A machine that removes products or layers from a loaded pallet, often feeding empty containers or cases onto a production or packing line.
Detailed Definition
A depalletizer takes a full pallet and removes its contents, usually layer by layer, so the items can enter a conveyor or production line. Beverage, food and consumer goods plants commonly use them to feed empty cans, bottles or cases to filling lines, and some distribution centers use them to unload incoming pallets. Designs include layer sweep machines and robotic units with vacuum or clamp grippers. Most also handle the empty pallet and any tier sheets. It is the reverse of a palletizer.
How depalletizers handle a load
A common design raises the loaded pallet on a hoist until the top layer is level with a discharge table, then sweeps or pushes that layer off onto a conveyor. The machine removes the tier sheet, lifts the next layer into place, and repeats. Robotic depalletizers use a camera or sensors to locate cases and pick them with vacuum or mechanical grippers, which helps with mixed or less uniform loads.
When the pallet is empty, it is moved out, often to a pallet stacker or dispenser for reuse.
Pallet and load requirements for automated unloading
- Consistent pallet dimensions and good condition, because broken boards or protruding nails can jam conveyors.
- Squared, evenly built layers with the pattern the machine expects.
- Tier sheets that are present where the machine is set up for them.
- Load wrap that can be removed cleanly before the machine starts.
Plants that receive pallets from many suppliers often write a pallet specification for incoming material so the depalletizer runs without stoppages. Rejected pallets are usually unloaded by hand, which costs labor and time on the line.
Related Glossary Terms
Frequently Asked Questions
What pallet issues most often stop a depalletizer?
Problems usually come from inconsistency: pallets of the wrong size, missing or broken bottom boards, protruding nails, loads that lean or shift, and wrap or straps left on the load. Each of these can stop a conveyor or cause a layer to fall. Agreeing a pallet and load specification with suppliers, and checking incoming pallets at receiving, is usually the most effective fix.
Can a depalletizer handle mixed case loads?
Traditional layer sweep machines work best with uniform layers of the same item. Mixed loads with different case sizes are more difficult and are often handled by robotic depalletizers that use vision systems to identify and pick individual cases. Throughput and reliability depend on how varied the cases are, so suppliers usually test with real sample loads before a system is specified.