circular saws
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Author(s):  
В.И. Мелехов ◽  
И.И. Соловьев ◽  
А.В. Емельянов ◽  
Е.В. Сазанова ◽  
Т.В. Тюрикова

Широкое применение круглопильных станков в лесопильной и деревообрабатывающей промышленности обусловлено их высокой производительностью, простотой, надежностью конструкции, низкой энергоемкостью. Для повышения полезного выхода пилопродукции применяют тонкие пилы. Существенным недостатком, ограничивающим использование таких пил, является их недостаточная жесткость и устойчивость во время работы. Для повышения изгибной жесткости круглой пилы применяются щелевые, роликовые, аэростатические и электромагнитные направляющие. Большинство направляющих создают сопротивление вращению диска пилы. К недостаткам круглопильных станков следует отнести механические потери при передаче крутящего момента от двигателя диску пилы. Колебания диска круглой пилы во время работы являются еще одним недостатком тонких круглых пил, которые снижают качество обработки древесины, приводят к поломкам пил и повышенному уровню шума. Для увеличения надежности узла резания, стабилизации диска пилы во время работы, уменьшения колебаний пильного диска предложено использовать линейный асинхронный дугостаторный двигатель (ЛАДД), ротором в котором является сама круглая пила. Для проверки разработанной математической модели ЛАДД с круглой пилой в качестве ротора была создана экспериментальная установка. Целью работы явилась экспериментальная оценка математической модели и анализ рабочих и механических характеристик ЛАДД, характеристики холостого хода и короткого замыкания двигателя, зависимости мощности и cos ϕ от скольжения. Экспериментально установлено влияние электропроводности диска пилы на эффективность ЛАДД. Для увеличения тягового усилия предложено нанести на боковые поверхности диска пилы материал с высокой электропроводностью (медь). Проведенный эксперимент показал существенное увеличение тягового усилия для диска пилы с покрытием медью. Установленная экспериментально величина магнитной индукции в воздушном зазоре ЛАДД показала корректное совпадение с результатами расчетов по разработанной математической модели. The circular saws are widespread in sawmill and woodworking industry due to their high productivity, simplicity, design reliability, and low energy consumption. Thin saws are used to increase the effective yield of sawn timber. The insufficient rigidity and stability during operation of such saws limit their use. Slotted, roller, aerostatic and electromagnetic guides are applied to increase the bending stiffness of a circular saw. Most such guides create resistance to the rotation of the saw blade. Mechanical losses during the torque transmission from the motor to the saw blade is one of the circular saws disadvantages. Another disadvantage of thin circular saws is vibration of the circular saw blade during operation, which reduce the quality of wood processing, lead to the saw crashes and increased noise levels. It is proposed to use a linear induction arc-stator motor (LIASM), implementing the circular saw is the rotor, to increase the reliability of the cutting unit, stabilize the saw blade during operation, and reduce the oscillations of the saw blade. The experimental setup was created to analyze the developed mathematical model of a LIASM with a circular saw as a rotor. The aim of the work is the experimental evaluation of the mathematical model and the analysis of operating and mechanical LIASM characteristics, idling and short-circuit characteristics of the motor, the dependence of power and cos ϕ on slip. The influence of the saw blade electrical conductivity on the efficiency of the LIASM has been experimentally established. It was proposed to apply a material with high electrical conductivity (copper) on the side surfaces of the saw blade to increase the tractive effort of the drive. The carried-out experiment showed a significant increase in the tractive effort for a copper-coated saw blade. The experimentally established values of the magnetic induction in the air gap of the LIASM showed good coincidence with the calculated results from the developed mathematical model.


Wood Research ◽  
2021 ◽  
Vol 66 (4) ◽  
pp. 678-688
Author(s):  
ANKA OZANA ČAVLOVIĆ ◽  
IVAN BEŠLIĆ

Given the carcinogenicity of hardwood dust, the aim of this study was to determine the effectiveness of the photometric method for different types of woodworking machines and its application in determining the mass concentration of inhalable dust for raw and dry hardwoods. In addition to the optical part of the device, the input part of the measuring device contains the Institute of Occupational Medicine (IOM) inhalable dust filter holder. This correlation of gravimetric and photometric methods in determining the dust mass concentration showed that photometry underestimates the mass concentration measured gravimetrically. The results of this study recommend the application of a correction factor 2 for a timber band saw and a correction factor 3 for circular saws in determining the mass concentration of hardwood dust by the photometric method. It was showed that photometry can be used if the correction factor of the optical device has been previously tested for specific wood processing place.


2021 ◽  
Vol 13 (9) ◽  
pp. 1781-1788
Author(s):  
Zhao-Long Zhu ◽  
Wei-Hang Dong ◽  
Xiao-Dong (Alice) Wang ◽  
Xiao-Lei Guo ◽  
Zhan-Wen Wu

This work deals with the noise generated from sawing processes of medium density fiberboard, where special attention was given to the changes in sawing noise at different cutting conditions when using circular saws with varied radial slots. The experimental results gave the following insights: The noise level in idling is positively related to the spindle speed. According to the noise power spectra, whistling noise is found during sawing processes, which is mainly caused by self-excited vibration of saw, and it had directivity. Furthermore, the radial slots have a different positive contribution to the noise reduction during idling, but has limited effect on the noise in cutting. In order to reduce the noise pollution induced by sawing, it was proposed to use circular saws with radial slots and copper plugged in its bottom for sawing of medium density fiberboard, in respect to low noise level and avoiding whistling noise.


