Based near Southampton, Rotary Logic Systems supplies both stand-alone machines and modules to integrate into all applications in the converting and finishing industries – and every system is bespoke.  Its systems range from those for precision security foiling for anti-counterfeit applications, and specialised in-line, high speed flexographic/gravure printing processes, to machinery for the medical industry. For these, the company uses drives, servo drives and servo motors from Control Techniques.

A typical project was a series of six lines for a manufacturer in India.  Each is a multi-stage anti-counterfeit line for packaging incorporating high precision application of a hot-foil hologram. The lines have web widths of 1320mm, and each comprises unwind and in-feed, foiling, flying head die-cutting, flexographic printing, out-feed and rewind. Here, 30 drives from Control Techniques are on each line – 9kW Unidrive SP drives control the unwind and wind operations, whilst Digitax ST Plus servo drives twinned with Unimotor FM motors control the feeds and all other processes.  A variety of SM-Application modules are employed on many of the drives – including SM-Register, SM-Ethernet, SM-I/O – and the whole line is co-ordinated using Control Techniques’ own high speed network, CT-Net, with the web material drive acting as the ‘Master’.  There are two points of registration – one to the pre-printed material and one to the applied product. A repeatable accuracy of ±0.1mm is required for the foiling process – and this is achieved with a line speed of 80m/minute.

To meet client needs, the company had to devise a system that maintains accuracy of application on an inconsistent substrate.

This was achieved within the software, which compensates for errors for every image, keeping each within tolerance. 

Commenting on the drives, Alan Chandler, director, said: “We particularly like the Digitax ST series of servos, not just because of their flexibility and performance, but because of their compact size.  Equally the compact size of the Unimotors is critical on many lines, including the lines supplied recently to India.”

Control Techniques