On Feb. 25-26, Bobst Bielefeld, Germany, held an open house with its focus on high-speed and wide-web-width flexo printing.
Following the approach taken at Bobst’s highly successful open house last October, the event was divided into a seminar session in the morning and a print demonstration in the afternoon. Visitors from fifteen countries around the world attended the event and got an update on the latest flexo printing and process related developments.
The print demonstration utilized the flagship of the F&K 20SIX series of CI flexo presses, a “CS” model featuring a print width of 65 inches, a repeat of 47.2 inches, and a speed of 1,970 feet per minute.The extensive range of equipment onboard the press included smartGPS, shaftless winders, a BOBST three-chip camera, a 100 percent inspection system, a special slitting device, and an auxiliary system for sleeve and cylinder handling.
During the demonstration, two five-color jobs were run at 600 meters per minute, i.e. the maximum mechanical speed of the model showcased. The changeover of the print sleeves in between the two jobs was performed using the cylinder handling system, which gave visitors an idea of its fast and user-friendly handling of even large format printing hardware. For impression and register set-up, smartGPS, Bobst’s unique off-press technology was used, so visitors witnessed a complete changeover - from the end of the first five-color job to saleable quality of the subsequent job - in less than 15 minutes.
During the seminar session, Bill Duckham and Hermann Koch, Bobst Bielefeld sales directors, spoke about specific challenges on a press designed for high speed and wide width applications, and about technical solutions integrated into the F&K 20SIX to meet these challenges. Visitors heard that, most importantly, the specific technologies and measures that ensure consistently superior print quality throughout the process are related to: - mechanical rigidity of cylinders and bearings; high precision impression adjustment; ink transfer from the ink chamber to the substrate; and to guaranteed drying of ink on the substrate. Michael Schmidt from Siegwerk Druckfarben highlighted the topic of high speed printing from the perspective of an ink manufacturer, presenting practical examples, limitations, and potential for optimization.
The second part of the seminar session was dedicated to plastic film as a packaging substrate. In his speech about the latest developments in extrusion, Sascha Skora, from Reifenhäuser Blown Film, presented typical problems converters are faced with - from pellet quality to reel/winding quality of the film material. Skora also updated the visitors on the latest quality inspection systems for ensuring superior film quality throughout the extrusion process. Last but not least, Dr. Carolin Struller, from Bobst Manchester, illustrated the company’s in-depth research on AlOx clear coating, from the way it is produced and its performance on various filmic substrates, through to its barrier retention with subsequent processes of printing and converting. AlOx coating is especially suitable for packaging where product visibility is required, including baked goods and microwaveable food.
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