Keracromia®, optimising digital production

Digital technology is becoming increasingly important for the Italian ceramic industry. I intentionally use the word "technology" rather than "printing" because all too often excessive importance is attached to the printer, neglecting or underestimating the steps from the creative concept through to the physical operation.

In the same way, techniques tend to be transferred directly from different sectors without taking account of the specific nature of ceramic production, and the same tools and methods used as those adopted in the traditional screen printing process.

The Keracromia^® system is different in that it adopts a completely digital and objective approach based on the characteristics of ceramic tile production. On the one hand it provides colour management tools, procedures and methods and on the other tools for analysis and control of the digital printing process with the aim of keeping ceramic products at the forefront of aesthetic and technical research while making them financially competitive.

The system is independent of raw materials and machinery producers and of graphic design firms. It adapts to any technology chosen by ceramic companies, and it supports all printers and ceramic inkjet inks.

Thanks to the flexibility of the system, Keracromia^® adapts readily to the production requirements of ceramic companies of all sizes, from small and medium-sized firms through to multinational groups with widely different organisations and production and commercial strategies.

The results

The key to ceramic tile production is to combine perceived quality with a short time to market and low costs. This can be achieved through:

• Optimised time from idea to product
• Consistent results and reduction in defects
• Optimal plant utilisation
• Reduction in raw materials usage.

Cost optimisation: inks

Costs may either be directly measurable or they may be hidden behind generalised inefficiencies in the various design and production areas.

Inks belong to the first, directly measurable, category and account for a significant percentage of product costs. However, they can be optimised by using digital colorimetric techniques. It is a well-known fact that increasing the number of basic colours also increases the number of possible combinations for obtaining a given colour. As Keracromia^® is able to handle a virtually unlimited number of different colours, it allows the user to choose the ideal combination. A significant example is that of an Italian ceramic company that has achieved an overall saving in ink costs of more than 50% by switching from 4 colour bar printers to the current 8 colour bar printers.

Unfortunately, however, due to limitations in the tools used, short-sighted economic assessments or limited knowledge of digital techniques, companies often use just three colours even on machines that have a larger number available.

By automatically choosing the best combination, it is possible to change colours and/or supplier according to cost effectiveness without having to manually transform graphic designs - an operation that is both costly and brings uncertain results.

Improvement in quality

Improving quality is another way of optimising costs, both by reducing rejects and keeping tone stable, thereby reducing stocks. Keracromia^® also provides the tools necessary for checking print quality and consistency, independently of the supplier and the configuration of the physical device. In particular these include head and bar alignment and ink deposition linearity.

Better use of plants

This is an essential aspect although it is harder to measure. It concerns both the pre-production stage, in other words the process from the idea through to digital tooling, and aspects directly relating to production. During set-up, Keracromia^® drastically cuts times and costs, replacing the physical performance of test runs and visual checks with virtual verification directly on the PC. This means that optimum results can be achieved for a given product in a specific process at the first attempt. During the production stage, the Keracromia^® virtual verification performed in parallel by numerous process models allows the best production line for a specific batch to be chosen rapidly.

The Keracromia^® tools

The Keracromia^® tools are entirely digital and based on objective, universal quantities. They do not use calibrated monitors, light boxes or visual comparisons and the operator does not have to make even a single decision based on subjective judgement.

Keracromia^® uses various versions of spectral scanners (for tiles, stone, wood and other materials) with dimensions of up to 900x1600 mm and thicknesses of up to 70 mm, motor-driven on all three axes and with resolutions of up to 720 dots per millimetre.

Instead of targets designed for paper printing, the system uses specific palettes with thousands of colour combinations based on the printer characteristics (number of bars, deposition capacity, etc.).

The palettes are physically created by the production process that is being modelled, acquired using the spectral scanner and processed using the modelling module which creates a mathematical model of the specific production process.

The separation module then associates the target graphic file with the process model (or with a number of alternative models at the same time) to create a virtual prototype and thereby provide a numerical evaluation of the difference between the intended product and the actual results and determine the best available process.

The graphic file may already exist, it may be downloaded from the internet or it may have to be acquired. In this latter case the recommended solution is a spectral scanner, although the system is flexible enough to allow for the use of other non-spectral sources such as an RGB scanner, digital camera backs or other solutions.

The results of processing are shown in the figures below, the original image and the follow virtual prototype. After establishing an error threshold, in this case more than 92% of the surface is printable, while the areas that the process is unable to reproduce are highlighted.

The control panel enables the operator to change the acceptable error and to hide or display the dissimilar areas. Obviously, the larger the permitted error, the smaller the dissimilar areas.

If the result is acceptable, the tooling process can proceed. The alternative is to lower the threshold or choose a different production process capable of generating a wider set of colours.

These operations can be performed quickly and without costs using Keracromia^® virtual verification rather than physical prototypes.

If alterations need to be made to the graphics, Keracromia^® provides the operator with the information needed to make rapid and effective changes, then proceeds to the next virtual check.

The characteristics and operation of Keracromia^® can be verified at KeraLab, the laboratory set up by Macs Tech and Officine SMAC in Fiorano Modenese.