What makes a process lean
A process is lean when every step either adds value for the customer or is a necessary step that cannot yet be removed, and the work moves through without stopping. Four traits show up again and again:
- Value is defined by the customer. Each step is tested against what the customer would pay for.
- Waste is visible. The eight wastes of lean are named and measured, not tolerated.
- Work flows. Small batches, balanced workloads and short queues replace large batches and long waits.
- The process is standardised and improved. Everyone follows the same standard work, and any improvement becomes the new baseline.
How to build a lean process
- Define value. Write down what the customer wants from this process and what counts as good.
- Map the current state. Use value stream mapping to record every step, wait and handoff, with times.
- Mark the waste. Separate value-adding steps from necessary and unnecessary non-value-adding ones.
- Redesign the flow. Remove or combine steps, cut batch sizes and fix the bottleneck first.
- Standardise. Document the new method so it is done the same way each time.
- Check and improve. Review results on a board each day and run PDCA cycles on the gaps.
Example
A packaging line changes over between products. The team maps the changeover and finds 40 minutes of walking to fetch tools, waiting for a sign-off, and searching for the right settings sheet. They put tools at the line, move sign-off to a checklist and post the settings sheet at the machine. The changeover shortens, and the new method becomes the standard until the next improvement.
Lean process versus lean process improvement
A lean process is the result: a way of working that has little waste. Process improvement is the activity of getting there and keeping it that way. Without a daily routine to review the measures, even a well designed lean process drifts back to old habits.