Tests for the Optimization of Cut-Off Parameters for Seven Galician Granite Varieties

The ornamental rock sector in Galicia (NW Spain), in particular the granite extraction and processing sector, has undergone tremendous development in recent years as a direct consequence of the use of non-aggressive rock mass extraction methods and the progressive modernization and automation of the different processes for processing and finishing the slabs, as well as the improvement of in-plant logistics. Nevertheless, it has been ascertained that cutting parameters entered as setpoint values in the diamond circular saws, used for the subdivision of slabs of the different commercial granite varieties, do not fit clear technical criteria for the optimization of cutting efficiency, but are selected and pre-set based on the experience of the circular saw operator. In order to evaluate the validity of thus selected cutting parameters and to provide the sector with a more objective tool, the cutting performance of seven granite varieties from Galicia which have high sales was analysed. Thus, each available slab was subdivided using four different cutting settings resulting from modifying two of the parameters which most affect cutting efficiency: cutting speed (m/min) and cutting depth (mm). These parameters, in turn, have an influence on power consumption (kWh), diamond saw blade wear (mm) and average production (mm2/min). Thereby, an exhaustive data acquisition process was carried out in order to create a complete database with the representative information of the cutting of each of the seven tested varieties and determine the optimum configuration for cutting each material, based on the results of a graphical analysis of the mean of data and the analysis of the variance (ANOVA).