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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. [ABSTRACT FROM AUTHOR]

In the diamond wire sawing (DWS), the wire bow provides cutting force, reflecting the cutting ability and the saw wire cutting state, which is one of the important issues that need to be paid attention to in industrial production. Selecting the appropriate wire bow in the sawing process can not only improve the surface quality of the wafers, but also reduce the probability of breakage. Therefore, the prediction of the wire bow is of great significance for improving the yield of the wafers and reducing the wear of the diamond wire. In this paper, the force analysis of the wire bow formed by the sawing process is carried out, and the relationship between the cutting force and the material removal rate is obtained from the microscopic abrasive scratching process. The wire bow prediction model of diamond wire sawing based on process parameters is founded, and the accuracy of the model is verified by experiments. The established model is used to analyze the influence of process parameters on the wire bow in the current solar photovoltaic silicon cell substrate cutting, which provides guiding significance for diamond wire sawing production. [ABSTRACT FROM AUTHOR]

This paper reports on new research that: characterizes the influence of regenerative lateral forces on the stability of metal circular sawing; describes the role of process damping in potentially stabilizing the sawing process; and investigates the role that distributed and lubricated guides play in a sawing process prone to regenerative instabilities. We model the saw as a rotating disc using the Von Kármán plate theory. Equations of motion are derived using the Hamilton’s principle. Guides are modelled as being distributed and properties of the fluid are modelled to be a function of the guide size and its placement relative to the saw. The regenerative and process damping effects are incorporated based on other similar models for milling processes. Our model-based analysis suggests that: regenerative instabilities are characterized by a growth in the real part of the eigenvalue of the system; clearance between the guide and the rotating saw and the guide’s circumferential placement with respect to the cutting zone both influence the severity and speed regions of instabilities; material being cut and changing cutting engagements do not significantly influence the region of instabilities; and that process damping can help stabilize an otherwise unstable process. Though models need to be validated, our observations can still instruct the design of stable guided metal sawing processes in industries. [ABSTRACT FROM AUTHOR]

Foam ceramics made from solid waste have recently attracted considerable interest because of their environmentally friendly and sustainable properties. This study examines the manufacturing of foam ceramics through the direct sintering of granite sawing dust. An orthogonal experimental design was employed to explore the impact of the foaming-agent content, sintering temperature, holding time, and moulding pressure on the characteristics of foam ceramics. The experimental and analytical results show that under the given conditions involving a foaming agent content of 0.8 wt%, a sintering temperature of 1200 °C, a holding time of 30 min and a moulding pressure of 5 MPa, the produced foam ceramics have excellent properties. These included a bulk density of 0.892 g/cm³, water absorption of 0.130 %, porosity of 59.67 %, high compressive strength of 10.721 MPa, and thermal conductivity of 0.247 W/(m·K). Analysis of the pore structure revealed that the samples had an evenly distributed and sealed pore structure, which effectively increased the porosity and bulk density. This study effectively demonstrates the viability of producing porous ceramics from granite sawing dust, presenting a green and economically sustainable method for waste management and the creation of high-functioning materials. These findings offer promising prospects for the greater implementation of granite waste in the construction sector. [ABSTRACT FROM AUTHOR]

In diamond wire saw cutting monocrystalline silicon (mono-Si), the material brittleness removal can cause microcrack damage in the subsurface of the as-sawn silicon wafer, which has a significant impact on the mechanical properties and subsequent processing steps of the wafers. In order to quickly and non-destructively obtain the subsurface microcrack damage depth (SSD) of as-sawn silicon wafers, this paper conducted research on the SSD prediction model for diamond wire saw cutting of mono-Si, and established the relationship between the SSD and the as-sawn surface roughness value (SR) by comprehensively considering the effect of tangential force and the influence of the elastic stress field and residual stress field below the abrasive on the propagation of median cracks. Furthermore, the theoretical relationship model between SR and SSD has been improved by adding a coefficient considering the influence of material ductile regime removal on SR values based on experiments sawing mono-Si along the (111) crystal plane, making the theoretical prediction value of SSD more accurate. The research results indicate that a decrease in wire speed and an increase in feed speed result in an increase in SR and SSD in silicon wafers. There is a non-linear increasing relationship between silicon wafer SSD and SR, with SSD = 21.179 Ra4/3. The larger the SR, the deeper the SSD, and the smaller the relative error of SSD between the theoretical predicted and experimental measurements. The research results provide a theoretical and experimental basis for predicting silicon wafer SSD in diamond wire sawing and optimizing the process. [ABSTRACT FROM AUTHOR]

Ceramic materials have good temperature and corrosion resistance, which is one of the ideal materials used in microchannel catalyst support for medium and high temperature catalytic reaction. Three-dimensional (3D) flow field structure is the most potential microchannel structure due to its high efficiency of mass and heat transfer. However, ceramic materials are hard and brittle, and the size of microchannel structures are small. It is a great challenge to construct a ceramic based microchannel catalyst support with a complex 3D flow field by traditional processing methods. In this paper, a 3D staggered flow field microchannel with the width of 450 μm and the depth of 1500 μm was designed and processed by diamond wire sawing. The mass and heat transfer properties of straight microchannel (SM), micro-column array (MA) and 3D staggered microchannel (3DSM) were compared by simulation. The effects of different windward angles (60°, 90° and 120°) on the performance of mass and heat transfer in 3D flow field were analyzed. The simulation results showed that the performance evaluation criteria (PEC) of 3DSM120° was 1.37, which meant better performance of heat and mass transfer than SM and MA. And the PEC of 3DSM structure was increased from 1.25 to 1.37 with the windward angle increasing from 60° to 120°. The pressure drop characteristics and hydrogen production performance of the microchannel catalyst support with different structures (SM, MA, 3DSM) were tested. The experimental results showed that the 3DSM had a good hydrogen production performance of methanol steam reforming (MSR) with the inlet flow rate of 1.5 ml/h at 300 °C. The methanol conversion rate was 99.43%, which was 15.41% and 6.20% higher than that of SM and MA, respectively, due to its better performance of mass and heat transfer. • A 3D staggered microchannel catalyst support with 3D flow field is designed and fabricated by diamond wire sawing. • The influences of 3D flow field structure on improving the heat and mass transfer performance are analyzed. • The PEC of 3D flow field structure is increased from 1 to 1.37, higher than other general flow field structure. • A methanol conversion of 99.43% is obtained by MSR microreactor with 3DSM120° structure at 300 °C, 1.5 ml/h feeding rate. [ABSTRACT FROM AUTHOR]

