Towards High-Fidelity Machining Simulation

The main purpose of any machining simulation system is to reveal or mimic the real machining process as accurately as possible. Current simulation systems often use G-code or CL data as input that has inherent drawbacks such as vendor-specific nature, incomplete data, irreversible data conversions and lack of accuracy. These limitations hinder the development of a truthful simulation system. Hence, there is a need for higher-level input data that can assist with accurate simulation for machining processes. In addition, there is also a need to take into account of true behaviour and real-time data of a machine tool. The paper presents a High-Fidelity Machining Simulation solution for more accurate results. STEP-NC is used as the input data as it provides a more complete data model for machining simulations. The status-quo of the machine tool is captured by means of sensors to provide true data values for machining simulation purposes. The outcome of the research provides a smart and better informed simulation environment. The paper reviewed some of the current simulation approaches, highlighted the current simulation problems, discussed input data sources for smart machining simulation and introduced the high-fidelity simulation system architecture.     

基于STEP-NC的CAM/CNC系统数据接口的研究

为了解决STEP-NC文件到数控加工过程中CAM与CNC系统之间互动差的问题和一些关键技术,对基于STEP-NC嵌入式CAM/CNC系统接口展开研究.在文件被输入该系统之前,通过该接口将文件数据格式转换为链表结构输入,利用链表良好的操作性为后续的信息提取、刀具路径规划等CAM功能的实施打下良好的基础,并改善系统内部各功能模块的交互能力和效率.链表的添加删减功能使现场的操作者也完全可以根据现场的条件和实际经验知识对程序内容(如工序内的工步安排和走刀路线、刀具、切削用量等)做出实时的修改,并将修改后的数控程序反馈给上游的设计部门.并介绍国际上为实现智能化数控系统而研究出的CAD/CAM/CNC集成方案.     

基于STEP-NC的零件可加工性评价指标体系研究

为了实现基于STEP-NC的零件加工程序可加工性评价,提出了一种面向STEP-NC的数控加工零件可加工性评价指标体系。在建立机床资源信息模型的基础上,分别以零件装夹性、机床性能、刀具资源、辅助功能等四个方面对零件在特定机床上的可加工性进行评价。使用Visual C#平台开发了零件可加工性评价系统,实现了STEP-NC信息提取及可加工性评价算法。     

基于ISO14649标准的STEP-NC程序生成器

为实现STEP-NC程序的自动生成,开发了STEP-NC程序生成器.首先阐述了程序生成器的工作原理和各个模块的功能及其实现方法.详细论述了程序生成器实现中的三项关键技术.最后,结合一个包含平面、孔和型腔特征的AP203文件,利用所开发的程序生成器生成符合ISO14649标准的完整的STEP-NC程序,并通过STEP-NC铣削仿真系统对所生成的程序进行切削仿真.仿真结果表明,所开发的STEP-NC程序生成器是可行的.     

A multi-agent-based intelligent STEP-NC controller for CNC machine tools

ISO 6983 has now been considered as a bottleneck for developing next generation CNC machine tools. STEP-NC is a new interface standard between CAD/CAM systems and CNC machines, which not only provides an object-oriented data model for CNC with a detailed and structured data interface that incorporates feature-based programming, but also represents a data model for intelligent computer numerical controllers. This paper presents a conceptual framework of holonic compliant data interference for numerical control STEP-NC controller to implement intelligent control for Computer Numerical Control (CNC) machine tools. The architecture is comprised of 14 functional agents, such as interpreter agent, process planning agent, NCK/PLC agent, decision-making agent, etc. These agents can co-operate closely to carry out various functions of the intelligent STEP-NC controller in a desired manner. The process flow for the STEP-NC controller is analysed. Furthermore, the implementation for two functional agents (i.e. interpreter agent and process planning agent) is described in detail. Finally, the preliminary development of a prototype system is discussed. As a result, the framework and implementation methods proposed provide a paradigm for future implementation of an intelligent STEP-NC controller.     

