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1.
本文通过阐述CAXA在数控技术中的编程理论,详细说明了用CAXA制造工程师实现数控加工的过程,并论述了数字化制造所特有的优越性,并为数控技术中的CAXA只要工程师在数字化制造过程提供了理论依据。  相似文献   

2.
    
In this paper, we present a multipoint machining method for the 5-axis machining of triangulated surfaces with radiused end mills. The main idea is to drop the tool onto the surface to find an initial point of contact, and then rotate the tool while maintaining tangency with this initial point of contact until a second point of contact is found. The proposed procedure ensures a gouge-free position with two points of contact, allowing for a larger side step than a single point of contact method. This proof of concept paper presents the mathematical equations that must be solved to position the tool with two points of contacts on an STL surface. The paper further verifies the concept with simulations and presents experimental results to confirm the simulations.  相似文献   

3.
We describe a device which uses a neural network to generate part-programs for milling, drilling and similar operations on machining centres, on the basis of 2D, 2.5D or 3D geometric models of prismatic parts, without operator intervention. The neural network consists of networks for prediction of milling strategy, for prediction of surface quality and for the optimisation of technological parameters in milling. We introduce the surface complexity index (SCI) for identifying surfaces which are very difficult to machine. The SCI takes the surface roughness and machining strategy into account. Teaching and testing of the NN is described. The device, which can be retrofitted to a CNC controller, can be trained from a set of typical parts and will then generate new NC part-programs. A case study of a tool used in the automotive supplier industry shows how a milling strategy is proposed, according to set constraints.  相似文献   

4.
高性能运动控制在数控系统中的应用综述   总被引:5,自引:0,他引:5  
分析了在高速高精度加工中设计高性能运动控制器时存在的问题及面临的挑战,评述了高性能数控系统运动控制器设计方法的发展现状,对存在的主要问题和今后可能的发展方向作了进一步的探讨.  相似文献   

5.
The paper presents an approach for on-line path generation and interpolation for the machining of implicit surfaces. For a given implicit surface, once the cutting plane direction and cut-in points have been selected, iso-planar tool paths and interpolated points can be calculated on-line according to the feedrate and scallop height requirements. The approach enables the tool position and orientation to be correctly calculated at each interpolated point. Validation examples are provided for the interpolation of cyclide surfaces with planar and curved boundaries.  相似文献   

6.
  总被引:10,自引:0,他引:10  
Today's machining shop floors, characterized by large variety of products in small batch sizes, require dynamic control and real-time monitoring capabilities that are responsive and adaptive to the rapid changes of production capability and functionality. It is especially true when the shop floors are combined with the e-manufacturing concept. However, a highly efficient infrastructure that can integrate the pieces of automated equipment together and link them to the e-manufacturing is still missing. The objective of this research is to develop an appropriate methodology with open architecture for real-time monitoring and remote control of networked CNC machines. A framework named Wise-ShopFloor (Web-based-integrated sensor-driven e-ShopFloor) is designed for this purpose. Within the context, this paper presents a new enabling technology to bring traditional CNC machine tools on-line with combined monitoring and control capability. Issues such as architecture design, methodology development, and prototype implementation are addressed through a milling machine case study. It is expected that the developed technology can be readily applied to real shop floor environments with increased productivity, flexibility, and responsiveness.  相似文献   

7.
The ability to produce products, suited to a particular individual is becoming more prevalent in today’s society. This requires more efficient and rapid methods for manufacturing of bespoke products. One such method being currently developed is the cryogenic CNC machining of soft materials for producing personalised shoe insoles and outsoles. A major element of cryogenic CNC machining is the freezing of the soft polymers, which subsequently contract. This paper describes a method for predicting and compensating for the effect of cryogenic material contraction for the commonly used shoe midsole foamed polymer, ethylene vinyl acetate (EVA). Using the linear coefficient of thermal expansion a scaling factor for EVA has been developed to enable it to be accurately cryogenically CNC machined. This factor is then applied to the X, Y and Z scaling within the Delcam CAM software to shrink the model. The process is tested for a series of EVA cube test pieces and the results provide a scaling factor, which shows that the linear scaled dimension are within 1% of the measured contracted X, Y and Z dimensions. The scaling factor is subsequently used on an example low density EVA orthotic insole, which is cryogenically machined and then compared dimensionally with the original CAD model. It was found that using the cryogenic contraction factor the cryogenically machined insole had a dimensional X, Y, Z error of less than 1% when compared and analysed with the original CAD model.  相似文献   

