Faster, better, cheaper

5 June 2006



Today’s wide web presses have to match demands put on converters by the packaging end users, writes Greg Ginnow, a leader on the mechanical engineering team at Paper Converting Machine Company (PCMC)


In today’s packaging market converters are being required to produce products with quicker lead times, better eye catching colours and designs at a reduced cost. In other words: faster, better, and cheaper. These same demands are being pushed down from the printer to the equipment manufacturer. PCMC, as well as other suppliers to the flexo industry has responded with advanced technologies and services.

The trend in recent years has been for the wide web industry to print at faster and faster speeds. The gearless presses of today are running packaging substrates consistently at speeds of 600m/min. Even faster, gearless CI presses printing tissue and non wovens are pushing speeds of 900m/min. In both of these examples, the machine design plays an important role in the success of transporting the web through the machine. Also, without the continuing development of drive systems and servo technology, web handling at high speeds while maintaining print quality would be impossible.

Web handling is not the only requirement for running at high speeds. Winder performance has become a speed limitation on the modern press. To alleviate this winders have been designed to transfer at maximum speed. Automated roll handling is also being used to help keep the press running at maximum process speeds.

Another significant factor is the development of enhanced dryer systems. Both inter colour dryers and the tunnel dryer have been designed to achieve higher operating speeds. The patented PCMC Extreme dryer system uses a compressed dryer nozzle to gain a significantly higher heat transfer coefficient than conventional gas fired dryers. Consequently, the system uses about the same amount of space as a conventional dryer, while achieving higher operating speeds.

But higher speeds are just a small part of the answer for today’s printer. A better measure of press productivity is to measure effective m/min. This calculates the average speed during the whole job, including change-over and makeready.

Automatic wash-up and sleeve handling systems can reduce complete change-over times to half an hour on the widest (2.2m) gearless presses. In addition, automatic press controls are reducing makeready times by using statistical analysis, high resolution feedback, and vision systems. The combination of these control systems reduces set-up time and ensures good material comes off the press faster than from previous machines.

Resulting from the demand for higher quality the 10 colour gearless press has been adopted as the standard product offering. To meet industry needs, the range of width configurations for gearless presses has also increased. Today, gearless CI presses can be purchased from 1-2.2m in print width. A key component to meeting the width requirements of the industry while improving the register performance is the advance in drive technology. Frameless motors, which extend the motor rotor to include the load, are now being used within the press. By eliminating any type of gearing or coupling between the motor and the load, the drive system can be tuned to be more responsive and the potential for wear eliminated. The net result is a system that can deliver a dot more accurately for registration and match the speed of the web for a better quality of dot. Print quality is further enhanced by the use of 150 lpi plate screens and 1,200 – 1,400 lpi anilox sleeves.

Another trend has been towards six or seven colour process work. More and more converters are seeing the advantages of extended process colours. However, there is a learning curve to applying this technology, just as there is on printing at high speeds if you haven’t done it before. To assist customers and co-suppliers in the industry adapt to new technologies, PCMC has opened a technology centre where print trials can be run to experiment with different ink sets and other process variables, or to hold training without disturbing production at home. A 1.2m gearless CI 10 colour Infiniti press, a 450mm wide in-line eight colour Evolution press, and a dedicated 450mm wide two colour CI Evolution press within a lab line configured for non woven converting operations are housed in the centre.

Reducing costs

A challenging trend for converters has been the erosion of margins. Material costs have been sky rocketing. Energy costs continue to climb. At the same time, the packaging customer won’t keep inventory, asks for shorter run lengths, and demands lower prices. Machinery manufacturers continue to look for ways to give relief to the converter. PCMC is helping by evaluating the total energy used to run a new wide web press. Examples of energy saving systems as standard equipment include AC motors with regenerative drives and the Extreme drying system. In fact, one customer’s energy audit demonstrated a 72 per cent saving over a conventional press of equal size.

Waste reduction is another area of opportunity. Besides improved quality, one of the other benefits of increasing automation is the consistency it brings to the operation. By incorporating automatic press controls to set print and register and also monitor and adjust settings over time, the product off the press becomes more consistent, which in turn reduces waste during makeready and during the job.



Contact

PCMC
Tel: +1 920 494 5601





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Infiniti features in PCMC's technology centre Infiniti features in PCMC's technology centre


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