Institute for Systems Research
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Item Extracting Alternative Machining Features: Al Algorithmic Approach(1994) Regli, W.C.; Gupta, Satyandra K.; Nau, D.S.; ISRAutomated recognition of features from CAD models has been attempted for a wide range of application domains. In this paper we address the problem of representing and recognizing the complete class of features in alternative interpretations for a given design. We present a formalism for representing feature- based design alternatives and a methodology for recognizing a class of machinable features. Our approach handles a class of volumetric features that describe material removal volumes made by operations on the three-axis vertical machining centers including: drilling, pocket-, slot-, and face-miling, chamfering, filleting, and blended surfaces. Our approach recognizes intersecting features, and is complete over all features in our class, i.e. for any given part, the algorithm produces a set containing all features in our class that correspond to possible operations for machining that part. This property is of particular significance in applications where consideration of different manufacturing alternatives is crucial. In addition, we have shown that the algorithms are, in the worst-case, euqdratic in the number solid modeling operations. This approach employs a class of machinable features expressible as MRSEVs ( a STEP- based library of machining features). An implementation of these algorithms has been done using the ACISsolid modeler and the NIH C++ class library.Item Integrating DFM with CAD through Design Critiquing(1994) Gupta, Satyandra K.; Regli, W.C.; Nau, D.S.; ISRIn research on concurrent engineering and engineering design, the increasing use of design for manufacturability(DFM) is expanding the scope of traditional design activities in order to identify and eliminate manufacturing problems during the design stage. However, manufacturing a product generally involves many different kinds of manufacturing activities, each having different characteristics. A design that is good for one kind of activity may not be good for another; for example, a design that is easy to assemble may not be easy to machine. One obstacle to DFM is the difficulty involved in building a single system that can handle the various manufacturing domains relevant to a design.In this paper, we propose an architecture for integrating CAD with DFM. This involves the use of multiple critiquing systems, each one dedicated to one type of manufacturing domain. In the proposed framework, as the designer creates a design, a number of critiquing systems analyze its manufacturability with respect to different manufacturing domains (machining, fixturing, assembly, inspection, and, so forth), and offer advice about potential ways of improving the design.
We anticipate that this approach can be used to build an environment that will allow designers to create high-quality products that can be manufactured more economically. This will reduce the need for redesign, thus reducing product cost and lead time.
Item Feature Recognition for Manufacturability Analysis(1994) Regli, W.C.; Gupta, Satyandra K.; Nau, D.S.; ISRWhile automated recognition of features has been attempted for a wide range of applications, no single existing approach possesses the functionality required to perform manufacturability analysis. In this paper, we present a methodology for taking a CAD model and extracting a set of machinable features suitable for generating all alternative interpretations of the model as collections of MRSEVs (Material Removal Shape Element Volumes, a STEP-based library of machining, features). This set of MRSEVs is to be employed for manufacturability analysis. The algorithm handles a variety of features including those describing holes, pockets, slots, and chamfering and filleting operations. In addition, it considers elementary accessibility constraints for these features and is provably complete over a, significant class of machinable parts the features describe. Further, the approach has low-order polynomial-time worst-case complexity.Item Building MRSEV Models for CAM Applications(1993) Gupta, Satyandra K.; Kramer, Thomas R.; Nau, D.S.; Regli, W.C.; Zhang, G.M.; ISRIntegrating CAD and CAM applications, one major problems is how to interpret CAD information in a manner that makes sense for CAM. Our goal is to develop a general approach that can be used with a variety of CAD and CAM applications for the manufacture of machined parts.In particular, we present a methodology for taking a CAD model, extracting alternative interpretations of the model as collections of MRSEVs (Material Removal Shape Element Volumes, a STEP-based library of machining features), and evaluating these interpretations to determine which one is optimal. The evaluation criteria may be defined by the user, in order to select the best interpretation for the particular application at hand.
Item Recognition of Volumetric Features from CAD Models: Problem Formalization and Algorithms(1993) Regli, W.C.; Nau, D.S.; ISRAutomated recognition of features from CAD models has been attempted for a wide range of application domains in mechanical engineering. However, the absence of a clear mathematical formalism for the problem has made it difficult to develop a general approach - and thus most of these methods are limited in scope.In this paper, we develop a formalization of the problem of recognizing a class of machinable features expressed as MRSEVs ( a PDES/STEP library of machining features) [19], and an algorithm for solving this problem. Some of the characteristics of this approach are: the algorithm handles a large variety of hole and pocket features along with elementary accessibility constraints and blends for those features; it is provably complete, even if the features interest with each other in complex ways; it has O(n4) worst-case time complexity,
Item A Survey of Automated Feature Recognition Techniques(1992) Regli, W.C.; ISRAutomated feature recognition has been attempted through many methodologies for a wide range of application domains. This survey focuses on its use for geometric reasoning problems in mechanical engineering. Many of these methods are greatly limited in scope. Often they perform on a restricted class of objects with confining feature definitions. Furthermore, problems with interactions between features can render objects unrecognizable. This survey presents an overview of many of the works in this area. Included are descriptions of the approaches and an analysis of their abilities to provide a definition for and solution to the general problem of recognizing features from a solid model. It is hoped that previous research will provide the guidance for the development of a feature recognition system that is complete over a mathematically definable set of objects.