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The purpose of this paper is to study the influence of the processing parameters of diamond wire sawing on surface morphology and roughness.

First, a wire saw cutting model is established to determine the positional relationship between a wire saw and the machined surface of the workpiece, and the abrasive grain cutting trajectory is generated. Through the data processing of the cutting trajectory, the simulation of the three-dimensional surface topography of the slice and the calculation of the surface roughness are realized by using the GUI programming of MATLAB. Finally, different surface roughness values are obtained by changing the machining parameters (saw wire speed and workpiece feed speed).

The conclusion is that the surface roughness of the slice is larger when the feed speed is higher and smaller when the linear speed is higher.

Diamond wire saw cutting is the first process of chip processing, and its efficiency and quality have an important impact on subsequent processing. This paper will focus on the influence of the sawing wire cutting processing parameters (sawing wire speed and workpiece feed speed) on the surface roughness to optimize the processing parameters and obtain smaller surface roughness values. Through MATLAB three-dimensional simulation, the surface morphology can be observed more intuitively, which provides a theoretical basis for improving the processing quality.

The purpose of this study is to address the issue of technology equipment formerly dedicated to the process of 4- and even 5-inch photovoltaic cells and whose use has become critical with the evolution of silicon wafer size standards (M2–M10). Fortunately, the recent concept of 6'' half-cut cell with its many advantages appears promising insofar as it offers the possibility of further extend the use of costly, still operational process equipment, but doomed to obsolescence.

In the background of a detailed Al-BSF process, the authors show how to experimentally adapt specific accessories and arrange 6” half-wafers to enable the upgrade of a complete industrial process of silicon solar cells at a lower cost. Step by step, the implementation of the processes for the two wafer sizes (4” wafers and 6” half wafers) is compared and analyzed in terms of performance and throughput.

Globally, the same process effectiveness is observed for both types of wafers with slightly better sheet resistance uniformity for the thermal diffusion carried out on the half wafers; however, the horizontal arrangement of the wafer carriers in the diffusion and the plasma-enhanced chemical vapor deposition tubes limits the thermal balance regarding the total number of cells processed per batch.

In terms of the development of prototypes on a preindustrial scale, this paves the way to further continue operating outdated equipment for high-performance processes (passivated emitter and rear contact, Tunnel oxide passivated contact (TOPCon)), while complying with current standards for silicon wafers up to M10 format.

Lapping is a vital flattening process to improve the quality of processed semiconductor wafers such as single-crystal sapphire wafers. This study aims to optimise the lapping process of the fixed-abrasive lapping plate of sapphire wafers with good overall performance [i.e. high material removal rate (MRR), small surface roughness (Ra) of the wafers after lapping and small lapping plate wear ratio (η)].

The influence of process parameters such as lapping time, abrasive size, abrasive concentration, lapping pressure and lapping speed on MRR, Ra and η of lapping-processed sapphire wafers was studied, and the results were combined with experimental data to establish a regression model. The multi-evaluation index optimisation problem was transformed into a single-index optimisation problem via an entropy method and the grey relational analysis (GRA) to comprehensively evaluate the performance of each parameter.

The results revealed that lapping time, abrasive size, abrasive concentration, lapping pressure and lapping speed had different influence degrees on MRR, Ra and η. Among these parameters, lapping time, lapping speed and abrasive size had the most significant effects on MRR, Ra and η, and the established regression equations predicted the response values of MRR, Ra and η to be 99.56%, 99.51% and 93.88% and the relative errors between the predicted and actual measured values were <12%, respectively. With increased lapping time, MRR, Ra and η gradually decreased. With increased abrasive size, MRR increased nearly linearly, whereas Ra and η initially decreased but subsequently increased. With an increase in abrasive concentration, MRR, Ra and η initially increased but subsequently decreased. With increased lapping pressure, MRR and η increased nearly linearly and continuously, whereas Ra decreased nearly linearly and continuously. With increased lapping speed, Ra initially decreased sharply but subsequently increased gradually, whereas η initially increased sharply but subsequently decreased gradually; however, the change in MRR was not significant. Comparing the optimised results obtained via the analysis of influence law, the parameters optimised via the entropy method and GRA were used to obtain sapphire wafers lapping with an MRR of 4.26 µm/min, Ra of 0.141 µm and η of 25.08, and the lapping effect was significantly improved.

Therefore, GRA can provide new ideas for ultra-precision processing and process optimisation of semiconductor materials such as sapphire wafers.

The purpose this paper is to develop an additive manufacturing (AM) technique for high‐strength oxide ceramics. The process development aims at directly manufacturing fully dense ceramic freeform‐components with good mechanical properties.

The selective laser melting of the ceramic materials zirconia and alumina has been investigated experimentally. The approach followed up is to completely melt ZrO₂/Al₂O₃ powder mixtures by a focused laser beam. In order to reduce thermally induced stresses, the ceramic is preheated to a temperature of at least 1,600°C during the build up process.

It is possible to manufacture ceramic objects with almost 100 percent density, without any sintering processes or any post‐processing. Crack‐free specimens have been manufactured that have a flexural strength of more than 500 MPa. Manufactured objects have a fine‐grained two‐phase microstructure consisting of tetragonal zirconia and alpha‐alumina.

Future research may focus on improving the surface quality of manufactured components, solving issues related to the cold powder deposition on the preheated ceramic, further increasing the mechanical strength and transferring the technology from laboratory scale to industrial application.

Potential applications of this technique include manufacturing individual all‐ceramic dental restorations, ceramic prototypes and complex‐shaped ceramic components that cannot be made by any other manufacturing technique.

