共查询到18条相似文献,搜索用时 265 毫秒
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基于模板的大型复杂曲面超声C扫方法 总被引:1,自引:0,他引:1
针对大型复杂曲面工件通常采用不完全定位安装,超声C扫查路径生成过程重复耗时的问题,提出了一种基于模板的扫查方法.该方法首先对第1个扫查工件表面进行采样,重构生成初始曲面模型,再通过仿形测量修正初始曲面模型,生成高精度CAD(computer aided design)模板.下一个扫描工件在合理获取少量测量点后,根据模板曲面的几何性质进行精确重定位,并利用模板快速生成该工件的扫查路径.仿真与实验结果表明,该方法可以快速地生成高精度扫查路径,大大缩短了非扫查准备时间,提高了检测效率. 相似文献
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胡建玥 《机械制造与自动化》2024,(1):196-201
为进一步提升工业机器人磨抛自由曲面时的轨迹跟踪控制技术,设计一种自由曲面磨抛轨迹自动生成方法。生成工件的STL模型,利用Bezier三角曲面拟合方法得到工件的拟合曲面,基于螺旋式磨抛轨迹实现自由曲面轨迹规划;利用等参数法和轨迹偏置的方法生成全部的轨迹,根据曲线路径曲率的变化,自适应调节控制点的间距,避免了曲线偏置时的干涉问题;在工业机器人腕处安装6D力传感器,利用力/位置混合控制方法对工业机器人进行运动轨迹跟踪控制。通过实验平台测试,验证该方法能够有效地进行曲面跟踪控制。 相似文献
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自由曲面加工中的等参数螺旋轨迹生成方法 总被引:6,自引:1,他引:5
通过对刀具轨迹有效性的分析,将刀具轨迹规划分为曲面上曲线族的选择和有效合理排布方式的设计两个方面。以此为基础,针对数控加工中心的高速加工特性,提出一种等参数螺旋刀具轨迹生成方法。该方法以减少抬刀、路径转接为目的,并综合考虑刀具轨迹几何与运动力学性能。首先以等参数线型轨迹为基础,生成等参数环形轨迹,进而以对角曲线连接相邻路径,构造能够实现连续切削的等参数螺旋轨迹。仿真试验表明该方法,简单实用,而且避免了轮廓偏置中的干涉检测,特别适用于自由曲面的高速数控加工。 相似文献
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复杂曲面工件的超声无损检测系统研制 总被引:8,自引:0,他引:8
为了实现大型复杂曲面工件的自动化缺陷检测,开发了超声无损检测机器人系统.论述了复杂曲面工件的超声检测原理、检测机器人系统模型、分布式的系统控制模式.工件检测试验表明,该系统具有较好的稳定性、可靠性,检测精度高、效率高,能达到工业生产的要求,在大型复杂曲面工件的超声检测中有良好的应用前景. 相似文献
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针对复杂曲面笔式加工时刀具路径为无具体方程表达式的特点,给出一种可保持刀触点切削速率恒定的空间曲线插补算法。该算法根据导动曲线和刀触点轨迹的加工状态近似模型,通过简化导动曲线参数的计算,间接得到投影在曲面上的曲线插补点。该算法的提出扩充了CNC系统的轨迹控制功能,提高了复杂曲面的加工效率。仿真结果证明该算法可行且有效。 相似文献
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Dr Y. N. Hu W. C. Tse Y. H. Chen Z. D. Zhou 《The International Journal of Advanced Manufacturing Technology》1998,14(5):321-329
In the manufacture of parts with sculptured cavities from prismatic stock, rough machining usually constitutes most of the machining time owing to the significant difference between the stock and the part shape. When using 2 1/2-D milling or a contour-map approach to do the rough machining, the appropriate selection of tool-path pattern for each cutting layer can significantly reduce rough machining time and hence increase productivity. In this paper, the commonly used toolpath patterns are summarised. A knowledge-based parametric approach for optimising the toolpath pattern of a given cutting layer is proposed. Then, a novel methodology is developed to calculate an arbitrary polygon area and locate the concave cavities in the polygon. Procedures for cutting-layer-shape analysis and the optimal comprehensive tool-path pattern generation are also built and proposed in this paper. These procedures can not only be applied to sculptured cavity parts with simple islands, but also to parts with arbitrarily-shaped islands. Finally, an example is given to illustrate the reasoning process. 相似文献
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Machined parts having sculptured surfaces pose challenges in the field of CAD/CAM. Sculptured surfaces are essential in the manufacture of components with curved geometry, which are demanded mostly in the aerospace and die and mould industries. This paper presents an adaptive cutter path restraining method for freeform surface machining and its implementation in milling. The ultimate goal is to achieve high contouring accuracy for sculptured parts machining which is a principal index for the performance evaluation of CNC machines. The proposed method is robust in achieving the desired surface cutting with the capability of satisfying pre-specified tolerance requirements using certain adaptive laws. The given tolerance is measured as the angular deviation by which the generated cutter path differs from the desired path. Since the feedrate is considered to be the most significant cutting parameter, only feedrate variations from 5 mm s-1 to 30 mm s -1 are applied in this system. The tool paths generated with and without the adaptive mechanism are compared. The proposed methodology has been tested on a CNC milling system with an open-architecture controller. The experimental results demonstrate that the proposed tolerance feedback mechanism is very effective for producing parts with sculptured surfaces. 相似文献
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Z. C. Wei M. J. Wang Y. J. Cai J. N. Zhu L. Wang 《The International Journal of Advanced Manufacturing Technology》2013,65(1-4):363-369
