[设备健康管理]基于机床信息的加工过程刀具磨损状态在线监测

为实现刀具磨损状态的在线监测,提高监测系统的实用性,提出一种基于机床信息的加工过程刀具磨损状态在线监测方法。采用OPC UA通信技术在线采集与存储数控机床信息,得到与磨损相关的机床内部过程信息,并基于这类信息与相应的刀具磨损信息,利用卷积神经网络建立了刀具磨损状态识别模型。应用案例证明了该方法的监测性能,与其他传统监测方法相比,该方法更适用于实际的生产加工。     

立铣加工刀具状态监控技术评述

综述了立铣加工刀具状态监控技术的研究现状.刀具状态监控技术在工业上的应用涉及到两种关键系统:一是具有不同智能水平的各种传感器系统,另一个是能把机床控制器所用的控制信号综合成能发觉刀具破损和反映刀具磨损程度信号的过程监控系统.这两种系统相结合,就能实现刀具状态监控系统在工业加工环境的应用.     

Development of meso-scale milling machine tool and its performance analysis

To overcome the shortcomings of current technologies for meso-scale manufacturing such as MEMS and ultra precision machining, this paper focuses on the investigations on the meso milling process with a miniaturized machine tool. First, the related technologies for the process mechanism studies are investigated based on the analysis of the characteristics of the meso milling process. An overview of the key issues is presented and research approaches are also proposed. Then, a meso-scale milling machine tool system is developed. The subsystems and their specifications are described in detail. Finally, some tests are conducted to evaluate the performance of the system. These tests consist of precision measurement of the positioning subsystem, the test for machining precision evaluation, and the experiments for machining mechanical parts with complex features. Through test analysis, the meso milling process with a miniaturized machine tool is proved to be feasible and applicable for meso manufacturing.     

机床网络化生产管理与监控系统开发

面向车间层级的网络化协同加工的实际需求,开发一套软/硬件一体化的机床网络化生产管理与监控系统,实现远程客户或企业管理者通过网络对车间机床操作者加工任务的进度管理与生产监控,是网络化制造中机床资源的共享和车间层机床设备生产过程的管理与监控的软/硬件支持平台.     

Smart Cutting Tools and Smart Machining: Development Approaches,and Their Implementation and Application Perspectives

Smart machining has tremendous potential and is becoming one of new generation high value precision manufacturing technologies in line with the advance of Industry 4.0 concepts. This paper presents some innovative design concepts and, in particular, the development of four types of smart cutting tools, including a force-based smart cutting tool, a temperature-based internally-cooled cutting tool, a fast tool servo (FTS) and smart collets for ultraprecision and micro manufacturing purposes. Implementation and application perspectives of these smart cutting tools are explored and discussed particularly for smart machining against a number of industrial application requirements. They are contamination-free machining, machining of tool-wear-prone Si-based infra-red devices and medical applications, high speed micro milling and micro drilling, etc. Furthermore, implementation techniques are presented focusing on: (a) plug-and-produce design principle and the associated smart control algorithms, (b) piezoelectric film and surface acoustic wave transducers to measure cutting forces in process, (c) critical cutting temperature control in real-time machining, (d) in-process calibration through machining trials, (e) FE-based design and analysis of smart cutting tools, and (f) application exemplars on adaptive smart machining.     

基于信息融合技术的加工过程监测系统研究

加工过程状态的监测与控制是提高机床智能化的重要研究内容,为实现加工过程的智能化监测与控制必须以多传感器及多传感器信息融合技术为基础.提出了一种基于粗糙集理论和神经网络的多传感器智能信息融合方法,该方法将粗糙集理论作为实现多传感器数据融合的方法,同时针对粗糙集理论只能处理离散数据的问题.提出了使用自组织特征映射网络对传感器采集数据进行离散化及聚类处理的方法,针对粗糙集理论在决策融合处理方面的不足,提出了使用BP神经网络来实现决策规则的有效融合,分析了该方法的原理、关键技术及实现方法,为后期的进一步的研究和应用打下基础.     

