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A process to achieve vehicle system level NVH objectives using CAE simulation tools is discussed. Issues of modeling methodology, already covered adequately in the literature, are less emphasized so that the paper can focus on the application of a process that encompasses objective setting, design synthesis, and performance achievement using simulation predictions. A reference simulation model establishes correlation levels and modeling methods that are applied to future predictions. The new model, called a “Digital Mule”, is an early new product “design intent” simulation used to arrive at subsystem goals to meet the vehicle level NVH objectives. Subsystem goals are established at discrete noise paths where structure borne noise enters the body subsystem. The process also includes setting limits on the excitation sources, such as suspension and powertrain.

Passengers' frequent requests are for less Noise, Vibration and Harshness (NVH) in the vehicle compartment. This and the reduction of noise and vibration levels from major sources like the engine necessitate better performance of other sources of noise and vibrations in a vehicle. Some of these sources are the hydraulic circuits including the power steering system. Fluid pulses or pressure ripples, generated typically by a pump, become excitation forces to the structure of a vehicle or the steering gear and represent a considerable source of discomfort to the vehicle passengers. Current power steering technology attenuates this ripple along the pressure line connecting the pump to the steering gear. Finding the optimum design configuration for the components (hose, tuner, tube, and others) has been a matter of experience-based trial and error. This paper is a part of a program to simulate and optimize fluid borne noise in hydraulic circuits.

A tuning cable and hose device, i.e. a flexible metal tuning cable placed coaxially inside a section of hose, is usually used in power steering hydraulic circuits to reduce pressure pulsations in the circuits. To evaluate the fluidborne noise attenuation characteristics of tuning cable and hose devices correctly, a new evaluation method, based on the experimental determination of transmission loss of the tuning cables and hoses, is proposed here. The effectiveness of the method and test system are confirmed. The results obtained are valuable for design optimization and theoretical modeling of hydraulic power steering systems and other similar hydraulic systems.

Controlling the torsional vibrations of an internal combustion engine has been a subject since the early 1900's. Some of the first torsional vibration damper patents were issued as early as the 1930s (Stamm and Knohl, 1931; Lee, 1933). These dampers were primarily used on the crankshaft. As engine technology has grown so has the need to control torsional vibrations in other areas, particularly camshafts. Overhead camshaft technology has improved the efficiencies and emissions for todays engine applications. As refinement progresses in system responsiveness a practical solution in controlling these vibration forces and anomalies can be achieved with an elastomeric camshaft torsional damper. Testing has shown that system refinement and durability is realized with the application of the camshaft damper technology in certain SOHC and DOHC engines.

This session keynote paper presents a framework for designing and deploying production systems. The framework enables the communication and determination of objectives and design solutions from the highest level to the lowest level of a manufacturing enterprise. The design methodology ensures that the physical implementation, called Design Parameters (DPs), meets the objectives or Functional Requirements (FRs) of the production system design. This paper presents a revolutionary approach to determine the objectives and the implementation of a “lean” production system design for a manufacturing business as guided by the design axiom of independence.

This paper presents an Axiomatic Design framework for manufacturing system design and illustrates how lean cellular manufacturing can achieve volume flexibility. Axiomatic Design creates a design framework by mapping the functional requirements of a system to specific design parameters. Volume flexibility is often neglected as a requirement of manufacturing systems. Very few industries are fortunate enough to experience stable or predictable product demand. In reality, demand is often volatile and uncertain. It is important that manufacturing system designers are aware of manufacturing system types which can accommodate volume flexibility and follow a structured design methodology that assures that all requirements are met by the system.

The Timken Company's Faircrest Steel Plant has numerous automated control systems. The Raw Material Handling System and a grinder application on the Billet Conditioning system needed upgrading; however, to control costs the upgrades had to use the existing I/O. The overall functionality of these two systems is vastly different. Soft control packages proved capable of interfacing with the existing I/O, satisfied the functional needs of the systems, and enhanced the overall functionality of the systems.

The design of a new production system requires a framework for ensuring that high level system objectives are satisfied by all subsystems and components. Since production system design is a multidisciplinary activity that extends beyond the boundary of any single company, a means to communicate these objectives and provide understanding to outside vendors and suppliers is also important. This paper describes both the framework and guidelines used to design a production system for a recently developed automotive compressor. The actual production system that was designed is given along with specific system and equipment examples originating from the design guidelines. These examples also show how the low level design decisions satisfied high-level system requirements.

Process Failure Mode and Effects Analysis (FMEA) has become an important tool for identifying potential weaknesses in manufacturing processes. The Automotive Industry Action Group (AIAG) has published guidelines that help ensure that Process FMEAs are developed and interpreted in a consistent fashion. These guidelines, while very helpful, are still open to broad interpretation, and need further development and improvement, especially in the area of detection rankings. The current detection ranking criteria are very subjective, difficult to apply in a consistent fashion, and can easily be used to skew Risk Priority Number results. This paper will describe revisions to the guidelines for detection rankings that have been successfully used in developing Process FMEAs for automotive manufacturing processes.

The paper focuses on various important decisions of verification and testing plans of the product during its design and production stages. In most of the product and process development projects, decisions on verification and testing are ad-hoc or based on traditions. Such decisions never guarantee the performance of the product as planned, during its whole life cycle. We propose an analytical approach to provide the concrete base for such crucial decisions of verification planning. Accordingly, a mathematical model is presented. Also, a case study of an automotive Electro-mechanical product is included to illustrate the application of the model.

