Pallet patterns
Column, interlock, pinwheel, and row patterns compared. How each affects box strength and load stability, plus TI/HI, overhang, and palletizing software.
A pallet pattern is the layout of cases on each layer of a pallet. It also sets how each layer sits on the one below. The pattern changes how much weight the boxes can carry and how well the load holds together in a truck. This page compares the common patterns and explains TI/HI, overhang, and sheets. It also covers the software that builds patterns and how palletizers stack them.
The common patterns
Most patterns fall into a few families. The names vary by maker and software.
| Pattern | How it is built | Main trade-off |
|---|---|---|
| Column (block) stack | Every layer is the same. Each case sits right on top of the case below. | Keeps the most box strength. The load is less stable and needs more containment. |
| Interlock (brick) | Cases change direction or position from layer to layer, like bricks in a wall. | Ties layers together for a more stable load. Lowers box compression strength. |
| Pinwheel | Cases sit in groups around a small open center. The groups turn like a wheel. | Very stable. Leaves a gap in the middle. Often used for square loads. |
| Row or split row | Cases form rows. Each layer may turn 90 degrees, or one row turns. | A middle path between column and full interlock. |
TopTier, a palletizer maker, says a block pattern has “minimal load stability because the vertical seams align between layers.” It says a pinwheel “arranges cases around a central open space, creating a highly interlocked and stable load” (TopTier).
Strength versus stability
A corrugated box carries most of its load at the corners. In a column stack, corner sits on corner. In an interlock, the load moves from the corners to the weaker side walls. A Virginia Tech thesis reviewed past studies on this. It says the strength loss from interlocking “is be estimated to be between 35% and 55%, depending on the specific conditions” (Molina, Virginia Tech, 2017, p. 27).
Stability pulls the other way. The same thesis says “Columnar stacks tend to generate unstable unit loads and require additional containment methods.” Stretch wrap, strapping, and tie sheets are common ways to add containment. The thesis says interlocking could let you spend less on that material.
The thesis also tested pallet bending. Interlocking the layers cut pallet deflection by up to 53% versus column stacking. The effect was larger on less stiff pallets.
So the choice depends on the product. Heavy or tall loads in weak boxes may need a column stack and more stretch film. Light or short loads may do better with an interlock. If an interlock crushes the bottom boxes, the load can still fail. Test both on real loads.
TI/HI
TI/HI describes how many cases go on a pallet. TI (tie) is the number of cases on one layer. HI (high, or tier) is the number of layers. GS1 Canada’s guide gives a 10 × 4 example: 10 cartons per layer and 4 layers (GS1 Canada). That works out to 40 cases per pallet.
Your customers use TI/HI to plan their racks, trucks, and orders. Send them the same TI/HI that your palletizer builds. GS1 Canada warns that wrong pallet data “can cause significant business challenges.”
Overhang and underhang
Overhang means cases stick out past the pallet edge. The box corners lose support. A Virginia Tech study for the Fibre Box Association tested over 1,600 boxes. It found that overhang “could be between a 0% and 40% reduction” in box compression strength (Molina and Horvath, Fibre Box Association, 2024). The report says the Fibre Box Handbook estimates the loss at 20% to 40%.
The study’s Phase 2 tested overhang from 0.25 to 3.25 in. on one side or on two sides. It built a model to predict the strength left in the box. It found that box height and the board’s ECT (edge crush test) value had no significant effect on the loss, within the ranges tested.
Underhang means the load is smaller than the pallet. The boxes keep full corner support, but the pallet is not fully used. Decide with your customer how much overhang or underhang they accept.
Pallet sizes
ISO 6780 lists six standard pallet sizes. The North American ones are 48 × 40 in. and 42 × 42 in. (Molina thesis, p. 11). The thesis says the Grocery Manufacturers Association (GMA) introduced the 48 × 40 in. size. It made up 24.4% of new wooden pallets built in the US in 2011. The 42 × 42 in. pallet is the second most used in the US, mostly by the plastics industry.
Pallet dimensions are listed as length by width. The length is the stringer length. The width is the deckboard length. Make sure your pattern tool and your customer use the same order.
Load height and weight
Your customer, carrier, or warehouse sets the maximum load height and weight. Check their routing guide before you set HI. Also check your downstream machines. Lantech rates its Q-300 stretch wrapper for loads up to 80 in. high and 4,000 lb (Lantech). See the stretch wrapper guide for more models.
Labels out
Labels out means every case label faces the outside of the load. People can then scan or read cases without breaking the pallet. The palletizer must turn cases to do this, so the pattern has to plan for it. Columbia lists “Labels-out stacking” as an option on its HL6200 palletizer (Columbia HL6200 cut sheet).
The pallet label has its own rules. The GS1 Logistic Label Guideline says pallet barcodes “SHALL be positioned between 400 millimetres (16 inches) and 800 millimetres (32 inches) from the base of the pallet.” It recommends labeling two sides of each pallet (GS1, section 8.1).
