Implementing Line Balancing with Simulation

What is line balancing?

Line balancing is the leveling of the workload across all operations in a manufacturing line to remove any bottlenecks and excess capacity. The 'line' could be an assembly line or modular line and will likely have many work stations with varied tasks and work contents.

Manufacturing throughput is dependent on the length of time each task takes on the line, the number of staff available and their skill level, machine capacity and in the case of mixed assembly lines, changeover times.

When designing and managing a mixed-model line assembly, system engineers strive to satisfy a number of objectives including:

• Maximizing line throughput
• Minimizing the number of stations
• Maintaining a balance of work across stations
• Satisfying delivery rates
• Accommodating product mix changes

These goals ensure that production schedules are continually met, manufacturing costs are kept low and ensure that the quality of goods is maintained.

Common line balancing challenges

With so many different and potentially conflicting requirements on the system, as well as interdependencies between process constraints and design objectives, the outcomes of line balancing process design, or re-design, can be difficult to predict. If new processes create bottlenecks at any point in the system, this can negatively impact the whole line and overall throughput.

Designing a new system or re-designing an existing assembly line incorrectly can result in lost production, substantial revenue losses and overworked operators.

Analytical methods can be used, but are limited due to the dynamic nature of the system. The impact of buffering, shift patterns, and product sequence quickly confounds this approach for line design and balancing.

Other factors that add complexity to the design of an assembly line include:

• Reliability of equipment
• Availability of operators
• Size of line buffers
• Sequence and mix of product
• Delivery rates and volume