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China is one of the earliest countries to use precious metals to mint coins. When precious metals were first used as currency in circulation, there was no unit of weight verified and recognized by authoritative institutions. In order to solve this problem, people invented minting technology. With the application of many high and new technologies in the coinage industry, the casting technology of precious metal commemorative coins is progressing day by day, and the level of technology is constantly improving. The use of cleaning agents in the mint process is critical and requires the usePrecision metal cleaning agent, and high requirements for precision metal cleaning agents, strong ability to remove oil on metal surfaces, Ruibao brandRSB-105 alkaline metal cleanerorRSB-102 precision metal cleaning agentIt has excellent oil performance. The following article describes the application of precision metal cleaning agent in the coinage process. The casting process mainly includes the following steps.
Selection of materials 1
Silver coins are generally made of pure silver with 999 purity, until silver-containing 500 silver-copper alloy is made, and the most used internationally is the fineness of 925 and 900. The copper-rich phase of the silver cake oxidation faster, easy to pan dark, so the low color of the silver cake to use the surface of the rich pure silver process. Gold coins are generally cast in gold, silver or gold-copper alloys such as 9,999,999 K. Whether gold or silver are refined and prepared by the mint electrolysis, and analyzed into points with modern instruments, the results of which represent the authoritative standards of a country.
Fused Strip Version 2
The molten precious metals from the electric furnace are cast into slabs of various specifications through a continuous casting machine, and then the surface is milled mechanically to remove impurities, and then cold rolled under extremely strict environmental requirements. Each process must be kept clean. After annealing, a mirror-shiny strip with a very small thickness tolerance is rolled on a special finishing mill with an error of no more than 0.005mm.
Pie, Cleaning 3
Place the strip on the blank cake from the punch, ensure that the minimum burr and the best edge are obtained, and avoid any contamination and scratches, and then perform bright annealing and polishing. The surface of the blank cake is dried with a special cleaning agent. Each blank cake must be weighed. The accuracy of the electronic scale is 0.0001 grams. All blank cakes that do not meet the tolerance are scrapped. Place the mirror, bright, perfect blanks in strict accordance with the specified quantity in a clean container with a lid for embossing. Coin is a precision metal, the general choice of cleaning agent requirements can quickly clean the precision metal surface oil and cutting fluid and other dirt. It is recommended to use the low-foaming alkaline metal cleaner of Ruibao brand.
Mould and cleaning 4
Mold design is a unique and important link in the coinage process. After strict examination of the subject matter, patterns, through the mint's complex and superb fine carving, combined with the use of modern precision equipment, the design intention chart is shown on the mold. In order to highlight the visual effect, the main relief of the depression has a delicate frost surface, and the higher places need to be ground into a mirror surface, and no defects can be found on the high-magnification projection screen. As a common printing tool, the mold needs to be cleaned regularly. Ruibao brand mold cleaning agent, used to clean the mold steel surface oil, organic residue, hand sweat, dust, etc.
Stamping 6
Imprinting is carried out in a clean room with air filtration. Any tiny dust is the root cause of coin scrap. The scrap rate of imprinting is usually 10% in the world, while the scrap rate of coins with large diameter and large mirror area is as high as 50%. Blank cake with any defects can only be sent to the sealed mold cavity by hand, and it is difficult to achieve the same quality by mechanical feeding.
Protection and packaging 7
In order to maintain the original color of the commemorative coin within a certain period of time, the surface of each coin must be treated to a certain extent. At the same time, it is placed in a plastic box, sealed with plastic film, and then put into a specially designed packaging box., And all finished products will eventually undergo 1% strict inspection.

The production of a commemorative coin has to go through so many sophisticated and complex procedures. When you collect these exquisite works of art, in addition to appreciating its artistic value and commemorative symbol, don't forget that it is also a witness to the quality and reputation of the mint. It is the crystallization of the painstaking efforts and sweat of designers and producers.