The potential of laser die-cutting and digital finishing | Labels & Labeling

Laser die-cutting of self-adhesive labels is not new. The first machines showing the technology at Labelexpo exhibitions can be traced back to the mid-1990s, although in the early days it was more of a novelty rather than a practical solution for the high-speed cutting of complex shapes. These early models were not only cutting the label to shape, but laser etching and also cutting windows out of the release liner. They certainly attracted a lot of interest, but were seen as rather slow and expensive at that time, as well as prone to causing brown edges to the die-cut face material, and not always waste stripping effectively.

However, the concept of being able to change the shape of labels on demand and not have to purchase expensive tooling for each shape or size of label – and often delaying the converting line – has long excited the label converter, and now, the folding carton producer. it reduces set-up time and waste through instant make-ready, and it takes away the need to lift and store heavy magnetic cylinders and dies in the workplace. Because there are no tools, there are no costs for tooling, or production delays while tools are manufactured and supplied.

Looked at on that basis, digital color printing of labels on demand makes the subsequent use of digital laser cutting on demand for labels sound even more attractive. Indeed, there are now quite a number of label converters worldwide that are already using laser cutting technology for a wide variety of label converting applications. Digital finishing with laser technology is additionally now finding application in folding carton production. So how does laser cutting work?

LASER CUTTING

Laser cutting technology works by using computers to direct the beam of a high-powered laser at self-adhesive, in-mold, carton board, or other substrate materials that need to be cut and vaporizing the material that is in the beam’s path, so leaving an edge with a high quality surface finish.

The way in which the beam path is directed towards the substrate, and the powering on and off of the beam, will both affect the specific cut pattern that the origination artwork requires.

Laser cutting software that comes with the technology today effectively handles most operations behind the scenes, from web control, registration, laser powering, slitting, etc., which makes the operator’s job comparatively simple and the machine straightforward to operate. The software does all the difficult jobs automatically behind the scenes.

One advantage of laser cutting over mechanical cutting is that there is no physical contact, and therefore no cutting edge which can become contaminated or damaged – either by the material or during the cutting process. There is also no wear on the laser, which provides for consistent cutting precision.

Because of the small diameter of the cutting beam in the latest systems, materials that were once unsuitable for laser cutting can now be cut.

Both high-end and lower cost laser cutting technologies are available. The lower-cost systems are made from less expensive components, yet probably have superior capabilities to even the most expensive machines of just a few years ago. The high-end, state-of-the-art systems today have the ability to consistently cut far more intricate designs, in a wider range of substrates and tighter tolerances than ever before.

Certainly since the early days digital laser finishing has changed significantly. Laser die-cutting technology for labels today – and now even for folding cartons – is undoubtedly far superior to that of 16-17 years ago. It’s faster, more efficient, has a higher cut quality and, if used for the right kinds of applications and markets can certainly both reduce a converter’s costs and create value-added opportunities.

Yet laser cutting and automated digital finishing has still tended to be somewhat slow to gain mass adoption in label converting plants – perhaps because of its early perceptions – and is still only in the very early days of adoption in the folding carton sector.

LASER DIE-CUTTING WORKSHOPS

It was to address the perceived issues and better highlight what laser cutting technology can offer converters that Labelexpo introduced its Laser Die-cutting Technology Workshops at the 2012 show held at the Donald E Stephens Convention and Conference Center, Rosemont, Chicago in September of that year.

Developed over a period of six months or so in the run up to the show, the challenge was to bring a number of laser cutter manufacturers together to set-up and run the same cutter profiles on the same substrates, from the same files and MIS, so that label converters could compare and assess the resulting samples from each machine. Indeed, see just what modern laser cutter technology can achieve, what materials can be converted, how pre-printed reels can be re-registered, what kind of complex shapes can be cut, and how this impacts on cutter speed. Certainly the likes of this exercise had never been attempted before.

The laser cutter participants and machines in the Workshop sessions came from: Spartanics with their L1000 Finecut High Speed Laser, with a working width of 350 mm; from ABG International with the Sabre Extreme Twin laser and a working width of 340 mm; from Delta Industrial Services with its Delta Edge Laser Technology and a web width of 330 mm; and from SEI Spa with its Spa Label Master, again with a web width of 330 mm.

