An integrated suite of computer programs is undergoing development to address issues pertaining to the formation of burrs — undesired projections of metal that are generated on edges of workpieces in most metal-cutting operations. Burrs must be removed prior to assembly of machined workpieces, and therefore, plans for manufacturing must usually provide for deburring operations. The developmental software is intended to provide capabilities to (1) predict and minimize the formation of burrs and (2) plan deburring operations to maximize deburring performance and thereby reduce the overall cost of the design-to-fabrication cycles of precisely machined components.

One of the two main programs in this software system is called "BurrEXPERT." With the help of a commercial computer-aided-design (CAD) program as an interface, the BurrEXPERT accepts a drawing of a three-dimensional part (see figure) and assesses the burr-formation potential of the design features of the part under various manufacturing-process plans. The prediction capabilities are driven by a burr-property knowledge base and known burr relationships. These relationships are based on types of manufacturing processes, process parameters, properties of materials, and interactions among part geometries, tool geometries, and tool paths. By interactively and iteratively predicting the sizes, shapes, and locations of burrs, users can plan machining and edge-finishing processes, thereby shortening the design-to-fabrication cycle.

In a Typical Use of the BurrEXPERT, the user seeks to predict and minimize the burrs that would be formed in drilling intersecting holes in a block destined to become a valve body. As development continues, DEXTER (and eventually other software "experts") will be selectable from the menu.

The other main program in this system is the Deburring Expert (DEXTER). When fully developed, the DEXTER will guide the user in selecting candidate edge-finishing processes, by use of a decision strategy driven by a deburring knowledge base. Using predicted observable burr attributes of a part, the DEXTER will match the capabilities and limitations of deburring processes to the characteristics of the part, the burrs on the part, and the desired edges on the part. The DEXTER will evaluate the overall applicability of the processes in the deburring knowledge base to the features on the part. Upon completion of its evaluation, the DEXTER will present a selection of candidate deburring processes. The user can then choose to examine still images, multimedia video images, and animations to obtain detailed information about each candidate deburring process.

Ultimately, the BurrEXPERT will be integrated with the DEXTER to form the Edge Finishing Master software package, so that reasoning about strategies for the prediction and minimization of burrs can be integrated directly with reasoning about the burr-removal process. The Edge Finishing Master will thus serve as a "seamless" edge-finishing software tool for use by design and manufacturing engineers at all levels of integration between design and manufacturing functions, including the highest level of integration, where the outcome of manufacturing of parts is simulated during the design stage. High levels of integration between design and manufacturing will enable designers to perform computational simulations to achieve optimal balances between opposing metrics (e.g., surface finish vs. total cost of production).

This work was done by Julie M. Stein, Andrew Chang, and David Dornfeld of Integrated Constructs, Inc., for Lewis Research Center. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com under the Manufacturing/Fabrication category. Inquiries concerning rights for the commercial use of this invention should be addressed to

NASA Lewis Research Center, Commercial Technology Office, Attn: Tech Brief Patent Status, Mail Stop 7-3, 21000 Brookpark Road, Cleveland, Ohio 44135.

Refer to LEW-16622.


NASA Tech Briefs Magazine

This article first appeared in the April, 1999 issue of NASA Tech Briefs Magazine.

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