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