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Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The transverse leakage of leaky surface acoustic waves (LSAWs) occurs on 42°YX-lithium tantalate substrates (42LT), which increases the insertion loss, narrows the bandwidth and flattens the roll-off of band 40/41 SAW filters and duplexers. In this work, LSAW characteristics with different metal materials and thicknesses are calculated by the finite element method (FEM), which determines the IDT material and thickness used for band 40/41 SAW filter design. To deeply understand transverse leakage and suppress it, the effects of different gap and dummy lengths on transverse leakage are simulated and discussed. Then, a new technique of using a wider dummy without any additional lithographic or depositing processes is proposed to suppress the leakage. Its effectiveness is validated by both simulations and experiments. Then, the technique is extended to applications of band 40 and 41 SAW filters. The experimental results show that with the wider dummy structure, the band 40 and 41 SAW filters achieve a more than 0.2 dB improvement in the insertion loss, a wider bandwidth and a steeper roll-off characteristic. This technique may also be extended to the other band SAW filter applications. [ABSTRACT FROM AUTHOR]

One of the major disadvantages of band saws is their low durability. Breakages during the operation are mostly caused by fractures in notches between the blades of the band as a result of the fatigue phenomenon. The strength of the band saw blades is ensured if the assurance coefficient value is greater than the theoretically determined one. The value of the assurance coefficient of 2 is recommended. A schematic limit-amplitude diagram was used to calculate the durability of band saws. A formula for the estimation of the assurance coefficient was derived. It was used for the calculation of the assurance coefficients of the band saw blades manufactured in accordance with GOST 6532–77, which are applicable in dividing band saw machines. The resulting value of the assurance coefficient was 1.44. The value is extremely low for the band saws because it is much lower than required. Band saw blades should be sharpened regularly to ensure a long and reliable service life. It should be made not only to ensure the required sharpness of the blades but also to remove the defective layers in notches caused by fatigue phenomena. In the article, there are more recommendations for improving the durability of the blades of the band saws. The durability of a new type of band saw with curved aerostatic guides and hard alloy blades was evaluated. Its assurance coefficient was 2.4. Therefore, the machine can be operated reliably for a long time without regular treatment of the notches. Consequently, band saws have low durability due to their increased breakdown rate and low wear resistance. Hence, the costs of their purchase and treatment rise. Therefore, the results presented in the article are practically applicable. For citation: Prokofiev G.F., Kovalenko O.L. Fatigue Strength of Band Saws. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. 136–145. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-136-145

Sawing is a commonly utilized undercutting process for machining in the steel and forging industries. With the continuous improvement of modern processing requirements and increasing demands for higher sawing efficiency, accuracy, and surface quality of workpieces, bi-metal band saw blades are facing greater challenges. In addition, the development of new and difficult-to-cut materials such as nickel-based alloys, titanium alloys, and other heterogeneous alloys has presented novel challenges to band sawing technology. However, the wear of the band saw blade has become a major hindrance to the application and development of sawing processing technology for new materials, high efficiency, high precision, etc. Based on the principle of metal cutting using a band saw blade and considering the wear process of teeth, this paper provides a comprehensive analysis of the impact of cutting parameters, cutting fluid, heat treatment, and surface treatment technology on tooth wear. Additionally, measures to enhance wear resistance are summarized. Furthermore, an overview is presented regarding the latest advancements in monitoring wear for bi-metal band saw blades. Finally, the future direction of research on wear in bi-metal band saw blades is anticipated. [ABSTRACT FROM AUTHOR]

Machine tools are required to be able to produce workpieces according to the desired technical requirements. The goal of machining is to achieve a high production volume of good quality with maximum tool life, short production time, and low cost. The surface properties obtained as a result of the changing and developing technology in cutting processes, the introduction to manufacturing, and especially the post-processing processes are of great importance. While the time obtained as a result of fast cuts has economic value, high-quality surface obtaining provides cost savings by minimizing the subsequent machining operations. Within the scope of the study, Ø120 mm ST-52 and Ø120 mm AISI 4140 materials have been cut with smart and automatic cutting modes by our domestic band saw machine. As a result of the cuts, the roughness values and curvatures of the samples have been checked with the surface roughness device and surface gauge. While the surface roughness after cutting was 4.45 µm with the automatic cutting mode, this value decreased by 16% to 3.71 µm with the smart cutting mode. [ABSTRACT FROM AUTHOR]

Copyright of Revista Chapingo Serie Ciencias Forestales is the property of Universidad Autonoma Chapingo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the goal of finding out how much design-led innovation can offer to a B2B-oriented family-run company, this work presents a case study within an industry notorious for its reluctance to invest in design. We examine a company that manufactures horizontal and vertical log band saws, which began employing the services of a design studio only in 2014. In addition to quantifying the tangible, measurable effect that the design studio has had on the company's ecosystem, the article also helps to broaden our understanding of the importance of innovation in the context of a family-run company's coevolution. [ABSTRACT FROM AUTHOR]

