基于计算机视觉的数字刀具测量系统研究

刀具的几何参数是影响数控机床加工精度和生产效率的重要因素。研究了基于计算机视觉检测技术的高精度刀具测量系统,分析了运行原理和功能模块,对关键技术做了论述。系统实现了对刀具的刀尖切削特征点、圆弧半径和切削角参数的自动精确测量,并将数值反馈到数控机床刀具数据库,具有较高的效率、精度和自动化程度。实验结果证明,系统测量重复性精度可达3μm。     

数控加工仿真系统的真实性研究

数控机床加工技术的程序编制,是采用数控自动编程软件对二维的零件图样进行三维造型设计,然后利用软件自动生成加工程序,并将生成的加工程序送到数控机床进行零件加工。目前常用的数控自动编程软件有MasterCAM、CAXA、NX和Pro／ENGIN旺R等软件。对复杂零件的加工,则大都是采用软件进行计算机建模和仿真,模拟数控机床实际的加工方法和加工路线。这不仅能检验数控代码的正确性,     

基于数据融合的数控机床故障诊断技术研究

由于工作环境恶劣、加工零件复杂等多方面因素,数控机床工作期间经常会出现各种故障.如若相关故障未能及时发现并得到 有效处理,则势必影响正常工作的进行,对于企业也会造成一定的损失.故此次就数据融合角度探讨针对数控机床故障的诊断技术,以期对相关单位有所帮助.     

数控车床定位精度的激光检测法

数控机床的定位精度是反映数控机床控制特性和加工质量的重要指标,直接决定着零件的加工精度。如果机床的定位精度超差,则会导致加工出的零件不合格,这也直接影响了数控机床性能与功能的发挥。为了快速、准确检测出机床的定位误差并进行误差补偿,阐述了利用双频激光干涉仪进行数控机床定位精度检测的方法。     

数控机床在线检测技术

数控机床是现代高科技发展的产物,每当一批零件开始加工时,有大量的检测需要完成,包括夹具和零件的装卡、找正、零件编程原点的测定、首件零件的检测、工序间检测及加工完毕检测等.     

MasterCAM编程和CNC数控铣床巧妙结合在雕刻加工中的应用

该文通过对圆弧曲面数控雕刻加工的实例表述,给出了圆弧曲面数控雕刻的编程加工应用步骤,在圆弧曲面数控雕刻加工中,针对于编程软件的特点和数控铣床的特点,采用了灵活实用编程方案和可靠有效的数控加工工艺,从而保证零件加工质量和加工效率,也使企业经济效益和生产水平得以提高。     

基于五轴数控机床的激光在线检测方法研究

在制造行业中,零件的质量检测通常采用手工检测和离线检测,随着激光技术的发展,激光在线检测逐渐进入零件的质量检测领域;文中针对传统的零件质量检测方法的不足,分析了目前国内外激光检测技术和数控机床在线检测技术的发展态势,探讨了基于五轴数控机床的激光在线检测方法及其在检测路径设计过程中的一些亟待解决的技术问题;该方法基于光学三角测量原理,将零件加工场所和检测场所统一于数控机床,从而提高了检测活动的效率和检测结果的准确性。     

基于机器学习的零件加工在线监测研究

针对数控机床执行零件加工时,因加工刀具磨损状态监测能力不足,刀具未能及时更换导致的零件加工质量偏低、合格品零件加工速率降低的问题,提出将极限学习机网络与自编码器相结合,构建ELM-AE模型,对零件加工的刀具磨损状态进行实时监测;为适应机床零件的实际加工情况,增加模型的实际监测效果,提出基于Coral距离构建刀具磨损状态特征迁移模型,对不同工况下的振动特征区域进行迁移,提高监测模型的实际应用性能;最后经过模型编码和振动信号采集设备选型,对模型进行性能验证实验。结果表明,设计的模型能够应对不同工况下的刀具磨损状态监测,在单一工况下,刀具磨损状态判断准确率最低为99.50%;用A工况进行训练用B工况进行测试,刀具磨损状态判断准确率最低为98.75%.综上所述,模型基本能够实现对零件加工过程中的刀具磨损状态的在线监测。     

