Scenario
The factory produces 500 units per day. The production manager said: "We can make 600 units a day, capacity is more than sufficient."
The customer suddenly requested 480 units per day. You check the production line and find that Station A takes 90 seconds per unit, Station B takes 75 seconds, and Station C takes 60 seconds.
If Takt Time is 1 minute (8 hours / 480 units), Station A has already exceeded Takt Time by 50%—it is the real bottleneck.
Calculating Takt Time
Takt Time = Available Production Time / Customer Demand Quantity
Example:
- Daily shift: 8 hours = 480 minutes
- Deduct breaks: 30 minutes
- Available production time: 450 minutes
- Customer demand: 450 units/day
- Takt Time = 450 minutes / 450 units = 1 minute/unit
Takt Time represents: One product must be completed every 1 minute to meet customer demand.
Differences Among Three Times
| Term | Definition | Determined by |
|---|---|---|
| Takt Time | Customer demand rate | Customer order |
| Cycle Time | Actual time to complete one unit at each station | Process design |
| Lead Time | Total time from order to delivery | Entire value stream |
Golden Rule: Cycle Time ≤ Takt Time
Any station with Cycle Time > Takt Time = That station is a bottleneck.
Production Line Balancing Efficiency
Production Line Balancing Efficiency = Sum of all station Cycle Times / (Takt Time × Number of Stations)
Example:
- 5 stations, Cycle Times respectively: 55, 60, 48, 52, 45 seconds
- Sum: 260 seconds
- Takt Time = 60 seconds, 5 stations
- Balancing Efficiency = 260 / (60 × 5) = 260 / 300 = 86.7%
86.7% means there is 13.3% waiting waste at stations. Perfect balance = 100% (practically impossible, 85-90% is a reasonable target).
Planning Manpower with Takt Time
If demand increases, Takt Time shortens:
- Takt Time shortens from 1 minute to 45 seconds
- The bottleneck station, originally 55 seconds, now exceeds Takt Time even more
- Required: split operations, add workstations; or invest in automated equipment
Golden Quote
"Takt Time is not your production rate; it is the rhythm given to you by the customer. Faster than Takt Time means producing excess inventory; slower than Takt Time means failing to deliver orders. The goal of production line design is to ensure all stations closely adhere to Takt Time, neither too fast nor too slow."