Diamond Wire Sawing Research Articles

Porous SiO2–Si3N4 Composite Ceramics Sintered by Carbothermal Nitridation of Diamond-Wire Sawing Silicon Waste

Porous SiO2–Si3N4 Composite Ceramics Sintered by Carbothermal Nitridation of Diamond-Wire Sawing Silicon Waste

Rock Mechanical Properties and Resource Potential of Dimensional Stone and Terrazzo in Tigray, Ethiopia: A Geological and Geomechanical Assessment

Dimension stone and terrazzo are quarried rocks following specific dimensions, generally huge in tonnage than ore minerals. Dimension stone and Terrazo resource development opportunities in the Tigray Region, Ethiopia, are studied regarding their potential to make dimension and terrazzo, geology and deposit nature, physio-mechanical properties, rock petrography, and opportunity for exploitation. The granite and marble are quarried as dimension stones and they meet the quality parameters of the rocks, which include, being durable, easy to quarry, work, cut, and polish. It was conducted through the integration of new geological descriptions, interpretation of thin sections, and physico-mechanical tests. Both surface and quarry rock samples were used for the study. 15 from granite and 15 from marble deposits in total 30 samples were used for petrographic analysis and physico-mechanical tests. Based on petrographic and physicomechanical results, granite is harder than marble this may be due to silicates being less dissolved than carbonates. The accessory minerals in both granite and marble deposits limit the quality of the deposits as being impurities. The integrated results indicate that the marble and granite deposits in the area are good in quality and quantity. In addition, they are geologically widespread, technologically do not need sophisticated technology and economically they do not need huge investment and have less effect upon the environment. Diamond wire saws and diamond belt saws separated the dimension stone, which are oblate to curved in shape with 1m width. In the area, investment has been at a relatively low stage more investment will significantly increase production of the dimension stone for local usage, export, and economic growth of the region.

A novel subsurface damage model in diamond wire sawing of silicon wafers

The subsurface damages (SSDs) generated during fixed abrasive diamond wire sawing (DWS) of silicon wafers can reduce the fracture strength and increase the breakage probability of these wafers. It is crucial to accurately evaluate these SSDs. A theoretical model of SSD depth is developed for the fixed abrasive DWS of silicon wafers considering the size effects of material properties, micro-geometries of abrasive grits, and inclination/interaction effects of subsurface cracks. A series of silicon wafers are processed, and the silicon material properties, diamond wire parameters, and surface/subsurface morphologies of silicon wafers are measured. The model is experimentally validated and then used to study the effects of processing parameters on inclination/interaction effects, cutting behaviors, and SSDs. The results show that the model has a relative error of less than 5.0% after revealing that the inclination/interaction parameters, cutting behavior parameters, and SSD depth almost follow a normal distribution, with a maximum distribution probability ranging from 30% to 50%. The average inclination angle is approximately 30°, the average cutting depth is in the range of one to two hundred micrometers, the average load is a few millinewtons, and the SSD depth is in the range of a few micrometers. With an increasing density of abrasive grit, a decreasing feed rate, or an increasing wire speed, the interaction effect becomes more pronounced, while the inclination angle, cutting depth, load, active grit ratio, and SSD depth decrease. When the protrusion height increases, or the half sharpness angle or tip radius of abrasive grit decreases, there is an increase in the cutting depth, load, active grit ratio, or SSD depth. The inclination angle decreases as the protrusion height, half sharpness angle, or tip radius increases. This research helps to understand the cutting mechanism and evaluate the SSDs during the DWS of silicon wafers.

