Pick one common item, like a carton of tea, and picture it sitting on a store shelf. That’s just the last step of its supply chain. Before it gets there, it could have gone through a raw-materials supplier, a factory, a distribution center, a trucking company, and a retail store. A process map connects all those steps so you can see how products and data move.
Start by putting the supplier at the far left of the map and the customer at the far right. Then place each link in between in the sequence the item travels. In the case of a simple carton of tea, the supply chain might consist of an ingredients supplier, a packaging supplier, a tea producer, a warehouse, a trucker, and a retailer. Keep the initial process map focused on the primary supply chain participants. You can add more details later once the basic flow of material is complete.
Then, map out the physical movement of the product. Tea leaves and packaging components move to the manufacturer. Completed cartons move to the warehouse, then to the retail store, and finally to the customer. Use arrows to represent this movement. Indicate key processes like receiving, put-away, storage, picking, packing, shipping, and delivery. Doing so helps highlight that a warehouse isn’t just a place where items are stored; it is also a series of activities that affects the speed at which orders are processed and fulfilled.
An effective process map includes both product and information flows. Customer demand might generate a sales order from the retailer, a replenishment request from the warehouse, and a purchase order from the supplier. Shipment notifications, inventory records, delivery confirmations, and demand forecasts may move in different directions than the actual goods. Represent the information flow on a separate line. This can help clarify why an order might be late despite available transportation capacity. The warehouse may have received the goods but not the associated sales order, or a supplier may have begun production after the purchase order arrived late.
After completing the process map, trace it using a single order. Assume the retail store requires 40 cartons of tea. Trace the order request backward through the supply chain and the goods forward to the customer. At each step, determine what needs to occur before the goods are passed along. Is there sufficient stock? Does the minimum order quantity alter the purchase? How long does the supplier take to process the purchase order? Is the carrier able to deliver the goods within the required timeframe? By doing this, you’ll discover that lead time is actually a series of linked periods, not just the time spent in transit.
Newcomers often attribute the delay to the transportation company because delivery is the most apparent part of the process. The process map encourages you to consider other factors. A delayed shipment might originate with a flawed demand forecast, a slow order approval, inadequate safety stock, limited warehouse space, or a lack of information. Mark where the issue originated and then mark where the impact was noticed. Doing so will help distinguish where the root cause lies from where the symptom became evident.
Check your final process map to ensure every arrow represents either a product or information, and that every supply chain partner plays a distinct role. Eliminate any steps that don’t impact your specific example, and add any missing links that might prevent the order from moving forward. A useful process map doesn’t require you to account for every possible supply chain breakdown. Rather, it allows you to illustrate how a product, an order, and an inventory update flow from supplier to customer without losing sight of where the decision-making happens.