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Technical Paper

Dimensional Quality Control of Repeated Molded Polymer Battery Cell Housings in Automotive Energy Systems

Current manufacture of alternative energy sources for automobiles, such as fuel cells and lithium-ion batteries, uses repeating energy modules to achieve targeted balances of power and weight for varying types of vehicles. Specifically for lithium-ion batteries, tens to hundreds of identical plastic parts are assembled in a repeating fashion; this assembly of parts requires complex dimensional planning and high degrees of quality control. This paper will address the aspects of dimensional quality for repeated, injection molded thermoplastic battery components and will include the following: First, dimensional variation associated with thermoplastic components is considered. Sources of variation include the injection molding process, tooling or mold, lot-to-lot material differences, and varying types of environmental exposure. Second, mold tuning and cavity matching between molds for multi-cavity production will be analyzed.
Technical Paper

Innovative Robust Solutions for Lean Manufacturing in Automotive Assembly Processes

The article presents an innovative approach to the implementation of a robust design optimization solution in an automobiles assembly process. The approach of the entire project is specific to the 6 Sigma optimization process, by applying the DMAIC cycle integrated in a robust engineering approach for rendering lean the final product assembly process. According to the improvement cycle, the aspects specific for such a process are presented sequentially starting with the “Define” phase for presenting the encountered problem and continuing with the presentation of the scope of the project and its objectives. The “Improvement” cycle phase is applied by the analysis of the monitored 6 Sigma metrics (defined during the previous “Measure” phase and the cause and effect analysis, done during a brainstorming meeting developed during the “Analyze” phase). There follows a proposal for the innovative robust solution by which the assembly process is optimized.
Technical Paper

Advanced Manufacturing Technologies for General Assembly

The current challenges of the automotive industry illustrate the importance of a clear picture for an innovative, next generation General Assembly, supported by a roadmap for future oriented advanced manufacturing technologies. Based on the profound analysis of the existing technology portfolio a vision of a desired state of a future oriented lean assembly plant is developed. This paper defines the gap for needed technology, explains the criteria for future assembly technology and describes the roadmaps to accomplish the vision of next generation General Assembly. The strategies are explained and some projects will be shown as example for the roadmaps to increase the competitiveness. The current economical crisis led to a drop of production volume up to 50%. This disclosed that current assembly plants are not set up for volume flexibility. Line speed changes require massive changes in process and assembly operations.
Technical Paper

Prototypes Assembling Management Supported by Key Performance Indicators

A methodology for planning, assembling follow-up and reporting performance indicators is discussed in this paper as a case in the prototypes management at the Mercedes-Benz Brazil. In the planning module of this tool, the resources allocation task is supported by lessons learned from similar projects done previously in order to achieve the project timeline. Additionally, an assembling follow-up module can be used to manually update each project status and employed resources. The planned schedule and the assembling status are automatically compared generating performance indicators in a weekly report. Based on these results, contingency mechanisms, resources relocations and/or a new ranking of projects priorities can be supported by reliable data, avoiding financial losses or delivering delays.
Technical Paper

Self-Tapping Fasteners for Lightweight Designs

Abstract As automotive technology rapidly provides advances in lighter weight designs and materials, the technology to fasten and join them must keep pace. This paper will explore two uniquely different fastening technologies that are being used to address some of today's demanding application challenges in plastics and thin steel and aluminum sheet. These are two areas of application that have historically provided few good options for designers, especially as they attempt to push the envelope with progressive, light weight designs. The first technology is self- tapping screws for plastics that, although not new, are now evolving to enable smaller bosses and shorter thread engagements, and incorporate light weight design options. Although dependent on the demands of the application, these screws can be produced in both steel and, now, lighter weight materials such as aluminum and plastic.
Technical Paper

Fastener Coating Change for Efficient Functional Performance in Automotive Application

Fasteners performance on account of rust is not consistent and conductivity is a concern. A surface coat is applied on fasteners to provide corrosion protection, i.e., protection against rust. When a metal comes in contact with Oxygen present in the air, it gets corroded. So, an extra protective layer is required to prevent the contact of metal with air, hence preventing corrosion. However, surface coating peel-off is a persistent problem observed while assembly of fasteners, which leads to impetuous rusting of parts. So, repeated use of fasteners in service life becomes a matter of concern. At the same time, it is important to provide conductive surface coating to fasteners used in fuel filler area. When a human body comes in contact with fuel filler area, it is necessary to discharge the static electricity of humans, in order to avoid explosion, due to generation of spark in presence of fuel fumes.
Technical Paper

