| To overcome the many difficulties in manufacturing free form surfaces on a 3-axis milling machine, the design and implementation of a new NC controller is presented. This controller implements in real time a surface generation technique and a tool positioning method. Previously, these functions were performed off-line by a second dedicated host computer. By shifting the responsibilities from the host to the controller, less data has to be transmitted; thereby, minimising the chances of errors such as lost or incomplete data from occurring. By lessening errors the possibility of damage to the tool and machine is decreased while the safety of the machining operation is improved.;The controller implements the B-spline surface generation technique which only requires a small amount of data, namely the control mesh of the surface, to create a mathematical model that represents the true topology of the surface. Once a model of the surface is known, a tool positioning strategy called the Projection Method is applied to generate tool paths that allows gouge free surfaces of any orientation to be manufactured. (Abstract shortened by UMI.)... |