Sustainable manufacturing is essential to minimize energy consumption and environmental footprints. In the diamond wire sawing (DWS) process, minimizing energy consumption without compensating for the surface roughness of as-sawn wafer is crucial for achieving a cost-effective and environmentally friendly process. However, the evaluation and assessment of energy consumption without compromising the surface roughness of the as-sawn wafer in the DWS process have not been thoroughly studied. This study aims to investigate the correlation between energy consumption (EC), surface roughness (Ra), and material removal rate (MRR) of DWS to effectively reduce environmental footprints and simultaneously improve the surface quality of the as-sawn wafer during a single-wire DWS process. Experiments have been conducted on monocrystalline silicon (Si), incorporating various process parameters, namely wire speed, feed rate, and wire tension, as controllable factors. A mathematical relationship between the parameters has been formulated using the response surface methodology and optimized using a multi-objective particle swarm optimization (MOPSO). Results show that the optimum parameter combination is obtained at a wire speed of 0.36 m/s, a feed rate of 0.029 mm/min, and wire tension of 7 N and has reduced energy consumption, surface roughness, and MRR of 8.53%, 2.85%, and 4.86%, respectively, when compared to the traditional sawing process based on per wafer. Results of this study can be applied on the multi-wire DWS of Si wafer processing for achieving sustainable manufacturing practices. [ABSTRACT FROM AUTHOR]

Premiered in 2020, and although representing a grim story to narrate the Khashoggi story – a Saudi prominent journalist – who was ambushed, killed, and his body dismembered in his own country's consulate, The Dissident is more than simply a documentary. It is arguably a narration of the need for freedom of expression and political reform in the Arab world generally and Saudi Arabia in particular. This paper highlights the struggle to disseminate The Dissident documentary publicly as none of the major media corporation streamers (HBO, Netflix, Amazon, and Apple) offered to carry it. The way giant media corporations treat the information in this case not only as a commodity but as a means to avoid political tensions affecting their revenues in the markets. The article addresses this case study from a freedom of expression and the right to communicate perspective arguing for the need of an actual media reform within the middle east media system so journalists, like Khashoggi. [ABSTRACT FROM AUTHOR]

Finishing materials play an important role in architectural design. Since ancient times, claddings made of noble materials (mainly stone) convey grandeur. Clearly, there was a technology to transform quarry stones into slabs using stone sawing machines. An example of this comes from the excavation work carried out in 1930 at the Temple of Artemis in Jerash (6th century AD). The archaeologists found a facility which was classified as a stone sawmill. The efficiency of such machines, their construction method and their resistance characteristics have not been studied as yet. This paper aims to define such parameters for the stone sawing machine located in Jerash. [ABSTRACT FROM AUTHOR]

This study focused on the impact of the wood sawing pattern on 50 mm thick beech timber, followed by cross-cutting on the 3 m long, 50 x 50 mm beech blanks. The study analyzed two methods of cutting patterns of beech blanks (parallel to the surface of the timber and parallel to the grain fiber of the timber) regarding yield values and the size of longitudinal warping after air-drying. The yield values were higher (from 65.14 to 72.70 %) when producing long beech blanks using the method of sawing parallel to the timber's axis (B) compared to parallel to the edge of the blank (from 60.38 to 68.40 %). Results showed that a crucial factor for choosing the cutting method (A or B) is the taper of the logs. For blanks with a taper ≥ 1.3 cm.m-1, it is more advantageous in terms of longitudinal warping and yield to use the method of sawing parallel to the timber's axis. [ABSTRACT FROM AUTHOR]

Focused ultrasound-assisted diamond wire sawing (DWS) is proposed in order to improve the sawing performance in terms of sawing force, surface finish, and edge chippings. Under the streaming effect of acoustic wave, the diamond wire saw is forced to move at high frequency. The highest acoustic pressure is obtained at the focal point according to the distribution of scattered waves. A series of sawing experiments with focused ultrasound assistance are accomplished. The influence of wire speed and normal load on sawing forces and surface quality is studied. It is shown that the tangential forces decrease with the increase of wire saw speed. Sawing forces with focused ultrasound assistance are always smaller than that under the traditional condition with the same cutting parameters. Typically, a reduction of 56.0% can be obtained for friction factors. Under the effect of acoustic cavitation and streaming, burrs can be effectively removed from the cutting zone. Furthermore, high ductile removal region can be produced, resulting in better surface finish. During focused ultrasound-assisted DWS, only a few tiny edge chippings appear and a reduction of 56.6% in the maximum edge chip width is provided. Due to the cavitation and cleaning effects, less particles and agglomeration are found on the on the wire surface. [ABSTRACT FROM AUTHOR]

The present study is developed in the areas of the Los Palacios Agroindustrial Base Business Unit, with the objective of increasing the yield of Eucalyptus pellita F Muell, and Eucalyptus saligna Smith sawn wood from the use of a combination of treatments to reduce the effect of growth stresses and sawing schemes. 200 logs of 4 m were used and through the two-factor ANOVA analysis, it was found that there are no significant differences between the species on the Cracking Index; considering also that the best results are obtained in logs stored with irrigation for Eucalyptus saligna and standing ringed trees for both species. From the application of the elimination method in the linear regression analysis, the conicity variable is excluded for the construction of the prediction model using the diameter of the logs as the only independent variable in the two equations obtained, which are characterized by presenting high coefficients of correlation, determination and low standard errors of estimation. Taking into consideration the sawing methods, it is defined that the best yields of sawn wood are obtained from alternative tangential sawing combined with the treatment of standing ringed trees. [ABSTRACT FROM AUTHOR]

• A strategy for the Si recovery and Al removal from DWSSP was proposed. • The main impurity Al in DWSSP was derived from perlite filter aid. • The introduction of Na 2 CO 3 can create impurity-trapped LPS-layer on DWSSP. • The elimination mechanism of impurity Al from DWSSP-ceramic was studied. • The strategy has the potential for DWSSP utilization in the PV industry. Recycling diamond wire sawing silicon powders (DWSSP) from photovoltaic (PV) silicon wafers production has become an urgent problem. The challenge of recovery is the surface oxidation and contamination of the ultra-fine powder with impurities during the sawing and collection process. In this study, a clean recovery strategy of Na 2 CO 3 -assisted sintering and acid leaching was proposed. Due to the Al contamination from the perlite filter aid, the introduced Na 2 CO 3 sintering aid can react with the SiO 2 shell of DWSSP to form a slag phase with accumulated impurity Al during the pressure-less sintering process. Meanwhile, the evaporation of CO 2 contributed to the formation of ring-like pores surrounded by a slag phase, which can be easily removed by acid leaching. When 15 % Na 2 CO 3 was added, the content of impurity Al in DWSSP could be reduced to 0.07 ppm with a removal rate of 99.9 % after acid leaching. The mechanism suggested that the addition of Na 2 CO 3 can trigger the liquid phase sintering (LPS) process of the powders, and the cohesive force and liquid pressures difference generated during the process facilitated the transportation of impurity Al from the SiO 2 shell of DWSSP to the formed liquid slag phase. The efficient silicon recovery and impurity removal of this strategy demonstrated its potential for solid waste resource utilization in the PV industry. [ABSTRACT FROM AUTHOR]

