Search Results (36)

The surface quality of diamond wire sawing (DWS) wafers directly affects the efficiency and yield of subsequent processing steps. This paper investigates the motion trajectory of abrasives in ultrasonic-assisted diamond wire sawing (UADWS) and its mechanism for improving surface quality. The influence of ultrasonic vibration on the cutting arc length, cutting depth, and interference of multi-abrasive trajectories was analyzed through the establishment of an abrasive motion trajectory model. The ultrasonic vibration transforms the abrasive trajectory from linear to sinusoidal, thereby increasing the cutting arc length while reducing the cutting depth. A lower wire speed was found to be more conducive to exploiting the advantages of ultrasonic vibration. Furthermore, the intersecting interference of multi-abrasive trajectories contributes to enhanced surface quality. Experimental studies were conducted on monocrystalline silicon (mono-Si) to verify the effectiveness of ultrasonic vibration in improving surface morphology and reducing wire marks during the sawing process. The experimental results demonstrate that, compared with DWS, UADWS achieves a significantly lower surface roughness Ra and generates micro-pits. The ultrasonic vibration induces a micro-grinding effect on both peaks and valleys of wire marks, effectively reducing their peak–valley (PV) height. This study provides a theoretical basis for optimizing UADWS process parameters and holds significant implications for improving surface quality in mono-Si wafer slicing. Full article

This paper presents a study on optimising self-brazing powder mixtures for powder metallurgy diamond tools, specifically focusing on wire saws used in cutting natural stone. The research aimed to understand the relationship between the chemical composition of powder mixtures and the hardness of the sintered matrix. The experimental process involved the use of various commercially available powders, including carbonyl iron, carbonyl nickel, atomised bronze, atomised copper, and ferrophosphorus. The samples made of different powder mixtures were compacted and sintered and then characterised by dimensional change, density, porosity, and hardness. The obtained results were statistically analysed using an analysis of variance (ANOVA) tool to create linear regression models that relate the material properties to their chemical composition. The investigated materials exhibited excellent sintering behaviour and very low porosity, which are beneficial for diamond retention. Very good sinterability of powder mixtures can be achieved by tin bronze addition, which provides a sufficient content of the liquid phase and promotes the shrinkage during sintering. Statistical analysis revealed that hardness was primarily affected by phosphorous content, with nickel having a lesser but still significant impact. The statistical model can predict the hardness of the matrix based on its chemical composition. This model, with a determination coefficient of approximately 80%, can be valuable for developing new metal matrices for diamond-impregnated tools, particularly for wire saw beads production. Full article

Monocrystalline silicon is widely used in the semiconductor industry. During wafer machining with a diamond wire saw (DWS), a worn diamond wire can affect the slicing quality. To assess the effect of diamond wire wear on wafer machining, in this study, the impact of diamond wire wear on the wafer’s total thickness variation (TTV) and surface quality was examined at a wire velocity of 1.8 m/s and a feed rate of 0.5 mm/min. Through a single-factor experiment, the effects of the wire velocity, feed rate, and workpiece thickness on diamond wire wear were explored. The outcomes demonstrate that the wear rate was higher in the early and late wear periods, and the wafer machining quality was poor in these two periods. During the stable wear period, the machined wafer exhibited high quality, while the wear rate remained stable. Under the condition of machining the same area of the workpiece, with an increase in wire velocity, the wear quantity for the diamond wire was reduced. As the feed rate and workpiece thickness increased, the wear quantity of the diamond wire increased. The diamond wire wear remained roughly constant when the wire velocity and feed rate increased at the same ratio. Full article

Neodymium iron boron (NdFeB) magnetic materials are widely used in fields such as electronics, medical devices, power machinery, and hardware machinery. This paper conducted a three-factor and five-level orthogonal experiment on diamond wire saw cutting NdFeB to determine the influence degree of key factors such as workpiece feed rate, diamond wire speed, and workpiece processed size on the surface roughness Ra and waviness Wa of NdFeB slices. Further analysis was conducted on the influence of various parameters on the PV value (peak valley difference) of the waviness profile curve of the sawed surface. Finally, slicing processing was carried out under optimized process parameter combinations. The research results indicate that the primary and secondary order of process parameters affecting surface roughness Ra and waviness Wa is workpiece feed rate, wire speed, and sawed workpiece size, and the influence on the waviness PV value also shows a consistent trend. The optimal combination of processing parameters is workpiece feed rate of 0.1 mm·min⁻¹, wire speed of 1600 m·min⁻¹, and workpiece size of 10 mm. The obtained surface roughness Ra is 0.433 μm and the waviness Wa is 0.037 μm, respectively. The regression mathematical model for the waviness PV value is PV = 0.747 × v_s^−0.342 × v_w^0.546 × L^0.109. The research results of this paper provide an experimental basis and guidance for optimizing process parameters of sawing NdFeB. Full article

