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Product decoration technologies: direct digital printing

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Developments in digital inkjet printing have the potential to revolutionize the product decoration process

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Direct inkjet printing can be used on a variety of materials such as PET, wood, paper, metal, foil, glass, and textiles.

Inkjet direct decoration has evolved rapidly over-time with cylindrical and conical shapes falling well within the capabilities of the process.

Bottles, containers and tubs can now be efficiently decorated using direct inkjet (Figure 3.1).

One packaging sub-sector which has started to adopt direct ink jet printing technology is the printing of cans, bottles and other curved surfaces (Figure 3.2).

MACHINE DESIGN

The KHS Direct Print machine has been designed to be modular (Figure 3.5). As with conventional printing machines it is split into color units. In Fig 3.6 one color unit is represented by one printing carousel.

At 12,000 bottles/hour, the system has four print segments (stations) per color carousel. The system ican be upgraded by adding print segments to each carousel, eight print segments total to reach 24,000 bottles/hour, and twelve print segments total to reach 36,000 bottles/hour. This segment structure applies to all processes within the Direct Print industrial printer (bottle pick-up, bottle orientation, printing, curing, print inspection).

PRINT PROCESS

Clean, non-siliconized empty PET bottles enter the print machine via neck handling, transported from the blow molding machine or unscrambler via an air conveyor. Neck-handling has the advantage in that less format parts are required.

At the in-feed of the direct print industrial printer, bottles are spaced and fixed within bottle carriers ('pucks'). A key role of the pucks is to enable accurate print registration and a consistent flow of bottles through the system. During the whole print process the pucks keep bottles clean and airtight.

PET bottle surface pre-treatment (corona, plasma, flame, primer) is not required. Direct print inks are designed to adhere and remain fixed to clean un-treated PET.

INTER-COLOR 'PINNING'

Each print segment is equipped with a single-pass digital print head, combined with a low power UV LED lamp to 'pin' or bond the color on the bottle surface before the next color is applied. This inter-color pinning increases the process stability by freezing the ink droplets after a certain period after printing. Edge sharpness will be increased as the 'wetting' of the droplets on the surface is controlled.

LED CURING

High efficiency UV LED lamps are used for pinning as well as final curing. In contrast to conventional UV bulbs, the LEDs have some significant advantages:

Mercury free

On/off switchable within milliseconds (conventional UV bulbs need a certain warm-up phase, therefore they are normally not switched off during production. The light is only shielded by mechanical shutters)

the narrow UVA spectrum of the UV LEDs mean they do not produce any ozone

no infrared light is emitted and therefore the substrate is not subject to as much heat as with conventional bulbs.

PRINT WORKFLOW

There are some innovative developments in the direct print arena that offer users the potential to seamlessly manage their entire print workflow (see Figure 3.8).

MACHINE DESIGN

PRINT PROCESS

PET bottle surface pre-treatment (corona, plasma, flame, primer) is not required. Direct print inks are designed to adhere and remain fixed to clean un-treated PET.

INTER-COLOR 'PINNING'

LED CURING

High efficiency UV LED lamps are used for pinning as well as final curing. In contrast to conventional UV bulbs, the LEDs have some significant advantages:

Mercury free

On/off switchable within milliseconds (conventional UV bulbs need a certain warm-up phase, therefore they are normally not switched off during production. The light is only shielded by mechanical shutters)

the narrow UVA spectrum of the UV LEDs mean they do not produce any ozone

no infrared light is emitted and therefore the substrate is not subject to as much heat as with conventional bulbs.

PRINT WORKFLOW

There are some innovative developments in the direct print arena that offer users the potential to seamlessly manage their entire print workflow (see Figure 3.8).

Direct Print Powered by KHS™ for example, provides a customer-specific and secure, highly-automated artwork and color management platform which operates in the 'cloud', providing brand owners and their design agencies with a system to prepare artworks, color manage and translate artworks into the digital format for digital printing.

With a Direct Print sample printer located either at the brand owner offices or at the agency, brand owners can then print sample (proof) bottles with the correct ink, the correct printing process on the correct bottles – this enables the brand owner to see exactly what they will achieve, prior to sending the same print files via the 'cloud' to the pre-press and workflow of the industrial Direct Print equipment on-site in the bottling line.

Brand owners will be able to efficiently create new decorations, produce print proofs within minutes, and send bottle-to-bottle image variability to their industrial lines in real time – creating unprecedented flexibility and consumer engagement with high resolution white + CMYK decorations.

AN EXPLANATION OF THE INKJET CORRECTION PROCESS

Inkjet print-heads are designed to print onto flat surfaces, so when printing directly onto an object the type of shape to be printed needs to be considered – and in particular the continuity of the object’s curves in the direction of print.

A 'continuous' shape is an object whose curvature remains constant in the direction of print – so tubes, cylinders and cones are continuous shapes.

In contrast, a 'discontinuous' shape is an object whose curvature changes – an example is a tub (as used for ice cream or butter) as the container is a mixture of flat sides and curved corners making the curvature discontinuous (Figure 3.9).

Today, most of the 'direct to shape' inkjet systems are printing onto containers with a continuous curvature – like tubes and cylinders. If a cylinder is cut down one side it unfolds and flattens into a simple rectangle or square. This means that the image to be printed onto the tube does not need any image compensation as there is no distortion – the image will wrap around the tube…so essentially the printer is wrapping a 'flat' image around the cylinder.

However, the physical characteristics of the print-head create new challenges. There are three key issues – print-head symmetry, distance between nozzle rows and the number of nozzle rows. The symmetrical orientation of the tube under the print-head is important.

For example, if a print-head has two rows of nozzles, the tube should be orientated so that the rows are symmetrical either side of the centre line of the object (Figure 3.10).

This image compensation software can be taken a step further and used to print onto more complex objects with discontinuous curves such as tubs. The mixture of flat and curved surfaces means that the required corrections change during printing – often pixel to pixel.

In this case a multi-dimensional nozzle, density and screener correction technology must be implemented which can be adjusted to each surface type as required (Figure 3.13).

DIRECT DIGITAL INKJET - ADVANTAGES & DISADVANTAGES

Advantages

Direct printing onto curved or irregular shapes

Elimination of label materials and adhesives

No contact with product

No films, screens, plates or rollers to process or clean

Variable data printing on demand

Reduced waste and environmental issues

Ideal for short run lengths and faster order turnaround with rapid response to market opportunities

Print on demand with significantly reduced inventory

Disadvantages

High cost of inks

High capital cost of equipment

Low opacity and low coating weights

Potential problems relating to recyclability of printed containers

CONCLUSION

Developments in direct digital printing has the potential to revolutionize manufacturing processes in the packaging sector.

Already making inroads into mainstream container decoration, direct-to-shape printing is set to develop rapidly as the technology evolves, thereby making it suitable for a much wider range of container shapes and curved surfaces.