The aim of these Workshop sessions was fourfold:

The range of jobs run during the workshops included prime product labels on polypropylene face material with a PET liner, industrial labels on metalized film, blank labels on a white label stock and paper liner, as well as freestyle labels of their own choice. Not only were there different jobs, but the label shape and size changed during the run of each job.

Origination for all the set label designs and die-cut files was provided by Esko using their Esko Suite 12. For the prime labels a CERM MIS system supplied information from estimate to order via JDF to Esko and Xeikon – who pre-printed the prime labels on a Xeikon 330 with in-line D-Coat – and also provided a software file to each cutter manufacturer to drive cutting and cutting changes.

Three versions of the industrial label design

(Figure 8.1) were again handled with Esko Suite 12 in association with EFI Radius and with EFI Jetrion, who pre-printed the labels. Step-and-repeat of the designs on the web was done by EFI, including the creation of eye-marks for cut-to-print registration for the laser cutting machines, information to indicate changes of logo and cutter during the run, as well as laser sequential numbering.

The blank label designs were also prepared in Esko Suite 12, including eye-marks for cut-to-sheet registration. CERM Business Management and Automation systems supplied by MIS workflow, with information from estimate to order sent via JDF to the Esko Suite 12 workflow software.

It was also interesting to see some of the more intricate shapes of labels that were produced by the participants for their freestyle label designs – shapes that would be difficult, expensive or perhaps impossible to produce using conventional die-cutting technology.

An example of what can be produced with laser technology were the labels run by Delta Industrial.

As can be seen in Figure 8.2 there are complex cut-outs in the middle of the label (the white areas) and also a wave formation along the top of the label.

So what were the conclusions from these Workshops? In essence, that purchasers of laser cutting systems in the future can certainly be assured that there is now a far greater pool of knowledge and information amongst the key industry suppliers that will be of benefit to the industry in the years ahead. But what were printers/converters learning from the Workshops? Undoubtedly quite a lot if the message from the demonstrations, presentations and discussions during the show were anything to go by.

KEY BENEFITS OF LASER CUTTING SYSTEMS

In summary, the main understandings and key benefits of laser cutting technology that were demonstrated at the Workshops were:

Put together, laser cutting can play a valuable part in a modern label converting plant, working with conventional and digital printing outputs to offer materials and cost efficiencies, reduce waste, provide added-value opportunities, sequential coding and numbering, and more complex shapes and lengths. The technology has a valuable role to play in the future and more label converters should be evaluating the benefits and opportunities when drawing up their investment plans.

So what is available and how does the printer/converter make a decision on investment?

LASER CUTTING TECHNOLOGIES AND THEIR SPECIFICATIONS

There are a number of companies now providing laser die-cutting machines that can be linked to roll-label presses or used as stand-alone devices.

Key players that participated in the Laser Die-cutting Workshops at Labelexpo 2012 are shown first below, with brief descriptions of their machines and their specifications, followed by other leading laser cutter machine companies.

ABG INTERNATIONAL SABRE EXTREME

The Sabre Extreme Laser Die from ABG International is an individual module that can be integrated into the company’s Omega converting line, digital label finishing line or any other rotary web-fed machine. It comes with Digital Die Shop software which enables the importing, creation or editing of die patterns.

Machines use ABG’s Digiflow and Digilase software which identifies and loads job parameters automatically. The machine is capable of reporting live production activity to an MIS system every 30 seconds through JMF files.

All jobs for the machine can be prepared off-line and either downloaded through an Ethernet cable or via a removable storage device. It has a ready-to-use operating system which uses Windows-based software. This enables new files to be loaded and then changed over on the fly, even while the existing job is still running. All fumes are extracted and filtered.

In addition to self-adhesive labels and products, the machine can also handle folding carton materials and cut through substrates to remove holes, slots, etc. Machine specifications for the Sabre Extreme Laser Die are as follows:

AB Graphic International offer the widest range of digital finishing equipment currently available and have been involved with digital print conversion for more than 18 years.