As a typical hard and brittle material, gallium oxide crystal (β-Ga2O3) is easy to crack during processing. Diamond wire saw is the main way to produce β-Ga2O3 wafers. During the slicing process, a microcrack damage layer will be generated on the surface of the wafer. Under the stress, the microcracks will expand, leading to material breakage and fracture. In this paper, a finite element model of diamond wire sawing of β-Ga2O3 (010) crystal surface was established. The distribution of mechanical stress, thermal stress, and thermal-mechanical coupling stress during the sawing process were studied. The effects of sawing wire speed, feed speed and different parameter combinations under constant speed ratio on the thermal-mechanical coupling stress were analyzed. The research results show that: the thermal stress generated by sawing heat dominates the thermal-mechanical coupling stress during the sawing process; the mechanical stress caused by sawing force has a small numerical value and proportion, but it affects the distribution of thermal-mechanical coupling stress; increasing sawing wire speed and feed speed will increase the thermal-mechanical coupling stress. [ABSTRACT FROM AUTHOR]

Ultrasonic-assisted inner diameter machining is a slicing method for hard and brittle materials. During this process, the sawing force is the main factor affecting the workpiece surface quality and tool life. Therefore, based on indentation fracture mechanics, a theoretical model of the cutting force of an ultrasound-assisted inner diameter saw is established in this paper for surface quality improvement. The cutting experiment was carried out with alumina ceramics (99%) as an exemplar of hard and brittle material. A six-axis force sensor was used to measure the sawing force in the experiment. The correctness of the theoretical model was verified by comparing the theoretical modeling with the actual cutting force, and the influence of machining parameters on the normal sawing force was evaluated. The experimental results showed that the ultrasonic-assisted cutting force model based on the six-axis force sensor proposed in this paper was more accurate. Compared with the regular tetrahedral abrasive model, the mean value and variance of the proposed model's force prediction error were reduced by 5.08% and 2.56%. Furthermore, by using the proposed model, the sawing processing parameters could be updated to improve the slice surface quality from a roughness Sa value of 1.534 µm to 1.129 µm. The proposed model provides guidance for the selection of process parameters and can improve processing efficiency and quality in subsequent real-world production. [ABSTRACT FROM AUTHOR]

Diamond wire sawing (DWS) is often used to cut and slice crystalline silicon. The machining accuracy of DWS is a key performance of wire sawing. However, due to the inconsistent deformation of diamond wire relative to the workpiece in different sawing directions, the machining accuracy is different. In this paper, the machining accuracy of DWS in rip sawing and cross sawing was compared. Sawing tests were designed for rip sawing and cross sawing in different feed directions. The length of sawing kerf was used for the evaluation of machining accuracy. It was found that the machining accuracy of diamond wire pushing the workpiece (rip +) is obviously better than that of pulling the workpiece (rip −) in rip sawing as the wire stiffness of rip + is higher. The machining accuracy of cross sawing in different feed directions is related not only to wire stiffness, but also related to the wire torsion produced by lateral feed force in cross sawing. Therefore, the order of machining accuracy 1X + > 4Y − > 2Y + > 3X − shows that the cross sawing accuracy does not show an obvious law relative to rip sawing. A diamond wire electrical discharge sawing (DWEDS) was proposed in rip sawing and cross sawing to compare the machining accuracy of DWS. It was found that the machining accuracy of DWEDS is higher than that of DWS. No significant differences were found in machining accuracy between rip sawing and cross sawing in DWEDS. Finally, the characteristics of cutting force in time–frequency domain were analyzed. [ABSTRACT FROM AUTHOR]

Wire saw slicing technology has become a research hotspot in the field of slicing of brittle-and-hard materials. As an important process in semiconductor wafer processing, wire saw slicing has a crucial impact on the quality of semiconductor wafers. This paper introduces the basic theory and the research progress of wire saw slicing technology, taking the most mature silicon crystal as an example, especially the mechanical model and material removal mechanism of wire saw slicing. Then the influence of wire saw manufacturing technology and slicing process on the material is discussed. Furthermore, silicon carbide is a key material that supports the development of electric cars, clean energy and national defense industry because of its outstanding comprehensive advantages in physical properties, such as wider band gap. In this paper, the application and technological progress of wire saw slicing in silicon carbide wafer processing are reviewed. In addition, the influence of wire saw slicing on the surface quality and damage of silicon carbide crystal is analyzed. Finally, this paper points out the challenges and future development directions of wire saw slicing technology. [ABSTRACT FROM AUTHOR]

• A new method for recycling DWSSP was proposed. • Direct current, as an auxiliary means, was used to enhance impurity separation process. • Recycled silicon had a purity of near 5.5 N. As the unavoidable by-products in the production of solar cells, the recycling and reuse of diamond-wire sawing silicon powder (DWSSP) have always been a key issue in the solar energy industry. However, until now, there is no effective method to achieve effective recovery of high-purity silicon. In this work, a new method was proposed to achieve the recycling of DWSSP. Direct current, as an external means, was introduced into the recycling process of DWSSP, and its influence mechanism on impurity removal process was also discussed. By optimizing the local temperature gradient at the front of the Solid-Liquid interface, and the impurity diffusion behavior at the front of the interface was improved. After purification, the impurity content in the silicon ingot is reduced significantly. Among them, Al, as the main metal impurity element was reduced to less than 5ppmw (from 13580ppmw), and Ni (80.78ppmw), Fe (57.60ppmw), Ti (5.79ppmw), etc. decreased to less than 1ppmw. This work improved the purification efficiency of DWSSP, and put forward an optimized recycling method, which is expected to realize the direct reuse of DWSSP in the photovoltaic industry. [ABSTRACT FROM AUTHOR]

Diamond wire sawing is widely used in processing NdFeB rare earth permanent magnets. However, it induces periodic saw marks and fracture chipping pits, which severely affect the flatness and surface quality of the products. In this study, the lateral motion of the diamond wire was monitored to determine the surface formation mechanism. Then, a white light interferometer and an SEM were used to observe the sawed surface profile. Finally, the surface quality was quantitatively studied by identifying the area rate of fracture chipping pits with an image recognition MATLAB script. According to the observation results, the calculation formula of PV which is related to the process parameters was deduced. Additionally, by combining the fracture rate and wire vibration, a novel method was proposed to investigate the optimal process parameters. It can be found that the surface quality sawed at P = 0.21 MPa, vf = 0.2 mm/min, and vs = 1.8 m/s remains better than when sawed at P = 0.15 MPa, vf = 0.1 mm/min, and vs = 1.8 m/s, which means the sawing efficiency can be doubled under such circumstances, i.e., when the surface quality remains the same. [ABSTRACT FROM AUTHOR]

