language: en

[To appear, Computer Aided Design, 1995 or 1996]

GENERATING REDESIGN SUGGESTIONS TO REDUCE SETUP COST: A STEP TOWARDS AUTOMATED REDESIGN

Diganta Das
Mechanical Engr. Dept. and Institute for Systems Research, University of Maryland
College Park, MD 20742
diganta@cs.umd.edu
Satyandra K. Gupta
The Robotics Institute Carnegie Mellon University
Pittsburgh, PA 15213
skgupta@isl1.ri.cmu.edu
Dana S. Nau
Dept. of Computer Science and Institute for Systems Research, University of Maryland
College Park, MD 20742
nau@cs.umd.edu

Abstract All mechanical designs pass through a series of formal and informal redesign steps, involving the analysis of functionality, manufacturability, cost and other life-cycle factors. The speed and efficacy of these steps has a major influence on the lead time of the product from conceptualization to launching. In this paper we propose a methodology for automatically generating redesign suggestions for reducing setup costs for machined parts. Given an interpretation of the design as a collection of machinable features, our approach is to generate alternate machining features by making geometric changes to the original features, and add them to the feature set of the original part to create an extended feature set. The designer may provide restrictions on the design indicating the type and extent of modifications allowed on certain faces and volumes, in which case all redesign suggestions generated by our approach honor those restrictions. By taking combinations of features from the extended feature set generated above, we can generate modified versions of the original design that still satisfy the designer's intent. By considering precedence constraints and approach directions for the machining operations as well as simple fixturability constraints, we can estimate the setup time that will be required for each design. Any modified design whose setup time is less than that of the original design can be presented to the designer as a possible way to modify the original design.