Slotting ABC Velocity Planner

How this works

ABC velocity slotting says put the highest-pick-velocity SKUs in the nearest storage zone. But "highest velocity" has to be measured, not assumed from whatever tier label a SKU already carries. This engine computes the actual optimal tier-to-zone pairing from the entered pick counts, by the rearrangement inequality, the largest pick count paired with the shortest distance minimizes total travel, rather than trusting that the A/B/C labels already reflect true velocity order.

Key terms

• Optimal pairing: the tier-to-zone assignment that minimizes total daily travel distance, computed by sorting pick counts descending against zone distances ascending.
• As-labeled: the travel result of trusting the A/B/C labels exactly as entered, without checking whether they actually match velocity-descending order.
• Random baseline: the expected travel distance with no slotting strategy at all, every pick equally likely to land in any zone.

Assumptions

• Three velocity tiers, three storage zones, one round-trip distance figure per zone
• One uniform travel speed

Limitations

• Does not model SKU co-location or pick-path sequencing within a zone
• Three tiers and three zones only, not an open-ended multi-zone optimizer

Sources

Frazelle, World-Class Warehousing and Material Handling, and Tompkins et al., Facilities Planning, for the standard ABC/Pareto slotting principle, combined with the rearrangement inequality to prove the pairing is actually optimal.

Worked example

Entered as Tier A 50 picks/day, Tier B 150, Tier C 400, with near/mid/far zones at 40, 90, and 160 feet, the as-labeled layout (A nearest) costs 79,500 feet of daily travel. But Tier C actually has the most picks, the true optimal pairing puts C nearest, B in the middle, A farthest, cutting daily travel to 37,500 feet, less than half. Trusting the labels alone would have missed that entirely.

Common use cases

• Checking whether a warehouse's current A/B/C labels still match actual pick velocity
• Quantifying the travel-time payoff of a velocity-based reslot before committing labor to it
• Continuing from Warehouse Staffing Planner's labor plan into a flow decision
• Feeding a confirmed slotting strategy into Pick Method Comparator's picking-method decision