曲面的可视方向信息计算

为了支持并行设计与制造,研究曲面可视方向信息的咨询方法。提出从曲面的几何数据中提取和分析可视方向信息,建立计算曲面可视方向的算法,并给出计算结果。借助于该方法,能够在设计阶段有效地获取一制造相关的方向信息,实现对设计的可制造性分析。     

基于计算制造技术的复杂曲面加工

阐述计算制造技术的理论基础和方法,分析影响曲面磨削的因素,针对复杂曲面磨削过程特点,研究如何从复杂曲面设计中提取几何约束的加工信息,并预处理加工零件的几何信息,以支持曲面加工的工艺规划。目的是使磨削过程中的一些问题归结为计算机可形式化描述的计算模型,研究其可计算性和复杂性,解决磨削过程中出现的几何和特征建模、磨削控制系统中知识的进化计算等问题。为复杂曲面的精密加工寻找新的途径。     

复杂曲面计算制造技术的研究

阐述了计算制造技术的理论基础和方法，分析了影响曲面磨削的种种因素，针对复杂曲面磨削过程的特点，研究如何从复杂曲面设计中提取几何约束的加工信息，并预处理加工零件的几何信息，以支持曲面加工的工艺规划活动。     

钣金冲模集成制造系统的产品信息建模

计算机集成制造是模具生产集成化和智能化的最高体现,建立钣金冲模产品信息模型是实现模具集成制造的基础。本文针对钣金冲模集成制造的功能模块,建立系统的功能模型,并给出结构化分析的 Ｉ Ｄ Ｂ Ｆ０ 图形表达;分解模具集成产品模型为制件模型、制件展开分析模型、工步设计模型、模具设计模型、零件设计模型、数控加工模型和模具装配仿真模型等,并用 Ｅ Ｘ Ｐ Ｒ Ｅ Ｓ Ｓ语言建立信息模型。     

螺旋面的变通加工方法及CAD展开计算

薄板管道类零件的应用相当普遍,其加工制造方法和相应的展开计算也已相当成熟,尤其是展开计算方面,计算机自动展开软件的应用使得原先管道加工中的难点———零件展开计算变得轻松而高效。但是,管道类零件的加工制造过程中也存在一定的难点,尤其是在中厚板零件的加工中,对于非可展曲面,由于受设备、模具等方面的影响,一直无法进行精确的计算与加工,以至于需要反复修改验证,才能获得较好的效果。一、加工实例1·零件分析我公司承接某加工制造任务时,其中直角方口变径管道共出现了4种,典型的零件如图1所示。图188°方口变径管道图该零件上口为…     

基于工艺知识库的面向制造设计系统的研究

面向制造的设计是实现并行设计的关键技术。这里以零件的机械加工为例,研究了零件模型的建立,工艺知识的表示和组织,可制造性的分析和评价等关键技术,在CAD软件的平台上开发了基于工艺知识库的面向制造的原型设计系统,并通过基于知识的可制造性分析保证所设计零件的工艺性。     

基于制造资源的复杂箱体零件可制造性评价

在复杂箱体零件设计阶段,为实现基于制造资源的箱体零件可制造性评价,首先构建一定环境下的制造资源模型。然后利用箱体零件模型信息与制造资源模型信息之间的关系建立零件评价规则。最后以零件制造特征为桥梁,判断该零件整体可制造性以及在各道工序中的可制造性,筛选出符合要求的加工设备。基于层次分析法理论构建设备优选算法,择优选择候选加工设备,辅助箱体零件工艺设计。     

基于加工特征和制造资源约束的CAD/CAPP研究

针对齿轮箱类零件的快速设计与制造,建立了制造资源管理模块,通过加工能力约束文件将制造资源与可加工特征类型及范围对应起来,设计开发了基于加工特征建模的CAD模块和基于制造资源约束的CAPP模块。基于加工特征的建模方式使得CAD与CAPP得以无缝集成,而加工能力约束文件则为CAD/CAPP集成系统提供了实时反映底层制造能力的结构设计和工艺设计约束,从而保证了设计和工艺的可制造性。     

CAXA实现模具曲面造型和三轴加工

在进行具有复杂曲面的模具设计中,采用曲面造型的方法较实体造型既简单又快捷,而且占用计算机资源少,整个设计速度将会大大提高。模具的设计和数控加工程序的生成,必须以CAD／CAM一体化软件为工作平台。下面介绍以CAXA制造工程师2004为设计和制造平台,去完成一个玩具小汽车上凸摸的设计和数控加工程序的自动生成,并将程序传到数控铣床进行加工。     

基于实例检索的回转体零件CAPP方法研究

在以特征为基础的零件信息表达基础上,将加工方法与之结合,提出了实现工艺重用的面向制造工艺的特征信息模型,使面向制造工艺的特征成为工艺设计的基本模块;并与实例推理相结合,提出了回转类零件的实例相似度算法,并以目前比较流行的CAD/CAE/CAM软件之一Unigraphics为开发平台,在VC++6.0的编译条件下,利用Unigraphics提供的二次开发工具建立零件信息输入系统,搜索零件实例库中相似信息模型,从而较好地解决了回转体零件相似工艺实例检索的问题.通过实例证明,采用该方法对回转体零件进行工艺设计,可大大提高工作效率.     

Manufacturability Analysis for a Sculptured Surface Using Visibility Cone Computation

This paper presents a general algorithm to obtain a feasible tool-approach direction for sculptured surface machining based on convex analysis. The visibility cone which represents the aggregate of all visible directions is constructed to describe geometric constraints. Combined with the convex hull computation algorithm, a detailed procedure for computing the visibility cone has been developed. The visibility cone can be used as an effective tool for manufacturability analysis of the sculptured surface when applied to CNC machining tool-path planning. After the visibility cone is acquired, tool orientation can be adjusted to adapt itself to the local geometry of the sculptured surface at each cut contact position. The proposed methodology can be applied to computer-aided planning and programming of cutter-path generation for 5-axis sculptured-surface machining.     

