By Cassandra Balentine
Part 1 of 2
Wide format sign shops may consider offering labels as an add-one service. Digital label printing enables variability and cost-effective short runs, which are attractive attributes for brand owners looking to test new products or hit new demographics. On the other end of the spectrum, the technology provides startups and small businesses with an affordable option for dressing their products.
Effective finishing is critical to the profitability of digitally printed labels. Two primary finishing considerations for digital label production include cutting and coating. In this two-part web series, we focus first on the former—cutting, specifically popular cutting techniques and configurations—and touch on adaptations for digital printing in part two.
A variety of different cuts are requested for labels, including die, perforated die, butt, and single. Die cutting around the shape of a label, slitting to separate the lanes, and cross cutting are all essential cuts for label production. “Apart from that you might need to make cuts within the label as part of the design. This would either be part of the die-cut plate or the laser template,” offers Donna Covannon, director of marketing, Xeikon North America.
Die and butt cuts are two prominent types of label cuts. With die cutting, labels have a gap or space between each unit, while butt-cut labels are separated by a single cross-direction cut to the liner without a matrix existing between the labels. Juan Kim, CEO, VALLOY Incorporation, explains that butt-cut labels minimize media loss, but there are limited cases for the application. Labels are mostly die cut and kiss cuts leave the backliner to hold the labels as a carriage. Full cuts are applied for sticker pieces or perforation between labels.
Jay Larsen, GM, director of R&D – digital hardware division, INX International Ink Co., says cut types run the gamut from traditional, simple rectangular or circular cuts, to cuts as intricate as lace. “Today’s laser-based cutting systems make it easy to create any cut shape imaginable—without incurring any additional makeready or preparation costs. As finishing machinery improves, customers begin to expect the production of complex cut designs at a low cost to become commonplace,” he states.
Andre Blais, label sales account manager, Heidelberg, points out that rotary cutting is popular for large in-mold labels (IML) and small volumes. One advantage of rotary cutting—depending on the label shape—eventually material can be saved, which is an interlocked layout of labels.
High die punching—or cut to stack—is an essential cutting element of label production. “The technology used depends on the method of printing, production volume, and label size and shapes,” shares Blais. He explains that high-volume labels are primarily finished with cut-to-stack solutions. High-volume IMLs are also produced this way.
“A majority of labels produced on narrow web machines are pressure sensitive and finished with inline rotary die-cutting devices. This process cuts the shape of the label through the top sheet, leaving only the liner intact for label application equipment,” adds Blais.
Many label presses, including flexographic, hybrid, and digital systems incorporate finishing/cutting inline. However, near line and offline configurations are also utilized.
Covannon says there are two important elements that decide whether the cutting should be performed inline or offline—irrespective of the process. The first is speed of the individual units, for example inline finishing may reduce the full line’s speed to that of the slowest device. The second is job length and turnaround times. Smaller jobs often require more flexibility on the converting side.
Victor Gomez, director, industrial labels, Epson, believes the decision to go in, near, or offline depends on the business model and the profile of the company. “The answer of offline versus online is straightforward at the extremes, comments Gomez. Inline is great for web to print, offline is for shops that outsource the finished stages. “The majority of converters don’t operate in the extremes. Ideally, the throughput of the component pieces of inline equipment will be roughly equivalent. If there is a mismatch, one device is beholden to the speed of the other. Offline will tend to maximize the throughput of each process. The more processes you string together inline, the longer it takes to recover from errors,” he points out.
“Die-cutting inline is almost always done when printing on a flexographic press due to run lengths,” admits Blais. “When die-cutting inline on a digital or hybrid press, the changeover time is longer because of the die setup. An analysis of work mix, equipment investments, and labor required to run multiple machines should be done to determine the lowest cost method.”
For short-run, low-cost products, Larsen notes that finishing inline versus offline can make the difference between profit and loss on a job, or even being able to get the job in the first place. He points out that digital printers with inline laser die cutting enable the cut to be part of the artwork and pass directly through from artwork to the laser with no setup.“One of the unique capabilities of some laser-based cutting systems is that every cut can be unique. When customers learn of this possibility, creative minds begin to think of new marketing possibilities and even completely new business.”
Die cutting inline also reduces the overall time to produce the finished label, with less labor and waste. Blais says cutting inline takes place primarily on web printed labels. However, the speed of the printing process has to eventually be reduced in an inline configuration. “Collating and making proper stacks of the labels is challenging and very labor intensive,” he adds.
Inline configurations are good for businesses built around quick turnaround—when you want as few processing steps as possible. “It is great for similar, repetitive, consistent jobs,” suggests Gomez. If you are covering multiple sectors with varied sizes and media types, you will most likely require versatility.
Larsen believes there are few challenges associated with a well-integrated inline production system. “If the digital printing system is directly coupled to the laser or traditional die cutter, all the registration can be handled electronically with no trigger mark required,” he says. Though minor, gaining the extra few millimeters of printing width can sometimes enable the printer to accept a job or change a step-up to save time and materials. “The direct coupling allows registration to be set without optics, sensors, or adjustment of a sensor to read a mark.”
Larsen adds that a traditional rotary die cutter can also be put inline in the same printer that contains the laser die cutter. This combination gives the best of both worlds. “Repetitive production of a traditional label shape can use the rotary die cutter and run at full speed while other jobs can use the laser for full flexibility and no makeready times.”
Inline cutting may lead to a finishing bottleneck, as the machine will only print as fast as it finishes. “Laser die-cutting speed is determined by many factors, including materials type and thickness, laser power, focus, and mirror speed. When selecting the laser system, consider what specifications are needed to meet the speed requirements of the rest of the solution. The other thing to consider with inline laser cutting is that certain materials may not be able to be cut with a laser, resulting in the need for an additional inline or offline rotatory die cutter,” notes Larsen.
Depending on the label size, layout of the sheets or web, Blais says it is almost impossible to achieve a similar speed as with the printing device. Label size also has a major impact.
“Organizationally and depending on the type of label, a specific converting line will be used regardless of the printing technology, meaning it will always staff offline,” comments Covannon. Label converters are asking for more end-to-end solutions. “We can see the increasing volumes for digital label production lead to a dedicated production line for a certain application. In which case, the finishing will be inline.”
Kim says cutting offline enables the operator to adjust the tension more precisely and allow for better and more stable finishing including lamination, UV coating, die cutting, foil stamping, matrix removal, slitting, and separation. “If cutting speed varies in synch of printing speed, load in tension can be influenced and slitting can be irregular between steps.”
Label applications require some form of cutting before they’re ready for action. Depending on the final application, a variety of equipment and configurations are available to support label converting. If a wide format sign shop is considering label printing it is important to recognize the need for some type of finishing component.
Mar2020, Digital Output