DELTA INDUSTRIAL SERVICES DELTA SPECTRUM II

The Delta Spectrum II with Edge Laser Cutter manufacturing solution features a human machine interface and touchscreen interactive graphics.

Process settings can be saved as recipes and easily retrieved per application. The standard design includes six unwind/rewinds. Working width is 330 mm.

Machine specifications for the Delta Edge Laser are:

Main end-use applications for the Edge Laser Cutter include pharmaceutical labels, medical devices, industrial/consumer finished products and packaging. Every machine is custom built.

SEI SPA LABEL MASTER

The SEI Spa Label Master is a highly professional digital finishing modular converting system for roll materials in labeling and packaging that can be configured as a single laser die-cutting station or can be completed with optional finishing and controlling units.

The finishing line provides a great combination between speed and accuracy, flexibility and customization, modularity and expandability and is the result of 30 years of experience in the laser field.

Machine specifications for the Spa Label Master are:

Work that can be produced on the Label Master includes die-cutting, micro-piercing, engraving, coding, and options for flexo printing, hot stamping, inspection and slitting.

SPARTANICS L-SERIES

The Spartanics L-Series Laser Cutting Machines use sophisticated quality and depth control software to undertake the complexities of laser cutting and are designed to handle polyester, polypropylene, polycarbonate, paper and many other substrates. The machines use a sealed CO laser with a 210 micron spot size that shows no burn through marks or discolorations. Spartanics Optimization software imports the die-cutting file into the equipment software. Set-up time is no more than 5 minutes for new jobs; zero set-up time if a barcode reading job changeover feature is used.

The company has been in business for over 50 years and is a recognized leader in laser cutting.

Machine specifications for the Spartanics L-Series Laser Cutting Machines are:

The Spartanics L-Series cutting and converting systems come in 210 mm and 350 mm web widths, while the Spartanics L-500 machines with a Dual Laser Head are designed to laser cut rolls or sheets of material for the label, packaging, carton board and abrasive industries. Machines can be customised for specific applications.

ALS ENGINEERING LASER DIELESS LABEL CUTTER

The ALS modular laser cutting system enables customers to customise their laser cutting system exactly to their specific needs, or upgraded at any time as and when the customer requirements change. The basic machine consists of an unwinder, laser die-cutting unit and a rewinder with matrix removal.

Cutting speed, depending on spot diameter and wattage, operates from 1.8 m/sec up to 5.6 m/sec.

Optional equipment includes a laminating unit, varnishing unit with UC dryer, slitter unit, sheet feeding equipment, shingle conveyor and a stacking unit.

CARTES L360 LASER DIE-CUTTER

Cartes was one of the first to industrialize laser technology in the label industry and has more than 200 machines installed worldwide. Machines can be supplied in a power range from 250 to 350 watt, with a semi-sealed single or double laser source.

The company’s CO laser is claimed the only semi-sealed source on the market, offering reliable, everlasting cutting power. The Laser 360 Dual is an extremely productive version equipped with a double laser source that achieves a speed up to 80 m/min in terms of web speed. A Laser 250 model is also available. Machine specifications for the Laser 360 Dual are:

The L360 can convert paper, cardboard, film, foam, sandpaper, plastic materials for pharmaceutical and automotive applications.

DPR LASER CUTTER

DPR has Introduced a new laser die-cutter. Working in both roll-to-roll and sheet mode, the unit is designed to cut a wide range of substrates including coated paper, PP and PET. Fine control of laser power makes it possible to obtain half/full cutting, marking, braille, progressive numbering and barcodes.

GRAFISK MASKINFABRIK L330

The GM L330 Laser Die-Cutting fully modular system from Grafisk Maskinfabrik offers a fully digital mirror system for superior laser cut quality. No tooling is required as files are downloaded from Pre-Press and provide zero change-over time. Quick changeover is assisted by an optional bar code reader and integration into Esko graphics pre-press solutions.

Machine specifications for the GM L330 are:

In addition to the digital finishing of self-adhesive labels the GM L330 can also provide laser finishing of IML labels and carton board.

