A printing solution from Kollmorgen
Flexographic printing technology has become increasingly popular because it more easily maintains printing quality and reduces startup time and waste.
But flexo printing quality depends on maintaining extremely accurate synchronization of the anilox roller and plate cylinder used in each print deck module. Traditionally, this has been accomplished either by gearing the anilox roller and plate cylinder together and driving both with a single AC induction motor or by using separate servomotors to drive each axis through gearboxes. As press speed and printing quality requirements have increased, the inevitable inaccuracies in the gearing system have become a limiting factor on press print quality and speed. Recent advancements make it possible to synchronize the anilox roller and plate cylinder to a much higher level of precision without mechanical transmissions by using closed loop control technology and driving both directly with independent, Direct Drive rotary (DDr). Eliminating the mechanical transmission enables the servo loop gain to be increased, thereby increasing the bandwidth of the servo loop. Speed control and phasing between the anilox and plate cylinder can be closely controlled in the absence of gear backlash, thus providing for higher speeds and inaccuracies for improved print quality. Throughput is also increased because the higher control loop gain enables faster machine operation. This article will examine the trend towards DDr systems in flexo presses and consider alternative implementation methods. Read the full Kollmorgen whitepaper: Direct Drive Technology Improves Flexo Printing Quality and Throughput