Wire sawing is an important process in the cutting of NdFeB magnets and the sawed surface topography and surface roughness (SR) are important indicators for assessing surface quality. This paper analyzed the effects of process parameters on the sawed NdFeB surface topography and SR based on orthogonal experiments and then presented an SR prediction model called ISSA-BP, which was based on a BP neural network using an improved sparrow search algorithm (ISSA). For the problem of insufficient optimization capability of the traditional sparrow search algorithm (SSA), Cubic chaotic mapping, Latin hypercube sampling, the sine–cosine algorithm, Levy flight, and Cauchy mutation were introduced to improve the traditional sparrow search algorithm (SSA) to obtain ISSA, improving algorithm convergence speed and global optimization. The ISSA was then used to optimize the initial weights and thresholds of the BP neural network for predicting Ra. Research shows that the sawed surface topography reflects a combination of brittle and ductile material removal. As the workpiece feed speed and size decrease and the wire speed increases, there is a reduction in SR. Compared with the SSA-BP and traditional BP models, the ISSA-BP prediction model has reduced various error indicators such as mean absolute error (MAE) and mean square error (MSE). The mean absolute error (MAE) of the prediction model optimized by the ISSA is 0.064475, the mean square error (MSE) is 0.0072297, the root mean square error (RMSE) is 0.085028, and the mean absolute percentage error (MAPE) is 3.7171%. The research results provide an experimental basis and technical support for predicting the SR and optimizing the process parameters in diamond wire-sawing NdFeB. Full article

Diamond-wire sawing silicon waste (DSSW) derived from the silicon wafer sawing process may lead to resource waste and environmental issues if not properly utilized. This paper propounds a simple technique aimed at enhancing the efficiency of hydrogen production from DSSW. The hydrolysis reaction is found to become faster when DSSW is ground. Among the studied grinding agents, KCl has the best performance. The grinding duration and addition amount remarkably affect the final hydrogen yield and initial hydrogen generation rate (IHGR). Among all studied samples, DSSW-KCl 25 wt% ground for 3 min shows the best performance with a hydrogen yield of 86.1% and an IHGR of 399.37 mL min⁻¹ (g DSSW)⁻¹ within 650 s. The initial temperature is also found to have a significant influence on the hydrolysis of the DSSW-KCl mixture, and the reaction can proceed to 85% conversion in 100 s with an IHGR of 1383.6 mL min⁻¹ (g DSSW)⁻¹ at 338 K. The apparent activation energy for the hydrolysis reaction of the DSSW-KCl composite powder was found to be 45.62 kJ mol⁻¹ by means of an Arrhenius plot. The rate-determining step for the rapid reaction of DSSW to produce hydrogen is chemical reaction control, while the slow reaction is controlled by diffusion. Full article

Diamond wire saw silicon slurry (DWSSS) is a waste resource produced during the process of solar-grade silicon wafer preparation with diamond wire sawing. The DWSSS contains 6N grade high-purity silicon and offers a promising resource for high-purity silicon recycling. The current process for silicon extraction recovery from DWSSS presents the disadvantages of lower recovery and secondary pollution. This study focuses on the original DWSSS as the target and proposes flotation for efficiently extracting silicon. The experimental results indicate that the maximal recovery of silicon reached 98.2% under the condition of a dodecylamine (DDA) dosage of 0.6 g·L⁻¹ and natural pH conditions within 24 min, and the flotation conforms to the first-order rate model. Moreover, the mechanism of the interface behavior between DWSSS and DDA revealed that DDA is adsorbed on the surface of silicon though adsorption, and the floatability of silicon is improved. The DFT calculation indicates that DDA can be spontaneously adsorbed with the silicon. The present study demonstrates that flotation is an efficient method for extracting silicon from DWSSS and provides an available option for silicon recovery. Full article

