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Effect of Number of Saw Blade Teeth on Noise Level and Wear of Blade Edges during Cutting of Wood


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The effect of varying the number of saw blade teeth while transversally cutting beech (Fagus sylvatica L.) wood on the noise level and saw blade lifetime between two sharpenings was tested. The experiment was carried out with raw beech wood samples with dimensions of 25 x 100 x 1000 mm and circular saw blades with cemented carbide tips (24, 40, and 60 teeth). The saw blade diameters were identical (D = 250 mm), as were the cutting wedge angle geometries (α = 15°, β = 60°, γ = 15°). The saw blades were selected based on commonly used blades (in the Czech Republic and Slovakia) for the transversal cutting of the given wood species. Neither the cutting speed (vc = 62 m/s) nor the feed force (Fp = 75 N) were changed during the cutting process. The results suggest that the number of saw blade teeth is an important factor that affects the noise level of saw blade during sawing as well as the wear of cutting edge.
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Kvietková et al. (2015). “Noise during wood cutting,” BioResources 10(1), 1657-1666. 1657
Effect of Number of Saw Blade Teeth on Noise Level and
Wear of Blade Edges during Cutting of Wood
Monika Kvietková,a Milan Gaff,a Miroslav Gašparík,a,* Richard Kminiak,a and Anton
Kriš b
The effect of varying the number of saw blade teeth while transversally
cutting beech (Fagus sylvatica L.) wood on the noise level and saw blade
lifetime between two sharpenings was tested. The experiment was
carried out with raw beech wood samples with dimensions of 25 x 100 x
1000 mm and circular saw blades with cemented carbide tips (24, 40,
and 60 teeth). The saw blade diameters were identical (D = 250 mm), as
were the cutting wedge angle geometries (α = 15°, β = 60°, γ = 15°). The
saw blades were selected based on commonly used blades (in the
Czech Republic and Slovakia) for the transversal cutting of the given
wood species. Neither the cutting speed (vc = 62 m/s) nor the feed force
(Fp = 75 N) were changed during the cutting process. The results
suggest that the number of saw blade teeth is an important factor that
affects the noise level of saw blade during sawing as well as the wear of
cutting edge.
Keywords: Noise level; Circular saw blade; Wear of cutting edge; Number of teeth; Beech wood
Contact information: a: Department of Wood Processing, Faculty of Forestry and Wood Sciences, Czech
University of Life Sciences in Prague, Kamýcká 1176, Praha 6 - Suchdol, 16521, Czech Republic;
b: SOLIDSTAV Co. Ltd., Kukučínova 9, Košice, 04001, Slovakia;
* Corresponding author:
Circular saws are used in many different industries for countless applications. As
a result of saw usage, an inherent hazard exists to the hearing of workers in the vicinity of
the machines, which generate noise of a particularly objectionable quality. Operators of
circular saws have an obligation, under law, to take all practicable steps to reduce the
noise emissions of these machines through engineering means. Management must also
ensure that workers that are not immediately involved in the saw operation are isolated
from the hazardous saw noises. Good reductions in noise levels are achievable. On
certain saws, the noise level can be reduced to below 85 dB (A); this aids in protecting
the operators. On other operations, it is impractical to achieve such reductions, and
hearing protection will also have to be worn.
Wood cutting with circular saws plays a very important role in both wood
processing and furniture industries (Koch 1985). The most frequently used type of tool
for cutting of wood and wood-based materials is, undoubtedly, a circular saw blade (Fig.
1). Blades of this kind are designed for portable circular saws, joinery saw benches,
format saws, cutting centers, edgers, and other saw types as well as round timber cutting
and firewood cutting circular saws. The greatest advantage of the cutting process with
circular saw blades is being able to achieve maximum cutting speed (up to 100 m/s)
Kvietková et al. (2015). “Noise during wood cutting,” BioResources 10(1), 1657-1666. 1658
(Prokeš 1980; Plester 1985). A circular saw blade without anti-noise grooves was utilized
in this study (Fig. 1a).
Moreover, circular saw blade fabrication and maintenance are simple in
comparison with other cutting tools (frame saw blade or band saw blade). Additionally,
circular saw blade replacement and setup in machines, consisting of the blade setting on
the spindle and its locking by a nut, are simple. In most machines, the circular saw blade
is fastened between two flanges, whose diameter should be equal to 1/3 of the saw blade
diameter. The flanges partially eliminate lateral blade vibrations. No further adjustment
of the proper tool in the machine is needed (Lisičan 1988, 1996).