Structured problem solving methods are utilized in the automotive industry for the efficient resolution of quality issues in manufacturing. Several problem solving methodologies have been developed, each with the same basic philosophy to prevent problem reoccurrence. Numerous barriers inhibit the effectiveness of problem solving. Although some tactical barriers may be overcome by training personnel, the majority of barriers are strategic or cultural in nature. Barriers at these two levels can only be removed by management level personnel. Management must shift its focus from firefighting to problem prevention. This shift can only be realized if problem prevention is addressed during design.

Weldability study has been performed on Polypropylene (PP) and PC/ABS samples to investigate how the paint layer along the weld joint affects the vibration weldability. The plastic used for this study were PP representing semicrystalline thermoplastics and PC/ABS representing amorphous thermoplastics. Both resins were molded to generate sample plaques for the study. Design of Experiment (DOE) studies were initially conducted with unpainted plaques and then repeated with the painted plaques for comparison. Optimal welding parameters were determined through DOE and the maximum weld strength under optimized welding conditions were determined and compared. Following each DOE, a regression analysis, using the weld strength as a response, was performed.

An experimental evaluation to systematically study a hot air cold stake joining process was conducted with injection molded samples. Twelve material combinations consisting of six stud plate materials were matched with two hole plate materials (GDT 6400 and 18% talc filled PP). Seven stud designs with variations in size and geometry were used for each material combination. A proper heating temperature was first determined by heat characterization trials. Different heating times and stake heights were studied in the staking experiments. Pull tests were conducted to determine the strength of the joints and their failure mode. Results showed that material characteristics, material combinations, and process parameters all could contribute to variations in pull strength and different failure modes.

In automotive assembly facilities worldwide, many critical vehicle systems such as brakes, power steering, radiator, and air conditioning require the appropriate fluid to function. In order to insure that these critical vehicle systems receive the correct amount of properly treated fluid, automotive manufacturers employ a method called Evacuation and Fill. Due to their closed-loop design, many critical vehicle systems must be first exposed to vacuum prior to being flooded with fluid. Only after the evacuation and fill process is complete will the critical vehicle system be able to perform as specified. It has long been thought, but never proven, that humidity and entrenched fluid were major hindrances to the Evacuation and Fill process. Consequently, Ford Motor Company Advanced Manufacturing Technology Development, Sandalwood Enterprises, Kettering University, and Dominion Tool & Die conducted a detailed project on this subject.

A design framework based on the principles of lean manufacturing and axiomatic design was used as a guideline for designing an automotive component manufacturing system. A brief overview of this design decomposition is given to review its structure and usefulness. Examples are examined to demonstrate how this design framework was applied to the design of a gear manufacturing system. These examples demonstrate the impact that low-level design decisions can have on high-level system objectives and the need for a systems-thinking approach in manufacturing system design. Results are presented to show the estimated performance improvements resulting from the new system design.

A simulation study was undertaken to help design a material delivery system to support lean manufacturing in an automotive body shop. Since this was a greenfield facility, simulation analysis was employed in the very early design phase of the system to determine and quantify the limiting parameters of the proposed lean material delivery system. The simulation analysis evolved with the changes in the design parameters and assumptions of the facility. The updated information from the simulation model helped the designers to evaluate alternate concepts and understand some parameters better such as, traffic congestion, manpower, and storage area requirement.

Plastics are largely regarded as commodity materials. However, they differ considerably from the materials which we became acquainted with during our college education. Although one can proceed to design plastic components and manufacture them without seriously considering a training program, the consequences can be substantial sacrifices to quality, development cost, part cost, and time to market, as well as adding a great deal of unnecessary stress to the workplace. This presentation explains why plastics are different and recommends a training curriculum that should be a part of strategic planning.

The engineering community is becoming increasingly aware of the significant benefits of performing error proofing on product and tooling designs. If a part or tooling can be designed or redesigned to allow for one-way assembly, the option of incorrect assembly at the plant is eliminated, making the process more robust. The goal of the error proofing exercise is to reduce operator decisions, eliminate misbuilds, and improve quality. Through participation in this type of exercise, all key stakeholders, including product, process, tooling, and production personnel, have greater opportunity to identify, prevent, and resolve potential production issues well in advance of launch.

The linked cell system gives both reduced cost and volume flexibility. The characteristics of the linked cell system are a consequence of decoupling the operators from the machines, using standard work in process between the cells and by integrating the information system with the cell and system design. By decoupling the operators from the machines the capacity can be increased/decreased in small increments by using more or fewer operators in the cell. The information system is integrated with the linked cell design by the use of a Heijunka box. The Heijunka is used to level production and to initiate the pace of production as a result of pulling withdrawal kanban at a standard time interval. This standard time interval is called the pitch of production. The kanban cards give information about what to produce, when to produce, when to make changeovers but they also give information to control the material replenishment.

Lean production has greatly influenced the way manufacturing systems should be designed. One important aspect of lean production is takt time. Takt time relates customer demand to available production time and is used to pace the production. This paper applies the manufacturing system design and deployment framework to describe the impact of takt time on both the design and the operation of a manufacturing system. The goal of this paper is to illustrate the relevant relationships of takt time to overall system design.