1. Counterfeit of One Pound Coins \ Qingwei Wang Department: Mechanical Engineering Technology Introduction : Two main production routes for the manufacture of one pound counterfeit coins, one is cast lead or tin based pieces coated with brass and the other one is struck brass pieces. Most of the counterfeit coins are cast copies. Cast coinage is great in quality but eventually will wear due to the nature of material what they were made from such as lead or tin. However, struck brass pieces coins in circulation are harder to be identified as counterfeit coins by bank machines and tellers, and that is why most counterfeit coins in circulation are struck brass pieces. Overview: The company of Goldsmiths will test the coins and decide if they have been properly minted. Assayers will test each value of coin by chemical composition, weight and diameter. There are several case analyses for counterfeit coins Case 1 Physical way of detecting the counterfeit coin was by observing the microstructure. This observation found out that microstructure of counterfeit coin has large irregular grains due to non equilibrium cooling from the liquid state. Legally minted wrought copper nickel alloy coin has smaller equi-axed grains as the result of drawn out in direction of work. Case 2 Inflation of coin resulted in replacement of replicate the colour. The thickness of the coins can tell whether or not they are counterfeit. Counterfeit coins are thicker than legal coins because they were produced by casting in a lead or tin based alloy, and electro plated in brass to replicate the colour. Case3 Observation of one pound coin on head, tail and edge. The faces of suspect coin were not of a crisp sharp quality as ordinary faces of coin. Case 4 Metallographic examination was used to explain a manufacturing route. Polished and unetched sections of both suspect and genuine coin of microstructure of each. Polished unetched suspect coins material contained air and etched suspect coins containt dust particles. Air and dust particles will not contain on genuine coin produced by the Mint. Reduce Counterfeit : The chemical data shows that copper made coins has higher chance to be imitate by counterfeit than nickel made coins, because copper is cheap material than nickel. Coins made of nickel have less counterfeit because nickel is high cost material. We can minimize counterfeit coins by increase the nickel constituent that way will increase material cost to the counterfeit. Solving Counterfeit Problem : The most common method of detecting counterfeit pound coins is to check whether the reverse matches the edge inscription for the alleged year. We can solve counterfeit coins problem by the coin making technology because modern coins have unique levels of electrical conductivity and resistivity, so when a coin is inserted into vending machine, it will only be accepted with right electrical signature. It is most effective way to reduce counterfeit coins. Abstract : This paper reviews the current literature on Science Direct about Counterfeit One Pound Coins Analysis. This literature used some methods to determine whether or not the coin is counterfeit or not. More specifically, it was searched to determine what techniques were used to make counterfeit coins by comparing fake coins with real coins. On July 9 th 2003 Paul Boateng from Treasury representative stated in a Parliamentary collected one pound coins and approximately one percent was counterfeit. 1410 million pound coins in circulation from 2003 to 2004 and approximately 14 million of them were counterfeit. Microstructure obtained from a cast counterfeit 50p coin. Image A is counterfeit and B is genuine Suspect coin on the left were not of a crisp sharp quality than genuine coin on the right Image Analysis : Reference : http://www.sciencedirect.com/science/article/pii/S1350630706002044