Design And Research Of Fixed Abrasive Multi-wire Cutting Equipment

Fixed abrasive multi-wire cutting technology is widely applied in the field of hard and brittle material processing,owing to its high efficiency.With the rapid development of photovoltaic solar industry,it is possible to connect photovoltaic generation into distribution network with a low cost.Silicon is the core material in the photovoltaic industry,thus silicon wafer cutting is the required process to make full use of silicon materials.Thinner wire and thinner wafer are becoming a trend.However,the high rate of wire breakage in early equipment has reduced the quality of sliced silicon wafers,thus hinders the further development of photovoltaic industry.To meet the demand of slicing 160 ?m silicon wafer with 60 mesh diamond wire,it is essential to study the fixed abrasive multi-wire cutting mechanism and further design the structure of cutting equipment.It is significant to explore advanced fixed abrasive multi-wire cutting equipment,which will contribute to slice ultrathin silicon wafer with thin wire and thus to cut down the loss of silicon materials during slicing process.In addition,the fixed abrasive multi-wire cutting technology has a broad application prospect in domestic market.Developing advanced fixed abrasive multi-wire cutting equipment can break the monopoly of foreign companies in the wire-wire cutting industry.In the theoretical study of fixed abrasive multi-wire cutting mechanism and experimental study of the main factor in diamond wire slicing process,the key factors,such as wire span and speed,have been clarified.The reasons for the symmetrical layout in cutting equipment have been analyzed.Through modeling the framework of cutting equipment,the modal analysis has been carried out via Abaqus.The structure of cutting equipment has been optimized to reduce the interference between the inherent frequency of the equipment and the motor frequency.As a result,the inherent frequency of the equipment has been improved from 74.47 Hz to 265.88 Hz.The structures of large-size and small-size guide wheels have been designed by decentralizing their functions.The whole frame of the cutting equipment has been designed,in which the support span for diamond wire has been decreased to 280 mm by the small-size guide wheel.The function of guide wheel,as the key component in cutting equipment has been studied and is confirmed that it should be light-weight and low-inertia.By comparing different materials for guide wheels,models of large-size and small-size guide wheels were built via finite element analysis.As a result,a novel guide wheel with low-inertia of 0.96 kg.m2 has developed.It is revealed that the connection between bearing box and guide wheel should have high positioning accuracy and high stiffness.By theoretical finite element analysis,conical bearing bush with over-positioning properties has been developed.The cutting experiment indicates that the designed bearing bush can effectively improve the cutting yield by 0.8%.It has shown any sign of wear after 260 cuttings,thus the service life of which can be remarkably prolonged.By analysis of the mechanism and the stress on winding wheel,the wire machine and wire wheel have been developed.By observing the swing mode of arranging wire system,a novel wire machine has been designed,in which the swing center is located on the center of pulley groove.We comprehensively evaluated the tension loss on pulley groove,the economy of designed wiring machine,the bending radius and the n? mber of torsion rings of diamond wire,and then choosed the pulley groove with a diameter of 160 mm.As a result,the whole wire machine was designed.The slicing of 160 ?m silicon wafer by 60?m diamond wire demonstrated that the cutting yield can be higher than 94%.The sliced silicon wafer exhibits an excellent TTV performance.As a key parameter,its TTV value has a 95%confidence interval of mean between 11.14-11.29 ?m.The process capability index(PP)in wafer cutting has reached 1.64.The fixed abrasive multi-wire cutting equipment with high performance is the key in multi-wire cutting process.Under the demand of continuous cost reduction in photovoltaic solar industry,multi-wire cutting technology with ultrathin wire has a predictable prospect.In this paper,we studied the mechanism of fixed abrasive multi-wire cutting,and designed the novel large-size and small-size guide wheel with decentralized functions,to meet the demand of small-span cutting with ultrathin wire.We experimentally sliced 160 ?m silicon wafer with 60 ?m diamond wire and characterized the morphology of the sliced wafer by SEM.It is observed that the equipment has a good cutting quality.The sliced wafer has reached the anticipated quality requirement.By analyzing the process capability of the improved equipment,TTV,as a key parameter in slicing,has an average of 11.2 ?m,superior to 13.8 ?m in original equipment.Thereupon,the design strategy of the cutting equipment has been verified feasible and effective,which is of great significant in photovoltaic solar industry.