Automotive Assembly Plant Research Articles

ASRS sizing for recreating automotive assembly sequences

Since a mixed model assembly line's efficiency depends on the sequence of jobs moving down the line, manufacturers spend considerable effort optimizing the sequence of jobs entering the plant. In automotive assembly plants however, repair loops and parallel stations scramble the sequence before it reaches the final assembly stage. Many automotive assembly plants use an automatic storage and retrieval system to revamp the scrambled sequence before final assembly. One plant even goes so far as to reconstruct the original sequence by completely undoing the sequence scrambling. We derive a relationship between the sequence scrambling information, the variety of model-colour configurations, and the size of the automatic storage and retrieval system needed to reconstruct the initial sequence. We enunciate this new ASRS sizing problem actually facing industry, show how to model it, present a solution approach, and demonstrate the approach on actual sequence scrambling data from an automotive assembly plant.

Inter-Rater Reliability for Hand Activity Level (HAL) and Force Metrics

Observational rating methods are used frequently in ergonomic job analysis because they are less costly and time consuming than other methods. The ACGIH recently published a threshold limit value (TLV) for repetitive work. This TLV suggests the use of one such observational method developed by Latko et al. (1997) for rating Hand Activity Level (HAL) and peak force. One criticism of Latko's method is the unknown reliability and consistency of the raters during the analysis process. Latko suggests the use of two or more trained observers to increase this consistency. This study analyzed 410 jobs at an automotive assembly plant using 2 observers recording initial and final ratings. A weighted kappa was calculated for the HAL and peak force before and after discussion. Before discussion, HAL reliability was rated as moderate and peak force as fair. After discussion, both HAL and peak force kappa values were rated as good.

A dynamic part-feeding system for an automotive assembly line

The part-feeding system at an assembly shop controls the feeding of parts from the warehouse to workstations of the assembly shop in accordance with the production of vehicles. The part-feeding system plays a crucial role in determining the level of the inventory and stockout rate at the automotive assembly line. In this study, we propose a dynamic part-feeding system for an automotive assembly plant which estimates the part consumption amounts dynamically considering the actual production progress and directs the feeding orders dynamically to feeders. The results of a simulation show that the proposed dynamic feeding system produces better results than a static feeding system.

An evolutionary approach to benchmarking

Introduces a framework for benchmarking organisations – “evolutionary benchmarking”. Discusses the concept and operation of the framework, along with its proposed advantages in aiding benchmarking. The benchmarking approach proposed utilises an evolutionary classification method called cladistics. Uses an example classification of automotive assembly plants to show how the proposed framework helps benchmarking in terms of: providing a framework for representing benchmarking information; enhancing the quality and validity of the information according to the classification rules of parsimony, congruence and homology; and providing a comparison that indicates how the practices should be adopted. This framework is considered to be useful to researchers who study benchmarking methodologies and those that categorise the findings of benchmarking studies.

A fluctuating plume dispersion model for the prediction of odour-impact frequencies from continuous stationary sources

A fluctuating plume dispersion model has been developed to facilitate the prediction of odour-impact frequencies in the communities surrounding elevated point sources. The model was used to predict the frequencies of occurrence of odours of various magnitudes for 1 h periods. In addition, the model predicted the maximum odour level. The model was tested with an extensive set of data collected in the residential areas surrounding the paint shop of an automotive assembly plant. Most of the perceived odours in the vicinity of the 64, 46 m high stacks ranged between 2 and 7 odour units and generally persisted for less than 30 s. Ninety-eight different field determinations of odour impact frequencies within 1 km of the plant were conducted during the course of the study. To simplify evaluation, the frequencies of occurrence of different odour levels were summed to give the total frequency of occurrence of all readily detectable (>2 OU) odours. The model provided excellent simulation of the total frequencies of occurrence where the odour was frequent (i.e . readily detectable more than 30% of the time). At lower frequencies of occurrence the model prediction was poor. The stability class did not seem to affect the model's ability to predict field frequency values. However, the model provided excellent predictions of the maximum odour levels without being sensitive to either stability class or distance from the source. Ninety-five percent of the predicted maximum values were within a factor of two of the measured field maximum values.

Simplified Automotive Wastewater Sludge Dewatering and Drying

Simplified Automotive Wastewater Sludge Dewatering and DryingIn 1997, DaimlerChrysler Corporation announced plans to construct a new automotive assembly plant in Toledo, OH to replace their aging Toledo (Parkway) Assembly Plant. From the concept stage of the project, the goal of the wastewater treatment facility for the Toledo North Assembly Plant (TNAP) was to integrate environmental aspects of the operation with sound business decisions to reduce the...Author(s)D. J. JechuraA.L. JoyceD. E. BentleySourceProceedings of the Water Environment FederationSubjectSession 78 - Industrial Issues and Treatment Technology Symposium: Automotive and Metals WastewaterDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2001ISSN1938-6478SICI1938-6478(20010101)2001:9L.583;1-DOI10.2175/193864701790861613Volume / Issue2001 / 9Content sourceWEFTECFirst / last page(s)583 - 594Copyright2001Word count108

Microfiltration for Second-Stage Softening Provides Many Benefits to an Automotive Assembly Plant in Mexico

Microfiltration for Second-Stage Softening Provides Many Benefits to an Automotive Assembly Plant in Mexico

A fuzzy system for automotive fault diagnosis: fast rule generation and self-tuning

This paper describes a fuzzy model that learns automotive diagnostic knowledge through machine learning techniques. The fuzzy model contains the algorithms for automatically generating fuzzy rules and optimizing fuzzy membership functions. The fuzzy model has been implemented to detect a vacuum leak in the electronic engine controller (EEC) as part of the end-of-line test at automotive assembly plants. The implemented system has been tested extensively, and its performance is presented.

