Sassenberg, November 2009
The "Association of German Local Newspapers" (VDL) organises informational events for its employees at regular intervals on topics related to timely production. At the technotrans AG headquarters in Sassenberg, the topic was "The correct use of dampening solution".
The title of the event may have sounded a bit too innocuous to reach a wider audience; with six interested people, it was an unusually clear field of participants that arrived together with Claudia Rohnke of VDL. Wrongly, as it quickly turned out since the first presentation by the speaker from technotrans, Hagen Friese, had a slightly edgier title: "The Dampening Solution: Stepchild of process optimisation". Solutions are sometimes so obvious that they are difficult to see even when right in front of you.
"In general, troubleshooting starts with the settings at the machine's control station if the printing process is unstable, too much waste accumulates or deposits are discovered on the blankets," says Friese. "The role the liquids used in this context play is often underestimated." According to the experts, it also does not depend on the perfect composition at its core; much more mundane circumstances can lead to fluctuations in the process. "Many people are familiar with that," the technotrans speaker continues. "If warm water is running in the kitchen and in the washbasin in the bathroom at the same time, then the volume available to the person taking a shower at that moment becomes somewhat low." Described here is the fluctuating pressure from the water pipes, which affects the process of dampening solution preparation with too many simultaneous consumers. "And this is just one of many examples," says Friese.
The topic was water preparation, the addition of additives and the measuring and control technology in the overall process, where a main focus was the efficient filtration and recycling of dampening solution. The summary was, "If you have all these parameters under control in the process of dampening solution preparation, then problems may still arise, but you then also immediately know how they came about." The following were defined as the objective: less workload, less downtime, less waste.
Manfred Stumpe, technotrans service technician, offered revealing practical examples in conclusion to this presentation. He campaigned to always view the dampening solution circuit as a whole. "It makes little sense to define priorities in preparation, filtration or spray dampening systems. Such a process only ever works holistically. And it starts with the fact that the conduit pipes should run empty in the machine circuit when out of service to prevent, for example, bacterial and salt deposits," explains the technician. It was interesting that on the wealth of information, the requests in regards to their own experiences from the group of printing experts in the auditorium increased and became more concrete.
The subsequent presentation by Dr. Peters, Siegwerk Farben, involved a completely different topic, the state of technology in waterless newspaper printing. The expert first described current developments in relation to the consistency and specific characteristics of the colour and the special printing plates required. Due to frequent interjections, however, his presentation quickly focused on a fundamental discussion of the topic of "waterless offset printing". The discussion became divisive against the background of the costs involved for this procedure. "Of course, there are particular requirements, for example, for the press room climate in these solutions," explained Dr. Peters. "However, the fact that a number of newspaper printers have since decided for waterless printing speaks in favour of the procedure. In these cases at least, the cost and benefit certainly stand in an appropriate ratio to each other.' In any case, the discussion following the presentation was also interesting for all those involved.
The event was rounded out by Sven Högemeier of Fujifilm. His topic was "Composition and requirements of the dampening solution". In this presentation, the initial focus was also how important the water quality is as the base material of the dampening solution. Which ingredients are the cause of problems such as lime scale or calcium deposits of rollers was shown decidedly. Specifically, the effect of water hardness and options to control it were clearly shown. For the actual composition of the dampening solution, Högemeier described the individual ingredients and their functions, such as stabilisation of the pH value, quick adjustment of the ink/water balance and protection against algae and bacteria.
The biological component of both disruptive factors just named were impressive by their far-reaching effect apart from the printing process. Bacteria from ingredients of air and water, from paper or dust not only threaten to block the dampening solution circuit. They are the cause of significant unpleasant odours and can be so aggressive that a health hazard to employees working on the machine cannot be excluded. Biocides that have to be replaced regularly are used to combat these microorganisms in the dampening solution additive. "As with most organic substances that work on a biological basis, bacteria also eventually adapt to the biocide used," explains Sven Högemeier. "Sure instincts are needed by the manufacture to find the right time and respectively suitable substitute." At this point in particular, there was a lively exchange with the audience from the practice who reported personal experiences and had concrete questions about optimisation of their processes.
The presentation by Fujifilm was rounded out by a dedicated observation of the dampening solution conductivity. What role does it really play? What relevant information about the overall process can be drawn from it? In the epilogue, it was determined that manipulation of the conductivity does not make sense. Nevertheless, it is an important parameter in the process control.
At the end of the event, the members of the Association of German Local Newspapers (VDL) appeared very satisfied. Information about the dampening solution and the lively exchange about sections of the various presentations brought some new insights for daily work in the print shop. "It was a shame that we were unable to attract more participants for the event," explained Claudia Rohnke of VDL. "Even more so against the background that those who participated were so enthusiastic." The programme included a tour through the production halls of technotrans AG.
