Gloss and Modelling Studies of Stone Polishing, Using Linear Polishing Machines With Rotating Heads

The ornamental stone industry has always played an important role in the world economy, particularly in building construction. Polishing the slabs to increase its gloss, is an important processing operation to enhance the beauty and richness of these natural materials. Many industrial polishing machines rely on rotating heads movement along zigzag trajectories, eroding the surface as stochastically as possible, to avoid scratches and other visual defects caused by paths too symmetric. The displacement of the polishing head after a single zigzag movement and after a single rotation have been used to quantify the polishing process as these two parameters are related with the final stone gloss and are a measure of the efficiency of the polishing process. Applying experimental and new computer simulation techniques, we studied the influence of these two tool displacement parameters on the final stone gloss, and acquired insight into the accuracy of the simulation techniques that were applied here for the first time. We concluded that: 1) a clear correlation can be established between experimental and simulation data; 2) the two displacement parameters represent an effective way to control the quality and efficiency of the polishing process; 3) there is a limit for the gloss acquired through polishing processes, so polishing above a given threshold decreases the efficiency without increasing the quality.