurement of surface height using a laser interferometer focused onto the back of the AFM tip. Combining this direct height measurement with a passive, feedback-free method for maintaining tip-sample contact removes the constraint on scan speed that comes from the bandwidth of the z-feedback loop. Conventional laser reflection detection is used for feedback control, which now plays the role of minimising tip-sample forces, rather than producing the sample topography. Using the system in conjunction with a rapid scanner, true height images are obtained with areas up to (36 × 36) μm(2) at 1 image/second, suitable for in-line applications.     

High speed tooling

Creating tooling for a new product can be a long and expensive process. The authors explore the use of rapid prototyping technology for producing metal tools     

Vehicle speed measurement: Cosine error correction

Although laser devices are commonly used to measure distances and vehicle speed in traffic safety-related studies, they suffer from a drawback known as the cosine effect. Furthermore, such traffic safety studies analyze both vehicle speed and a large amount of geographical data. As such, the development of efficient and cost-effective techniques for correcting the cosine error and managing the data involved in vehicle speed studies are needed. This paper presents an algorithm for correcting cosine error based on a Geographic Information System (GIS) that makes use of vehicle speed measurements and Global Positioning System (GPS) coordinates. An experiment using more than 350 vehicle speeds was conducted to test the algorithm, and the case study shows that controlling the quality of laser-measured speeds in order to suppress low quality data or correct measurement errors due to the cosine effect is very useful.     

数控系统速度曲线研究

加减速控制方法是现代高精度、高性能数控系统中的重要环节,现代加减速控制方法主要分为梯形速度曲线与S形速度曲线。通过对梯形速度曲线与S形速度曲线的比较,可知S形速度曲线在减小冲击和振动方面更具有优势。接着对S形速度曲线进行了深入研究,给出了加速度、速度和位移各个时间段的计算公式。由于在实际插补计算时,会有各种特殊情况出现,所以又对各个特殊情况进行了讨论,得出各个特殊情况的计算公式。最后给出了程序段预处理过程流程图和程序段插补过程流程图。     

高速电主轴的热特性分析

分析了高速电主轴中电机的损耗发热和轴承的摩擦发热，并提出了减小其损耗和改进其冷却状况的措施，为电主轴的热稳定性的解决奠定了理论基础。     

Cutting speed modelling in ball nose milling applications

Cutting speed is a key factor that influences machined surface quality and tool life in milling. To date, the study of its distribution over a machined surface has not been established. This paper presents a mathematical model to evaluate cutting speed on the machined surface in 3-axis ball nose milling. The approximation errors introduced by surface shape, step-over and CNC interpolation are analysed. The model is used to predict visible areas which have different colour intensities on finished surfaces in the machining of a wood-plastic composite. A good agreement is obtained between the prediction and experimental results.     

Acquisition speed comparison of microscope software programs

Reliable software is a prerequisite for successful operation of a modern wide field fluorescence microscope. When used for live cell imaging, acquisition speed is of particular interest. This is both because biological processes can be highly-dynamic, and to avoid unnecessary photobleaching and phototoxicity of living samples. This article shows that besides the hardware (microscope) components themselves, the acquisition control software is an important influencing factor of speed performance. We tested and compared the speed performance of five different generic applications (Image-Pro Plus, MetaMorph, Micro-Manager, SlideBook, and Volocity) using typical experimental setups involving a single specific state-of-the-art fluorescence microscope configuration. The test measurements included multichannel experiments, z-stacking, burst acquisition, as well as combinations of these measurements with time-lapse acquisitions. The measured data provided values for guiding the testing and analysis of other microscope systems with similar configurations. Despite the identical hardware settings, significant and surprisingly large speed differences were evident among the various software applications. Additionally, no application was identifiable as the fastest in all tests. Our work pinpoints the importance of the control software in determining a system's "real" maximal imaging speed. The study could serve as basis for further tests, eventually influencing the system selection criteria for speed-sensitive applications.     

Computation of flows around a high speed catamaran

A numerical study is carried out to clarify the characteristics of flow fields and breaking phenomena around a high speed catamaran hull advancing on calm water. Computations are carried out for Froude numbers between 0.2 and 1.0 and for ratios of the distance between hulls to the catamaran length varying between 0.2 and 0.5 for a mathematically defined Wigley hull. A Navier-Stokes solver which includes the nonlinearities of free surface conditions is employed. Computations are performed in a rectangular grid system based on the Market & Cell method. For validation, present computation results are compared with existing experimental results. As an application, the results of the displacement catamaran are used for the breaking analysis.     

高速入水子弹气动发射架设计建模

研究了一种用于研究子弹在不同角度高速入水的气动发射架。主要从发射架结构构成、发射原理分析和计算机模拟等方面对发射架进行分析。建立了子弹发射过程的数学模型,选用Matlab软件对模型分析求解,得出了子弹速度的时域变化曲线。通过改变发射边界参数,对比得出各参数对子弹发射的影响。对子弹在不同角度下高速入水研究进行技术储备和参考,同时也为气动发射架的设计提供理论依据。     

新型摆杆减速器的研究

本文给出了一种新型摆杆减速器的结构组成和工作原理,能过对该减速器摆机构运动的分析,推导出了内齿圈齿廓的方程式,同时对机构的传动特性进行了讨论。通过对机构和初步试制和试验,证明了理论分析的正确性,为这种减速器的进一步研究打了基础。     

SPH method applied to high speed cutting modelling

The purpose of this study is to introduce a new approach of high speed cutting numerical modelling. A Lagrangian smoothed particle hydrodynamics (SPH)-based model is carried out using the Ls-Dyna software. SPH is a meshless method, thus large material distortions that occur in the cutting problem are easily managed and SPH contact control permits a “natural” workpiece/chip separation. The developed approach is compared to machining dedicated code results and experimental data. The SPH cutting model has proved is ability to account for continuous to shear localized chip formation and also correctly estimates the cutting forces, as illustrated in some orthogonal cutting examples. Thus, comparable results to machining dedicated codes are obtained without introducing any adjusting numerical parameters (friction coefficient, fracture control parameter).     

ATmega162单片机与交流电机调速控制研究

在交流电机调速控制系统里,可以利用ATmega162单片机进行通信及脉宽调制,并且需要开发单片机与上位计算机进行串行通信的控制界面.给出了交流电机移相调速控制及脉宽调制在ATmega162中的编程实现过程,阐述了使用C语言编写的单片机串行通信接口程序,并说明了利用Delphi编写计算机串行通信界面的方法.     

高速及超高速磨削加工的绿色特性

对高速及超高速磨削加工的绿色特性进行了分析和探讨,并通过两个具体的加工实例,将普通磨削加工方法与高速及超高速加工方法的有关参数进行了比较,证明了高速及超高速磨削加工方法在制造工艺方法选择中所具有的绿色特性优势以及可观的应用前景.