THE REFLEX-FREE HULL

2004 ◽  
Vol 14 (06) ◽  
pp. 453-474 ◽  
Author(s):  
HEE-KAP AHN ◽  
SIU-WING CHENG ◽  
OTFRIED CHEONG ◽  
JACK SNOEYINK
Keyword(s):  
Computer Aided Design ◽  
Combinatorial Complexity ◽  
Challenging Problem ◽  
Planar Surfaces ◽  
Computer Aided ◽  
Design And Manufacturing ◽  
Polyhedral Set ◽  
Aided Design

We propose a hull operator, the reflex-free hull, that allows us to define a 3D analogue to bays in polygons. The reflex-free hull allows a rich set of topological types, yet for polyhedral input with n edges, it remains a polyhedral set with O(n) edges. This is in contrast to other possible hull definitions that give non-planar surfaces and higher combinatorial complexity. The reflex-free hull is related to identifying cavities in computer aided design and manufacturing, but we sketch examples to indicate that computing a reflex-free hull will be a challenging problem.

The Application of Computer Techniques in the Design and Manufacturing of Timing Scrolls

1993 ◽  
Vol 207 (2) ◽  
pp. 99-108
Author(s):  
L Q Tang ◽  
D N Moreton
Keyword(s):  
Dynamic Characteristic ◽  
Computer Aided Design ◽  
Numerical Control ◽  
Feeding Mechanism ◽  
Control Techniques ◽  
Computer Aided ◽  
Design And Manufacturing ◽  
Manufacturing Techniques ◽  
Aided Design ◽  
Design And Manufacture

The timing scroll is an important feeding mechanism on packaging lines. As packaging line speeds have increased and the shape of containers has become more diverse, the techniques used for the design and manufacture of such timing scrolls have become critical for successful packaging line performance. Since 1980, various techniques have evolved to improve scroll design, manufacture and the associated line performance. In recent years, as CAD (computer aided design), CAM (computer aided manufacture) and CNC (computer numerical control) techniques have evolved, scroll design and manufacturing techniques began to be linked with computer techniques. In this paper, a scroll design and manufacturing package is presented which can be run on a minicomputer, such as a μ-VAX on an IBM PC clone. This scroll package can produce a timing scroll for any type of container with a correct pocket shape and good dynamic characteristic. Tests using carefully chosen containers have been made using this package and the results indicate that the scrolls obtained by this package have the correct pocket shape and good line performance. However, the design of a good pick-up geometry for some container shapes remains a problem.

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