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In a drive to reduce overall vehicle weight, automotive manufacturers continue to look to aluminum alloys as a solution to provide complex lightweight structures. Precipitation hardened 6000 series aluminum alloys offer a mature commercially viable solution which may be produced using several different forming methods including the extrusion process. In some cases, aluminum products may be produced at a temper suitable for forming and later precipitation hardened to a temper with mechanical properties that meet structural requirements. Direct extrusion press capabilities continue to expand. In an effort to improve productivity, the runout lengths for presses have increased in an effort to reduce dead cycle time inherent to billet heating and loading. Long runouts, however, result in larger differences in pressure applied during extrusion. This pressure variation, confounded with differences in quenching and stretching, causes variation in the extruded product.

6061-O temper extruded rod may be used as feed stock in forming processes for automotive pressure vessel applications. Key parameters for forming are the strength and hardness of the material. The purpose of this paper was to reduce variation in hardness to achieve a process capability index of 1.33 or greater. Among the process steps affecting hardness, annealing is the most critical. Initially, the process showed unacceptable hardness variation. Initial anneal recipes called for a 4-hour soak at 775°F (413°C). Initial process capability for hardness was a Cpk of 1.12, with tensile strength readings very close to the upper specification limit. Initial temperature uniformity surveys of the anneal oven showed a large variation in temperature distribution, with some areas of the oven staying below 650°F (343°C). Initial improvement efforts focused on soak time.

O-rings are regularly utilized as a means of creating a seal between two components. Since the introduction of mini-concentric fuel pressure regulators, several issues have arisen related to assembly. In many cases, severe leaks are masked by lubricants used to aid in assembly. A lubricant is required which will not mask such leaks. The purpose of this study is to determine the impact on assembly between alcohol and oil based lubricants and to determine the optimum assembly parameters when using alcohol lubricants. Several variables were identified as being major contributors to the assembly process. A total of 6 variables were chosen to be examined as well as 2 noise factors. Each variable, or factor, was assigned several levels for this experiment. Several measurables were defined outputs from the experiment. To maximize the efficiency of testing, an orthogonal array was used to structure the experiment. An L18 orthogonal array was chosen composed of 72 trials.

Lean manufacturing has greatly changed the way many companies produce products. Lessons learned in lean manufacturing are being applied to many non-manufacturing situations including design, logistics, and transactional processes. Such tools can be applied to metallurgical laboratories which support daily production or design and development. Four key principles of lean management and nine tools are presented with specific examples demonstrating how these lean tools can be successfully applied to a metallurgical laboratory operations. These principles and tools have been successfully implemented by the author in a captive metallurgical laboratory over the last year resulting in reduced cycle time, higher productivity, less variation in analysis methods allowing for direct comparison of data over time, and improved quality.

Seals are commonly made by using o-rings in many liquid and gas filled system. Since the introduction of mini-concentric fuel pressure regulators mounted on fuel rails, issues have arisen related to assembly resulting in damage to the o-rings. The problem of damage o-rings can result in fuel leaks. The purpose of this study is to determine the optimum conditions in design/process to eliminate damage to the o-ring while maintaining sealability. A total of 14 variables were chosen to be examined in this study, 9 design related and 5 process related. To maximize the efficiency of testing, an orthogonal array was used to structure the experiment. After completing the study, assembly fixturing contributes 80% to successful assembly.

As many underhood products have shifted from metal to plastic designs over the last decade, often parts break during assembly due rough handling conditions and less than ideal manufacturing practices. In particular assemblies often crack during screw torquing at the mounting tabs. The goal of this study is to determine how different mounting tab designs compare in strength. Designs with an external rib on the perimeter of the mounting tab behave differently than designs without a complete or lacking an external rib on the perimeter of the mounting tab. A positive correlation was found between knit line cross-sectional area and mounting tab strength for designs with an external rib on the perimeter of the mounting tab. A positive correlation was found between tab thickness and mounting tab strength for designs lacking an external rib. Material type was found to impact mounting tab strength.

Often electrical components are encapsulated in a plastic material after assembly. The goal of this study is to determine what variables are most important in reducing potting variation and identify the key machine parameters which can be used to make adjustments to the potting process. To maximize the efficiency of testing, an L18 orthogonal array was used to structure an experiment. Hose temperature, orifice size, and pressure were found to be the most significant control factors studied in this experiment. Shifting from the initial settings for these factors to the recommended settings should increase the S/N of the potting process by 14.53db. Motor speed was found to be the most significant variable for adjusting the mean of the process. The noise factors induced in this study were found to be a significant source of variation. Filters can shift the mean potting material applied by 25% over their planned usage life. Moreover, new filters induce more variation than old filters.

Plastic underhood components often crack when fastened to mating components. The goal of this study is to determine what variables are most important with relation to this problem. To maximize the efficiency of testing, an L18 orthogonal array was used to structure the experiment. Experiments were conducted using a computer-controlled electric driven screwdriver and a manual torque wrench. Control factors were adjusted by using hardware as specified for each trial. The torque value at failure was recorded for all samples. The “larger the better” S/N equation was utilized for data analysis in this study. Optimizing the design and process was found to increase the S/N by 6.9dB when verified experimentally. Fastener washer thickness, joint fit-up, and screw setting speed contribute to the gain by 46%, 28%, and 27%, respectfully.

When commercializing squeeze casting and semi-solid metalworking processes, component producers looked to conventional die casting to identify potential defects and control component quality. Several defects were expected including cold shuts, cold flows, flash, drags, warping, and gas entrapment, just to name a few. Efforts were taken to avoid these defects. New defect types, however, have surfaced unique to these high integrity die casting processes. Contaminant veins and phase separation are presented. Although, squeeze casting and semi-solid metalworking have proven to be successful, component producers have been reluctant to report defects for fear of giving these emerging processes a bad reputation. Nonetheless, these defects must be understood to avoid future problems.

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.

Many manufacturers utilize statistical methods to control product characteristics during processing. Often traditional x charts are utilized. This method is appropriate when examining characteristics with one degree of freedom. For features with two or more degrees of freedom, traditional x charts may be misleading. Techniques for controlling characteristics with multiple degrees of freedom, however, have not been developed. The purpose of this paper is to present a method of statistical analysis using radial type charting techniques for characteristics with multiple degrees of freedom. Included in this paper is a detailed discussion of the steps to prepare and interpret radial type charts. These techniques are applied to true position measurements as a specific example.