Milk Run Route and Replenishment Frequency

Why it matters

A milk run is a regular material replenishment route. The vehicle leaving the source serves defined points of use, collects empty containers and returns to a state ready for departure again. The route line does not only show which aisle is taken; it must also carry what is to be left where and when. The source, point of use, container and frequency information in the plan for every part turns here into a physical sequence. A material without an address is not counted as added to the route. A distance that looks short on the map may not fit the planned interval once the required services and the return preparation are included. For this reason distance and time are measured separately and interpreted together.

Route time and departure interval are not the same concept. Route time is the time until a vehicle returns to the state in which it started. Departure interval is the time between consecutive planned departures. A single vehicle cannot start a new cycle before it finishes the previous one. Two vehicles can depart at different times; but for this the vehicle, the driver and the shared service points must also be suitable. The priority in this lesson is that the route closes in terms of time. The detailed test of the number of vehicles and drivers is made in the next lesson. Writing an extra vehicle does not remove a conflict at a narrow loading point or a missing service time.

A regular route does not mean that every stop consumes the same quantity. One point may ask for frequent replenishment while another can be fed less often with a larger container. When different service frequencies are placed on a fixed path, some cycles can be longer. The average route time should not hide these longer cycles. It must be clear which stops each planned departure will visit. Collecting empty containers and separating unsuitable material also take time. Especially in the first and last cycle, the starting stock, the return load and the end-of-work conditions may differ from the regular period. Instead of passing them with the same assumption, they need to be checked separately.

Route design is not an exercise in driving the vehicle faster. Safe passage, visibility and stop access are the acceptance conditions of the design. If travel time is to be reduced, unnecessary wandering, a wrong source arrangement or the delivery sequence are examined. Removing a safe wait at an intersection is not accepted as a time gain. When replenishment is made more frequent, line-side stock can decrease; in return, more departures and service work arise. With less frequent replenishment, transport becomes easier while the space requirement of the point of use can grow. The workable choice is made among options that keep the same demand and the same safety condition; it does not rest only on the shortest route time. The value of a regular visit is that the worker knows when the material will arrive without having to look for it. This predictability is preserved only by the deliveries that actually happen. If departure times keep changing, a fixed route line alone does not create a regular service. The reliability of the plan should be assessed with the real delivery interval at the point of use and with deviations that can be explained; the movement record at the source alone is not enough.

Formula