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Designing For Cost / Affordability : Developing A Total Cost Model For Plastic Injection Molded Parts

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1996 Annual Conference


Washington, District of Columbia

Publication Date

June 23, 1996

Start Date

June 23, 1996

End Date

June 26, 1996



Page Count


Page Numbers

1.145.1 - 1.145.6



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Paper Authors

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Donald N. Merino

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D. W. Merino

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NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract

1 . Session 1239 .

DESIGNING FOR COST / AFFORDABILITY : Developing A Total Cost Model For Plastic Injection Molded Parts

D. W. Merino , D. N. Merino , Ph.D. P. E. Engineering Information Inc. / Stevens Institute of Technology Hoboken, NJ

Introduction Engineering design involves using scientific principles to provide economical solutions that satisfy 3 technical requirements . Increasing global competitiveness has made economical solutions even more important than it has been in the past. The need to Design for Cost or Design for Affordability has become dominant for many products in many industries.

Target Costs in Engineering Design A new engineering design paradigm has emerged where global competitors set target costs for products before engaging in engineering design’. Target costs are the costs products must meet in order to realize a profit and create or penetrate a market. Defining Quality as meeting customers’ specifications must now be amended to include the price the customer is willing to pay. A concurrent engineering approach with multi- disciplinary teams is used to design plastic parts that meet customer requirements including cost. While these teams use a variety of tools, there is a lack of cost prediction software packages for plastic parts. This paper discusses the development of an engineering economic model for injection molding.

Design for Cost/Affordability in Engineering Design For engineering design teams to be effective they should continually assess cost tradeoffs and then use this information to constantly improve the cost estimates as they progress from feasibility to the final design. Initial estimates developed in the conceptual design phase are updated during the definition and scoping phases of the design. These design teams quickly learn what other industries already know. The accuracy of the cost estimate increases as the design cycle progresses (Figure 1). Typically a knowledgeable designer should be able to estimate the cost of a plastic part to within + 30°/0 to t50°/0 at the initial feasibility stage. As the project progresses and the design team spends more time they can increase the accuracy of the estimate. Increased effort in engineering design and cost estimation results in increased accuracy. A

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Project Stages ~ Increasing Effort Figure 1 Trade offs in Cost Estimation : Accuracy vs. Effort ---- ?@& 1996 ASEE Annual Conference Proceedings } ‘.>+,~yy’..$

Merino, D. N., & Merino, D. W. (1996, June), Designing For Cost / Affordability : Developing A Total Cost Model For Plastic Injection Molded Parts Paper presented at 1996 Annual Conference, Washington, District of Columbia. 10.18260/1-2--5971

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