Value Stream Mapping (VSM)

Building a current state value stream map starts by selecting a product family — a group of products that follow a similar processing path. Walk the process from shipping back to raw material receiving (going backward ensures you see the actual flow rather than the assumed flow). At each process step, record key data: cycle time, changeover time, number of operators, uptime/availability, batch size, and working time. Between process steps, count the inventory (raw material, WIP, and finished goods) and calculate how many days of demand each buffer represents. Map the information flow: how does the customer communicate demand? How does the planner create schedules? How do operators know what to produce next? Draw the timeline at the bottom showing processing time (value-adding) and wait time (non-value-adding) at each step. The ratio of total processing time to total lead time is your process cycle efficiency — a measure of how much of the lead time actually adds value. In most factories, process cycle efficiency is below 5%, meaning 95% of lead time is spent waiting. This insight alone is often a catalyst for improvement.

The future state map represents the improved value stream you want to achieve. It is designed by applying lean principles to the current state: Where can continuous flow replace batch processing? Where should pull systems (supermarkets and kanban) replace push scheduling? What is the takt time, and how should processes be balanced to match it? Where can changeover reduction enable smaller batches? The future state map should be ambitious but achievable within 6–12 months. Common future state design elements include combining adjacent process steps into flow cells, replacing large finished goods warehouses with small supermarkets replenished by kanban, implementing heijunka (level scheduling) at the pacemaker process, and reducing changeover times to enable mixed-model production. The gap between current and future state maps generates a concrete implementation plan — a list of kaizen events and projects, each targeting a specific improvement shown on the map.

Value stream mapping is particularly revealing when applied to the scheduling process itself. Map how customer orders flow from receipt through order entry, demand planning, capacity checking, schedule creation, and shop floor release. You will typically find that orders queue at multiple points — waiting for batch processing in MRP, waiting for planner review, waiting for capacity confirmation — adding days of lead time without adding any value. The information timeline on a VSM often shows that it takes 3–5 days from order receipt to shop floor release, even though the actual planning work takes only minutes. A future state scheduling process might include real-time order entry that feeds directly into a visual scheduling tool like LinePlanner, automatic capacity checking against current production line status, and same-day or next-day production release for standard orders. By reducing the scheduling lead time from days to hours, the entire manufacturing lead time shrinks correspondingly — and customer responsiveness improves dramatically.