The gravure printing and lamination Open House held at Bobst Italia in S. Giorgio Monferrato from October 15-17, rounded up in style the showcase of web-fed printing and converting technologies displayed by Bobst during three open houses held for the first time in close succession in the UK, Germany and Italy.

Lamination was the first technology on show, starting with the Bobst SL 1000 duplex laminator dedicated to solventless applications. The job run on the machine showed coating of 20 μ metallized BOPP film laminated to 20 μ BOPP which had been pre-printed on a Bobst F&K flexo press.  

The 150 visitors watched the production data unfold on a screen which showed the rewound material length and the machine speed increasing from the 50 m/min starting speed to the production speed of 400 m/min. 

A flexible production line providing the possibility of line customization in terms of web width, shafted or shaftless winders and reel diameter, the SL 1000 also provides for a range of configurations, and the machine in demonstration featured the lamination nip after the machine bridge just before the rewinder.

As the Bobst flexo trolley is acknowledged especially for the performance in coating solvent-based adhesives directly on thin aluminium foil, the demonstration showed the efficiency and output quality with a job coating solvent-based adhesive on 6.35 μ aluminium foil which was then laminated to a 12 μ PET film. The Bobst flexo system provides the possibility of a better coating of the adhesive on thin aluminium and an excellent optical quality of the final product.    

The CL 850D laminator achieved a production speed of 430 m/min, producing a high quality, duplex laminated structure without any defects.

Then gravure printing technology came under the spotlight, starting with the Bobst Rotomec 4003HS high speed press which presented a number of innovations.

The Bobst Rotomec 4003 platform of gravure printing presses is very successful as it provides different solutions, each addressing specific printing requirements and applications.

The Rotomec 4003HS gravure press on show featured a new configuration with shaftless cylinders.  The demonstration showed printing of a 6-color food-packaging type job on 12 μ PET film, printing repeat 625 mm.

The sequence was completed automatically in less than 5 minutes, generating approx 100 m waste. The press then reached top production speed of 500 m/min. Visitors could follow all the stages of Taps setting and accuracy of the register system during the acceleration ramps and during production on a screen placed on the machine catwalk.

After the printing demonstration Bobst presented the new trolley solutions called Twin Trolley.  A new concept in terms of trolley design and machine make-ready at changeovers, it allows the offline separation between the printing cylinder and the color, which enables movement of both or either of them to storage or to a different printing unit, thus enabling to keep the CMYK process colours always on the machine independently from where in the press they should be positioned.

Other important features, all aimed at decreasing consumption and increasing the speed of job changeovers are the possibility to use 50 litres commercial ink tanks on board the trolley, a 3-way valve and a pre-washing cylinder device.

The advantages are manifold: the 50 l commercial ink tank has a suitable capacity for high-speed processing of long run production, and it does away with the need to transfer the ink to a dedicated tank, thus no cleaning.  The 3-way valve enables a separate discharge of the dirty solvent during pre-washing. The pre-washing cylinder device enables easy cleaning of the printing cylinder on board the machine.

The efficiency of the new Twin Trolley system enables it to achieve up to 50% reduction of ink and solvent waste as well as considerable time savings. 

The second gravure printing machine in demonstration addressed different market needs by printing a six-color cosmetic sachet-type job on a 20 μ BOPP substrate on a Rotomec MW 80 press. The MW (Minimized Waste) press is dedicated to printing medium web, very short run production.

The demonstrations provided the open house visitors with a comprehensive overview of the industry.


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