Clever Packaging, Simple Machines

With help from Rexroth and its GPC pneumatic cylinders, it is now able to do all of this and more.

The innovative design of Ecolean bags makes them free-standing, stable, and easy to handle. They compact once disposed of and comprise of environmentally friendly materials. Furthermore, the bags do not require any complex machine technology in contrast to carton packaging. This unique packaging solution also enables simple construction of the machines, which are fast, reliable, low-maintenance and only have to be operated by one worker.

Ecolean developed this packaging concept, starting with the special material Ecolean Calymer™ which consists of approximately 40 percent calcium carbonate (natural chalk) and polymers as the binding agent. Fully adapted to modern packaging, the company which is located in Helsingborg, Sweden, offers application specific production lines with filling and packaging stations for liquid products.
Whether a large company or small operation, each customer receives pre-finished, printed packaging on reels that corresponds to their specifications. These reels then have to be simply placed in a ready-for-operation machine. The packaging is delivered as hygienic, hermetically pre-sealed reels and inserted in the machines. Each package is then slit open at the top edge. In Ecolean’s LeanAir (LA) packaging, which has two chambers, one of which serves as a stabilising handle, the liquid product is first filled into one chamber and, in the second step, air goes into the handle. Ecolean’s 1-chamber LeanBase (LB) packaging is simply filled with the liquid product. The finished packed goods are ready for shipment after sealing and the entire process only takes 2.4 seconds. The extremely short filling time and hygienic packaging ensures the same quality as that of the product inside.

“The majority of our customers are dairy operations and have, of course, their own special environmental requirements,” explains Christian Olsson, Technical Product Manager at Ecolean. “This is why we need components that can withstand factors such as cold, humidity, and splashes from the liquid products. This mainly applies to the pneumatic cylinders used. Previous cylinders caused problems due to the many holes in the cylinder housing that could be quickly affected by splashes as well as internal guidance that was too weak, so we looked around for another solution.”

Working in close cooperation with Ecolean, Rexroth developed the GPC Clean pneumatic guide cylinder. The technical data corresponds to that of a “normal” cylinder only at first glance: working pressures from 1 to 8 bar, cylinder diameters from 10 to 63 millimeters, ball or friction bearings and magnetic pistons. However, the GPC guide cylinder only comes into use when the performance of common cylinders is no longer sufficient and, for example, resistance to transverse forces, precision, and a non-rotating function all play a large role. These criteria were also essential for application as carriers of mechanical grippers at Ecolean.

“The Rexroth pneumatics assisted us with fine-tuning once we had constructed the first machine. The cylinders we use today were not available in the Rexroth program during our machine development phase.” In the meantime, Rexroth provides the cylinders for a majority of the Ecolean machines, along with a plate that can be directly mounted to hold four tools. “This of course saves us assembly time, as we receive both components as a plug-and-play unit.”

The GPC Clean is reliable due to its anodised aluminium housing and guide bushings that can withstand even the most intensive cleaning, which is almost never required. The surface is completely smooth and has no obstructive grooves or holes, making it ideal for applications in the food sector involving product splashes, as the liquid products are unable to penetrate the cylinders.

Ecolean uses the GPC Clean series of pneumatic cylinders in all Ecolean EL1 and EL2 machines that work with container sizes between 200 millilitres and one litre, with or without an air chamber and a standard deviation of 3 millilitres. Ecolean requires a fast guide cylinder, particularly in its sealing unit. Design Engineer Rasmus Johansson explains the reason for this: “The last millimetres of the stroke are especially important, as perfect package sealing is only possible with absolutely exact controlling. This is ensured by the high precision of the GPC Clean.”

Not only does Ecolean place great importance on the environmentally-friendly characteristics of the packaging, but the noise level of the machines is kept as low as possible. Sebastian notes, “The pneumatic cylinders have air cushioning and run very quietly. All this has a positive effect at the workstation.” Additionally, this air cushioning prevents vibrations in the machine, making the components less susceptible to wear and resulting in longer service lives for the cylinders.

In contrast to the desired convenience of cushioning, Ecolean purposefully abstained from a cylinder adjustment function. Rasmus Johannsson explains, “We wanted to do away with any potential sources for user error and thus make the machines easy for anyone to operate. To accomplish this, we rely on a fixed cylinder that is adjusted once at the factory and then remains unchanged, ensuring smooth function.” The packaging machines can be set up very easily, since the complexity is actually in the packaging itself. Christian Olsson sums up that it is also a question of cost efficiency: “Customers can repair our machines or exchange parts themselves. This makes the packaging concept appealing for small as well as for large operations.”