Expert Srl flexo printing machines are the result of a shared experience: The knowhow of the Veneto manufacturer built up over decades is completed with the specific experience of Bosch Rexroth in designing automation solutions conceived for the printing industry.
The company Expert Srl of San Martino B.A. (Verona) has for many years had to its credit a full range of solutions that cover the different needs of flexographic printing: from central drum machines, intended for productions that require quality and high speeds, to the evolved stack machines, more versatile and easily adaptable to specific needs (for example in printing on both sides of the material and in pre-printing).
It is to be emphasized that Expert’s entire output uses gearless technology.
«The completeness of our offer – said company rep. ingegner Leone Nardon – is essential to meet the diverse needs of today's printing market. Bosch Rexroth, that has supplied us with various technological lines – like the platform for electronic automation, linear technology and pneumatics – has accompanied us in designing optimized solutions based to suit our specific production needs».
The consolidated experience in the flexographic print sector, combined with the versatility in the development of technological solutions made with the support of specialists in the Bosch Rexroth printing sector, make Expert a company capable of proposing a broad range of cost-effective solutions, that can satisfy the most varied demands of the current flexo print market.
For printing and prepress – Expert responds to the most stringent demands in terms of accuracy and print speed with the range of the central drum machines, starting from the Ideal and Dynamic models, up to the new Active, which will be exhibited in May at Drupa, the most important international fair covering the sector.
But Expert’s attention is also concentrated on pre-press, where the stack machines (with independent cylinders, Ed) have an excellent purchase investment/performance ratio: «There is a broad and varied market sector – Renato Giovannini and Alejandro Signorelli, Expert sales managers state – featuring print formats 1500 mm to 2000 mm wide and beyond, where the central drum machine is costly and less flexible if compared with the versatility of the stack solution».
«The stack machine – Giovannini states – as well as enabling printing front and back in a single pass without the use of diagonals, is perfectly suited to tubular materials, even in direct line with the extruder, also ensuring the required accuracy on various thicknesses of substrate. In the printing of plastic bags – the manager goes on – we have even guaranteed the performance for the parts where the thickness, due to the inner fold of the bags, reaches 4 times the nominal gauge of the thin film, confirming the great versatility of the stack machines».
«The independent cylinder solution – adds Signorelli – can be flexibly adapted to different types of materials such as paper, cardboard, flexible film, used in diverse fields: from food packaging, packaging of FMCG and industrial goods, to printing on wallpaper».
Gearless – The stack machine is available, in its gearless version, with independent drive of the clichè, anilox and counter-pressure cylinders: a drive using brushless IndraDyn S series servomotors, managed in synchronism with the Synax for Printing control platform. All the machine axes, including servo motors for driving the unwinders-winders or required calendars, are run using the standard modular IndraDrive series, which together with greater energy efficiency in the management of DC electrical power of the shared bus, also enables a significant reduction of internal bulk and electrical panels thanks to the 20 and 36 amp biaxial modules.
«The electric shaft synchronization of the print axes – said Nardon – has enabled a degree of accuracy to be reached comparable to that of the central drum machine, especially during transient acceleration and deceleration and with materials with good inextensibility characteristics.
In addition to increasing productivity, the gearless machine is extremely flexible, adapting to different material thicknesses, whose wide range of variation (0.1 to 0.8 mm) is not limited by the mechanical coupling of the gears»
Expert has also relied on Rexroth for developing the automation of the pneumatic system, using high accuracy solutions such as the electronic pressure control and pre-assembled battery valves, which enable space saving on board machine as well as reducing wiring and assembly operations performed by the builder.
The linear motion of the color units, realized through carriages moved on with ball bearing guides and 5% precharged screw transmission in precision class ISO5, is entirely supplied by Rexroth.
The stack machine reaches printing speeds of 350 m/min, and is configurable both in the mechanical and in the gearless version with a variable number of from 4 to 6, up to 8 color units. The inking can be by closed doctor blade chamber or by rubberised cylinder, the replacement of the cliché and anilox sleeves is done directly in the machine.
Expert completes its range with the unwinding/winding units, developed both as part of its printing lines, as well as specifically designed: «At customer request- Nardon explains – we draw up the complete mechanical design and the relative automation of shaftless unwinders for rolls of diameters up to 1650 mm, a width of 2500 mm».
Control cabinet equipped with Bosch Rexroth driver.