Slip sheets, tier sheets, and caps
Sheets add stability and protection. The names overlap, so agree on terms with your supplier.
- Tier sheet (also called a tie sheet, layer pad, or divider sheet). It goes between layers. ORBIS, a maker of plastic tier sheets, says they “provide maximum product protection and load stability” (ORBIS). ORBIS lists a standard footprint of 44 × 56 in.
- Slip sheet. Toyota Forklift describes slip sheets as “thin sheets made of plastic, paper, or corrugated material.” A load on a slip sheet can ship with no pallet. A forklift with a push/pull attachment “clamps onto the sheet and pulls the sheet and product load onto the platens” (Toyota Forklift). Many plants also use the term for a sheet laid on the pallet under the first layer.
- Cap sheet. It goes on top of the load.
Columbia lists a “Slip / Tie / Cap sheet dispenser” as an HL6200 option. Robot cells can place sheets too. For sheet dispensers, see the palletizing conveyor guide.
Pattern software
Pattern software takes your case size, case weight, and pallet size. It then lists patterns that fit and how full the pallet is. Some tools also check stacking strength. The Molina thesis names CAPE and TOPS as “the most popular commercial softwares” for this, citing Twede and others (2014).
| Tool | Who makes it | What it does (per the maker) |
|---|---|---|
| TOPS Pro | TOPS Software | “Automatically Generate Layer, Alternate Patterns.” Has a “Stacking Strength Analysis” and lets you “Add Slip Sheets, Straps, Caps.” |
| Cape Pack | Esko | “Calculate multiple pallet patterns” from a fixed case size. Cloud-based, with case and pallet workflows. |
| OnPallet | Lorenz Pan AG | A free online calculator. You enter case and pallet sizes and press “Calculate.” It lists a 40 × 48 in. pallet. |
| PalletTool and PalletPRO | FANUC | PalletTool runs on the robot. It lets operators “create and modify unit loads directly from the Tablet TP right on the floor.” PalletPRO is a PC plugin with a “built-in library of industry standard patterns.” |
| Robotiq palletizing software | Robotiq | Runs on its cobot palletizers. Robotiq says “teaching a new SKU takes one minute.” |
FANUC says PalletTool 3 also has a drag-and-drop pattern builder and “automatic pattern generation works from basic box dimensions” (FANUC Tech Transfer).
A pattern that fits well on screen can still fail in a truck. Run the best two or three patterns on real loads. Then ship them and check how they arrive.
How palletizers build patterns
A conventional palletizer builds one whole layer at a time. Cases come in on a conveyor. Turning devices spin cases to the right angle. The machine forms rows, pushes rows into a full layer, and sets the layer on the pallet. Columbia calls its HL6200 “the fastest row forming palletizer in the industry.” It rates the machine at “up to 120 cases per minute (depending on pattern).” New patterns are set up on its Product Manager HMI (the operator touch screen). See conventional models and speeds.
A robotic palletizer places one case or a few cases per pick. Each case goes to a programmed spot and angle. So a new pattern, including labels out, is a program change. Across its palletizer line, Robotiq lists “up to 13 cycles per minute” and “a payload of up to 77 lb (35 kg).” It does not tie those figures to one model. Its PE20 is rated for “18 kg (40 lb).” See robotic palletizer models and cobot cells.
A cobot (collaborative robot) is not safe just because of its name. Its collaborative status comes from a risk assessment of the whole application, under ISO 10218-2:2025 and ANSI/A3 R15.06-2025. The 2025 editions now include the collaborative guidance that used to sit in ISO/TS 15066. See the risk assessment steps.
All speeds on this page are makers’ rated speeds. Real output depends on your cases, pattern, sheets, and pallet changes. For mixed loads with many SKUs per pallet, see mixed case palletizing.
Common questions
Column stacking keeps more of the box strength, because each corner sits on a corner below. A Virginia Tech review puts the strength loss from interlocking at 35% to 55%. Interlocking makes a more stable load. So column loads usually need more stretch film or other containment.
TI is the number of cases on one layer. HI is the number of layers on the pallet. A TI/HI of 10 × 4 means 10 cases per layer and 4 layers, or 40 cases per pallet.
A Virginia Tech study for the Fibre Box Association found a 0% to 40% loss in box compression strength, depending on how far and on which sides the box hangs over. The Fibre Box Handbook estimate is 20% to 40%.
Packaging teams use tools such as TOPS Pro, Esko Cape Pack, and the free OnPallet calculator. Palletizer makers also ship their own pattern tools, such as FANUC PalletTool and PalletPRO and the Robotiq pattern setup. See robotic palletizer cells for the machines.
The 48 × 40 in. pallet, introduced by the Grocery Manufacturers Association (GMA). It made up 24.4% of new wooden pallets built in the US in 2011, per a Virginia Tech thesis citing Bush and Araman.