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Autokinetics is a Rochester Hills MI design firm working with Armco, a supplier of stainless steel. Together, they have developed an architecture that replaces the traditional stamped and spot welded steel unibody with a novel stainless steel spaceframe architecture. Fabrication Rollformings Thin wall castings Progressive die stampings Plastic support and exterior panels Assembly - Spot, laser, and MIG welding Relative to conventional steel unibodies, the Autokinetics spaceframe architecture offers a number of projected advantages. Substantial mass reduction Increased safety Improved ride and NVH More flexible packaging Lower lifecycle impact Potential for paint shop elimination The obvious question that arises, and the one that this paper will answer, is: How does the Autokinetics spaceframe architecture compete on cost?

In the past decade, the demand for and development of tailor-welded blanks (TWBs) has increased dramatically. TWBs help reduce body mass, piece count and assembly costs, while potentially reducing overall cost. IBIS Associates, Inc. has performed a cost analysis of tailor welded blank manufacturing through the use of Technical Cost Modeling (TCM), a methodology used to simulate fabrication and assembly processes. IBIS has chosen the automobile door inner panel for comparison of TWBs and conventionally stamped door inners with added reinforcements. Manufacturing costs are broken down by operation for variable costs (material, direct labor, utility), and fixed costs (equipment, tooling, building, overhead labor, maintenance, and cost of capital). Analyses yield information valuable to process selection by comparing cost as a function of manufacturing method, process yield, production volume, and process rate.

Hyrdroformed tubes have seen use in the aerospace industry for many years and are seeing increased use in the automotive body-in-white (BIW). The automotive industry has chosen to use hydroformings for a number of reasons including reduced part weight, piece count reduction, and the flexibility to form complex shapes of varying wall thickness. With all of these potential advantages, still one more provides the greatest incentive to switch from a stamped assembly to a hydroformed tube: the ability to reduce cost. It is generally accepted that hydroformings can indeed be cost effective to produce, yet the question remains: when should a stamped assembly be replaced by a hydroformed component? This paper will attempt to answer the question above by laying out several case studies and comparing their direct manufacturing costs.

Despite repeated challenges from alternative materials and processes, the stamped and spot welded steel unibody remains the near-unanimous choice of automakers for vehicle body-in-white (BIW) structures and exterior panels in volume production. Conventional steel's only weakness is mass; aluminum and polymer composites offer the potential for considerable mass savings, but generally at a higher cost. Efforts within the automakers as well as by outside organizations such as the international steel industry's Ultra Light Steel Auto Body (ULSAB) program are underway to improve the steel uni-body's mass and cost position. To reduce cost, it is first necessary to identify cost. The measurement of cost for a complex system such as an automobile BIW is far from a trivial task. This paper presents an analytical approach to understanding the manufacturing cost for a conventional steel unibody. The results of this cost analysis are then used to outline a strategy for future cost reduction.

The Partnership for a New Generation of Vehicles (PNGV), a collaborative government-industry R&D program, has laid out and initiated a plan for a “Supercar” with the following specifications: a fuel economy of 80 miles per gallon (2.9 liters/100 km), size comparable to a midsize, four door sedan, equivalent function in other performance areas, and cost commensurate with that of today's automobile. Together, the performance and cost goals are formidable to say the least. The PNGV projects that a 50% mass savings in the “body-in-white” (BIW) is a necessary contribution to meet the 80 mpg goal. The two most likely materials systems to meet the mass reduction goal are aluminum and carbon fiber reinforced polymer composites, neither of which are inexpensive relative to today's steel unibody.