RETROFIT MECCANICI

Model R940: high-evolution electronic retrofit

Developed and installed in 2015

Model R940

Electric-shaft model R940 press with average-to-high performances both in speed and in performance according to the materials to be printed.

In this particular case the press had been designed to print paper up to 120 g/m2, film in the 30 ÷ 160 micron range, bare and annealed aluminium in the 6 ÷ 23 micron range, 50 micron LDPE; in-line lamination, with the secondary material coming also from another press, located on the side, as well; max web width 1800 mm; printing cylinders repeat 460 ÷ 920 mm;  max printing speed 400 m/min.

Practicable on models:

On the electric-axis models of the 900 series, such as model R940, R950, R960.

The case

High-performance press with very particular and specific productions, used intensively, interfaced with another (non-Cerutti) press to receive and process the secondary web, equipped with two different automation platforms:

  • on the main and secondary unwinder and on the rewinder: Eurotherm Drives (today Parker), both for the AC drives (type 620) and the PLC part (Link)
  • on printing units and the remaining parts: Siemens, MasterDrive drives and S7 PLC

The printing units are equipped with vector- and motion-control AC motors; the press is of the electric shaft type (“shaftless”). Eurotherm Drives components are highly obsolete since several years, therefore a fault in one of these components may cause serious availability problems of the spare parts; this is why the Client decided for a retrofitting focused on these parts of the machine.

The intervention, then, has been a partial retrofitting limited to the Eurotherm Drives automation part.

On unwinder 1, unwinder 2 and on the rewinder, the Eurotherm 620 drives for AC motors have been replaced with the new Siemens Sinamics models: on the reel axes, on the infeed and outfeed pulling units, on the drums and on the arms-rotation system, which means 14 drives of different sizes.

The Eurotherm Link PLC CPUs have been replaced with the Siemens S7 S300 series, and all of the Eurotherm Link I/O have been replaced with the Siemens S7 S300 series as well.

After this operation the press is controlled by a “full Siemens” automation platform, which improves management as a whole since all the Eurotherm <–> Siemens communication part (cause of many reliability problems over time, most of all on the Link part) has been removed.

Replacing the electric cabinets was not necessary, and works have been performed on the existing ones and on some parts aboard the press 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; most of all, the rewinder sequences have been enriched thanks to the recent experiences by this very same Client.

Schedule

3-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.

On a 940 press, this retrofitting is just one of the several possible interventions; this one is focused on solving the problems which may arise due to the obsolescence of the Eurotherm Drives materials.

Performance improvements

This press was an example of a quite frequent case of hybrid automation, with different platforms on the unwinders / rewinders than on the printing units, notably to manage the electric shaft, choice that at that time was prompted due to particular technical reasons.

The retrofitting uniforms the platform (in this case, Siemens), with great advantages in data communication between the two structures, which, as a matter of fact, are not separate anymore, but perfectly integrated and uniform.

Notes

This kind of retrofitting offers the best price / performance ratio, since it makes the press 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.