复杂曲面叶片的数控加工技术探讨

本文介绍了叶片的数控加工工艺和加工方法,又介绍了如何解决叶片加工中刀具的干涉、过切及清根等关键性的技术问题。叶片的数控加工开始引入高职教学,可供高职学生、初学者及教师教学参考。     

马鞍形空间曲面的数控加工

本文论述了马鞍形空间曲面的数控加工原理、数学模型的建立和加工方法,为复杂空间曲面的加工提供了一种新途径,对从事数控加工的技术人员具有启发作用。     

空间自由曲面的数控精确加工

从空间自由曲面的数控加工原理出发，分析了空间自由曲面在数控加工中的理论误差以及控制误差的途径；并着重讨论了在空间自由曲面加工中由加工工艺方面引起的加工误差，提出了一些在曲面加工中必须引起重视的问题及如何利用计算机辅助技术来减小这部分误差的方法。     

数控加工技术在自由曲面加工中的应用

为提升对自由曲面零件的加工质量、精度和效率,在对五轴数控加工技术和高速数控加工技术分析的基础上,详细对五轴数控加工技术和高速数控加工技术的工艺进行研究,并以螺旋桨叶轮为例完成其加工参数的设计.     

三元叶轮数控加工技术

论述了三元叶轮多坐标数控加工技术，特别是４．５坐标及５坐标微机数控系统，多种曲线综合插补控制功能以及分段细分补偿技术，这些技术已得到成的应用。     

模具曲面数控加工

随着我国汽车工业的快速发展,与之配套的模具企业迎来了前所未有的发展机遇。但一般中小模具企业都受到交货周期短、质量要求高等问题的双重困扰,而解决这两个问题的关键就在于数控加工环节。数控加工环节时间的长短、加工工艺合理与否等问题还会影响到后期钳工装配试模的质量和周期。因此,各个企业都在努力保障加工制造环节的可控性、加工工艺的优化性。当然,所有这些对数控加工环节的要求都归结到数控编上。     

五轴数控加工叶轮轮毂曲面刀位轨迹的规划

对整体叶轮轮毂面的刀位轨迹排布进行了研究.首先运用分层的思想和旋转法得到均布于等长叶片叶轮轮毂面上的刀位轨迹;并在其基础上采用区域划分法对交错叶片叶轮轮毂曲面的刀位进行规划,得到C1连续的刀位轨迹.     

适应数控加工的空间曲面的建立

在数控加工中,对复杂形体表面加工的一个难点就是曲面方程的建立,如何对空间自由曲面建立数学模型已成热点。文中论述了适应数控加工B样条曲面建立的方法,指出了B样条曲面具有一、二阶连续的特性,可以用多个曲面片的拼接而组成任意形状的自由曲面,从而解决了数控加工中空间曲面建模的难题,为建立空间自由曲面提供了确凿的理论依据。     

分流叶轮五轴数控加工仿真优化

目前,分流叶轮的整体加工技术仍处在发展和创新阶段,其加工难点在于叶片曲面造型过于复杂以及在现有加工技术下难以保证加工效率和精度。分流叶轮的数控加工技术已用于实际生产,但仍存在很多缺陷。本文利用UG NX软件获得参数化模型及NC程序,利用VERICUT进行模拟仿真和优化程序,并运用五轴联动设备加工叶轮,克服了常规工艺的加工难点,实现了分流叶轮的高效率和高精度加工。     

Digitization modeling and CNC machining for enveloping surface parts

Nowadays, the demand for high-quality enveloping surface parts is increasing in machinery, aviation, military, and many other fields. Given the complexity of the surfaces, the enveloping surfaces parts are usually processed by grinding method. This grinding process is low in precision and poor in efficiency for lack of accurate digital CAD model of these parts. In this paper, a new modeling method for the complicated enveloping parts has been developed. The digital CAD model is constructed by using vector representation, transformation matrix, and spatial meshing theory. Next, a better computerized numerical control (CNC) machining code is generated based on the accurate digital CAD model, and a high-quality envelope surface could be machined on the basis of the code in CNC machining center. The normal vector algorithm is adopted to detect and avoid collision and interference during the processing. Finally, the digital CAD models of a planar double-enveloping worm and worm wheel famous at difficulty in modeling and CNC machining have been conducted as an instance. The machining experiment results show that the machining precision of the enveloping surface parts have been increased because the part’s digital CAD model is extraordinarily accurate.     