Use of Single Point Interface Measures for Characterization of Attachments

Often components or subsystems are attached to other systems through multiple fasteners at multiple locations. Examples may include things like compressors, alternators, engine cradles, powertrain mounting systems, suspension systems, body structures or almost any other interface between components or subsystems. Often during early design stages, alternative component or subsystem configurations are being considered that can have very different interface characteristics, such as alternators with different number of mounting fasteners, or suspension systems with different number of body structure interface attachments. Given these different mounting configurations, it can be difficult to meaningfully compare the interface performance of the two components or subsystems.
Technical Paper

Surface Mineralization as an Alternative to Cadmium Plating and Hexavalent Chromate Treatment for Corrosion Protection

The purpose of this paper is to examine the use of a surface mineralization process for general corrosion protection. More specifically, this paper describes the use of surface mineralization (SM) as a non-hazardous and environmentally benign alternative to cadmium plating and hexavalent chromate treatment for protecting fasteners from corrosion in off highway applications. An engineered surface is founded on a mineral-based product that forms a thin metal silicate surface fully involving the substrate metal. Completed laboratory cyclic testing of SM treated fasteners compared with cadmium plated and hexavalent-chromate treated fasteners to 180 cycles using the GM 9540P protocol have demonstrated a significant increase in corrosion resistance of components protected by the SM process.
Technical Paper

Effect of Number of Measurement Locations in the Implementation of Iterative Wavenumber Fitting for Viscoelastically Damped Structures

The work presented here is an experimentally-based parametric study of a layered viscoelastically-damped system containing intermediate structural fasteners. The effect of fastener preload, fastener location and the number of fasteners on the loss factor are examined. The loss factor is found to change by as much as 22% with change in some of these parameters. Two different approaches are used to measure loss factor. The first method uses the internal algorithm from a signal analyzer. The second method is an iterative algorithm that estimates the complex wavenumber, which is then used to find the damping loss factor. An advantage of the latter technique is the ability to measure loss factor over a range of frequencies. This research also investigates the effect of the number of measurement positions on the accuracy of loss factor. It is shown that the accuracy has a strong dependence on the number of measurement locations, particularly at low frequencies.
Technical Paper

Polyamide Intake Manifold Shell Bonding

The purpose of this paper is to introduce a new potential assembly technology for polyamide intake manifold manufacture. In this paper we will outline the current assembly methods, introduce adhesive bonding as an alternative assembly method, and demonstrate a validation methodology for this new technology. To demonstrate the viability of this new technology, a design of experiments was conducted and the results of which shall be shared.
Technical Paper

Accounting for Thermal and Gravity Force Effects on Automotive Components Using 3D Simulation Software

Abstract The effects of thermal expansion and gravity on assembly processes in automotive manufacturing can and often do cause unexpected variation. Not only do these effects cause assembly issues, they can also create non-conformance and warranty problems later in the product lifecycle. Using 3D CAD models, advances in simulation allow engineers to design out these influences through a combination of tooling, process and tolerance changes to reduce costs. This whitepaper examines the process of simulating the effect of both thermal expansion and gravity on automotive structures. Using real life examples, a number of solutions were determined and tested in a simulated environment to reduce product variation and account for unavoidable environmental variation.
Technical Paper

Self-Loosening of Three Similar Bolted Joint Designs Using Finite Element Analysis

Abstract Self-loosening of bolted connections is a crucial failure mode for joints under transverse dynamic load. For some years, three dimensional finite element analysis has been enabled for avoiding experimental investigations of self-loosening. The aim of this paper is to emphasize the effect of joint design on the self-loosening of bolted connections, which is important for product development in early design stage. Joints consisting of internally threaded nut components are often heavier and stiffer as compared with light weight designs consisting of a separate nut. The difference of self-loosening is significant between arrangements with nut thread component and separate nut, although the design versions only contain slight modifications. Hence it is necessary to evaluate the effect of light weight design on self-loosening.
Technical Paper

Wheels and Tires Assembling Case Study

Abstract This paper makes an analysis of problems encountered in assembling components from automotive vehicles. It shows wheel and tires assembling cases of an automaker that applies lean manufacturing concepts in the production process. This study not only makes the analysis from the best way to apply the methodology to seek for the root cause, but also uses methodology to identify containment measures, defining robust solutions capable of preventing the incidence of similar problems. This methodology can be applied to solving problems of any production process, even outside of the automotive industry
Technical Paper

“U” Bolt Torque Influence over Leaf Springs

Abstract ”U” bolts are fixing elements and they are used to clamp an elastic joint. From the past, they still looking as an old design and unfortunately, suspension engineers are not specialists in fasteners and elastic joints. That is why we will show important assumptions and concepts to design and specifications this clamp element “U” bolt and its influence over leaf-springs. Currently, “U” bolt is used to clamp an elastic or elastic-plastic joint of heavy duty suspension, formed by leaf-spring, axle, spring pad, “U” bolt plate. This kind of suspension is typically used to trucks, buses and trailers. We are wondering, which one important assumption that an engineer must be careful when designs a new suspension changing from old designs to an updated technology. We provide a theoretical analysis and a FEA analysis to compare torque efficacy x leaf-spring reactions and what are effects this relationship can cause in a suspension.
Technical Paper

