Attività

Grinding with a Glass Grinding Machine is the main machining process for producing glass workpieces. However, cutting forces during grinding result in the formation of damaged surfaces which require a polishing operation to complete the machining process. Moreover, damage may propagate under the surface, causing the workpiece to break. Thus, it appears necessary to control the surface damage and roughness during the grinding process.

In order to characterize ground glass surfaces, Ra is the main normalized parameter being used. Yet this parameter doesn’t allow the detection of crack growth. We propose here to characterize ground glass surfaces using more appropriate 2D and 3D roughness parameters, such as the ones extracted from the Abbott-Firestone curve Rk, Rvk, Mr2 and their 3D equivalents. Using these parameters, we have determined cutting conditions that improve surface roughness of ground glass workpieces. Considering the large amount of parameters defining the grinding process, a design of experiments using response surface methodology has been developed for this purpose. We have determined optimized cutting conditions that allow to minimize depth and amount of valleys on the brittle material surface, and thus minimize the crack propagation risk.