Circular saw blades are always designed for a particular purpose (Fig. 1) (Pabiš
1999; Xu et al. 2001). In the wood processing industry, a circular saw machine is very
common and is used for longitudinal and transversal cutting of wood and wood-based
materials with large surfaces, for timber edging, structural joints, etc. (Mikolášik 1981;
Buda et al. 1983).
Fig. 1. Different saw blade designs: a) blade without anti-noise groove, b) blade with four grooves
around its outer perimeter, and c) blade with copper element inside a groove around its outer
During the process of cutting wood and wood-based materials with circular saws
(CS), two simultaneous interactions occur: the main rotational movement of the saw
blade (SB), and a linear shift of the blade (Beljo-Lučić and Goglia 2001). The saw blade
cutting edge moves at a constant cutting speed (vc) following a circular trajectory. During
the cutting process, the SB rotational movement and linear velocity of feed (vf) create a
cycloid trajectory. The cutting speed (vc) is several times greater than the value of vf.
Therefore, for cutting kinematics analyses, a part of the kerf in the wood is deemed a
circular arc (Cho and Mote 1979).
Another factor is the critical rotational speed of circular saw blade. This speed
represents the maximum rotation speed in which at circular saw blade sustained in a
stable phase. After exceeding of this critical speed, the circular saw blade cannot resist
transversal forces and becomes unstable, which is manifested, among other things, by
increasing the vibrations and noise level (Taki et al. 1975; Kimura et al. 1976; Hattori
and Noguchi 1992; Beljo-Lučić and Goglia 2001; Schajer and Wang 2002; Orlowski
2005, 2007; Kopecký and Rousek 2012).
Knowledge of the blade interaction phenomena is very important for optimizing
the machining process. The proper cutting process depends on various factors that
Kvietková et al. (2015). “Noise during wood cutting,” BioResources 10(1), 1657-1666. 1659
strongly affect such outputs as machined surface quality, cutting process energy, and
noise level (Prokeš 1982).
Most studies of parameters influencing cutting forces and power requirements
have been conducted at constant wood moisture (Konishi 1972; Steward 1984; Aquilera
and Martin 2001; Bučar and Bučar 2002).
The cutting process noise level does not affect the process that generates chips,
but it significantly affects staff health and safety. There is therefore a need to eliminate
any potential risk to which the employees are exposed. The knowledge of mutual
interactions of the mentioned factors and the proper cutting process constitutes an effort
to approximate optimum outcomes while keeping process costs low and maximizing
efficiency, purposefulness, and economy concerns while simultaneously observing
occupational health and safety (OHS) at work rules (Mikleš et al. 2010).
In the past, the wood processing industry has disregarded the fact that increasing
the machine running speed and the mechanization of the operation increase the noise
level (Wasielewski and Orlowski 2002; Chen and Chang 2012). Also, an acoustically
improper design of the external walls of production halls makes the noise level increase.
Until recently, tool design was primarily based on performance and the machined surface
quality. However, the fact that the tool is the primary source of noise has been neglected
(Prokeš 1985; Cheng et al. 1998).
Changes in the blade body resonance can be achieved through proper design,
thereby affecting its noise level and noise frequency. Saw blade design aims to reduce
noise levels using various shapes of grooves, both peripheral and within the inner section.
The groove diversity affects the blade strength parameters to maintain stability and safety
during cutting.
Trim saws belong to the group of machines with the maximum noise level, at
approximately 100 to 110 dB (A). Examples of trim saws include strippers, band saws,
and four-siders. As far as the physiological impact of noise on humans, it is known that
after long-term exposure in an environment with a noise level of approximately 85 to 110
dB (A), an individual will likely suffer hearing loss (Janoušek 2005; Žiaran 2005).
The aim of this work was to determine the influence of number of teeth of circular
saw blades on noise level during transversally cutting of beech wood. The transversal
cutting was carried out with circular saw blades at firm cutting speed (vc = 62 m/s) and
feed force (Fp = 75 N).
Samples of European beech (Fagus sylvatica L.) from the Poľana region, east of
Zvolen, Slovakia, were used for the experiment. Radial-sawn samples (Fig. 2) were made
from beech timber 30 mm thick, with various widths. Samples were selected to have
minimal knots and similar annual ring slopes. After cutting and length shortening, the
boards were dried and conditioned to 12 ± 2% moisture content under the following
conditions: relative humidity (ϕ) = 65 ± 3% and temperature (t) = 20 ± 2 ºC, thereby
being ready for further equalizing, thickening, and shortening processes. Test samples (60
to 80 pieces) were cut into dimensions of 25 × 100 × 1,000 mm (thickness, width, and
length). The number of test samples was specified in accordance with the tool edge
Kvietková et al. (2015). “Noise during wood cutting,” BioResources 10(1), 1657-1666. 1660
lifetime. The test sample dimensions for the experiment were designed with respect to the
function of the machinery and cutting conditions in a manner allowing data collection
regarding edge blunting while cutting the test samples.
