Ti and Hi on a Pallet: What the Two Numbers Mean for a Palletizer Layer Program

Ti is the number of cases in one pallet layer. Hi is the number of layers. For a load with the same case count on every layer, Ti × Hi gives the total cases per pallet. Neither number tells a palletizer where to place those cases.

The terminology follows the glossary on page 24 of the GS1 US data-quality framework, a dated reference used here for definitions. Translating that shorthand into a machine recipe requires a layer drawing, a layer sequence and the conditions for ending the load.

Read the count before interpreting the pattern

Assume, solely for illustration, six identical cases per layer and four complete layers. The count is 6 × 4 = 24 cases. The diagram separates the plan view of a layer from the stack’s layer count; it does not prescribe case dimensions, support or pallet capacity.

Two layer layouts can have the same Ti while using different orientations or label-facing directions. A Hi of four describes a count of layers, not a height in inches or millimeters. Keep dimensional information in separate recipe fields with explicit units.

Translate Ti and Hi into a layer program

Use Ti as a count to reconcile against the approved layer drawing. Use Hi to reconcile the programmed layer sequence. Our suggested handover record is:

Recipe input	What the integrator needs beyond Ti and Hi
Product identity	Case drawing revision, filled dimensions, mass and permitted orientation
Layer geometry	Position and orientation of every case, pallet datum and label-facing requirements
Layer sequence	Which pattern runs at each level, including any rotated or interlocking layers
Sheets	Whether a base, intermediate or top sheet is required, and when it is handled
Completion	Target case count, layer count, overall height limit and partial-load rule
Restart	How the controller reconciles a partly completed layer after an interruption

This mapping is an editorial planning method, not a description of a particular controller’s field names. Ask the supplier to demonstrate its implementation.

BW Packaging’s Maximizer description describes cases passing through metering, lane division and layer accumulation before palletizing. That machinery illustrates why a count alone is insufficient: cases must arrive in the order and orientation required to form the intended layer. A robotic cell also needs a placement sequence and a tool path compatible with its pattern.

Where the multiplication needs qualification

Load condition	How to record it
Alternating or interlocking patterns	Identify each pattern and its place in the sequence. Equal counts can preserve Ti × Hi while changing geometry.
Layers with different counts	Add the actual case count for each layer rather than repeating one Ti.
Incomplete top layer	State its case count and positions separately; do not label it a full layer.
Mixed products or mixed heights	Use the actual build plan and SKU quantities; a single repeated-layer shorthand may be inadequate.
Overhang or tight edge clearance	Specify the geometric constraint separately. A case count cannot establish acceptability.

For another illustrative count, three layers of six cases plus a top layer of four contain 22 cases. Writing only “6 × 4” would overstate that load. A sheet between layers changes the height allowance and handling sequence without adding a case to Ti.

Check the load and the machine separately

The NIST mixed-pallet paper evaluates matters such as package support, overhang, pressure and overall load constraints. Its research context reinforces a useful distinction: counting packages does not demonstrate load integrity. Neither this arithmetic nor the schematic establishes stacking strength or safe transport performance.

Have the project team confirm the packaged product, pallet, sheets and finished-load limits against the proposed recipe. Include the pallet and sheet allowances when checking overall height. Then ask the integrator to review the first placement, a pattern transition, the highest placement and an interrupted-layer restart using representative cases.

Keep a separate throughput calculation: Ti and Hi do not describe pick time, sheet handling or pallet exchange. For variable builds, continue with the mixed-case planning guide.

Before approving the layer count, use the palletization meaning and unit-load engineering guide to check the footprint, support and center of gravity behind the proposed recipe.