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Design advisors.

Boothroyd Dewhurst Inc., in Wakefield, R.I., has released new versions of its programs for designing products that are easier to assemble and that are friendlier to the environment. Like previous versions, Design for Assembly (DFA) version 8.2 guides design engineers through a systematic analysis of a proposed design's ease of assembly. New features include the ability to import existing cost-estimate data, a tool for assessing designs' quality, and databases libraries that have been expanded and can now be fully edited.

With DFA 8.2, machining, injection-molding, and sheet-metalworking cost estimates can be imported by selecting the appropriate cost-estimating module on a drop-down menu. For each part in the product, designers are asked questions about whether the part is necessary and whether it presents handling, insertion, or fetching difficulties. As questions are answered, DFA's structure chart updates and displays the resulting assembly time or cost per part.

The new product quality assessment tool provides a means of predicting assembly quality at the design stage. As selections are made in the product quality assessment window, the likely percentage of defective assemblies for a proposed design can be predicted. The predicted value for design quality is given as a percentage of defective products that are likely to require corrective action after product inspection or testing, or during the warranty period. Once DFA analysis is complete, the data associated with each part in the product can be viewed using a worksheet or the program's product review table and then sorted according to time and cost criteria.

Design for Environment (DFE) release 1.1 works in tandem with DFA analyses to help designers evaluate and optimize the disassembly sequences of products for end-of-life recovery. DFE is intended to make it easier for concurrent engineering teams to identify and consider realistic tradeoffs between the costs and benefits of producing environmentally friendly designs.

New features in DFE 1.1 include the ability to edit the recycled value of materials, the materials database, and the manufacturing-process database, and to add data on different types of batteries and additional thermoset plastics to the materials database. The manufacturing-processes database has also been expanded - by approximately 300 percent - to include knowledge on metal casting, electrodischarge machining, and metal forming.

The software works by asking the user questions about product structure, disassembly and disposal costs, and ecological effects. Results appear on an end-of-life evaluation graph, which summarizes the entire DFE product analysis and allows tracking of disassembly costs and environmental impacts. Alternative designs or disassembly sequences can be compared on a single graph, making it simpler for design engineers to perform "what-if" assessments.

Data generated by DFE analyses provide information about the associated cost benefits for various end-of-life options, including material recycling, part remanufacture or reuse, and disposal through deposition in landfills or incineration. DFE analyses also help engineers identify where in the disassembly sequence future disassembly is of no benefit either economically or environmentally. To determine the environmental impact of products, materials, energy, and toxicity (MET) points are applied as a value-assessment metric to the initial manufacturing stage and to the disposal, reuse, or recycling of a product at the end of its service life.

DFA 8.2 and DFE 1.1 operate on Windows 3.1, Windows 95, and Windows NT platforms. Additional information can be obtained on the World Wide Web at
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Title Annotation:Boothroyd Dewhurst Inc.'s Design for Assembly version 8.2 software
Author:Deitz, Dan
Publication:Mechanical Engineering-CIME
Date:Jul 1, 1998
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