数控车仿形循环指令退刀距离选择方法

通过对数控车仿形粗车循环指令G73的分析,找出刀具进给路线的规律,并从减短刀具进给路径、避免产生过切等方面考虑提出了退刀距离、精加工余量等参数的选择方法。     

提高数控仿形精度的控制方法

分析了数控仿形运动的基本特征以及影响仿形加工稳定性和精度的主要因素,提出了两种实用的控制方法。实验证明,此两种控制方法有效地提高了数控仿形加工的稳定性和精度,同时也提高了数控仿形加工的效率。     

高速切削技术在数控仿形铣床上的应用

简述了数控仿形铣床基本功能及构成,指出了高速切削技术在数控仿形铣床产品中的应用是数控铣床的必然发展趋势。     

仿形靠模数控加工自动编程软件的开发

论述了基于AutoCAD软件平台仿形磨边机中仿形靠模的数控加工编程的设计问题.首先说明了仿形靠模的数控编程原理;然后介绍了仿形靠模自动编程的功能;最后详细阐述了仿形靠模自动编程的程序结构.试验应用结果表明,此设计系统可以正确地生成ISO标准代码的数控加工程序文件,文件中的数据可直接传递到数控系统中进行加工.自动编程的设计对提高仿形靠模的加工效率和加工精度具有重大的意义.     

激光测头数控仿形跟踪控制算法

分析了曲面数控仿形加工的关键技术,针对基于激光非接触测量的数控仿形加工,提出一种测头速度控制算法,解决了复杂曲面高速、高精度仿形测量与加工的问题。     

液压仿形车床的数控化改造

介绍了液压仿形车床伺服系统的基本工作原理,给出了用步进电动机数控装置和交流伺服电动机数控装置,进行液压仿形车床的数控化改造的两种方案.     

两坐标数控立铣削的过切现象及控制

在两坐标数控铣削中,过切是常见的异常加工现象,严重地影响了加工质量.通过系统性分析,将两坐标数控立铣削的主要过切种类归为工艺系统引起的过切、数控系统功能引起的过切、工艺安排及编程引起的过切三个大类,比较系统地分析了各种过切产生的主要原因,同时提出了控制过切的措施,对避免数控立铣削过切具有一定的参考意义.     

数控仿形测量的密集散乱数据的曲面重建方法研究

数字化仿形技术是加工自由曲面的一种有效方法，而快速准确地重建数控仿形测量得到的散乱数据是实现数控仿形加工的关键步骤之一。分析了数控仿形测量数据的特点，确定重建曲面采用规则四边形网格几何结构，并提出了一种基于距离加权模型的节点插值方法，实现了散乱数据群的曲面重建。最后提供的曲面重建实例和加工实例证实了该方法是可行的。     

电液仿形铣床的数控化改造

阐述了仿形加工的基本原理及系统构成以及牧野ＤＡＵ－１５０型电液仿形铣床的数控化改造方案与实施步骤。改造后的仿形铣床界面清晰,仿形精度和速度明显提高,获得显著的经济效益     

数控仿形加工技术研究

数控仿形系统集自动控制、微电子、电子计算机、传感器、精度机械等技术于一体，是20世纪80年代国际上高效益、高技术的机电一体化产品。国外公司竞相开发了多种数控仿形系统，如日本牧野、英国雷尼绍、美国辛辛那提等公司。国内一些厂家和研究机构，如武汉华中数控股份有限公司、青海机床厂、北京第四机床厂、北京机床研究所等，也在开发生产数控仿形系统。     

Analysis and predictive modeling of performance parameters in electrochemical drilling process

In this paper, the effect of feed rate, voltage, and flow rate of electrolyte on some performance parameters such as surface roughness, material removal rate, and over-cut of SAE-XEV-F valve-steel during electrochemical drilling in NaCl and NaNo₃ electrolytic solutions have been studied using the main effect plot, the interaction plot and the ANOVA analysis. In continuation, in this case which the training dataset was small, an investigation has been done on the capability of the optimum presented regression analysis (RA), artificial neural network (ANN), and co-active neuro-fuzzy inference system (CANFIS) to predict the surface roughness, material removal rate and over-cut. The predicted parameters by the employed models have been compared with the experimental data. The comparison of results indicated that in electrochemical drilling using different electrolytic solutions, CANFIS gives the best results to predict the surface roughness and over-cut as well, while ANN is the best for predicting the material removal rate.     

基于曲率加权累加的动态速度前瞻控制

针对在高速加工、快速检测等高速进给条件下,传统速度控制方法容易导致工件过切、机床抖动等问题,提出了基于离散衔接点曲率加权累加的速度前瞻程序段数动态选择的方法。首先,分析了基于5次样条曲线拟合离散衔接点方法,然后推导了到各衔接点的曲率表达式,最后根据各点曲率加权累加值进行动态速度前瞻程序段控制,并进行了仿真验证。仿真结果表明,动态速度前瞻避免了前瞻路径过短不能完成减速要求和前瞻段数过多占用系统资源,一定程度上解决了速度和精度的冲突问题,提高了系统的性能和加工效率。     

Selective Segmentation of the Shallow Electrical Profiling Data

A method for selective segmentation that correctly recovers the boundaries of objects in the plan and estimates the depth range is proposed. This method requires that the electrical exploration data are processed: shallow electrical profiling and vector images of the main directions of changes in the resistance of the medium. An object boundary is estimated on the basis of a fuzzy clustering algorithm (fuzzy c-means), adapted for analyzing multispacing electrical profiling. The depth range of an object in soil is estimated on the basis of applying a scalar product function to vector images of the main directions, adjacent in depth. The effectiveness of this method is confirmed by computer simulation and an example of data processing of the field experiment on an archeological site, which is a medieval fortified settlement.     

