Balancing, sequencing and determining the number and length of workstations in a mixed model assembly line fatemeh mohebalizadehgashti advisor. Line balancing is the problem of assigning operation to workstation along an assembly line, in such a way that assignment is optimal in some sense. Optimization of balancing for a mixed multi model assembly. Optimization of balancing for a mixed multi model assembly line. A focus on model formulation 6412 line balancing problem mmabp by considering the three objective functions based on demand ratio. In this paper, we propose mixed integer programming mip. Mathematical modelling of mixedmodel assembly line.
Using this method, the virtual model simulation and control logic of transmission is done and the results were found feasible. It provides shorter line length, reduced throughput time, lower cost of tools and fixtures, and less material handling kim et al. Balancing mixedmodel assembly lines in real world complex. Sivasankaran and shahabudeen 6 developed a hybrid mathematical model for the single model assembly line balancing problem. So this internal mixed model determines the assembled on the same line. Abstract the fundamental of assembly line balancing problems is to assign the tasks to an ordered sequence of sta. Adaptation of some assembly line balancing heuristics to a. Mixed model line balancing and scheduling assembly line. The general tendency in current studies is to deal with these problems in different time frames. Analysis of the type ii robotic mixedmodel assembly line.
A mixedmodel assembly line can manufacture different products in the same assembly line, providing flexible production according to demand seasonal behavior. Mixedmodel ushaped assembly line balancing problems. Mixedmodel alb is categorized under general assembly line balancing which produce several models having similar characteristics on a single assembly line 4. Research on uncertainties influenced the mixedmodel. On the other hand, market conditions have increased the importance of mixedmodel assembly lines. Hence, in this paper, an attempt has been made to analyze the extent of differences. For a smlbp, however, only one precedence diagram is given. Given p models, the set of tasks and a cycle time associated with each model, the performance times of the tasks, and the set of precedence relations which specify the permissible orderings of the tasks for each. The line balancing module leverages assembly planners process planning structure that makes it easy to identify common tasks as well as tasks that are unique to one or more product model or option. This is ba sed upon neglecting the model to model variation of cy cle time. Assembly lines are production flow lines which meet the standard of commonalities in case of mass production and in low volume production as well. Repeat for following workstations until all tasks are assigned. However, in todays competitive market, the mixed model assembly line balancing problem has been turned into an operational problem.
Mixed model assembly line the use of mixed model assembly lines in a changing environment requires methods for efficient design and redesign of the assembly system in which they are used. A common assumption in the literature on mixed model assembly line balancing problem is that the task duration is known and deterministic but may differ among various models. The amount of work required to assemble units can vary from model to model, creating an uneven flow of work along the line. Balancing and sequencing of mixed model assembly lines.
Heuristics for mixed model assembly line balancing problem. Assign tasks to first workstation, using rules and staying within cycle time. Pastor and andres 9 considered a company producing four different product models. This paper presents a new approach for the mixed model assembly line balancing problem, which includes some issues that reflect the operating conditions of real world assembly lines such as parallel workstations and zoning constraints. Previous approaches for balancing mixedmodel assembly lines rely on detailed prognoses of the demand for each model to be produced on the line modelmix.
For a large number of uncertainties such as suppliers, customer demand and different external uncertainties, as well as workers, machines, environment and other internal uncertainties, they affects the mixedmodel assembly line balancing. Mixed model assembly line literature involves two problems. It needs high capital investment in installation and redesigning the paced lines. On a mixed model line every model has its own precedence diagram, and a bal ance may not violate any of these orderings. Mixedmodel, twosided, assembly line, genetic algorithm. Mixedmodel multimanned assembly line balancing problem. A new comsoal based heuristic approach to mixed model. In this direction, assembly line balancing helps an organization to design its assembly line such that its balancing efficiency is maximized. Mixed model assembly line balancing problem under uncertainty. Multiobjective optimization algorithms for mixed model. The paper uses the complexity definition and the related analysis model, proposed in zeltzer et al. This paper is the first one of the two papers entitled modeling and solving mixedmodel assembly line balancing problem with setups, which has the aim of developing the mathematical programming formulation of the problem and solving it with a hybrid metaheuristic approach. This problem has attracted a number of research fields. Every chart view and report wtihin line balancing then provides an aggregated and detailed analysis of the varying labor time that each product.
Multiobjective optimization algorithms for mixed model assembly line balancing problem with parallel workstations masoud rabbani1, reyhaneh siadatian1, hamed farrokhiasl2 and neda manavizadeh3 abstract. It was originally developed to support mass production of single homogeneous standardised com. And the type of assembly line in which workers work in different models of a product in the same assembly line is called mixed assembly. Adaptation of some assembly line balancing heuristics to a mixedmodel case this master thesis propose to find the best heuristic solution for one of the types of assembly line balancing problem, the salp1, in a line that needs to produce different models of. However, in order to effectively manage such lines under realworld conditions, there is a. The results were considered satisfactory when assessed in terms of production capacity, manufacturing cycle time, and assembly line balancing. With mixed model assembly, figure 4, multiple models are interspersed on the same assembly line. This assembly system design is focused on issues of assembly system or line configuration, balancing, and equipment selection. This project mainly focuses on improving overall efficiency of single model assembly line by reducing the bottleneck activities, cycle time and distribution of work load at each work station by line. Mixed model assembly line in this model the setup time between the models would be decreased sufficiently and enough to be ignored. A new comsoal arcus, 1965 based heuristic procedure has been. Therefore, in this article, the robotic mixedmodel assembly line balancing problem is studied. An example of line balancing assigning tasks to stations a precedence diagram is a lot like a process flow diagram.