The machinability of materials is highly affected by their hardness, and it affects power consumption, cutting tool life as well as surface quality while machining the component. This work deals with machining of annealed AISI 4340 alloy steel using a coated carbide tool under a dry environment. The microhardness of annealed and non-annealed workpieces was compared and a significant reduction was found in the microhardness of annealed samples. Microstructure examination of the annealed sample revealed the formation of coarse pearlite which indicated a reduction of hardness and improved ductility. A commercially CVD multilayer (TiN/TiCN/Al2O3/ZrCN) coated cemented carbide cutting tool was employed for turning quenched and tempered structural AISI 4340 alloy steel by varying machining speed, rate of feed, and depth of cut to evaluate the surface quality, machining forces, flank wear, and chip morphology. According to the findings of experiments, the feed rate possesses a high impact on surface finish, followed by cutting speed. The prominent shape of the serrated saw tooth chip was noticed at a higher cutting speed. Machined surface finish and cutting forces during turning is a function of the wear profile of the coated carbide insert. This study proves that annealing is a low-cost and economical process to enhance the machinability of alloy steel. [ABSTRACT FROM AUTHOR]

The sawing of Hymenaea courbaril is complex due to its high density and abrasiveness. These factors accelerate the wear on saw blade teeth, and as a consequence, increase the cutting variability and process costs. The effect of cutting parameters on standard deviation of sawn-wood thickness was evaluated to propose optimal sawing conditions. A log carriage bandsaw with two saw blade geometries, three log diameter classes, and two feed rates were used to carry out the sawing tests. The results showed that the sawing variation expressed by the total standard deviation of board thickness was lower than 1 mm, when log diameter was lower than 0.79 m, and the log carriage feed rate was lower than or equal to 10 m min-1 for both saw geometries. The sawing thickness was affected by log diameter and log carriage feed rate, while saw geometry was not statistically significant. However, the goal of this initiative was not an estimation of the changes on sawmill productivity. Before this study, all log classes were processed with a log carriage feed rate of no higher than 10 m min-1. Consequently, given the estimated total standard deviations, it can be suggested that the logs of class 2 could be sawn at a 50 % higher rate without altering the cutting precision, improving sawmill productivity. [ABSTRACT FROM AUTHOR]

Sawing by circular saw blades is predominant in the mechanized treatment of natural stone. The predictive sawing force is crucial for optimizing, controlling, and monitoring the sawing process. In this work, a novel model for predicting sawing force, which is based on the distribution of the undeformed chip thickness at the sawing contact arc, was proposed. Based on the analysis of the undeformed chip geometry of the circular saw blade, the segment surface was divided into the front end and rear end according to the contact pattern between the segments and granite, and the models of the maximum undeformed chip thickness of diamond particles on the front end and rear end were established. Results showed that the new proposed force model fully considered the distribution of undeformed chips compared with the current model. The novel model has higher prediction accuracy, the mean maximum absolute error is within 3.77%, and the maximum absolute error is within 7.83%. Through theoretical analysis, the ratio of the maximum undeformed chip thickness of the front segment to the rear segment is 1.67, which can fully explain the wear non-uniformity of the segment. The proposed model is of great significance to the optimization of the saw blade structure and process parameters. [ABSTRACT FROM AUTHOR]

The effects of the Engineered Micro-Geometry (EMG) of the carbide teeth of circular saws on their wear rate and resulting sawing variation for 2-time intervals were studied. The objective was to improve the wear resistance of circular saws used during the primary transformation of wood. The tests were carried out under industrial production conditions with two series of circular saws; 1-with up-sharp tips, and 2-with cutting edges honed to adopt a waterfall geometry. The duration of the tests was 255 min and 645 min. Wood studs were sampled to measure sawing variation. Recession on the rake and clearance faces of the tips as well as the width of the wear land were measured. The wear mechanisms of the cutting edges of both types of saws were studied. Chipping and cracking were the two dominant wear mechanisms observed on the up-sharp tips. Saws with waterfall hone tips showed remarkably reduced chipping and cracking. Wear rate of the latter was notably lower than that of saws with up-sharp tips at both periods of sawing. Between-stud, within-stud, and total sawing variations decreased when saws with modified cutting edges were used. [ABSTRACT FROM AUTHOR]

Ceramic is an ideal material for preparing micro-channel catalyst supports with their characteristics of high temperature resistance, corrosion resistance and mechanical strength. High aspect ratio micro-channel structure has the advantages of large specific surface area, strong mass and heat transfer performance and high material utilization. However, ceramic materials are hard and brittle, and it is difficult to fabricate micro-channel structures with aspect ratio more than 1.5:1 by traditional processing methods. In this paper, a cutting method of large diameter diamond wire sawing was proposed. The micro-channels with width of 520 μm and aspect ratio of more than 4:1 was successfully fabricated by this method. Furthermore, the integrity of the micro-channel structure processed by diamond wire sawing was analyzed. And than the effect of surface morphology in different processing parameters on the catalyst loading performance were studied. The catalyst loading strength of ceramic slices with different surface morphology was tested. Finally, the ceramic micro-channel array was used as the catalyst support in micro-reactor for hydrogen production via methanol steam reforming (MSR). The methanol conversion rate and H 2 production rate could reach 87.8% and 74.6 mmol/h, respectively under GHSV 12600 ml/g·h at 300 °C. The experimental results show that the large-diameter diamond wire sawing technology can be used to process ceramic microchannels with high aspect ratio; using ceramic microchannel arrays as catalyst supports in hydrogen production can obtain better reaction performance; the feasibility of ceramic materials were broadened as microchannel catalyst supports. • The large diameter diamond wire sawing technique was proposed to fabricate high aspect ratio ceramic-based microchannel array. • Influences of surface morphology on catalyst loading performance were analyzed. • Ceramic-based microchannel array was used in methanol steam reforming reaction for hydrogen production and better performance was obtained. [ABSTRACT FROM AUTHOR]

The design of structural elements, the design of connections and supports, and damage have a significant influence on the technical characteristics of wood construction projects. An innovative experimental study was carried on locally obtained glulam beams. This study aimed to evaluate the load-bearing capacity of a finger-jointed Terminalia Superba (fraké) lamellae during routine use of an adhesive in the local area and to improve the connections in glulam structures. The achievement of this objective will allow to determine the influence of the technical characteristics of finger-jointing on the mechanical resistance, to maximize the mechanical resistance of the reconstituted beams, and eventually to minimize the losses due to sawing. All this will have a considerable impact on the technical and economic aspects of a wood construction project. The physical aspect of the species was studied and properties found. The influence of variation in density, the bonding surface, and joint efficiency on the bending strength (MOR) of Terminalia Superba (fraké) was studied. Mechanical properties were found and related to the optimum joint angle α, and the breaking point reads 0.20 mm. For the angular range of [0°–30°], adhesive failures are witnessed, and beyond this range, the failures are mixed. The 45° finger-jointing angle appeared to be better in the axial traction mode of rupture. [ABSTRACT FROM AUTHOR]

