Assembly line design methodologies have been extensively researched during the past decades. Various definitions of problems have been established together with different approaches as to the way ...they are solved. However, in the automotive industry, most companies still use simple tools and methods for the solution of these problems. There can be spreadsheet applications and simulation tools that do not provide actual decision support, and are limited to assisting engineers in distributing the processes to different work centres. Furthermore, most approaches take into account only a few goals and constraints, by providing either non-realistic solutions or no decision support to production engineers, beyond the distribution of processes. This paper proposes an assembly design algorithm that considers both time and cost parameters for the generation of different line alternatives; the algorithm, taking into account industrial requirements, considers multiple products of several demand profiles in the same line in order to provide support for multi-variant or multi-product systems. Finally, a series of possible alternative configurations of processes are taken into consideration so as to integrate the balancing of the line with process design and equipment specification.
This paper is aimed at reducing the costs, maintaining the quality and designing the plant layout that is flexible to meet the customer demand. A number of stations in the after test assembly and ...after paint assembly are selected for capturing the production process requirements. Then, failure mode and effects analysis of after test assembly is carried out. Layout designs for the after test assembly and after paint assembly are developed using systematic layout planning and are validated using Spaghetti diagrams. With the improved layout, considerable reduction in the distance moved by the operator has resulted in 20% cost saving at 80% Takt time.
Purpose
The paper delivers an approach of how lightweight robot systems can be used to automate manual processes for higher efficiency, increased process capability and enhanced ergonomics. To show ...how these systems can be utilized in practice, a new collaborative testing system for an automated water leak test was designed using an image processing system utilized by the robot.
Design/methodology/approach
The ‘water leak test’ in an automotive final assembly line is often a significant cost factor due to its labour intensive nature. This is particularly the case for premium car manufacturers as each vehicle is watered and manually inspected for leakage. This paper delivers an approach that optimises the efficiency and capability of the test process by using a new automated in-line inspection system whereby thermographic images are taken by a lightweight robot system and then processed to locate the leak. Such optimisation allows the collaboration of robots and manual labour which in turn enhances the capability of the process station.
Findings
This paper examines the development of novel applications for lightweight robotic systems and provides a suitable process whereby the systems are optimised in technical, ergonomic and safety-related aspects.
Research limitations/implications
A new automated testing process in combination with a processing algorithm was developped
Practical implications
To optimize and validate the system it was set up in a true to reality model factory and brought to a prototypical status. Several OEM's showed great interest in implementing the system in their assembly line.
Originality/value
A lightweight robotic system was implemented in a continuous assembly line as a new area of application for these systems.
The automated water leak test gives a practical example of how to enrich the assembly and commissioning lines, which are currently dominated by manual labour, with new technologies. This is necessary to reach a higher efficiency and process capability while maintaining a higher flexibility potetial than fully automated systems.
The design and implementation of assembly-line systems have been critical issues for companies since the first assembly-line was started at the Ford Highland Plant in 1913. From that time onwards, ...most companies have met with various problems at the design and implementation stages of assembly-line systems, two of which are the allocation of different work elements to various workstations and the proper equipment selection for workstations. Therefore, in this article, to overcome both the above-mentioned problems, we propose an integrated approach in which a branch and bound algorithm and the analytic hierarchy process (AHP) method are used together. First, the branch and bound algorithm is used to generate a list of assembly-line design alternatives. Then, the generated alternatives are evaluated using the AHP method to determine an optimum solution (the best alternative) at minimum equipment cost. The AHP method is one of the most commonly used multiple-criteria decision-making methods in the literature, and evaluates both qualitative and quantitative evaluation criteria represented in a hierarchical form. The proposed approach is also illustrated on a sample case study.
This paper presents a mathematical model and an adaptation of the Strength Pareto Evolutionary Algorithm II (SPEA2) for the Mixed-Model Assembly Line balancing and equipment selection problem. The ...SPEA2 was enriched with a task and equipment reassignment procedure and aims at supporting the planners to find better solutions in the earliest phases of a production system planning project.
This study integrates vibrations aspects in the Assembly Line Design Problem (ALDP). During the last decade, ergonomic aspects have been considered by several points of view in the assembly design ...problems in order to reduce work-related musculoskeletal disorders. However, the workers vibration exposure level, caused by the use of automatic tools to perform some tasks, has not still discussed as a part of ALDP. For this reason, a new model is here proposed to compare the total costs of an assembly line with and without the integration of the ISO 5349-1, the European norm that defines the vibration exposure limit for workers. The application of the model here proposed in two real industrial contexts shows the effects of the vibration level maximum exposure in the final assembly line design costs.
In mass production, assembly-line balancing (ALB) problem has been a critical and repetitive issue for companies for long time. On the other hand, equipment selection for stations has also been ...another important problem at the design stage of an assembly-line system. In this paper, both problems are handled simultaneously. Therefore first, goal programming (GP) method, a well-suited technique is used to develop a preemptive formulation to joint both of the problems, when the nature of the problem consists of several conflicting objectives, and some mathematical constraints on solutions. Second, an AHP method based on fuzzy scales which is incorporated with the GP is also used due to the fact that it takes both qualitative and quantitative judgments of decision-maker(s) into consideration to rank the equipment alternatives for stations by weight. The fuzzy AHP as one of the most commonly used multiple-criteria decision making (MCDM) methods has been effectively used for more than decade in both academic research and practice, and takes the vagueness and uncertainty on judgments of decision-maker(s) into consideration due to the fact that the crisp pairwise comparison in the conventional AHP seems to insufficient and imprecise to capture the right judgments of decision-maker(s). In short, in this study, a combined fuzzy AHP-GP approach is proposed to evaluating assembly-line design alternatives with equipment selection. An integer GP formulation is constructed, which also uses the fuzzy AHP scores of equipment alternatives, and employs them as one of the goals. Then, the mathematical model is solved to find out the ultimate alternative in terms of the minimized equipment cost and the maximized preference measures of decision-maker(s). The proposed approach is also illustrated on a sample case study.
Hybrid analytic and simulation models are used in solving complex problems in a variety of domains, but are less commonly used in production system design. This paper reviews hybrid approaches and ...their applications, proposes a new hybrid modeling class, and illustrates a cost function for selecting analytic or simulation modeling approaches via a problem solving process. To illustrate the new class, a case study is presented, in which a hybrid analytic and simulation modeling approach is used in designing a multi-stage, multi-buffer electronic device assembly line. Development of a robust integrated modeling support environment is proposed as a future direction.
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