Digital Ceramic Printing: A Logical Success
Why transitioning to digital technology was a natural evolution for the ceramic tile decoration industry – and why this transition may provide a future model for other industrial applications.
Our special "SWOT: Changes & Challenges" issue brings industry experts together to consider strengths, weaknesses, opportunities, and threats to screen printing. Our "Threats" section features expert Matthews-Paul, who examines the ceramic tile printing industry's rapid shift to digital technologies.
Where functional and industrial printing cross into decorative applications, many examples fit neatly into today’s remit for digital technology. One of the most challenging – yet successful – of these is the realm of ceramics. Functional printing is increasingly turning to inkjet’s capabilities, with some end products proving to be particularly effective, such as those where market trends and economic factors demand lower volumes, greater versatility, and better environmental practices that include lower levels of waste.
Traditions in Ceramic Printing
Today’s ceramic production represents something of a metamorphosis, returning to its roots of individuality away from mass manufacture and decoration of identical items. Aesthetically, the physical process of marking tiles has been evidenced in the context of art since 4000 BC; early examples come from Egypt and became associated with stylized products that ultimately relied on bulk production as new markets developed. Both decorative and functional, their tough glaze made them suitable for building products, sanitary ware, and wallcoverings, which were easy to keep clean and maintain.
Tiles are produced from clay minerals to which chemicals are added to enable shaping. Then, they are processed so that the raw materials can be tumbled and ground before being milled and pressed into the required size and thickness. But ceramics printing extends into areas that have traditionally required specialty inks and high-temperature firing processes to provide a durable finish onto a series of products, including crockery, where breakage must be avoided.
Until recently, the ceramics printing industry had strong roots in analog production technologies that looked unlikely to change with the advent of newer decoration methods. Tiles were generally unsophisticated, thanks to techniques that produced fairly basic results but fulfilled the requirement for high volumes at low costs. The key criteria were long runs and minimal prices; these offset time-consuming and expensive setup and preparation that were both essential to maintaining competitiveness across manufacturers.
The resulting printed products were designed to offer consistency and were restricted to plain tiles or those whose patterns could be repeated without variation. Using the screen-printing process, color consistency was almost impossible to replicate with any degree of accuracy across different batches but, with no feasible alternative, the world at large had no option other than to accept the limitations imposed by analog methods. Ceramic tiles and other items produced in the same way were ripe for conversion to digital printing.
Recession and Change
Behind this metamorphosis were several drivers that resulted in an “industrial revolution” for this particular segment. The worldwide economic downturn, particularly during and after the recession of 2008, was responsible for diminishing the demand for projects in which ceramic tiles traditionally played a part. With the building trade being affected adversely on a global scale, manufacturers found it increasingly difficult to maintain margins and stay profitable using conventional printing methods.
Digital inkjet printing had already become a standardized process in the graphic segments by the time the global recession took effect. And although initial developments were underway that were designed for functional and industrial decoration, most of these techniques were still in their infancy. However, in the ceramics market, it was evident that change was needed both in terms of production accountability and logistics, as well as from financial and environmental standpoints. This declining sector was affected significantly by the reluctance of the supply chain to continue to purchase and store products in very high volumes. At the same time, end customers were driven by fashion trends that increasingly required creativity and individuality. These parameters could not be achieved using analog production methods that were based on a high-volume, low-cost manufacturing model that required long lead times from design through production to delivery of the end product.
The composition of a screen-printed tile was based on a relatively thick and heavy base product that could accept the stress and pressure applied during its production processes. It also needed to be able to handle flatbed or rotary screen printing that could include several colors followed by glazing with a liquid coating and firing in a high-temperature kiln. This combination of techniques was subject to a variety of disadvantages including limited design options and restricted pattern variation, the time needed to change a job, the color consistency testing needed to make sure that the fired product matched the shades required at the outset, and accountability for post-production breakage.
With so many criteria restricting the potential creativity in ceramics production, it was hardly surprising that it swiftly became a strong contender for digital printing around the globe. Although China remains the primary producer, European countries such as Italy and Spain were gaining a strong reputation for generating more unusual and appealing designs. Although production costs were higher, the end results became increasingly popular throughout commercial and domestic market sectors. (It is worth noting that, through more localized manufacture, tidier logistics and faster deliveries also benefited the supply chain and end purchasers.)
In addition to shorter setup times, faster prepress, and the ability to generate lower volumes, there was also the obvious benefit of customization and variable-data printing. None of these features were available using traditional analog methods and, for these reasons alone, digital production was an inevitable choice for ceramics. Another advantage quickly became apparent. Because inkjet is a truly non-contact technique, the volatility and fragility of ceramic materials became easier to overcome. Lack of pressure on the substrate meant that thinner media could be printed than with screen. This not only lowered the unit cost, but also increased productivity as greater numbers of finished tiles could be shipped in a single container. The versatility of final applications was also enhanced with the availability of a finer and more sophisticated product.
Digital printing, as we are well aware in the graphics and display sectors, can be finely tuned to match precision colors and, while the shades traditionally used in tile production were not necessarily based on a CMYK palette, the need for effective workflow and color management has always been high. Using analog methods, matching between different batches of product has been unlikely, if not impossible. This, in turn, encouraged manufacturers to err on the side of caution and overproduce lines with the intention of being able to replace or add pieces to an existing installation without a noticeable color shift.
Despite the obvious benefits available to producers of ceramic products, this segment was relatively slow to commercialize. Although inkjet printing was well established within other areas, and its potential was under development for functional applications, early digital engines designed for this sector were not successful. The combination of components needed for manufacturing tiles and related items was not immediately obvious; key elements required absolute compatibility that covered the idiosyncrasies of working with the materials and finishes that are specific to this area.