In their recent paper, Parnia and colleagues propose a new label for the near‐death experience (NDE): recalled experience of death. They claimed NDEs are "authentic" only when an objective danger is present and that authentic NDEs have a proven core phenomenology. We consider that these claims are insufficiently supported by empirical data. NDEs appear as a continuum of heterogeneous experiences of consciousness precipitated by the disjunction of processes usually combined in normal mental activity. The "core phenomenology" of NDEs is also opened to several criticisms. Closeness to "real" death does not appear to be a decisive criterion for characterizing NDEs. The author's adhesion to Raymond Moody's NDE model produces a biased partition of this field of research that is unable to provide the basis for a consensus. [ABSTRACT FROM AUTHOR]

For a long time, there has been a significant vacuum in the supply of lumber in China. In order to alleviate the contradiction between wood supply and demand and to increase the outturn rate of wood products blank. This study employs pine sawn timber as the research object and uses the dimensional specifications and defect conditions measured in the field to construct a sawn timber register. According to the measured data, the experimental scheme of regression analysis was designed and the simulated sawing experiment of pine sawn timber was completed. The regression equation of the outturn rate about basic blank and short blank was established by regression analysis for experiment results and the law of the impact of the factors on output indicators was determined. The results showed that the quality of sawn timber and the requirement for the quality of blank were the most important factors affecting the outturn rate of wood products blank. With the improvement of the quality of sawn timber and the decrease of the quality requirement for the quality of blank, the outturn rate of total blank will increase by more than 12%. A new idea of using the relative area of sawing surface defects to divide the sawn timber grades was proposed, and the corresponding relationship between the sawn timber grades and the production process of high-quality blanks was established, which provided basic theoretical support for optimizing the development of sawing equipment. [ABSTRACT FROM AUTHOR]

The quality of sawn wood is affected by the warping that it presents after drying, it is important then, to understand the mechanisms that regulate this deformation. Consequently, this work offers results of the influence of the variation and sawing patterns, dimensions and drying time of the pieces, on the warping of the sawn wood of Pinus caribaea var caribaea. The sawn pieces come from trees of the same origin, diameter and age. The study of the sawing variation was carried out with a methodology similar to that proposed Center of Forestry Studies, samples were taken with the same length and width but, of different thickness to every third of the selected piece. For the analysis of sawing schemes, sawn pieces were used taking into account the position of the medulla on the face, edge and center of the piece and pieces that do not contain it. The influence of the dimensions, were studied from taking pieces in different positions in radial direction with different dimensions (13 x100x3000) mm and (75x100x3000) mm were coded as: A, B and C by the distance to the medulla. Warpage measurements were made at 25, 60 and 90 days of drying. According to simple analysis of variance, the sawn pieces that experience less warpage are those that not contain medulla, those that do not experience variations in sawing, and those with greater thickness. Warping increases with drying time. [ABSTRACT FROM AUTHOR]

The focus of this study is the examination of tool wear or the causes of tool radius increase, during sawing of melamine wood panels with CNC machines. During the tests, the following materials will be used: laminated particleboard, based on the objectives of the study, for the technological sawing operation, with dimensions 2100x2800x18mm, first quality. As a cutting tool for sawing it is used the one in the shape of a disc, as in figure 4. Table 1, presents all the details of the cutting instrument, its geometry, the blade angle, the number of rotations, its material of construction etc. The examination of tool wear was measured by the direct measurement method, with the help of a measuring device called Nikon NEXIV VMR-3020 CNC Video Measuring System, with the possibility of lensing up to 270 times. While the data obtained from the measurement are presented in table no. 2, constructing an overview of the data, from the results obtained. This data was also compared by mathematical calculations, with a clear difference in consumption, between the initial radius and that after t working minutes. From all this, a mathematical model is obtained, which serves the users to choose the right instrument for the respective wood-based material, in this case carpentry boards, for the technological operation of sawing. [ABSTRACT FROM AUTHOR]

In reciprocating diamond wire sawing of quartz glass, the reversing and acceleration and deceleration will cause the position change of diamond wire, resulting in the discontinuous wire sawing in the reversing stage, so as to leave residual material on the processing surface and form wire marks. Also, the cutting load will cause diamond wire deformation as bow shape, and affect the machining accuracy. In this paper, the evaluation of DWS machining performance of quartz glass focus on the sawing time, cutting force and vibration, wire tension, machining surface flatness and roughness, surface morphology and wire state. The theoretical analysis of wire mark was carried out, and the simplified wire bow model of quartz glass sawing was established. The existence of wire mark and wire bow were verified by detecting the 3D contour of the slice. In addition, a diamond wire electrical discharge sawing (DWEDS) was performed to find the differences to DWS in the above indicators. Experiments were presented in jet cooling and bath cooling conditions. It was found that the cutting force, vibration, and wire tension of DWEDS are more stable than that of DWS. The DWEDS has been proved helpful to improve machining performance of quartz glass from surface roughness, sawing time, processing state, and wire bow control as it reduces the macro cutting force acting on the diamond wire although the discharge effect is weak. The SEM of slice surface and diamond wire showed no significant difference between DWEDS and DWS. Also, the influence of feed speed and cooling methods on machining performance was investigated. [ABSTRACT FROM AUTHOR]

The damages of silicon wafer in diamond wire sawing have a significant impact on its mechanics, economy, and use properties, which should be evaluated accurately and quickly. A theoretical model is developed to determine the surface roughness R z (ten-point mean height) and subsurface damage (SSD) depth by the fracture width of silicon wafer. The model takes into account the scratch groove direction and material pile-up effect of silicon wafer. A digital image processing method is integrated into the model to extract the fracture parameters of silicon wafer. Many silicon wafers are processed under different slicing parameters, for which the fracture parameters and surface roughness R z are measured by confocal microscopy, and the SSD depth is measured with the method of cross-section scanning microscopy. The scratch-induced material pile-up height is evaluated by nanoscratching. The calculated and measured fracture parameters, surface roughness R z , and SSD depth are analyzed by contrast. The result shows that the model can accurately and quickly determine the surface roughness R z and SSD depth with an average relative error of less than 12.0% in 20 s. The distribution characteristics of fractures, surface roughness, and SSD are analyzed. The result shows that more fractures have relatively smaller fracture width, depth, length, or related SSD depth. The image-processing-based model would be a reasonable approach for estimating the damages in silicon wafers during wire sawing. • A model is developed to determine surface roughness and subsurface damage. • A digital image processing method is proposed to extract fracture parameters. • Distribution characteristics of surface roughness and subsurface damage are studied. [ABSTRACT FROM AUTHOR]

At present, solar energy is the key development of clean energy. Diamond wire sawing (DWS) is the most used processing method of solar crystalline silicon cell wafer. In recent years, the application of crystalline silicon cutting that can be applied by single wire has gradually turned to that of EDWS. However, the research on the equipment and process requirements of endless diamond wire is limited, and the mastery of the equipment factors affecting the performance of EDWS is not perfect. This paper takes the influence of some constituent factors of EDWS equipment on processing performance as the research object; focuses on the analysis of the wire length, wire brand, guide wheel diameter, cutting wheel span, driving wheel position, and wheel number of the EDWS system; and finds out the deep causes and correlation of the influencing factors. It provides a basis for giving full play to the performance of endless wire sawing from the equipment composition. [ABSTRACT FROM AUTHOR]

