Sawing System Research Articles

Development of a novel circular saw blade substrate with high stiffness for mitigating vibration noise and improving sawing performance

The circular saw blade substrates featuring a large diameter-thickness ratio and multiple saw teeth are increasingly required to accomplish the first or second machining tasks with high efficiency in sawing operations. However, the weak bending stiffness of this substrate can easily cause intense vibrations and harsh noises, while its special structure characteristics pose further challenges to vibration mitigation. This research develops a novel circular saw blade substrate with high bending stiffness to improve dynamic stability. Taking the geometric features and boundary conditions of the substrate into account, a transverse vibration differential equation for high-speed sawing operation is established to investigate the relationship between the mode shapes of the substrate and the stability performance of the sawing system. Theoretical analysis shows that the laminated structure can enhance the bending stiffness. Using this finding, the novel substrate is designed equipped with an m-shaped damping cavity and a laminated core structure, and its dynamic performance is quantified by the complex modulus law and thin-plate vibration theory. Then, the optimized design of the relevant materials and geometrical dimensions of the novel substrate is executed by the pseudo-density method. Finally, the novel substrate is fabricated and then certified by sawtooth point dynamics tests and sawing experiments. The experimental results show that the sawing quality of the novel substrate is improved by more than 50.2 %, and the sawing vibration and weighted sound pressure level are reduced by about 35 % and 12 dB(A), respectively, compared with the conventional one.

Suppression of electromagnetic crosstalk by differential excitation for SAW generation

Surface acoustic waves (SAWs) hold a vast potential in various fields such as spintronics, quantum acoustics, and electron-quantum optics, but an electromagnetic wave emanating from SAW generation circuits has often been a major hurdle. Here, we investigate a differential excitation method of interdigital transducers to generate SAWs while reducing the electromagnetic wave. The results show that electromagnetic waves are suppressed by more than 90 % in all directions. This suppression overcomes the operating limits and improves the scalability of SAW systems. Our results promise to facilitate the development of SAW-based applications in a wide range of research fields.

Experimental Study on Surface Integrity of Solar Cell Silicon Wafers Sliced by Electrochemical Multi-Wire Saw.

Electrochemical multi-wire sawing (EMWS) is a hybrid machining method based on a traditional multi-wire sawing (MWS) system. In this new method, a silicon ingot is connected to a positive electrode; the slicing wire is connected to a negative electrode. Material is removed by the interaction of mechanical grinding and an electrochemical reaction. In this paper, contrast experiments of EMWS and MWS were conducted based on industrialized equipment to verify the beneficial effects of the hybrid method. The experimental statistical results show that the composite processing method improved the processing qualification rate by 1.28%, and the Bow of silicon wafers was reduced by about 2.74 microns. Further testing on the surface of the silicon wafer after electrochemical action showed that obvious holes were present on the surface, and the surface hardness of the wafer decreased significantly. Therefore, the scratches on the surface of wafer sliced by EMWS were reduced; in addition, the thickness of the surface damage layer was reduced by about 9 microns. After standard texturing, the average reflectivity of the wafers sliced by EMWS was about 2–10% lower than that of the wafers sliced by MWS in the wavelength of 300–1100 nm. In this paper, the voltage parameter of the composite machining is set to 48 V; the amount of electrolyte added in each experiment is 2 L; and a good machining effect is obtained. In the future, the electric parameters and cutting fluid components will be further studied to improve the electrochemical effect.

Assessment of machine learning algorithm-based grading of Populus x euramericana I-214 structural sawn timber

The efficiency of visual grading standards applied to structural timber is often inappropriate, and timber properties are either under or over-graded. Although not included in the current UNE 56544 visual grading standard, machine learning algorithms represent a promising alternative to grade structural timber. The general aim of this research was to compare the performance of machine learning algorithms based on visual defects, non-destructive techniques and sawing systems (“cut type”) with UNE 56544:1997 visual grading in order to predict the qualifying efficiency of Populus x euramericana I-214 structural timber. Visual evaluation, ultrasound and vibrational non-destructive testing, and sawing systems register (radial, tangential and mixed) were applied to characterize 945 beams. In addition, in order to retrieve actual physical-mechanical values, density and static bending destructive testing (EN-408:2011 + A1:2012) was also carried out. Several machine learning algorithms were then used to grade the beams, and their predictive accuracy was compared with that of visual grading. To do so, three scenarios were considered: a first scenario in which only visual variables were used; a second scenario in which “cut type” variables were also included; and a third scenario in which additional non-destructive variables were considered. Results showed a poor level of performance of UNE 56544:1997, with an apparent mismatch between the strength values assigned for each visual grade (established by the EN 338 standard) and the actual values. On the opposite, all algorithms performed better than visual grading and may thus be deemed as promising timber strength grading tools.

