Final Report Summary - CLEAN CUT (Development of a clean and energy efficient cutting system for the 12 millions tons of granite blocks yearly processed in enlarged EU)
Tesimag has patented an innovative stone slabbing machine which is based on a set of diamond wires operated vertically and not horizontally, thus reducing their length and overall machine foot print while enabling the processing of both regular and irregular sized blocks. The system does not use grits as for current gang-saws and therefore the processing waste is fully recyclable. However, there are still some bottlenecks preventing the direct exploitation of the concept, namely:
1. the larger kerf caused by available diamond wire based on stainless steel strands (10 to 12 mm) when compared to 5 to 6 mm with steel blades;
2. the reduced life-cycle of the wire due to failures of the joints of the steel strands;
3. the lack of a proper control system able to constantly monitor anomalous stresses and deformations, thus guaranteeing the correct functioning of up to 50 wires singularly subject to different stresses because of the variable geometry of the block across the cutting plane.
To solve these bottlenecks, the CLEAN-CUT project has developed a cost-effective small diameter diamond wire with increased life cycle based on superelastic nichel-titanium alloys (nitinol). At first, the thermo-mechanical sequences and training procedures which are needed to obtain a superelastic nitinol wire with the required mechanical performances with respect to the specific application as well as with a stable mechanical behaviour along its whole life cycle and an improved fatigue behaviour were investigated, defined and optimised. In parallel, a proper control logic for process control was developed. Several cable designs were then considered based on the chosen alloy and a proper joining methodology for shape memory alloys (SMA-SMA) was suggested. Test bench characterisation of the mechanical and fatigue behaviour of the joint was also conducted. Integrated cutting wires with SMA core and with diamond beads with an external diameter of 7 mm were finally produced and tested on board of single-wire machines. Measurements were taken from the novel control system and recorded better performances in terms of fatigue resistance, damping behaviour and thus quality of the cut. Other advantages include easiness of manufacturing and suitability for cutting machines characterised by lower manufacturing and maintenance costs. The final solution of the cutting wire worked well in real working conditions, allowing good surface finishing and showing important perspectives that will be made concrete in the next industrialisation phase. The innovative design of the joint will allow to further decrease the diameter of the core and thus the bead diameter: in fact in this case there is not the need of a high number of thin wires that have to be threaded in order to make the joint, like for traditional strands. To do this new diamond beads have to be manufactured and tested and some significant changes have to be done on traditional machines, in order to make these ones adapt to be equipped with the new wires.
The participants to the project were:
1. Tesimag Srl: small and medium sized enterprise (SME) - Coordinator - Italy
2. Master Tre Srl (SME) - Italy
3. Mc Diam Sp z oo (SME) - Poland
4. Kohlhoff and Raatz GmbH (SME) - Germany
5. Centro di Progettazione, Design e Tecnologie dei Materiali - CETMA - Research and technological development (RTD) - Italy
6. Centre de Ricerca I Ivestigacio de Catalunya SA - CRIC (RTD) - Spain
7. Tevan Srl (RTD) - Italy.
Project objectives and the main public domain results are available on the project website, at the address http://www.project-cleancut.eu For further details and description, please contact Mrs Sara Vannucci, CLEAN-CUT coordinator at research@tesimag.com or cleancut@tesimag.com
1. the larger kerf caused by available diamond wire based on stainless steel strands (10 to 12 mm) when compared to 5 to 6 mm with steel blades;
2. the reduced life-cycle of the wire due to failures of the joints of the steel strands;
3. the lack of a proper control system able to constantly monitor anomalous stresses and deformations, thus guaranteeing the correct functioning of up to 50 wires singularly subject to different stresses because of the variable geometry of the block across the cutting plane.
To solve these bottlenecks, the CLEAN-CUT project has developed a cost-effective small diameter diamond wire with increased life cycle based on superelastic nichel-titanium alloys (nitinol). At first, the thermo-mechanical sequences and training procedures which are needed to obtain a superelastic nitinol wire with the required mechanical performances with respect to the specific application as well as with a stable mechanical behaviour along its whole life cycle and an improved fatigue behaviour were investigated, defined and optimised. In parallel, a proper control logic for process control was developed. Several cable designs were then considered based on the chosen alloy and a proper joining methodology for shape memory alloys (SMA-SMA) was suggested. Test bench characterisation of the mechanical and fatigue behaviour of the joint was also conducted. Integrated cutting wires with SMA core and with diamond beads with an external diameter of 7 mm were finally produced and tested on board of single-wire machines. Measurements were taken from the novel control system and recorded better performances in terms of fatigue resistance, damping behaviour and thus quality of the cut. Other advantages include easiness of manufacturing and suitability for cutting machines characterised by lower manufacturing and maintenance costs. The final solution of the cutting wire worked well in real working conditions, allowing good surface finishing and showing important perspectives that will be made concrete in the next industrialisation phase. The innovative design of the joint will allow to further decrease the diameter of the core and thus the bead diameter: in fact in this case there is not the need of a high number of thin wires that have to be threaded in order to make the joint, like for traditional strands. To do this new diamond beads have to be manufactured and tested and some significant changes have to be done on traditional machines, in order to make these ones adapt to be equipped with the new wires.
The participants to the project were:
1. Tesimag Srl: small and medium sized enterprise (SME) - Coordinator - Italy
2. Master Tre Srl (SME) - Italy
3. Mc Diam Sp z oo (SME) - Poland
4. Kohlhoff and Raatz GmbH (SME) - Germany
5. Centro di Progettazione, Design e Tecnologie dei Materiali - CETMA - Research and technological development (RTD) - Italy
6. Centre de Ricerca I Ivestigacio de Catalunya SA - CRIC (RTD) - Spain
7. Tevan Srl (RTD) - Italy.
Project objectives and the main public domain results are available on the project website, at the address http://www.project-cleancut.eu For further details and description, please contact Mrs Sara Vannucci, CLEAN-CUT coordinator at research@tesimag.com or cleancut@tesimag.com
