| Mold is the primary technics equipment of all sorts of production, and it is an important target that weighs the extent of one country's industrialization. Meanwhile, milling is one of the most efficient mold cutting methods, and has got wide applications in various manufacturing industries, but there are still a lot of technical problems in NC milling process left to solve. The thesis mainly focuses on the factors influencing the surface quality of numerical control milling. The main achievements of this thesis are as follows:Aiming at several key process parameters including spindle speed, feed rate and cutting deepness, experiments were designed, and which were carried out on a Wintec MV-80 machining center by cutting a Cr12 steel part. The cutting force is detected online by a piezoelectricity measure instrument called YDX—Ⅲ9702. By analyzing the experiment data, establishing the model of cutting force, and analyzing the influence to the surface quality.Aiming at three kind of routes including transverse cutting, lengthways cutting and 45°cutting, experiments were designed. Then using Scanning Electron Microscope S-3500N to observe the wear of tools and analyzing the influence to the surface quality. Whereby, the theoretical basis for rational selection of process parameters can be provided.Special experiments were designed in orthogonal design method. Based on the research of every single parameter, the relationship between them was discussed, so that some regulation of their combined effect on the surface quality could be found. Then reference values of common process parameters were provided according to different conditions.Synthetizing the last three experiments'researching and analyzing, a new method of optimization based on Genetic Algorithm(GA) was proposed, then establishing and correcting the math model. In the end, a parameter database was established, which can provide selection parametres for the fieldwork. |
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