Monocrystalline silicon wafer is the most important raw material in chip manufacturing; wire sawing is the most common processing method of monocrystalline silicon wafer. The residual stress generated by cutting affects the subsequent polishing costs directly, as well as the fracture strength and mechanical integrity of the monocrystalline silicon wafer, thus affecting the service performance. In this paper, the generation mechanism of residual stress was analyzed based on diamond wire sawing technology. Then, based on Drucker-Prager (D-P) plastic constitutive model, the magnitude and distribution of residual stress of monocrystalline silicon chip under different process parameters were simulated by ABAQUS simulation software. Finally, the experiment of ultrasonic vibration–assisted diamond wire saw cutting monocrystalline silicon was conducted, and the residual stress of monocrystalline silicon chips were detected by blind hole method. During the detection, the strain values before and after drilling in three directions of monocrystalline silicon chips were measured by strain gauge rosette, and then the residual stress values were determined according to the strain values and the residual stress calculation theory. The experimental results showed that residual compressive stress remains on the surface of silicon wafer in both conventional wire sawing and ultrasonic vibration–assisted wire sawing. The residual compressive stress increases with the increase of the axial speed of wire saw, decreases with the increase of the wire saw feed speed, and fluctuates with the increase of the workpiece rotation speed. The residual compressive stress on the surface of the silicon wafer by ultrasonic vibration–assisted wire sawing is larger than that by conventional wire sawing. The simulation and experimental results have the same trend, which verifies the validity of the finite element model in this paper and provides theoretical support for the subsequent processing of single crystal silicon. [ABSTRACT FROM AUTHOR]

Granite, acidic igneous rock, is an ideal choice for architectural decoration. Nevertheless, the severe wear of diamond and the deviation of saw blades restrict the processing of large-size slabs by frame sawing. The slabs need to be polished and then used for building decoration. Therefore, a deep understanding of the effects of machining parameters on the surface morphology and chips features for granitic rocks is significant for solving these issues. In this study, single grain scratch tests were conducted on Brazilian golden granite and Tan brown granite to explore the effect of the machining parameters on the surface morphology and chips features. The experimental tests were performed on a CNC machine, and results were characterized by a laser scanning confocal microscope (LSCM). The materials' surface morphology and chips features were discussed based on crack initiation and propagation, dislocation, plastic deform, and strain rate. Further, the size of detritus was analyzed quantitatively based on strain rate. The experimental results show that machining parameters have a stronger impact on workpiece surface quality, cracks formation, and size of detritus. High strain rates (> 5 × 104 S−1) produce better surface quality and smaller debris. Hence, the strain rate is inferred as the main factor that affects the granite removal mechanism. The findings from this investigation are helpful to understand the processing mechanism of rock materials in the field of stone. [ABSTRACT FROM AUTHOR]

This study presents an opportunity to utilize peeler cores derived from poplar wood for the production of hollow beams. In this way, final products to meet the needs of consumers can be obtained. The proposed novel methods for sawing and gluing the produced materials allow rational application of the waste raw material in the plywood manufacturing. Another advantage in this case is that products with a square cross-section with dimensions close to or corresponding to the standard ones are obtained from small-diameter round wood. The raw material used to receive the proposed hollow beams is up to 33% less than a conventional beam with the same dimensions. The manufactured products are lighter and with a significantly stable cross-sectional shape, compared to natural wood beams with the same dimensions. Sawing the peeler cores and obtaining materials with a triangular and trapezoidal cross-section helps to achieve volume yields from 60.6% to 71.1% of the raw material initial volume. [ABSTRACT FROM AUTHOR]

An embedded load cell sensor is proposed for the tool life prognosis and thrust force control of a band saw machine. The sensor enables the tool life and surface quality of the machined workpiece to be effectively improved through the use of a single sensing device strategically located in the cutting machine. The feasibility of the proposed sensor is demonstrated experimentally using a double-column horizontal sawing machine with medium carbon steel bars as the workpiece material. An investigation is performed into the effects of the cutting force, feed rate, and machining time on the machined workpiece's tool wear and surface roughness. It is shown that the machined workpiece's thrust force, tool wear, and surface roughness are strongly correlated and increase over time. Based on the experimental results, a feedback control system is proposed for maintaining a constant thrust force on the band saw during cutting under even the most challenging conditions. Overall, the results confirm that a single embedded load cell sensor located in a key position can provide effective force monitoring. Such force monitoring enables a control methodology to maintain the optimal cutting conditions in the sawing of medium carbon steel and improve the tool life and machined part quality. [ABSTRACT FROM AUTHOR]

To better understand the rock breakage mechanism and optimize tool performance during rock machining by multidiameter combination saw, the rock processing experiment using a multidiameter combination saw was carried out on the bridge saw to investigate the variation of load with diameter in the combination saw. Furthermore, in this study, the sawing forces, tools wear, and rock breakage in the processing rock were qualitatively analyzed and compared. The experimental investigations demonstrated that the maximum undeformed chip thickness, the load per diamond, and the load in the sawing arc zone all decrease with increasing diameters of the single saw in the combination saw. The sum of the vertical forces of the single saw is generally less than that of the combination saw under the same parameters because of the existence of the coupling effect between the single saws. Different failure mechanisms of particles in the worn segment of the tool with different diameters also operate in rock processing using a multidiameter combination saw. With increasing diameter of saw blade, the proportion of the whole and blunt diamond particles increases, and that of the macro-fractured and pulled-out crystals decreases. Moreover, the differences in the surface integrity are attributed to the variation in the maximum undeformed chip thickness on the saw blade with different diameters in the combination saw and the gully depth on the surface, and the surface roughness of rock decreases with increasing diameter of the single saw. Highlights: The experiments for rock processing by a multidiameter combination saw are designed to investigate the sawing performance of multidiameter combination circular saw with different diameters. Different failure mechanisms of particles in the worn segment of the tool with different diameters operate in rock processing using a multidiameter combination saw. The differences in the surface integrity are attributed to the variation in the maximum undeformed chip thickness on the saw blade with different diameters in the combination saw. Coupling effect between the single saws affects decomposition and generation of forces in the multidiameter saw. [ABSTRACT FROM AUTHOR]

