LASER-ENGRAVED SLEEVES OFFER QUALITY CONTROL ADVANTAGES
Just as explorers came to North America hundreds of years ago and discovered a new continent, unparalleled advances in digital engraving and elastomer sleeve-making have arrived in the New World. With these advances, a case for a 100 percent in-the-round (ITR) elastomer workflow can now be made. Driven by unprecedented efficiency, consistency, quality, and speed, identified and acted upon years earlier in Europe; a new age of expansion and innovation in the world of flexography has begun.
WHY ROUND VS. FLAT: PRESSROOM PRODUCTIVITY
- No plate mounting stations
- Less material and labor
- Perfect registration
- Quicker makeready
- “Up to color” quicker—considerable labor,
substrate, and ink savings
- Easier to repeat jobs
- Longevity and durability on long runs
- Fewer variables = fewer problems
- Increased press speeds
WHY ELASTOMER VS. POLYMER
- Durability = savings
- Quality control in imaging and manufacturing
- Supply chain and re-use
- Production speed—from manufacturing, to
imaging, to printing
EFFICIENCY DRIVES DEMAND
Flat plates have traditionally dominated the North American flexography market. Even in the last several years, the limited amount of cantilevered presses, the long lead time for sleeves, and the perceived high cost have limited adoption. But printers are now demanding ITR technology for several reasons. The most immediate—efficiency.
ITR sleeves require no plate mounting stations, mounting material or labor. This allows for quicker makeready. When mounted, digitally engraved sleeves are aligned to each other during engraving (using notches) for perfect registration. This leads to considerable savings on labor, substrates, and ink when getting up to color.
With fewer variables and a more uniform printing surface, press speeds can be increased beyond what is capable with flat plates. Short run and repeat jobs can be changed out quickly, and the increased durability of elastomer sleeves allow for longer printruns. Since there are fewer things that can go wrong with sleeves during the printing process, like undetected
flat plate mounting issues, plate lift, cylinder bounce, lack of uniformity, etc.; ITR can help eliminate variables that lead to problems during printruns that cause press down time.
While individual elastomer sleeves may be more expensive than plates, because of their increased productivity, combined with the elimination of redundant plates, elastomer sleeves will actually lead to an overall cost savings over flat plates.
Quality improvements with sleeves over plates are the second reason that printers are switching to ITR. Digitally engraved elastomer sleeves have unparalleled registration. Because registration and uniformity problems with flat plates are amplified across the web. Flat plates often have a significant amount of waste.
For instance, a printer worked with eight lanes of fine detail graphics printing on a 66-in. web, and was consistently forced to throw away 33 percent of the printed material because of registration issues. Switching the plant to elastomer engraved sleeves allowed the production team to consistently hold a .003 trap across the entire sheet, reducing waste to zero. Photopolymer flat plates have a traditional tolerance of +/- .015 tolerance across a 66-in. web.
“The tolerance spec of elastomer sleeves is +/-.001,” boasts Carey CEO Gary Moravcik. Printers are also able to combine sleeves with flat plates to gain some of the advantages of the sleeve without having to eliminate flat plates altogether.
One of the reasons for the slow adoption of ITR in North America, as compared to Europe, has been the fewer cantilevered presses in existence here. The last few years have seen a marked increase in the installation of cantilevered presses. However, many printers have struggled to realize immediate returns on their investment.
Print speed increases are easier to attain when using a 100 percent sleeve based workflow. Sleeves allow faster printruns and allow more printruns on multi-million dollar flagship presses like W&H, PCMC, and F&K. One print salesman recently remarked, “Running a brand new press with flat plates is like buying a Ferrari and driving it only through school zones.”
Sleeves also embrace new technologies like extended gamut and Opaltone™. The uniformity, consistency, and registration of sleeves combined with the ink transference, density, and resolution of digitally engraved elastomers allow faster printing speeds with superior quality. This allows printers to leverage new technologies to achieve ROI now, instead of later.
ELASTOMER’S INHERENT ADVANTAGE
Cost, perceived supply chain problems, and limited inventories have held back the use of elastomer sleeves in America. However, new advances in imaging and manufacturing are bringing the inherent advantages of elastomers to the attention of printers.
Elastomer sleeves are thicker and more durable and can print two-to-four times longer than polymer sleeves. This eliminates the need to buy multiple plates or polymer sleeves for long runs and repeated abusive short runs that require many cleanings and press cylinder mountings. This leads to cost saving in the long run, and cost predictability.
A typical comment from printers who have switched from polymer to elastomer sleeves is, “Elastomer usually costs less than polymer, and we’re only buying one set instead of two. So, the savings are great, and our print results are more consistent.” Elastomer sleeves eliminate the need to purchase expensive cushion adapters and replace them in the future, further saving costs.
Sleeve durability does not just come from elastomer’s increased ability to stand up to press pressures, corrosive inks and cleaning solutions, but also from the way they are imaged. Digital control of the halftone shoulders contributes to dot stability and reduces breakoff. Which adds durability and
consistency. Below surface engraving also produces a more consistent product by reducing highlight press gain. Even if a job is slightly over squeezed from pressto- press and operator-to-operator.