Added to this, a new workflow needed to be developed that moved from a traditional design and prepress configuration to one driven by a digital front end. Being able to emulate typical ceramic styles involved a transition to a color model that wasn’t always familiar to conventional tile manufacturers. Ironically, the ability to match colors with software has not only enabled specialists to maintain their existing shades for accurate onward reference and production, but now also enables additional creativity to be integrated into print runs. Thus, in many ways, today’s tiles emulate those from the centuries in which each unit was different, either because it was hand-painted or decorated using a basic stencil.
By 2009, digital ceramics production was finally confirmed as being a truly viable, cost-effective, and workable proposition. During the previous two years, the ceramics industry was starting to realize that the rapidly changing market dynamic would make it essential to adopt shorter runs, reduced lead times, and just-in-time production to answer the growing reluctance of wholesalers and retailers to maintain aged stock levels. Additionally, ceramic production presents a golden opportunity for back-shoring. This type of model is already successful in the textile printing industry, and the same principles apply when low volumes and fast desktop-to-finished products are required to meet today’s market demand.
Adapting to Ceramics
Although the conversion to digital printing might have been slower than originally expected, especially with the added weight of the economic downturn, acceptance was remarkably fast once inkjet was able to prove itself. Certainly, for engine manufacturers and system integrators, it was a challenge to match all the requirements demanded by the ceramic segment without compromising quality, durability, and unit price. Specific criteria included the right type of colorant and its ability to maintain fidelity during the firing and glazing process. Additionally, the substrate surface could be irregular and even dusty, and this meant that the reliability of printhead nozzles was vital. In early machines, jetting problems were common as residue buildup and clogging necessitated frequent cleaning and maintenance procedures. Similarly, the obvious appeal of single-pass technology was, at the start, largely impractical because of performance compromises.
The key breakthrough lay in printhead development to enable even jetting regardless of surface condition or undesirable variances that occurred during the manufacture of the ceramic product. From a financial point of view, mass production of the base item did not lend itself to clean-room conditions and, thus, a solution had to be found that would not compromise digital’s advantages given the practical obstacles of the application. Ink viscosity also played a vital role; recirculation within the printheads proved essential to preventing nozzle blocking through excess sedimentation.
As a result, successful ceramic printers adopted the most suitable components that were developed by a variety of manufacturers who realized the importance of correct integration. Likewise, producers of ceramic inks finally tuned their chemistries to accommodate the specific requirements of printheads, nozzle performance, and substrate tolerances. The design of the print engine itself also needed to take into account the handling of relatively fragile materials, both at the in-feed and takeoff stations. Added into this equation was the need for minimal downtime during maintenance schedules combined with the ability for high-speed quality throughput.
As ceramic materials become thinner and, in many cases, larger thanks to their ability to be printed using a non-contact technique, so the demand for optimizing deposition has increased in complexity. The need to minimize breakage has also encouraged greater creativity in design and texture, which, in turn, has added aesthetic value, often turning a relatively dull and functional item into one that generates much higher margins for printing companies and their sales channels.
Manufacturers across the different sectors of digital printing contributed to the metamorphosis in ceramic production, enabling smaller countries to join in the established success of China by adding new technology. Given Spain’s traditional associations with this market, it is fitting that Spanish-based companies like Kerajet and EFI Cretaprint are extending tradition by ensuring inkjet capabilities are brought within the remit of manufacture. Another early entrant into the digital market was Durst, with contributions that have added to the versatility now available to established and new producers in this segment.
But the breakthrough came because printer manufacturers, ink developers, and printhead specialists worked together and pooled their expertise. They found a way to jet aggressive materials in a hostile production environment onto imperfect substrates using a unique, purpose-built workflow. As we contemplate screen’s future in industrial printing, tiles offer an intriguing model for how similar challenges may be overcome in other markets.
Logic and Fashion
In summary, conditions were ripe for digital printing in the ceramics area to gather momentum quickly. As a result, nearly 60 percent of today’s tiles are printed using inkjet engines and, even though China still produces the majority of them, it is notable that digital processes are appealing worldwide. Countries such as Brazil and India – formerly responsible for a large quantity of analog production – are also seeing significant conversion to digital alternatives. Europe, too, is attracting the manufacture of ceramics with clean processes complemented by reduced waste and the requirement for low stockholding, removing many of the space and logistical issues previously associated with this market.
Inkjet’s propensity to emulate grain, textures, and finishes has also been hugely beneficial, together with high-resolution images and the ability for every tile to contain a design variation. One of the cogent advantages where digital has no rival is the fact that, unlike graphics and most textiles, finished products are juxtaposed to form the finished application. Unusually, this is a segment where color consistency and production accuracy are linked with variable-data printing, thus requiring the best of all worlds so that repeatability can sit alongside customization. Ceramic production is also driven by trends in the same way as fashion and interior décor, and must be able to accommodate design changes and preferences within a short time period. Faced with so many economic, logistical, and design challenges, it is easy to see why this particular area of decorative industrial printing has provided a relatively straightforward and practical example of how a traditional analog production process can gain by moving to digital technology.
For more from our "SWOT: Changes & Challenges" special issue:
Screen Printing: A Technology at a Crossroads, Steve Duccilli
Why Industrial Applications Hold Tremendous Promise for Screen Printing, Mike Young
Screen Printing: King of Textiles, Charlie Taublieb
The Future of Functional Printing, Wim Zoomer
A Partial List of Industrial Applications for Screen Printing, Wim Zoomer
The Limitations of Screen Printing in the Graphic Arts, Tamas S. Frecska
Why Web-to-Print Software Matters for All Printing Businesses, Eileen Fritsch
A Sampling of Web-to-Print Software, Eileen Fritsch
Threats to Screen Printing, Inside and Out, Mark Coudray