Aluminum honeycomb core (AHC) is extensively applied in aerospace and transportation industries for its exceptional strength-to-weight ratio. However, the unique structure of AHCs limits their manufacture. In this research, the damage mechanism of AHCs is firstly studied with polycrystalline diamond (PCD) circular saw blades to provide high-quality AHCs for wide-format honeycomb composites. The study meticulously examines the various forms of sawing damage incurred by AHCs at different material removal rates (MRR) and categorizes them accordingly. The results show that burrs of AHCs change from tiny blocks to larger strips with the MRR. At high MRR, the predominant failure modes include collapse, deformation, and hot cracking, while at low MRR, AHCs mainly suffer from cracking, micro-collapse, and oxidation by SEM and EDS analysis. A dynamic analytical model of the sawing angle is proposed based on the sawing trajectory to elucidate vibration scratching and burr formation. The effect of the sawing angle is quantified by the deformation displacement and damage area by the optical measurement. The microscopic reciprocating vibration scratching of AHCs is interpreted by the blade's vibration state. The causes of sawing damage at different MRRs are investigated, indicating that at high MRR, the increased impact of the sawtooth leads to severe vibration scratches, collapses, and strip burrs, whereas, at low MRR, the high-frequency scratching of the sawtooth tends to result in tearing and micro-collapses. A comprehensive description of burr formation is presented by a 3D finite element model. Additionally, the cutting heat is the main cause of the oxidation of sawing surfaces by EDS. This systematic investigation analyzes and explores the sawing damage mechanisms of AHCs, offering in-depth insights for optimizing the sawing process to eliminate surface quality problems and improve the sawing efficiency and accuracy of wide-format AHCs. [Display omitted] • Aluminum honeycomb materials can be manufactured by high-speed sawing for obtaining wide-format honeycomb cores. • The damage mechanisms of aluminum honeycomb cores under different material removal rates were finely analyzed and classified. • A dynamic analytical model of sawing angle based on sawing trajectory is proposed. • The sawing burr formation was fully described by 3D finite element modeling. [ABSTRACT FROM AUTHOR]

[Display omitted] • A model to predict sawing vibration scratches was developed. • A dynamic sawing force model was constructed. • A dynamic undeformed chip thickness is proposed based on sawtooth element movement. Carbide circular saw blades are indispensable tools extensively utilized in aerospace and transportation industries. However, modeling of sawing force and dynamic behavior of circular saw blades with large diameter-thickness ratio has rarely been reported. Hence, the aim of this study is to predict the scratches caused by saw tooth vibration on the sawing surface by proposing an axial vibration model for circular saw blades based on the dynamic sawing force. First, the dynamic undeformed chip thickness is established based on the sawtooth element movement method, which presents the circular saw blade geometry, sawing parameters, and so on. A novel dynamic sawing force model is built using this undeformed chip thickness. Then, the axial dynamic response is solved by the additional axial force introduced by the dynamic sawing force. Finally, sawing experiments were carried out, and the results confirmed the feasibility of the model. [ABSTRACT FROM AUTHOR]

The rapacious demand for energy in semiconductor wafer manufacturing industries has significant implications for global warming and wafer manufacturing costs. Assessing sustainability in the multi-diamond wire sawing (MDWS) process is crucial for reducing costs and mitigating environmental impacts. However, sustainable assessment integrated with machinable performance metrics in this process has not been investigated. This novel study extensively analyzes sustainability metrics such as processing time, energy consumption, carbon dioxide emissions, machining cost, and machinability characteristics, including surface roughness, diamond wear rate, and sawing temperature in monocrystalline silicon carbide (mono-SiC) sawing process. Experiments were conducted using traditional MDWS (T-MDWS), reactive MDWS (R-MDWS), and electrophoretic-assisted reactive MDWS (ER-MDWS) coolants. An autoregressive integrated moving average (ARIMA) model was used to predict the overall energy consumption of the MDWS machine. Results showed significant improvements across various responses such as processing time, energy consumption, carbon dioxide emissions, machining cost, surface roughness, diamond wear rate, and sawing temperature, with reductions of 2.95%, 3.87%, 6.80%, 12.82%, 4.68%, 16.32%, and 4.39%, respectively. Furthermore, the ARIMA model results indicate that the total energy consumption prediction accuracy reaches 98.813%. The findings demonstrated that the ER-MDWS cooling strategy is well-suited for large-scale wafer production without compromising surface quality while minimizing environmental impact.Graphical abstract: The rapacious demand for energy in semiconductor wafer manufacturing industries has significant implications for global warming and wafer manufacturing costs. Assessing sustainability in the multi-diamond wire sawing (MDWS) process is crucial for reducing costs and mitigating environmental impacts. However, sustainable assessment integrated with machinable performance metrics in this process has not been investigated. This novel study extensively analyzes sustainability metrics such as processing time, energy consumption, carbon dioxide emissions, machining cost, and machinability characteristics, including surface roughness, diamond wear rate, and sawing temperature in monocrystalline silicon carbide (mono-SiC) sawing process. Experiments were conducted using traditional MDWS (T-MDWS), reactive MDWS (R-MDWS), and electrophoretic-assisted reactive MDWS (ER-MDWS) coolants. An autoregressive integrated moving average (ARIMA) model was used to predict the overall energy consumption of the MDWS machine. Results showed significant improvements across various responses such as processing time, energy consumption, carbon dioxide emissions, machining cost, surface roughness, diamond wear rate, and sawing temperature, with reductions of 2.95%, 3.87%, 6.80%, 12.82%, 4.68%, 16.32%, and 4.39%, respectively. Furthermore, the ARIMA model results indicate that the total energy consumption prediction accuracy reaches 98.813%. The findings demonstrated that the ER-MDWS cooling strategy is well-suited for large-scale wafer production without compromising surface quality while minimizing environmental impact. [ABSTRACT FROM AUTHOR]

When diamond wire saw is used in machining silicon nitride ceramics (Si 3 N 4 ceramics), the ultra-hardness of Si 3 N 4 causes the saw wire to wear out, which leads to the saw wire cutting performance constantly changing during its life cycle, and thus the machined quality of Si 3 N 4 ceramics is affected. Surface roughness and topography are important indicators of the quality of the machined surface. In this paper, the diamond wire saw cutting experiment of Si 3 N 4 ceramics was carried out, the effect of the evolution of saw wire cutting performance on the surface roughness and topography of Si 3 N 4 ceramics as-sawn slices was investigated based on the analysis of the changes of saw wire wear topography, breaking force, bow angle and kerf loss during the sawing process. The results show that the surface roughness along the saw wire motion direction and the workpiece feed direction tends to decrease and then increase with the evolution of the cutting performance of the saw wire, which accords well with the trend of the as-sawn slices surface morphology. The results of the study can provide experimental reference for the development of high precision diamond wire saw cutting technology for Si 3 N 4 ceramics. [ABSTRACT FROM AUTHOR]

