Deptula, L. and Noah, A., "Estimating the Cost Impact of Lightweighting Automotive Closures," SAE Technical Paper 2015-01-0581, 2015, doi:10.4271/2015-01-0581.
The approaching corporate average fuel economy (CAFE) regulations will again increase with new model years (MY). The U.S. Government finalized a regulation requiring cars and light trucks average 54.5 mpg fuel economy for MY2025. Vehicle manufacturers recognize removing weight is a key feature to meeting their targets for fuel economy and emission reductions. One common OEM strategy is the implementation of incremental weight reductions to attain these goals. The automotive industry continues to look for opportunities to reduce weight and cost while continually increasing performance and safety. Lightweighting technologies enhance vehicle performance, (fuel economy, acceleration, braking and emissions). New materials are available to reduce weight; however the incremental cost for the weight reduction can be prohibitive. This study will encompass the utilization of lightweight materials, as well as current and evolving manufacturing processes. Where reducing weight while achieving performance targets for dent resistance, stiffness, and crash-worthiness are the goals; the key is to attain a lightweight assembly that assists in meeting the fuel economy targets, through optimized part design and/or material substitution.Determining the cost to meet incremental light weighting objectives should be standardized using the cost per pound saved unit of measure. Previous studies have been conducted estimating that weight reductions using higher strength steels can cost 50 cents per each pound reduced, with claims that savings from substituting aluminum can cost $1.50-2.00 per pound saved. Automotive manufacturers estimate the cost of reductions could reach as high at $7 per pound reduced, while federal regulators estimate a significantly lower cost.Our objective is to address this discrepancy between these cost estimates for lightweighting. Current methods of measuring the cost of lightweight are often done through a piece cost evaluation in $/lb, or $/Kg. Another method includes evaluating costs from a tear down know as bottom up estimation. We will also evaluate how changes in lightweighting strategies affect direct manufacturing cost (DMC). We will examine the direct manufacturing costs to determine the cost feasibility to manufacture lightweight vehicle closures (doors, hood, and decklids). We wish to determine the manufacturers' cost impact caused by rapid change in adaptation of incremental lightweighting materials and processes applied to vehicles as opposed to mature manufacturing practices.The research will focus on methods used to create automotive closures. We will evaluate closure case studies, showing the cost factors of using different materials and processes evaluating the savings in weight compared to a baseline closure. We will explain our method of cost estimation to achieve light weighting in a way to better evaluate cost to meet these regulations on fuel consumption and emissions across the auto industry; to better inform the industry and regulators of the true cost of reducing the mass of automobiles.