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Journal Article

CoQ Tradeoffs in Manufacturing Process Improvement and Inspection Strategy Selection: A Case Study of Welded Automotive Assemblies

2012-04-16
2012-01-0514
In today's highly competitive automotive markets manufacturers must provide high quality products to survive. Manufacturers can achieve higher levels of quality by changing or improving their manufacturing process and/or by product inspection where many strategies with different cost implications are often available. Cost of Quality (CoQ) reconciles the competing objectives of quality maximization and cost minimization and serves as a useful framework for comparing available manufacturing process and inspection alternatives. In this paper, an analytic CoQ framework is discussed and some key findings are demonstrated using a set of basic inspection strategy scenarios. A case of a welded automotive assembly is chosen to explore the CoQ tradeoffs in inspection strategy selection and the value of welding process improvement. In the assembly process, many individual components are welded in series and each weld is inspected for quality.
Journal Article

An Assessment of the Rare Earth Element Content of Conventional and Electric Vehicles

2012-04-16
2012-01-1061
Rare earths are a group of elements whose availability has been of concern due to monopolistic supply conditions and environmentally unsustainable mining practices. To evaluate the risks of rare earths availability to automakers, a first step is to determine raw material content and value in vehicles. This task is challenging because rare earth elements are used in small quantities, in a large number of components, and by suppliers far upstream in the supply chain. For this work, data on rare earth content reported by vehicle parts suppliers was assessed to estimate the rare earth usage of a typical conventional gasoline engine midsize sedan and a full hybrid sedan. Parts were selected from a large set of reported parts to build a hypothetical typical mid-size sedan. Estimates of rare earth content for vehicles with alternative powertrain and battery technologies were made based on the available parts' data.
Technical Paper

Achieving An Affordable Low Emission Steel Vehicle; An Economic Assessment of the ULSAB-AVC Program Design

2002-03-04
2002-01-0361
Vehicle weight reduction, reduced costs and improved safety performance are the main driving forces behind material selection for automotive applications. These goals are conflicting in nature and solutions will be realized by innovative design, advanced material processing and advanced materials. Advanced high strength steels are engineered materials that provide a remarkable combination of formability, strength, ductility, durability, strain-rate sensitivity and strain hardening characteristics essential to meeting the goals of automotive design. These characteristics act as enablers to cost- and mass-effective solutions. The ULSAB-AVC program demonstrates a solution to these conflicting goals and the advantages that are possible with the utilization of the advance high strength steels and provides a prediction of the material content of future body structures.
Technical Paper

Not the Delorean Revisited: An Assessment of the Competitive Position of a Stainless Steel Body-in-White

1999-09-28
1999-01-3239
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?
Technical Paper

Economic Analysis of Hydro-Mechanical Sheet Metal Forming

1999-09-28
1999-01-3207
Recent industry trends have resulted in growing interest among automakers in low to medium volume manufacturing. The expansion of automobile production into developing economies and the desire to produce specialized vehicles for niche markets have pressed the automakers to find cost effective solutions for manufacturing at low volumes, particularly with regard to sheet metal forming. Conventional high volume stamping operations rely heavily on achieving minimum scale economies which occur at about 200,000 parts per year. These scale economies are mainly dictated by the efficient use of the standard, expensive cast iron dies. These dies can cost well over one million dollars depending on the part, and in return offer tool lives over 5 million strokes. Die investment can be reduced by changing the stamping process technology. Hydro-mechanical forming has been proposed as a promising low volume alternative to conventional stamping.
Technical Paper