Under these circumstances, the mixed model assembly line balancing problem arises to smooth the production and decrease the cost. This paper summarizes the assembly line balancing terminology, the computational methods, and objective functions applicable to a wide variety of assembly lines. Mixed assembly line balancing method in scenarios with. Mixed modelassembly line balancing problem underuncertainty. Mixedmodel assembly lines are a type of production line where a variety of product models similar in product characteristics are assembled.
The strategic shift took effect due to the diversified customer needs along with the individualization of products. This eventually triggered the research on al balancing. Balancing and scheduling of flexible mixed model assembly. Defersha the single model assembly line is a traditional type of assembly line, which assembles only one product in a large quantity. One important step in taking advantage of robots on the assembly line is considering them while balancing the line. On a multi model line the different models are produced in batches. This article proposes a heuristic that aims to balance production lines subjected to several product models in order to attenuate capacity restrictions in workstations and increase the. Single and mixedmodel assembly line balancing methods for. If the organization assembles more than one model in the same line, then the objective is to maximize the average balancing efficiency of the models of the mixed model assembly line balancing problem. This special kind of assembly line is usually utilized to assemble different models of large products, such as buses and trucks, on the same production line. Line balancing techniques to improve productivity using. Multi model assembly line in this model the uniformity of the assembled products and the production system is not that much sufficient to accept the enabling of the product and the production levels. Subsequently, it proposes a mixedmodel assembly line balancing optimization model to determine a line balance that.
Sequencing problems are important for an efficient use of mixed. Single and mixedmodel situations for both constant and variable work element times are examined. The ratio of each model to total output is consistent with customer demand. Production is initiated with a job which is a workpiece that is launched down the line. They developed a mathematical model for this problem. Balancing, sequencing and determining the number and.
Cardinality constrained parallel machine scheduling. Recent trend in mixedmodel assembly line balancing. The mixed model line balancing problem mimlbp the smlbp and the mimlbp differ in the prece dence constraints. An assembly line comprises a sequence of workstations through which a predefined set of tasks are performed repeatedly on product units while they are moving along the line. To stay efficient, management decisions for the line such as number of workers and assembly task assignment to stations need to be optimized to increase throughput and decrease cost. A mixedmodel assembly line balancing problem can be stated as follows. Mmalb is a nondeterministic polynomialtime hard problem which requires an effective algorithm for solution.
This results in the simultaneous assembly of two or more different. Modeling and solving mixedmodel assembly line balancing. On mixed model lines, how ever, the lot sizes equal one. Assembly lines are cost efficient production systems that mass produce identical products. Due to customer demand, manufacturers use mixed model assembly lines to produce customized products that are not identical. This paper deals with mixed model assembly line mmal balancing problem of typei. The objectives are 1 cycle time minimization, 2 workload variation minimization and 3 total cost minimization. Assembly line balancing, mixedmodel uline, jit, coin. Compared with the single model line little attention has been paid to the mixed and the multi model line balancing problem. Usually in a mixedmodel assembly line, the models being assembled have differences in the set of tasks associated with each model, the. Mixed model assembly introduction mixed model production is the practice of assembling several distinct models of a product on the same assembly line without changeovers and then sequencing those models in a way that smoothes the demand for upstream components.
Mixedmodel twosided assembly line balancing using a. Mixedmodel assembly occurs when more than one model of the same general product are intermixed on one assembly line. Sequencing mixedmodel assembly lines in justintime. Introduction the twosided assembly line is a line where tasks on the same product item can be performed in parallel at both sides of the line. The proposed approach was applied to a mixed assembly line composed of seven product models. Thus, in figure 4, there are two yellows for every green and two yellows for every red. Pdf balancing mixedmodel assembly line to reduce work. Determine required workstations theoretical minimum 4. Station parallelism in flexible mixed model assembly lines improves system reliability and enables rapid adaptability to customer demand fluctuations. Such an assembly line is increasingly accepted in industry to cope with the recently observed trend of diversification of customer demands. And these uncertainties can be turned into the changes of demand, operation time and workstation availability, which are relevant to mixedmodel assembly. Due to the combinatorial nature of the line balancing problem, exact solution techniques are limited to small problems. A line balancing approach is needed that can address the complex nature of the mixed model line and produce nearoptimal solutions to problems of realistic size.
To reduce the time and money this assembly is arranged in batches, and this allows the. Pdf mixed model assembly line balancing problem under. In this paper, we study flexible mixed model assembly lines with serially connected stages where stages may have one or more parallel stations. Comparison of single model and multimodel assembly line.