DEMCON distinguishes itself through the careful approach of complete development processes, from concept to end result. However, this does not mean that an assignment is per definition subject to a long lead time. If required, DEMCON can carry out a development project under demanding time constraints with the utmost care. An exceptional example is the project for ‘de Koninklijke Nederlandse Munt’, which had to lead within one month to a working quality control system – to be delivered in Chile.
The client was faced with quality problems that had occurred during the transportation of a large consignment of coins. Some coins appeared to show signs of corrosion or other stains and had to be removed from the consignment. Failure to deliver the consignment timely and without flaw would have resulted in a fine. Manually checking and sorting of the coins proved to be an unworkable solution, which led to ‘de Koninklijke Nederlandse Munt’ calling upon the help of DEMCON. The request was to develop and build a machine for high-speed automatic surface inspection of coins and install it near the end customer in Chile within a month.
DEMCON immediately spoke to ‘de Koninklijke Nederlandse Munt’ and at the same time dove into the lab to carry out the first tests on the coins. The result was that DEMCON could possibly resolve the problem. After the client had given his approval, a project team was immediately formed, which also involved sister company DEMCON Focal. Existing coin inspection machines pay particular attention to the quality of the engravings on the coin, thus a new design was needed. Due to time constraints, reuse was considered an option and the concept that was chosen was determined mainly on the basis of quick and simple tests. An important aspect was the immediate availability of components.
The greatest technical challenge was the complex, model-based vision algorithm, which had to detect in near real time a large variety of stains and make a decision with 100% accuracy – approve or reject. DEMCON substantiated that with a thorough statistical analysis. It was essential to ‘teach’ the algorithm on the spot by inspecting batches containing coins with specific quality problems. In this way, unexpected problems could be intercepted immediately.
During the design, a great deal of emphasis lay on the performance of the machine with a view to a reliable operation in Chile under unprecedented circumstances. A robust compressor unit was specially built for the required pneumatics and a stable power supply was a point of attention. The machine was subsequently built within a very short time and subsystems were tested in parallel. Following the successful acceptance of the machine, it was ready for transport to Chile within four weeks.
In cooperation with people from ‘de Koninklijke Nederlandse Munt’, employees of DEMCON took care of the installation and teaching of the vision algorithm. The flawless functioning of the software and hardware was closely monitored from the home base in Enschede, where continuous contact with the operators on site was maintained. Ultimately, the machine continued to run at full capacity for over three months in Chile and inspected 40 million coins. The result was successful because the end client approved the inspection without a hitch.
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