Line balancing

Line balancing is a production strategy that allows more effective management of production line. In line balancing, managers and engineers strive for configuration of each production line segment that won't create bottleneck. Productivity of each low-productive segment should be improved by reorganization, investments or training. Results of optimization are sometimes documented as good manufacturing practices.

Line balancing allows companies to optimally use resources, including employees, reduce stocks between production line segments, and finally implement just in time concept. Therefore, line balancing doesn't necessarily improve productivity of whole line, but it always reduces costs and improves efficiency.

Assembly line balancing is one of the challenges arising during the development of the technological process. It's very complicated task included in the NP-complete classes. Moreover, this grup consists of many calculation problems. Its actual value of complexity and significant cost reduction connected with their optimization still make them examined in terms of practical algorithms. It contains planning, compression, combination, and sequencing. The development of the alorithm makes production line balancing more universal (J.Żurek, M.Pastwa, M.Wiśniewski 2013, p.61).

The line balancing problem (LBP)

The LBP can be presented in the following way: taking into consideration series of tasks with specific features such as different length and limitation of priority. It means that precondition of some tasks is making one or more tasks and defining the cycle time - how the tasks should be spread out on the assembly line in the certain way so that:

1. no workstation needs more time than a cycle
2. the priority restrictions are respected (E.Falkenauer, A.Delchambre 2002, p.1).

Types of simple assembly line balancing

"Depending on the product, assembly line balancing can be in form of one of the three types of tasks described below:

1. SALBP-1[4] - minimisation of the m number of stations at a given pro-duction rate c:min{m|(m,c)is feasible for a given c production rate},
2. SALBP-2[3] - minimisation of the c line production rate with a given number of stations: {c|(m,c) is feasible for the m number of stations},
3. SALBP-E - maximisation of the E line effectiveness, that is minimisation of the product of $m\cdot c$, max{ $t_{sum}$ / $(m\cdot c)$ | (m,c) is feasible for possible m and c vaues}." (J.Żurek, M.Pastwa, M.Wiśniewski 2013, p.65).

Classification of assembly line balancing(ALB) problems

There are several categories of the assembly line balancing problems. They can be classified on the basis of:

1. the amount of models which were produced on the production line
2. the character of the performed tasks' time (probabilistic or deterministic)
3. the flow character (straight-type or U-type).

We define assembly system of a single model when it comes to only one model produced on a production line. If not, we talk about multi-model assembly system which, as a name says concerns not only a single model. As mantioned above performed tasks' time can be deterministic or probabilistic. Deterministic time may occur in a situation when tasks are being made by using all advanced tools and devices by highly qualified employees (P. Sivasankaran, P. Shahabudeen 2014, p.1667).

Examples of Line balancing

• The most common example of line balancing is the assembly line. In the assembly line, products are constructed in a series of individual tasks that are performed in a specific order. Each task must be completed in the same time frame in order to keep the production line running smoothly. This requires careful planning and management of the production process to ensure that there are no bottlenecks or delays.
• Another example of line balancing is in the manufacturing of automobiles. Automobile manufacturers use line balancing to optimize their production process. They must ensure that each step of the production process is completed in the same time frame, and that each station is staffed with the right number of workers to complete the task.
• Another example of line balancing is in the food industry. The food industry requires careful management of the production process in order to produce consistent and safe products. Line balancing ensures that each step of the production process is completed in the same time frame, and that each station is staffed with the right number of workers to complete the task. This helps to ensure that the food is produced to the highest quality standards.

Advantages of Line balancing

Line balancing has many advantages that help to increase productivity and efficiency of production lines.

• It helps to optimize the process, reducing idle time and improving throughput. It can also help to reduce cost of production and minimize the need for additional workers.
• Line balancing helps to ensure that the production line is operating at its peak efficiency, reducing the amount of wasted time and materials. It also helps to identify potential problems before they arise and to prevent them from occurring.
• Line balancing can also help to improve product quality, as it focuses on ensuring that all process steps are performed in an efficient and consistent manner. This helps to reduce errors and defects and improve customer satisfaction.
• Line balancing also helps to improve worker safety, as it reduces the risk of accidents and minimizes the amount of physical strain on workers. This can result in a healthier and more productive workforce.

Limitations of Line balancing

Line balancing is an effective production strategy, however it has some limitations. These include:

• Time-consuming process - Line balancing can be a lengthy process, as it requires gathering of information about production process, analyzing data, and modelling line balancing solutions.
• Risk of human error - During line balancing process human errors can occur, which can lead to wrong results in the end.
• Limited benefits - In some cases line balancing may not have much of an effect on production process, which can lead to dissatisfaction with line balancing results.
• Risk of overproduction - If line balancing is not done carefully, it can lead to production of more products than needed, which can lead to overstocking and increased costs.
• Limited resources - In some cases, companies may not have enough resources to implement line balancing, as it requires additional investments.

Other approaches related to Line balancing

Other approaches related to line balancing often involve reorganization, investments, or training.

• Process Mapping: This involves creating a diagram or chart of the process that is being undertaken, which can help identify potential bottlenecks.
• Scheduling: Scheduling helps to plan out the production process in advance, allowing for better management of resources and people, and reducing the risk of bottlenecks.
• Workload Balancing: This involves redistributing the workload across the line in order to ensure that all segments are working at the same level of efficiency.
• Automation: Automation can help reduce the manual labour required, which can increase productivity and reduce the risk of bottlenecks.
• Standard Operational Procedures: Establishing standard operating procedures can help ensure that the production process is followed consistently, which can help to prevent bottlenecks.

In summary, there are a number of different approaches to line balancing, such as process mapping, scheduling, workload balancing, automation, and standard operational procedures. These can help managers and engineers ensure that each production line segment is configured to prevent bottlenecks and improve productivity.

Line balancing — recommended articles

Single minute exchange of die — Jidoka — Quality control — 7 wastes of lean — Job simplification — Cycle time — Quality inspection — Quality assurance — Zero defects

References

• Battaïa O., & Dolgui A. (2013). A taxonomy of line balancing problems and their solutionapproaches. International Journal of Production Economics, 142(2), 259-277.
• Falkenauer E., Delchambre A. (2002). A Genetic Algorithm for Bin Packing and Line Balancing, "IEEE", p.1
• Otto A., Otto Ch., Scholl A. (2014). How to design effective priority rules: Example of simple assembly line balancing, "ScienceDirect", Vol.69
• Sivasankaran P., Shahabudeen P. (2014). Literature review of assembly line balancing problems, "Springer London", Vol.73
• Żurek J., Pastwa M., Wiśniewski M. (2013). Simple assembly line balancing, "ATMiA", Vol.33, No.4, p.61, 65

Author: Karolina Korbut