RETROFIT MECCANICI
Model R135: high-evolution electronic retrofit
Developed in 2014 and installed in 2015
Model R135
Model R135 press for publishing, standard composition for catalogues and magazines printing, average performance (installed and upgraded later).
In this particular case the press had been designed to print paper up to 100g/m2; max web width 1900 mm; up to 6 ribbons; printing cylinders repeat 830 ÷ 1530 mm; max printing speed 54.000 copies / hour.
Practicable on models:
All of the publishing presses produced from the 90s onwards, many of which are still equipped with Cerutti analogical controls and first-generation PLCs, up to the latest models equipped with obsolescent Siemens automation systems and MasterDrive drives.
The case
Hybrid-automation press: Reliance (drives and PLC on the unwinder and the angle bars / folder units) / Siemens (main motor and printing units).
The press had, and still has, a mechanical transmission, while speed-controlled DC motors have been replaced with new AC motors.
Summing up: all of the DC drives have been replaced with new AC ones, and the whole, obsolete PLC part (Siemens S5, Reliance) has been replaced as well.
The retrofitting proceeded on several directions – notably:
- DC motors replacement with new AC ones
- main motor repositioning in-line with the main gear, removing the belt transmission
- installation of an independent motor on the folder, disconnecting it from the main gear
- replacement of the obsolescent hi-tech electric parts
The unwinder’s DC motors have been replaced with AC ones (belts drive, axial motors, infeed pulling unit); new Rockwell Powerflex 700 drives, a new Rockwell ControlLogix PLC CPU and new Rockwell 1756 and 1734 PLC I/O have been installed. In replacing the DC motors with AC ones, it has been necessary to replace the electric cabinet as well, since it is not possible to modify the existing one.
The press’ main motor (DC) has been replaced with an AC one, which has been installed in-line with the main gear, thus removing the belt transmission; in this case, the new Rockwell Powerflex 700S has been used, and the whole electric cabinet has been replaced as well.
On the remaining part of the printing units control, the whole PLC part has been replaced, with the installation of the new Rockwell ControlLogix CPU and of the new Rockwell 1756 and 1734 PLC I/O, modifying the existing electric cabinets without replacing them.
The motors of the pulling units in the angle bars / folder area have been replaced as well, switching to AC motors on the main, secondary, auxiliary and folder pulling units, managed via the new Rockwell Powerflex700S drives and the new Rockwell 1756 and 1734 PLC I/O; here too it has been necessary to replace the electric cabinet. The old Reliance Automax PLC CPU controlling this part, including the folder’s sequences, and located in the V1 cabinet, has been replaced with the new Rockwell ControlLogix, modifying the existing cabinet.
The folder has been made independent from the main gear with the installation of an AC motor powerful enough to put it in motion in sync with the press, as in the last-generation publishing presses, with all of the relevant advantages.
A new electric cabinet, with a Rockwell Powerflex 700S drive, has been supplied for the folder’s motor drive.
Finally, all of the interfaces towards the parts that had been connected to the press, recovered from another Cerutti press that had been decommissioned due to a fire, have been implemented on the new, complete Rockwell automation platform; all of the relevant sequences have been reviewed and made compatible with the new general configuration.
The CPS has been replaced to make it consistent with the rest of the automation; furthermore, the CMS has been supplied, for remote connection and assistance.
Schedule
5-weeks downtime plus two weeks of assistance during production. The press underwent a complete general test and inspection, as well as the main print tests with the chosen productions.
Targets
The main goal of the retrofitting was to extend the plant’s technological life and to prevent long downtimes in the event of faults in components not available anymore on the market, notably in the electrical part.
Furthermore the opportunity was seized to replace the DC motors with AC ones, with much better performance most of all in the more sophisticated controls such as the control of the angle bars / folder pulling units and of the folder’s independent drive, and with the huge advantage of not requiring specific maintenance operations.
Performance improvements
Switching to the independent drive on the folder gives great advantages, both logistic (since a mechanical transmission between the last printing unit and the folder’s clutch is not necessary anymore) and technical (in managing the collect / non collect productions and the folder’s timing in respect to the printing units).
Usually, some hybrid controls / functions (such as humidifiers preset, temperature controls and so forth) may be completely integrated as well.
Notes
Retrofitting on publishing presses for catalogues and magazines is possible also on presses equipped with other automation platforms (Siemens), including hybrid platforms (Siemens / Reliance, Cerutti / Siemens) without further technical difficulties.
