Shining the Future – Papers of MDC Mexico: Technical

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by Ursula Kampmann
translated by Honeycutshome

July 8, 2014 – From May 11 to 14, 2014, the Mints were meeting in Mexico. As usual, the sessions were divided, so that the one group discussed marketing issues while most of the participants listened to what had been worked out in the many sub-committees in the context of the Technical Committee.

Prabir De, leader of the Technical Committee and hence responsible for appointing the speakers, was quite pleased at the end of the day about how many current topics and series of tests had been incorporated into the papers given. While the Technical Forum of the World Money Fair is something of a “shop window” for the companies to present their latest products, at the MDC, in contrast, the working groups of the Technical Committee present the results of their long-term studies. 
If you want to go directly to one of the paper summaries just follow these links:

Monday, May 12, 2014 – Advancement 1
The series of papers addressing technical issues was opened by Sean Bryne of Royal Canadian Mint with his contribution on the evolution of circulation coins with color applied. He contrasted the first coin – a Canadian 25 cent piece from 2004 and a small monochrome poppy flower in the center of the coin – with current, state-of-the-art possibilities. Back then, an ink-jet printer was used that printed the monochrome subject with 4.5dpi.
In co-operation with Teca-Print a special kind of pad printing was developed that makes it possible to produce subjects with 2,000dpi and a diameter of more than 50mm with excellent precision and unlimited color, that – as was proven in many comprehensive series of tests – show superior resistance to wear in the circulation process.
The advantages of the system are evident. Expenditures could be saved in the department of commemorative coins. With circulation coins, the seigniorage could be increased since many users hold back these coins because of their appeal. In the future one might also consider new security applications in the light that it takes a lot of effort to imitate pad printing.

CAD (Computer Aided Design) and CAM (Computer Aided Manufacturing) have not only become established terms in the minting industry, but every-day reality when the goal is the production of low-cost new coin designs. Hideaki Mori introduced the audience to the next level of possible application: CAE (Computer Aided Engineering).
At present, this technology is used mainly in the auto industry. There, the press process is simulated, as it is a similar procedure as minting. Japan Mint had tested the FEM software DEFORM in order to make out potential design weaknesses and potential locations of die cracks even before the coining is actually done. Right now, the system can only point to defaults. It is left to the people to get to the bottom of the problem and find a solution. At any rate, this software provides such great a help in coining that Japan Mint intends to conduct further research.

Bo Deng of the Department of Minting of the China Banknote Printing and Minting Corporation presented his thoughts about the application of anti-counterfeit inks to commemorative coins as it has become standard procedure already with banknotes. The following inks had been tested: UV fluorescent ink, infrared absorption ink, optical variable ink and invisible marker gloss oil. All the inks were developed by a sub-company solely for that purpose.
UV fluorescent ink showed good results, particularly when printed twice in order to accumulate more inks on coins.
Tests with infrared absorption ink likewise were successful. Another possibility is to add a code to the coin that can only be read by a scanner so that forgeries will be immediately recognized as such.
The production of optical variable ink is very expensive which is why it is usually printed only in quite small areas on banknotes. Three inks at once had been developed and tested to the result that the ink with the highest viscosity obtained the best effects, especially when the printing was increased 3 times. The printing process at the same required the highest attention.
Invisible marker gloss oil contains covert security elements which is why a combination with other anti-counterfeit inks is recommended.
All inks call for different methods of pad printing. They are ideally suited to be combined, albeit that requires great effort. 

The last paper before noon was a joint series of tests of Johann Mayerhofer / Böhler Edelstahl GmbH and Xianyao Li / Royal Canadian Mint. In a first step, they had tested different kinds of steel available on the market for their suitability for coining dies. In a second step a material developed by Böhler was introduced that is currently in the test phase. 
At present, the minting industry for the most part uses about 12 different sorts of steel.
The test results were presented in 2013, with the best individual results obtained by: K340 (Böhler), Calmax (Uddeholm), A-88 (Sleipner, Uddeholm) and K455 (Böhler).
A new kind of steel has been developed by Böhler on the basis of powdermetallurgical steel, bearing the name K490 that shows much better results than all hitherto known kinds of steel. It was tested in 2013 for 3 months in 9 different mints. The result was a significant die life increase ranging from about 1.5 times up to 2 times when this new material was used.

Advancement II
Matti Rastas of Mint of Finland, one of the biggest blank producers worldwide, addressed a problem that is affecting mints and blank producers at regular intervals. What criteria should the testing of the blanks’ quality follow?  The different interests of producers and consumers call for a universally accepted agreement. In order to define a standard that will be accepted worldwide a questionnaire was sent to the MDC members for finding out the practices of the sampling procedure. The result proved that the euro producing mints follow their own standard while the other mints adhere to a number of international standards. The producers should accept that and forward it to central banks and ministries alike.