A 400W drop-in laser-die-cutting system for GM’s popular series of DC330 converting line is also available. The laser system is compatible with Esko’s PLT/HPGL file format and features a substrate database. The laser system can be fitted with a barcode reader for automatic job change and a serial number writing software package.

SELECTION OF A LASER CUTTING SYSTEM FOR LABELS

As can be seen, there are undoubtedly an array of high-end and more cost-affordable laser cutting machines available for the label converter to choose from. The challenge for the converter looking to invest in laser cutting, however, is to ensure that they source a machine that is best matched to their label requirements and to avoid models of laser cutters which have obsolete software or other out-of-date design features.

Certainly, both software and hardware technology have changed significantly since the launch of the early laser cutting systems, in particular to make the latest equipment more user-friendly, to enable it to operate faster and to provide enhanced cutting accuracy.

The converter also needs to avoid the extra costs (up to 20% more for higher-end components) that are not required for most label cutting applications. Cost-effective systems can still produce high quality outputs providing the software engineering and system integration are expertly done.

When looking to invest in laser cutting there are a number of areas that the label converter needs to understand. These are shown in Figure 8.9 and explained in the following paragraphs.

The cutter image

Laser die-cutters are able to take any vector-based digital image – perhaps generated on an Esko system and import this into the cutter’s operating software so as to generate the job set-up within a few minutes. Hence the term digital die-cutting. Digital label printers with digital laser cutting can therefore move from the artwork stage to a finished printed and die-cut label within a very short period of time.

Job changeover from one image to another has also been addressed and is faster with the latest laser cutting technology since the next job can now be downloaded while the current job is still running. Larger die-cut patterns can be loaded plus static pattern cutting for testing small lots of material samples. The images can be easily stepped across the web, the material cut type and cut path selected, with the cutter then ready to go.

Some laser cutting systems today have manual and prompt pattern changes with the ability to store millions of patterns and can also be networked to an art department or the Internet with newly created cutting patterns being immediately available to the operator.

Depending on the supplier, software may be incorporated in the equipment so that the operator can import or create the die line pattern, edit the die line pattern, and then test the die line on a virtual machine before going to actual production of the finished product.

Cutting performance

The laser cutting systems used for die-cutting labels will generally have a highly controlled laser with a spot size of smaller than 210 microns, together with laser control software that enables labels to be cut without overheating. If heat is not controlled the adhesive layer may melt and cause the release liner and labels to stick together rather than coming apart when required at the point of application.

Certainly, any laser cutting system that makes automatic label application difficult is not worth the bother or investment. Poorly controlled laser cutters are not suitable for any label application involving pressure-sensitive adhesives and release liners.

High quality laser cutting systems should not exhibit any signs of burn-through marks and should provide a crisp narrow cut without any sign of the scalloped edge that was often found with older laser cutting technology. The best results are achieved using sealed laser tubes.

Cutting speed

Laser cutting machines today are now considerably faster than the earlier models on the market and, rather than just being used for prototyping, are now used for die-cutting labels at full production speeds. They can rapidly make the minor adjustments needed to move the laser beam around the label design. The higher the wattage of the laser, the faster the cutting speed in most label cutting applications. Cutters of up to 400 watts that were prohibitively expensive 5 or 6 six years ago are now far more competitive in price.

However, the most important consideration in laser die-cutting is not the actual linear cutting speed. It is the actual speed that the web moves through the machine, which is governed by the complexity of the artwork and the ability of the software to optimize cutting. Undoubtedly, the best laser cutters are able to automatically optimize the cutting sequence through the software to produce the maximum web speed.

Cutting speeds will depend on a number of variables, including material thickness, the amount of cutting required, the amount of small radius curves, the complexity of the cutting shapes, the number of labels across the web, and the amount of jumping between features. An example of maximum web cutting speeds, based on information provided by ABG International, is shown in the table above:

Substrates to be converted

While there are always some limitations in conventional mechanical die-cutting because of the need for actual physical contact with the substrate, laser cutting has the capability of cutting many materials that may be difficult or impossible with mechanical cutting, such as for very thin substrates, abrasive substrates, and in the cutting of adhesives.

