Linoprint, a product division within Heidelberger Druckmaschinen AG, uses the latest valve developments from SMC, the world leading experts in pneumatics.
Customers from the food and pharmaceutical packaging sector make the most exacting demands on the quality and speed of printing systems right down to the last dot. This last dot can, for example, play a decisive role in the traceability of medicines. In the food division manufacturers are faced with tough tasks, on the one hand as the result of strict guidelines for batch identification and, on the other, as the result of seasonal product changes which cannot be resolved with the one uniform sticker or with the currently widely used low resolution printers.
Therefore with Linoprint, Heidelberger Druckmaschinen AG, the leading World manufacturer of sheet offset printing machines uses digital drop-on-demand technology (DoD) with Piezo inkjets. In their printing heads, ink droplets are “shot” from a pump chamber onto the surface to be printed with the help of the piezo electrical effect. The droplets create the individual printing dots which are immediately dried using a downstream UV drying unit to ensure quick continued processing. The Linoprint product range DriveLine B thereby achieves printing speeds of up to 25 metres per minute and recognised resolutions of up to 1,080 dpi (dots per inch).
In close cooperation with its customer and based on this principle, Linoprint is developing flexible drop-on-demand printing systems, the labelling for easy black and white signs through to decorative multicolour printing using high resolutions. The Linoprint systems are outstanding in that they can be integrated into a standalone solution as well as into an existing packaging system. Moreover, even in the event of small lot sizes as from one piece Linoprint delivers economic processing compared to conventional printing processes.
More than just putting ink on paper
The printing of various materials ranging from paper to cardboard, blister packaging for tablets, aluminium or plastic films, through to labels in conjunction with high printing speeds presents specific challenges for the inks used. Each surface has it own special peculiarities. The inks used in the systems are therefore adjusted in accordance with respective customer requirements and the surface types. Their chemical composition must guarantee quick drying after UV radiation as well as a perfect print image. At the same time, it must be ensured that drying does not occur in the nozzles, lines, tanks or valves. This presents an additional challenge both for the system design as well as for all other components which come into contact with the ink e.g. solenoid valves which are required for controlling the inks and the cleaning agents in the device. Such fluids, which are often aggressive, can have a direct effect on the service life of components and, in the worst case scenario, even damage them and bring the entire printing process to a standstill.
“The compatibility of the materials used in the valves with the inks used in the printing system” is, according to the unanimous opinion expressed by the design team involved, the most important criterion when looking for suitable valves. After all, only the resistance of the components guarantees the reliability that Linoprint feels duty bound to offer its customers.
Striking gold with SMC
Moreover, the Linoprint system developers also highlight the fundamental importance with regard to purchased parts of high functional safety and the easy assembly of all components. In the area of solenoid valves the Development Department has struck gold with SMC. The Linoprint designers describe SMC as their “main contact partner for valve technology” and stress the value of seamless, continuous customer care by suppliers.
According to Holger Bellmann, “Meeting the material requirements of Linoprint was our prime concern when selecting valves”. As an SMC engineer working in the field, Holger has offered Linoprint´s developers long standing technical support. “During cooperation with Linoprint on this project it soon became clear that the best solution for the switching of special inks was the tested combination of case material and sealing. The required flow output, as well as the available installation space, was best suited to our VX2 valve series”
The VX2 series features direct operated 2-port solenoid valves, that SMC offers in a variety of port sizes and material combinations. Various electrical connections, voltages and threads provide the finishing touches to the diversity of this series.
New components with low energy consumption make their entry into the system development
Whilst the first tests are ongoing in Linoprint´s test centre using selected material combinations for the solenoid valves, SMC is working in its R&D Centre in the Japanese city of Tsukuba on the development of energetically optimised solenoid valves. With the new coils in the VXE range, which can be obtained for 12V and 24V DC voltage, the electrical power consumption drops to less than one third compared to conventional solenoid coils. According to Holger Bellmann, “It was immediately obvious to me that these coils would be very interesting for Linoprint´s application. Moreover, as the VXE2 are compatible with the VX2 valves used in the test, the coils can even be exchanged at a later date.”
“In addition to the valve’s excellent resistance and operational reliability, one of the performance options that particularly appealed to Linoprint was our energy-saving option”, he continued.
The coils in the SMC VXE range are fitted with a built-in energy saving circuit which, after a switch-on time of 200 milliseconds, limits the power consumption to approximately one third of conventional values. The valves can therefore make a contribution to reducing the Total Cost of Ownership.
There is another advantage to be gained from the lower power consumption which must not be overlooked. These solenoid valve coils generate significantly less heat than all comparable valve coils on the market. This is an additional benefit, which prevents the risk of excessive heating in the control unit in printing systems and, therefore, resulting negative effects, such as undesired ink drying within the system. This represents a further contribution to the extraordinary reliability of the entire process.
For the future Linoprint would expect to see the following from SMC: “Unwavering commitment and cooperation in solving problematic issues in the area of valve technology.” As part of this mission, thoughts are already being turned towards new components such as hose plug connectors with comparable resistance features.
SMC VXE solenoid valves for different gases and fluids are available in three designs:
• VXE2: direct operation for port sizes between 2 and 10mm,
• VXED2: pilot for port sizes between 10 and 50mm and
• VXEZ2: positively controlled for port sizes between 10 and 25mm
The power consumption of 12V or 24V DC voltage coils is between 1.5 and 3W depending on the body size. There are different case materials available (brass/bronze or stainless steel) and sealing
materials (NBR, FKM, EPDM, PTFE).
Linoprint is specialised in the development, sale and servicing of digital drop-on-demand printing systems based on piezo electric inkjet technology. These systems are outstanding by virtue of their high flexibility and a vast application spectrum.
SMC Pneumatik GmbH based in Egelsbach near Frankfurt is a wholly owned German subsidiary of the SMC Corporation. The company is the worldwide leading manufacturer of pneumatic components for industrial automation. Additionally, it develops manufacturers and sells an increasing range of automation components including solenoid and process valves, electrical drives, ionizers, air dryers...etc.