Fig. 2. An overview of cross-sections of wood types
The boards were cut with a sliding mitre saw, GCM 10S PROFESSIONAL
(Robert Bosch GmbH, Germany). See Table 1 for saw technical parameters.
Table 1. Mitre Saw Parameters
Bosch GCM 10S Professional
Tool input (W)
Idle rotational frequency (min-1)
Cutting capacity at 45° chamfer (mm)
87 x 216
Cutting capacity at 45° declivity (mm)
53 x 305
Chamfer adjustable angle left / right (°)
Declivity adjustable angle left (°)
Saw blade maximum diameter (mm)
Flange diameter (mm)
Mounting hole diameter (mm)
Three PREMIUM (EXTOL, Czech Republic) circular saw blades, with diameter
250 mm and thickness 2.2 mm, with cemented carbide tips were used for transversal
cutting of the beech samples. The cemented carbide edge lifetime is 30 to 50 times longer
than that made of tool steel.
A digital noise meter SL - 4011 (Lutron Electronic Enterprise Co., Taiwan) was
used to measure noise levels. The circular saw blade noise level was determined in
accordance with ISO 9612 (2009). The proper measurement of the noise level during the
transversal cutting process was carried out at idle state and load running (i.e., cutting).
The noise meter was placed on an insulated tripod 100 cm from the measured blade and
150 cm above the floor in the operator's workplace (Fig. 3). The measurement within the
required noise exposure value of the running machine was ensured by means of
measurement automatic mode setup on the noise meter. This value falls within the
"Upper Operative Value of Exposure" inside the LAEX, (LAEX - normalized level of noise
exposure) value of 80 to 137 dB (A) for 8 h. Sign “(A)” means A-weighting which is
defined in the International standard IEC 61672 (2003) relating to the measurement of
sound pressure level. A-weighting is applied to instrument-measured sound levels in an
effort to determine the relative loudness perceived by the human ear.
Kvietková et al. (2015). “Noise during wood cutting,” BioResources 10(1), 1657-1666. 1661
Fig. 3. Illustration of saw blade noise level measurement: (1) circular saw blade, (2) noise level
meter, and (3) tripod
Once the electric motor was switched on, the shaft with the attached circular saw
blade was started. The measured noise values were evaluated using ANOVA analysis,
mainly by Fisher’s F-test, in STATISTICA 12 software (Statsoft Inc., USA).
The cutting edge loss (wear) between two sharpenings was considered the blade
lifetime index. Such loss reached its maximum value when the wood burned during the
cutting. A digital microscope DMBA 210 PC/ (Motic, China) with built-in camera was
used to evaluate the wear of the cutting edge. On each circular saw blade, the certain
number of saw teeth, having approximately the same initial blunting, were selected and
marked (6 teeth for 24-teeth, 10 teeth for 40-teeth and 15 teeth for 60-teeth circular saw
blade, respectively). After the cutting, marked teeth were measured again in order to
detect blunting, and of these values, the average value was calculated. The number of
cuts identifies the amount of cuts made with the saw tool without showing wear signs.
During this phase, the tool does not require treatment of the edge (tool edge lifetime
between two sharpenings). Once the edge lifetime was exceeded, the wear increase in
time was significant and not adequate for saw performance.
Based on the comparison of the results measured for the individual blades (Fig. 4)
with teeth numbers of 24, 40, and 60, it is clear that the highest noise levels occurred for
the 24-teeth circular saw blade. There were no significant differences in noise level
differences for sawing with the 40- and 60-teeth blades up to 6,400 cuts. For these two
blade types, a statistically significant difference was seen at 6,400 or more cuts.
At the beginning of the measurements for the 24-teeth blade, the idle run noise
value was 95.5 dB (A). The average first cut noise level was 97.9 dB (A), whereas, at the
end of cutting, the average noise level was 105.9 dB (A). This represents a statistically
significant increase in the noise level. The noise level increased exponentially from 0 to
3,000 cuts. Subsequently, the noise level did not change, as shown in the linear portion of
the diagram from 3,000 to 6,600 cuts, after which it increased exponentially up to 7,600
cuts. The cutting of wood with this saw blade was stopped at 7,600 cuts because the
beech wood samples were burning and blade re-sharpening was necessary. At this
Kvietková et al. (2015). “Noise during wood cutting,” BioResources 10(1), 1657-1666. 1662
number, the difference in the average noise level values between the first and the last cut
was 8 dB. As the cutting edge withdrew, the cutting was stopped for the individual blades
at the mentioned number of cuts.