Even PVC and polycarbonate materials, once thought impossible to cut with lasers, are now being successfully converted. Having said this, laser cutting tends to create varying degrees of smoke and particulate waste and it may be necessary to add filtering systems to the cutter to remove any noxious fumes generated by some materials. Some manufacturers provide laminar smoke control as standard so as to minimize deposition of debris on the laser lens and contamination of the work environment.

Technical advances

Technical improvements and advances to the latest generation of laser cutters have included greater calibration accuracy, new user-friendly touch panel operator interfaces, faster operating speed and enhanced cutter accuracy, better z-axis co-ordination, detailed diagnostics, greater tension control and better calibration of material files.

Added value features

One of the key benefits of laser cutting technology is that, apart from die-cutting labels to shape, it can also create a whole range of additional and/or added-value features in the same web pass. Features such as consecutive numbering, micro-perforating, scoring, personalizing, kiss cutting, engraving, laser cutting of small angle corners and cutting through release liners.

Often, off-line laser die-cutting will be incorporated with slitting, inspection and rewind systems.

Narrowing down the choice of machine

When sourcing a laser cutting machine the label converter needs to have a clear idea of the type of work/applications to be produced on the machine, the complexity of the label or product shapes and the cutting demands, the materials that will most commonly be used, whether sheet or web-fed converting is required and the kind of production rates that will be demanded.

Once these factors are clearly understood it is then possible to contact one or more potential laser cutter vendors and ask them to run some examples of your labels and materials on their most relevant model. They can recommend the appropriate machine and undertake trials.

With laser cut samples of the converter’s own origination and materials, together with model details and pricing guidelines, it will then become possible for the converter to visit the machine manufacturer and see running trials of the jobs and materials, including examining the ease of importing cutter profiles and drawings into the machine.

Finally, determine with the machine supplier what levels of after-sales service support are offered and available to get an indication of likely downtime in the event of a breakdown.

DIGITAL FINISHING INNOVATION IN THE FOLDING CARTON INDUSTRY

With the on-going trend for folding cartons to be required in shorter run lengths, in more versions or variations, in a reduced time to market, or even for test marketing and trial product launches, the demands on press and finishing equipment manufacturers have been to reduce set-up times, enable quicker changeovers and increase production efficiency.

Conventional analog press manufacturers, such as KBA and Heidelberg, have certainly been playing their part in targeting the short-run package printing market with new, more efficient press models, while the 2012 Drupa show saw the launch of a number of new, innovative, sheet and web-fed folding carton presses from the leading global digital press manufacturers, including HP, Xeikon, Presstek, Xerox, Screen and Landa.

Certainly there can be little doubt that recent digital innovations have been very much about a new world of package printing; a new future that can take the folding carton sector a long way towards meeting the demands of brand owners for a more efficient, cost-effective, shorter time to market with decreased stock-holding – and a more flexible supply chain with an increasing emphasis on sustainability.

Although the evolution of both analog and digital printing technology has been making these brand owner demands ever more realistic, it was still leaving a key element in the folding carton supply chain missing – how to speed-up the folding carton cutting-and-creasing operation by reducing the turnaround between jobs. Ideally, the solution would also lead to enhanced production flexibility, more innovative and creative design possibilities and, hopefully, production cost efficiencies.

Highcon Euclid

It was to provide an answer to these challenges that Highcon developed and introduced its Highcon Euclid Direct To Pack digital folding carton cutting and creasing solution, so extending digital technology into the realms of the carton finishing process. It can also be used as a finishing unit with conventional analog presses.

Powered by their own patent-pending Digital Adhesive Rule Technology (DART), the Highcon Euclid uses precision laser optics and polymer technologies to transform the carton cutting and creasing process from an analog to a digital workflow, so eliminating the need for conventional dies and, in the process, dramatically streamlining the finishing operation. Crease lines are created in minutes, while an array of lasers with precision optics cuts with both speed and quality.

How does the Highcon Euclid work?

The Direct To Pack solution uses an entirely new technology as a means to eliminate conventional dies, delivering high quality cut and creased carton board entirely from digital data. To do this, CAD cutting and creasing information is received in two layers (one for creasing and one for laser cutting) from DXF files from standard pre-press software into, say, Esko ArtiosCAD, with whom Highcon have a commercial and technological co-operation agreement.

