Efficient NC Tool Path Planning Based on the Subdivision of Sculptured Surface

2014 ◽  
Vol 635-637 ◽  
pp. 497-501
Author(s):  
Li Min ◽  
Biao Bai ◽  
Yu Hou Wu ◽  
De Hong Zhao

In this paper, we have presented a method to generate efficient NC tool paths based on the surface subdivision. The main objective is to achieve high efficiency in the machining of sculptured surface. The NC machining efficiency can be improved by segmenting the whole surface into distinct areas according to the characters of sculptured surface and by using different size mills and different tool path planning methods to machine the areas. The iso-parametric method and large mills are used in the curvature changing little areas. While the iso-scallop method and small mills are used in curvatures changing large areas. This can make full use of tool path generation methods and mills, which improve the machining efficiency of sculpture effectively.

2004 ◽  
Vol 126 (3) ◽  
pp. 515-523 ◽  
Author(s):  
Zezhong C. Chen ◽  
Geoffrey W. Vickers ◽  
Zuomin Dong

Three-axis CNC milling is often used to machine sculptured parts. Due to the complex surface shape of these parts, well-planned tool paths can significantly increase the machining efficiency. In this work a new principle of CNC tool path planning for 3-axis sculptured surface machining is proposed. Generic formula to calculate the steepest tangent direction of a sculptured surface is derived, and the algorithm of the steepest-ascending tool path generation is introduced. A single steepest-ascending tool path has been verified to be more efficient than a single tool path of any other type. The relationship between machining efficiency and three key variables, tool feed direction, cutter shape, and surface shape, is revealed. The newly introduced principle is used in planning tool paths of a sculptured surface to demonstrate the advantages of the steepest-ascending tool paths. This new tool path scheme is further integrated into the more advanced steepest-directed and iso-cusped (SDIC) tool path generation technique. Applications of the new tool path principle and the SDIC tool paths to the machining of sculptured parts are demonstrated.


2001 ◽  
Author(s):  
Zhiming Ji ◽  
Zhenqun Li

Abstract The dramatic departure in structure of the hexapod machine tools from the traditional five-axis machines leads to the question: can the planning and control methods for the traditional CNC machines be used for the hexapod machine tools? We studied several tool motion characteristics, such as Jocabian matrices, path tracking errors and the extra degree of freedom (e-DOF), and found that the traditional five-axis planning methods cannot take into consideration of the kinematics performance variation and the e-DOF in a hexapod. A kinematics-based tool path planning scheme for the hexapods is therefore proposed. It combines the traditional tool path planning with the kinematic condition optimization. The optimization is a two-step process. First a high accuracy zone of the workspace is identified globally for the placement of the part. Then a set of 5-DOF tool paths is generated and extended to a set of 6-DOF tool paths based on the local planning of e-DOF. Finally the relationship between the e-DOF and the stiffness of the Hexapods, another factor in the use of e-DOF, are discussed.


2007 ◽  
Vol 10-12 ◽  
pp. 308-311
Author(s):  
Li Cheng Fan ◽  
L.N. Sun ◽  
Zhi Jiang Du

In 3-axis NC machining, most algorithms of the sculptured surface tool-path generation are valid for ball-cutter, and the axes are designed to realize pure translation. A tool-path generation algorithm using taper-cuter is proposed in this article. And one axis of the 3-axis NC tool machine is designed to realize swing motion. The Stereo Lithography (STL) model is the most popular triangular mesh approximation of the 3D surface model. Considering the special swing mechanical and taper-cutter, arc-zigzag tool-path planning and deform Z-map grid methods are proposed, which incorporate triangular vertexes method and the Z-map method. Finally, some simulation and experiment results are provided.


2014 ◽  
Vol 800-801 ◽  
pp. 654-659
Author(s):  
Ming Yang Wu ◽  
Rui Zhang ◽  
Yao Nan Cheng ◽  
Yue Zhang ◽  
Shuo An ◽  
...  

