Diamond wire cutting technology and workability of natural stones: validation of a new classification method (EASE R3)

Abstract

In the diamond wire stone cutting process the objective is to remove a chip of material or a layer of uniform thickness from the entire length of the cut. The aim of this study is to correlate the cutting performance to the characteristics of the natural stone and subsequently to propose a method of classification strictly connected to stone workability. Hardness and micro-hardness tests are currently considered important methods for acquiring useful information about the workability of natural stones, but such gathered data alone do not give enough information to establish a satisfying classification. The concept of workability and stone machining has been, for the past thirty years, one of the main area of investigation in national and international researches. This study endorses a method for the prediction of stone-cutting tools interaction (mainly diamond wires) combining the micro-hardness and the UPV measurements, that better represent the mechanical, physical and petrographical stone properties. This paper studies eight different stones classified according to an “easy-to-cut” scale based on the historical company know-how (HIC - Historical Industrial Classification). This classification is based upon experience and not on explicit or really scientifically quantified parameters, nonetheless, it describes the stones workability completely. In previous works, however, criteria based on quantifiable parameters (SSC - Scientific Stone Classification) have been pursued and this led to a scientific correlation with the industrial classification. For each stone the following investigation techniques were performed: petrographic analysis, micro-hardness, Schmidt rebound, Ultrasound Pulse Velocity (UPV). Moreover UPV measures in indirect and direct method have been executed on stone blocks in the cutting plant and compared with those performed on slabs. The results of all the performed tests were analyzed and good correlations with the industrial classification were found. Introduction