Optimization of stone processing using diamond tools

Informations projet

N° de convention de subvention: BRST965094

Projet clôturé

Date de début 1 Février 1997

Date de fin 30 Avril 1999

Financé au titre de

• Specific research and technological development programme in the field of industrial and materials technologies, 1994-1998

Coût total € 0,00

Contribution de l’UE Aucune donnée

Coordonné par

FABRIMAR - INDUSTRIA DE ROCHAS E EQUIPAMENTOS SA
Portugal

Résultats exploitables

SPUD - Optimization of Stone Processing Using Diamond Tools

The SPUD project aimed to investigate the improvement in productivity of stone processing by the use of diamond tools for slab and edge polishing. In support of this aim, suitable diamond tools needed to be developed along with a prototype slab-processing machine. The latter was to be used to test the diamond tools and to research into the effect of processing conditions on the quality of the stone surface with a view to establishing optimum processing conditions for diamond tools. It is apparent that the optimum processing conditions for different stone materials would be different and therefore an attempt has been made in this project to develop a procedure and a parameter for providing a good indication of the relative abrasiveness of stone materials with a view to evolving a stone classification system. Work has also been carried out to find a correlation between the relative abrasiveness and the intrinsic macromechanical stone properties i.e., Hardness, Young's modulus, Fracture toughness and flexural strength and although not yet conclusive, this work indicates that it is possible to classify ornamental stones for processing according to their macromechanical properties. An experimental programme using standard orthogonal arrays as proposed by Taguchi and Wu revealed the relative influence of various processing parameters on the quality of the stone finish. However, for determining the optimum processing parameters, a large number of further tests will need to be carried out using a more appropriate machine. The test programme also established that except for the final glosex stage, the diamond tools can be used for all stages of stone processing and the number of stages required with diamond tools is less than half of those required with the conventional ceramic tools. The test results have also been used to develop mathematical models for different stages of stone processing with the stone hardness being one of the variables. Using these models, a prototype Knowledge Based system (KBS) has been developed which recommends optimum conditions for different stages of stone polishing for a given type of stone material. The original intention was to include experiential knowledge in the KBS along with the mathematical models but it proved difficult to gather experiential knowledge from the experts. Following the experimental work, industrial tests for both slab and edge polishing were carried out which confirmed the effectiveness of diamond tools for almost all stone processing stages and which demonstrated that the waste sludge coming out of the production line, which is generally a big problem with ceramic tools, was almost absent when diamond tools were used. The SPUD has thus given a firm basis for use of diamond tools for stone polishing with the consequent benefits to the stone sector in terms of improved productivity and a cleaner technology. The project has advanced the research base in stone processing technology which if taken forward would create a better understanding of the process and would lead to further development of diamond tools and the processing machines.