First, the choice of materials
Sterling silver medals generally use 999 pure sterling silver, the most used in the world is the 925 and 900 color. Pure gold medals are generally made of gold, silver or gold-copper alloys such as 9999, 999, 22K. Whether gold or silver is purified and prepared by the mint refining and is analyzed by modern instruments, the analysis results represent a country's authoritative standards and technological advancement.
Second, the melting strip version
The molten metal is passed through a continuous casting machine from an electric furnace to be cast into various specifications, and the surface is mechanically milled to remove impurities, and then cold-rolled under extremely strict environmental conditions. A mirror-like strip with a very small thickness tolerance is rolled on a dedicated finishing mill with an error of no more than 0.005 mm.
Third, punching cake, cleaning
Place the strips in the punched out blank and ensure that the smallest burrs and the best edges are obtained. The surface of the cake is dried with a special detergent, and each cake is weighed. The accuracy of the scale is 0.0001 g. All non-conformity blanks are scrapped. The perfect blanks that meet the requirements are placed in a clean lid holder in accordance with the specified number for embossing.
Fourth, the mold
Mold design is a unique and important part of the coinage process. After the rigorous examination and approval of the theme and pattern, through the complex and superb carving of the mint, combined with the use of modern precision equipment, the design of the graphic mold.
Embossing is carried out in a clean room with air filtration. Any tiny dust is the source of coin scrapping. Internationally, the offset rate of imprinting is usually 10%, while the coin with large diameter and large mirror area is The scrap rate is as high as 50%.
Sixth, protection and packaging
In order to maintain the original color of the gold and silver commemorative coins within a certain period of time, the surface of each coin must be treated with certain protection, and then placed in a plastic box, sealed with a plastic film, and then loaded specifically for it. The packaging is designed, and all finished products are ultimately subject to rigorous testing.
Seven, customized process
The improvement of the entire process determines the entire custom delivery cycle, quality issues and so on.