Author(s):  
O. A. Makarova ◽  
A. A. Zhdanov ◽  
R. I. Arzhukhanov ◽  
E. O. Siukova

This publication deals with the issue related to the study of the heat distribution in the tooth of a saw with a modified geometry, taking into account the frequency of the process of cutting cold rolled metal with circular saws.


Author(s):  
A. I. Bannikov ◽  
O. A. Makarova ◽  
R. I. Arzhanov ◽  
E. O. Siukova

This publication deals with the issue related to the study of the heat distribution in the tooth of a saw with a modified geometry, taking into account the frequency of the process of cutting cold rolled metal with circular saws.


2021 ◽  
Vol 3 (1 (111)) ◽  
pp. 14-20
Author(s):  
Oleksandr Okhrimenko ◽  
Vyacheslav Vovk ◽  
Serhii Maidaniuk ◽  
Yuliia Lashyna

To predict the workability of a tool structure at the design stage, it is necessary to calculate the parameters of the cut layer when this tool is used because the cut layer’s size determines the strength and dynamic characteristics of the cutting process. It is known that the size and shape of the cut layer are affected by the allowance cutting scheme embedded in the tool design. Therefore, the parameters of the cut layer with the tool must be investigated taking into consideration the actual shapes and location of the cutting edges of the tool teeth and the cutting scheme with individual teeth. Existing analytical dependences on determining the thickness of the cut layer do not take into consideration the group arrangement of the teeth, which have a different shape and location of their cutting edges. Therefore, a procedure for determining the thickness of the cut layer analytically has been proposed, using the example of circular saws with multidirectional teeth while taking into consideration the patterns in the arrangement of the cutting edges of individual teeth and the real movements of the tool during its operation. The proposed procedure makes it possible to determine the parameters of the layer cut with the tool at both constant and progressive allowance cutting schemes. One can also specify the parameters of the cut layer at any time of the tool’s operation and analyze the change in the shape of the slice in time. Based on the analysis of the parameters of the cut layer, it has been established that saws with multidirectional teeth do not work with the entire width of the cutting edge but only in its part, whose share does not exceed 55 % of the width of the tool. The procedure reported here could be used to determine the loading of the cutting tool part with a more complex cutting scheme, which also includes tools that are operated by the form-generating method


Procedia CIRP ◽  
2021 ◽  
Vol 101 ◽  
pp. 142-145
Author(s):  
Sunny Singhania ◽  
Mohit Law
Keyword(s):  

2021 ◽  
Vol 111 (01-02) ◽  
pp. 2-7
Author(s):  
Tobias Tandler ◽  
Dina Becker ◽  
Rocco Eisseler ◽  
Thomas Stehle ◽  
Hans-Christian Möhring

Der klassische Kreissägeprozess ist begrenzt durch die Größe des Werkstückes im Verhältnis zur Größe des Werkzeuges. Durch die Möglichkeit das Werkstück rotieren zu lassen, kann das Kreissägen auch bei größeren Werkstücken eingesetzt werden, da der benötigte Vorschubweg reduziert wird. In dieser Studie werden beide Verfahren bei gleichem Werkstück und ähnlichen Parametern gegenübergestellt, indem die jeweils erreichbaren Schnittoberflächen und die Produktivität analysiert werden.   The classic circular sawing process is limited in terms of the size of the workpiece relative to the size of the tool. By letting the workpiece rotate, it is possible to use circular saws to cut larger workpieces, as the required cutting path is reduced. The present study compares both methods based on the same workpiece and similar parameters, analyzing the achievable cutting surface.


BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 1029-1041
Author(s):  
Ján Kováč ◽  
Pavol Harvánek ◽  
Jozef Krilek ◽  
Tomáš Kuvik ◽  
Ján Melicherčík

An analysis was conducted of the effects of cutting conditions in the cross-cutting of wood using circular saws. Gradual wear of the saw blade cutting wedges impacted the entire cutting process. Two different types of circular saw blades were used. One blade type featured sintered carbide tips and 54 saw blade teeth, whereas the other had high-speed steel with 56 teeth; both saw-blades were 600 mm in diameter with a rake angle of 20°. The two wood species were spruce (Picea abies) and beech (Fagus sylvatica). During sawing, the timber was fed at a velocity of vf = 6 and 12 m·min-1. The cutting speed (vc) was set at 60 m·s-1, 70 m·s-1 and 80 m·s-1. The saw blades were coated with three types of PVD coatings. The least energy intensive saw blade was a sintered carbide-free saw blade with a coating (AlTiN) at a displacement speed of 12 m·min-1 and cutting speed of 60 m·s-1 with a power of 1310,63 W. Any change of a saw blade considerably affected torque for all the wood species, so a particular type of saw blade will always have an impact on torque. Other parameters distinctively and individually influenced the process of wood sawing.


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