There must be a lot of people wondering about the comparison between the 4-way pallet shuttle and the mother-child shuttle.
In our opinion there is no absolute good or bad solution, only suitable one.
Factor 1: Different warehousing modes
Warehouses with many varieties and small batch sizes, or warehouses with few varieties and large batch sizes, are suitable for four-way pallet shuttle transport. However, the mother-child shuttle is only suitable for warehouses with few varieties and large batch sizes.
Factor 2: Different inbound and outbound strategies
The 4-way pallet shuttle can First-in First-out, but mother-child shuttles cannot. Because it is wasteful to deploy mother shuttles to every peripheral track. But 4-way pallet shuttle can reach any storage location in the warehouse, including every peripheral track.
Factor 3: Flexible attributes
Mother-child shuttles can only run on their own tracks. If a mother shuttle stops working, the goods beside cannot be stocked in and out. If a 4-way pallet shuttle stops working, the system can send instructions to other 4-way pallet shuttle，the warehouse can operate normally. In this point, the mother-and-child shuttle is as inflexible as the crane ASRS.
Factor 4: Efficiency differences
Because mother-child shuttles can only run on their own track, the crane ASRS can only run on a fixed track, the efficiency cannot be maximized. But 4-way pallet shuttle can. When the goods of one floor are centralized in and out of the warehouse, all 4-way pallet shuttles can reach this floor to work.