Digital processes deliver many advantages in the form of production flexibility and as the cost inks reduce this process will become even more appealing as a decoration system.

Intro section

Developments in digital inkjet printing have the potential to revolutionize the product decoration process. The technology is still in its infancy but it has the potential to meet demand for short-runs, personalization and variable data.

Inkjet printing is a non-impact plate-less process that prints directly from digital data and uses jets of very fine ink droplets fired at the substrate to form the same or variable images onto the product.

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Embellishments: intaglio printing

Feedimporter — Tue, 17 Nov 2020 12:55:00 +0000

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Embellishments: intaglio printing

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Intaglio printing (which has become known as gravure printing) is a specialist print finish which is predominantly used for security applications

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BRIEF HISTORY

Intaglio printing originated with the goldsmith engravers in about 1446. The images were hand engraved onto copper, gold and silver and the recessed image was filled with a black ink or enamel known as Niello and then pressed onto paper. These early prints were used by the goldsmiths to display the range of engravings available to the customer. The goldsmiths not only engraved their products, but also developed an etching method using nitric acid. In about 1640 a German engraver called Von Seigen employed a new method of intaglio printing called mezzotint, which was used to reproduce paintings in black and white and also in color. Engravers mastered the art of varying the depth of the engraving or etching which allowed differing shades of color to be achieved.

The intaglio process was further developed in the early seventeenth century when it became known as gravure printing. The process began to use metal plates which carried the etched image, which was then printed onto the substrate.

The invention of photography led to the method of transferring a photo image onto a carbon tissue coated in a light-sensitive gelatin. This process allowed the etching of an image onto a steel or copper covered rotary cylinder and heralded the beginning of the modern rotogravure process.

THE PROCESS

The process of intaglio engraving and printing is relatively simple. The image to be reproduced is engraved onto a metal surface usually of copper, brass, zinc or steel. The image is hand engraved or etched and the lines/cuts hold the ink which is to be transferred onto the substrate.

The hand engraving of an intaglio image requires considerable craft skills. The engraver uses an engraving tool called a ‘burin’ which is a steel square ended tool which is diagonally shaped and sharpened at one end. This is used to cut a series of lines which can vary in both width and depth of the cut.

The deeper the line cut, the ‘more’ ink the line will hold and the shallower the line cut, the less ink the cut will hold. This effect produces the varying tonal values (see Figure 7.1).

ETCHING

The other method of intaglio imaging is by the etching of the image onto the plate. The plate is covered in a film of acid-resisting wax called the ‘ground’.

The engraver uses an etching needle.

The plate is then placed into an acid bath allowing the acid to etch into the surface of the plate where the ground has been removed thereby creating the recessed intaglio image. This is called the ‘biting’ process.

This etching process can be repeated by identifying the areas of the image that may require a deeper line depth.

This involves applying a lacquer/varnish to these areas and re-etching with acid. This allows the engraver to vary the depth of the image to create the different tones of the image.

When the etched image has reached the required depth the plate is removed from the acid bath and the ground is wiped from the plate surface, which is now ready for printing.

MARKETS

The use of the intaglio process in modern print relates very much to security printing, particularly in the printing of paper and synthetic substrates for currency, passports, banknotes and self adhesive postage stamps.

The processes used for the production of these complex products, often involves multi-process combination presses, equipped with lithography, flexography, screen and gravure/intaglio printing and a variety of finishing processes.

Intro section

Intaglio printing (which has become known as gravure printing) is a specialist print finish which is predominantly used for security applications.

Intaglio printing is the opposite of relief printing in which the image to be printed is etched or engraved below the surface of a print cylinder or plate. The printing process is carried out under pressure. The ink is consequently drawn up from the recesses onto the substrate and dries leaving a slightly raised image, which can be detected by feel.

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The potential of laser die-cutting and digital finishing

Feedimporter — Mon, 16 Nov 2020 10:19:00 +0000

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The potential of laser die-cutting and digital finishing

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The potential of laser die-cutting and digital finishing

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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:

To set-up and run each laser cutting machine to optimise die-cutting performance and register.
To understand how pre-printed webs and workflow solutions enable re-registration through laser cutters
To find out how to maximise value with complex shapes, cut-outs and laser etching capabilities.
To compare laser die-cutting results from four different laser cutter manufacturers.

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:

The technology offers 100% savings in cutter tooling. No dies are required, whether flat, rotary or flexible. If a converter has enough die and size changes a day then laser cutting very soon starts to become a very viable option.

Because there are no tools, there are no production delays for time needed to make the tools.

Laser cutting systems can take any vector-based digital image and import it into the operating software to set up a job.

Today’s best-in-class laser cutting systems can complete set up from imported digital images in just a few minutes.

Tool-less non-contact laser production offers multiple depth cutting possibilities and can include kiss-cutting, thru-cutting and perforation in one pass. It is especially suitable for applications with feature locations, tolerances, size or material characteristics, etc, that would typically be difficult or impossible to provide using traditional label dies.

Converters using laser cutters estimate that the savings in set-up waste can be as high as 60%. Because laser cutting is an entirely digital process, pattern changes are simple, requiring only edits to drawing files without any downtime for set-up or die creation. Undoubtedly a key benefit in today’s challenging sustainability environment.

Existing converter users also estimated that there can be as much as a 40% - 60% saving in time and labor costs – a significant element of any converter's costing.

Lasers today can be used to cut all shapes and sizes. There are generally no size limitations, except that the more labels across the web and the more complex shapes that need to be cut, the lower the web cutting speed will be.

With few exceptions, lasers can cut most types of substrates. PVC is not possible due to the toxic gases given off when cutting. Aluminium foil is also not possible as its wavelength is too close to that of a C02 laser. Otherwise, pretty much anything.

Apart from cutting, laser systems can be used to etch OCR fonts, one and two dimensional bar codes, serial/sequential numbers and codes. The type of information that can be laser-etched is limitless – and all in one pass with the cutting operation.

Laser cutters can be used off-line with re-registering of webs, or linked in-line to digital or conventional label presses.

There are major possibilities to provide added-value solutions with laser that cannot be achieved with conventional die-cutting, particularly when used to cut more intricate and complex shapes.

Laser cutting can also be combined with other laser processes such as perforating, scoring, kiss-cutting, etching and ablating

When using digital printing from inkjet or Xeikon presses there can be an unlimited print and cut length with laser cutting to provide extended label/banner opportunities.

Again with inkjet/Xeikon technology, jobs can be batched across or along the web to maximise short-run production, enabling multiple label size and shape changes in one run.

Laser cutting can be used to convert difficult materials, such as abrasives and adhesives, with ease

Varnishing, coating and laminating finishes generally all cut well and may even improve the cut quality. PET laminates are said to give especially good results.

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:

Maximum web width 330 mm

Full rotary cutting

Kiss cutting and through cutting

2 X 200 Watt Synrad Firestar sealed CO lasers

Smoke/debris 4 stage filtration and exhaust

Digital Die Shop software

Running speed up to 60 m/min.

