An Algorithm for a Near Optimal NC Path Generation in Staircase (Lase) Traversal of Convex Polygonal Surfaces

1999 ◽  
Vol 122 (1) ◽  
pp. 182-190 ◽  
Author(s):  
S. V. Kamarthi ◽  
S. T. S. Bukkapatnam ◽  
S. Hsieh
Keyword(s):  
Rapid Prototyping ◽  
Path Length ◽  
Tool Path ◽  
Path Generation ◽  
Convex Polygons ◽  
Sweep Angle ◽  
Pocket Milling ◽  
Different Shapes ◽  
Path Lengths ◽  
Better Than

This paper presents an analytical model of the tool path for staircase traversal of convex polygonal surfaces, and an algorithm—referred to as OPTPATH—developed based on the model to find the sweep angle that gives a near optimal tool path length. The OPTPATH algorithm can be used for staircase traversal with or without (i) overlaps between successive sweep passes, and (ii) rapid traversal along edge passes. This flexibility of OPTPATH renders it applicable not only to conventional operations such as face and pocket milling, but also to other processes such as robotic deburring, rapid prototyping, and robotic spray painting. The effective tool path lengths provided by OPTPATH are compared with those given by the following two algorithms: (i) a common industrial heuristic—referred to as the IH algorithm—and (ii) an algorithm proposed by Prabhu et al. (Prabhu, P. V., Gramopadhye, A. K., and Wang, H. P., 1990, Int. J. Prod. Res., 28, No. 1, pp. 101–130) referred to as PGW algorithm. This comparison is conducted using 100 randomly generated convex polygons of different shapes and a set of seven different tool diameters. It is found that OPTPATH performs better than both the IH as well as PGW algorithms. The superiority of OPTPATH over the two algorithms becomes more pronounced for large tool diameters. [S1087-1357(00)71501-2]

Adaptive tool-path generation of rapid prototyping for complex product models

2011 ◽  
Vol 30 (3) ◽  
pp. 154-164 ◽  
Author(s):  
G.Q. Jin ◽  
W.D. Li ◽  
C.F. Tsai ◽  
L. Wang
Keyword(s):  
Rapid Prototyping ◽  
Tool Path ◽  
Tool Path Generation ◽  
Path Generation ◽  
Complex Product ◽  
Product Models ◽  
Adaptive Tool

Development of a Forging-Type Rapid Prototyping System (Tool Path Generation Considering Deformation Process)

2010 ◽  
Vol 4 (6) ◽  
pp. 530-535 ◽  
Author(s):  
Naoki Asakawa ◽  
◽  
Hidetake Tanaka ◽  
Keyword(s):  
Rapid Prototyping ◽  
Deformation Process ◽  
Degrees Of Freedom ◽  
Tool Path ◽  
Industrial Robot ◽  
Tool Path Generation ◽  
Path Generation ◽  
Parametric Curve ◽  
Curve Interpolation ◽  
Rapid Prototyping System

This study deals with the development of a CAM system that considers the deforming process for a forgingtype rapid prototyping system. An industrial robot that has high degrees of freedom is employed to handle the hammering unit. A special CAM system suitable for the hammering work is developed using parametric curve interpolation. The tool path is generated considering continuity in order to avoid fracture or breakage. Using the system, metal hammering experiments are carried out. The system successfully shaped workpieces according to the generated path. The experimental results confirm the ability of the system to improve, owing to the parametric curve interpolation, forming properties.

scholarly journals Communicability distance reveals hidden patterns of Alzheimer disease

2020 ◽  
Author(s):  
Eufemia Lella ◽  
Ernesto Estrada
Keyword(s):  
Alzheimer Disease ◽  
Path Length ◽  
Brain Regions ◽  
Brain Network ◽  
Efficient System ◽  
Brain Hemispheres ◽  
Disconnection Syndrome ◽  
Path Lengths ◽  
The Brain ◽  
Better Than