Fig. 4. Measured saw blade noise level course as a function of the number of cuts for circular
saw blades with various numbers of teeth
At the beginning of the measurements for the 40-teeth blade, the idle run noise
value was 96.3 dB (A). The average first cut noise level was 97.3 dB (A), whereas at the
end of cutting, the average noise level was 105.1 dB (A). This represents an important
difference. The noise level increased exponentially from 0 to 1,600 cuts. Subsequently, it
became linear approaching 6,000 cuts. A statistically significant increase was apparent
from 6,200 to 11,600 cuts, afterwards increasing exponentially up to 12,200 cuts. The
saw blade cutting was stopped at 12,200 cuts because the beech wood samples were
burning. At this number, the difference in average noise level values between the first and
last cut was 7.8 dB (A).
At the beginning of the measurements for the 60-teeth blade, the idle run noise
value was 96.2 dB (A). The first cut average noise level was 97.0 dB (A), whereas, at the
end of cutting, the average noise level was 104.2 dB (A). This represents a statistically
significant difference. The noise level increased exponentially from 0 to 2,800 cuts.
Subsequently, the noise level did not significantly change up to 7,000 cuts and then
increased exponentially up to 8,050 cuts. Cutting with this saw blade was stopped at
8,500 cuts. At this number, the difference in the average noise level between the first and
the last cut was 7.2 dB (A).
In our experiment, we investigated the noise level by using a circular saw blade
without anti-noise grooves, while the majority of previously published work, such Droba
as Svoreň (2012), Beljo-Lučić and Goglia (2001), as well as Cho and Mote (1979),
focused on circular saw blades with these anti-noise-grooves. They found that the
average noise level, during a transverse sawing, is in the range from 93 dB to 104 dB.
Results obtained by our experiment are also within this range.
Kvietková et al. (2015). “Noise during wood cutting,” BioResources 10(1), 1657-1666. 1663
Badida et al. (2010) explored the occupational environmental noise level for
material cutting with circular saws. Their findings confirmed our results. The saw blade,
despite its anti-noise modifications and other measures, will exhibit a noise level
exceeding the LAEX upper operative exposure value of 85 dB (A) for 8 h. Therefore,
measures should be adopted to protect hearing pursuant to the Directive of the European
Parliament and of the Council No. 2003/10/ES. Authors Heisel and Kuolt (2004) also
reached this conclusion.
As shown in Fig. 5, the blade with the longest cutting ability, i.e., the longest edge
lifetime, was the 40-teeth circular saw blade. Paradoxically, the 60-teeth circular saw
blade exhibited less cuts although its blunting was higher than that of the 40-teeth blade.
Low blunting of the 60-teeth circular saw blade can be explained by the fact that blades
with higher number of teeth (i.e., with smaller gap between teeth) are used for thin
materials (with a minimum of 1 tooth in engagement). Generally, the following rule
applies: for harder materials, the saw blade should contain a greater number of teeth. This
is because with greater number of teeth and cutting speed, the cut becomes more accurate
and cleaner.
Unambiguously, the shortest lifetime and greatest wear were seen in the 24-teeth
circular saw blade. This finding can be explained because circular saw blades with
smaller numbers of teeth (i.e., with a greater gap between teeth) are used mostly for
thicker materials (with a maximum of 4 teeth in engagement), and for longitudinal cutting
of softwood species.
Fig. 5. Wear of cutting edge as a function of the number of cuts and various numbers of teeth
Therefore, the 40-teeth circular saw blade was the best for the process of beech
wood transversal cutting on a crosscut miter saw. This saw blade provides the best
relationship between blunting and lifetime.
Pernica and Rousek (2001) reported that circular saw blade with number of teeth
60 has about 10% greater durability than saw blade with 72 teeth. Even our results
confirm the fact that the circular saw blade with a lower number of teeth (40) has about
35% greater durability than saw blade with 60 teeth.
Kvietková et al. (2015). “Noise during wood cutting,” BioResources 10(1), 1657-1666. 1664
1. Based on the results, the influence of the number of saw blade teeth on the noise level
during sawing can be deemed statistically significant. It was found that for saw blades
with fewer teeth, the noise values were greater.