CNC控制器的发展趋势

数控机床是现代加工车间最重要的装备。本文概述数控机床控制器的发展趋势。随着信息技术(IT)和制造技术(MT)的发展，出现了更多功能、更高性能的控制器，诸如多坐标、多系统(通道)的控制；具有高精、高速、5轴加工功能和复杂加工、数控复合机床、进网通信、高可靠性和安全性等功能。为了增加操作和使用系统的可操作性和可移植性，控制器开放已经成为潮流。数字制造要求数控系统建立在一个全新的信息技术基础结构之上，容易利用网络传递加工制造信息，进行CAD／CAM与CNC一体化的加工制造。这就出现了STEP-NC新型的数控系统。     

基于STEP-NC的NURBS曲线插补技术研究

文章详细讨论了旧的数控编程接口标准ISO6983的缺点,研究了基于新数控编程接口标准STEP-NC的数控系统中的NURBS插补技术.详细讨论了NURBS插补算法,并进行了误差分析.STEP-NC数控系统能够直接处理由NURBS表示的几何信息和加工工艺信息,通过采用STEP-NC新数控编程接口,确保零件的NURBS曲线曲面几何信息和加工信息完整的输入到数控系统.NURBS插补程序量少,速度快,精度高,有利于提高生产率和改善产品质量.NURBS插补技术的研究为进一步研究STEP-NC数控系统奠定了基础.     

基于STEP-NC的CNC集成技术研究

目的提供描述产品整个生命周期信息的统一数据模型,实现整个制造过程中产品信息的标准化,解决实现基于STEP-NC的CNC（计算机数字控制）制造技术集成问题.方法分析了STEP-NC的数据模型和程序结构,给出了STEP-NC程序文件的基本结构和STEPAP238文件的生成方法.结果生成符合STEP-NC的数控加工程序（AP238文件）,从零件的几何模型（由CAD系统输出）中识别出需进行机械加工的制造特征.采用UG软件,实现了零件的设计、工艺规划和生成STEP-NC文件一体化,即实现了CAD/CAM的集成.结论STEP-NC程序在统一的数据模型基础上建立产品信息,保证了数据信息的集成和共享,促进了数控技术智能化、网络化和集成化的发展.     

网络化加工系统中XML语言转换的若干问题

目的 研究基于STEP-NC的网络化加工系统功能模型和STEP-NC数控程序向XML文件的转换方法 ,实现产品信息的网上传输,解决企业间产品资源共享的问题.方法 在Visual Studio.net软件环境下,采用Internet/Intranet技术和Browser/Server模式对STEP-NC网络化加工系统体系结构进行设计,分析EXPRESS与XML的映射关系建立的XML Schema映射规范库,利用配置语言完成数控程序向XML文件的转换.结果 构建了以PC机和DSP运动控制器为开发平台的网络化加工系统基本框架,根据XML Schema映射规范库实现了STEP-NC数控程序向XML文件的转换.结论 基于STEP-NC的网络化加工系统利用配置语言的新方法 完成了STEP-NC数控程序向XML文件的转换,以XML发布产品信息的形式有效地解决了异构系统之间数据交换和共享的关键问题,为网络化制造中设计、制造信息的真正集成提供了一种新的途径.     

Modelling and implementing circular sawblade stone cutting processes in STEP-NC

The paper presents a STEP-NC compliant implementation of circular sawblade stone cutting machining processes. Although some stone machining processes has been already covered in the STEP-NC research and standardization initiatives (as for instance stone machining through stone milling machines), there have not been yet, however, any detailed model proposal to cover circular sawblade stone cutting operations. Sawblade cutting technology for stone parts have several specific parameters with no clear equivalent technologies as defined in milling, turning, etc. The paper reviews main characteristics of the circular sawblade stone cutting machining operations, and proposes a STEP-NC extended model based on the selection and definition of new features and on the modelling of these stone cutting operations. The resulting model is the base for the development of the STEP-NC stone cutting CAM and CNC machine. The machine architecture is designed to be able to react to changes in the machining conditions, very common in this technology. The system is based on the definition of features to be communicated to the controller. The controller has the objective of machining the features, and it is able to re planning, on real time, the work to get them despite changing conditions in the stone or in the disc.