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:

Working web width typically 350 mm

Can operate in-line or off-line

Efficient, high reliability and low maintenance CO laser, 200-1000 watt

Delta touchscreen features and interactive machine graphic

Variety of cuts – including perforate, kiss-cut, through-cut

Servo-controlled laser module re-positioning

Laser speeds vary, up to 8 meters per second. Finishing system runs up to 60 m/min.

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:

Working area 350 x 350 mm

CO2 10600 nm laser

Filters, remove 99.997% of all gas and dust

Work process includes die-cutting,micro-piercing, easy opening, engraving, coding

Processes paper, PET, PP, TNT, etc.

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:

Web widths 210 mm, 350 mm and 500 mm

Running speed up to 100+ m/min

Cut-to-print XY registration to within +/-0.1 mm

On the fly job changeovers

Sealed CO laser with a 210 micron spot size

Application software – Optimization, Cut-And-Stitch, Estimator

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:

Maximum width 360 mm

Power range from 250 to 350 Watts

Speed up to 80 m/min

Semi-sealed CO laser with 3 axes Galvanonmetric system

Laser bean spot from 240 to 360 µ

Die-cutting of labels and sheets

Engraving, punching, and progressive and regressive numbering or coding.

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:

Zenna laser die-cut module

Web widths of 330 and 500 mm

In-line or off-line options

Running speed up to 60 m/min (depending on material)

Maximum substrate thickness 500µ

Module is designed to fit into the DC330 or DC330 mini converting lines, but can also be custom integrated

Fully digital position system which is superior to existing analog laser systems

State-of-the-art exhaust system eliminates brown edges, with less odor.

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.

Intro section

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.

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Options and opportunities for digital print finishing

Feedimporter — Mon, 16 Nov 2020 09:53:00 +0000

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Options and opportunities for digital print finishing

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A look at finishing digitally printed labels in-line and off-line

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So let’s look at conventional label finishing first. References to some of the newer solutions for wider format folding cartons and flexible packaging follow later.

LABEL FINISHING

Currently, around 80% to 85% of all the 2,000 or so digital label presses that are installed and operational in the global label industry today are running with off-line finishing capabilities. That has been the route that the majority of HP Indigo customers have chosen, with their partner suppliers providing the digital finishing equipment. Other digital press manufacturers such as Xeikon are using different solutions and aim to provide a complete printing and converting line.

Some of the latest inkjet presses are now being supplied with in-line digital finishing. However, at the present time, the total installed base of stand-alone digital label presses is still predominantly with off-line conventional finishing. This can be seen in Figure 7.1.

IN-LINE OR OFF-LINE

Working offline certainly gives the opportunity to have much more flexibility. The more complex the label job, then the more the converter to-date has looked at an off-line finishing scenario.

As digital presses get faster (up to 60 or 70 meters a minute or more) so the converter will have a very good reason to want to run in-line. It will largely depend on the type of work being produced. ABG International for example, have to date installed well over 700 finishing lines in digital label converting plants in some 65 countries – relatively few of those have been in-line systems.

If jobs predominately just require flexo varnishing and die-cutting, then in-line may well be the best option. The more processes required in the finishing line (foiling, foiling, embossing, etc), the more it is likely to slow the digital press speed down, which negates the need to have a press running at 50-60 meters or more a minute. If changeover and set-up on the finishing line is longer than the press changeover time, then off-line finishing probably makes the most sense.

In-line finishing however, does offer key advantages. The converter will get from the beginning to the end of the job in one operation. With the new generation of faster digital label presses the ability to print and ship without a separate finishing operation is a definite advantage – providing the press and output is not substantially slowed down by the finishing requirements. Certainly this is the route that, say, Xeikon and Nilpeter have followed.

Laser die-cutting in-line is also becoming ever more attractive as inkjet speeds rise, and also when jobs can be batched or ‘Ganged’ on the web. Doing everything in-line also means that it is possible to modify the pre-press or image to match the die-cutting or the hot stamping, or to a screen edge. That’s not possible if the job has already been printed and just requires finishing off-line.

The choice of in-line or off-line may also depend on how many digital printing machines a converter operates. With multiple digital printing presses it may be more feasible to have one or two off-line finishing systems servicing 3, 4 or 5 digital presses – even providing finishing for conventional presses where more complex finishing operations are required.

What is important is that the converter looking to invest in digital printing technology initially makes a good case for either in-line or off-line finishing depending on his customer requirements, the markets served, the complexity of work undertaken, the number of digital presses, etc.

RANGE OF FINISHING OPTIONS

While a die-cutting capability – which may be flatbed, rotary, magnetic cylinder or increasingly, digital using laser cutting – is a primary requirement of almost all digital label presses, it is almost certain that other finishing capabilities will also be required for many end-use applications. Certainly, the minimum that the converter will need to have, whether off-line or on-line with digital finishing, is die-cutting, but the great majority of the presses will all also have a requirement to do varnishing – commonly UV flexo varnishing.

So, effectively, there are the two minimums for all finishing operations on label digital presses: die-cutting and varnishing. Almost all the finishing machines installed to date have both these options as standard, as well as web-handling, edge trim, matrix strip, slitting and rewinding. In essence, a basic off-line finishing machine for self-adhesive labels will likely include:

An unwind

Web handling

UV flexo varnishing

Semi-rotary die-cutter

Liner score/edge trimming

Matrix stripping and matrix rewinding

Slitting and rewinding into finished rolls.

Depending on the market sectors that the converter is involved with, so other finishing operations will be required. Hot or cold foiling for the cosmetics or wine and spirits sectors; possibly embossing for those same sectors as well; maybe sequential coding or numbering for pharmaceuticals; perhaps a vision system for web inspection; sometimes over-laminating. All of which will add to the converter’s digital print finishing capabilities.

Put together, a label converter may wish to build a finishing capability that will differentiate them from competitors, or create a finishing solution to suite a particular market or markets – even a key market application or job. Key tools for this differentiation may then look to include some or all of the following features:

In-line finishing

Full rotary die-cutting

Screen printing

Spot varnishing

Cold foiling, hot stamping, embossing

Carton, blister pack, shrink sleeve,

pouch or sachet finishing

Vision system

Laser die-cutting

When looking at building a digital finishing line there are other items which the converter may well wish to consider. These are: whether the die-cutter for digital finishing can use existing tooling from the converter’s conventional presses. Similarly, can the foil units use most of the existing tools from the conventional presses and whether they incorporate foil saver and dispro adjustment?

Digital finishing lines will all obviously require a rewinder, or more commonly a slitter rewinder – with automatic tension adjustment – while stand-alone finishing lines will additionally need to incorporate an unwind unit with web guide for perfect registration. Some may be configured to incorporate corona treatment, chill drum and web cleaning.