Analysis of contact length and temperature effect in rocking mode diamond wire sawing of monocrystalline silicon carbide wafer

Diamond wire sawing (DWS) is a primary and fundamental stage for slicing large-diameter ingots into multiple wafers, enabling high-volume production in a single process. However, the extended contact length between the diamond wire and work material generates heat, which detrimentally impacts the surface quality of the sliced wafers and accelerates the diamond wire wear rate. This study implemented a rocking mode sawing strategy to investigate the effect of contact length on the surface quality of as-sawn wafer and diamond wire wear rate. Experiments have been conducted on monocrystalline silicon carbide (4H-SiC) with and without a rocking-mode multi-DWS machine. The experimental sawing temperature has been validated using Fourier’s law of thermal conduction, a finite element model, and a linear time series regression model. Results indicated that the minimal sawing temperature had been observed with the rocking mode sawing strategy, attributed to its shorter contact length compared to the process without rocking mode. Additionally, the finite element and regression models closely matched the experimental data, achieving accuracies of 93.57 % and 99.96 %, respectively. Fourier’s law of thermal conduction proved significant for precisely determining the sawing temperature. Notably, the rocking mode sawing strategy significantly affected the sawing temperature, surface quality, and diamond wire wear rate compared with the sawing process without the rocking mode.

Simultaneous preparation of high-purity Si and eutectic Si-Nd alloy utilizing Nd2O3-containing waste slag and diamond-wire sawing silicon waste

Nd2O3-containing waste slag (NCWS) and diamond-wire sawing silicon waste (DSSW) are important rare earth and Si secondary resources, respectively. Currently, NCWS and DSSW are recycled respectively by at least two different routes, which is not efficient and increases the burden on the environment. The present study proposed a novel technical route for preparing high-purity bulk Si and eutectic Si-Nd alloy simultaneously using NCWS and DSSW as raw materials, depending on the concept of using waste to treat waste. The new technical route has only two steps: initially, raw Si-Nd alloys were obtained by extracting Nd from NCWS utilizing DSSW as a low-cost reductant, and the impurity, oxygen, in the DSSW was effectively removed utilizing NCWS; the highest extraction rate of Nd from NCWS reached 68.3%, and the oxygen removal rate in DSSW was 99.89%; in the subsequent step, the obtained raw Si-Nd alloys were separated and purified to produce high-purity bulk Si (＞99.98%) and eutectic Si-Nd alloy (＞99%) through a physical and clean method-electromagnetic directional crystallization. This novel route is considered effective and environmentally-friendly for the sustainability of rare earth and Si resources, because no gas and liquid wastes discharged throughout the whole route, and two high value products can be prepared simultaneously using two wastes.

Optimizing the diamond wire sawing of polycrystalline silicon: An experimental approach

This study aims to determine the optimized cutting conditions for diamond wire sawing of polycrystalline silicon (poly-Si) wafers using a laboratory machine-tool that employs continuous cutting movement and reach cutting conditions similar to those in the industry. The experimental cutting was carried out following a central composite design, varying the wire cutting speed (vc) and feed rate (vf). A response surface methodology was employed to find the optimized cutting conditions for minimum surface roughness and subsurface micro-crack depth of the as-sawn poly-Si wafer. The results showed that the as-sawn poly-Si exhibited ductile scratches and fragile fractures in its surface morphology, with high vc and low vf resulting in a smooth surface. The response surfaces indicated that increasing vf led to increased Ra and Rq values, while increasing vc reduced them. Median micro-cracks were slightly inclined in the subsurface region, with the response surface indicating that their depth reduced with increasing vc and decreasing vf. The vf/vc ratio significantly affected surface integrity, with a lower vf/vc ratio being more suitable for reaching a smoother surface and shallower subsurface damage. The following material removal mechanisms was identified: optimal ductile region, ductile-to-brittle transition, brittle-ductile mixture region, and brittle region. Simulations using the response surface models indicated minimum values of Ra = 0.35 μm, Rq = 0.48 μm and SSD = 3.29 μm. Thus, this study provides a processing parameter window for diamond wire sawing of poly-Si wafers, which could be useful for both the photovoltaic and microelectronic industries.