谈数控机床刀具的监控技术

数控机床刀具中的检测与监控就是采用检测与监控系统通过传感和分析处理相关信息,从而对数控机床运行状态和加工过程进行检测与控制,保证数控机床的加工质量,防止产生废品,减少废品率,提高机械加工生产率,提高加工过程的安全性,优化配置制造资源。而检测与监控系统的成败主要取决于系统所收集的信号即有关监控参数的正确选择,也取决于其物理结构上的传感器和监控器以及硬件和软件系统。     

Tool condition monitoring in an end-milling operation based on the vibration signal collected through a microcontroller-based data acquisition system

Machine condition plays an important role in machining performance. A machine condition monitoring system will provide significant economic benefits when applied to machine tools and machining processes. Development of such a system requires reliable machining data that can reflect machining processes. This study demonstrates a tool condition monitoring approach in an end-milling operation based on the vibration signal collected through a low-cost, microcontroller-based data acquisition system. A data acquisition system has been built through interfacing a microcontroller with a signal transducer for collecting cutting vibration. The examination tests of this developed system have been carried out on a CNC milling machine. Experimental studies and data analysis have been performed to validate the proposed system. The onsite tests show the developed system can perform properly as proposed.     

Development of meso-scale milling machine tool and its performance analysis

To overcome the shortcomings of current technologies for meso-scale manufacturing such as MEMS and ultra precision machining, this paper focuses on the investigations on the meso milling process with a miniaturized machine tool. First, the related technologies for the process mechanism studies are investigated based on the analysis of the characteristics of the meso milling process. An overview of the key issues is presented and research approaches are also proposed. Then, a mesoscale milling machine tool system is developed. The subsystems and their specifications are described in detail. Finally, some tests are conducted to evaluate the performance of the system. These tests consist of precision measurement of the positioning subsystem, the test for machining precision evaluation, and the experiments for machining mechanical parts with complex features. Through test analysis, the meso milling process with a miniaturized machine tool is proved to be feasible and applicable for meso manufacturing. __________ Translated from Chinese Journal of Mechanical Engineering, 2006, 42(11): 162–167 [译自: 机械工程学报]     

Research into integrated design and manufacturing based on STEP

This paper discusses a typical STEP-compliant manufacturing environment, which effectively integrates two systems. The first generates native data that retain the information needed to machine a part on a particular machine tool, whereas the second carries out optimization for machining parameters using the dispatched information from the first system. The related research work is divided into four areas, feature generation, macro process planning, micro process planning, and machining execution. The main part of the paper is devoted to reviewing the most recent research publications. The publications have been organized into the four areas as mentioned above. The discussion section that follows looks at the STEP-compliant research from the perspectives of industrial adoption, feature recognition for process planning, challenges in STEP-enabled inspection and STEP-NC controllers.     

基于OpenInventor的六自由度钻铣机加工仿真研究

针对面向航空装配的六自由度钻铣机,利用0penInventor结合VS2008软件构建其加工仿真系统。以虚拟现实语言VRML为数据接口,从UG和CATIA中分别导入机床本体和加工零件,完成机床的三维运动学仿真。在研究0penInventor现有的挤压函数基础上,结合实际加工过程,给出改进算法,得到多轴加工过程中理想的刀具扫描体。最后利用生成的刀具扫描体完成加工仿真以及加工过程中的碰撞检测。通过验证,系统可以实现六自由度钻铣机的加工仿真,仿真效果真实,沉浸感强。此方法同样适用于任何形式多轴机床的加工仿真。     

