A Walkthrough of Digitally Printed Flooring

Unlike traditional staining processes, no special ventilation is required as the digital staining process does not emit significant volumes of volatile organic compounds.

In the printing industry at large, there have been several waves of analog-to-digital transformations in various stages of completion, from commercial printing to display graphics and textiles. For ceramic tiles, the transformation is virtually complete.

Why is this relevant to producing flooring? Some flooring, obviously, is created from ceramic tiles. But wood, wood laminates, and other materials also play a significant role. The decoration of these flooring materials is just on the beginning edge of the analog-to-digital transformation, and there is opportunity to convert this longtime analog market to efficient, high-quality digital printing.

Conventional Wood Decoration

Unlike UV-curable inks, mineral inks enable consistent tonalities in the final product while respecting the “soul of the wood” and displaying its natural imperfections.

First, it’s worth taking a look at how flooring is typically created today, with a focus on wood flooring. One method for wood flooring is to prepare the boards and stain them. This sounds fairly straightforward, but wood is a natural material, and its color and patterns can be inconsistent from one board to another. This requires manufacturers to stock a wide variety of dyes, and to undergo a great deal of trial-and-error testing to get to the desired constancy with the tonality of colors. This takes time and material, and can create substantial waste. In addition, manufacturers end up with a large inventory of remaining dyes that can be difficult to use in future projects.

Another means is to use a lower grade of wood and laminate it with gravure-printed material that simulates woodgrain. This process takes less trial and error, but requires laser engraving of printing cylinders, long makeready times, and significant waste. In addition, it is only viable for very long runs. This process is not only used for flooring, but also for furniture and other wood products. The substrate is printed and then laminated to the boards to prepare them for manufacturing into the desired end product.

Why Digital?

As with everything digital, the up-front process of creating designs — whether they are special stains, different wood grains, or other types of decoration for flooring — is fast and easy.

There are a number of reasons why manufacturers and their brand customers would be looking to increase digitization of the wood-decorating process — for the same reasons other disciplines within the larger printing business have undergone or are undergoing the digital transformation. These include consumer demand for more customization, the need to produce shorter runs of product to accommodate that demand, and a desire to achieve faster time to market at a competitive cost with lower inventory risk.

This is where digital printing shines. Some manufacturers are using digitally applied UV-curable inks as a replacement for traditional wood decoration technologies. While this can be effective for some applications, this would not seem appropriate for noble hardwood and veneers, as UV-curable inks are applied in a layer that sits on top of the wood.

There is an opportunity for the market to take a different approach with digital staining. Products such as mineral ink printers deliver a product more in line with conventional wood decoration processes. Inorganic pigment mineral inks behave in much the same way as conventional stains, being absorbed into the wood and becoming part of the wood. Boards are dry and ready for the next step once they exit the printer.

Not only is this process much faster than traditional methods of wood dyeing, but it has other benefits as well — benefits that will accelerate the analog-to-digital transformation in the wood flooring industry in much the same way it has happened with ceramic tile.

With the digital printing technology’s digital front-end (DFE), files for printing on wood are created digitally. When these are sent to the DFE, the first thing that happens after the files are processed is that it uses the on-board spectrophotometer — if one is embedded — to acquire a reading of the color of the specific boards to be decorated. From that basis, and based on the design, the DFE determines the appropriate amount of each ink to be applied to the boards to achieve the desired hue. This process ensures consistent and accurate coloration regardless of the hue or tonality of the base board.

With digital print and mineral inks, together with advanced color management capabilities, manufacturers are able to unify all tonalities.

This process can also be used to both simplify the wood decoration process and, in some cases, transform the look of the wood (for example, transforming birch to oak). The key factor here is that when in production and decorating natural wood, conventional processes often end up with different tonalities. But with digital print and mineral inks, together with advanced color management capabilities, manufacturers are able to unify all tonalities. This not only simplifies the manufacturing process, but it delivers the added value that all of the finished product is A-grade.