A guide to the usage of the main finishing capabilities on the current installed base of standalone full-color digital label presses can be seen in Figure 7.2 which is based on research in recent years by InfoTrends and on recent industry analysis by Labels & labelling Consultancy.

In addition to the specific finishing capabilities shown in the chart, some label converters with digital printing presses may wish to incorporate one or more conventional printing processes into the finishing line to add value or special effects for, say, high-quality cosmetics or wine label applications.

Options may include full rotary or semi-rotary flexo with UV or infra-red drying; an optional spot varnishing station with servo-driven register control; flatbed or rotary screen module (the cost of the mesh, frame, pre-press and set-up will be cheaper with flat screen). Rotary screen may well be considered if large volumes and increased speed are required.

Cold foiling is also now successfully being undertaken with inkjet in the finishing line. The inkjet head puts the adhesive down and so cold foiling is effectively done digitally. The down side at the moment is the cost of the consumables – the inks, the varnishes, the adhesives are far, far more expensive than customers and converters are traditionally used to paying for them. It’s a cost factor; it’s the ink suppliers and the adhesive suppliers that are going to have to drive the price down further before the process is to become much more successful.

Looking across the key suppliers of finishing lines for digital label printing – such as ABG International, Grafisk Maskinfabrik, Delta Industrial Services, Cartes and SMAG, there are also a range of additional optional label finishing units that can be incorporated.

Some narrow-web label converters may wish to use their digital printing and finishing lines for the converting of small folding cartons, packaging foils and sleeves. Both semi-rotary and full rotary carton units are available from some of the leading finishing line suppliers. Semi-rotary offers lower tooling costs and easier die storage. Full rotary gives a higher throughput.

Depending on the manufacturer, other options can include hot stamping (see illustration below), missing label detection, waste shredding, slot die, undercut scoring, folding, turret unwind/rewind, ultrasonic welding, conductive inkjet printing, coating, hot and cold lamination, fully integrated camera inspection systems, JDF connectivity to the DFE and fully automated flexible die load/unload.

As can be seen, pretty well any finishing technology that a converter may require can now be supplied by one or more manufacturer. The converter is therefore well advised to look at what different manufacturers can offer and match these to their specific production and customer requirements.

The potential to make use of such options to add value and increase profitability is greater today than it has ever been.

MODULAR SYSTEMS AND SUPPLIERS

Most suppliers (probably all) of digital print finishing/converting equipment offer modular base systems to minimize initial investment but which can be added to or expanded (with any of the options already outlined) as and when the converter grows or when customers or applications demand additional finishing or added-value capabilities. Most will also offer options for in-line or off-line finishing equipment. So let’s look in more detail at the key digital label print finishing equipment suppliers and what machines and models they provide.

ABG INTERNATIONAL DIGICON FINISHING EQUIPMENT

Digicon-Lite

For converters looking for an entry level machine to convert digitally printed webs ABG International offer the Digicon-Lite (shown below).

Despite the small foot-print of this machine it is still capable of carrying out varnishing, coating and converting functions

Digicon Series 2

At the other end of the market requirement for digital finishing equipment the ABG International Digicon Series 2 machines are claimed to be amongst the most advanced and diverse on the market. Being fully modular the Series 2 provides options including hot foil, cold foil, flexo stations, flatbed applications, screen printing, lamination modules, camera systems and a whole lot more. Modular units allow retrofitable options from hot foil, cold foil, flexo stations, flatbed applications, screen printing, lamination modules, camera systems and other options as required. Key technical specifications for the Digicon can be seen in the table below:

The Digicon Series 2 machine (example shown below) combines semi-rotary technology with accurate re-registration modules for a variety of digital converting applications.

DELTA INDUSTRIAL SERVICES SPECTRUM

Delta Industrial have a digital print finishing unit (the Delta Spectrum®) which they describe as the ultimate finishing solution.

Technical specifications include options for flexible die technology in semi-rotary mode or traditional die-cutting in full rotary mode. The unit can be used for in-line or off-line production.

Like other suppliers they have a range of finishing modules that have been developed over the years – all of them servo-controlled – and the company will custom design and automate to a customer’s specific requirements: as simple or as complex as required to meet specific label finishing needs. Options available include varnishing, die-cutting, cold foiling, embossing, spot varnishing, turret unwind/rewind, folding and waste stripping. Process modules may be easily added and moved.

To help guarantee quality Delta Industrial Services can also incorporate a vision system, either for visual inspection by the operator, or fully automatic, with automatic detection with reject capabilities.

Standard press width is 330 mm (13 inches), but other widths are available on request. For converters that want to add a 2D barcode or something at the last instant, Delta can offer in-line digital printing typically using inkjet print heads that are UV cured. The Delta Spectrum® can be seen in the following illustration.

SMAG DIGITAL GALAXIE

Also on the market is the Digital Galaxie from SMAG, another of the suppliers to the digital printing and finishing sector. SMAG is offering several product ranges from simple, compact and productive entry level with semi-rotary or full UV flexo varnish, lamination and semi-auto die-cutting up to a high end state-of-the-art solution, the Digital Galaxie, which is a more flexible machine with different types of add-in modules – such as semi-rotary or flatbed foil, embossing, flatbed screen, lamination and cold foil and a 100% inspection system in cooperation with AVT – to bring the line closer to the capabilities of a conventional press And finally a priming range in order to prime the material in or off-line.

The Digital Galaxie has been developed on the Galaxie press base (of which more than 200 units have been installed) but adapted for digital printing. Thanks to its silk screen technology, the machine is able to bring added-value to products – including matt inks, tactile effects and thermochromic effects.

Maximum web width is 350 mm, with a running speed of up to 45 m/min.

SMAG has more than 80 installations in Europe and worldwide of the Digital Galaxie converting machine.

GRAFISK MASKINFABRIK DIGITAL FINISHING MODULES

Another company with a substantial installed base (now over 200 machines) of digital finishing equipment is Grafisk Maskinfabrik, whose range of machine models includes the DC330, the DC330mini, the DC500, the LS500 and the XP560 with web widths up to 560 mm. Specifications can be seen in the following table.

Standard finishing options on these machines provide for varnishing, die-cutting, hot and cold foiling, embossing, waste stripping, screen printing, RFID, slot-die, laser cutting, hot glue and flexo printing. Other options available are sheeting, either in-line or off-line, lamination, self-adhesive lamination, UV lamination, missing label inspection, etc.

Non-label applications that can also be provided in the range are shrink sleeve and IML.

CARTES GT360 SERIES

Cartes provides modular machines configurable with hot stamping, silk screen printing, embossing, flexo varnishing, flat and laser die-cutting.

Machines are adaptable to all production needs thanks to their modularity and are renowned for the material saving – even on short runs – their mechanical toughness, high accuracy (even when printing at the maximum speed), their energy saving, and the high levels of operator safety.