Innovative Production System Based on Auto-Assembly Cells

Abstract Today, conventional requests for automation and modern requests for flexibility in handling product diversity and changes in production volume regarding assembly operation are increasing. In order to satisfy those, the “Innovative Automation Cell” (Refer to Figure 1) has been proposed as an innovative assembly production system in lieu of an assembly line operation, which has been continuing with the use of automatic conveyance. Furthermore, technical developments were implemented, such as “Real-time Position Attitude Correction Technology” and “High-speed Emergency Recovery System”, as well as “Assembly Operation Support System”, to make an easy system for an operator, so as to minimize reduction of run rate in mass production practices. This article addresses the concept of the “Innovative Automation Cell”, the details of the developed technology, the effects of introduction to mass production, and future issues.
Technical Paper

Integrated Manufacturing - Assembly Line Consolidation

Companies are often faced with periods of fluctuating product demand that can make it difficult to maximize the usage of their capacity and resources. This makes it challenging to realize potential profit and can even have detrimental effects on the bottom line. Developing flexibility strategies to react to fluctuations in demand allows a manufacturer to dynamically adjust capacity and resources to keep costs under control. This project was pursued at a diesel engine manufacturer for two older product lines experiencing consistently declining volumes. The volumes were declining due to this company releasing newer products in the market, and the current economic downturn. There was also an expectation to eventually phase out these two engines after approximately five years. A project team was formed to address these challenges starting with defining the project scope, setting up the team and a cross-functional project structure, and developing work packages with a master timeline.
Technical Paper

Simulating Complex Automotive Assembly Tasks using the HUMOSIM Framework

Efficient methods for simulating operators performing part handling tasks in manufacturing plants are needed. The simulation of part handling motions is an important step towards the implementation of virtual manufacturing for the purpose of improving worker productivity and reducing injuries in the workplace. However, industrial assembly tasks are often complex and involve multiple interactions between workers and their environment. The purpose of this paper is to present a series of industrial simulations using the Human Motion Simulation Framework developed at the University of Michigan. Three automotive assembly operations spanning scenarios, such as small and large parts, tool use, walking, re-grasping, reaching inside a vehicle, etc. were selected.
Technical Paper

Anthropometry for a North American Manufacturing Population

Digital Human Models are used extensively in virtual manufacturing to evaluate hand clearance and reach. Spatial assessments of accommodation are typically conducted using digital human models representative of the manufacturing population. Unfortunately, these models are often based on anthropometry gathered from sources that are not representative of the actual target worker population. For example, the size and shape might be based on data from the U.S. military, which differs in .fitness, age, and race distributions from the typical automotive manufacturing population. Ford ergonomists traced errors in accommodation predictions to these inaccurate representations. Using a recently developed statistical methodology incorporating principal components analysis, the anthropometry of the target worker population was synthesized. Using these new data, Ford updated the anthropometry of their digital human models to reflect changes due to secular trends in the U.S.
Technical Paper

The Evaluation of Hose Insertion Tasks Using Digital Human Models

The use of digital human models (DHM) to perform geometric evaluations of hand clearances and reach zones has become common practice at Ford Motor Company. Moreover, DHMs have also been used for performing strength evaluations to ensure ergonomically acceptable jobs. A process called Hose Connections Acceptability Ratings (HCAR) was developed to establish insertion force targets in the early phases of product design. Once targets are set, design and release engineers provide design intent data to achieve sign off from manufacturing engineering. The process is complete when the hose efforts are confirmed at physical part validation build events.
Journal Article

Digital Human Modeling Simulation Results and Their Outcomes in Reality: A Comparative Study within Manual Assembly of Automobiles

The objective of this study was to examine to what extent ergonomics simulations of manual assembly tasks correctly predict the real outcomes in automotive assembly plants, and if recommended measures originating from ergonomics simulations are considered. 155 ergonomics simulation cases done by nine simulation engineers at Volvo Car Corporation in Gothenburg were used in the study. The evaluations of the ergonomics conditions in reality of the cases were done by six professional ergonomists working in the company. The results show that digital human modelling tools are useful for providing designs for standing and unconstrained working postures as well as for the design of various auxiliary devices and their needed space for movements. The study also identifies areas that require additional development in order to improve the digital human modelling tools’ ability to correctly predict a work task's real outcome.