A pallet shuttle system is a high-density warehouse storage system that uses a motorized cart to move pallets inside deep rack lanes. It matters because it can store many pallets in less floor space than standard selective racking. This is useful in cold storage, food distribution, manufacturing, and any warehouse with many pallets of the same product.
The main goal is to reduce travel inside the rack while increasing storage density and throughput.
Key Facts
- Storage density = stored pallets / floor area, often measured in pallets per m2.
- Lane capacity = lane depth in pallet positions x number of vertical levels.
- Total pallet capacity = number of lanes x lane depth x number of levels.
- FIFO means first in, first out, where the oldest pallet is removed first.
- LIFO means last in, first out, where the newest pallet is removed first.
- Throughput rate can be estimated by pallets per hour = pallets moved / operating time in hours.
Vocabulary
- Pallet shuttle
- A battery-powered cart that travels inside rack lanes to carry pallets between the lane opening and storage positions.
- High-density storage
- A storage method that places pallets close together to maximize capacity within a given warehouse area.
- Storage lane
- A deep horizontal path in a rack where pallets are stored one behind another.
- FIFO
- First in, first out is an inventory flow rule where the earliest stored pallet is the first one removed.
- LIFO
- Last in, first out is an inventory flow rule where the most recently stored pallet is the first one removed.
Common Mistakes to Avoid
- Counting only floor-level pallet positions is wrong because shuttle racks usually store pallets on multiple vertical levels. Always multiply by the number of levels when finding total capacity.
- Assuming every shuttle system uses FIFO is wrong because some layouts operate as LIFO from one end of a lane. Check whether pallets enter and exit from one side or from opposite sides.
- Ignoring lane depth limits is wrong because very deep lanes can reduce flexibility and increase retrieval time for mixed products. Match lane depth to product volume and turnover rate.
- Treating the shuttle like a forklift is wrong because the shuttle moves only inside rack lanes while forklifts or lifts handle aisle transport. Separate in-lane movement time from aisle handling time when estimating throughput.
Practice Questions
- 1 A pallet shuttle rack has 18 lanes, each lane is 12 pallets deep, and the rack has 4 vertical levels. What is the total pallet capacity?
- 2 A shuttle system moves 96 pallets in 3 hours. What is the average throughput in pallets per hour?
- 3 A warehouse stores frozen vegetables with many pallets of the same product and wants to reduce aisle space. Explain why a pallet shuttle system may be better than standard selective racking, and name one possible disadvantage.