What Is Mixed Palletizing?
Mixed palletizing, also known as mixed-case, mixed load, or mixed SKU palletizing, is the process of arranging products, each with unique sizes and shapes, onto a pallet for shipment. This practice accommodates varied consumer preferences and optimizes the shipping and handling process.
Mixed Case Palletization in Logistics
There has always been a need to build pallets consisting of different SKUs. This is particularly evident in the beverage and food industry, where warehouses handle various types of SKU cases in different sizes and characteristics, such as cans, plastic and glass bottles, tetra paks, and kegs. With retailers seeking to offer a wide variety of choices to their consumers, distributors are tasked with meeting this demand.
Mixed palletizing is commonly employed for B2B shipments, such as "replenishments" to small shops. In this scenario, the shop purchases multiple products, but not in full-pallet quantities. This form of palletizing helps warehouses manage a variety of items, like beverages, industrial supplies, or pharmaceuticals, all in one shipment, streamlining order fulfillment.
Why Manual Palletizing Struggles
A pallet won't be stable if operators pick what's closest. You need rules in the logic: weight, size, orientation, fragility, and sequence.
Typically warehouses handle mixed palletizing during pick and pack operations. During a pick tour, workers receive a list of all the picks that need to be made and placed from racks and shelves and arrange them directly onto pallets, along with the warehouse location next to every SKU. Case picking is often part of this process, where individual cases or cartons of products are selected and placed on pallets.
Experienced pickers, with over six months of experience, often rely on their knowledge of how products look and which SKUs would form the first layers of the pallets. However, on average, it takes a new picker 2-3 months to achieve the productivity levels of an experienced picker. Despite this, warehouses are increasingly relying on temporary warehouse workers with high turnover rates. For inexperienced pickers, this task becomes very complex, leading to 2 errors:
- Bad Stacking: When pickers are given a list of items that need to be picked, they use intuition & expertise to place the items on pallets, leading to unstable loads.
- Long Walking Distances: Pickers will choose picking paths having to consider various parameters such as weight & size of each SKU, stackability of SKUs, and SKU location, which leads to long pick paths due to the complexity of the task.
The manual way leads to inconsistent pallet builds and product damage. This type of palletizing quickly reaches its limits in terms of accuracy and efficiency.
WMS logic vs Optimization Layer
A WMS assigns orders, locations, and confirmations. It does not jointly optimize route, placement sequence, and physical constraints. It cannot reconcile distance, stability, and fill in one plan. Guided execution does: provide operators with the plan for the shortest path and show simple 2D top-down build steps.
This is what mixed-case palletizing does, it links two tasks. Picking and pallet building are one problem. Treat them together.
The core trade-off
- If you optimize for the shortest route, the pallet build suffers
- If you optimize for pallet builds, the walk time grows
Aim for the shortest feasible path that preserves a stable build.
Biggest gains we see
- Faster onboarding for new and temporary workers
- Fewer damages from unstable stacks
- Less rework when pallets leave the aisle
