| 摘要 |
coin manufacture. SUBSTANCE: method involves forming decorative surface with profile of isosceles trapezium on billet; embossing microrelief of symbol members and forming different types of patterns and stamping billet. Decorative surface on end of billet is made in the form of groove by squeezing billet along perimeter of end, with following depression of tool with related profile. Angle between trapezium sides is 5-25 deg. Microrelief on lower base of trapezium is created before stamping process. EFFECT: simplified method and improved protection from counterfeit. 1 dwg |