The introduction of high-quality mineral ink digital printing for wood flooring follows another flooring market — ceramic tile — that has already been transformed by the analog-to-digital transformation. With the proliferation of robust, high-quality single-pass inkjet machines for ceramics, the vast majority of decorated flooring tiles manufactured today are printed with inkjet as opposed to using analog methods. The inkjet tile printing process, where a printer images onto a slab placed in-line with a kiln, requires robust, reliable print solutions capable of performing in less-than-ideal industrial environments.

Now, the tile market is on the verge of another important evolution toward greater sustainability with the migration from solvent to water-based inkjet inks — an evolution made possible with the introduction of new “hybrid” print technology capable of switching from solvent to water-based. As tile manufacturers switch to water-based inks on hybrid printers, they can reduce up to 90% of volatile organic compound (VOC) emissions, and up to 73% of carbon emissions using a process that requires less drying time and delivers higher print quality compared with solvent tile inks.

The fact that digital has become such a success in tile speaks to the potential for growth in wood flooring, a market that has had more limited options in terms of volume and imaging capability for direct-to-board digital inkjet staining. And, as with tiles, digital printing for wood flooring creates some substantial sustainability improvements.

The Future of Wood Flooring

Though it is the very early stages of wood decoration using digital print, there are already success stories in the market that demonstrate how this technology will revolutionize the wood flooring industry. Though Kember Flooring, a large Canadian wood flooring manufacturer is currently in the prototyping stage before they go commercial with the process, it fully expects to be able to convert 100% of its wood flooring manufacturing. Digital print technology is also being utilized in the U.S. and in China, where it is being employed to produce panels in in one of China’s largest furniture factories.

These early installations are demonstrating how bringing digital printing to the vast majority of wood flooring, as happened with ceramic tiles, is not a pipe dream for the far future. It is here today, and companies are already benefiting from the technology. And there are many manufacturers taking an interest in how to either manufacture or source this type of unique application to meet future demand trends.

As with everything digital, the up-front process of creating designs — whether they are special stains, different wood grains, or other types of decoration for flooring — is fast and easy. Once designs have been developed, the manufacturing process is also faster, accelerating time to market and getting product on shelves faster, improving cash flow, and reducing inventory risk, since product can be manufactured just in time, or even on demand, depending on the requirements of the customer. How much faster? With analog production, about five to 10 linear meters per minute can be produced, whereas single-pass digital technology today is capable of staining wood planks at speeds of up to 60 linear meters per minute.

Digital stain with mineral inks makes it easy to obtain great tonal range.

Digital stain with mineral inks makes it easy to obtain great tonal range.

Digital stain with mineral inks makes it easy to obtain great tonal range.

And the beauty of the process, especially as opposed to laminated products, is that it “respects the soul of the wood.” Unlike UV-curable inks, which hide the beauty of the wood, printing with unique mineral inks enable consistent tonalities in the final product, but still display the natural imperfections of wood.

Digital wood flooring with mineral inks is also a greener process. It is recommended to create an enclosed, air-conditioned space with positive air pressure within the shop to cut down on potential contamination of the printheads with dust. But, unlike traditional staining processes, no special ventilation is required as the digital staining process does not emit significant volumes of VOCs. There are no solvents used in the new, water-based mineral inks introduced for digital wood staining. And, they are also compatible with standard primers and coatings already used in the flooring industry. The goal with an integrated digital solution is to be able to introduce this process into existing factories without having to change the surrounding processes.

Respecting the soul of the wood, enabling a wider variety of patterns, colors, and grains that can be applied to it is just one benefit of modern decoration of wood flooring. Digital technologies enable cost-effective production of smaller batches of product, reducing inventory risk and enabling more customization, while allowing for a faster time to market and decorating wood in a more environmentally friendly fashion, with less waste and no VOCs. Given the remarkable strengths coming to market with the latest technologies, it should be no surprise to see something similar in wood flooring as has occurred in tile flooring. As far as emerging industrial applications go, there is every reason to expect to see an analog-to-digital transformation occur in the flooring industry within the next five years. Print professionals with the expertise and command of digital manufacturing have a leg up in spurring this transformation. n

This article originally appeared in the PRINTING United Alliance Journal.