The flexo printing industry is standing at a crossroads where offset printers were a decade ago. Across labels as well as flexible packaging segments, the average run lengths for flexo are getting shorter. The experts are mulling over ways to produce those shorter runs faster, more effectively and still remain profitable. 

While the new presses come with software and hardware developments to improve makeready times and turnaround jobs quicker than ever, the bottleneck also lies in the platemaking stage, which is a complex process consisting of five different hardware devices and six process steps, and lots of manual touch points. 

Shorter print run lengths require flexo plates to be ready faster, within a reliable delivery window, so that printing operations are not jeopardised by press downtime waiting for plates. 

Ganapathy Thillai, application sales manager, flexo sales for South Asia region at Esko, believes, “Therefore, it is pertinent to look at integration of process steps that will drive automation and thereby standardisation, which in turn will result in improving quality, consistency and ease of use, and enable customers to efficiently manage the digital flexo platemaking workflow.”

In that sense, Esko’s Drupa-launched CDI Crystal XPS is a significant development.

The CDI Crystal XPS is a flexo plate imaging system comprising of two parts. One is an updated version of the traditional CDI ablation imaging system. The other is a new plate exposure unit.

On the one hand, Esko has tried to improve ergonomics and user interface with the new CDI Crystal imaging system that consists of an arm that can automatically take a plate and move it from the top of the imager’s glass surface into the imager. When the plate is imaged, it is returned to the glass surface. On the other hand, the new LED UV exposure unit, XPS Crystal, which sits right next to the imager, combines both main and back exposure, supporting all ablative flexo plates. A series of popular plate types from the primary flexo plate vendors like DuPont, MacDermid, Asahi and Flint have already been certified for the Esko Crystal XPS to accommodate most of the flexible packaging print applications. 

Ganapathy says, “The plates are placed onto the glass surface, where very accurate back and main exposures are conducted simultaneously by patented LED UV light technology that, unlike light bulbs, allows very precise control. Nothing else is required from the operator.”
The UV LEDs, which don’t need warm-up time and always emit consistent radiation, are a big advantage over the traditional exposing with fluorescent tubes.  In traditional exposing with fluorescent tubes, one of the uncontrolled variables is the time between front and back exposure. This causes the so-called ‘dwell-effect’ or changes in the floor-shape of the individual dots. 

Ganapathy adds, “As these dots become variable in shape and strength, the print result is negatively affected. The Crystal XPS exposure unit delivers consistent exposure after imaging. This is not possible with fluorescent light sources that are inconsistent throughout a plate, and also degrade over time.”
The Esko HD optics technology deploys high resolution 4000dpi imaging to produce high line flexo screens with smooth gradients to zero, solids, and flesh tones.

Compact footprint
When Noida-based Afflatus Gravures, one of the top gravure cylinder makers in India, decided to venture into flexo platemaking, they opted for Esko CDI Crystal 5080 XPS thereby becoming the first Indian company to invest in the complete line.

The new CDI Crystal 5080 XPS flexo platemaking system is Esko’s answer to the overriding market pressures driven by shorter run lengths and a growing number of SKUs. 
Ganapathy says, “Today, when we talk to flexo pre-press bureaus as well as flexo converters, all they demand is fast plate turnaround to address the increasing demand for product versioning, and the CDI Crystal 5080 XPS delivers that. 

Explaining the step-by-step operation, Ganapathy, says, “The continuous plate production line automatically loads a plate, images a plate, transfers the plate to the exposure unit and provides the correct front and back exposures, while the imager concurrently images the next flexo plate. The parallel imaging and exposures are critical to improved productivity in time-pressured environments. It cuts the number of manual handling steps in half. Making flexo plates finally becomes a coordinated, linear process.”

“The devices can be connected with each other to act as one single plate production line, the CDI Crystal 5080 XPS, thus combining plate imaging and exposing into a single operation.”

The USP is the compact footprint. “This results in 50 per cent fewer manual steps, 30 per cent faster access to plates and 73 per cent less required operator time,” says Ganapathy.

He adds, offset and gravure printing quality has always been the benchmark that flexo has been aspiring to achieve. “With HD Flexo and Full HD Flexo, the gap is bridged. And, with the introduction of the CDI Crystal XPS system, flexo can deliver extraordinary consistency, vibrant colours and increased print quality.”

“I believe, flexo printing can now compete with the offset for quality labels and with gravure printing for flexible packaging. In fact, with more efficient makereadies, it can challenge the upper limits of digital print for labels and folded cartons.”

As a next step, together with its partner Vianord, Esko is further innovating and automating the flexo platemaking process. The next step towards a fully automated flexo platemaking process without manual touchpoints will consist of a bridge between the CDI Crystal 5080 XPS and a plate processing installation. Flexo plates will be imaged, exposed simultaneously from the back and through the mask, and processed in a single streamlined production line, eliminating a few more manual steps out of the process.