介观尺度微型铣床开发及性能试验

针对微机电系统(Microeletro mechanical system, MEMS)技术和超精密加工技术局限,开展面向介观尺度微细铣削技术的研究。首先根据介观尺度铣削的加工特点,对其机理研究的关键问题进行详细的分析和讨论,提出微细铣削理论的研究重点及研究方法。然后在分析微细铣削成形条件和加工要求的基础上,开发微型铣床系统,并对系统各组成子系统及性能指标进行描述。最后开展机床加工性能评估试验,通过精度测量、误差分析和误差补偿提高工作台的定位精度达到1.62 μm,采用直径0.127 mm铣刀开展微铣削试验,通过表面粗糙度测量和同心圆切削试验评估机床的加工精度,在此基础上通过复杂零件加工实例进一步说明机床的加工能力,论证小型化机床加工技术的可行性和实用性。     

智能机床发展现状与技术体系框架

智能机床成为机床装备发展的趋势。在介绍国内外智能机床的研究现状的基础上,分析目前智能机床技术研究的三个问题,提出智能机床的狭义和广义定义;给出智能机床的包括人计机的协同性、整体与局部的协调性、智能的恰当性与无止性、自学习及其能力持续提高性、自治与集中的统一性、结构的开放性和可扩展性、制造和加工的绿色性、智能的贯穿性八个智能技术特征;阐述包括以人为中心的人计机动态交互功能、三个基本功能——执行智能功能、准备智能功能、维护智能功能的智能功能特征,以及功能之间的相互关系;建立八个理论与技术的智能机床技术理论框架,包括人计机一体化融合理论与技术、多源信息的感知理论与技术、智能决策理论与技术、智能执行理论与技术、智能维护理论与技术、智能机床综合能力评价理论与技术、智能机床标准化技术、智能机床支撑技术等,形成了智能机床的技术体系框架,同时指出上述内容将随着技术的进步和应用的深入不断充实和丰富。     

Monitoring and control of tools in multifunctional machine tools

Machining centers and multifunctional machine tools are used in computerized integrated production. They are equipped with a large number of cutting tools for production of a specific batch of parts. In such automatic systems, monitoring and control systems replace the human operator. Monitoring of the state of machining systems is essential today in monitoring and control of the machining operations [1, 2]. It is important to create monitoring systems to support reliable tool operation in multifunctional machine tools. The goals of such systems are to minimize the damage from serious disruption of tool operation and to ensure timely tool replacement. To that end the multifunctional machine tools and/or the numerical control system must be equipped with sensors and various monitoring devices. A strategy must be developed for the prevention of disruption of the machining process and tool failure.     

并联机床数控加工过程仿真方法的开发

针对六自由度数控铣床－并联机床的数控加工,本文提出一种新的加工过程仿真算法。该算法基于观察坐标系,利用扫描线算法在精度范围内表示工件和刀具,从而将复杂的三维布尔运算简化的一维布尔运算。笔者在微机上利用ＶＣ＋＋,根据这种新算法,开发出并联机床数控加工过程仿真系统,实现了并联机床数控加工过程仿真。     

Dynamic wireless passive strain measurement in CNC turning using surface acoustic wave sensors

Wireless, passive and dynamic surface acoustic wave (SAW) strain sensors are especially advantageous in applications with harsh environments where complex force measurements are required. High frequency multiple axis force measurement during machining processes typically requires state-of-the-art piezoelectric dynamometer technologies. Integrating dynamometers and their associated measurement chains into the machining environment typically requires significant modification to the machine structure. In this paper, SAW sensors were developed for process monitoring operations. Single-axis continuous and interrupted cutting investigations were carried out using the SAW technology installed on cutting tool holders demonstrating high dynamic bandwidth strain measurement. SAW dual-axis oblique cutting measurements were carried out where four SAW sensors were set up as two differential pairs each measuring a single axis of applied force. Improvements in sensitivity and cross-talk compensation has been realised. High-frequency wireless passive realtime process signals are presented from a passive wireless SAW force measurement system successfully integrated into an LT15 Okuma machining centre. The paper aims to present wireless passive SAW technology as a potentially platform changing approach for process and tool condition monitoring applications in the future.     