Processes and mechanisms of phosphorus mobility among sediment, water, and cyanobacteria under hydrodynamic conditions.

Phosphorus (P) has an important role in eutrophication and it is essential to explore the processes and mechanisms of P mobility in natural waters. In this study, laboratory experiments were conducted to simulate the SW system (sediment and water) and SAW system (sediment, algae, and water) under four hydrodynamic intensity conditions (static control, 50 rpm, 125 rpm, and 200 rpm treatments), to investigate P mobility. Results in SW system showed that sediment was an important source of P for overlying water, and the released total P (TP) increased with stronger hydrodynamic intensity, when P associated with metal pools (redox-sensitive P [BD-P] and meta-oxides bound P [NaOH-P]) were the most unstable and easier to migrate into the overlying water. Stronger hydrodynamic disturbances could enhance the processes including sediment resuspension, dissolution of particles, and release of P, when P mobility had a close relationship with redox conditions near sediment-water interface (SWI). Therefore, the release of TP, BD-P, and NaOH-P from sediment increased and decreased in the control and 50-200 rpm treatments over time. In SAW system, the release of TP significantly increased from sediment comparing to SW system, and the growth of Microcystis aeruginosa could selectively enhance the release of BD-P, NaOH-P, and organic P (OP). Meanwhile, the released P from sediment was quickly accumulated by algal cells. The maximum accumulation ability of P by cells, the highest photosynthetic efficiency, and the best growth of M. aeruginosa were observed in 125 rpm treatment. But with excessively strong hydrodynamic intensity (200 rpm treatment), the accumulation ability of P and alkaline phosphatase activity (APA) of M. aeruginosa was suppressed, which might hinder algal utilization of P and inhibit algal growth. Overall, our findings demonstrated the patterns of P mobility in natural ecosystems and could contribute to the understanding of P cycling.

Automating Steel Storage & Processing

Waser Stahl has upped its competitiveness with the installation of a storage, sawing and robotic handling system by Kasto

Establishing empirical relationship between welding current and weld metal deposition rate for submerged arc welding process

Any increase in the productivity of the SAW process will immensely benefit the welding industry, as this process is widely used. Since the traditional single wire DCEP SAW system is extensively used even today, any enhancement using this system will benefit the industry in a big way, if this traditional SAW system is part of the improvisation process. This paper establishes a relationship between welding current and productivity (deposition rate), for the three common sizes of both solid wires and metal cored tubular wires at different current values over its full range, through bead-on-plate experimentation. At each preset current value, the weld bead was optimized for acceptable visual quality, by adjusting arc travel speed and voltage, then the wire feed rate-making optimized bead was noted. The weld metal deposition rate was calculated for establishing A vs WMDR empirical relationships. From the results, ten progressive strategies have been established which can improve welding productivity from 21 to 211% from baseline. The established relationships, strategies can be effectively used, to estimate/optimize the productivity based on the welding current values, for each wire type and diameter.

Value chain analysis of farm grown Melia volkensii (Gurke) timber in the South Eastern Dry lands of Kenya

This paper analyzes the value chain of Melia volkensii timber grown on farms in the South Eastern dry lands of Kenya. The “filiere” approach was used to analyze the institutional and the economic dimensions of the chain, while technical dimensions were analyzed using on-farm timber sawing systems. Six main actors; tree farmers, timber merchants, sawyers, timber yard operators, furniture makers, and end consumers were mapped. Transporters, though temporary, played intermediary roles of facilitating the linkages. A variety of combinations determined costs and gains along the chain. Some actors circumvented some links to increase revenue. Quality of trees and sawn timber were key determinants of monetary value transacted along the chain. Inadequate farmers’ skills in tree silviculture, valuation and cumbersome procedures in obtaining Government permits were also mentioned as major challenges, while timber sawyers lacked efficient sawing technology, consequently lowering income along the entire value chain. To improve the value chain, there is need to address the identified challenges through enhancing information and technology transfer to the players among other interventions. Key words: Farm grown timber value chains, Melia volkensii, “filiere” approach, chainsaw.

Application of DCT to problem of collision resolution in RFID SAW systems by using correlation method

The article is devoted to SAW RFID systems. A problem of collision resolution by using a correlation method is under consideration. Collision is resolves by means of two correlation features, by the correlation function of the signal and by the correlation function of the DCT from the signal. A program, which is implements such collision resolution algorithm, was written. A collision is creating by using a simulation model of RFID tag. The model can generate a response from tag with «own» or with a random code, or can generate a collision of responses with random codes, which may contain or not contain an «own» code. The results of the algorithm’s operation are presented for the cases of reading from two to ten tags simultaneously. In addition to the main function, the algorithm implements error-correcting coding and decoding functions. It allows eliminating errors in case when there is no collision of tags, but a level of channel noise is high. The error-correcting coding is implemented by Reed-Solomon codes.