调节装置盘加工方法设计

对于形状复杂、精度要求高的零件,通常采用数控机床来完成加工。数控加工是由数控系统在程序控制下自动完成的,而程序编制的关键是计算刀具的运动轨迹,即计算加工轮廓的基点和节点坐标。数控系统一般只提供直线插补和圆弧插补两种功能,对于非圆的平面曲线ｙ＝ｆ（ｘ）,则按编程的允许误差,用直线或圆弧逼近轮廓曲线,计算出逼近直线或圆弧与轮廓曲线的交点或切点的坐标,当采用圆弧作为插补段时,还要计算出各段圆弧的圆心坐标。 一、调节装置盘加工的手工编程与自动编程 如图１所示的调节装置盘,表面上均布六个阿基米德螺旋槽,其起…     

数控加工仿真系统的真实性研究

数控机床加工技术的程序编制,是采用数控自动编程软件对二维的零件图样进行三维造型设计,然后利用软件自动生成加工程序,并将生成的加工程序送到数控机床进行零件加工。目前常用的数控自动编程软件有MasterCAM、CAXA、NX和Pro/ENGINEER等软件。     

马波斯E32R测量仪在大型发动机缸体加工中的应用

为了提高数控镗铣床在加工大型发动机缸体时的关键尺寸的精度,在机床上设计安装了马波斯（Marposs） E32R测量仪,本文重点描述了测量仪与数控系统的接口连接、测量仪的校准、宏程序的编制.通过在线检测进一步提高了工件特殊尺寸的加工精度和产品质量.     

Automated surface subdivision and tool path generation for -axis CNC machining of sculptured parts

As an innovative and cost-effective method for carrying out multiple-axis CNC machining, -axis CNC machining technique adds an automatic indexing/rotary table with two additional discrete rotations to a regular 3-axis CNC machine, to improve its ability and efficiency for machining complex sculptured parts. In this work, a new tool path generation method to automatically subdivide a complex sculptured surface into a number of easy-to-machine surface patches; identify the favorable machining set-up/orientation for each patch; and generate effective 3-axis CNC tool paths for each patch is introduced. The method and its advantages are illustrated using an example of sculptured surface machining. The work contributes to automated multiple-axis CNC tool path generation for sculptured part machining and forms a foundation for further research.     

An advanced STEP-NC controller for intelligent machining processes

Major improvements in high speed machining technologies are not followed by suitable evolutions of the programming standard ISO 6983, also called G-code. New STEP-NC standard aims at performing high level intelligent NC programming adapted to modern machining issues. The integration of manufacturing level in the numerical chain CAD–CAM–Simulation–CNC allows the implementation of a unique file gathering of all the needed information of a part that is directly machined without post-processing. In this paper, the authors show the new possibilities in terms of the following criteria: integrating simulation and optimization of the machining parameters, providing feedback to CNC controller, allowing modifications of the geometry and machining parameters on the CNC, computing new algorithms for tool-paths generation, adaptation to machine structure and characteristics, etc. A STEP-NC interface has been developed for CNC machine tools. It enables parts machining from a STEP-NC file and integrates several new possibilities and opens the way of intelligent high level programming including the machine model and an adaptation to machining real conditions.     

基于视觉的结构变形测量系统的实现

为了测量自行车把动态加载变形量,辅助车把疲劳试验,提出了基于机器视觉的车把图像测量系统设计方法.考虑到零件表面不确定性,采用黏贴圆形标志于表面进行变形量测量,对采集的实时图像进行线性滤波等预处理,连续轮廓搜索函数搜寻待测目标,进行基于随机Hough变换的圆形标志检测,接着利用图像特征参数计算实时变形量.根据误差理论对测量结果进行数据处理与分析.实验结果表明该测量方法效果明显,测量精度可以达到0.03mm,高于常规测试方法的测试精度,能够达到车把加载变形高精度测量的要求.     

