Linear bearings for simple filling level adjustment in folding and gluing machines

• What was needed: drylin® W linear rails, drylin® T profile rails, drylin® SLW spindle linear tables
• Requirements: Uncomplicated format adjustments, robust and maintenance-free components that have to work lubrication-free due to the cellulose in the air
• Industry: Packaging industry
• Success for the customer: The lightweight and lubrication-free plastic creates flexible system modules. The drylin® linear technology also works reliably over the long term in two and three-shift operation.

One of the focal points of Bernhardt Maschinenbau oHG is the construction of folding and gluing machines. These are suitable for processing materials between 180 g/m² and 600 g/m². The machines can be used, for example, to fold and glue CD sleeves, digi-packs, folding boxes, flight ticker pockets or presentation folders at a speed of up to 300 m/min. Thanks to its modular design, additional application and dispensing systems can also be connected at a later date and used flexibly. The manufacturer is quick to respond to customer requests, for example, it now offers a fast filling height device with an output of up to 5,000 cycles per hour. A prototype system for 250,000 cartons was built, which machine operators must be able to adjust quickly and easily to new requirements. The environmental conditions are not always easy either. This is because paper contains cellulose. The omnipresent paper dust can quickly combine with air humidity to form a sticky mass that could lead to malfunctions in the process. Robust and, above all, maintenance-free technology is therefore essential.
In order to avoid production downtimes and unnecessary stoppages of the folding and gluing machines, high demands are placed on the machine elements used. Freedom from maintenance and lubricants, insensitivity to dirt, a long service life and, of course, cost-effectiveness play a very important role.

The company relies exclusively on drylin® linear plain bearing systems in the adjustment units of the special attachments. As the machine frames are not always in one place at the customer's premises, the comparatively lightweight material plastic scores highly in contrast to steel guides. It also looks good. The system profiles are the same in all folder gluers. The aluminium frames and the aluminium rail material of the drylin® linear bearings harmonise in shape and colour. Another decisive factor was the price, which convinced the system manufacturer just as much as the cleanliness of the lubrication-free bearing, which prevents soiling of the product in the machine.
Even at maximum capacity utilisation in two and three-shift operation, the systems now run smoothly. Flexible drylin® W guide systems with a linear spindle or combined as a compact lead screw linear system drylin® SLW are used in the filling level equipment. In addition, robust drylin® T linear guideways prove their strength. The material iglidur® J has proven itself in all cases. It was specially developed for linear applications in conjunction with hard-anodised aluminium surfaces.
In a very recent project, a silicone paper dispenser, the drylin® W is also proving its worth. The dispensing system can apply up to 10,000 siliconised paper strips per hour with precise positioning. The dispenser is installed in folding carton gluing machines, for example, and is used for the production of cardboard mailing envelopes. With a maximum space requirement of 10 mm, a large number of axes are fitted with the linear plain bearings. With them, the required speeds of 40 m/min, which can be extended to up to 150 m/min, can be easily realised over very short distances.