News from the world of minting technology – Part 2

by Ursula Kampmann
translated by Annika Backe

February 18, 2016 – There are a few set dates in the calendar of the coin technicians: One of the most important ones, established in the last few years, is the Technical Forum which, organized by Dieter Merkle / Schuler Presses and Thomas Hogenkamp / Spaleck, is held every year, Thursday before the opening of the World Money Fair.

The summaries of the first six presentations can be found here.

Robert Newman und Timothy Buck / Artcam: Digital Sculpting

They have become something of an integral part of the Technical Forum: the representatives of Artcam, presenting their latest tools. Developed by Artcam, a computer program transfers the old art of engraving to the modern world.
As their most important message, they stressed that the program has become faster than ever.
Additionally, of course, they came up with some nice new features. For example, in the process of designing, figures can be equipped with “bones”, rendering their movements quite naturalistic. This was illustrated by a starfish – which lacks any bones in real life – which, when animated by a computer, was dancing Gangnam-style in a way that appeared perfectly lifelike. 

The Phoenix Ascendant. Photo: The Royal Mint.

The Phoenix Ascendant. Photo: The Royal Mint.

Gordon Summers / The Royal Mint: The Future of Craftsmanship in a Technologically Advanced Business

The presentation given by Gordon Summers, Chief Engraver of the Royal Mint, was a very good match to the previous lecture. He contrasted the incredibly complicated traditional method of minting die production with the much faster production based on computer design and laser technology.
He pointed to the problem that the general public, and hence customers of commemorative coins, still assume that all matrices are being designed by an artist manually.
The question is how to response to this? Does the customer’s perception call for more or less technology? Or may it be wiser to attempt to change customer’s preconceptions?
Gordon Summers gave an answer befitting a coin technician enthralled by technology. The logical response would be to use better and faster technology in minting. The Royal Mint had applied all kinds of technological methods currently available for a medal named Phoenix Ascendant (= rising phoenix). The result is a so-called “masterpiece” of which only two examples will enter the free market. 

Rüdiger Böhm / Rösler Oberflächentechnik: Surface preparations for the minting industry

In his presentation, Rüdiger Böhm talked about the latest developments regarding surface preparations of commemorative and circulation coins as well as minting dies. In the sector of commemorative coins, the machines MPA 07.1 E/SA and 17.1 E/SA now skip the steps that involve tumbling in the Centrifugal Tumbling Machine, which considerably improves the quality of the coin blanks.
Concerning the circulation coins, Rüdiger Böhm introduced intermediate hoppers, whose inclination angle can be adjusted, which makes it easier to control the dosing of coins in the machine.
Speaking of control: Thanks to state-of-the-art-computer technology, it is now possible to control the cleaning of the coin blanks from outside the machine.
Rösler has a patent pending for the automatic optimal gap adjustment for its Centrifugal Tumbling Machines. The new technology is expected to generate less maintenance, lower cost for spare parts and an increased production capacity.
Rüdiger Böhm likewise introduced an innovation for the processing of minting dies. Using rotary vibrator technology with plastic-based grinding media, it would only take about six hours processing time and about an hour of dry polishing to gain very good minting die results. 

Ingo Löken / Spaleck Oberflächentechnik: New innovative drying / anti-tarnishing protection methods within the surface finishing process for circulation coin blanks

The presentation held by Ingo Löken of Spaleck revolved around the best way to dry up to 1,600 kg circulation coin blanks per hour. In December 2015, Spaleck has put an entirely new machine, the Z44 BFC into operation which processes twice the amount the machines of the past were capable of. It works with a completely new drying concept.
Since the 1990s, the drying of the cleaned coin blanks was based on hot air, which was used to blow-dry the blanks, as in a kind of giant hairdryer. Yet the high temperatures caused damage to the coin blanks’ antitarnishing protection. Therefore, the new Z44 BFC is based on a different kind of drying: A predrying by cold air is followed by drying on a high-tech textile inlet. This system achieves considerably better drying results and can easily be implemented into existing systems. It allows creating coin blanks in circulation quantities of such a quality that was hitherto only known from blanks made from precious metal. 

Martin Stahlschmidt / Gräbener Pressensysteme: High-Speed Pick&Place System for Gräbener Flexmedal FM250

In his presentation, Martin Stahlschmidt, new CEO of Gräbener Pressensysteme, focused on Flexmedal, a minting press specifically developed for the production of smaller top-quality outputs. With a press force of 2500kN and the automatic “Pick & Place” transport system, it is capable of minting up to 10 coins per minute with a diameter of 50mm and a thickness of 4mm.  
The high press stiffness allows obtaining excellent minting results. Thanks to a reduced striking speed close to the bottom dead center, a brilliant surface quality is guaranteed. 

Siemowit Kalukiewics / Mint of Poland: Tarnishing - No Problem any more

The final speaker of this day was Siemowit Kalukiewics who have sprung more than one surprise at the previous Technical Fora. Just remember – to mention only one example – the first spherical coin of 2015 which he introduced at the 2015 World Money Fair.
This time, Siemowit Kalukiewics dealt with coin tarnishing. Appreciated as patina in classical numismatics, the process of sulfur, which exists in the air, reacting with the silver of the coin thus creating silver sulfide and forming unattractive spots on the coin’s surface, is rather unwelcome in contemporary numismatics.
Very likely the most well-known kind of protection against this process is the transparent capsules in which many coins are sold nowadays.  
Siemowit Kaukiewics introduced a new technology called nSILVER. It is based on a coating with a mere thickness of 10-90 nm. To give you an idea:  1nm equates 10-9 meters – in comparison, a human hair is about 1000 times thicker. Consisting of aluminum oxide and titanium dioxide, the coating is applied though ALD (= Atomic Layer Deposition). The Mint of Poland has developed this new technology in co-operation with Beneq, an expert for ALD coatings.
In Tucillo-Nielsen tests the so coated coins remained intact to a hitherto unknown extent.
The method is also applicable for colored coins and coins with a high relief. 

As usual, the substantial presentations were followed by an enjoyable get-together, providing the opportunity not just to ask the speakers additional questions but to revive old friendships and make new friends. 

Please find the first part of the presentations held at the World Money Fair’s Technical Forum here


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