This paper presents a flexible model for estimating the form error in three-axis ball-end milling of sculptured surface with z-level contouring tool path. At an interval of feed per tooth, the whole process of sculptured surface machining is treated as a combination of sequential small inclined surface milling. For ball-end milling of the inclined surface with z-level contouring tool path, at surface generation position, an analytical model is proposed to identify the feedback effect of tool deflection on cutting edge engagement. The deflection-dependent cutting edge engagement is determined by using an iterative procedure. And ultimately, the form error is obtained from the balanced tool deflection and associated surface inclination angle. In a validation experiment, the estimated form errors are compared with both the measurements and the predictions of a rigid model. It is shown that the proposed flexible model gives significant better predictions of the form error than rigid model. Good agreement between the predicted and measured form errors is demonstrated for the ball-end milling of sculptured surface with z-level contouring tool path. 相似文献
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Manufacturability Analysis for a Sculptured Surface Using Visibility Cone Computation 总被引:3,自引:2,他引:1
W Yang H Ding Y Xiong 《The International Journal of Advanced Manufacturing Technology》1999,15(5):317-321
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. 相似文献
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基于正向杜邦指标线的五坐标侧铣加工 总被引:2,自引:0,他引:2
为实现叶轮类零件的多坐标侧铣加工,通过引入正向杜邦指标线,利用鼓锥形刀对自由曲面的五坐标侧铣加工进行研究。针对具有严格凸切削刃的侧铣加工刀具,提出不发生局部干涉的充要条件是切触点处刀具曲面的正向杜邦指标线位于被加工曲面的正向杜邦指标线之内。给出利用鼓锥形刀侧铣加工自由曲面时实施干涉检查的判断准则以及消除干涉的修正方法,推导出具有严格凸切削刃的刀具在给定的残留高度下侧铣加工带宽的计算方法。在此基础上,利用等残留高度法实现鼓锥形刀侧铣加工自由曲面无干涉刀具轨迹的生成。算例表明,在相同残留高度下,鼓锥形刀侧铣较之球头刀加工效率提高37.44%,说明侧铣加工是提高切削效率和加工质量的一种有效途径。 相似文献
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平头锥状刀五轴数控联动刀位轨迹的自动生成 总被引:1,自引:0,他引:1
基于点涉法原理和平头推状刀的特点、,推导出了在凸曲面上平头锥状刀五轴数控联动刀位轨迹的计算方法,依据该计算方法和规划好的刀具路径,可以自动生成平头银状刀五轴数控联动的刀位轨迹。 相似文献
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T. S. Lee Y. J. Lin 《The International Journal of Advanced Manufacturing Technology》1999,15(9):640-648
This paper presents an investigation of jerk continuity in milling operations for sculptured surfaces of mechanical parts.
It has been realised that chattering in machining operations can cause detrimental effects on the quality of machined parts
as well as on the life of the cutting tool. One of the major reasons of chattering is known to be the rough transition of
cutter accelerations when traversing through desired part sur-faces. The problem becomes serious when machining sculptured
surfaces of parts. In this work, an effective computer-aided sculptured surface design technique is proposed. The ultimate
goal is to achieve smooth and near chattering-free machining for producing precision parts. The proposed surface design scheme
models the part’s sculptured surfaces in such a way that it warrants a smooth "jerk" transition at the boundaries of common
surface patches on the part. This results in a drastic reduction of large step changes of cutter accelerations during machining
operations which will in turn eliminate a good portion of the chattering effects. Three theorems concerning the necessary
jerk continuity conditions for surface patches connections are developed and their proofs are presented. Examples of an aerofoil
and a concept car model are implemented, using the proposed modelling approach, to demonstrate its effectiveness. 相似文献
18.
Gerardo Salas Bolaños Sanjeev Bedi Stephen Mann 《The International Journal of Advanced Manufacturing Technology》2014,70(9-12):1813-1825
A tool path generation method for a sculptured surface defined by a triangular mesh is presented. Existing tool methods require extensive computer processing power mainly because surface topology for triangular meshes is not provided. The three-axis tool path planning method presented in this paper for generalized radius end mills avoids this problem (and does not need topological information) by offsetting each triangular facet individually. Offsetting a single triangle results in many more triangles, many of which are redundant, increasing the time required for data handling in subsequent steps. To avoid the large number of triangles, the proposed method creates a bounding space to which the offset surface is limited. Applying the boundary space limits the size of the offset surface resulting in a reduction in the number of triangular surfaces generated. The offset surface generation may still result in unwanted intersecting triangles. The tool path planning strategy addresses this issue by applying hidden-surface removal algorithms. Simulation and machining tests are used to validate the tool paths generated using this method. 相似文献