Next level 3D engraving
World records are always a special thing. Especially if you have been actively involved. The Croatian Mint / Hrvatska kovnica novca holds the current Guinness World Record for the smallest gold coin in the world. Find out how the motif was realized on the minting die and what role a femtosecond laser and patented ACSYS technology played in the process in the following success story.
Small, smaller, smallest
The smallest gold coin in the world
Gold coins have been around for over 2500 years. And over the centuries, their production has become increasingly sophisticated and detailed. As the market leader for laser systems in the Mint & Print sector, we support renowned mints from all over the world. Many exciting projects have emerged from this collaboration. However, we have only been able to help set a world record once before. The Croatian mint Hrvatska kovnica novca planned a world record for the smallest gold coin in the world for a collector’s coin. Switzerland’s Swissmint secured this title in 2020 with the one-quarter franc gold coin with a diameter of 2.96 millimetres and a weight of 0.063 grams. The motif, Albert Einstein sticking out his tongue, was not recognizable to the naked eye. The Croatian Mint’s goal: even smaller, even more detailed.
Filigree 2mm punching tool
The theme of the world’s smallest gold coin is also in keeping with the world record: it is dedicated to the smallest city in the world, Hum. Despite having only around two dozen inhabitants, Hum can call itself a town for historical reasons and is now a popular tourist destination with many well-preserved buildings, a town wall and a rich history. And this is exactly what the 1 kuna coin tells us about. It is the last kuna coin to be minted in Croatia, as the Hrvatska kovnica novca is saying goodbye to the kuna with this special edition.
With the last Kuna coin, the Croatian mint proves its skills: the new Guinness World Record for the smallest gold coin in the world goes to Croatia with a weight of only ~0.05g and a diameter of just 1.99mm. An ACSYS PIRANHA® µ femto laser system was used to produce the 2mm small punching tool with all its fine details. The 3D engraving of the motif was carried out directly on the minting die. Direct laser engraving offers the advantage that it shortens the process of producing an embossing tool many times over. Whereas it used to take days and weeks to produce a new minting die, the process now takes just a few hours. This is of course an enormous factor, especially in the production of such a delicate and innovative coin – particularly from an economic point of view. With a print run of just 199 copies, cost-effectiveness in design and production is an important factor.
Engraving and polishing in one step
And the Femto-class Ultra Short Pulse Laser (USPL) installed in the PIRANHA® µ has yet another advantage: in addition to the impressive precision and speed of engraving, the surface of the coin is made clean, smooth and shiny with the help of the patented Pulse Forging® technology, similar to polishing. And the ultra-short laser pulses ensure that neither the material properties nor the hardness of the tool are changed.
Counterfeit protection is paramount when minting coins with Direct Laser Engraving. ACSYS laser systems enable highly forgery-proof direct hallmarking on coins and in the watch and jewelry sector through specific parameterization. Individually adjustable beam profiles ensure uniqueness and provide a perfect basis for verifying authenticity. This method is particularly suitable for delicate objects, such as the world’s smallest gold coin with a diameter of less than 2 mm. Conventional hallmarking would damage such a delicate coin or the stamping process would cause distortion.
ACSYS laser systems with µ functionality are able to engrave the finest contours and 3D structures in a stamp. The LAS – Live Adjust System HD dual camera preview offers the unique opportunity to create the hallmarking pattern on the monitor directly on the stamp blank. Thanks to special functions in the AC-LASER software, minting dies can be created highly efficiently – from file creation to output on the laser, everything is perfectly coordinated and offers the user an intuitive workflow. And direct laser engraving eliminates the need for subsequent finishing.
Conclusion
With ACSYS Ultra Short Pulse Lasers, processes such as Direct Laser Engraving and Pulse Forging can be used specifically for the production of high-quality minting dies. The perfect coordination of software, hardware and processes is a decisive advantage for mints from all over the world and a real USP of ACSYS Lasertechnik. Because world records can only be achieved with top performance at all levels.
Your ACSYS expert for Mint & Print
How can I help?
Let’s get in touch.
Alexander Aminidis
Head of Global Business Unit Mint & Print
Telephone: +49 7154 80875 33
E-Mail: a.aminidis@acsys.de