ESPRIT- and HMM-based real-time monitoring and suppression of machining chatter in smart CNC milling system

Suppression of machining chatter during milling processes is of great significance for surface finish and tool life. In this paper, a smart CNC milling system integrating the function of signal processing, monitoring, and intelligent control is presented with the aim of real-time chatter monitoring and suppression. The algorithm of estimation of signal parameters via rotational invariance techniques (ESPRIT) is adopted to extract the frequency characteristics of acceleration signals, and then, cutting state is categorized as stable state, chatter germination state, and chatter state based on amplitude-frequency characteristics of identified acceleration signals. The model of chatter identification is acquired by training a hidden Markov model (HMM), which combines acceleration signals and labeled cutting state. To implement real-time chatter suppression, the algorithm of fuzzy control is integrated into a smart CNC kernel to determine the relationship between cutting force and spindle speed. Furthermore, spindle speed of machine tool could be adjusted timely in the presented system once the chatter is identified. Finally, the effectiveness of the proposed real-time chatter monitoring and suppression system is experimentally validated.     

New tool-workpiece setting up technology for micro-milling

A major issue in micromilling is the setting up with the necessary accuracy the work coordinate system on the machine. The spindle thermal stability during the setting up procedure make this a very difficult task. Thus, it is essential to develop new tool setting up technology to increase the process productivity, reduce machine setting up times and errors, and at the same time improve the precision and quality of machined components. The paper presents a cost-effective and reliable method for setting up the work coordinate system for micro-milling operations employing an on-line tool–workpiece voltage monitoring system. The viability of the proposed method was verified in a series of experiments conducted on an ultra-precision micromilling machine centre. The experimental trials involved the machining of test parts in brass with cutters 100 and 200 µm in diameter. The results of these experiments were analysed and compared with the capabilities of currently available methods and technologies on micro milling machine tools for condition monitoring and setting up the working coordinate systems. Finally, conclusions are made about the effectiveness of the proposed new tool-workpiece setting up technology for micro milling.     

我国高速加工技术现状及发展趋势

高速加工是以较快生产节拍进行加工 ,提高切削和进刀速度是高速加工技术的重要环节。高速加工技术的发展涉及到零件毛坯、刀具、机床、自动控制与检测等多种技术的综合优化 ,需要变革传统的机加工工艺路线。我国引进的轿车零部件数控自动生产线上已广泛应用高速加工技术 ,其主要目的是在确保产品质量的前提下 ,尽量缩短零件的机加工工艺路线 ,加快生产节拍 (轿车发动机生产节拍已缩短为 30秒 ) ,满足轿车高质量、高速率、低成本、大批量、社会化生产的技术要求。高速加工技术必将带动零件毛坯制造、刀具 (工具 )、数控机床、自动控制、在线检测、材料等技术的发展与进步。随着我国制造业加快融入全球化生产制造体系 ,预计高速加工技术将在信息化、柔性化机械加工领域得到进一步发展和推广应用     

A manufacturing model of helical groove on rotary burr and a universal post processing method

A systematic machining theory and precision method to determine cutter location in a grinding system is presented for rotary burr. First, the helical cutting edge on various kinds of revolving surfaces is built. Then, based on the geometry model of the helical cutting edge, the smooth spiral rake surface with constant normal rake angle and flank surface can been formed during the one-pass grinding process by this method. No interference between the grinding wheel and workpiece happens by the wheel special rotation. The method has the characteristic of detaching the grinding wheel path solution from specified machining conditions. The grinding wheel path is suitable for different NC machine tools through post processing. Meanwhile, a mechanism kinematic model of the NC machine tool is built, and a generalized algorithm for post-processing of multi-axis NC machine tools is presented. This model is applied to arbitrary configuration of NC machine tool, and the motion value for each axis will be generated by the inputting structure and motion parameters of the machine tool. The model, together with the machining method mentioned in this paper, make the calculation and generation of the grinding wheel path simpler and universal. At last, the validity of the method given in the paper is identified by an example of grinding.