The Cartes GT360 Series machines come with a web width of 360 mm and can run at up to 15,000 cycles per hour, either in-line or off-line. Apart from self-adhesive label production the machine can convert a range of other materials, including demanding materials like sandpaper.

Specifications for the GT360 are as follows:

Each printing unit works as an independent module, making it possible to insert, replace or add units irrespective of the original machine configuration.

GONDERFLEX INTERNATIONAL ROTOWORX 330

Previously part of the Durst digital printing and converting portfolio, the Rotoworx digital label converting and finishing unit was recently acquired by Gonderflex International, who have launched the new Rotoworx 330 semi-rotary die-cutting machine, with a flexographic unit performing spot or flood coating with redesigned UV and IR dryers.

The unit also features a new enclosed doctor blade system and equipment for cold foil lamination. Optionally, the machine can be fitted with a rotary sheeting station, shingling conveyor, in-line booklet labels production, semi-rotary hot foil stamping and rotary screen printing.

LEOMAT DIGITAKT 330 SFR

The Digitakt 350 SFR has a matrix rewind, printing unit, semi-rotary die-cutting unit, an AVT camera inspection system, cutting unit and rewinding unit. The machine is assembled modularly and allows simple subsequent integration of additional modules like hot stamping, screen printing, additional die-cutting, in-mold delivery system, label dispensing systems, etc.

BAR GRAPHIC MACHINERY BGM ELITE FDTR

Standard features on the Bar Graphic Machinery BGM Elite are being able to print to register, die-cut to print re-register and print-to-print re-register; the servo-driven print stations are equipped with self-positioning print cylinders enabling automatic print registration set-up.

The machine is fitted with interchangeable UV and IR curing cassettes, while dual servo-driven die stations with removable anvils enable all converting options to be achieved.

MATCHING FINISHING TECHNOLOGY TO MARKETS

The configuration of a digital printing finishing/converting machine is really dependent on the markets in which the converter is working: the main markets being food, wines and beverages, cosmetics/health and beauty and pharmaceutical.

Food

For the food industry most of the finishing machines installed to date tend to be relatively simple with a basic configuration of flexo varnishing, cold foiling and semi-automatic die-cutting.

Wines, spirits and beverages

For the wine, spirits and beverages markets the finishing machines are generally more complex – more and more features on them. With digital becoming increasingly in competition with conventional presses the same finishing features are being added to digital converting equipment in order to fight against conventional presses. So, in this market, there is now a lot of hot stamping, which may be flatbed hot stamping or semi-automatic hot stamping, both systems bringing their own advantages and disadvantages.

Cosmetics/health and beauty

Like the wines and spirits sector, cosmetics, health and beauty labeling is becoming increasingly complex. Again, more and more converting/finishing features are being added to the digital lines so as to compete with conventional printing – hot stamping, embossing, etc, in particular.

Screen printing technology is also very useful in the cosmetics market (wine too) in order to bring some added value to the finished products.

Pharmaceutical

In the pharmaceutical market there is commonly a requirement for screen to be added into the digital finishing line; sometimes flexo and from time to time, foiling. Anti-counterfeiting features may be added with a hologram stamping unit. For the same market it may also be necessary to integrate a 100% camera inspection system. Additionally a digital Braille system may be added – this is an inkjet type system that digitally puts down a raised Braille image.

WHERE NEXT FOR DIGITAL LABEL, CARTON AND FLEXIBLES FINISHING?

Digital print finishing has come a long way over the past ten years or so. Laser die-cutting is taking this even further, but where can we expect digital print finishing to be in the not too-distant future?

Undoubtedly, converting has been seen as something of digital print’s Achilles’ heel. Although digital print is instantly variable it still takes time to manually set up a pressure-sensitive label converting line, particularly where multi-process work is required.

However, according to ABG’s Keith Montgomery, speaking at a recent HP Indigo event in Tel Aviv, we can soon be looking towards the upcoming automation of the digital converting process. ‘The Idea,’ he explained, ‘is for full automation - to automatically load and unload flexible dies, to incorporate laser finishing, automated set-up of back-scoring, and repeatable auto-positioning of cutting wheels and slitting knives. We will also be integrating turrets into digital converting lines to improve uptime, and we will be looking at digital hot foiling before too long.’

Montgomery gave the example of typical manual changeover times: two minutes for a flexible die change, two minutes for back scoring, 5 minutes for slitting knives - 9 minutes in total. ‘With an automated set-up this takes just 45 seconds. If you’re saving even eight minutes per job, on 12 jobs a day that’s 1.5 hours across a shift. ‘

The driver for this future of full automation is JDF connectivity. ‘The MIS sends files to the digital converting system with information on repeat length, rewind shaft diameter and all other relevant data. The die line is sent straight to laser. The planning system knows which machines are free and fires the file to any available machine. JMF automatically updates the MIS with accurate job costing information and updated production information, all in in real time.’

Digital print finishing will almost certainly be different and more automated in the future. Laser cutting and other forms of digital print finishing will become widespread. With current progress in laser die-cutting now making the technology a more regular and commonplace part of finishing, it was therefore decided to devote a whole article to this. See the potential of laser die-cutting and digital finishing.

Let’s take a look at some of the companies and developments taking place in the wider format conventional finishing of digitally printed folding cartons and flexible packaging produced on the latest generations of package printing presses from HP Indigo, Xeikon, Screen Europe and Landa.

AB GRAPHIC INTERNATIONAL EDALE DIGICON 3000

A joint development project between Edale and AB Graphic International (ABG), the Digicon 3000 is a 762 mm wide finishing system that enables printers to convert pressure sensitive labels, flexible packaging and folding cartons printed on the new HP Indigo wider format digital presses.With both semi-rotary and flatbed options available the 3000 offers a choice of different finishing solutions.

Both options can be integrated into any Digicon configuration and can also be retro-fitted to existing Digicon series 2 machines. With a wide range of modular options for digital finishing, including varnishing, screen printing, embossing and hot foil amongst others, A B Graphic can now offer a variety of finishing solutions for digitally printed wide format cartons and flexible packaging.

By combining high end embellishments with low cost tooling, quick job change overs and minimising waste A B Graphic have been able to introduce the perfect solution for short run folding carton work.

The two companies together bring more than 100 years of combined technical expertise: ABG having worked with HP for more than 15 years and Edale through its collaboration with Agfa Graphics for more than 12 years. Whilst the Digicon 3000 will be manufactured by Edale, the machine will benefit from the companies' combined intellectual property. Working together has enabled the two companies to create an advanced product that benefits from the respective technology strengths of Edale and AB Graphic International. As a result the Digicon 3000 is packed with innovations that will serve to enhance and broaden the applications possible in mid web digital label and packaging printing,.