The demolishing of concrete structures such as bridges, tunnels, buildings, and pavements has become a common activity due to reasons such as renovation, rehabilitation, retrofitting, or simply ending the service life of these structures. This upsurge has brought major challenges in managing construction demolition waste (CDW). Traditional demolition techniques are often characterized by high environmental impacts, inefficiency in waste management, and safety concerns. This paper critically reviews traditional and emerging concrete structure demolition technologies in terms of efficiency, safety, environmental impact, waste minimization, and material recyclability. A detailed review of manual demolition, mechanical demolition, implosion, and relatively new techniques such as static blasting, diamond wire sawing, soundless chemical demolition agents, hydro demolition, electrical discharge technology, demolition robots, and microwave heating is conducted. The key findings of this paper are that various alternative technologies have significant advantages over their traditional counterparts by offering minimum environmental pollution, improvements in on-site safety, and a possibility for materials to be reused and recycled. For instance, hydro demolition and diamond wire sawing are very efficient and accurate, meaning that actual waste management is highly improved. This paper underlines that the choice of demolition methods adapted to project needs is crucial for the development of sustainable CDW management. Such findings are useful to practitioners and policymakers who have to make fully informed decisions to promote environmental sustainability and resource conservation goals. Full article

The photovoltaic (PV) industry is developing rapidly to support energy transformation and emission reduction. In the whole PV industry chain, diamond wire saw silicon powder (DWSSP) waste is the most promising secondary resource for recycling high-purity silicon. DWSSP mainly contains metal impurities, and the treatment process based on hydrometallurgy can effectively remove metal impurities. The current DWSSP recovery process was divided into three categories: direct acid leaching, pyrometallurgy followed by acid leaching, and acid leaching followed by pyrometallurgy. This paper gives a comprehensive overview of these three purification processes from the aspects of impurity removal and recovery yield. The results suggest that acid leaching followed by pyrometallurgy is currently the most effective process for removing metal impurities from DWSSP. Moreover, this study underscores the potential for enhancing the purity of reclaimed silicon through the application of external field reinforcement, oxygen-regulated acid leaching, and surfactant-facilitated organic acid leaching and points out the development direction for promoting silicon recovery from DWSSP. Full article

During the diamond wire saw cutting process of sapphire crystals, warpage is one of the key parameters for evaluating wafer quality. Based on the thermoelasticity theory and diamond wire saw cutting theory, a finite element model for thermal analysis of diamond wire saw cutting sapphire crystals was established in this paper. The variation laws and internal connections of the temperature field and thermal deformation displacement field of the wafer during the sawing process were analyzed. A calculation and analysis model for the warpage of sapphire crystal wafer cut by wire saw was established based on the node thermal deformation displacement field of the wafer, and the rationality of the simulation results was verified through sawing experiments. This simulation calculation model constructs the mapping relationship between the process parameters of diamond wire sawing and the sapphire wafer warpage during sawing. The influence of wafer thickness, diamond wire speed, feed rate, diamond wire diameter, and tension on the warpage of the wafer was studied using the simulation model. The results indicate that the highest temperature occurs in the sawing area during cutting. The wafer thickness decreases and the warpage increases. The wafer warpage decreases with the increase of the diamond wire tension and diameter, and increases with the increase of diamond wire speed and feed rate. The research results provide a reference for understanding the variation of wafer warpage during sawing and optimizing sawing process parameters. Full article

Polycrystalline silicon carbide (SiC) is a highly valuable material with crucial applications across various industries. Despite its benefits, processing this brittle material efficiently and with high quality presents significant challenges. A thorough understanding of the mechanisms involved in processing and removing SiC is essential for optimizing its production. In this study, we investigated the sawing characteristics and material removal mechanisms of polycrystalline silicon carbide (SiC) ceramic using a diamond wire saw. Experiments were conducted with high wire speeds of 30 m/s and a maximum feed rate of 2.0 mm/min. The coarseness value (R_a) increased slightly with the feed rate. Changes in the diamond wire during the grinding process and their effects on the grinding surface were analyzed using scanning electron microscopy (SEM), laser confocal microscopy, and focused ion beam (FIB)-transmission electron microscopy (TEM). The findings provide insights into the grinding mechanisms. The presence of ductile grinding zones and brittle fracture areas on the ground surface reveals that external forces induce dislocation and amorphization within the grain structure, which are key factors in material removal during grinding. Full article

