Linear plain bearings for folding and gluing machines

Filling level packing and laminating

Light, lubricant-free linear plain bearings for folding and gluing machines

Product information is being taken simply from the net more often these days. That also applies to machinery components and purchased parts in order to save process costs. Bernhardt Maschinenbau oHG counts on lubricant and mainteance-free linear plain bearings when designing customer specific folding carton gluing machines.
Configured on the Internet, then technically well advised – a story from the life of a constructor 2010.

Flat built, lubricant-free “drylin® N” guide operating in a filling level attachment.

“One of our main activities is designing folding and gluing machines,” reports Max Steiner, head of design at Bernhardt Maschinenbau oHG in Neunkirchen am Brand. 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 covers, digi-packs, small folding boxes, flight ticket pouches or presentation folders with a speed of up to 300 m/min. Due to their modular construction, there is the option of also connecting additional application and dispensing systems at a later point in time so that they can be used flexibly and variably at any time.

The family business started in North Rhine Westphalia as an industrial agency. Since 2003 it has concentrated on the construction of folding gluing machines, which are used among other things in print finishing. “Our customers come to us with a problem and we then implement their wishes quickly and cost-effectively in machinery terms,” says the head of design in explaining the company philosophy. “Since Drupa 2008, for example, we have been supplying a fast filling level device with a performance of up to 5,000 cycles per second. With a reject rate of maximum three percent, this accessory for folding and gluing machines has hit the market like a bomb. “

Innovative: Entry into 3D gluing

Filling level products are all the rage. This usually involves folding boxes, whose special feature is that they do not have a flat blank and, unlike the so-called assembly boxes, do not have to be assembled in a time-consuming and hence costly manner in an extra process by hand. Moreover, they can be folded, glued and filled in a single pass. “We sold two folding box gluing machines with filling level devices to Russia, which produce 3D boxes for DVDs day and night, seven days a week,” says Max Steiner. Especially in the DVD and CD sector, plastic packaging is increasingly losing its importance due to recycling reasons. Despite or perhaps precisely because of the economic crisis, the print finishing and packaging specialist has noticed that an increasing number of German customers are also venturing towards filling level packaging.

drylin®” trapezoidal leadscrew nut made of the material “iglidur® J” in filling level device with folding pouch.

“In the filling level sector, we started with coin boxes for collectors and built a prototype unit for 250,000 boxes,” says Max Steiner looking back. Technical requirements here are, basically, that the machine user must be able to adjust the units quickly and easily to new requirements. The environmental conditions are also not always straightforward. Because paper contains cellulose. The ever-present paper dust can quickly combine with humidity to form a sticky mass, which could lead to interference in the process. As a result, it comes down to robust and above all maintenance-free technology.

Detailed view of lateral adjustment with spindle nut made of tribologically optimized plastic.

Saving considerable weight with linear plain bearings

In order to prevent production failures and unnecessary downtimes on the folding and gluing machines, high demands are placed on the machine elements used. Freedom from maintenance and lubrication, insensitivity to dirt, a long service life and of course cost-effectiveness play a very big role. The company relies exclusively on “drylin®” linear plain bearing systems in the adjusting units on the custom-made attachments. As the machine frames in question and their individual superstructures do not always remain in one place at the customer as a rule or are converted on site, the overall weight of the whole unit also plays an important role.

The comparably light plastic material also scored here compared to the steel version. On top of that are its looks. The system profiles are the same in all the folding gluing machines. The aluminum frame and the aluminum rail material on the “drylin®” linear bearings complement each other in form and color. “These are also sales arguments in this day and age,” confirms Max Steiner. “On the one hand, the price of the linear plain bearings convinced us,” according to Steiner, the head of design. “On the other hand it comes down to cleanliness with paper and cardboard handling. Due to the freedom from lubrication, nothing can drip and contaminate the product. That is why all the arguments are in favor of maintenance-free, lightweight plastic components, with which we are able to achieve the necessary weight savings above all. “

Lubricant-free “DryLin®” linear technology

The first contact was made a few years ago at the assembly and handling trade show, “Motek”. “We tested the potential uses for plastic linear bearings and saw they were good,” recalls Max Steiner. “Although our customers are rather traditional, we did convince them about the benefits of the tribo-optimized linear technology. Their machines are running without any problems at all despite the highest working loads in two and three shift operations. ” In the filling level devices, flexible “drylin® W” guide systems are used with a linear spindle or combined as a compact “drylin® SLW" spindle-lift table. Moreover, robust “drylin® T” profile rail guides are proving their strengths. In all cases, the material “iglidur® J” is proving itself. It was designed and developed especially for linear applications together with hard-anodized aluminum surfaces. Further properties are its freedom from maintenance, long service life, low coefficient of friction and its very good wear resistance.

The maintenance-free “drylin® W” linear guide with manual clamp in the lateral adjustment of the filling level device helps to optimize the weight of the packaging machine.

10,000 siliconized paper strips a second

“drylin® W” is also proving itself in a very current project, a silicone paper dispenser. This dispensing system can be used to apply up to 10,000 siliconized paper strips an hour with pinpoint accuracy. The dispensing unit is built into folding box gluing machines among others and used, for example, for the production of cardboard shipping envelopes. The cost saving is considerable. It amounts to up to 70 percent compared to the application of double-sided adhesive tape. “With an available space of 10 mm maximum, a number of axes are fitted with the linear plain bearings. These can be used to achieve the required speeds of 40 m/min, which can be extended to 150 m/min, on very short paths without any problems,” clarifies head of design, Max Steiner.