Development of CAM System Based on Simulation of the Copy Operation – An Application to the Boundary Representation Method and High Efficiency Machining –
Masahide Kohya*, Hiroyuki Narahara** and Hiroshi Suzuki**
*Industrial Technology Center of Fukui Prefecture, 3-6-1 Norimatu, Hatimannishi-ku, Kitakyusyu-shi 807, Japan
**Faculty of Information Engineering, Kyusyu Institute of Technology, 680-4 Kawatsu, Iizuka-shi, Fukuoka 820, Japan
A CAM system, based on a simulation of the servo data generation method of a copy milling machine, was developed. In this system, the tool path data can be calculated directly using the coordinates of the contact point between the defined shape and an imaginary stylus, without the preceding processes of generating an offset surface and checking the tool interference. For application of this algorithm to a model which is expressed using the boundary representation method, the algorithm was modified slightly. Since the contact point is regarded as the point nearest to the center of the imaginary stylus, which is on the model surface, all the intervals between the center of the imaginary stylus and the constructing surfaces which are close to it are calculated. The point which has the shortest interval is the nearest representative point of the model data and the contact point, in the case in which the interval is equal to the radius of the tool. A rough tool path, which is composed of an imaginary block and a spiral finishing tool path, which enables tools to feed with smooth cutting has been developed using this algorithm. Toolpath simulations and cutting tests show that the CAM system developed was able to generate appropriate CL data with high accuracy and reliability.