The cooling method of silicon material sawing in solar energy industry is jet cooling and flood cooling. In this paper, a machining method of diamond wire electrical discharge sawing (DWEDS) under environmentally improved bath cooling was proposed. Its advantages were compared to jet cooling by carrying a series of sawing tests. It was found that DWEDS under bath cooling obtained better machining accuracy and better surface quality than that under jet cooling. Also, the machining accuracy and cutting efficiency in DWEDS were better than those in diamond wire sawing (DWS). The same conclusions were proved by scanning electron microscope observation of the wafer surface. In addition, the wire tension in DWEDS sawing was found more stable than that in DWS. Finally, the wire wear was as another indicator to evaluate the cooling effect. No significant difference in wire wear between bath cooling and jet cooling was found. However, the wire wear of DWEDS under the same cooling method is higher than that of DWS, which means the discharge effect is helpful to the wire self-sharpening from another point of view. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hierarchical capillary adhesion model of wafers during diamond wire slicing is presented. • Capillary adhesion has a greater effect on the large and thin wafers slicing with a fine wire. • Capillary adhesion significantly increases the risk of wafer fracture for thickness below 100 μm. • As wafer thickness decreases to 50 μm, the 210 × 210 mm2 mono-Si wafer fracture probability caused by capillary adhesion increases to more than 6%. As the photovoltaic industry needs to reduce manufacturing costs, the kerf loss and the wafer thickness of diamond wire slicing will be further reduced in the future, which will make the spacing and bending rigidity of the wafers decrease to the extent that the effect of capillary adhesion of wafers is more significant during slicing, thus increasing the risk of silicon wafer fracture. Therefore, a hierarchical capillary adhesion model of wafers during the diamond wire slicing based on the principle of minimum potential energy is established in this paper. The variation of the maximum bending stress and the number of adhered wafers with sawing depth, kerf width, and wafer thickness and the effect of capillary adhesion on the silicon wafer fracture are studied. The results show that the maximum bending stress and the number of adhered wafers increased with the increase of the sawing depth, which meant that the risk of wafer fracture was greater for sawing large-sized wafers. And they also tended to increase as the kerf width and the wafer thickness decreased, that was, the effect of capillary adhesion on the thin wafer sawn with a fine diamond wire was more significant. In addition, the probability of the mono-Si wafers fracture caused by capillary adhesion increased significantly when the wafer thickness was less than 100 μm. The research work is of great significance for further research on the thin wafers slicing technology with the fine diamond wire to reduce the manufacturing costs of silicon wafers in the photovoltaic industry. [ABSTRACT FROM AUTHOR]

Nowadays, the efficiency improvement of diamond wire sawing (DWS) of photovoltaic silicon through fine wire and high-speed sawing has met the development bottleneck. This paper is a change of thinking to provide a diamond wire electrical discharge sawing (DWEDS) method to integrate the machining efficiency of DWS and electrical discharge machining (EDM), which has more advantages than the current DWS method in sawing efficiency, kerf loss, wire mark, and surface uniformity. In order to evaluate the wire sawing efficiency considering the influence of wire bow and kerf width, a new method was proposed more suitable for the efficiency evaluation of DWEDS and DWS. The efficiency of DWEDS was proved better compared with EDM and DWS. The performance of DWEDS in the aspect of silicon loss is better than that of EDM and DWS as its kerf width is smaller. The discharge effect is used to reduce the wire marks caused by the physical cutting effect of DWS. The grain sawing is better for surface roughness compared with EDM. Also, it is found that the thickness of damaged layer produced by DWEDS is related to the contribution of physical cutting and discharge effect, which is significantly lower than that of EDM. Besides, the wire consumption of DWEDS is higher than that of DWS, but the reconsolidation of the diamond wire after discharged melting will expose more grains to ensure the wire cutting capability. [ABSTRACT FROM AUTHOR]

Although distributed fiber sensing techniques have been widely used in structural health monitoring, the measurement results of bridge monitoring, particularly under destructive testing, have rarely been reported. To the best of our knowledge, this paper is the first report of distributed vibration measurement results, which we obtained during a three-day destructive test on an abolished bridge. A coherent optical time domain reflectometry (COTDR) was used to acquire the vibration information while the bridge was being sawed. The obtained signal was analyzed in time and frequency domain. Some characteristics of the sawing-induced vibration were retrieved by the short-time Fourier transform; the vibration exhibited several high frequency components within the measured range up to 20 kHz and all the components appeared in the same time slot. Some unexpected signals were also detected. Thorough analysis showed that they are quite different from the sawing-induced vibration and are believed to originate from internal damage to the bridge (probably the occurrence of cracks). [ABSTRACT FROM AUTHOR]

High-speed wood sawing results in an uneven surface were evaluated. Machine structure was redesigned to reduce noise and unevenness of such sawing. A crawler track is driven by an auxiliary wheel. The roller seat on top of the board saw stabilises chain pieces. Investigations revealed some influencing mechanical factors, including static deformation, resonance excitation, and rigid body collision. A complete chain feed model was constructed to analyse related acoustic noise. Quantitative analysis enabled a successful redesign of chain feed elements. Chain feed simulation enabled the reduction of conflicting factors and revealed the optimal shape for chain links. The structural deformation of die casting indicated the possibility of variation in the chain shape. The flatness of the chain surface was reduced, and noise generated during the collision of links was minimised. Simplified modelling enabled identification of problems in the multi-blade system. [ABSTRACT FROM AUTHOR]

The normal processing of sintered NdFeB magnets, used in many applied fields, involves diamond wire sawing. Due to the fact of its relatively lower hardness and high brittleness, the surface roughness and periodic waviness of the sawed surface have become a serious problem, but the surface formation mechanism is still unknown. In this work, a diamond wire sawing experiment with a NdFeB magnet was conducted while both the cutting force and the diamond wire lateral displacement were monitored. The vibration, the lateral swing of the wire and the cutting force were thoroughly analyzed. After the experiment, the surface morphology was carefully inspected under both a white light interferometer and SEM. It was discovered that the lateral swing of the diamond wire was the main cause of the periodic waviness on the surface, the PV of which was positively proportional to the normal cutting force. The surface morphology and surface roughness along the saw mark revealed that the vibration impact of ploughing/rubbing grits can induce the NdFeB grain to loosen off and cause more brittle fractures when the feed rate was 0.05 mm/min under wet cutting. [ABSTRACT FROM AUTHOR]

Square wire sawing (squaring) is the preceding process of silicon ingot grinding and slicing for solar wafer manufacturing. The machining accuracy will affect the machining efficiency of the grinding process, and affect the quality of slicing. At present, extreme difference (ED) method is used for the evaluation of squaring accuracy, which cannot fully reflect the squaring accuracy. Novel evaluation method of straightness difference (SD) and flatness difference (FD) of squaring were proposed. The evaluation process was compared with ED method. The results show that the novel method can solve the defects that cannot be sufficiently evaluated by ED method. In addition, the profile errors of the cross sections along and perpendicular to longitudinal direction and the surface contour errors on the symmetric surface were evaluated. The relationship between the error distributions along the longitudinal direction and the processing parameters was also found, which provides help for optimizing the process. [ABSTRACT FROM AUTHOR]