8.
五轴联动数控加工中的微小程序段插补方法   总被引:2,自引:0,他引:2  
针对五轴联动数控系统在加工微小程序段时频繁启动/停止导致机床产生剧烈振动的问题,提出一种五坐标微小程序段插补方法.该方法能够对多个微小程序段进行统一加减速处理,在保证加工精度的同时,实现对微小程序段的连续加工.五轴联动数控系统上的仿真实验结果表明该方法减少了加工微小程序段时的加减速频率,提高了加工速度.  相似文献   

9.
NURBS surfaces are commonly used in CAD/CAM software systems to represent the complex shapes of mechanical parts. Well-planned tool paths for machining the surfaces can significantly increase cutting efficiency and improve part quality. The steepest ascent tool-path pattern has been proposed for making sculptured surfaces in a 3-axis finish milling operation, and it has been proven that a steepest ascent tool-path is inherently more efficient in removing material to make these surfaces within tolerances than a tool path of any other type. However, the mathematical representation of steepest ascent paths on NURBS surfaces has not been addressed. In our work, simplified formulae of these paths are derived, and a comprehensive, efficient algorithm to plan steepest ascent tool-paths on compound NURBS surfaces is developed. To verify its validity and efficiency, this innovative approach is applied to a complicated compound surface. Furthermore, a comparison between the steepest ascent and CATIA tool-paths on two NURBS surfaces is conducted to demonstrate the advantages of the steepest ascent tool-paths for NURBS surface part production.  相似文献   

10.
数控加工技术以其加工过程人工干预少、加工效率高、产品质量稳定等优点在现代航空制造业中得到了广泛应用。因航空产品更新换代快、新研发项目多等因素的影响,传统的单纯人工物流方式耗时大、速度慢、占据空间大等缺点凸显。构建该物流自动控制系统的主要目的在于对数控加工过程中的工装物流环节进行系统、科学管理,自动地实现存取、调配,进一步提高数控加工的生产效率。  相似文献   

11.
通过分析非线性误差及其对多轴数控加工的影响,提出了基于复杂曲面的多轴数控加工中非线性误差的控制方法,以期为提高多轴数控机床的加工精度贡献力量。  相似文献   

12.
面向数控系统中的应用,研究以触摸屏作为运动控制器的人机界面,实现对数控机床生产过程的直观化、简易化和有效化的操作控制.触摸屏通过Modbus协议通信实现对运动控制器的控制和监控.通过触摸屏和开放式运动控制器的软硬件联调表明,本系统的功能和性能达到了预期设计要求,实现了直观、简洁、鲜明的人机界面.  相似文献   

13.
黄华  李爱平  林献坤 《计算机应用》2007,27(7):1737-1740
在模糊控制器的设计过程中,为了使模糊控制器的性能达到全局优化,应用免疫遗传算法对模糊控制器参数进行优化设计;在综合考虑各种参数对控制器性能影响的基础上,给出了一种全面优化隶属度函数、比例因子和量化因子的优化方法;利用了免疫算法能保持个体的多样性和能对学习过程进行引导的特点,对模糊控制器的多个参数同时进行优化,从而显著提高了系统的收敛性、稳定性。应用该方法对数控铣削加工过程的模糊控制器的设计进行了仿真,并与其他方法进行比较和控制实例的验证,表明了该基于免疫遗传算法优化的模糊器能获得更优良的控制性能。  相似文献   

14.
An optimization approach for biarc curve-fitting of B-spline curves   总被引:6,自引:0,他引:6  
We present an approach to the optimal fitting of a biarc-spline to a given B-spline curve. The objective is to minimize the area between the original B-spline curve and the fitted curve. Such an objective has obvious practical implications. This approach differs from conventional biarc curve-fitting techniques in two main aspects and has some desirable features. Firstly, it exploits the inherent freedom in the choice of the biarc that can be fitted to a given pair of end-points and their tangents. The conventional approach to biarc curve-fitting introduces additional constraints, such as the minimal difference in curvature or others to uniquely determine successive biarcs. In this approach, such constraints are not imposed. Instead, the freedom is exploited in the problem formulation to achieve a better fit. Secondly, the end-points do not lie on the curve so that appropriate tolerance control can be imposed through the use of additional constraints. Almost all previous biarc-fitting methods consider end-points that are on the original curve. As a result of these two aspects, the resulting biarc curve fits closely to the original curve with relatively fewer segments. This has a desirable effect on the surface finish, verification of CNC codes and memory requirement. Numerical results of the application of this approach to several examples are presented.  相似文献   

