Research And Development Of NC Machining System For Character Contours

How to perform NC (numerical control) machining for unsized images directly, rapidly andaccurately is one of advanced manufacturing techniques, which is applied in the fields of fastprototype making of products and work of art making etc. The object contours machining, suchas Chinese characters, numerals, all kinds of signs, brands and so on, mainly are manufacturedby hand at present, but NC machining has begun to be adopted now. Machining by hand has verylower efficiency, and can't get accurate contours. When a carve machine or a cutting machinedeals with the characters, we must to solve the problem of NC auto-programming. Combined thepractical application requirements with digital image processing, computer graphics and NCmachining, a NC machining system for character contours is developed. The system can not onlyget the information of character contours accurately, but also change the lattice images to vectorimages, and finally output NC code for NC cutting in AutoCAD conditions. Input the NC code toNC cutting machine, the machine can cut all kinds of character contours.Firstly the machine structure, hardware structure and software structure is explained. Thesystem uses open numerical control system structural design. The software of image contoursextraction and vectorization and the module of NC auto-programming are introduced later.The software of image contours extraction and vectorization mainly included some functionsub-modules, such as the capture of character objects, the elimination of noise, the colorprocessing of images, the detection of edges, the extraction of contours, the vectorization ofcontours, the creation of vector graph files, etc. It is helpful for the NC wire-cuttingauto-programming of character contours in the CAD software. It is effective and reliable, andcan get character contours with any sizes.The module is developed on the platform of AutoCAD with VBA technology. The mainfunctions of the software are inputting the drawing by the interactive interface, selecting the partof the profile to be machined and then interpolating by adopting the approximate double circulararc interpolated method, making the drawing after interpolation, calculating the error ofinterpolation, and outputting the NC code. It is proved that the application of the system will change original machining by hand, andprovide a new idea for the automation of the manufacture industry. It's has a good projection inapplications.