Flexographic printing is one of the most important processes in packaging printing. Especially for flexible packaging solutions such as films, bags or carrier bags as well as smaller quantities and continuous print images, the modern letterpress process ensures optimum printing results with high cost-effectiveness. Sleeve systems have established themselves as printing form carriers. Sleeves are rubberized, thin-walled sleeves into which the print motif is engraved using a_{CO2 laser}. They are mounted on the forme cylinder mandrel of the printing press and fixed in place using compressed air. Compared to complete printing cylinders, the use of sleeves offers significant advantages such as faster roller cover changes, shorter set-up times and more flexible use of the machines (different sleeve designs can be used on the same forme cylinder mandrel). The low weight of the sleeves also makes handling and transportation easier. Another plus: sleeves are stored vertically. This saves storage space and costs.

Storing flexo sleeves properly and close to production
Proper storage close to production is made possible by innovative solutions such as the "Columba Sleeve Warehouse" from Bauer. "The wide variety of different orders in terms of size, width and other technical parameters requires a large number of different sleeves close to the printing machines," explains Martin Siebold, Managing Director of Bauer, adding: "Our Columba Sleeve Warehouse offers quick access and professional warehouse management and, thanks to its modular design, can be individually adapted to the customer's requirements and conditions on site." This has also convinced a flexographic printing company in the USA. Bauer has implemented a modern sleeve storage system for the storage of flexo sleeves with a length of 1.40 to 1.78 meters, a diameter of 18.3 to 21.6 centimeters and a weight of 13.6 to 31.8 kilograms.

The sleeves are fed in and out via a three-axis system. Bauer has therefore equipped the Y-axis, which is responsible for the precise positioning of the Z-axis, with a linear axis from Rollon. "We have been using Rollon products for a long time," says Siebold. As a specialist in linear motion systems, Rollon is familiar with the requirements of machine and plant construction and supplies modular automation components as well as the necessary application expertise for setting up multi-axis systems in pick-and-place applications. Based on its portfolio of different telescopic rails, linear guides and linear axes, the full-range supplier implements flexible and economical handling solutions - individually designed and precisely tailored to the respective application.

Precision with large spans and heavy loads
A grease-free system with a stroke of 7,000 millimetres, a total length of 8,200 millimetres and a load of 300 kilograms was required for the Y-axis of the sleeve bearing for the US printing company. Due to these requirements, Rollon chose a combination of the Tecline and Speedy Rail product families from the Actuator Line. "The Speedy Rail requires neither maintenance nor lubrication, but the profiles are a maximum of 250 millimetres wide. In this specific application, this would have led to excessive deflection due to the high loads and the enormous span width," explains Frank Thomas, Sales Manager Linear Axis/Systems at Rollon. This is where the linear technology specialist benefited from its extensive modular component system. A 360 millimeter wide Solyda profile now serves as the running surface for the Speedy Rail rollers. The prismatic guides made of self-supporting aluminum were specially created for the construction of rigid and lightweight structures and guarantee high dynamics and a high load capacity. Even large loads can be handled with high precision and quietly. "With dimensions of 360 by 200 millimetres, Solyda is our largest portal profile," says Thomas. "We use it for the Tecline PAR/PAS360 - as with the sleeve storage system from Bauer - as well as for the Modline TCR/TCS360 and our largest robot traversing axis, the SEV360-2."

The long cross axle (Y) hangs completely over the products. It is important that no grease drips onto the sleeves. This is where the advantage of the maintenance-free Speedy Rail runners comes into play. As the Solyda profile was used in favor of a higher load capacity and better load-bearing capacity, a drip-off device underneath the more compact Z-axis protects the important flexo sleeves. A gripper is used to remove the sleeves from the storage system and reinsert them. The Tecline axes have a repeat accuracy of plus/minus 0.05 and therefore provide the necessary precision for millimeter-accurate positioning. Power is transmitted via a helical, hardened rack with ground teeth - ideal for bridging long strokes and for use in dirty working environments. The toothing allows for high loads and ensures smooth linear movement. At the customer's request, Rollon prepared the axis in such a way that Bauer was able to assemble the gearbox itself using simple means. The scope of delivery also included energy chains with a channel and corresponding adaptations for connection to the X-axes. as