Improvement of wire marks on the surface of Si3N4 ceramics cut by diamond wire saw

The presence of wavy wire marks on the cut surface of silicon nitride (Si3N4) ceramics reduces the mechanical properties of the slices and increases the workload of subsequent grinding and polishing processes. To improve the wire marks, a workpiece reciprocating movement-assisted diamond wire sawing (RMA-DWS) technology is proposed in this paper. While diamond wire sawing the Si3N4 ceramics, the workpiece is moved back and forth in the direction of the saw wire movement to assist in sawing. Single factor and orthogonal experiments were carried out to analyze the characteristics of the surface created by this sawing technology. The effects of workpiece reciprocating movement distance, workpiece reciprocating movement speed, saw wire speed and feed speed on the sawn surface morphology, surface roughness Ra and wire marks PV value, as well as the primary and secondary relationships of the effects, were investigated. And the optimal parameter combinations were explored. The results show that within the range of process parameters studied in this paper, the surface morphology of Si3N4 ceramics slices shows a comprehensive effect of material ductility and brittleness removal, the RMA-DWS technology can improve wire marks on the slice surface. Surface wire marks PV value can be reduced by increasing the workpiece reciprocating movement distance and saw wire speed, reducing the feed speed, while increasing the reciprocating movement speed of the workpiece, the PV value shows a trend of first decreasing and then increasing. The variation amplitude of surface roughness Ra value is not significant, and the variation trend is roughly similar to the change trend of PV value. It was determined that the experiment with the process parameters combination of 0.1 m/min feed speed, 90 mm workpiece reciprocating distance, 15 mm/s workpiece reciprocating speed and 1400 m/min saw wire speed yielded the optimal result, significantly improving the wire marks of the sliced surface. The results of this paper provide ideas for the development of sawing wire marks improvement technology.

Negative effect of lanthanum tungstate on the mechanical properties of W-La2O3 alloys

With the rapid development of the photovoltaic industry, tungsten alloys have been selected to replace the high‑carbon steel to fabricate the busbars for diamond wire saws due to their superior mechanical properties, and the La2O3 doped tungsten alloy has been widely used. However, the yield of eligible W alloy wires is not very high due to serious wire breakage problems during the production process, especially in the solid-liquid mixing route. To discover the possible reason, the commonly produced lanthanum tungstate (La30W17O96) in the solid-liquid mixing route has been systematically studied in the work, and its possible influence on the mechanical properties is also explored. It is found that the La30W17O96 leads to the formation of brittle second phases at grain boundaries (GBs), which weakens the intergranular bonding, resulting in a significant decrease in the compressive strength of tungsten alloys, manifested as intergranular fracture. Transmission electron microscopy (TEM) analysis reveals that these second phases are consisted of polycrystalline La6W2O15, La2W3O12 and amorphous states, and the La30W17O96 can decompose into a more stable structure during sintering. This work highlights the destructive effect of La30W17O96 on the intrinsic properties of tungsten alloys and provides a new perspective for solving the problem of tungsten wire breakage.

Material Removal Mechanisms of Polycrystalline Silicon Carbide Ceramic Cut by a Diamond Wire Saw.

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 (Ra) 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.

Effect of anisotropy on 4H-SiC cracking behavior during diamond wire sawing

Cracking behavior caused by the anisotropy of single-crystal silicon carbide (SiC) brings challenges to the quality of the diamond wire sawing and grinding process. In this study, the effects of SiC anisotropy on machanical properties is analyzed based on Griffith’s theory. The results indicate that the fracture toughness and the fracture strength exhibit anisotropy. At the same time, an analytical model for the initiation and deflection of the surface radial crack is proposed based on the scratching stress field. On the basis of these results, the anisotropic machanism of the surface radial crack initiation, deflection, the surface radial crack initiation (SRCI) depth, and the residual scratching depth are investigated in combination with the single abrasive scratching experiment. The shear stress and the maximum principal stress are the primary driving forces for the initiation and deflection of surface radial crack, respectively. The direction of the minimum shear strength and the fracture strength determines the anisotropy of cracking behavior. Meanwhile, the anisotropy of the SRCI depth and the residual scratching depth is caused by the fracture strength anisotropy. This research offers fundamental insights into the anisotropic cracking behavior of SiC, thereby contributing to the precise control of crack damage and improve the quality of the SiC diamond wire sawing and the as-cut wafers grinding process.