A real-time surface interpolator methodology for precision CNC machining of swept surfaces

A real-time surface interpolator is developed to machine a family of swept surfaces directly from their high-level procedural definitions. All the computations required for machining are performed in real time based on the exact surface geometry, including tool path planning, tool path interpolation, tool offsetting, and tool path step-over to achieve a prescribed scallop height. A G-code command (G05) is introduced to concisely communicate the precise surface geometry and all necessary process parameters to the controller. The swept surface interpolator offers profound accuracy and efficiency advantages over the traditional approach of generating voluminous piecewise–linear/circular tool path approximations as a preprocessing step. For example, in one instance, a 36,000-line piecewise-linear (G01) approximate part program file is replaced by a 3-line exact swept surface (G05) part program file. The methodology is verified by machining a variety of swept surface forms in aluminum and wax, using a 3-axis milling machine with the surface interpolator incorporated into an open-architecture CNC controller.     

Complexity analysis and calculation for sculptured surface in multi-axis CNC machining based on surface subdivision

Complexity of sculptured surfaces has a great influence on multi-axis computer numerical control (CNC) machining performances such as processing efficiency, surface quality, and energy consumption. A term called surface machining complexity (SMC) is first presented to describe the complexity level of surface geometrical shape features, and its influence on CNC machining performance. Shape features of sculptured surfaces are classified into seven categories based on surface curvature. An innovative method for quantifying SMC using surface subdivision is proposed. Firstly, representation of sculptured surfaces is introduced. Then, three processes of surface subdivision are presented, which are surface discretization based on iso-parameter line sampling, rough partitioning based on surface shape categories, and region grouping based on two criteria. After that calculation, formulas of SMC including formulas of local SMC and global SMC are developed. The proposed formulas utilize three correction factors to describe the influences of surface size, cutter diameter, grouping order, and mode of different surface shape categories. Finally, the proposed method is applied to calculate SMC for a typical sculptured surface and multi-axis CNC machining experiments to demonstrate the ability of our method, which can form a foundation for further research.     

Simulation model for CNC machining of sculptured surface allowing different levels of detail

Recently, CNC machining simulations require exponentially increasing computational time and memories of the computers, which have become a significant challenge for both computer hardware and software. This paper presents a novel geometric model for CNC machining simulations, which is called Level of details based on G-Code, or G-LODs for short. The G-LODs uses a type of progressive mesh to construct the surface simulation grid (SSG). The SSG can be adopted to simulate the CNC machining processes at proper level of details. So theoretically simulations based on the G-LODs will not excessively occupy the computational and storage resources of computers. Based on the SSG, the G-buffer method is used to construct the solid model of the parts. The methodology of how to construct the G-LODs is established. In conclusion, several simulation examples based the G-LODs are presented.     

数控加工程序的编译预处理

对数控车削加工程序校验模块的设计过程和方法进行了介绍,该软件是以VisualBasic6.0为开发平台,具有良好的人机界面,能为数控学习人员提供非常好的学习环境,重点介绍了系统组成、数控加工程序的特点、词法和语法分析等,并介绍了有关程序设计的过程,整个系统运行可靠,达到预期的设计要求。     

飞机结构零件数控加工技术研讨

随着我国航空制造技术的发展，对飞机结构零件的加工要求越来越高，尤其是对于零件的表面质量、深腔和薄壁形状以及零件的加工精度都提出了更高的要求。目前欧美许多发达国家按照高精度、高效率、高柔性的制造发展方向，已开始普遍使用高速铣削机床，并针对飞机结构零件的特点进行了大量的工艺技术研究。另外通过对难加工材料的加工工艺方法进行研究，大大提高了以钛合金为代表的难加工材料的加工效率，使飞机结构零件的数控加工不再成为制约整个飞机研制和生产的“瓶颈”。     

密接式车钩前端车钩体数控加工工艺

密接式车钩前端车钩体为典型复杂零件,研究其数控加工工艺,进一步明确编制加工工艺流程、设计合适的加工中心夹具、正确选择数控刀具和设定最佳切削工艺参数是保证钩体加工质量、提高生产效率的重要途径。     

数控插齿机加工误差探讨

重点介绍数控插齿机加工误差产生的原因现象,分析误差产生的原因,采取适当措施,减小数控插齿机的加工误差,提高数控插齿机的加工精度,以便为后期的技术攻关指明方向。     

锥形螺旋面数控加工的研究

通过对曲面数控加工运动的研究,指出曲面上的曲线也存在着活动的特征标识这一特性,提出了模仿特征标识沿曲面曲线运动的加工法.并以锥形等螺旋角刀槽作为加工实例,应用特征加工法使程序得到最大限度的简化,而且大大地提高编程效率,对一些类似零件的数控加工提供有益的参考依据.     

变导程螺纹数控车床的车削

介绍变导程螺纹的数控车床加工方法,以及在数控车床加工中的具体调整,为生产中解决变导程螺纹的加工提供参考。