整体叶轮数控加工研究

五轴数控机床加工是叶轮的一种高效率高精度生产制造方式。文章研究了整体叶轮五轴加工工艺参数设置方法,并以UGNX为数控编程软件工具,用PostBuilder创建五轴后处理程序;加工编程时采用了插补的刀轴控制方式,有效避免了干涉和过切;在VisualC＋＋开发环境下运用OpenGL开发了五轴G代码仿真软件,能够检验出通用G代码仿真软件难以发现的错误;在本实验室自主研发的五轴联动数控机床上成功加工出高精度的整体双扭叶轮。     

曲面数控仿型系统的研究与实现

在华中Ⅰ型数控系统上开发了曲面数控仿型系统,分析了数控仿型系统的硬件和软件体系结构,讨论了其中的关键技术,实现了仿型加工实时多任务控制,并针对仿型加工中的测头跟随控制问题,介绍速度圆矢量分解的算法。     

Multipatched B-Spline Surfaces and Automatic Rough Cut Path Generation

A method is proposed to generate rough cut machining tool paths for multipatched B-spline surfaces. For a group of B-spline surfaces, smoothly connected, separated or intersecting one another, this method can guarantee generating paths without overcutting any of the surfaces under consideration. The use of multipatched surfaces to construct complex surfaces can greatly increase the controllability and friendliness in the design of surfaces. A method for rough cut planning by convex hull boxing is proposed to generate paths guaranteeing no over-cut. Since no computation for solving nonlinear equation is involved, the rough cut plan is robust and efficient.     

Development of a real-time laser-based machine vision system to monitor and control welding processes

In this study, a laser-based machine vision system is developed and implemented to monitor and control welding processes. The system consists of three main modules: a laser-based vision sensor module, an image processing module, and a multi-axis motion control module. The laser-based vision sensor is designed and fabricated based on the principle of laser triangulation. By developing and implementing a new image processing algorithm on the platform of LabVIEW, the image processing module is capable of processing the images captured by the vision sensor, identifying the different types of weld joints, and detecting the feature points. Based on the detected feature points, the position information and geometrical features of the weld joint such as its depth, width, plates mismatch, and cross-sectional area can be obtained and monitored in real time. Meanwhile, by feeding these data into the multi-axis motion control module, a non-contact seam tracking is achieved by adaptively adjusting the position of the welding torch with respect to the depth and width variations of the weld joint. A 3D profile of the weld joint is also obtained in real time for the purposes of in-process weld joint monitoring and post-weld quality inspection. The results indicate that the developed laser-based machine vision system can be well suited for the measurement of weld joint geometrical features, seam tracking, and 3D profiling.     

线结构激光仿型测量中的视觉跟踪算法

分析国内现有线结构激光测量系统的特点,提出一各地ＣＮＣ系统的线结构激光仿型测量的视觉跟踪算法;该算法给出了一套较为完整的跟踪策略,解决了超视距和成像则头的自适应调节问题。     

A study on helical surface generated by the primary peripheral surfaces of ring tool

Often in the engineering practice, cutting tools bounded by primary peripheral surfaces of revolution are used because of their effectiveness. Among these, ring and tangential tools can be used for the generation of constant pitch cylindrical helical surfaces. In this paper, we present an algorithm for the profiling of these types of tools. The algorithm is based on the topological representation of the tool’s primary peripheral surface. The main goal is to devise a methodology for the profiling of tools whose surfaces are reciprocally enveloping with cylindrical helical surfaces. We present a numerical example for the numerical determination of the axial section form for this type of tools. The application method for this algorithm was developed in the CATIA graphical design environment within which the procedure is developed as a vertical application. In addition, we present a solution for the shape correction of the tool’s axial cross-section by considering the existence of singular points on the profile of the helical surface to be generated where multiple normals to the surface exist.     

An Enhanced Force Model for Sculptured Surface Machining

The ball-end milling process is used extensively in machining of sculpture surfaces in automotive, die/mold, and aerospace industries. In planning machining operations, the process planner has to be conservative when selecting machining conditions with respect to metal removal rate in order to avoid cutter chipping and breakage, or over-cut due to excessive cutter deflection. These problems are particularly important for machining of sculptured surfaces where axial and radial depths of cut are abruptly changing. This article presents a mathematical model that is developed to predict the cutting forces during ball-end milling of sculpture surfaces. The model has the ability to calculate the workpiece/cutter intersection domain automatically for a given cutter path, cutter, and workpiece geometries. In addition to predicting the cutting forces, the model determines the surface topography that can be visualized in solid form. Extensive experiments are performed to validate the theoretical model with measured forces. For complex part geometries, the mathematical model predictions were compared with experimental measurements.