Bottleneck
The slowest process or machine in a production line that limits overall output.
Bottleneck is the operation, machine, or process in a production line that has the lowest capacity, thereby limiting the overall output of the entire system. Like the narrow neck of a bottle restricts liquid flow regardless of how wide the bottle body is, a bottleneck operation restricts production flow no matter how efficient other processes are. Identifying and managing bottlenecks is critical for improving throughput and reducing lead times.
Understanding Bottlenecks
In any production system with multiple sequential operations, one operation will always be the slowest—that's your bottleneck. The reality of bottlenecks:
- There's always one: Eliminate current bottleneck, another process becomes the new bottleneck
- Controls entire system output: System can produce only as fast as the bottleneck allows
- 100% utilization desired: Bottleneck idle time directly reduces factory output
- Non-bottlenecks should have idle time: Running non-bottlenecks at 100% just creates excess WIP
Real Manufacturing Example
Company: Metal furniture manufacturer making office desks
Production Process & Capacity:
| Operation | Time per Unit | Daily Capacity (8 hrs) |
|---|---|---|
| 1. Cutting | 15 minutes | 32 units |
| 2. Welding | 40 minutes | 12 units ⚠️ BOTTLENECK |
| 3. Grinding | 20 minutes | 24 units |
| 4. Painting | 25 minutes | 19 units |
| 5. Assembly | 18 minutes | 26 units |
Analysis: Welding with 12 units/day capacity is the bottleneck. Entire factory output limited to 12 desks per day, regardless of other operations being capable of higher output.
Observable Symptoms:
- Cut parts pile up before welding station (waiting queue)
- Welding station always busy, never idle
- Grinding, painting, assembly workers have idle time (waiting for welded frames)
- Overall factory utilization seems low despite welding running at 100%
How to Identify Bottlenecks
Method 1: Observation (Walk the Floor)
- Look for WIP piles—large inventory accumulation before a workstation indicates bottleneck
- Find always-busy operations—bottleneck never has idle time
- Identify idle downstream operations—waiting for upstream bottleneck to feed them
Method 2: Time Study
- Measure cycle time for each operation
- Operation with longest cycle time is likely bottleneck
- Calculate theoretical capacity: Working Hours / Cycle Time per Unit
Method 3: Data Analysis
- Track actual output per operation over time
- Operation consistently producing least output is bottleneck
- Monitor machine utilization—bottleneck should have ~95%+ utilization
Strategies to Eliminate Bottlenecks
1. Add Capacity at Bottleneck
- Buy additional machine: Add second welding station (doubles welding capacity to 24 units/day)
- Add shift: Run welding operation overtime or second shift while other operations run single shift
- Offload work: Subcontract welding to external job workers during peak demand
2. Increase Bottleneck Efficiency
- Eliminate downtime: Preventive maintenance to avoid breakdowns at bottleneck operation
- Reduce setup time: Quick changeover techniques (SMED) so bottleneck spends more time producing
- Improve methods: Better jigs, fixtures, tooling to reduce cycle time
- Skill upgrade: Put most experienced operators on bottleneck machines
Example: Analyzed welding operation, found 30 minutes/day lost in setup and electrode changes. Batch similar products together, pre-stage electrodes, reduced non-productive time to 10 minutes. Effective capacity increased from 12 to 13 units/day (8% improvement).
3. Shift Load Away from Bottleneck
- Redesign product: Change design to reduce welding complexity or use bolt connections instead of welding where possible
- Pre-processing: Do some activities before bottleneck (e.g., pre-tack weld at cutting stage) to reduce time at bottleneck
- Downstream processing: Move non-critical activities to after bottleneck
4. Ensure Bottleneck Never Starves
- Buffer before bottleneck: Maintain small queue of work waiting at bottleneck so it never runs out of material
- Priority feeding: Cutting department prioritizes supplying welding over building excess inventory
- Protect from defects: Inspect parts before welding to avoid wasting bottleneck capacity on defective parts that will be rejected later
Theory of Constraints (TOC) Five Focusing Steps
Dr. Eliyahu Goldratt's systematic approach to bottleneck management:
- IDENTIFY the bottleneck: Which operation limits overall output?
- EXPLOIT the bottleneck: Make sure it runs at maximum efficiency (no downtime, best operators, preventive maintenance)
- SUBORDINATE everything else: Other operations should support bottleneck (don't overproduce and create excess WIP)
- ELEVATE the bottleneck: If still insufficient, add capacity (buy equipment, extra shift, outsourcing)
- REPEAT: Once bottleneck is broken, new bottleneck emerges—go back to step 1
Common Mistakes in Bottleneck Management
- Maximizing efficiency everywhere: Running all machines at 100% creates WIP mountains. Only bottleneck should run at full capacity
- Batch sizes ignoring bottleneck: Large batches at non-bottlenecks create long wait times at bottleneck
- Improving wrong operations: Investing in faster cutting machine when welding is bottleneck doesn't increase output
- Not protecting bottleneck: Allowing bottleneck to sit idle due to material shortages or quality issues
Shifting Bottlenecks
Bottlenecks can shift based on product mix. Product A bottleneck may be welding, Product B bottleneck may be painting. Production scheduler must be aware of which operations are bottlenecks for which products and schedule accordingly.
How Manufacturing ERP Tracks Bottlenecks
Systems like Karygar track operation-wise cycle times and WIP levels. Real-time dashboards show which operations have highest WIP queues and longest wait times, identifying bottlenecks instantly. Historical data analysis shows capacity utilization trends, helping prioritize capacity expansion investments. Production scheduling algorithms ensure bottleneck operations are always fed work without starving or overloading.
See Bottleneck in Action
Don't just read about Bottleneck. See how Karygar automates this process to reduce manual work and errors on your factory floor.