Better stone-cutting processes to boost SMEs
The EU market share for processed stone has been decreasing steadily over the last few years, losing out to relatively new stone-producing countries (i.e. China and India). These problems are related to stone processing and particularly granite slab production, which is facing low productivity, huge quantities of waste material, high energy consumption and challenges related to the environmental management of wastes produced. The EU-funded CLEAN CUT project implemented a new concept for a granite slabbing machine. This has the potential for high energy savings per square metre, low environmental impact, greater versatility in work programming, high productivity and high-quality surface finishing. To achieve this, the project partners developed a cost-effective small-diameter diamond wire with a longer life cycle based on super-elastic nickel–titanium alloys (Nitinol). Their research involved defining and optimising the thermo-mechanical production process for the wire that would ensure its mechanical performance and lifetime. They also developed the necessary joining methodology for the alloys, and characterised the mechanical and fatigue behaviour of the joint. Finally, a complete model integrating the properties of the wire was developed. This integration helps to define the optimum set of algorithms for process control. At the end of the project, a 7-mm–diameter cutting wire with diamond beads was produced. It demonstrates better fatigue resistance, damping behaviour and ease of manufacturing, and is suitable for low-cost cutting machines. CLEAN CUT results offer a huge opportunity for the project's small business participants and the overall stone industry, which employs some 500 000 people in 60 000 companies. The consortium partners also acknowledged the need to transfer the technology to a wider industrial community in order to boost competitiveness and employment in this important EU sector.