Unlocking the potential of high-quality printing on tissue material
How BST eltromat web guiding and web monitoring systems combine with SDF machines to ensure top quality in the production of tissue and non-woven items
Web guiding and web monitoring systems by BST eltromat for managing and monitoring production quality are among the most important quality assurance components found in SDF machines. These systems allow SDF customers all over the world to produce high-quality printed items using tissue and non-woven materials.
“Print quality standards for paper napkins are constantly on the rise all over the world,” says Peter Allard, Managing Director of Schnitt Druck Falz Spezialmaschinen GmbH (SDF), which is based in Monheim am Rhein, Germany. “And thanks to the ongoing increase in wealth in newly industrializing countries, new markets keep on emerging for our machines.” SDF’s market sector is incredibly dynamic and competitive, Allard explains.
“Our business has always been in machines that our customers can use to print napkins and other tissue items such as tablecloths – with a very high level of quality. We have worked in close partnership with BST eltromat ever since our company was founded in March 1997,” Allard continues, reflecting on a collaboration that has lasted for 20 years. “Their solutions for web guiding and web monitoring give our customers all the options they need to reliably manage and monitor their production quality.”
Ever since its foundation, SDF has always exclusively used BST eltromat systems for web guiding systems and web monitoring in its machines. “Our supplier’s broad portfolio allows us to focus on what is the best solution for our customers – both technologically and financially – on any given machine, without limits,” says Allard. This suits his company very well, especially when dealing with customers who are cautious when it comes to investments.
A little more class is welcome today
Although paper napkins were once generally seen as simple consumer goods, the passage of time has seen them grow to become lifestyle items whose quality and appearance could not be more important. “Prestige items might not be quite the right term, but especially when people are entertaining guests privately, they would now much rather spend one or two euros more if it means that their napkins match the design of their tablecloths and flatware, or even if they just add a touch of class or ambience,” says Allard on this trend. Beautiful napkins always bring something to the table. The patterns also change to match the time of year or celebrate special holidays, such as Easter and Christmas. In short, paper napkins have long since become a seasonal business that gives manufacturers plenty of room for creativity.
“This is quite an extreme example,” says the CEO, handing us a stack of napkins with city maps printed on them. It is amazing how clearly you can read the street names, even though they are printed on absorbent material and are not much more than eight-point font. “Here we have a set of African-themed napkins, all with the same reds and ochers in the design,” Allard continues, pointing to a picture frame on the wall of the conference room. Grazing zebras, a family of cheetahs, an African man at sunset with a spear in his hand, and seven other designs as well – the paper napkins in this frame are also notable for their fascinating quality. This is when we notice the other frames on the walls of the room, all of which contain dozens of other high-quality napkins of all kinds.
Register printing requires expertise
There can be no doubt about it: This is an industry that is consistently maximizing the potential provided by modern technology in order to produce top-quality napkins and other tissue products. What resolutions can be used when printing on the soft, tensile webs? “Our machines can now print in a 34 screen with up to nine colors,” Allard replies, “though the material qualities and grammage get progressively poorer.” This is because the extreme competition has forced manufacturers to save wherever they can on tissue products. “It requires a certain level of expertise to register print on these materials,” says the CEO, summing up the issue.
But this, he explains, is exactly what his company specializes in, and the challenge that they work on hand in hand with BST eltromat. “When faced with new or highly specialized challenges, we get the experts from BST eltromat involved in the project planning for the machines at an early stage to help us find the best solutions possible.” For example, the companies are currently collaborating to help one or two customers integrate a 100% inspection into their systems for finding printing errors. “Since the width of the material web for tissue products is the same as the width of the end product, we can’t work with register marks at the edges. This prevents the option of register mark control, which is used in offset printing, for example. For cost reasons, most of our customers wouldn’t accept us cutting a strip off the edge of the product,” says Allard. After all, a tonne of tissue material costs around 1,200 euros these days, Allard reminds us.
Web guiding systems play a key role
Web guiding systems keep the material webs on a straight path as they travel through the machines, thus fulfilling an important requirement for perfect printing and embossing quality. Such a system is necessary because the rolled-up tissue materials become misaligned when they are fed into the machine. In other words, their running is unbalanced. “Since the print rollers in the flexographic printing units are always the same width as the material webs that run through the machines, if running is unbalanced during printing, it makes wavy lines with white edges. The web guiding systems prevent this from happening by constantly monitoring the material feed and ensuring perfectly balanced running as the webs run through the machine,” says Allard.
As such, SDF generally integrates two web edge guiding systems into its printing machines: a CompactGuide web guiding system before the printer and a rotating frame guide designed especially for SDF before the embosser. However, on simpler machines that have no printing units, a web guiding system is simply installed before the folding units.
In the future, SDF will generally be using CompactGuide web guiding systems in a variety of widths to match its different machines. For the machine manufacturer, one of the key features of this system is its high level of user friendliness, as it can be operated via the control unit. For machines that process tissue materials such as paper napkins, the system is equipped with two optical IR2011 web edge sensors with infrared lights. These sensors reliably detect the edges of the web, even when subjected to heavy soiling.