Specifications for the Edale Digicon 3000 are as follows:

KAMA PROCUT 53

Initially introduced at Drupa 2008, the KAMA ProCut 53 was presented as the world’s first automatic flatbed die-cutter, with a sheet format of 530 x 400 mm. This machine provides KAMA with cutting solutions up to their existing B2 and B1 size machines. The suitability of the ProCut 53 for finishing digital printed cartons has attracted the attention of the leading digital press manufacturers and close working relationships now exist with HP Indigo and Xerox as solution partners.

The ProCut 53 provides a flexible solution for all finishing tasks within the 530 x 400 mm sheet size, including cutting, creasing, perforating, kiss-cutting, cold embossing and Braille and is claimed to be profitable even with small and personalized runs, be it printed media or printed packaging, offset or digital printing. Specifications for the ProCut 53 are shown below.

BOGRAMA ROTARY DIE-CUTTER

Compatible with Xeikon Folding Carton Suite production is the Bograma Rotary die-cutter that has been developed for single-sheet folded box processing and for thin, folded products, using flexible dies. The machine can punch, kiss cut, perforate, crease and deboss, either manufactured one or multiple-up. A maximum product thickness of 0.5 mm can be punched. Formats can be processed between A4 and a maximum sheet size of 550 x 750 mm. The maximum production capacity (depending on material) is at 12,000 cycles / h.

In-line configuration of the die-cutter (as shown with the Xeikon folding carton press at Labelexpo 2013) is naturally the most efficient way to accomplish several work steps in one single step, thus achieving high performance. Automatic discharge of the section grids while at the same time breaking out the inner cuts optimizes production even further. Technical specifications are shown on previous page.

DELTA INDUSTRIAL

Delta has developed several solutions for the package and pouching needs of customers. Applications include hot seal packaging, cold seal packaging, reciprocating heat seal packaging, and part placement packaging options and are available as both standalone machines and quick change components, thanks to their modular design.

EMMENDINGER MASCHINENBAU

This company provides a high-speed punching and embossing machine that is used by companies in the packaging, dairy and beverage industries.

The machine punches small shapes out of unprinted and printed aluminium, paper and plastic foils, directly from reels, which may then be used as sealing lids or labels.

Applications include sealing lids for yoghurt and pro-biotic drinks and beer bottle neck labels. The machine provides capabilities for embossing, perforating, pin-perforating and doming, and quick changeovers between tools that enable easy handling.

Intro section

Digital print-on-demand color label printing today is carried out with liquid toner, dry toner and inkjet engines which print on a web of, predominately, self-adhesive label stock in four or more colors. Once printed, the web needs to be die-cut to produce the individual labels for rewinding and subsequent label application. This die-cutting operation may be undertaken in-line as part of the digital label press or off-line as a stand-alone digital finishing operation.

While digital label printing and finishing is already well established, digital printing and finishing of folding cartons and flexible packaging webs has, to date, only been a very small part of the digital printing revolution, and predominately undertaken with narrow-web presses. Laser-cutting technology for labels – and, now incorporated into digital finishing for folding cartons – is much newer in terms of take-up and installations and will undoubtedly have a much more prominent place in the future.

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Glossary of die-cutting and tooling terminology

Feedimporter — Fri, 13 Nov 2020 11:52:00 +0000

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Glossary of die-cutting and tooling terminology

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Understanding the many different forms of die-cutting and tooling for label converting

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Suppliers are welcome to submit further terms so that these can be added to the listings below in subsequent publications.

AN ALPHABETICAL GLOSSARY

Abrasiveness – The tendency of some papers, surface coatings, treatments or inks to abrade or wear away die edges, slitter wheels, printing surfaces, etc., by friction.

Air eject cylinder – Developed as an alternative to the more expensive male and female cutting systems for long runs and the solid rotary die-cutter with rubber inserts and without any waste control. The system is making use of so-called air forks, to blow air (6 – 8 bar) into air channels. These air channels, are linked to bores in the cavities. Die-cutting of the holes and blowing out of the waste into a stainless steel vacuum box is done simultaneously.

Anvil position – The cutting cylinders (rotary die, flexible die, etc.) is placed in the bottom position of the cutting unit, whereas the anvil roller is placed in the top position of the cutting unit.

Anvil roller – Hardened steel roller upon which the bearers of a rotary die, magnetic cylinder, perforation cylinder, etc., run. Normally, this cylinder is placed in the bottom position of a die station. However, for certain jobs it is necessary to place the anvil roller in top and the cutting cylinder in bottom position. In case of a support roller the anvil roller would be in the middle position.

Anti-stick coatings – Coatings, engineered to reduce the ability of other materials to stick to them. For certain applications such as hot-melt adhesives, multi-layered labels and labels with high application of adhesive, tooling suppliers will offer the possibility to coat the dies. These coatings should prevent adhesive and ink adhering to the cutting edge and adhesive bridging taking place between the label and the waste matrix.

Axial – Consider a cylinder. The top of the cylinder is a circle. A radius is a line drawn from the centre of the circle to the border or circumference of the circle.

Movement parallel to a radius is called 'radial movement'. The axle of a metal cylinder with shafts on each end may have movement parallel to the axle, that is, from one shaft to the other. This is called 'axial movement'.

Axis – Axis of revolution of the gear; center line of the shaft.

Backlash – Is the striking back of connected wheels in a piece of mechanism when pressure is applied. Another source defines it as the maximum distance through which one part of something can be moved without moving a connected part. In the context of gears backlash, sometimes called lash or play, is clearance between mating components, or the amount of lost motion due to clearance or slackness when movement is reversed and contact is re-established.

For example, in a pair of gears backlash is the amount of clearance between mated gear teeth.

Bearings – The hard rings, often including balls or rollers, which provide a smooth rotary movement to cutters and printing cylinders that come into contact with each other during printing and die-cutting.

Bearing block – A block with internal bearings that holds the cylinders (magnetic cylinder, rotary die, anvil roller, etc.) in position in a die-cutting station.

Butt cut labels – Rectangular labels in a continuous web, which are separated by a single knife cut through the label and/or liner across the web. No matrix is removed between the labels, as is the case with die-cut labels. Separated individual labels on a backing liner are applied by hand or to its application to a container, product or surface.

Back slit – A cut in the release liner or backing, usually along the web, but can be on the back of sheeted pressure-sensitive laminate to allow the face stock to be easily peeled away by hand when die-cutting has not be used.

Case hardening – Case hardening or surface hardening is the process of hardening the surface of a metal object while allowing the metal underneath to remain soft, thus forming a thin layer of harder metal (called ‘the case’) at the surface.

Cavity – Any enclosed shapes on a rotary/flexible die.

Cold-foiling – A more recent development of hot-foil blocking, the cold foil process makes use of a print unit to print a special adhesive on the label web where a metallic effect is required. When the metallic foil is brought into contact with the adhesive it adheres to it to produce the printed foil design on the label.

