Views:0 Author:Site Editor Publish Time: 2019-11-29 Origin:Site
Today, more and more people are paying attention to and purchasing modern precious metal association souvenir coins, especially the world's top five investment coins, mainly Chinese pandas, Canadian maple leaves, Australian kangaroos, South Africa's Vogelingen and American Eagle Ocean. However, although the coin collection has entered millions of households, do you know the production process of these custom commemorative coin for sale?
Selection of materials
Silver coins generally use pure silver with a purity of 99.9%, and the most used internationally are 92.5% and 90.0%. Gold coins are generally minted with 99.99% and 99.9% gold. Both gold and silver are purified and prepared by the electrolytic refining of the mint, and analyzed with modern instruments to form points. The analysis results represent a country's authoritative standards and advanced technology.
Rolled strip version
From the electric furnace, the molten noble metal is cast into continuous slabs of various specifications through a continuous casting machine, and the surface is mechanically milled to remove impurities, and then cold rolled under extremely strict environmental requirements. Each process must be kept clean.
Washing cakes and cleaning
The blanks to be stamped must be guaranteed to have minimal burrs and edges, and to avoid any contamination and scratches, and then be annealed and then polished. The surface of the cake is dried with a special detergent. Each cake is weighed. The accuracy of the electronic scale is 0.0001 grams. All the cakes that do not meet the tolerance are discarded. Put the perfect blanks that meet the requirements in the specified quantity in a clean, covered container to prepare for imprinting.
Mold design is a unique and important link in the coinage process. Subjected to strict scrutiny, the motif is intricately carved and carved in the mint, combined with the use of modern precision equipment, and the design intention is expressed on the mold. In order to highlight the visual effect, the embossed body of the depression has a delicate frost surface, and the high places need to be ground into a mirror surface, and no defects can be found on the high-magnification projection screen.
Embossing is performed in a clean room with air filtration. Any tiny dust is the root cause of coin scrapping. The scrapping rate of stamping is usually 10% internationally. For coins with large diameter and large mirror area, The scrap rate is as high as 50%.
Protection and packaging
In order to maintain the original color of the souvenir coin for a certain period of time, the surface of each coin must undergo a certain protection treatment. At the same time, it is placed in a plastic box, sealed with a plastic film, and then loaded into a specially designed Packaging box, and all finished products are finally subjected to strict inspection.
The production of a souvenir coin goes through so many sophisticated 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 of the quality and reputation of the mint. It is the crystallization of the efforts and sweat of designers and producers.