These also make up a traditional web centerline guiding system that compensates for any changes in web width. This is particularly important for tissue and non-woven materials since the tension or other factors can cause deformation – shrinking or squashing, either parallel or perpendicular to the direction of travel – in the material webs for these applications. In these cases, the web centerline guiding system prevents wavy lines from being printed on the sides of the materials.
Reducing waste to a minimum
When it comes to web monitoring, SDF relies on BST eltromat’s POWERScope web monitoring systems. These are installed in the machines after the last print unit. The new POWERScope 5000 in particular is the perfect match for “what our customers expect from this kind of system,” says Allard. It is easy to set up and very simple to use. This is particularly effective in improving production reliability when the machines are operated by well-trained staff. User friendliness is also an important feature for customers in newly industrialized countries.
“The POWERScope 5000 helps our customers to minimize waste and ensure consistently high print quality,” is how Allard summarizes the key responsibilities of the web monitoring system. The camera transmits images synchronized with the running web to a monitor for the machine operators. On SDF units, this monitor is always integrated into the swivel panel on the central machine control system. With the intuitive multi-touch function available on the latest generation of POWERScope systems, it is easy to move the camera to the required position. The machine operators can store these positions in the system so the camera can be moved back to them at any time during the print job. And thanks to the gesture control feature, they can zoom in right up close to the printed web by spreading two fingers apart on the screen, as known from smartphones. This allows them to see details that would be invisible to the naked eye and check the printed dots or the register marks, which may be “hidden” in the print patterns.
During setup, the operators let their machines start up slowly and use the images supplied by the POWERScope 5000 to bring the colors in to the register. This takes just a few moments, but reduces start-up waste to an absolute minimum. On top of this, the POWERScope 5000 systems also continuously monitor the print quality during production. Customers who are prepared to invest in a second camera system can also use the POWERScope 5000 to monitor the embossing of the print.
In addition to the web guiding and web monitoring systems, SDF can also include other BST solutions in its machines for customers with special requirements. For example, turn bars and folding triangle adjustment systems are sometimes added to the standard machines SDF offers, while some customers have also requested a built-in SUPER HANDYScan 4000 so that their printing presets can be adjusted semi-automatically.
BST eltromat technology is the industry standard
More than 120 SDF machines are in use across the globe, the majority of which are in production 24 hours a day, seven days a week. All of these machines are equipped with BST eltromat web guiding systems. Around 80 of them have printing units – and these machines also contain BST eltromat web monitoring systems. “BST eltromat has established itself as the industry standard. Many of our customers include this manufacturer’s solutions in the specifications required for their machines,” Allard says. This is often purely down to the reputation for reliability that these systems enjoy on the global market. At the time of writing, no BST eltromat system has ever experienced a failure in an SDF machine.
In the high-quality tissue product manufacturing sector, customers usually run their machines at speeds of up to 250 meters per minute. Technically speaking, they could actually run even faster, but keeping the speed down stops the print rollers from gathering dust, so the machines do not need to be cleaned as often. This increases the number of packs of napkins a customer can produce in one day, even despite the reduced speed. It also enables them to continuously improve their quality.
“Generally speaking, our customers produce up to 11,000 packs per shift, each of which contains 20 napkins. These will then be sold in supermarkets, garden centers and other shops for up to around five euros per pack,” says Allard. “Our customers used to tell us that their investments in our machines had paid for themselves within just one year.” However, Allard explains, the extremely competitive nature of the sector makes it unlikely that this is still true. “After all, manufacturers of paper napkins and other tissue items need effective distribution, good contacts in the market and, of course, buyers who can have them running our machines at high capacity.” And that’s to say nothing of the prices for which these items can be sold to the public.
Digital printing is the future
“Time after time, we have driven this industry forward with our innovations,” Allard explains. The example he uses is the first napkin printing machine with servo drives, which SDF launched in 1997/1998. Today, the CEO sees his company as a pioneer in the field of digital printing. This approach has seen SDF work with OCE/Canon to develop a digital napkin printing machine designed especially for tissue materials. This inkjet process enables the user to print and customize even small batches of high-quality napkins. SDF is OCE/Canon’s worldwide exclusive partner for this printing solution.
“More and more companies are ordering custom-printed tissue products for their events. And with private customers it’s the same: 50th birthdays or other family celebrations. This is an area with huge potential,” says Allard excitedly. There are already online shops that allow customers to order napkins with a high level of customization, he notes. SDF’s customers use fully automated processes to send the orders straight to their digital printing machines. “In our sector, as in many others, digital printing is the future,” says Allard. Fortunately, SDF and BST eltromat enjoy a partnership that will remain almost completely unchanged despite this technological revolution.
Schnitt Druck Falz Spezialmaschinen GmbH (SDF) is based in Monheim am Rhein, Germany, and currently has around 30 employees. The company was founded in March 1997 by engineer Peter Allard and machine-building expert Andreas Rother. So that it can focus entirely on its expertise in the development and production of machines for the tissue and non-woven fabrics processing industry, the company buys in all its parts from external providers. Once each machine is designed, SDF contacts selected suppliers all over Germany to order the components it needs. The machines are then assembled and set up for customer acceptance at SDF’s Monheim plant, before being dismantled into their constituent modules and shipped out. Around 120 SDF machines are now in use, primarily in Europe, Asia and the US.