The Esko XPS Crystal 5080 Delivers Superb Plates

Much has been said about the demands of brand owners: They want bright and vibrant colors. They want just in time delivery of short runs. They want packaging with customization. And how often are the needs of printers heard? Calls for reduced waste, faster makeready, matching the first pull, minimizing downtime and the like are what drive product roadmaps and spawn entirely new solutions.

Technical Innovation Award Esko
Photos courtesy of Esko

But what about the men and women working in the plate department? Far from the picture perfect scenario of pushing a giant, red “MAKE PLATE” button, they too have obstacles faced each and every day:

  • Achieving a more consistent and higher level of quality
  • Reducing waste associated with inconsistently exposed plates
  • The desire to reduce touch points in the plate making process, en route to a future proofed system

Esko heard these problems and went to work developing a solution. The result is the XPS Crystal 5080, a digitally controlled UV LED exposure unit that provides both main and back exposure for photopolymer flexo plates. For this achievement—which one customer likened to a “quantum leap in equipment development”—Esko has won FTA’s 2017 Technical Innovation Award in the Prepress Graphics category.

“Winning always feels great and somewhat humbling! But winning this specific award means so much to Esko,” commented Pascal Thomas, director of flexo business. “The XPS Crystal is the result of a lot of hard teamwork, long hours of research and the dedication of our customers to push Esko to continuously improve digital flexo technology. With FTA’s Technical Innovation Award comes great recognition and probably the best reward our team could have dreamt of.”

How the Technical Innovation Award Winner Makes Plates

The XPS Crystal 5080 works by placing a plate onto its glass surface. The system is preprogrammed with exposure parameters for popular plates. The main and back exposures are done almost simultaneously, using patented UV LED light technology. Nothing else is required from the operator, which is by design, as Esko says the machine fits into a fully automated workflow that can be monitored from a (remote) workstation.

Technical Innovation Award Esko
The optimal relief on a 0.067-in. plate, according to FIRST, is 0.02-in. with a tolerance of ±0.002-in. Light frames typically cannot accomplish this, with a ±0.004-in. tolerance being the norm. With Esko’s XPS Crystal 5080, customers have reported ±0.001-in. floor tolerance. Research has proven that consistent relief leads to consistent dots, which leads to consistent print on press.

The road to the XPS Crystal 5080 began nearly a decade ago, when Esko introduced its inline UV technology. It used UV LED diodes inside the CDI as the means to achieving high consistency while maintaining round top dots—then considered the industry standard. This led to Esko’s Full HD Flexo and brought the company’s UV capabilities to flat top dots.

In customer interviews, Esko says it heard repeatedly that, while it was great to see consistent main exposure, the reverse was true on… the reverse: Back exposure was far from reliable. It was then the need to bring the benefits of UV LED to back exposure was made clear. Another two years of development, system design and plate analysis took place before the XPS Crystal 5080 came to market.

Feedback from those customers who have spent time with the XPS Crystal 5080 say they appreciate not needing to maintain bulbs or tweak exposure times, that the plate floor is “visibly smoother” and dots are “incredibly consistent.”

A Mineral Marvel

Pascal says the removal of the mercury filled fluorescent tube traditionally used in plate making—and the inherent variation that came from things like the tube’s age and quality, its temperature and that of the bed—delivers a more consistent plate. LEDs, in contrast, emit a much more focused spectrum of light and do not require warmup time. It doesn’t hurt that removing the tube is also good for the environment.

Technical Innovation Award EskoAdditionally, the need to keep fluorescent tubes in a heated, “standby” mode can lead to fluctuations during the short back exposure cycle. “Depending upon the state they are in when conducting a back exposure (cold or hot after main exposure), this power build up can be slow (cold state) or quick (after a main exposure) and have an impact on the plate floor,” notes Pascal.

Flexographic Image Reproduction Specifications & Tolerances (FIRST) 5.1 specifies an optimal relief of 0.02-in., with a ±0.002-in. tolerance. With a conventional frame, this presented a challenge; ±0.004-in. is often seen as a more common tolerance. Using the XPS Crystal 5080, Esko customers have reported a tolerance of ±0.001-in.

The amount of time that transpires between the main and back exposures of a plate—also known as dwell time—is a critical component of plate making. A shorter dwell time means finer detail: highlight dots, sharp text and tiny linework. The Esko machine completes both exposures only a few minutes apart, compared to an hour when exposed separately. On top of this, the XPS Crystal 5080’s design means its dwell time is always the same, ensuring consistently repeatable quality.

Going forward, Pascal says the plan is to certify more plates for use with the XPS Crystal 5080; currently all major plates for flexible packaging are available. From there, the machine will become able to expose plates for corrugated printing. And ultimately it will be downscaled to match 4260 and 4835 plate sizes as well.

“The XPS Crystal will bring flexo plate making to the next level of consistency and quality,” he believes. “It will make flexography more predictable and thus, achieve higher quality.”