RETROFIT MECCANICI
Model R940: high-evolution electronic retrofit
Developed in 2016 and installed in 2017
Model R940
Top press of the 900 series with average-to-high performances both in automation and in performance according to the materials to be printed.
This model is particulartly suitable to print paper up to 100 g/m2, film in the 15 ÷ 25 micron range, laminated materials up to 120 g/m2; on-register lacquers and cold seal application; max web width 1250 mm; printing cylinders repeat 450 ÷ 1020 mm; max printing speed 400 m/min.
Practicable on models:
On the following mechanical-axis models of the 900 series: model R910, R920, R930, R940, R945, R950, R960.
The case
High-performance press with very particular and specific productions, used intensively, with Reliance Maxitron M9000 digital drives and Reliance Automax PLC. Equipped with DC motors, the press had, and still has, a mechanical transmission.
Today (2018), and from several years already, many hi-tech electric components such as the drives and the PLC are highly obsolete, therefore a fault in one of these components may cause serious downtime problems and an increase in repair times due to the difficult availability of spare parts.
For these reasons the Reliance Maxitron drives for DC motors have been replaced with the new, digitally-controlled Rockwell PowerFlexDC models: on the main motor, on PU9’s independent drive, on the unwinder’s and rewinder’s reel axes, and on the Corona, the infeed and the outfeed pulling units, which means 9 drives of different sizes. The Reliance Automax CPUs have been replaced with the new Rockwell ControlLogix, and all of the Reliance I/O, European series, not available on the market anymore have been replaced with the new Rockwell 1756 and 1734 series.
Replacing the electric cabinets was not necessary, and works have been performed on the exisiting ones directly on site to reduce the installation time (and, as a consequence, the downtime). The materials to be replaced have been accurately prepared and pre-wired at Cerutti HQ to reduce installation time.
All of the press sequences have been reviewed and improved; all of the parts damaged over time and of the defective sensors have been replaced; then a complete general test and inspection has been executed.
The management system has been replaced as well to match the new automation platform and the hardware and software state of the art, and implementing the possibility of connecting the press to the “24/7 by Cerutti” remote-assistance service.
In this particular case, some mechanical improvements have been implemented as well, such as a structure modification on the dancing rollers of the infeed and outfeed pulling unit (thus improving their dynamic features and, as a consequence, their adjustability), the addition of rollers on idle cells in the infeed and outfeed areas to monitor web tension, the supply of new-type cooling rollers without inner tank.
Schedule
4-weeks downtime plus one week of assistance during production. The press underwent a complete general test and inspection, as well as the main print tests with the relevant materials.
Targets
The main goal was to solve the obsolescence of the electronic components; this is why the Client decided for a retrofitting focused on the electric / electronic side of the machine.
Furthermore the opportunity was seized to replace some transducers with other ones, of higher performance and updated to the state of the art, such as the thermal probes for temperatures survey, the electropneumatic transducers and several sensors.
Performance improvements
All of the most important sequences have been re-built, improved and enriched.
Notably, the mechanical modifications on dancing and cooling rollers allowed a great improvement in the adjustment of the web tension, in particular at the inlet and between printing units, thus getting a better printing quality with a more stable printing register most of all during speed variations.
The management system too has been improved in its handling of several functions, such as the preset of operational units, tensions, positions of the compensating rollers, temperatures, acceleration slopes, taper on the rewinder, possibility of activation of a continuous (24/7/365) remote-assistance service.
Notes
All 940 models can be retrofitted as here described.
Furthermore, this kind of retrofitting offers the best price / performance ratio, since it makes the press, even with its features of mechanical transmission with DC motors, perfectly aligned with the current state of the art in automation. These factors have a positive effect on the return on investment of such a retrofitting, taking into account also the further 10-15 years increase in the obsolescence term of the spare electronic components.