Converting process – in package or label production, converting covers any process performed to manufacture a complete package or label from a raw material or an unfinished material. The process of transforming rolls of self-adhesive material into labels on a release liner (carrier) presented in rolls or sheets, so as to enable end users to apply them to products, packages or surfaces. This process includes slitting, die-cutting and matrix stripping operations, sheeting, and may also include printing.

Cross cutting – Cutting across the web.

Cross perforations – Perforations across the width of a continuous web for easy separation of individual sheets and/or fan folding of continuous labels. Also any perforation applied at right angles to a label or page, depending on its printed format.

Crush cut – A cut made using a rotary blade in contact with an anvil or base roll.

Crush cutting – Commonly used for adhesives and some papers. The score is a circular blade cutting against a hardened steel anvil. The circular knife then ´crushes´ the web against the anvil. Generally, slit edges are not of the highest quality, but crush cutting makes up for it in quick and easy set-up procedures.

Cutter bevels – In die-cutting, the angle of the material supporting the peak of the cutter. The smoothness of the bevel sides directly affects the amount of pressure that is required to penetrate the laminate surface – see cutting angle.

Cut & Tie – The term used when describing a perforation. The cut penetrates through whilst the tie remains to hold the material together.

Cutting station/unit – The part of a label press that contains the equipment to cut a shape or pattern into a given material. A cutting unit includes an anvil roller and/or support roller rotatable on a machine frame about an axis of rotation. The anvil roller has an anvil surface. A cutting tool is mounted on the machine frame for rotation about an axis of rotation, with a cutter interacting with the anvil surface and with supporting rings which are held on the cutting tool and support it relative to the anvil roller with their supporting ring surfaces and/or vice versa.

Cut-to-shape – Is originally a philatelic term referring to a postage stamp or postal stationery (printed stamp image) that has been cut to the shape of the design, such as an octagon, circle or oval, instead of simply cut into a square or rectangular shape.

Die-cutting – The process of cutting a label shape with a die. Most self-adhesive labels and some wet-glue and in-mould labels have to be die-cut to shape as part of their manufacturing and finishing procedure. Depending on the type of label and the printing and/or die-cutting requirement, the operation may be performed using high or hollow dies, flat dies, rotary dies, flexible dies or most recently with digital die-cutting (laser cutting).

Dial gauge – A dial gauge is a precision measurement commonly used to measure machined parts for production tolerances (run out). Dial gauges are capable of producing extremely fine measurement values. Plunger instruments are generally used in conjunction with a clamp or stand which holds the gauge in a fixed position in relation to the work piece. The work piece is then rotated or moved to take the measurements.

Die life – Meterage expected from a new die or that expected following a re-sharpening of a die. Estimates of die life depend on machine setting, type of label-stock, type of adhesive and on operator handling. Estimates of meterage from a die may vary considerably from company to company, machine to machine or job to job.

Die line – A blueprint. Drawing or computer-generated layout of the cutting shape or shapes of a die. Maybe supplied with artwork as an overlay, as a blue line on the base artwork or supplied as computer-generated data on disk, CD or transmitted electronically.

Die strike – The impression left on a backing liner after being converted by a cutting die.

Die wipe – A test to check the evenness of a rotary or flexible die cutting pattern on a backing liner. A solvent pen/marker or fine colored powder is wiped over the silicone surface where a die impression is evident. Where the die has penetrated the silicone coating, the ink or powder stains the backing highlighting unevenness in the cutting depth which can cause the waste stripping matrix to break (see FINAT test method 23 + 23b).

Distortion – A change in the dimensions of an object to compensate for change in length when a flexible die is wrapped around a magnetic cylinder (to be calculated by your tooling supplier.

Dual height – Two different cutting heights combined in 1 tool, possible in both solid cutting tools and flexible dies. In a die drawing, it should be clearly indicated which cutting lines are cutting the different layers of material.

EDM dies – Rotary cutting dies produced using electronic discharge machining (EDM) by eroding the cutting lines. The hardening process takes place before the EDM process thereby eliminating possible distortion of the cutting lines/image. Consequently, these type of rotary dies generally will have a higher accuracy than milled dies.

Ejection rubber – A variety of materials used for facilitating the flatbed and rotary cutting process. These materials used vary in thickness, structure and hardness (shore). It is important to use ejection rubber that is slightly higher than the actual height of the cutting line. This will cause compression (sufficient energy and ejection force) on the rubber thus ensuring complete ejection of the cut out part.

Face cut label – Any pressure-sensitive label in which the face material has been cut to the liner. A die-cut label product from the waste matrix around the labels has not been removed.

Flex – The deflection of rollers or cylinders in a printing press. Also describes the bending qualities or characteristics of any material, including printing plates. See deflection.

Flexible dies – A thin, flexible steel die-cutting ‘foil’ or plate for use on magnetic cylinders, magnetic base or other special die-cutting systems. Flexible cutting dies are etched from specially formulated steel ranging from 0.5 – 1.5 mm in thickness. Flexible dies are lower in cost than solid dies and the economics of use become more attractive as the complexity of the label shape increases. The life is much the same as for a solid die, providing cleanliness, setting, anvil condition, adhesive and label design are properly controlled. Flexible dies are available today with a wide range of surface treatments and provide good results with a wide variety of materials.

Friction – is the force resisting the relative motion of solid surfaces and is usually proportional to the amount of contact force which presses the surfaces together as well as the roughness or the texture of the surfaces.

Hardness – Hardness is a very important property of tool steel that is developed during the heat treating process. It is not one of the inherent properties of tool steel. Hardness is developed through the addition of carbon.

Heat resistance – The ability of tooling steel to resist softening when exposed to heat while in operation. This is a very important property in high-speed steel tools. Excessive heat in a turning or milling operation can lead to the softening of the tool. This softening allows the tool to dull or chip causing premature failure.

Hole punching (pinfeed) is normally used for making EDP holes but other shapes are also possible. The holes are cut by using either a male / female system or using a shaft with movable EDP rings. The latter is used in anvil position to cut onto the face material and the waste is being removed by the waste matrix when stripping the face.

Hot foil unit – The part of a label press that contains the equipment to hot foil self-adhesive material.

Induction hardening – A form of heat treatment in which a metal part is heated by induction heating and then quenched. The quenched metal undergoes a martensitic transformation, increasing the hardness and brittleness of the part.

Journal – The shaft on the operator and gear side of a cylinder that is supported by a bearing.

Key – In mechanical engineering, a key is a machine element used to connect a rotating machine element to a shaft. Through this connection the key prevents relative rotation between the two parts and allows torque to be transmitted through. For a key to function the shaft and rotating machine element must have a keyway, which is a slot or pocket for the key to fit in. The whole system is called a keyed point. A keyed point still allows relative axial movement between the parts.

Kiss cut – A die-cutting operation in which self-adhesive face material is cut through to the release liner backing, but the liner itself is not cut.