Analysis of Various Automotive Body Assembly System Configurations with Respect to Reliability, Quality, and Productivity

We first develop techniques for identifying the configuration of a body assembly system. These techniques are essential because of the increasingly sophisticated hardware adopted in modern automotive assembly plants. Then we use these techniques to benchmark the system configurations of three different automotive body assembly lines. Then we analyze the system reliability of serial, parallel, and parallel-lines and serial-groups systems. Some results are the following: with constant machine reliability, an assembly system could become more reliable if it has more possible paths of material flow. A parallel system configuration has the maximum system redundancy, and its reliability is highest. A serial system configuration has only one path of material flow, so system shutdown cannot be avoided if any of its stations fail. A serial-groups system has a slightly higher reliability than a parallel-lines system has, and both of them are much more reliable than a serial system. If we want to increase the reliability of some critical processes, we can combine several tasks and then duplicate the lines to form a parallel system with not-so-expensive machines. We then analyze the same four configurations for their expected production and present these results also. The relationships between sheet metal assembly quality and different assembly system configurations are investigated. Four different assembly system configurations (serial, parallel, and parallel-lines and serial-groups system configurations) are designed to produce the same sheet metal product. With the same sources of variation, we simulate how the dimensional variation of assembled sheet metal parts is affected by different system configurations. Mechanistic variation is used to analyze the variation stack-up of deformable sheet metal part assemblies. From the simulation results, we find that the more material-flow paths an assembly-system had, the distribution of its products' quality is wider. Also, the parts processed through more serial fixtures may have a higher mean deviation.

Transition and change during the implementation of a computer-based manufacturing process planning system: an analysis using the equity implementation model

Implementing changes in technologies, systems, work practices and organizational structures is vitally important for the survival of organizations in today's competitive environments. However, introducing changes in organizations is not easy. Employees often resist changes. This paper presents a case study of the implementation of a computer-based manufacturing process planning system in an automotive assembly plant. The paper employs an equity implementation model to understand resistance to the system by zone supervisors and quick acceptance by plant engineers, two major employee groups who were affected by this change. Factors affecting employee reactions to the change are identified and analyzed on the basis of the equity implementation model. The paper concludes that the equity implementation model provides a useful framework for understanding and explaining resistance and acceptance behavior of employees. The model can also be useful in assessing the job-related impacts of a system or technology implementation. The paper also discusses suggestions for implementers in developing successful change implementation strategies.

Automotive industry looks for lean production

Reviews new automotive assembly plants in Europe. Outlines the lean production techniques Daimler‐Benz is using for the new Mercedes A‐Class. Describes the flexible NedCar facility which makes Volvos and Mitsubishis on the same production line. Explains the benefits Skoda has obtained by integrating suppliers into its new assembly facility for the Octavia.

Feasibility of a Computer Downtime Recording System

This paper describes the development of a computerised downtime recording system for an automotive assembly plant. It introduces the nature of the recording system environment at a large commercial van assembly plant and describes the system developed in terms of, characteristics and usability. The application analysis focuses on the user-computer interface.

In-plant material buffer sizes for pull system and level-material-shipping environments in the automotive industry

Traditionally automotive assembly plants operate with at least two weeks of frozen vehicle orders enabling them to calculate the amount of material needed for the next two weeks. Implementing a pull system between the plant and its customers, and level-material-shipping between the plant and its suppliers, changes the amount of material buffer needed within the assembly plant. The pull system eliminates the frozen vehicle-order schedule, without which plants cannot calculate the material needed, but must use inventory to buffer the line from random demand. Level-material-shipping, a just-in-time principle that provides suppliers with a constant shipping schedule, forces plants to use material inventory to buffer the line from un-level demand for parts resulting from un-level production or an un-level model mix. We model these effects to derive formulas for the buffer needed to provide a given service level in the face of demand variability, un-level production, and un-level model-mix.

