Flexible Printing Processes for Flexible Packaging

Customized packaging, the dovetailing of packaging with digitally enhanced capabilities, and finished packaging are currently dynamizing the industry. To deal more efficiently with these changing market and customer needs, new printing processes such as digital printing can provide support.

In the crisis-ridden printing industry, packaging printing is still one of the few stable sectors, because regardless of product quality, the need for packaging is a guarantee in all industries. However, the times are also changing in the packaging industry, as shown by various trend analyses, including one by Bobst Group SA, an internationally active Swiss manufacturer of machines and systems for the packaging industry, because no one can afford to recognize packaging trends too late. Digital printing, the experts agree, should now be able to accompany this upheaval better than conventional printing processes. So it’s worth taking a look at what digital printing can do for packaging.

The three major trends currently evident in the packaging industry include, firstly, increasing demand for short runs as product cycles become shorter and product portfolios become wider. This is because product manufacturers, especially those targeting a younger clientele, are increasingly addressing individual buyer groups via ever more customized labels and cartons. Coca-Cola, for example, is one of the pioneers in this field with its Light and Zero products. There are now a large number of variants. And each of these products is offered in packaging of different shapes and sizes: in PET bottles, glass bottles or cans. Diversification is increasingly being recognized as a success factor, and Coca-Cola is just one example among many.

Trend number two is digitalization. New digital technologies offer print service providers a broader field of possibilities, such as augmented reality (AR): the dovetailing of printed packaging with digital content such as videos or animations that can be accessed via an AR app extends the length of time a potential buyer engages with a product. In addition to increasing the incentive to buy, it also opens up the possibility of conducting advertising campaigns in an interesting and measurable way.

A third growth factor is the area of finishing and further processing. For example, gilding or embossing is currently frequently required for labels and packaging – not only for perfumes, chocolates, or luxury goods, but also for wines and beers, for example. Holograms and invisible markings offer visually inconspicuous protection against product counterfeiting, for example in the pharmaceutical and tobacco industries. It is also conceivable that in the near future printed RFID antennas in metallic colors will boost interaction with customers – more effectively and aesthetically than the QR codes currently in use. Digitally enhanced packaging or labels that have been otherwise upgraded in addition to 4c printing have been shown to stimulate consumer purchase. The Foil and Specialty Effects Association, for example, found in a study that the time taken to identify refined products is 45 percent shorter than for products that have not been refined.

Three major trends, then, that are currently causing unrest in the packaging industry and are, at the same time, awakening desires to get a good slice of this pie, too. According to analyses by the market research company Keypoint Intelligence, global sales of digital color labels and packaging printing are expected to rise to almost 800 million US dollars in 2021. This corresponds to an increase of more than 65 percent since 2016.

Mastering the balancing act with digital printing

The possibilities offered by digital printing can now help to master this balancing act between market trends and the economically viable options for implementation, because it can be used to print series starting from one piece and on a wide variety of materials: paper, plastic, stone, glass, wood, metal and much more. The term digital printing is not a process in its own right, but a generic term for various printing processes without a fixed print body, because the artwork exists only digitally – It is created by computer and transferred directly to the material to be printed by means of a printer. The most commonly used digital printing processes for packaging are currently laser printing, inkjet printing, thermal transfer and 3D printing.

Advantages, disadvantages, and areas of application of the processes

Laser printing – with the subtypes latex printing, solvent printing, and UV direct printing – scores with high print quality (especially for lettering and graphics), low ongoing printing costs, low environmental impact, reliability, and long service life, and is also water- and smudge-resistant.

Disadvantages of laser printers are often the lack of depth and color fastness. While laser printer printouts are smudge-proof, they are not necessarily immune to flaking. Other disadvantages of laser printers include thermal stress on the print media during fusing. It is not possible to process electrically (partially) conductive media or completely rigid originals. Examples of applications include the serialization of pharmaceutical packaging: both laser and thermal ink jet (TIJ) printing can deliver high-resolution codes, which is required for the detailed representation of symbols and multi-line printing.

 

Unlike laser printing, inkjet printing involves spraying tiny colored drops of ink onto paper or textiles. The advantages of this printing method include high speed and print quality, low purchase costs, low energy consumption even during printing, and reasonable follow-up costs if the consumables are chosen wisely. The disadvantages include the printer cartridges: they can often dry out easily or smudge quickly when touched. Nevertheless, inkjet printers are also increasingly finding a place in the packaging industry, for example for primary as well as secondary packaging, because they not only mark at high resolution, but also at top speed and are therefore also used for serialization printing in the pharmaceutical industry, for example, in addition to shelf life and batch labeling.

Thermal transfer is the term used for indirect printing processes in which the print is transferred from a transfer layer to the printing stock by means of heat treatment. This process is suitable for motifs with only up to three colors, such as logos, pictograms, and lettering or similar uses. Advantages: because they work with heat, the devices do not require extra ink – there is no need to reorder and change toner and ink ribbons. They also require little maintenance and have a long service life. Among the disadvantages, the main one is the need for special thermal paper and the printing is sensitive to temperature and light. With thermal transfer direct printing or „thermal transfer overprinting“ (TTO), packaging films and glossy cartons are printed directly – without an additional label. This makes them particularly cost-effective. They can be used to apply labels such as best-before dates, batch numbers or ingredients.

The latest and probably most eagerly anticipated process is three-dimensional printing, or 3D printing. An important step in the development of packaging regarding this is the production of 3D models. Also called additive manufacturing, 3D printing makes it possible to create prototypes in a short amount of time – bringing to life an idea worked out on a computer. In-house 3D printers then build a three-dimensional 1:1 model of the design from CAD data within a few hours. This can be used to construct almost any type of packaging – already done, for example, with Bullrich salt, a pharmaceutical product that is offered in tablet form and as a powder. Here, for example, the specialists from Pöppelmann in Lohne have modernized the original packaging familiar to users and made it more functional. The outer contours of the plastic dispenser have been rounded off for a pleasant feel. A new hinged lid with tamper-evident closure facilitates dispensing. The highlight of the packaging is a pre-assembled, resealable bottom compartment for a take-along tube that complements the tablet bulk pack. Everything was produced using 3D printing technology. In particular, elaborate and unusual solutions,  thusly benefit greatly from the possibility of additive prototyping during development work.

by Dunja Koelwel