Laser hardening – Used as an alternative to the more common surface treatments, some suppliers of flexible dies also offer laser hardened dies. Laser hardening is not offering any reduction in the friction coefficient, but does offer a partial increase in hardness at the tip of the cutting edge. The increase in hardness depends on the carbon content in the steel and not on the energy put in by the laser.

Magnetic cylinder – A stainless steel-based cylinder having a series of permanent magnets glued around its periphery and used in die-cutting to hold flexible dies in place. Magnetic cylinders will fit on to any press that takes rotary dies, and there are no size limitations outside of those relating to the press dimensions. They are installed in exactly the same way that conventional rotary dies are installed.

Matrix waste – The skeleton of face material and adhesive waste surrounding self-adhesive labels after die-cutting. The matrix waste is normally removed on the press converting line by stripping it from the web of die-cut labels and re-winding it on matrix re-wind roller. Waste may also be removed by shredding into small pieces and/or by extraction systems that convey the waste away for bagging or baling. Also known as the waste skeleton.

Micro perforation – Very small perforations or minute pinholes in paper that enable a section or part of the paper to be easily separated. Micro perforation leaves a smooth edge without the normal more jagged edge found with standard methods of perforation.

Operating temperature – An operating temperature is the temperature at which a label press operates. The press will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the maximum operating temperature (or peak operating temperature.

Oxidation – result of a reaction between tool face and oxygen exposure. In order to prevent tooling to rust (oxidation) please clean and oil the tool carefully before storage. Oxidation can have a detrimental effect on the cutting results of both rotary dies and well as flexible dies.

Perforation – A line or row of cuts or tiny holes that enable a paper or web of labels to be folded, torn off or separated easily. Perforation may be horizontal or vertical with standard or micro perforations (cut versus tie).

Razor slitting – Mostly used for slitting thin plastic films – these type of systems are very simple, quickly and easy to set. Although razor blades are a low cost product, they need to be frequently changed to ensure a good quality slit edge.

Rotary Pressure (RP) cutting – a shear type of cut made by passing two precisely machined cutters by or through one another. The material is actually squeezed or compressed to the point of bursting without the two parts of the tool ever touching. The two cylinders that make up the tool set both rotate at exactly the speed in order to create a perfect match. Not very common in the narrow web industry. Only for cut through applications and (very) long runs.

Rule cutters – Rule cutter are used for flat die-cutting in presses where the web is momentarily halted during the actual cutting process. Consequently, the output speed is somewhat slower than when rotary tooling is used.

In its most simple form, the flat ruled cutter may be produced by working to dimensions, obviating the need for a drawing when the shape is a simple square, rectangle or circle. For more complex cutting shapes a key line can be drawn by hand or created by some form of electronic origination at the same time as the label design is created.

Shear cut – Used to describe the cutting of a continuous web of stock using an action similar to the action of scissors.

Shear slitting – Shear is the most versatile slitting method. Shear slitting can be used for a wide variety of papers, films, laminates and foils. Shear slitting variations can be ‘tangential/kiss’ or ‘wrap’ shear which involves a loaded male blade against a female ring, creating a scissoring effect to slit the web. Shear slitting typically provides the highest quality edge quality.

Sheeting – Converting rolls of printed or unprinted label-stock into individual sheets on a roll-fed press.

Slitter/re-winder – The use of slitter/re-winder technology is one of the principal methods of off-line converting rolls of self-adhesive labels, tapes and flexible packaging film into the correct width rolls ready for shipping to customers. The operation may also be combined with web inspection as part of the final stage in a converter’s quality control program.

Slitting – The action of cutting rolls of label stock to specified widths on a slitting machine. Slitting is undertaken using either stationery or rotary knives or blades in a machine with roll unwind and rewind devices, tension control and web tracking. Slitting of master rolls to narrow-web roll widths is normally undertaken by the label stock manufacturer, whose machinery has lubricated slitting knife cleaning pads on each rotary blade to stop adhesive build up on these slitting tools. These slitting machines also have a special splicing table, before the slitting station, where a diagonal butt splice can be made after removal of pre-marked sub-standard material, plus paper mill and coating machine joins.

Slitting wheels/knives – Dividing a web of label stock in the lengthwise direction by rotating slitting knives so as to produce two or more narrower webs. Slitting may be carried out with shear or crush cutting. Shear cutting produces a good quality edge a high line speeds with little dust; crush cutting can be economical if speed and edge quality are less critical.

Standard air eject dies (through shaft bore) – Air eject cylinder which uses compressed air to blow out of the holes drilled in the various cavities. For these types of cylinders there is little/no control over the waste ejection.

Stepped anvil – An anvil with the bearer area either higher or lower than the main body. Stepped up – bearer is lower than the body, creating a deeper cut.

Stepped down – body is lower than the bearer, creating a more shallow cut.

Stripping – Also called waste stripping. Removal of the face material and adhesive (the matrix waste) from around the die-cut label by taking it around a roller, or over a metal bar, prior to being re-wound. See also Matrix waste.

Thru cut/Through cut/Cut through – The action of die-cutting through all the layers in a pressure-sensitive laminate. This may take place in just one part of the cutter profile, or it may involve the complete profile.

Tolerance – the permissible deviation from a specified value. This applies e.g. to flexible die height, calliper of a backing.

Tool(ing) steel – Tool steel refers to a variety of carbon and alloy steels and that are particularly well-suited to be made into tools. Their suitability comes from their distinctive hardness, resistance to abrasion their ability to hold a cutting edge, and/or their resistance to deformation at elevated temperatures (red-hardness). Tool steel is generally used in a heat-treated state.

Trim – Trim is used to describe the normal edge waste that is removed from a master roll of label stock. On the printing and converting line, trim describes an action on the press, i.e. edge trim, waste trim.

Vacuum die – Rotary dies with removable inserts. Instead of blowing out the waste, the cut out particles are sucked away through the journals by means of vacuum.

Wear resistance – The ability of tooling steel to resist erosion. Wear resistance in tool steel is achieved by the presences of carbides. Chromium, molybdenum, tungsten and vanadium are the four carbide-forming elements commonly found in tool steels.

Web tension control – the amount of pull or tension applied to the web as it passed through the press. Poor tension control will result in registration problems in the printing, embellishing and converting processes.

Intro section

The aim of this series of articles has been to provide a good basic understanding of the use and production of the many different forms of die-cutting and tooling that a label converting plant will come across in their day-to-day business. However, there are many other words and terms used by various industry suppliers that converters may come across when reading technical articles or supplier literature.

It has therefore been decided to include a supplementary ‘Glossary of die-cutting and tooling terminology’ in the book so that readers and students can have a quick reference source to go to when they have a query. The Glossary is not meant to be fully comprehensive, but combined with the other articels in this series, should nevertheless cover the great majority of words and basic terms that they may come across on a regular or periodic basis.

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Optimizing the die-cutting process

Feedimporter — Thu, 12 Nov 2020 14:03:00 +0000

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Optimizing the die-cutting process

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Getting the most out of your finishing equipment

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