What are the main production processes of precious metal commemorative coins?

The production process of precious metal commemorative coins is mainly divided into

1. Mirror surface is a traditional coinage process, which mainly polishes the surface of the mold and blank to obtain a high degree of polish on the coin surface. Smooth and smooth. Most of our country's precious metal commemorative coins use this technology, such as the first set of gold coins issued by New China - the 30th anniversary gold coins of the founding of the People's Republic of China. 2. Sandblasting As another traditional coinage process, the mint uses metal sand grains of different sizes to spray the selected pattern part of the commemorative coin mold into a fine frosted surface to enhance the layering and three-dimensionality of the coin surface pattern. Like the mirror process, most of my country's precious metal commemorative coins use this process, such as the gold coins commemorating the 40th anniversary of the founding of the People's Republic of China. 3. Concave engraving This is a unique method of Chinese coin engraving, which uses the principle of metal refraction to use concave engraving on the relief of the coin surface to express the black and white colors of the fur of the panda gold and silver coins. This process was used on the back of the 1983 Panda gold and silver coins. 4. Bi-metal: Two kinds of metal blanks are made in advance, and finally they are die-cast and formed by the mold at one time. The metals are squeezed against each other to achieve a stable combination. The front and back of the coin have the same effect. Our country's precious metal commemorative coins generally use gold and silver bimetal. Examples of this technology: the 1990 Panda Refined Gold Coin and the 1/2 ounce Millennium Commemorative Gold Coin issued in 2000. 5. Electroplating: According to the design and aesthetic requirements of the commemorative coin, other metals are electroplated on part or all of the selected patterns on the coin surface. An example of using this technology: the commemorative silver coin celebrating Beijing’s successful bid for the Olympics. 6. Inlay: Other metals are inlaid on a metal blank and stamped. my country's precious metal commemorative coins basically use gold inlaid with silver or silver inlaid with gold. 7. Middle hole According to the special aesthetic and design requirements of commemorative coins, strong stamping is used during casting to form a hole in the middle of the coin surface. The Datang Zhenku gold and silver commemorative coins issued in 1998 adopted this process. 8. Special shapes: Circle is the traditional shape of coins. In order to reflect innovation and express special themes, Chinese precious metal commemorative coins adopt various shapes such as rectangle, fan-shaped, plum blossom shape, polygon and so on. For example, the fan-painted commemorative silver coins of Ming and Qing Dynasties are fan-shaped coins. 9. Color: The mint combines traditional painting art with coinage technology, and uses special printing plates to pad-print four-color inks, including red, yellow, blue, and black, onto the surface of precious metal commemorative coins. The first colored coin issued by our country was the 1/10 ounce colored gold coin for the Year of the Tiger issued in 1997. 10. Character rolling on the edge thread teeth: Use the method of billet rolling before casting or rolling after casting to cast characters on the edge thread teeth. An example of using this technology: The 1/2 ounce gold coin issued in 1999 for the 50th anniversary of the founding of the People's Republic of China has the words "ZHONG GUO" cast on the edge. 11. Invisible engraving The gold and silver commemorative coins for Macao’s return to the motherland issued in 1999 (Group 1) and the 2001 Mid-Autumn Festival silver coins used this technology. 12. Symphony: Also known as laser engraving, high-energy laser beams are used to etch high-precision lines on the surface of the mold, so that the surface of the commemorative coin presents a multi-layered light effect. The 2002 Guanyin Symphony Commemorative Gold Coin adopted this technology. 13. Deep corrosion of the blank cake. Special chemical reagents are used to polish the blank cake, making the mirror surface of the commemorative coin particularly bright. This is an example of the silver coin commemorating the 100th anniversary of the discovery of the Dunhuang Scripture Cave using this process. 14. High relief: Compared with the traditional low relief, higher relief is used to express the layering of the commemorative coin pattern. The Dunhuang Grottoes 2-ounce silver coin issued in 2001 adopted this process. 15. Borderless The traditional clear edges on the surface of commemorative coins are cancelled, to express special effects. This process was used in the 2001 Panda gold coin and the Longmen Grottoes 1kg silver coin. 16. Helical teeth: A special stamping method is used to make the perpendicularity between the coin teeth and the coin surface greater than or less than 90°C to prevent counterfeiting. This technology was used in the 2001 Panda gold coin and the silver medal commemorating the first anniversary of Beijing's successful Olympic bid. my country's Shenzhen Guobao Gold Coin Manufacturing Factory has maturely mastered this technology.