Precision processing of monocrystalline silicon presents significant challenges due to its unique crystal structure and chemical properties. Effective modeling and simulation are essential for advancing the understanding of the manufacturing process, optimizing design, and refining production parameters to enhance product quality and performance. This review provides a comprehensive analysis of the modeling and simulation techniques applied in the precision machining of monocrystalline silicon using diamond wire sawing. Firstly, the principles of mathematical analytical model, molecular dynamics, and finite element methods as they relate to monocrystalline silicon processing are outlined. Subsequently, the review explores how mathematical analytical models address force-related issues in this context. Molecular dynamics simulations provide valuable insights into atomic-scale processes, including subsurface damage and stress distribution. The finite element method is utilized to investigate temperature variations and abrasive wear during wire cutting. Furthermore, similarities, differences, and complementarities among these three modeling approaches are examined. Finally, future directions for applying these models to precision machining of monocrystalline silicon are discussed. Full article

Hydrogen energy is the clean energy with the most potential in the 21st century. The microchannel reactor for methanol steam reforming (MSR) is one of the effective ways to obtain hydrogen. Ceramic materials have the advantages of high temperature resistance, corrosion resistance, and high mechanical strength, and are ideal materials for preparing the catalyst support in microchannel reactors. However, the structure of ceramic materials is hard and brittle, and the feature size of microchannel is generally not more than 1 mm, which is difficult to process using traditional processing methods. Diamond wire saw processing technology is mainly used in the slicing of hard and brittle materials such as sapphire and silicon. In this paper, a microchannel with a periodic corrugated microstructure was fabricated on a ceramic plate using diamond wire sawing, and then as a catalyst support when used in a microreactor for MSR hydrogen production. The effects of wire speed and feed speed on the amplitude and period size of the periodic corrugated microstructure were studied using a single-factor experiment. The microchannel surface morphology was observed via SEM and a 3D confocal laser microscope under different processing parameters. The microchannel samples obtained under different processing parameters were supported by a multiple impregnation method. The loading strength of the catalyst was tested via a strong wind purge experiment. The experimental results show that the periodic corrugated microstructure can significantly enhance the load strength of the catalyst. The microchannel catalyst support with the periodic corrugated microstructure was put into the microreactor for a hydrogen production experiment, and a good hydrogen production effect was obtained. The experimental results have a positive guiding effect on promoting ceramic materials as the microchannel catalyst support for the development of hydrogen energy. Full article

Electroplated diamond wire sawing is widely used as a processing method to cut hard and brittle difficult-to-machine materials. Currently, obtaining the sawing capability of diamond wire saw through the wire bow is still difficult. In this paper, a method for calculating the sawing capability of diamond wire saw in real-time based on the wire bow is proposed. The influence of the renewed length per round trip, crystal orientation of sapphire, wire speed, and feed rate on the wire sawing capability has been revealed via slicing experiments. The results indicate that renewing the diamond wire saw, and reducing the wire speed and feed rate can delay the reduction in sawing capability. Furthermore, controlling the value of renewed length per round trip can make the diamond wire saw enter a stable cutting state, in which the capability of the wire saw no longer decreases. The sawing capability of diamond wire saw cutting in the A-plane of the sapphire is smaller than that of the C-plane, and a suitable feed rate or wire speed within the range of sawing parameters studied in this study can avoid a rapid decrease in the sawing capability of the wire saw during the cutting process. The knowledge obtained in this study provides a theoretical basis for monitoring the performance of the wire saw, and guidance for the wire cutting process in semiconductor manufacturing. In the future, it may even be possible to provide real-time performance parameters of diamond wire saw for the digital twin model of wire sawing. Full article

Fixed-diamond abrasive wire saw cutting is one of the most common methods for cutting hard and brittle materials. This process has unique advantages including a narrow kerf and the ability to use a relatively small cutting force. In the cutting process, controlling the main process parameters can improve the processing efficiency, obtaining a better processing surface roughness. This work designs the PI controller (Proportional–Integral controller) based on the reciprocating wire saw cutting process. The control objects are the workpiece feed rate and wire saw velocity, and the control objective is the normal cutting force. For the control trials, several reference values of various normal cutting forces were chosen. The effects of feed rate and saw velocity on the cutting surface finish and cutting time were investigated in this work using wire saw cutting analysis on a square monocrystalline silicon specimen. The results of this study showed that under a constant applied force of 2.5 N, the optimal feed rate of the diamond wire through the specimen could reduce cutting time by 42% while achieving a 60% improvement in the measured surface finish. Likewise, optimal control of the wire saw velocity could reduce cycle time by 18% with a 45% improvement in the surface finish. Consequently, the feed speed control is more effective than the wire saw velocity. Full article