High efficiency surface finishing of metal mold by large-area electron beam irradiation (1st report) - Possibility of smoothing of EDMed surface and analysis of fundamental machining characteristics

A new finishing process for metal molds by large-area electron beam irradiation is proposed in this study. In the large-area electron beam irradiation equipment used here, the electron beam with a maximum diameter of 60mm can be used for melting or evaporating metal surface. Experimental results show that the roughness of the irradiated surface becomes smaller with increasing the energy density of beam and the number of irradiation, but excessive energy density and too many irradiations make it a little worse. Under a proper condition, the surface roughness decreases from 6 μm to less than 1 μm in just a few minutes. The glossiness of the surface also can be improved very well. By observing the cross section of irradiated surfaces, it is confirmed that the material removal is performed just on the irradiated surface without any resolidified layers. Moreover, the surface roughness after irradiation becomes smaller when the roughness before irradiation is small. Therefore, large-area electron beam irradiation method has a high possibility of high efficient finishing process for metal molds.