System architecture and operation
This is where the coins are embossed with the minting motifs (not part of the phil-vision solution)
The coins are placed on a tray by hand, then first the position and rotation are recorded by four high-resolution cameras in order to subsequently determine the colourable motif details on the coin relief from the measurement data (position and rotation) and extract the information relevant for printing.
A specially developed algorithm analyses the captured image data to identify the exact position and size of the motif details to be printed. This algorithm ensures accurate recognition even when the orientation of the coins on the tray varies.
The detected print information is transferred to the printer in real time to ensure the required accuracy.
The selected motif details are printed precisely onto the coin relief. The printing process is designed for highest accuracy and colour fidelity. In this application a Roland printer is used, software adaptations for other makes are possible at any time.
After the printing process, the coins are automatically packaged and prepared for delivery.
Intensive collaboration as the key to success
Extensive preparatory work and coordination was necessary for the system to function smoothly. We attribute the high acceptance of the pvPhotobox among users primarily to the fact that we involved the operating personnel in the development right from the start. Starting with the formulation of the requirements up to the details of operation and handling, all details were intensively discussed not only with the management but also with the users.
Theoretically, any number of printers can be connected to the system, however, a maximum of 8 makes sense. The limits here are only set by the time required for the manual loading of the trays. The required evaluation time is 2 seconds per coin, i.e. approx. 5 minutes are needed for a full tray with 250 coins.
Peter Steinbrück, responsible project manager at phil-vision, on the challenges of the project:
"Having worked with the Hamburg Mint on various projects in the past, I was already aware of potential problems and sources of error. In any case, we wanted to achieve the targeted printing accuracy of 50µm. For our customer, of course, this target referred to the finished product and not to our measurement results. Unfortunately, the printers used are far from being able to maintain this tolerance for an absolute dimension. The printers are too imprecise in absolute terms, but with very reproducible results, a fact we took advantage of to find an acceptable solution by including the printer tolerances in our calibration."
Guido Beckmann, Head of the Hamburg Mint, summarises the collaboration with phil-vison as follows:
"phil-vision took over the selection of the components and the programming for this project and supported us extensively during the integration. The cooperation was very professional and focused.
In every phase of the project, great emphasis was placed on precision and detail. The fast response times, the project management and the general high level of competence were also positive".
Hamburgische Münze (Hamburg Mint)
The Hamburg Mint is Germany’s oldest mint. Its history dates back to the 9th century. The first known Hamburg coin dates back to the year 834. Today, the Hamburg Mint is a legally dependent state enterprise of the Hanseatic City of Hamburg. It is supervised by the city's financial authorities. With around 40 employees, it is one of five mints in Germany that produce coins on behalf of the Federal Ministry of Finance to supply the population and trade.