Dr. Phil Carpenter of The Royal Mint presented new trends of iSIS, which is short for Integrated Secure Identification System, a system developed by the company of a machine readable, full plated coin that offers banknote strength security at low cost. He announced that this new technology will be adopted in the UK on a new £1 circulating coin to be released in 2017. iSIS is incorporated into the plated layer of a coin during the production process and detected using optical sensors.  This feature is uniformly distributed throughout the full plated layer and the signal is, therefore, detectable throughout the entire lifetime of the coin.

Security was also at the heart of the paper of Eugenio Gomez who talked about “Do’s and Don’ts of Latent Image”. Latent images had become a universal feature in the printing of security papers and documents. Attempts had been made since the 1990s to apply the procedure involved on coining as well.

Tuesday, May 13, 2014 – Optimum Conditions
Woon Hyung Baek of Poongsan presented the audience with a new material for coining, which is still being developed, that showed excellent corrosion resistance and anti-tarnish properties but is likewise considerably cheaper than other materials. In order to produce the predefined white color, Poongsan based the study on nickel silver alloy and considered to change the composition of zinc and other additional elements such as Sn, Si, Fe, and Mn. The effects of various elements in the alloy for anti-tarnish property were tested. In addition, the manufacturing characteristics for these new coinage materials were examined. Mr. Baek presented the results of the elaborate series of tests in detail.
The best of the new coinage alloys reduces the cost of raw material up to 20% compared to cupro-nickel. It is on a par with its model when it comes to color and coinability property but showed better tarnish resistance compared to cupro-nickel.

Next was Peter Huber who spoke about the activities of the Benchmarking Committee. Unfortunetaly, the number of mints participating has dropped until 2011. While in 2011, data had been provided by 21 participants, there were only 7 willing to do in 2012 – too few when compared with the huge differences existing in the coining industry. The size of the companies varies between 30 and 300 employees, and they manufacture between 250 and 10,000 coining dies every year. In order to arrive at a representative study, at least 10 participants would be needed.
That a benchmark can provide an excellent indication was exemplified by Peter Huber with the average coining die life. It covers a span ranging from 67,500 to a maximum of 1,929,927 coins. The greatest influence exerts the power applied in the minting process. Additionally, a high relief impacts negatively on the die.
Another topic was the external view. Seven members of the supplying industry had evaluated 46 mints and 13 blank producers in different categories such as security, hospitality, visitor safety, cleanliness, training and flow. There were huge differences to be witnessed! While some companies scored magnificent 10 or 9 points, others only got 1 or even 0. A similar result was obtained with the technical issues. While the overall age of the machinery in use has decreased compared with 2012, in regard to innovation and maintenance between 1 and 9 points were given. Cooperation and knowledge sharing got the lowest values in the technical rating. That may be a reason why many mints are rather reluctant to share their data with the Benchmarking Committee.
Mints interested to view their individual results are requested to contact Peter Huber. It is a valuable tool to facilitate the self-assessment in a competing market.

The third paper of the day was given by Gustavo Adrian Narvaez Pardo of Mexican Mint who completed his training in Computer Aided Manufacturing at Royal Canadian Mint in the frame of the Janine Murphy Scholarship. He chose this objective because auf the Mexican mint’s desire to develop further in that special area. Royal Canadian Mint he selected as training company because of her excellent mastering of this technology.
Although it had been only three weeks, Gustavo Adrian Narvaez Pardo was highly content with what he had learned and which he immediately put into practice on Mexican coining dies, as he demonstrated to the audience.

Of utmost importance was the contribution of Juan Manuel Shiguetomi who had conducted ample testing how to optimize the polishing process of coin blanks before coining. In cooperation with several mints as well the expert Spaleck he examined circulation coins made of a copper base, a copper plated alloy, as well as a brass plated alloy. The chemicals used in the process did not make any major difference. All compounds used in the different mints obtained ecellent results. It is however important to take care of the complete cycle, ensuring of having first acid, then alkaline and at the end finishing with neutral pH water. In regard to the process, the mixture media, satellite and ball worked very well in solid metal and copper plated coins while it is better to use only satellite 3X5 for the brass plated ones.
The best batch size for coins made of a copper alloy was 180kgs with an ideal process time of 850secs. Process time and batch size have a particular great effect on the polishing process.

Security & Fraud
Unfortunately, participation in this session was restricted to members of the mints so that we cannot give you an account of the papers given. The topics addressed were:

  • Manfred Matzinger-Leopold, Protection of Coins against Fraud and Counterfeiting
  • Takashi Kurosaki, The Relation between Coins and Vending Machines in Japan
  • Johan Khouw, Recent Cases of Euro Coin Counterfeiting

If you want to read about what was discussed in the Plenary Sessions please click here.
If you want to read about what was discussed in the Marketing Session please click here.
If you want to read an article on the entire MDC in Mexico please click here.