We’ve been told by many print customers, “Our pressmen love sleeves.” They love elastomer sleeves even more because below surface engraving reduces the risk of printing shoulders and inconsistent dot gains. Control of the shoulders allow for razor sharp text. Even at one and two point, and the ability to print smaller reverse text without filling in.
Elastomer customization is possible through the chemical and physical processes of sleeve manufacturing itself. “It is now possible to create a special elastomer compound specifically for your press to get the absolute best from your fingerprint,” says Moravcik. “Because elastomers have no
photographic layer, which is the time consuming part of new polymer development, customized materials for your specific needs can be developed in weeks and not years.” He continues, “Slight changes in elastomeric compounds can increase ink transfer for specific inks and substrates where polymers have hit a dead end.”
A wide variety of elastomer materials with different durometers and ink lay down characteristics are now available. Printers can achieve higher press speeds and maintain print contrast with higher ink densities. At a test run with a set of custom laser-engraved elastomer sleeves, a customer was
amazed at the unprecedented printing event, “The density was so high we had to cut it… That’s a good thing!”
Quality control is another area where elastomer sleeve manufacturing and imaging have grown leaps and bounds. Kodak has developed a system (Flexcel Direct) whereby all sleeves are quickly pre-scanned on the engraver to check for a flawless surface and rejected before imaging if any imperfections are detected.
Laser-engraved sleeves also have an inherent quality control advantage over photopolymer. Laser-engraved sleeves have three steps to imaging: file prep, engraving, and rinsing. This means that the sleeve only has to be mounted one time, engraved, rinsed, and shipped. Photopolymer sleeves
have many more steps: file prep, mask ablation, exposure, development, wash-out, and several options for drying, post exposure, etc., and then shipment. This adds several more variables to the imaging process, each of which adds more analog steps and points of failure in the imaging process.
“By increasing the market volume and bringing in multiple suppliers from around the world, we have created a competitive atmosphere in the USA manufacturing infrastructure: increasing the quality, reducing the supply time, and reducing the raw material unit cost of elastomer sleeves,” says Moravcik. New covering methods which allow even higher quality
sleeves, with no joins and no overlapping are in development.
Another supply chain innovation has led directly to cost savings with elastomers: the ability to regrind and reimage sleeves. “Elastomer sleeves can be produced with wall thicknesses from .125-in. to .500-in. with phenomenal print results on all,” claims Carey salesman and flexo technology expert, Ed Stolzman. Elastomer sleeves can be kiss ground to the
next lower repeat and re-imaged once the sleeve is done being used, creating as many as three-to-four uses of the same sleeve. When considering overall ROI, this will drastically reduce costs.
ENCODED ELASTOMER SLEEVES
Flat plates can’t talk, but elastomer sleeves can! Carey Color is spearheading a revolutionary innovation for sleeve manufacturers, which allows them to uniquely encode each sleeve and track that sleeve throughout its
lifetiime. Carey’s encoded elastomer sleeves can tell you where they’ve been and what they’ve done from manufacture to regrind, to the last impression.
Senior Developer Chad Gray remarks, “Print managers can scan a sleeve in their warehouse with a mobile device and determine its size, when it was made, elastomer composition, how many times it’s been on press,
etc. It’s now possible to track the entire lifecycle of an elastomer sleeve!
“By linking this information to our secure, yet globally accessible customer database, production managers can get a new job from sales, and instantly be able to see how many sleeves are in the pipeline that will fit
that job or what could be reground for that job.” Gray says proudly, “This idea was conceived and developed at Carey Color as a direct response to our customers’ needs. Printers need a way to manage their inventory
and know where and what every sleeve in their enterprise is at a moments’ notice. We are giving them that.”
BELOW SURFACE IMAGING
Because of their increased ink transfer and contrast capabilities, the fastest running, highest ink density materials for press speeds of 1500 to 3000 fpm are direct engraved elastomer sleeves. To best leverage elastomer ITR technologies, Carey Color was chosen to partner with Kodak to be the first
North American install for the Flexcel Direct System.
Flexcel’s TIFF Front End takes below surface engraving to unprecedented levels. Shoulder angles, undercuts, variable relief depths, and other below surface imaging can all be controlled through the conversion of a traditional 2-D 1-bit TIFF to a 3D TIFF. The 3D system has been combined with the extremely precise laser diode array imager that is faster and
more powerful than any of the high resolution modulated C02 or fiber lasers on the market. This gives the quality advantages of engraving digitally while approaching the speed of the LAMS process.
It also features redundant diodes, autofocus optics, and cantilevered sleeve loading. This all leads to faster prep, imaging, and handling times and has afforded dramatic reductions in actual engraving time, thus dramatically reducing overall costs of imaged sleeves to customers.
“What’s the most exciting part of all of this?” asks Moravcik with a smile, “Even though it blows the doors off everything out there, this architecture is still in its infancy stage, with nowhere to go but even faster, with even better quality.” Welcome to the new world!