A new bone-cutting approach for minimally invasive surgery

AimsResection of bone is performed in over 75% of all orthopaedic procedures and the electrically powered oscillating saw is commonly used to cut bone. Drawbacks are relatively large incisions and tissue damage due to overshooting often occur. Therefore, the goal of this study is to develop an improved bone-cutting system that has minimally invasive characteristics. MethodsA new reusable sawing system was designed that can be used in Minimally Invasive Surgery (MIS) consisting of a steerable wire passer and a tissue saving wire saw guide. The system was tested during surgery on a human cadaveric tibia and calcaneus. ResultsA MIS steerable compliant Nitinol needle was built and successfully used in a cadaveric surgery to position the cutting wire around a tibia and calcaneus. A wire saw operating system was built that was successfully used to cut the tibia and calcaneus. ConclusionA MIS bone-cutting system was successfully designed, manufactured and used in a cadaver study showing that safe minimally invasive bone-cutting is feasible for two bone types with minimal damage to the surrounding tissue. Design optimization is needed to stabilize the compliant Nitinol needle during wire saw positioning and to allow cutting of bones with smaller diameters.

A study on the characteristics of intelligent sawing system for band saw

A study on the characteristics of intelligent sawing system for band saw

Study of size-related sensitivity of surface acoustic wave sensor towards particulate matter sized particles using finite element and experimental methods

To investigate the potential of using a surface acoustic wave sensor to measure both particulate matter (PM) concentration and size distribution, a forced-vibration model of a coupled particle–SAW system with interfacial excitation was built using the finite element method. The model shows different behaviors of the coupled vibration between mass loading and elastic loading regimes. The calculation of the frequency change of a 260 MHz SAW perturbed by different sized starch particles in the elastic regime is in agreement with our previous experiment, proving the validity of the model. The impact of different parameters, including the particle size, contact size, and material, on the particle–SAW interaction was investigated for understanding the perturbation mechanism of real particles. Wheat flour and talcum powder particles were measured by SAW experimentally, resulting in positive and negative frequency change, respectively. The experiment shows that SAW has different sensitivities toward particles with different size distributions and morphologies. The size-related sensitivity property of SAW could be used for building an instrument that is capable of monitoring both PM concentration and size distribution.

The effect of operational parameters on diamond tools of frame sawing system: Wear characteristics and optimization in stone processing

A series of sawing experiments was carried out to investigate the effect of operational parameters on the wear characteristics of diamond segment. And the wear mechanism of diamond segment was studied through micro-morphology. The analysis presented that the wear mechanisms of segment metal matrix are mainly attributed to abrasive wear and erosion wear, the wear mechanism of diamond particles mainly includes cleavage fracture caused by the impact load and abrasion caused by scratching. The effect of sawing parameters on the wear rate of segment matrix is consistent with that of diamond particles. The wear resistance of segment matrix increases with the increase of the proportion of diamond particles with micro-fractured and complete crystalline shape, and decreases with the increase of the proportion of diamond particles with macro-fractured and pulled-out. Furthermore, the predicted model was established to evaluate the segment wear per unit by using Design Expert software, and the optimum sawing parameters obtained as a result of the optimization was investigated to provide some guidance for the processing of the enterprise.

Estimation of Power Consumption in the Circular Sawing of Stone Based on Tangential Force Distribution

Circular sawing is an important method for the processing of natural stone. The ability to predict sawing power is important in the optimisation, monitoring and control of the sawing process. In this paper, a predictive model (PFD) of sawing power, which is based on the tangential force distribution at the sawing contact zone, was proposed, experimentally validated and modified. With regard to the influence of sawing speed on tangential force distribution, the modified PFD (MPFD) performed with high predictive accuracy across a wide range of sawing parameters, including sawing speed. The mean maximum absolute error rate was within 6.78%, and the maximum absolute error rate was within 11.7%. The practicability of predicting sawing power by the MPFD with few initial experimental samples was proved in case studies. On the premise of high sample measurement accuracy, only two samples are required for a fixed sawing speed. The feasibility of applying the MPFD to optimise sawing parameters while lowering the energy consumption of the sawing system was validated. The case study shows that energy use was reduced 28% by optimising the sawing parameters. The MPFD model can be used to predict sawing power, optimise sawing parameters and control energy.

A Comparison between SAW and WIM Systems on Highways.

A Comparison between SAW and WIM Systems on Highways.