Alternative Tooling Technologies for Low Volume Stamping

1999-09-28
1999-01-3216
Low volume manufacturing has become increasingly important for the automotive industry. Globalization trends have led automakers and their suppliers to operate in developing regions where minimum efficient scales can not always be achieved. With proper maintenance, standard cast iron stamping tools can be used to produce millions of parts, but require large investments. Thus at high production volumes, the impact of the tooling investment on individual piece costs is minimized. However, at low volumes there is a substantial cost penalty. In light of the trends towards localized manufacturing and relatively low demands in some developing markets, low cost stamping tools are needed. Several alternate tooling technologies exist, each of which require significantly lower initial investments, but suffer from greatly reduced tool lives. However, the use of these technologies at intermediate to high volumes requires multiple tool sets thus eliminating their cost advantage.
Technical Paper

Economic Analysis of the Ultra Light Steel Auto Body

1998-09-29
982399
Aluminum and polymer composites have long been considered the materials of choice for achieving mass reduction in automotive structures. As consumer and government demand for mass reduction grows, the use of these materials, which have traditionally been more expensive than the incumbent steel, becomes more likely. In response to this growing challenge, the international steel community has joined forces to develop the Ultra Light Steel Auto Body (ULSAB). The resulting design saves mass and increases performance relative to current steel unibodies. Although mass savings are not as dramatic as those achieved by alternative materials, this design offers the potential to be accompanied by a manufacturing cost reduction. The projected manufacturing piece and investment cost for the ULSAB are investigated using technical cost modeling. The results presented here examine the elements that contribute to the cost, including treatments for stamping, hydroforming, assembly and purchased parts.
Technical Paper

Hydroformed Structural Elements: An Economic Evaluation of the Technology

1998-02-23
980451
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.
Technical Paper

Evaluation of Tailor Welded Blanks Through Technical Cost Modeling

1998-02-23
980446
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.
Technical Paper

The Steel Unibody: The Application of Cost Analysis to Determine Cost Reduction Strategies

1998-02-01
981004
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.
Technical Paper

Compression Molded Sheet Molding Compound (SMC) for Automotive Exterior Body Panels: A Cost and Market Assessment

1997-02-24
970246
Automotive exterior body panels are a critical component of today's vehicle. They provide a surface for painting, offer the first line of defense against damage from accidents and the elements, and in most cases add to the overall stiffness of the vehicle. Despite small inroads from aluminum and polymer systems, steel remains the predominant body panel material. Of the alternatives, sheet molding compound (SMC) has been the most successful challenger. This paper examines the cost and market conditions affecting SMC today and in the near future. The impact on cost of SMC compression molding process improvements is assessed over a ten year period for a full body panel set. These results are compared to stamped steel as a function of annual production volume and other key factors. The result is a cost “crossover” point below which SMC has the lower cost.
Technical Paper

Making the PNGV Super Car a Reality with Carbon Fiber: Pragmatic Goal or Pipe Dream?

1996-02-01
960243
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.
Technical Paper

A Manufacturing Cost Analysis of Tube and Node Steel Spaceframes

1994-03-01
940657
The design and manufacture of today's automobile structure is dominated by a single approach: the stamping and spot welding of sheet steel. There are, however, a number of potential challengers to this steel unibody approach. These include a steel spaceframe, an aluminum unibody, an aluminum spaceframe, a composite monocoque, and hybrids of these types. The primary barriers to adopting these alternatives have been technical practicality and cost. This paper considers one of the alternative approaches -the steel spaceframe- and examines its cost for two potential design and manufacturing scenarios using a computer spreadsheet based technique called Technical Cost Modeling. Selected default assumptions -including annual production volume, piece count, and assembly rates- are then varied to assess their impact on overall cost. The manufacturing costs for a conventional steel unibody as well as several of the other alternatives are used as a baseline for comparison.
Technical Paper

Economic Criteria for Sensible Selection of Body Panel Materials

1991-02-01
910889
In order to determine the best way to evaluate materials selection from an economic standpoint, a discussion of conventional cost estimation is given versus a more precise technique, Technical Cost Modeling. Automotive body panels are used as an application for the costing techniques; conclusions about fabrication costs and parts consolidation are drawn with regard to these parts.
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