In rural, isolated areas, sawmills are often equipped with one or more small-capacity hand-fed band saws. Even in this situation, the productivity of the band saw must be viewed through the factors that influence it, namely the characteristics of logs and the optimization of the stages and activities carried out. Therefore, time consumption, the structure of working time and the recovery rate in sawing logs into lumber provide important information for users. The structure of the sawing operation for a work team made up of an operator and an assistant was divided into six work stages. The sawing pattern used involves sawing the log up to approximately half of the diameter, then rolling the log with 180° and continuing the sawing, aiming to obtain lumber with a thickness of 40 and 50 mm from the central part of the log. The productivity was 2.45 m3·h−1, the recovery rate was 70.84% and the working time real-use coefficient was 0.37. Research has highlighted the positive correlation between working time and the middle diameter of the logs (R2 = 0.84). The feeding speed was also determined along with the quality of cuts, which was expressed by the thickness uniformity of the lumber and the presence of cutting teeth traces on the newly created surfaces. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate energy harvesting of surface acoustic waves (SAWs) via topological interface states in a two-dimensional phononic crystal (PC) with the periodic arrangement of bar-like locally resonant units on its surface. The system can produce pure SAW bands in the subwavelength realm due to bar oscillation. Both transverse and longitudinal vibrations of the stubbed bar can selectively couple to the intrinsic SAWs in the PC slab. Subsequently, through constructing the typical Su–Schrieffer–Heeger model, we analyze the topological properties of zone-folding-induced SAW bands with transverse and longitudinal vibration characteristics, respectively. When two arrays with distinct topological bandgaps are spliced together, topological interface states will appear. Topological energy harvesting of SAWs with two different vibration characteristics is finally achieved in one structure. Our study expands the applicability of topological interface states for SAW in a compacted platform, such as polarization selection or sensing. [ABSTRACT FROM AUTHOR]

Sawing is often the first work step in the metal cutting production chain. Especially for larger workpieces, bandsawing is used for this purpose. Nevertheless, studies on sawing have led a niche existence in the research landscape for a long time. However, as a result of the optimization of manufacturing processes in terms of economic efficiency, bandsawing is increasingly becoming the focus of research, since there are still saving potentials here. The aim of this paper is to investigate the extent to which the bandsawing process can be influenced by active, low-frequency vibration superimposition in the feed direction. First, analogue tests were carried out and parameter combinations were determined which have a positive influence on the process. Subsequently, these parameter combinations were investigated on a real sawing machine with an excitation unit, analysing the extent to which the results from the analogue tests could be transferred to the real process. [ABSTRACT FROM AUTHOR]

Due to the advances in surface treatments, it is possible to obtain excellent cutting tools. However, the field for wood cutting tools still needs to be further investigated. In this work, titanium nitride was deposited on bandsaw blades by the cold plasma technique to increase the lifespan of the wood cutting tool, improving the coated surface. Tests were performed by varying the conditions in the amount of nitrogen and time. In addition, the industrial physical vapor deposition technique was also performed as a comparison. The morphology, structural changes and chemical mapping of the coated samples were investigated with a focus on their mechanical properties by nanoindentation and tribology tests. The surfaces were coated uniformly, with a well-adhered TiNx layer identified by X-ray diffraction and Raman spectroscopy and the electron-dispersive X-ray spectroscopy technique, it was possible to identify the presence of nitrogen in all deposited films. Although no significant differences were observed in hardness values for cold-plasma treated surfaces compared to the uncoated, their friction coefficients and wear values were lower. Physical vapor deposition coated samples had the lowest friction coefficient and wear values. In field trials, the coated cold plasma bandsaw blades had the lowest deviation when cutting the wood and show that this technique can be used for this purpose. [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]

In this paper, we present novel finite two-term cosine time functions, whose frequency responses exhibit triple pass bands, and these bands have the narrowest possible null-to-null lobe width ( ± 1 / T , where T is the duration of the time function), equal to that of a rectangular window. More importantly, these functions provide much higher decay of sidelobes (18 dB/octave) than that is obtainable (6 dB/octave) from the rectangular window. Therefore these functions can be used for designing triple band surface-acoustic-wave (SAW) filters, or for synthesizing the finite-impulse-response filters requiring triple bands. As an example, a triple band SAW filter centered at 25 MHz is designed employing two interdigital transducer structures. The modeling of the electrode-overlap pattern as a sampled data structure is explained, and the simulated frequency plot of the triple band SAW filter is shown. [ABSTRACT FROM AUTHOR]