Layer Pattern Comparator

How this works

Column stacking repeats whichever carton orientation fits more per layer, identically every layer. Interlocked, or brick, stacking alternates orientation layer to layer so each layer's seams sit over the layer below's carton bodies, which resists lateral shift, but it has to work with both orientations, so its per-layer count is bounded by whichever orientation fits fewer. A comparison that only looks at cartons per layer will always favor column stacking, since it is never lower than interlocked. This engine weighs that density cost against a stack-height-based stability risk, recommending interlocking once the stack is tall enough that lateral-shift risk outweighs the density loss, or whenever the loss is small.

Key terms

• Column stacking: every layer placed in the same orientation, fitting the higher of the two cartons-per-layer counts.
• Interlocked (brick) stacking: layers alternate orientation so seams overlap the layer below, bounded by the lower of the two counts.
• Cartons-per-layer loss: how many fewer cartons per layer interlocking fits compared to column stacking.
• Column stability risk: elevated once a column-stacked pallet exceeds four layers, since taller unbonded stacks carry more lateral-shift risk.

Assumptions

• Rectangular carton and pallet footprint
• Uniform layer height
• The stability check is a stack-height threshold, not a structural or transport-vibration model

Limitations

• Two named patterns only, not a general pattern-generation search
• Does not account for strapping, stretch wrap tension, or slip-sheet friction, which also affect real-world stability

Sources

Standard unit-load and footprint-packing treatment (Frazelle's World-Class Warehousing and Material Handling, Tompkins et al.'s Facilities Planning), the same footprint-packing approach used in Cartons per Pallet Optimizer.

Worked example

A 20 by 8 inch carton on a 48 by 40 inch pallet fits 12 per layer column-stacked versus 10 interlocked, a 16.7 percent density loss that on its own exceeds a typical 10 percent tolerance. A density-only comparison would pick column stacking. But at 6 layers the stack is past the point where an unbonded column carries meaningful lateral-shift risk, so the correct recommendation flips to interlocked despite the density cost, trading 12 cartons across the stack for a materially more stable load.

Common use cases

• Deciding whether a tall pallet stack needs interlocking for transport stability
• Checking how much cartons-per-layer density interlocking actually costs before committing to it
• Comparing pattern strategy for the same carton and pallet fit already sized in Cartons per Pallet Optimizer