How to Balance an Assembly Line
Line balancing levels work across stations so each one sits just under takt — cutting idle time and bottlenecks. Here is the sequence, step by step.
Steps to balance a line
- 1
Document the process and precedence
List every task with its time, and the order constraints (what must come before what). A precedence diagram makes valid groupings clear.
- 2
Total the work content
Add up the time of all tasks. This total, against takt, sets how many stations you theoretically need.
- 3
Calculate the minimum stations
Minimum stations = total work content / takt time, rounded up. This is the best case before precedence and practical constraints.
- 4
Assign tasks to stations
Group tasks so each station's load is as close to takt as possible without exceeding it, while respecting precedence.
- 5
Validate and measure
Check layout, ergonomics and equipment, then measure efficiency = total work content / (stations × bottleneck cycle time). Iterate to close the gap.
Frequently asked questions
What is takt time's role in balancing?
Takt is the target every station must fit under. Balancing redistributes work so each station's load is at or just below takt, matching output to demand.
How do I know the line is well balanced?
By line efficiency = total work content / (stations × bottleneck cycle time). Many manual lines start at 60–75%; well-balanced lines reach 85–95%.
What if one station is always the bottleneck?
Move work off it (within precedence rules), split its tasks, or improve the method. The Yamazumi chart shows exactly how much to shift and where.
Related lean tools & guides
Balance against takt, live
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