Pick path optimization is the process of finding an efficient route for workers or robots to collect items from warehouse storage locations. It matters because travel time often takes up the largest share of order picking labor. A better route can reduce walking distance, speed up order fulfillment, lower fatigue, and improve on-time shipping.
In large warehouses, even small savings per order can add up to major cost reductions each day.
The problem is similar to finding a shortest path through a network of aisles, cross-aisles, storage zones, and packing stations. A route must obey warehouse constraints such as one-way aisles, blocked paths, equipment limits, item priorities, and order batching rules. Common methods include S-shape routing, return routing, largest-gap routing, and algorithmic approaches based on graphs.
Modern systems use warehouse management software, barcode scans, RFID, robots, and real-time data to update routes as orders and inventory change.
Key Facts
- Total pick time = travel time + search time + pick time + paperwork or scan time.
- Travel time = travel distance / average walking speed.
- Distance saved = old route distance - optimized route distance.
- Percent improvement = (distance saved / old route distance) × 100%.
- A warehouse route can be modeled as a graph where nodes are locations and edges are walkable paths.
- Batch picking reduces repeated travel by grouping multiple orders into one route.
Vocabulary
- Pick path
- A pick path is the route a worker or robot follows to collect items for one or more orders.
- Warehouse management system
- A warehouse management system is software that tracks inventory, orders, locations, and picking instructions.
- Order batching
- Order batching is the practice of grouping several orders so their items can be picked in a single trip.
- Slotting
- Slotting is the process of assigning products to storage locations to improve picking speed and space use.
- Graph model
- A graph model represents warehouse locations as nodes and travel paths as edges so routes can be analyzed mathematically.
Common Mistakes to Avoid
- Minimizing aisle count instead of distance is wrong because fewer aisles can still mean longer travel if the route includes long backtracking paths.
- Ignoring the starting and ending locations is wrong because a route that looks short between picks may be inefficient when the packing station or depot is included.
- Treating all items as equally important is wrong because high-demand products should often be placed closer to packing areas to reduce repeated travel.
- Using a fixed route when conditions change is wrong because blocked aisles, priority orders, and inventory moves can make the original path inefficient or impossible.
Practice Questions
- 1 A picker follows a 420 m route at an average walking speed of 1.4 m/s. How many seconds does the travel portion of the pick take?
- 2 An old pick route is 680 m and an optimized route is 510 m. Calculate the distance saved and the percent improvement.
- 3 A warehouse has one packing station at the front and fast-moving items stored at the far back. Explain how slotting changes could improve pick path efficiency without changing the routing algorithm.