M.S. Thesis Presentation by Brian D. Harper

(Dr. David Rosen, advisor)

"CAD Methods to Support Automated De- and Remanufacture Assessments"


De- and remanufacture involves the reclamation, refurbishment, and return to service of a product or component that has expended its useful life cycle. Automated assessments of a product's ease of de- or remanufacture can facilitate design for the life cycle. Automation can be facilitated by inferring information relevant to the assessments from information contained in the CAD model, as well as by incorporating additional information relevant to life-cycle assessments into CAD models.

The principal question to be addressed in this thesis is "How can CAD tools be used and extended to support design for de- and remanufacture?" It is believed that both of the above methods can be utilized to automatically determine (to a large extent) metrics for assembly, disassembly, inspection, refurbishment, and replacement. These metrics can then be combined to obtain an index that characterizes the ease of de- and remanufacture of a product. In order to gather the information necessary for these metrics from a CAD system, the following tasks need to be accomplished:

~ Partially automated disassembly sequencing: previous work involving partial ordering of a disassembly sequence for a CAD model will be combined with knowledge from the designer to obtain a feasible disassembly sequence.

· Integration of fasteners into the product model: in order to infer assembly and disassembly time, the explicit representation of fasteners in the product data model is necessary. This implementation will automate the instantiation of fasteners to a large extent, allowing the designer to explore 'what if' situations involving changes in fastener type.

~ Automatic determination of criteria for ideal number of parts: Boothroyd and Dewhurst introduce the ideal number of parts as a means to determine a design's ease of assembly. This concept can be extended and included in other life-cycle assessments as well. By automatically evaluating some of the criteria for this metric, automated life-cycle assessments can be facilitated.

A case study involving the de- and remanufacture of an automotive instrument cluster is utilized to verify that the automated assessments are both correct and useful.