Summary (TL;DR)
Mixed palletization is the process of building pallets from many different SKUs. Doing this manually is slow, error-prone, and physically exhausting. As SKU counts, service expectations, and compliance requirements increase, warehouses need support beyond manual judgment. There are four main ways to perform mixed palletization: fully manual, system-guided (software-only), system-guided with robots (AMRs/AGVs moving pallets), and fully automated robotic systems. Choosing between them depends on volume, complexity, labor situation, and how much guidance or automation is needed to gain consistency, protect workers, and control costs.
What is Mixed Palletization
Mixed palletization (or mixed-case palletization or mixed SKU palletization) is the process of building a pallet made of different SKUs, each with its own size, weight, crush limit, and handling rules. Mixed-case palletizing is something most warehouses do constantly.
It is common in store order fulfillment, LTL shipping, E-commerce and omnichannel fulfillment and 3PLs serving multiple clients.
Humans are naturally strong at spatial reasoning and applying rules on the fly. That is why experienced operators can handle mixed pallets effectively while considering:
- Will this crush what’s underneath?
- What’s coming next - something heavier? Something fragile?
- Will the pallet be stable enough to survive transport?
However, making those decisions for eight hours a day, while walking long distances, lifting, and moving heavy cases, inevitably introduces errors and inefficiencies. The result is:
- Longer pallet-building times due to excessive walking
- Lower picking productivity
- More product damage and higher transport costs
- Physically punishing work that becomes harder as SKU counts rise
This is why some form of assistance in mixed palletization has shifted from “nice to have” to essential.
In this article we look at the 4 types of performing mixed palletization and it can be supported.
4 Types of Mixed Palletization
1. Fully manual mixed palletization
During fully manual mixed palletization operations operators walk the warehouse, pick cases, and build pallet using their own judgment.
Fully manual palletization requires very low investment and technical overhead. Operators are more flexible and can handle exceptions easier, however this comes at the cost of long walk distances and higher risk of product damage and unstable loads. Manual palletization scales poorly in complexity and volume.
At some point, adding more people no longer fixes the underlying problems.
Who’s it for:
- Small to mid-size warehouses with limited SKUs and volumes and relatively low labor costs and modest service pressure
- Sites with low rotation among operators in order to avoid frequent onboardings
2. System guided mixed palletization
In system guided mixed palletization operators are supported in pick route optimization and pallet building/stacking sequence through software.
This support can be communicated through 2D or 3D stacking instructions on handhelds or tablets. Operators still walk, pick, and place cases, but they follow clear on-screen guidance instead of relying purely on memory and tribal knowledge.
New workers can follow visual instructions instead of spending months to reach productivity standards. This also reduces risk when working with temporary staff.
System-guided palletization treats picking and pallet building as a single optimization problem. A pallet will not be stable if operators simply pick what is closest. The logic must consider weight, size, orientation, fragility, and sequence at the same time:
- If you optimize for the shortest route, the pallet build suffers
- If you optimize for pallet builds, the walk time grows
Warehouses need to scope and quantify the trade-off at the start to set the project up for success. Warehouse optimization software providers like Optioryx are designed to handle exactly this kind of combined routing and pallet-building problem.
Compared to robots or large automation, software-guided palletization requires very little or no capital, devices, integration, and training.
It is easier to pilot, roll out, and adjust. Once the logic and integration are in place, replicating the solution to another warehouse is mainly a matter of configuration and training, not construction.
Who's it for:
- Medium to large DCs with high SKU counts and complex orders
- Retail and e-commerce operations with strict compliance requirements
- Sites where retaining operators is difficult and labor shortages are severe
3. System guided mixed palletization with robots
System-guided mixed palletization with robots keeps the same brains (with software algorithms and 2D/3D guidance) but changes the muscle for pallet movement. Autonomous mobile robots (AMRs) or AGVs carry the pallet between pick locations while operators pick and stack with visual guidance on the robot’s screen.
This approach leads to significant reduction in pushing heavy loads, however requires a much higher capital expenditure than software-only solutions.
Robots work best on top of strong system guidance. Without good algorithms and clear instructions, they risk becoming expensive, moving bottlenecks.
Who’s it for:
- Medium to large DCs with high picking volumes
- Operations with stable product dimensions and packaging
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4. Fully automated mixed palletization
At the top end of the automation ladder is the fully automated palletization cell. During fully automated mixed palletization conveyors feed cases to robotic or gantry palletizing cells. Algorithms decide case sequencing and robots build pallets automatically.
Fully automated systems can be extremely effective in the right context, but they are typically viable only for large, stable, and well-capitalized operations.
Who’s it for:
- Warehouses with very high throughput and consistent output quality
- Highly repeatable pallet patterns
- Predictable labor requirements
Comparison Table: Manual vs Semi-Automated vs Fully Automated
Why Mixed Palletization Has Become Harder
- SKU explosion: More flavors, pack sizes, and packaging formats.
- Omnichannel and e-commerce: Smaller orders, more frequent shipments, and tighter lead times.
- Retail and customer compliance: Strict rules on labeling, pallet height, weight distribution, and sequence.
- Labor shortages and ergonomics: Fewer experienced operators available, and higher focus on safety and fatigue.
- Rising service expectations: High on-time delivery, near-zero damage, and consistent quality.
In this environment, relying purely on manual palletization is increasingly risky. At the same time, going straight to full automation is often too expensive, too rigid, or simply unnecessary.