A Systematic Review of Modeling and Simulation for Precision Diamond Wire Sawing of Monocrystalline Silicon.

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.

Diamond wire saw forming cutting simulation analysis of arc workpieces

Abstract The application of diamond wire saws in the field of cutting hard and brittle materials is becoming increasingly widespread, especially in the photovoltaic industry where the demand for slicing processes for monocrystalline and polycrystalline silicon is continuously growing. Among these, the craftsmanship involved in arc-shaped workpieces is particularly complex. To analyze the impact of diamond wire saw processes on arc-shaped workpieces, PFC discrete element simulation software was utilized, aiming to produce a 1/8 arc segment, and the influence of the wire saw’s linear speed on the process was analyzed. The simulation results indicate that an increase in linear speed leads to improved particle distribution and a shape more closely resembling a circular form. However, the cutting process with a diamond wire saw must be controlled at an appropriate operating speed. If the speed is too high, it may lead to the destruction of the workpiece.

Ti-coated diamond micro-powder for the manufacture of the electroplated diamond wire saw

The electroplated diamond wire saw has been widely used in the production of semiconductors, photovoltaic devices, etc. Composite electroplating is an important process in the production of electroplated diamond wire saws. The utilization of nickel (Ni)-coated diamonds is a widely adopted approach to enhance the efficiency of the composite electroplating process employed in the manufacturing of wire saws. However, the pristine diamond does not chemically react with Ni, and the interfacial bonding strength between the Ni coating and the diamond is relatively weak. This frequently results in the detachment of diamonds from the Ni coating during the cutting process. To solve this problem, titanium (Ti)-coated diamonds were used in the preparation of wire saws. We had specially developed a vacuum slow evaporation technology to produce diamond micro-powder (8 μm) with uniform conductive Ti coatings that were firmly bonded with diamond through the interfacial product TiC. A series of electrochemical test results were used to demonstrate the effect of Ti coating on the composite electroplating process. The linear scanning voltammetry curves showed that the addition of Ti-coated diamond shifted the overpotential of composite electroplating in a positive direction, so it promoted the electrodeposition reaction more than diamond powder. The electrochemical impedance spectroscopy revealed that the conductive Ti-coated diamond reduced the charge transfer resistance during composite electroplating. The Ti-coated diamond micro-powder was completely enveloped by an electroplated Ni layer, and TiC formed between the Ti coating and the diamond provided a stronger interfacial bonding force compared to that of the Ni-coated diamond micro-powder. After cutting, the Ti-coated diamond was found not to fall off the wire saw. The use of Ti-coated diamond micro-powder as an abrasive will significantly improve the product quality of mass-produced electroplating diamond wire saws.

Fabrication of Ceramic Microchannels with Periodic Corrugated Microstructures as Catalyst Support for Hydrogen Production via Diamond Wire Sawing.

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.

Efficient manufacture of high-performance electroplated diamond wires utilizing Cr-coated diamond micro-powder

