Lean Foundations — Lesson 3: Value Stream Mapping (VSM): Seeing the Entire Process on One Sheet of Paper

Lean Foundations · 4 min read · 04.09.2026

The third lesson of the Lean Fundamentals series. In the first, you learned to recognize the seven types of waste right at the workstation; in the second, you used 5S to build order that lasts even after the third month. Today we look wider — at the entire process. You will learn Value Stream Mapping (VSM): draw the path of a single product family from supplier to customer on one sheet of paper, count how much time in it actually adds value, and see where waiting piles up. All you need is a pencil, paper, and a few hours on the shop floor.

A value stream map is not a flowchart

A flowchart captures the steps of a process. A value stream map also captures the flow of information: where the order comes from, who issues work orders, and what production is based on — make-to-order or make-to-stock. The biggest waiting is usually caused not by the machines, but by the way we manage them.

Don't draw the entire product range on the map. Select one product family — a group of products that go through similar operations. The 80/20 rule helps: one fifth of the range accounts for four fifths of the volume. Choose the most challenging family and leave the rest aside.

And the first rule: map the current state, not the wish. On our projects, teams often draw the state they wish they had — such a map shows nothing. Draw the process as it is. Including the intermediate warehouses.

How to draw the current state — a one-day procedure

Don't do it alone. It goes faster as a pair — one person draws the map, the other records data and asks people on the shop floor.

1. Mark the boundaries of the map: supplier on the left, customer on the right, workstations in between.
2. Walk the process physically on the shop floor, in the direction of flow. The ERP system shows what should be; stock cards and shelves show what actually is.
3. In the data box of each workstation, record the cycle time (C/T), changeover time (C/O), number of shifts, availability, and batch size.
4. Count the inventory between operations and convert it to days: quantity divided by daily demand.
5. Draw a timeline at the bottom: processing times per operation on top, waiting times below.
6. Add up the total lead time and the value-adding times.

Draw in pencil — you will redraw the first map anyway.

How does it turn out in practice? At an engineering company with 120 employees, we measured 6 operations totaling 45 minutes of processing per piece. The lead time from material intake to shipment? 21 working days. Value-adding time made up 0.2 percent. The remaining 99.8 percent was waiting — in queues, intermediate warehouses, and moves.

What to read from the map first

The biggest number on the map is usually not the cycle time, but the inventory between operations. The calculation is simple: 2,400 pieces in front of assembly with a daily demand of 400 means 6 days of waiting in one place. Every day of waiting ties up capital. And it hides problems that would surface immediately in a continuous flow.

Everyone can see waste at a single workstation. Only the map can see waste between workstations.

A large inventory between two operations usually means that one produces faster than the other can keep up with. The fault lies neither with the foreman nor the operator, but with the way we manage the flow.

On the first map, look for three things: where the part waits the longest, which changeover forces production in large batches, and where the flow breaks from one piece to a batch. Here we build on the first lesson: you have looked for the seven types of waste in isolation; the map shows where they accumulate and in what volume.

This week's exercise

Don't turn mapping into a month-long project. The goal of the first round: draw, calculate, find the three biggest waits. You will design the future state later — first you must see the reality.

Task: select one product family and walk its flow from material receipt to shipment. At each workstation, note the cycle time, changeover time, and pieces between operations. Then calculate the lead time, value-adding time, and their ratio. Find the three biggest waits. Time required: 60 to 90 minutes on the shop floor plus half an hour of calculations. Show the result to the foremen — you will see which number surprises them.

If the Lean Fundamentals series works for you and you want to go through the complete lean fundamentals with a trainer and exercises on your own data, see our e-learning offer. We also map value streams right on the shop floor as part of our consulting — the details are in the overview of our services. And when the map shows that long changeovers keep the batches large, we have a tool: in the fourth lesson, we cover SMED — how to shorten changeovers and produce smaller batches without losing capacity.

Quiz — test your knowledge