Assembly Line Balancing Techniques Research Articles

A New Self-Balancing Assembly Line Based on Collaborative Ant Behavior

In most mass-production assembly lines, workers perform a set of tasks repetitively predefined by assembly line balancing techniques. The static task assignment often leads to low productivity when the assembly system faces disruptions or uncertainties such as machine breakdown and uneven worker capabilities. The idea of bucket brigades (BB) has been introduced to address the static assignment problems where cooperative behavior of ants is applied to flow line control. This paper examines possible efficiency losses associated with the existing BB-based assembly cell and presents an improved version for assembly cells under uncertain environments. The new system attempts to enhance productivity by assigning assembly tasks to workers dynamically and possibly adding buffers for decoupling consecutive workers. The proposed assembly system is evaluated through simulation experiments under various manufacturing environments. The experimental results show that the new system provides higher productivity than the naïve BB-based assembly cell as well as traditional assembly cells, especially for uncertain assembly environments.

Öğrencilere Montaj Hattı Dengeleme Tekniklerini Öğretmek için Bir Problem Çözme Ortamı

Assembly line balancing is a production planning strategy that has been widely used in industrial applications. Most line balancing problems are known as nondeterministic polynomial time (NP-hard) problem, and they have different structures and solution methodology approaches. In this study, newly developed production planning software which is called Visual Assembly Line Balancing Software (VALBS) is introduced for educational purposes. The aim of the software is to support teaching activity for assembly line balancing techniques; facilitate understanding characteristics of different assembly lines and solution approaches, and enable to compare the results of them. The proposed VALBS is easy to use in various manufacturing environments, and suitable to support teaching line balancing procedures in undergraduate students. The software was used in classes of industrial and mechanical engineering students and feedbacks of students measured by Likert Scale survey. The results show that proposed visual software is an effective method to teach line balancing procedures.

Analysis of the effect of learning on the throughput-time in simple assembly lines

Calculating the throughput-time of a production run, when a learning effect influences task times, is a complicated but important problem of production management. Classical assembly line balancing techniques assume a constant cycle time. However, if a learning effect is present, cycle time changes for two main reasons. First, cycle time continuously decreases as the operation time of the bottleneck station decreases due to learning. Second, the bottleneck may shift from one station to another, causing further changes in the cycle time. This paper explores the effects of an exponential learning function on the operation of simple assembly lines. An algorithm is presented to determine throughput-time, and a sample problem is provided to illustrate the required calculations. The sensitivity of the throughput-time with respect to the learning rate is also examined, and some general conclusions related to the effect of learning rate changes are presented.

Optimisation of stochastic assembly line for balancing under high variability

An ideal manufacturing system is characterised by deterministic task times, 100% machine availability and on-time delivery. In a real time production scenario an ideal system does not exist due to the presence of variability. Most line balancing approaches assume deterministic task times while ignoring the impact of task time variability on system performance measures. However, in manufacturing systems such as aircraft assembly, ship building and custom job shops which are characterised by high variability in task times, large number of tasks assigned to a workstation and strict task precedence relationship, traditional assembly line balancing techniques may not be effective. In addition to balancing the task times, it is also important to balance the risk of delay. In this research, a novel heuristic optimisation approach for highly variable task times is presented. Results indicate that the method increases throughput while balancing the risk of delays at each station.

Calculation of the Throughput-Time in Simple Assembly Lines with Learning Effect

Calculating the throughput-time of a production run in simple assembly lines is important for several reasons. For example, the length of time to complete a production order is required for planning and scheduling production or the evaluation of throughput-time is required by any effort to improve assembly operations. Classical assembly line balancing techniques assume a constant cycle time. In this case, the calculation of the throughput-time is straightforward. In case of the presence of learning effect, however, cycle time changes for two main reasons. First, cycle time continuously decreases because of the decrease of operation time of the bottleneck station as a consequence of learning. Second, bottleneck may shift from one station to another, causing further changes of the cycle time. In this paper, an algorithm is presented to determine the throughput-time of a production run at the presence of learning based on the residence time of the workstations in the bottleneck. The algorithm and its application are illustrated with a simple example.

Assembly Line Re-Balancing Using Ranked Positional Weight Technique and Longest Operating Time Technique: A Comparative Analysis

Assembly line balancing is an attractive means of mass manufacturing and large-scale serial production systems. Traditionally, assembly lines are arranged in straight single-model lines and the problem is known as Simple Assembly Line balancing problem (SALBP). In this study, two heuristic assembly line balancing techniques known as the Ranked Positional Weight Technique, and the longest operational time technique, were applied to solve the problem of single-model line balancing problem in an assembling company with the aim of comparing the efficiencies of the application of the two algorithms. By using both methods, different restrictions were taken into consideration and two different lines balancing results were obtained. From the results obtained, Longest Operating Time Technique has higher line efficiency (85.16%) as compared to Ranked positional weight technique (79.28%) and it is easy to apply. The LOT technique gave the minimum number of workstations (27) as compared to the RPW technique (29); however the line efficiency and the number of workstation of the existing line are 74.67% and 31 respectively. This implies that the LOT technique has a better reduction in operating cost.

Incorporating ergonomic risks into assembly line balancing

In manufacturing, control of ergonomic risks at manual workplaces is a necessity commanded by legislation, care for health of workers and economic considerations. Methods for estimating ergonomic risks of workplaces are integrated into production routines at most firms that use the assembly-type of production. Assembly line re-balancing, i.e., re-assignment of tasks to workers, is an effective and, in case that no additional workstations are required, inexpensive method to reduce ergonomic risks. In our article, we show that even though most ergonomic risk estimation methods involve nonlinear functions, they can be integrated into assembly line balancing techniques at low additional computational cost. Our computational experiments indicate that re-balancing often leads to a substantial mitigation of ergonomic risks.

Application of assembly line balancing techniques to installment lending operations of commercial banks

Assembly line balancing techniques, originally developed for the manufacturing environment, can be applied to installment lending operations of commercial banks. A case study is presented. The Assembly Line Balancing Module of the STORM Decision Support Software is used in the case study.

A Critique of Some Current Assembly Line Balancing Techniques

This paper briefly reviews the assembly line balancing techniques developed over the last 30 years. It attempts to establish the direction of research, to identify unexplored areas with potential for study and recommends future courses of action.

Incompletion costs versus labour efficiency on the fixed-item moving belt flowline

This paper describes the operation of assembly lines where items are rigidly attached to a moving conveyor bolt and where the processing stations are confined within fixed boundaries. Another mechanical method of product transfer, namely indexing, is also discussed, Both Monte Carlo simulation models and two industrial examples yield convincing evidence that for good flowline design the ratio of on-line inventory to stations should be greater than unity. Such a condition would effectively discriminate against the use of stochastic assembly line balancing techniques, although they have been developed specifically for such systems. In addition, the results confirm that the most economic way of operating these lines is to sot a pace that is fast enough to generate a small proportion of unfinished items.