Development And Research On WEDM Automatic Programming Based On Images From A Scanner

The wire electro discharge machining (WEDM) is widely used in manufacture of moulds, various difficult-to-machine materials, molding cutters, parts with complex surface and the like. To simplify the programming task and to improve the working efficiency, the trend of automatic programming with computers is inevitable. In numerical control machining field, the processing requirement that dimension is based on arts and crafts pictures or practical parts becomes more and more popular, thus the automatic programming system, of which the images are obtained by being scanned with a scanner, is necessary in the numerical control automatic programming system besides the automatic programming system based on drawing dimension.This paper is based on the XoY software (the DOS version), and according to practical processing requirements, the automatic programming system, of which the pictures are obtained from a scanner, is developed after reviewing the automatic programming software in prior art. Using the Windows operation system as a platform, the software is more visual, more practical and easier to use.The main functions of the system include image obtain, image vectorization, curve fitting and programming of processing program, wherein the images are obtained from the scanner as dimensional foundation. Not only white-and-black image but also true color image can be recognized; not only hollow image but also solid image can be processed by the system; the graphic after vectorization can be fitted in the range of specified precision, the machining paths can be calculated according to process conditions given by users, and the 3B code or G code used by the WEDM machine tool then can be generated by means of corresponding modules, and finally the 3B code or G code can be transferred to the single board computer to control the machine tool. Besides, the system is provided with a standard interface for graphic files, and the system can read and output DXF (AutoCAD) files. The software, with creative contour extraction algorithm and contour tracing algorithm, simplifies the programs and improves the operation speed during image vectorization; the curves can be fitted under precision limits by approximation and linear and arc fitting, the length of the machining program is shortened and high efficiency programming machining of curves is realized.Tested and used by Jinan Kete electric machining technology limited company, the system proves that the interface is friendly, the operation is convenient and the system is easy to learn and use; compared with other similar software systems, the system has higher precision with same amount of machining programs and has shorter program under the same precision; the system has a good popularization and application prospect.