Depalletising

When palletising, your own plant decides what the pallet looks like. When depalletising, it arrives as the supplier and the transport have left it: shifted layers, crushed cartons, changing layer patterns, slip sheets and stretch film.

Posture adds to this. The top layer is often above shoulder height, the bottom one just above the floor, and every pick reaches forward across the depth of the pallet. The strain changes with every layer – and is least favourable at both ends.

A lift table or pallet lifter keeps the current top layer at working height. A turntable brings the back row to the front. Both improve posture considerably at low cost.

The weight of each pack, however, stays with the person, as does the total over the shift. Where pack weight and frequency together produce a high load, a lifting aid that takes the weight is needed as well. This is assessed in the risk assessment; in Germany the key indicator method for lifting, holding and carrying is commonly used.

The pack decides the gripper. Closed cartons can be picked from above by suction, provided the flaps and the glue carry the load. Sacks need large-area suction cups or a gripper that reaches underneath. Crates and containers are held by form fit at the rim or handle recess, pails and canisters by the handle or neck.

Accessibility matters: on the pallet the packs stand tightly together. A gripper that needs space at the sides cannot reach the middle pieces.

A robot depalletises reliably when packs and layer pattern are known and stable – single-product pallets from your own production are the ideal case. Mixed pallets from changing suppliers call for machine vision and a gripper that copes with many pack types.

Hand-guided depalletising is the answer to exactly that disorder: the operator spots the shifted layer, removes the slip sheet and re-grips – the device carries the weight.