Avoiding plastic when palletising

Founded in 1958, UFA is a Swiss manufacturer of compound feed, mineral salts and milk powder. When a new bagging system was purchased for its specialty plant in Sursee, Switzerland, in 2018, the company needed to decide if the pallets should be glued again or shrink-wrapped in plastic film.

The company had previously investigated how to avoid plastic when palleting their feed sacks and opted for the AntiSlip Gluing solution from Robatech in 2008. The contact-free hot melt spray application is designed to run reliably and ensure transport safety without plastic film.

With worldwide focus on avoiding plastic, this was reason enough for the company to equip its new bagging system again with AntiSlip Gluing.

At the new bagging plant, 500 bags per hour are filled, sewn and labelled. For subsequent palletising, two AX-Diamond spray heads apply four hot melt spirals to the surface of the passing feed sack without contact. After that, a robot stacks layers of three sacks each on the pallet. Once two layers are stacked, a lift moves the pallet upwards and briefly presses the sacks against a press plate. This increases the adhesion between the layers, and the finished palletised stack can then be transported safely. Each layer is pressed, with the product counter of the Robatech application system ensuring that the last three sacks remain without adhesive application.

The delivery of palletised goods for animal feed preparation results in more than 2 tons of plastic film that must be disposed of yearly at the specialty plant. The gluing solution avoids passing on the plastic to the customers in the first place.

Urs Steiner, Head of Production at UFA Sursee, paid particular attention to a straightforward clarification: “We inquired within the company, and the decision was clear for hot melt adhesive application. Shrink-wrapping would require more effort, space and, assuming a throughput of 25,000 pallets per year, higher material costs. Our customers must already dispose of the feed bags. They would then still have piles of film.”

Flexibility through modularity

UFA produces in a two-step process. In the mixing plant, the delivered powdery substances are weighed in batch mode, mixed homogeneously and stored in a silo. In the next step, the powdery mixture is continuously blown from above into a spray tower and free-fall enriched with hot fat, which is sprayed laterally. The cold air introduced from below creates a crystalline, flowable product.

“With the new bagging system, we have been able to increase from eight to ten layers. That is a logistical advantage,” Steiner said. “However, not only did the gravity-controlled pallet rack have to be modified, but the existing adhesive application process had to be adapted as well. In the past, we just glued on one side. That worked well. With the increase to ten layers per pallet, we had to increase the stability.”

Robatech then equipped the existing Concept melter with two next-generation AX spray heads.

“Thanks to the high backward compatibility and the modular design of the Robatech products, that was no problem at all,” Steiner recalled. “Beyond that, with the CoolTouch insulation on the Diamond application heads, you no longer have to burn your fingers. The energy efficiency is much better because the insulated application heads guarantee consistent adhesive temperature.”

Reliable gluing quality is crucial for safe palletisation and straightforward de-palletisation. After all, the bags should arrive at the customer undamaged and be easily removed without tearing.

Steiner sums up his experience with the pallet stabilisation solution from Robatech: “We are very pleased with the AntiSlip Gluing solution. The process is an excellent solution for us, for our customers and for avoiding plastic waste.”