电解加工中最小间隙检测方法

针对现有间隙检测方法存在精度低,且仅能测量平均间隙的缺点,提出一种测量最小间隙的简单方法———低电压湿对刀方法,介绍了湿对刀方法测最小加工间隙的原理,并进行了试验验证,试验结果表明:测量精度可达2μm。     

Realization of STEP-NC enabled machining

A STEP-compliant CNC machine tool that demonstrated a G-code free machining scenario is presented. The aim of this research is to showcase the advantages of, and evaluate, STEP-NC—a new NC data model—by implementing it in a legacy CNC system. The work consists of two parts: retrofitting an existing CNC machine and the development of a STEP-compliant NC Converter called STEPcNC. The CompuCam's motion control system is used for retrofitting the machine, which is programmable using its own motion control language—6K Motion Control language and capable of interfacing with other CAPP/CAM programs through languages such as Visual Basic, Visual C++ and Delphi. STEPcNC can understand and process STEP-NC codes, and interface with the CNC controller through a Human Machine Interface. It makes use of STEP-NC information such as “Workplan”, “Workingstep”, machining strategy, machining features and cutting tools that is present in a STEP-NC file. Hence, the system is truly feature-based. The Application Interpreted Model of STEP-NC has been used.     

A novel methodology for cross-technology interoperability in CNC machining

In CNC part programmes, the lack of standardisation for representing part geometry and semantics of manufacturing operations leads to the necessity for existence of a unique part programme for each machine. Generating multiple programmes for producing the same part is not a value adding activity and is very time consuming. This wasteful activity can be eliminated if users are given the ability to write an NC program for a specific machine and robustly convert the program to syntax suitable for another CNC machine with a different structure. This, cross-technology interoperability, would enable for parts manufactured on old CNC machines using legacy code to be manufactured on new CNC machines by automatically converting the programmes. Every NC programme is written based on various categories of information such as: cutting tool specifications, process planning knowledge and machine tool information. This paper presents an approach for cross-technology interoperability by refining high-level process information (i.e., geometric features on the part and embedded manufacturing resource data) from NC programmes. These refined items of information stored in compliance with the ISO14649 (STEP-NC) standard may then be combined with new manufacturing resource information to generate NC code in a format that is compatible with machines based on different technologies. The authors provide a framework for this process of identification, semantic interpretation and re-integration of information. The focus of this paper is on asymmetric rotational components as the initial application area. To demonstrate the proposed cross-technology interoperability approach, a C-axis CNC turn–mill machine and a 4 axis CNC machining centre have been used with a simple test component.     

数控机床几何误差非接触圆轨迹检测方法研究

几何误差是评定数控机床精度的主要指标之一。本文提出一种基于圆测法,利用两台激光干涉仪及可控移动平台实现数控机床几何误差检测的新方法,文章介绍了该方法的基本原理,完成了测量系统的设计,并推导出单项误差分离的模型。使用该方法与球杆仪法分别在MCV-510数控加工中心上进行模拟测量,实验表明：两种方法测得数据的最大绝对误差是0.8μm,从而证明该方法的可行性和正确性。     

Design of a decision support system for machine tool selection based on machine characteristics and performance tests

Economic globalization, together with heightened market competition and increasingly short product life cycles are motivating companies to use advanced manufacturing technologies. Use of high speed machining is increasingly widespread; however, as the technology is relatively new, it lacks a deep-rooted knowledge base which would facilitate implementation. One of the most frequent problems facing companies wishing to adopt this technology is selecting the most appropriate machine tool for the product in question and own enterprise characteristics. This paper presents a decision support system for high speed milling machine tool selection based on machine characteristics and performance tests. Profile machining tests are designed and conducted in participating machining centers. The decision support system is based on product dimension accuracy, process parameters such as feed rate and interpolation scheme used by CNC and machine characteristics such as machine accuracy and cost. Experimental data for process error and cycle operation time are obtained from profile machining tests with different geometrical feature zones that are often used in manufacturing of discrete parts or die/moulds. All those input parameters have direct impact on productivity and manufacturing cost. Artificial neural network models are utilized for decision support system with reasonable prediction capability.     

Cloud-based approach for automatic CNC workpiece origin localization based on image analysis

Computer vision applications in the industry have been a constant field of research in academia. Industrial daily challenges such as quality inspection, object detection, and measurement are examples of situations where some automation could be done by using computer vision techniques. In this paper, a cloud-based approach of an automatic system based on stereo vision and image analysis has been developed to automate a daily routine present in machining companies: workpiece referencing. The proposed architecture uses two cameras mounted in the spindle of a machining center. All images are processed in custom software, running on the cloud, to return the position of the Workpiece Coordinate System (WCS) directly to the Computer Numerical Control (CNC) machine controller. Experimental results validate the application of the proposed architecture in a real machining process machine.