15.
寇晓雨 《软件》2012,(5):84-85
CAXA系列软件已经具有了非常丰富的功能,其应用范围涵盖了制造业的多种领域。CAXA系列软件的应用可以有效的解决手动编程过程中需要处理的大量计算问题,从而很大程度上缩短了编程所需的时间,同时可以减少人为错误,提升了编程效率和编程质量。本文主要对CAXA软件在自动编程中几点注意问题,并就几个难点问题进行解析。  相似文献   

16.
Parametric interpolation using sampled data   总被引:1,自引:0,他引:1  
Trajectory in high-speed precision machining requires very small feed-rate fluctuation and contour error, which can be achieved with parametric interpolation. Since it is impossible to exactly compute the arc-length of a general parametric curve, the conventional parametric interpolation obtains a parameter through a real-time update. Thus it cannot be used with a preplanned feed-rate profile, which restricts its applications. To overcome such a problem, the proposed algorithm estimate parameters using tabulated parameter and length data. The simulations show the proposed method useful with smaller contour error and acceptable feed-rate fluctuation comparable to the second order real-time parametric interpolation.  相似文献   

17.
    
The digital models are the fundamental elements used in the virtual simulation of CNC machining for process planning, result prediction, analysis, etc. The essential work to build the digital models of machined parts is the calculation of the envelope surface generated by moving a cutter surface relative to workpieces. This calculation is usually complicated, and the requirements in different cases are also varied. Hence, it is very beneficial to develop an effective approach for different requirements. In this work, a comprehensive envelope approach is established, and it adaptively choose 1) the elimination parameter among two cutter surface parameters, 2) the representation form of envelope surface, and 3) the discretization way, so it is robust to satisfy different requirements. The elimination parameter and representation form are adaptively chosen to improve the calculation efficiency by obtaining the closed-form representation of the envelope surface prior to the implicit one. The discretization way is further adaptively chosen to obtain approximately even point distribution to the applications of 3D and FEA modeling. Finally, comprehensive algorithms are proposed to effectively implement this adaptive envelope approach for different applications. The examples are given to the manufacturing of spiral bevel gears and five-axis CNC milling.  相似文献   

18.
This study investigates the closed-loop measurement error in computer numerical controlled (CNC) milling as they relate to the different inspection techniques. The on-line inspection of machining accuracy using a spindle probe has an inherent shortcoming because the same machine-produced parts are used for inspection. In order to use the spindle probe measurement as a means of correcting deviations in machining, the magnitude of measurement errors needs to be quantified. The empirical verification was made by conducting three sets of cutting experiments, followed by a design of experiment with three levels and three factors on a state-of-the-art CNC machining center. Three different material types and parameter settings were selected to simulate a diverse cutting condition. During the cutting, the cutting force and spindle vibration sensor signals were collected and a tool wear was recorded using a computer vision system. The bore tolerance was gauged by a spindle probe as well as a coordinate-measuring machine. The difference between the two measurements was defined as a closed-loop measurement error and the subsequent analysis was performed to determine the significant factors affecting the errors. The analysis results showed the potential of improving production efficiency and improved part quality.  相似文献   

19.
多坐标曲面加工中进给速度的优化控制   总被引:6,自引:0,他引:6       下载免费PDF全文
介绍了基于曲面CNC(Computer Numerical Control)直接插补方式的多坐标曲面加工中进给速度的控制原理.综合考虑刀具相对零件表面切削进给速度的恒定,曲面形状引起的各运动轴速度及其变化率不超过伺服驱动能力,以及饥床在启动、停止和速度变化时的平滑加减速运动控制等因素,实现了进给速度的合理确定与控制,可有效提高曲面加工质量和加工效率.  相似文献   

20.
Curvilinear space-filling curves for five-axis machining   总被引:1,自引:0,他引:1  
The paper presents a new combination of two methods for tool path generation for five-axis machining proposed earlier by the authors. The first method is based on the grid generation technologies whereas the second method exploits the space-filling curve approach. Combination of the two techniques is superior with regard to the conventional methods and with regard to the case when the two methods are applied independently. In particular the algorithm allows us to generate tool paths for workpieces with complex boundaries as well as when the scallop and gouging constraints are changing sharply and irregularly. In this case the conventional methods are inefficient, whereas the proposed algorithms construct the required tool path and reduce the length of the path and the time of the machining. The numerical experiments are complemented by the real machining as well as by the test simulations on the Unigraphics 18.  相似文献   

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