Abstract
The study deals with manufacturing curved holes such as water channels of mould and die, which are difficult to create. As holes are generally formed by drilling operations, curved holes are approximately formed as the combination of straight holes, which leads to the interference with smooth stream of coolant. To solve the problem, a quite simple mechanism to create a curved hole was devised, which consisted of a helical compression spring, wires, pulleys and an electrode for electrical discharge machining (EDM), and was installed on an electrical discharge machine. The mechanism allowed the electrode to move along a curved line. However, the length of machinable curved hole was not necessarily sufficient. Therefore, the structure of the device was improved so that the electrode can move longer than the prototype along the curved line. From experimental results, it is found that the improved mechanism enables a longer curved hole machining. In addition, L-shaped curved hole could be obtained by connecting two curved holes machined from two perpendicular directions.