The slicing of silicon ingots using electroplated diamond wires is a fundamental process in the creation of semiconductor devices such as chips and photovoltaic cells. Composite electroplating, a process that uses nickel (Ni) plating to fix diamond particles onto a steel wire, is a critical step in the manufacturing of these diamond wires. In this work, chromium (Cr)-coated diamond was used to achieve rapid and high-quality composite electroplating, thereby aiding the production of high-performance diamond wire saws. The Cr-coated diamond micro-powder was prepared utilizing vacuum slow evaporation technology at a temperature of 850 °C. This resulted in a uniform and firm Cr coating that was firmly bonded to the diamond surface via Cr3C2. Subsequent electrochemical tests were conducted in the composite electroplating bath. Linear scanning voltammetric curves revealed that the Cr-coated diamond was capable of inducing a more positive shift in the overpotential of Ni deposition, thus enhancing the reaction beyond that of uncoated diamond micro-powder. Additionally, the electrochemical impedance spectra indicated a decrease in charge transfer resistance during composite electroplating, attributable to the conductivity of the Cr-coated diamond. Electroplated diamond wires incorporating Cr-coated diamond demonstrated a greater abrasive density per unit length. SEM results showed that Ni was able to deposit on the Cr-coated diamond surface, resulting in the abrasives being completely covered by the Ni plating. The Cr-coated diamond wire exhibits a stronger resistance to abrasive detachment after cutting, which could increase the diamond-protrusion of the wire. The utilization of Cr-coated diamond micro-powder as an abrasive is anticipated to enhance the manufacturing efficiency of diamond wires and improve product quality, thereby promoting advancements in hard and brittle material processing technology.

Mechanical model of diamond wire sawing for curved surfaces

Diamond wire sawing is effective in machining complex parts. During the wire-cutting process, the cutting force affects the wire causing different shape changes, thereby affecting the machining quality. This paper introduces a wire sawing mechanical model for curved surfaces that considers the interdependence between the spatial motion of the wire, cutting force, and material removal. A wire bow angle measurement system was built using spring displacement sensors, and the accuracy of the mechanical model was verified through curved surface cutting experiments. The mechanical model was used to analyze the influences of the machining parameters and twist surface cutting process on the wire bow angle. The results showed that the sawing twisted surface increased the float amplitude of the wire bow angle. The wire feed rate at both ends varied with time owing to the wire twisting motion. The change in the wire feed rate at both ends was the primary factor affecting the change in the wire bow angle during the twist surface-sawing process. When sawing twisted, curved surfaces, the wire bow angle gradually decreases with increasing preloading force and wire velocity and a decreasing workpiece feed rate. Increasing the wire velocity and decreasing the workpiece feed rate can reduce the float amplitude of the wire bow angle, thereby enhancing the stability of the cutting process. This study lays the theoretical groundwork for understanding wire deformation during curved surface sawing.

Enhancing Metal Impurity Removal in Diamond Wire-Sawing Silicon Kerf-Loss through Sonifier-Assisted Acid Leaching Process

Enhancing Metal Impurity Removal in Diamond Wire-Sawing Silicon Kerf-Loss through Sonifier-Assisted Acid Leaching Process

Wire Bow In Situ Measurement for Monitoring the Evolution of Sawing Capability of Diamond Wire Saw during Slicing Sapphire.

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.

Study on the effect of 1.4-butynediol on the performance of electroplated diamond wire saw

In response to the problems of low production efficiency and short service life of electroplated diamond wire saws used in the photovoltaic industry, in order to improve the performance of electroplated diamond wire saws, electroplating solutions with different mass fractions of 1.4-butynediol (0.1 g/L, 0.3 g/L, 0.5 g/L) were prepared by using electroplating methods. Nickel coatings were obtained through customized electroplating tanks, and electroplated diamond wire saws were prepared through electroplating processes. The effect of 1.4-butynediol content (mass fraction) in electroplating solution on the performance of diamond wire saws was studied. A scanning electron microscope was used to observe the microstructure of the coating surface and wire saw section, and the hardness, tensile strength, and wear of the coating with different concentrations of 1.4-butynediol were measured. The results show that among the three ratios, when the mass fraction of 1.4-butynediol is 0.3 g/L, the nickel coating has the best bonding with the metal matrix, the wire saw performance is the best, the coating hardness is the highest (427 MPa), and the wire saw has the least wear (0.092 g).

Experiment Comparative Analysis of Feed Rate with Velocity Control in Cutting Mono Crystalline Silicon Using a Diamond Wire Saw.

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.