Measurement and Control Methods of 3-D NC Press Machines for Forming Springback of Ship Steel Plates

Aiming at the problems of ship plate forming spring-back in theory and experiment, combining the law of sheet metal forming, this paper puts forward a measurement and compensation method of spring-back outside plate of a ship based on the three dimensional NC (numerical control) pressing machine. First, we use Dynaform software for finite element analysis of springback prediction, and then establish the model in the UG to generate the initial surface data, after those we make the first time stamping. After forming, we measure the surface shape of the work piece by a self-developed non-contact measurement of 3D laser rebound measuring device, and then analysis the spring-back. According to the spring-back data measured by body, we can use least squares fitting approximation mould surface, then adjust the lower mould basic body group tool surface shape to make stamping one more time. After 1~2 times prediction, basic body surface shape modify and stamping, it finally realize the purpose of controlling spring-back and forming well. Finally, examples show that the method is feasible, and the rebound quantity can be controlled to the allowed precision, the complex problem of plastic forming spring-back ship surface is effectively solved.