Thanks to the new variable block thickness VPN-Flex PUR nozzle from Robatech, the Vareo perfect binder from Muller Martini is capable of displaying its strengths in book-of-one production even better than before – and boosting its performance by 20 percent, as our first user of this technology, CEWE in Eschbach (Germany), experienced.
Since PUR is increasingly being used for runs of one copy and the Vareo is the optimal solution for book-on-demand jobs, the Muller Martini three-clamp perfect binder is supplied with the newly developed optional VPN flexi-nozzle. That nozzle system was developed in close cooperation with Robatech.
The previously used nozzle system – which was developed for the needs of conventional production – already boasted advantages, including highly precise and even glue application. Production in runs of one copy, however, also requires dynamic book thickness adjustment and corresponding compensation of the glue volume – that is the innovative nature of the new system.
Always Sufficient Glue Available for the Next Gluing Process
A servo motor quickly and accurately adjusts the required application width of the slotted nozzle. The PUR glue, which is always fresh, is not displaced during the adjustment process and remains in the special nozzle chamber. Thanks to the construction, the glue cannot leak during adjustment of the application width and it is always ensured that sufficient glue is available for the next gluing process. There is no need for cleaning at all in the nozzle slot area.
The new PUR nozzle system with proven melt-on-demand technology and a circulation system with flow and return retains all the advantages of the previous system, namely volumetric dosing, circulation for glue conveying, control via the machine display, and the two-kilogram cartridge. The nozzle comes into its own for the production of books in runs of one copy with constantly varying block thicknesses, irrespective of whether the adjustment is from thin to thick or from thick to thin.
Enhanced Precision of the Start/stop Functions
The new control system has further enhanced the evenness of glue application and the precision of the start/stop functions. The high adjustment speed of the application width – make-ready for 10 mm width adjustment in less than a second – considerably increases the performance and quality (continuous uniform glue application with cross-checking by the LAK glue application monitoring system) of the Vareo, especially for book-of-one production
“Thanks to the new PUR nozzle, our productivity is 20 percent higher,” newly confirmed me Gerd Wild (see picture above), Division Manager at CEWE in Eschbach, where over a million photo books are produced annually. “That’s especially important for us, since we specialize in runs of one copy and are reliant on high-performance systems, especially in the pre-Christmas peak season; we feed pre-selected products to the Vareo according to size, but not according to the thickness of the book spine.”
Following successful field tests with ongoing production of real CEWE photo books, the renowned German photo book company is the first mass user of the new PUR nozzle. Gerd Wild explains: “We worked together extremely well with the Muller Martini and Robatech technicians.”
Less Daily Cleaning Work
The fully re-designed application head is also a major advantage, says Gerd Wild: “Daily cleaning work – we always clean if a shift is not followed immediately by another – now takes just a quarter of the time that it did before.” If necessary, the application part with the glue chamber can be disassembled, cleaned, and reassembled much easier, and that makes it faster.
Vareo users that have previously only produced using hotmelt, can retrofit the new variable block thickness PUR nozzle with little effort following a feasibility check. It is also planned for the Muller Martini Alegro perfect binder.