Revolutionary print head technology for dimensional printing of 3D structures in ceramics with large particle glazes
Norbert von Aufschnaiter, Durst Phototechnik AG Brixen, Italy
The complete digitalization of the glazing lines has long been a wish of all tile manufacturers in order to make the entire production process more flexible and cost-effective. On the one hand the optimization and reduction of batches to optimize sales and storage with guaranteed repeatability, while on the other hand new possibilities for the development of innovative products in the tile sector with an unlimited number of structures in perfect match with the décor to imitate nature.
What is still missing is a technology for the digital printing of structures that are created in a fully synchronized way following the decors. This would allow the entire production process to be controlled digitally without exchanging or adjusting mechanical parts when changing products, regardless of batch size. A development that Durst has been working on and will soon digitalize this missing, traditional part of tile production.
The future True Digital Tile Manufacturing process includes the following essential digital production steps:
- Flexible, variable-size, variable-thickness slab and tile pressing equipment used in combination with a flat mold, full digital control and production of the desired tile size. This technology has already been in use for several years.
- Durst Gamma DG Single Pass Digital glaze printing system with patented Durst RockJET™ print heads for digital printing of variable structures on the tiles using ceramic glazes with particle sizes >45 micron and high viscosities. This is currently in the final stage of field test at two well-known Italian tile manufacturers.
- Durst Gamma XD Single Pass Digital Decor Printer with standard piezo print heads for printing the graphics with pigmented ceramic inks in perfect match and synchronized to the variable structures printed with Gamma DG. This allows manufacturers to create new innovative products with a naturalness not possible up with traditional production technologies. This can be especially important with wood or stone decors.
- True ceramic color management system Durst-ColorGATE CMS designed and optimized for the special conditions and requirements of the tile industry. This offering facilitates high flexibility, long-term repeatability, and a strong reduction of downtimes during product changes and the ongoing reprinting of the product collections over time.
- Durst Gamma DG Single Pass Digital Glaze Printing System for digital finishing by wet application of special materials for aesthetic and functional effects.
Current commercial piezo print heads are designed to handle inks with particle sizes below 1 micron, and some large drop print head can go as high as 2 microns while maintaining a reliable jetting behavior. However, jetting fluids with even larger particles (>3 microns) with the limitation to have those inks formulated with relatively low viscosities – required by such piezo print heads – becomes difficult to assure a reliable operation due to the sedimentation behavior with larger particle sizes.
Essentially, the current design of piezo print heads cannot be scaled up to work with large particle sizes in combination with the needed much higher viscosities to keep such “heavy” particles in suspension, and to hold up printed structures on the media.
Therefore, this part of the ceramic tile production process has still remained traditional due to the non-availability of a print head technology designed for jetting fluids with large particle sizes (> 45 microns) and high viscosities.
In order to digitize this large portion of the ceramic tile business, several years ago, after revolutionizing the ceramic tile decoration by introducing the first single pass digital printer, Gamma 60, Durst started a development project to develop and manufacture such a revolutionary print head for dimensional printing (digital structures) for water based ceramic glazes with large particle sizes (> 45 microns) and high viscosities not available before.
Innovative and seen as the next big revolution in ceramics Durst currently has two (2) installations of Gamma DG single pass printers with this print head technology in operation.
Digital Durst Structure Printing
Durst True Digital Glazing technology for printing ceramic glazes is seen as the next and even more important revolution in the tile sector after digital decoration.
At the heart of this innovative production process is the RockJET™ print head technology developed and built by Durst specifically for Durst Gamma DG. The Durst Gamma DG is the first high performance single-pass printer for digital glazing/printing of structures on flat ceramic tiles instead of creating the very limited and repetitive structures that do not follow the decoration by means of press molds.
Thanks to the water-based ceramic glazes with large particles (> 45 microns), high viscosity, and application rates of up to 1kg/m2 it is possible to produce even very strongly emphasized structures. This revolutionary technology with a very high resolution and richness of detail, proving high reliability and production flexibility in industrial applications, is very impressive.
Gamma DG has a modular design and can be configured in width and number of glaze printing series according to customer requirements with the possibility of being further expanded later.
To create structures digitally and precisely in perfect match with the décor is a long-cherished wish of the tile manufacturers. This technology allows one to imitate wood, stones, and marble to be even more lifelike, and thus to achieve a decisive added value in the products and to develop and produce new, unique and so far not possible, innovative designs with visually captivating and tactile effects. In addition to the impressive print quality, the tiles can also be printed simultaneously with two different glazes, for example matt and glossy.
Digital structure printing with Durst Gamma DG also brings important advantages in the development and industrialization phase of new products. It is now possible to test several different structures on a single tile without both additional costs (production of different mechanical molds) and also retooling.
Advantages of digital structure printing with Durst True Digital Glazing Technology:
- Development of innovative, unique products with very natural effects thanks to the digitally created non-repeating structures in perfect match with the décor (design).
- High production flexibility, especially with small batch sizes and frequent product changes, which can be automated and optimized in terms of time and costs.
- New optical and haptic effects, which emphasize the advantages and naturalness of the ceramic tile even more than other materials. This makes it visually and tactile difficult to distinguish from natural products, while also having properties that are superior.
- Highest production efficiency, as a basis for future on-demand tile production