The Road to “Root Cause”: Shop-Floor Problem-Solving at Three Auto Assembly Plants

This paper uses case studies of shop-floor problem-solving at three automotive assembly plants to examine organizational influences on process quality improvement. Three complex quality problems—water leaks, paint defects, and electrical defects—were chosen because they are universally found in assembly plants, have multiple sources, and can only be resolved with high levels of interaction and coordination among individuals in multiple departments or functional groups. The case studies focus particularly on the early stages of the problem-solving process—problem definition, problem analysis, and the generation of solutions—emphasizing how each plant tries to identify the “root cause” of defects. The paper then explores consistencies and contrasts within and across the three cases to analyze the factors underlying effective shop-floor problem-solving. Central to this analysis is the idea that successful process quality improvement depends heavily on how the organization influences the cognitive processes of its members. Problem-solving processes benefit from rich data that capture multiple perspectives on a problem, problem categories that are “fuzzy”, and organizational structures that facilitate the development of a common language for discussing problems. Also, when problems are framed as opportunities for learning, the combination of positive attributions that boost motivation and the suppression of threat effects can improve the effectiveness of improvement activities. Finally, when process standardization is understood as marking the beginning (and not the end) of further improvement efforts, the normal inertial tendencies of organizations with respect to adaptive learning can be partially overcome.

Organizational Influences on Process Quality Improvement: Shop-Floor Problem-Solving in Auto Assembly Plants

This paper uses case studies of shop-floor problem-solving at three automotive assembly plants to examine organizational influences on process quality improvement. Three complex quality problems - water leaks, paint defects, and electrical defects - were chosen because they are universally found in assembly plants, have multiple sources, and can only be resolved with high levels of interaction and coordination among individuals in multiple departments or functional groups. The case studies focus particularly on the early stages of the problem-solving process: problem definition, problem analysis, and the generation of solutions. The paper then explores consistencies and contrasts within and across the three cases to analyze the factors underlying effective shop-floor problem-solving. Central to this analysis is the idea that successful process quality improvement depends heavily on how the organization influences the cognitive processes of its members. Problem-solving processes benefit from rich data that capture multiple perspectives on a problem; problem categories that are fuzzy; and organizational structures that facilitate the development of a common language for discussing problems. Also, when problems are framed as opportunities for learning, the combination of positive attributions that boost motivation and the suppression of threat effects can improve the effectiveness of improvement activities. Finally, when process standardization is understood as marking the beginning (and not the end) of further improvement efforts, the normal inertial tendencies of organizations with respect to adaptive learning can be partially overcome.

Scheduling Preventive Overtime: A New Approach for the Automotive Industry

Because over $2 billion was spent on overtime at US and Canadian automotive final assembly plants in 1994, identifying ways to reduce overtime can have a significant effect on the cost of producing...

Ocular hazards of industrial spot welding.

Any welding process is perceived to be a radiation hazard to the eye. Site visits were made to an automotive assembly plant to assess the levels of optical radiation and other hazards on the production line. Measurements were taken with a scanning spectro-radiometer and optical power and energy meters at operating working distances at spot welding stations where nonrobotic procedures were performed. Ultraviolet (UV) irradiance levels produced while spot welding with electrodes operating at 10 to 15 kA and 10 to 20 V were several orders of magnitude below recommended safety limits for industrial exposure. Flashes were rich in visible light and infrared (IR) radiation, but not at hazardous levels. The principal hazards in manual spot welding with high-current electrodes are high-speed droplets of molten metal produced by the process. These are easily defended against by wraparound polycarbonate eye shields.

Product Variety and Manufacturing Performance: Evidence from the International Automotive Assembly Plant Study

This paper examines the effect of product variety on manufacturing performance, defined here as total labor productivity and consumer-perceived product quality. Using data from the International Motor Vehicle Program (M.I.T.) study of 70 assembly plants worldwide, the paper examines three dimensions of product variety, at fundamental, peripheral, and intermediate levels. The international sample reveals great variation in the distribution of each type of product variety in different regions, reflecting in part different strategies for variety. Furthermore, the impact of different kinds of product variety on performance varies, and is generally much less than the conventional manufacturing wisdom would predict. However, an intermediate type of product variety, here called parts complexity, was found to have a persistent negative impact on productivity. Finally, the study provides partial support for the hypothesis that management policies, in both operations and human resource areas, can facilitate the absorption of higher levels of product variety, i.e. that “lean production” plants are capable of handling higher levels of product variety with less adverse effect on total labor productivity than traditional “mass production” plants.

Quantifying the advantages of production quota flexibility in the automotive industry

Manufacturers use production quotas to smooth and synchronize production. We use a Markov chain to quantify the effect of quota flexibility on overtime and inventory costs. This quantification allows us to trade off these costs to find the optimal amount of quota flexibility. We define quota flexibility as the permitted amount and duration of deviations from the cumulative quota. We specifically analyse the cost savings as a function of the maximum allowed deviation amount from the cumulative quota for four policies. These example policies are the four permutations of two factors: whether or not backlogging is permitted; and whether or not actual production and the quota must be reconciled weekly. We apply the model to three automotive assembly plants and conclude that permitting modest flexibility in production quotas (of ⩾ 1 h of production) significantly reduces total cost.

Shape Characteristics of Cost Curves Involving Multiple Shifts in Automotive Assembly Plants

ABSTRACT Based on a typical automotive assembly plant in today's environment, this analysis provides insight into the marginal cost curves facing industry. Because of employment guarantee provisions of the labor contract, the short-term marginal cost curve is not U-shaped, increasing, nor even convex. A consequence of this complicated shape is that there may be more than one point where marginal cost equals marginal revenue, thus requiring the firm to evaluate each such point to find its profit maximizing production level.