The creasing layer information is used to rapidly create the Highcon Dart, laying down Dart polymer rules onto a foil mounted on the creasing cylinder, instantly forming high-quality creasing rules within a matter of minutes without any need for traditional dies. This can be seen in Figure 8.11. Once the Dart has been created the Euclid is ready to start production. In total, the whole set-up takes around 15 minutes.

The second data layer is used to control three C02 lasers and an innovative scanning optical system which enables the cutting and perforating of the carton board in high quality at production speeds of up to 1,500 sheets per hour – determined by the length of the cut line, type of substrate and job complexity (number of ups) – prior to stacking.

Capable of handling materials up to B1 size (76 cm x 106 cm; 30 inches x 42 inches) and from 0.3-0.6 mm thick, accurate registration throughout the process is maintained by the machine’s feeding and transport system, with the sheets passing between the Dart foil and the Dart counter to create the sheet lines with ease, with the precision lasers then cutting, perforating and marking (if required) in one continuous smooth operation.

The sheets are finally delivered to a stacker.

There seems little doubt that this revolutionary new technology offers brand owners and folding carton converters a faster and more responsive delivery, increased versioning opportunities, shorter run lengths and more creative designs. Cut-outs and decorative cuts can also be achieved both simply and fast. And with guideline set-up cost savings of up to 80%.

See Figure 8.12

Certainly turnaround times are dramatically cut, with run lengths up to 10,000 sheets becoming more attractive and possible. Plant efficiency is increased through simplified logistics. Machine operation too, is simplified through the use of an entirely digital process and, with no dies in the supply chain, it is possible to also improve sustainability. Reduced warehousing and a lower carbon footprint also improves scorecards.

LASER SCORING OF FLEXIBLE PACKAGING AND CARTONS

Laser scoring of flexible packaging involves the use of a focused laser beam to remove a specific portion of a material’s surface, so weakening the substrate and allowing it to easily fold or tear. While a number of applications for laser scoring exist, the most prominent in the packaging industry is for flexible packaging. These applications are able to laser score a tear line into a film substrate to create an easy-open package with a controlled tear across the packaging’s top. The package film is scored to an exact depth to weaken a specific layer of the film without affecting the package’s barrier layers or performance. One of the companies providing such technology is LasX.

LASX

The LaserSharp® laser scoring equipment from LasX, provides a variety of processing applications that include straight line cross web scoring, straight line down web (or machine direction) scoring, contoured machine direction scoring, cross web patterns. The machine’s processing capabilities add any number of easy-open features to flexible packaging, like tear strips, pour spouts, recloseable bags, resealable pouches, microwaveable packages, and peel away windows. Any unique easy open feature can be designed into a package with precise score lines registered to print.

Score lines are created by vaporizing specified areas of a flexible film, creating a narrow channel in the material for a tear to follow. A laser weakens specific layers of a material to produce score lines without compromising the barrier properties of a flexible film. Straight line cross-web scoring, straight line down-web (or machine direction) scoring, contoured machine direction scoring, and cross web patterns are all achievable in a single production run.

Score lines can be precisely registered to print on a product’s package. Registration sensors and vision cameras integrated directly within LaserSharp® digital converting systems automatically control processing in response to print cues, to ensure pattern accuracy. Laser scoring equipment can be integrated into existing or new slitter/rewinders or pouching lines. Flexible packaging is ideally suited to lower power CO2 lasers, as these lasers are more than adequate for cost-effectively processing relatively thin films while maintaining a small footprint, low maintenance requirements, and high reliability.

In addition to scoring flexible packaging, the LasX multiple laser capabilities allow carton producers to cut borders of folding cartons and score fold lines, as well as slits or intricate patterns into folding cartons, in one station. Laser cut easy-open features, such as perforations, tear strips, or pour spouts to improve access to the contents without incurring the extra costs of additional tooling, can also be added. In addition to intricate patterns, the LasX Contour Creations process can also laser score fold lines and easy open features like perforations or zip-tear features.

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