Key takeaways
Short answer: A process flow describes the sequence of steps from input to output. A value stream map adds the time at each step, the inventory between steps, the value-add ratio, and the information flow that triggers each step. Process flows are documentation; VSMs are diagnostic tools for improvement. Most "process maps" you see in industry are process flows; calling them VSMs without the timing and inventory data over-promises what they deliver. See also Process Validation vs Process Verification.
A process flow is a sequence diagram: Step A → Step B → Step C → ... → Output. It documents what happens, in what order, at each station.
Useful for:
Not enough for improvement because it does not show where time is consumed or where inventory queues up.
A VSM is a process flow plus four additional dimensions:
The output is usually a timeline at the bottom of the map showing processing time vs total lead time. The ratio is the value-add ratio — and it is usually shockingly low.
A VSM typically reveals that processing time (time the work is being actively done) is a small fraction of total lead time. Common ratios:
This gap is invisible to process flows. VSMs make it visible. And it is usually where the biggest improvement opportunity lives.
Use it to identify improvement targets:
The VSM does not solve anything; it focuses where to look.
1. Drawing a VSM without measuring. Numbers from guess or memory. The map looks complete but misdirects improvement.
2. Map a hundred products on one VSM. Multi-product VSMs become unreadable. One family per map.
3. Map then file. A VSM in a binder produces no improvement. The map must drive specific action.
4. Calling a process flow a VSM. Without timing, inventory, and information flow, it is not a VSM.
A VSM workshop produces two maps:
The gap between them is the improvement plan. Without a future-state map, the current-state map is documentation, not direction.
An OEE platform provides the per-step OEE and changeover time data that VSMs need. Without it, those numbers come from operator memory or one-time observation, which is unreliable.
Fabrico's OEE module exposes per-line OEE, changeover duration, and inventory between connected steps — providing the validated data inputs that a VSM needs to be diagnostic instead of decorative.
See how Fabrico captures this automatically — explore OEE for manufacturing or book a demo.
Swim lanes show who does what; VSMs show time and inventory. They serve different purposes.
A focused VSM workshop is typically 2-3 days for one product family.
Operations, maintenance, quality, planning, plus operators from each station. The map only works if the people who do the work are involved.
After significant process change, or annually. A stale VSM is misleading.
Partly. The data (times, inventory) can be auto-populated from OEE and ERP. The map itself usually needs human curation.
Iniciar sesión
Blog