Abstract One of the advantages of feature-based design is that it provides data which are defined as parameters of features in readily available forms for tasks from design through manufacturing. It can thus facilitate the integration of CAD and CAM. However, not all design features are features required in down stream applications and not all parameters or data can be predefined in the features. One of the significant examples is property that is formed by feature interactions. For example, the interaction of a positive feature and a negative feature induces a wall thickness change that might cause defects in a part. Therefore, the identification of the wall thickness change by detecting the feature interaction is required in the moldability assessment. The work presented in this paper deals with the extraction of geometric characteristics in feature-based design for manufacturability assessment. We focus on the manufacturability assessment of discrete parts with emphasis on a net shape process—injection molding. The definition, derivation and representation of the spatial relationships between features are described. The geometric characteristics formed by feature interactions are generalized as significant items, such as “depth”, “thickness”, “height” etc. based on the generalization of feature shapes. Reasoning on feature interactions and extraction of geometric characteristics is treated as a refinement procedure. High-level spatial relationships—“is_in”, “adjacent_to” and “coplanar” as well as their geometric details are first derived. The significant items formed from feature interactions are then computed based on the detailed spatial relationships. This work was implemented in a computer-aided concurrent product and process development environment to support molding product design assessment.
[1]
Giuseppe Catania,et al.
Form-features for Mechanical Design and Manufacturing
,
1991
.
[2]
Yuh-Min Chen.
Development of a computer-aided concurrent net shape product and process development environment
,
1997
.
[3]
D. C. Anderson,et al.
Geometric reasoning in feature-based design and process planning
,
1990,
Comput. Graph..
[4]
Aristides A. G. Requicha,et al.
Feature Recognition from CAD Models
,
1998,
IEEE Computer Graphics and Applications.
[5]
Yuh-Min Chen,et al.
Computer-aided feature-based design for net shape manufacturing
,
1997
.
[6]
Jarek Rossignac,et al.
A Road Map To Solid Modeling
,
1996,
IEEE Trans. Vis. Comput. Graph..
[7]
Bartholomew O. Nnaji,et al.
Feature reasoning for automatic robotic assembly and machining in polyhedral representation
,
1990
.
[8]
Ming-Hsuan Yang.
Recognizing machining features through partial constraint satisfaction
,
1997,
1997 IEEE International Conference on Systems, Man, and Cybernetics. Computational Cybernetics and Simulation.
[9]
Donald V. Rosato,et al.
Injection Molding Handbook
,
1985
.
[10]
Jami J. Shah,et al.
Functional requirements and conceptual design of the feature-based modelling system
,
1988
.
[11]
Utpal Roy,et al.
Feature-based representational scheme of a solid modeler for providing dimensioning and tolerancing information
,
1988
.
[12]
John R. Dixon,et al.
Expert systems for mechanical design: Examples of symbolic representations of design geometries
,
1987,
Engineering with Computers.
[13]
Jarek Rossignac,et al.
Issues on feature-based editing and interrogation of solid models
,
1990,
Comput. Graph..