AbstractThe communicability distance between pairs of regions in human brain is used as a quantitative proxy for studying Alzheimer disease. Using this distance we obtain the shortest communicability path lengths between different regions of brain networks from Alzheimer diseased (AD) patients and healthy cohorts (HC). We show that the shortest communicability path length is significantly better than the shortest topological path length in distinguishing AD patients from HC. Based on this approach we identify 399 pairs of brain regions for which there are very significant changes in the shortest communicability path length after AD appears. We find that 42% of these regions interconnect both brain hemispheres, 28% connect regions inside the left hemisphere only and 20% affects vermis connection with brain hemispheres. These findings clearly agree with the disconnection syndrome hypothesis of Alzheimer disease. Finally, we show that in 76.9% damaged brain regions the shortest communicability path length drops in AD in relation to HC. This counterintuitive finding indicates that AD transforms the brain network into a more efficient system from the perspective of the transmission of the disease, because it drops the circulability of the disease factor around the brain regions in relation to its transmissibility to other regions.

Enhanced strategy for milling corners

2002 ◽  
Vol 216 (8) ◽  
pp. 1135-1154 ◽  
Author(s):  
H S Choy ◽  
K W Chan
Keyword(s):  
Computer Aided Design ◽  
Tool Path ◽  
Tool Path Generation ◽  
Path Generation ◽  
Practical Applications ◽  
Cutting Resistance ◽  
Pocket Milling ◽  
Cad Cam ◽  
Contour Parallel Tool Path ◽  
Aided Design

Tool path generation based on contour-parallel offset has many practical applications, especially in pocket milling. However, the tool path segments offset from the pocket boundary usually form many corners. In milling operation, these corners with accumulated material will have an adverse effect on milling performance. This paper proposes an improved numerically controlled (NC) tool path pattern for pocket milling. Bow-like tool path segments are appended to a conventional contour-parallel tool path at the corner positions. The cutter loops along the appended tool path so that the corner material is machined progressively in several passes. By adjusting the number of appended tool path loops, cutting resistance can be controlled. The proposed tool path generation for dealing with different corner shapes was implemented as an addon user function in a computer aided design/manufacture (CAD/CAM) system. Cutting tests confirmed that the proposed tool path pattern is useful for clearing accumulated material at pocket corners while maintaining a higher cutting stability.

An Overview of STL Model Offset

2012 ◽  
Vol 542-543 ◽  
pp. 499-502
Author(s):  
Hu Zhu ◽  
Xue Yong Jing ◽  
Peng Zhang
Keyword(s):  
Rapid Prototyping ◽  
Tool Path ◽  
Tool Path Generation ◽  
Numerical Control ◽  
Model Generation ◽  
Path Generation ◽  
Numerical Control Machining ◽  
Stl Model

The offset models of STL (Stereo Lithography) are useful in many applications such as interference-free tool path generation in numerical control machining, hollow or shelled model generation in rapid prototyping. So the methods for STL model offset are very important. In the paper, an overview of the STL models offset methods is presented in brief.

Tool Path Optimization of 2D Contour Considering Stock Boundary

2012 ◽  
Vol 251 ◽  
pp. 169-172
Author(s):  
Fu Zhong Wu
Keyword(s):  
Present Method ◽  
Tool Path ◽  
Three Dimensional ◽  
Boundary Curve ◽  
Tool Path Generation ◽  
Path Optimization ◽  
Path Generation ◽  
Offset Curves ◽  
Measuring Machine ◽  
Tool Diameter

Based on analyzing the existing algorithms, a novel tool path generation of 2D contour considering stock boundary is presented. Firstly the boundary points of stock are obtained by three-dimensional measuring machine. And the boundary curve is constructed by method of features identifying. The stock boundary is offset toward outside with tool diameter. An enclosed region is formed between the contour curves and the offset curves of stock boundary. The tool path is generated by form of parallel spiral by offsetting the stock boundary in the enclosed region. Finally the validity of present method is demonstrated by an example.

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