The CeraCode® marking solution created by the technology start-up Senodis Technologies GmbH enables clear component identification and traceability in high-temperature processes due to a newly developed ink which is heat-resistant up to 1,300 degrees Celsius.
Digitization is no longer a new territory in metalworking. Large amounts of data are already collected and evaluated in highly automated processes, followed by process and quality optimizations based on these evaluated data. However, at the moment these part-specific data cannot be fully read out or assigned. This circumstance creates many problems: sorting effort and costs in the event of errors, entire batches that have to be scrapted, correspondingly high scrap costs and overall quality defects in the supply chains. Impeding the individual marking of parts and components are the harsh production conditions under which metal components are produced. Conventional markings, in example laser engravings or prints with conventional inks, do not create markings in a sufficient quality.
Punching tools are often used in press hardening, but this marking solution only embosses week numbers and thus also do not enable individual traceability. In addition, the stamps often break out and require therefore a lot of maintenance. It is also possible that the sheet metal is affected negatively by the impact of the embossing.
Material safety is a key aspect in case hardening. The choice of material is very complex and, depending on the component, different quality factors are already assigned to the component at the start of the production process. Since the basic material can no longer be determined after the production process, mix-ups can easily occur without individual labeling.
Up to now, another option for marking the component can only be applied by laser engraving after the temperature treatment. However, this creates massive gaps in the component tracking through the production process as entire process steps are not tracked. On the other hand, this overall view, considering all relevant process data, is very much needed in order to achieve full transparency of the entire value chain. Based on this overall view, manufacturing processes can be improved, the saving of resources can be focused and internal as well as external logistics chains can be streamlined. Basically, only consistent data acquisition, collecting all data long the value chain, enables true digitization of the production focusing on quality assurance and process optimization.
Data matrix code printed with heat-resitant ink up to 1,300 °C
Senodis, a German technology start-up, engages in individual component identification and developed the CeraCode® technology, which prints a data matrix code on the components with temperature-stable ink. The ink developed by Senodis consists of ceramic pigments, creates an irreversible bonding with the component surface under the influence of temperature. In addition to steel, ceramic or glass are possible fields of application. Depending on the composition, the ink easily withstands temperatures of over 1,300 degrees Celsius and is due to this heat-resistance fully suitable for furthers production process steps such as press hardening or case hardening. During the development phase, the ink formulations had to be precisely matched to the condition of the component surfaces. For example, the adhesive pigments have to interact with the widespread anti-scaling layer used on aluminum-silicon alloys, but also be suitable for uncoated sheet metal. Basically, the ink is always selected for the customer-specific project and adjusted if necessary. For an optimal contrast when reading out the data matrix code later, inorganic phosphors and pigments are used instead of color pigments, which on the one hand withstand very high temperatures and on the other hand have an excellent fluorescence under certain lighting and are therefore easier to read. Important parameters for a precise and clear print impression are the viscosity and the surface tension of the ink in relation to the base material. It was necessary to ensure that the drops do not stick to the metal nozzle plate of the printers but do stick to the metal surface of the component.
In the cold state, the adhesion mechanism between pigments and substrate is based on organic binders, which already ensure that necessary process steps such as robotic gripping or stacking do not lead to smearing. The subsequent heat treatment activates the inorganic bonding agents that create the connection with the metal surface. The temperature sinters the inorganic materials, resulting in a marking which is permanent and could only be removed destructively. Even after the components have been painted later, special optical methods can be used to read the data matrix code through the paint.
Senodis has built up an extensive ink portfolio from which the right ink is selected depending on the component, material and surface finish. The inks are also adjusted to specific requirements if necessary.
Linking all relevant process data to the component
The component is clearly marked – but what information can be linked to it? Björn-Erik Mai, co-founder and managing director at Senodis explains: “Our customers often assume that only certain information can be linked to the component at the time of printing the marking and that later process parameters can no longer be added. That’s wrong. In fact, only an individual number is linked with the code, which is stored in a database. All process data relating to this component can then be assigned to this component in the database (production date, number, furnace temperature, throughput times, degree and strength of forming, material batch sizes, laser parameters, etc.).”
Marking in less than two seconds
The most important factor in closely synchronized production lines is the time factor. Thus, a marking system is not supposed to be a time waster. The CeraCode® marking shows its advantages in terms of time, in example compared to a laser station. The CeraCode® marking can be applied completely inline or in a maximum of one to two seconds, while with a laser engraving approximately one second per character to be lasered must be expected.
Considering multi-digit code numbers, the laser marking quickly takes five up to ten seconds, which is an impossible expenditure of time before the temperature and forming process steps. In addition, a laser engraving station is significantly more expensive and requires higher health and safety protective measures. Furthermore, the CeraCode® marking system can be implemented quickly and easily within a normal maintenance shift, both electrically and mechanically as wells as IT-related.
Senodis offers a one-solution-system consisting of an ink portfolio, industrial printer, image recording and IT integration. The basic version includes the labeling, the first recording and the second recording, taking place in front of and after the furnace. For reading out the markings industrial scanner are used. Björn-Erik Mai points out: “CeraCode® is a customized marking solution. We always adapt the system to customers’ requirements, in example adapting the ink to the specific surface properties or providing a database solution for the management of process data.” CeraCode® has already been installed and tested at a large German automobile manufacturer in a pilot project lasting several months.
Complete process digitization based on individual part tracking
From Senodis’ point of view, an end-to-end digitization is only possible if all relevant processes data in the production of a component are collected and considered. Björk-Erik Mai says: “Still using punching tools for labeling parts in press hardening is a outdated and represents a road block for end-to-end digitization. Only if you collect data live for each component, you can notice during the ongoing process if more pressing force is required because the press is moving due to wearing down. A check on a weekly basis reveals far too late that perhaps half of the components, which were produced, were not adequately formed. With our technology, live control and thus also live optimization is possible – via the digital fingerprint that we assign to each component.”