The impeller is an important typical part of machinery and equipment industry, and is widely used in energy and power, aerospace, petrochemical, metallurgy and other fields. However, due to the complex shape of the impeller blades, forming more difficult. Flank milling have many advantages, such as forming good accuracy, high efficiency. Therefore, in the paper will choose flank milling for impeller milling. Based on the properties of titanium alloy material and the external characteristics of the impeller blades, proposed control method for machining distortion of impeller blades. Using three offset method to calculate the initial tool position of cylindrical cutter flank milling undevelopable ruled surface, then calculate the initial tool position of cone ball cutter to plan tool path of milling. Through the VERICUT software to simulate the whole process of the impeller flank milling, in order to verify the tool path planning and determine the interference between the tool and the workpiece, the tool and the workpiece does not occur. Finally, through experiments to verify the feasibility of planning algorithm. The trajectory planning and simulation of flank milling titanium impeller blades are foundation of improvement the processing efficiency of the impeller blades and better surface quality.


Author(s):  
Zezhong C. Chen ◽  
Zuomin Dong ◽  
Geoffrey W. Vickers

Some sculptured parts with complex free-form surfaces usually require expensive 5-axis CNC machining. In this work, a cost-effective and practical solution to the 5-axis sculptured part machining – 3-1/2-1/2-axis CNC machining scheme – is discussed. An automatic and optimal tool path planning system for 3-1/2-1/2-axis CNC machining is introduced. The system uses fuzzy pattern recognition method and Voronoi diagram to subdivide a complex sculptured surface into an optimal number of uniform surface patches, finds the optimal cutter/part orientation for each surface patch, and plans 3-axis CNC tool paths for them. This type of machining is carried out by rotating the part to the cutter/part orientations discretely and sequentially using a tilt-rotary table attached to the 3-axis CNC machine. Under each orientation, the corresponding surface patch is machined using the 3-axis CNC tool paths. This tool path planning system can automatically generate efficient tool paths for sculptured parts and make the 3-1/2-1/2-axis CNC machining scheme as an applicable alternative of 5-axis CNC machining method.


Author(s):  
Zezhong C. Chen ◽  
Zuomin Dong ◽  
Geoffrey W. Vickers

Abstract Three-axis CNC milling is often used in sculptured parts machining. Due to the complex shape of the part surfaces, optimal tool path planning can significantly improve machining efficiency. In this work the mechanism of 3-axis CNC machining is examined. The generic formulae of steepest direction of sculptured surface are derived. A mathematical proof of the highest machining efficiency of steepest-directed tool path is provided. The most efficient local scheme, steepest-directed tool path in tool path planning, is proposed. This scheme serves as a theoretical base for applying steepest-directed tool path in tool path generation algorithms for 3-axis CNC machining. The tool path has been used to develop the steepest-directed and iso-cusped (SDIC) tool path generation algorithm. An example of SDIC tool paths of a half-cylinder part illustrates the application of steepest-directed tool path.


Author(s):  
Eric Wang ◽  
Il-Kyu Hwang ◽  
Yong Se Kim

Abstract We describe an automatic machining tool path generation method that combines local tool path planning for machining features with global tool path planning. From the solid model and the tolerance specifications of the part, machining features are automatically recognized, and geometry-based precedence relations are obtained between these features. From this information, the machining sequence, tool selections, and machining conditions are determined. Machining tool paths are then generated automatically for each setup, combining local and global tool paths. Local tool paths to machine each feature are generated using successive offsetting operations. Global tool paths between features are generated incrementally by searching the adjacency graph of feature free spaces, which represents the current free space of the part. Feature free spaces are obtained by expanding the machining features through their fictitious faces. The start and end positions for the local tool paths of each feature are selected based on a heuristic method to minimize the cost of each segment of the global tool path. This automatic tool path generation method is currently being developed as part of a comprehensive machining process planning system.


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