A concurrent manufacturing strategy for One-of-a-Kind Products with complicated sculptured surfaces

In this paper, we propose a computer-aided system for concurrently designing and manufacturing a customised or One-of-Kind Production (OKP) mould or die which has complicated sculptured surfaces. Considering the OKP production characteristics of high customisation and concurrent product development and production, we believe that the concurrent consideration of both the design and the manufacturability of a mould or a die would be necessary. This concurrence can be realised by providing timely manufacturability information feedback after a design is completed or a feature is modified or added in the design. The other problem is that the sculptured surface geometry model of a mould or a die does not contain any machining information. Hence we developed an intermediate data model for capturing manufacturing features when we are modelling the geometric form of a mould or a die. The system is based on CADDS5 which is a commercial CAD/CAM system. Two modules for data extraction, coverting and modelling as well as for manufacturability analysis have been developed and added to CADDS5. Using this computer-aided system; a designer can interrogate geometry and machining constraint information through a user friendly interface to avoid defects and inefficiency resulting from an earlier design, and can finalise the design by making quick incremental adjustments. The system has been implemented in a mould and die manufacturing company in China. This implementation leads to less rework and shorter lead time.     

Using rotary contact method for 5-axis convex sculptured surfaces machining

The 5-axis tool positioning strategy named rotary contact method (RCM) for sculptured surfaces machining has been developed in our previous paper (Wengang Fan et al., J Manuf Sci E-T ASME 134(2):021004.1-021004.6, 2012). The RCM finds the optimal tool positions by rotating the tool backward based on the offset surface instead of the design surface, and can generate big machined strip width without gouging. However, the RCM only deals with concave sculptured surfaces machining well at present, and the special property of convex sculptured surfaces machining has not been fully exploited. To resolve this problem, the general convex sculptured surfaces machining using the RCM is implemented in this paper. Firstly, the tool position error distribution for different tool feed directions is deeply investigated. It is concluded that the best tool feed direction is collinear with the maximum direction of curvature, which is completely opposite to the case for concave sculptured surfaces machining. Then the relationship between the key parameters in the RCM and the tool position error distribution as well as the tool path generation is totally discussed. Finally, machining simulation and cutting experiment of a convex sculptured surface example are performed. The results show that the RCM can apparently raise the efficiency of manufacturing process by contrast with the algorithm in the software UG for convex sculptured surfaces machining.     

Local interference detection and avoidance in five-axis NC machining of sculptured surfaces

The tool interference problem is the most critical problem faced in sculptured surface machining. This paper presents a methodology for interference detection and avoidance in five-axis NC machining of sculptured surfaces with a filleted-end cutter. The surfaces to be machined are divided into convex and non-convex regions. There is no local interference inside the convex regions. For the non-convex regions, based on the analysis of the different local interference, local gouging is first detected and avoided by determining optimal cutter orientations. Rear gouging detection and avoidance algorithms are then proposed for simple smooth surfaces and complex shaped surfaces, respectively. The techniques presented in this paper can be used to generate interference-free tool paths. The realistic results indicate that the proposed method is feasible and reliable .     

并行工程下基于特征的零件可制造性研究

结合并行工程的思想，对零件可制造性进行较详细的分析，提出并行工程环境下基于特征的可制造性分析方法，研究并建立基于特征的可制造性零件定义模型及评价体系，全面合理地对零件的可制造性进行评价和反馈，从而指导产品设计。最后以涡轮叶片榫头特征的可制造性分析为应用实例，说明该方法的有效性和实用性。     

概念结构设计过程中功能表面重构技术研究

在基于功能表面分解重构原理的生长型设计过程中，产品概念结构中功能表面的重构即功能表面的类型、数量及其相互炎系的选择与确定直接决定了零件的概念结构，并且从概念上基本确定了后续结构能否经济制造的空间约束。由于相关知识支持技术的缺乏，仍需要设计人员靠经验决定，降低了生长型设计的效率。文章分析了功能表面间的位置关系、联接方式的含义及其可制造性评价，与实际工艺技术知识相联系，提出了功能表面之间空间位置关系和联接方式的并行确定方法，开发了基于知识的设计支持模块，促进概念结构生长式设计效率的进一步提高。     

Assessment of sculptured surface milling strategies using design of experiments

Product manufacturing on CNC milling machine tools involves a number of machining parameters and tool geometries. In the case of sculptured or free-form surfaces the number of these parameters can be significantly large and vary according to surface complexity. Minimising the number of parameters is carried out through statistical elimination. Design of experiments (DoE) along with the respective statistical analysis of variance (ANOVA) constitutes a low-cost useful tool in determining sub-optimum values for all parameters involved in each milling strategy as well as the most significant of those parameters. DoE was implemented for a particular sculptured surface assessing a variety of roughing and finishing strategies of a CAM simulation software.     

振动辅助铣削加工仿生表面研究

为探究沿进给方向施加振动辅助铣削加工仿生表面形貌的可行性,通过数学计算获得了刀具与工件分离的条件。设计了仿真分析方案,将振动辅助铣削MATLAB仿真刀尖轨迹与实验加工表面以及典型生物表面形貌进行了对比分析。分析结果表明,振动辅助铣削表面形貌和典型生物表面形貌具有相似性,证明了振动辅助铣削加工技术在仿生表面加工领域应用的可行性。