Selecting the Best Robotic Tooling Option

5. Will your system be able to adapt to future packaging changes?

Whenever possible, design flexibility into your system to handle changes in your current product line and the addition of new packaging types in the future. Partner with an experienced palletizing integrator to help you make informed choices and specify the equipment best suited for your application.

Tooling Types

Tooling types for palletizing include vacuum, side clamp, fork style and layer handling.

Vacuum tooling is the most popular, yet most misapplied, tooling type. It uses pneumatically actuated cups or foam to lift products, depending on the availability of the surface. As only the top surface of the case comes in contact with the tooling, the vacuum option enables a large range of pallet patterns and is the most prevalent type used for depalletizing. Vacuum tooling is suitable for sturdy, traditional packaging, such as sealed corrugate cases that can bear the total weight of the product during transfer. This method is not recommended for many types of packaging, including tall cases with a low center of gravity. As the robot accelerates, inertia can cause the cases to peel away from the vacuum carrying surface. If not planned for during the design phase, this issue can cause a lot of trouble when it is time to run production.

Fork-style tooling uses a row of forks that comb through conveyor rollers to lift product from the bottom. Forkstyle tooling is useful for handling irregularly shaped cases and bags, cases with lids, fan-fold cartons and any packaging that cannot support its own product weight. On the downside, fork style requires additional space for pattern formation. A large amount of mechanical motion makes this the slowest method, and it is not suitable for depalletizing.

Side-clamp tooling is often used for packages that cannot be handled with a vacuum tool. A robotic palletizer equipped with side-clamp tooling permits shrink-wrapped product in trays or on pads, for example, to be manipulated efficiently. It also enables higher robotic arm speeds than vacuum tooling and provides greater control and confidence when holding and transferring product. Side-clamp tooling works well with thinner-walled sustainable packaging, and can offer flexibility for packaging lines that run a variety of products. For example, a small beverage line is able to clamp a six pack differently than a three-pound box of syrup. However, this type may not be suitable for palletizing fragile items or packaging materials with less tear strength than breach strength (think of a bowling ball in a plastic bag).

Some operations may require complete layer handling for palletizing, which is expensive due to the ancillary material handling equipment needed to form each layer. This application is suitable for cases without sealed tops.

Sometimes, a combination of two separate robotic tooling types is used to help constrain motion along both the x and y axes. Hybrid tooling can also include peripheral tooling for handling pallets or tier sheets. When clamps cannot transfer force to the center of the layer due to overpopulation of product or varying patterns, vacuum tooling can be used to hold the layer in place vertically. Vacuum-assisted layer handling is suitable for patterns that include voids for cooling purposes in pasteurization or heat-curing operations.

With vacuum-assisted fork style, forks support the packages from underneath, while vacuum tooling along the back row of the cases keeps them in place.

Clamping-assisted vacuums are used for tall and light packages. The vacuum tool lifts and moves the product, while the clamps keep it from moving horizontally and peeling away from the vacuum.

Finally, cylinder-mounted vacuum cups can be used as peripheral devices to pick up tier sheets. A set of pick arms swings into position to pick the pallet and then swings back out of the way during the palletizing operation.

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Earl Wohlrab is operations manager for Intelligrated’s robotics group and is responsible for the engineering and estimating of all systems featuring Alvey robotic palletizers and depalletizers. He is an expert in developing palletizing systems for consumer, food and beverage markets.