This new manufacturing technique based on melting and solidification of high‐performance ceramic material has some significant advantages compared to laser sintering techniques or other manufacturing techniques relying on solid‐state sintering processes.

The purpose of this study is the evaluation of the cost and benefits of earthquake protection of buildings to verify whether the legislative push, through tax incentives, will produce results and lead to a redevelopment of private real estate assets.

Through contingent valuation, this research aims to measure the propensity of homeowners to invest in the seismic security of their properties. The sample of homeowners was selected in a southern Italy city, which was characterized by a medium-high seismic hazard. The willingness to pay, once made independent from the family income, was compared with the actual cost of a seismic retrofitting technique to assess its cost-effectiveness.

The analysis developed on an example case shows that the economic sustainability of the intervention is only verified when considering the current tax incentives for this type of intervention.

Choosing to introduce a system to compulsory insurance against seismic risk could certainly be a strong incentive for the implementation of retrofitting interventions on private real estate assets. In this direction, investigations like this can be fundamental to establish the fair risk premium.

The need for effective seismic risk mitigation policies is also based on the growing awareness of the, often fatal, effects of seismic events, emphasized by the recent medium and high intensity events that hit Italy. The issue of the security of residential buildings is therefore a very topical issue in view of their high seismic vulnerability and the vast number of buildings requiring major seismic retrofitting. Therefore, the propensity of owners to intervene in improving the seismic performance of their properties can be crucial in seismic risk mitigation.

Epoxy resins are widely used in a variety of engineering applications, including composite wind turbine blades used in the renewable energy industry, highly complex structural components for aircraft, paints, coatings, industrial tooling, biomedical systems, adhesives, electronics and automotive. Epoxies' low fracture toughness is one of the key obstacles preventing its adoption in a wider range of applications. To address epoxy's low fracture toughness, this paper aims to examine the roles of intra-ply hybridization and nano reinforcing.

This paper investigates the role of intra-ply hybridization of glass-carbon woven fibers and adding 0.8 wt.% of multiwall carbon nanotube (MWCNT) nano reinforcement to overcome the low fracture toughness of epoxy. A bending test is used to calculate the composites elastic parameters, and a notched sample three-point bending test is used to show crack behavior in addition to using materials characterization methods to reveal the effect of the MWCNT on structure, bonding, glass transition temperature (Tg) and dispersion of MWCNT in the matrix. Furthermore, this paper suggests using the finite element method to overcome the difficulty in calculating the crack extension.

Intra-ply hybridization and MWCNT reinforcement decrease the crack extension of epoxy with time. The inclusion of high-strength carbon fiber increased the fracture toughness of glass composite. Furthermore, the existence of MWCNT in the surrounding area of the notch in epoxy composites hinders crack propagation and provides stiffness at the interface by bridging the crack and eventually enhancing its fracture toughness.

Studying the role of intra-ply hybridization of glass-carbon woven fibers and adding 0.8 wt.% of MWCNT nano reinforcement to overcome the low fracture toughness of epoxy. Additionally, this research recommends using the finite element method to overcome the challenge of computing the crack extension.

This study aims to investigate the correlation between build orientation characteristics, part porosity and mechanical properties of the fused filament fabrication (FFF) process to provide insight into pore formation mechanisms and to establish guidelines for optimal process configurations.

Micro computed tomography and metallographic sections provide the basis for a correlation between porosity and extrusion path. Using the correlations found in this study, the way to improve printing strategies and filament properties can be deduced directly from an analysis of the print path and the final influence on mechanical performance.

With metal-FFF 3D printing technology, near-dense parts (0.5 Vol.%) can be fabricated. The pore architecture is strongly connected to the build direction and print strategy with parallel, elongated pore channels. Mechanical values of FFF samples are similar to metal injection-molded (MIM) parts, except the elongation to fracture. The high difference of yield strength of sintered samples compared to laser powder bed fusion (LPBF) samples can be attributed to the finer grains and a Hall–Petch hardening effect. The conclusions derived from this study are that the presented process is capable of producing comparable part qualities compared to MIM samples, with higher build rates in comparison to LPBF processes.

316L stainless steel was successfully manufactured via FFF. This paper also addresses the effects of scanning strategies on the resulting porosity and proposes improvements to reduce residual porosity, thus increasing the mechanical performance in the future.

The PROCESS OF MAKING WIRE by drawing operations through dies, as distinct from hammering, though believed to be several thousand years old, until the last century was performed only by man‐, horse‐ or water‐power, so that production was slow and small. These old methods could not meet the greatly increased demand that then arose for wire of all kinds, such as copper wire for electrical purposes, and consequently power‐driven multi‐die benches were developed. Drawing speeds were still limited to several hundreds of feet per minute because of the rapid wear of the chilled iron and steel dies then used; but with the introduction of tungsten carbide dies and diamond dies, speeds were again increased, and now figures of 2,000 ft. per minute for steel wire, and 5,000 ft. per minute or more for copper and aluminium, are commonplace. These advances have required improved drawing lubricants, and future increases in drawing speeds likewise largely depend on improving lubricants still further. The general problem is to provide adequate lubrication for long die life, coupled with the intensive cooling that higher drawing speeds compel.

INCREASING demand for stone products has led to numerous new quarries being opened up and worked all over the world. As a result of this expansion, the variety of stone types available has increased. This can present initial problems when determining the correct diamond and bond specifications for the diamond tools used to cut and drill these materials. It is difficult to make precise judgements without carrying out extensive machining trials to establish the sawability of a given stone type.