Efecto del sistema de aserrío tradicional en las características de la madera de encinos

El proceso de aserrío de encinos se considera una fase importante de su industrialización y de la calidad de la madera generada. Se analiza el control de calidad del proceso de aserrío, el sistema de corte tradicional con el radial y su efecto en los coeficientes de aprovechamiento, en los tiempos de procesamiento y en la proporción de dimensiones en anchos de la madera generada. Se utilizaron trozas de Quercus laurina, Q. candicans y Q. acutifolia, que se procesaron en un aserradero banda de 8 plg de ancho, con sierras tradicionales para pino. La variación del corte (St) fue de 3,93 mm, que se considera alta y refleja una mala calidad del aserrío, la media fue de 25,36 mm y la dimensión óptima de corte de 28,71 mm, la diferencia indica que un porcentaje considerable de las tablas producidas (80 %) no se puede clasificar en el espesor de la categoría de 3/4 plg. Los coeficientes de aserrío del sistema tradicional fueron de 55,83 % y en el radial de 52,31 %. El tiempo de aserrío para procesar 1 000 pies tablas en el sistema tradicional fue de 73 minutos y en el radial de 103 minutos, lo que representa un 41 % más del tradicional. Con el sistema se aserrío radial, se generó una proporción alta (77 %) de tablas angostas (4 plg y 6 plg), y un porcentaje bajo (23 %) de tablas con anchos mayores de 8 plg. Con el aserrío tradicional, las proporciones se invierten significativamente, para los anchos mayores a 8 plg representaron un 88 %.

Antibody-based SAW sensor for the detection of explosives

A robust and sensitive method for the detection of the explosive trinitrotoluene (TNT) was developed. The detection limit was determined to be around 0.5 µg/L. The fast signal response of less than 1 minute shows that this approach is suitable for security and other time-critcal applications. In addition, the very low cross-reactivity highly reduces the number of false-positives in relation to competing techniques, including sniffer dogs. Due to the multianalyte ability of the SAW system, several explosives might be detected in parallel.

DETERMINAÇÃO DO RENDIMENTO DE MATÉRIA-PRIMA DE Eucalyptus benthamii Maiden & Cambage POR MEIO DE DIFERENTES MÉTODOS DE DESDOBRO

RESUMOO objetivo deste trabalho foi determinar o rendimento da matéria-prima de Eucalyptus benthamii, por meio dos desdobros tangencial e radial, além da classificação das toras quanto à presença das rachaduras de topo. A classificação das toras quanto às rachaduras foi realizada por meio da análise visual, em que era aplicado um conceito conforme a intensidade do defeito. Posteriormente, as toras foram separadas em duas classes diamétricas (20 a 25 e 25,1 a 30 cm) e processadas em três sistemas de desdobro (tangencial em bloco, radial e tangencial em bloco com face curva), sendo cada tratamento composto por três repetições com 10 toras cada um. Na análise estatística dos dados de rendimento, foram aplicados o teste de Kolmogorov Smirnov, a Análise da Variância e o teste de Tukey. Nos resultados, foi observado que a maioria das toras da classe de menor diâmetro apresentou intensidade mediana, enquanto na maior classe diamétrica a intensidade foi baixa. Os rendimentos médios líquidos encontrados foram de 43,5% e 39,2% nas classes inferior e superior, respectivamente, os quais foram influenciados pelas rachaduras das peças e pelos destopos. Observou-se que o desdobro tangencial em bloco e em face curva foram os métodos que apresentaram maior aproveitamento em madeira serrada na classe de 20 a 25 cm, enquanto na classe de 25,1 a 30 cm o sistema tangencial em bloco e radial foi equivalente.

The Motion Control of Profile Milling Flying Saw

Profile milling flying saw is one of the most advanced flying saws in the modern world, its tracking system driven by servo motor and its sawing system using profile milling method. This flying saw has many advantages, such as simple control system, less jamming signal, higher dimensional accuracy, flat section and convenient operation. Since the profile milling flying saw was launched, it has been put into a wide applications. The paper gives a brief introduction of the working principles of tracking system and makes a specific analysis of its motion. The movement patterns of saw cutting round pipes and square pipes are given in the sawing system and the mathematical models of saw cutting square pipes are established by analysis. In fact, the methods mentioned above have been used in practice. The dimensional accuracy of sawing welded pipe has reached the requirements of British BS standards and come up to the world advanced level.

Incorporation of Granite Waste from Diamond Wire Sawing Process into Cement Matrix Concrete

As one of the world leading producers of natural stones for ornamental purpose, mainly marble and granite, Brazil also generates an increasing amount of corresponding wastes. Several alternatives have locally been proposed for the application of these wastes, including the incorporation into cement matrix concretes. In the present work a granite waste, generated by a sawing system composed of sintered diamond in the form of cylindrical beats attached to a steel wire, was incorporated into a cement matrix to be used as building construction concrete. These cement concretes incorporated with up to 30 wt% of granite waste were evaluated in terms of mechanical and chemical properties as well as their environmental impact. The results indicated that 20 wt% incorporation would be a limit for a concrete with acceptable technical characteristics and safe environmental risks.