2. For saw blades with 40 and 60 teeth, no significant difference in the measured noise
level was shown. The difference increased after 6,400 cuts, as the difference in the
measured noise level values increased with increasing number of cuts.
3. Concerning edge lifetime, the blade with the fewest number of teeth had a
substantially shorter lifetime. This was evident in the blade blunting and formation of
burnt areas on the cut surfaces. The longest edge lifetime was found for the 40-teeth
saw blade. For this saw blade, the burnt areas caused by the blunting started to appear
after the 12,200th cut. In the case of the 60-teeth blade, no burnt areas appeared after
8,000 cuts to the degree that they appeared with the 24-teeth blade. However, tool
blunting resulted in an increase of both cutting shift and cutting resistance values.
The authors are grateful for the support of the Internal Grant Agency of the Czech
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Article submitted: November 18, 2014; Peer review completed: January 7, 2015; Revised
version received and accepted: January 20, 2015; Published: January 26, 2015.
... Although woodworking machine operators are exposed to a considerable number of harmful factors (Kvietková et al. 2015;Rogoziński et al. 2015;Ratnasingam et al. 2016), it is widely known that the mechanical processing of wood or wood-based materials using circular sawing machines, planing machines, and spindle moulders can involve a dangerous phenomenon called workpiece kickback (OSHA 3157 1999;HSE 2014;Dąbrowski and Górski 2018). Kickback is an uncontrolled rapid movement of a workpiece or part of it in an improper direction (e.g., opposite to the feed direction), which causes a direct hazard to the operator and other persons (or machines) in the vicinity. ...
Mobile shields at woodworking machine workstations were considered in this work as part of a protection and accident prevention system. A shield design based on an aluminium frame is proposed. The results of the experimental tests demonstrated the high efficiency of material kick attenuation using the mobile shields, irrespective of their position and the filling used. Operational tests on the mobile shields were performed in a woodworking shop, which confirmed their usefulness and made it possible to supplement the conclusions with interesting observations concerning their dimensional and visual features, among other things.
... They revealed that the wear of the cutting edge depends on the cutting conditions as well as the mechanical properties of the processed material. Factors for wood processes are more numerous than for metals e.g., moisture content, defects (knots), wood species, annual rings, etc. (Klamecki 1979;Orlicz 1988;Kminiak et al. 2015Kminiak et al. , 2016Kvietková et al. 2015;Górski et al. 2019;Nasir et al. 2019). For frozen beech band sawing, Siklienka et al. (2015) found that stellite tipped teeth had significantly higher wear resistance in comparison to swaged steel teeth. ...
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Thin lamellae, corresponding to the layer components of structural glued members, i.e., 2-ply or 3-ply glued flooring, can be manufactured in re-sawing operations of kiln-dried wood blocks or in wet technologies, which currently seem to be more common because of the shorter drying time. The re-sawing process in wet technology is conducted on dedicated thin-cutting band sawing machines with stellite-tipped band saws. The goal of this research was to demonstrate the capacity of surface production (m 2 / tool life) of visible layers of oak engineered flooring composites in a function of both a new band saw and a re-sharpened band saw blade. Additionally, the state of teeth of each band saw blade was examined at the end of the tool life. A series of cutting tests were performed in sawmill production conditions. The conducted tests revealed that a three times higher capacity of surface production was obtained for the new tool compared to re-sharpened tool. Additional microscopic observations of some re-sharpened teeth showed deformed plastic characteristics.
... It described the difference between the natural frequency of the CSB and the CCSB. 10 where f UCSB and f CCSB are the natural frequency of the CSB and the CCSB, respectively. ...
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Sawing is the most common process applied in the primary and secondary machining sectors. Unfortunately, circular saw blades (CSBs), as the main tool for sawing, will generate excessive noise in the idling and processing, affecting the user's health and the workpiece surface quality. Hitherto, numerous studies have modified the body structures of CSBs for noise reduction. Its challenge is to reduce the CSB’s stiffness and bearing capacity. Here, a novel composite coating circular saw blade (CCSB) was proposed indirectly improving material damping properties. Subsequently, the frequency response characteristics and harmonic acoustics of CSBs were analyzed by the finite element (FE) simulation. Results suggested that the CCSB can present a notable noise reduction ability. It was found that the peak value of the radiation noise for CSBs is mainly concentrated around the sawtooth passing frequency (SPF). By the analysis of the vertical field, the CCSB disorganizes the original sound pressure level (SPL) field due to the dissipation of shear energy, improving the original SPL distribution. The proposed analysis method of the CCSB can provide theoretical guidance for design, optimize low-noise CSBs and improve the processing environment in the future.
... The prolong use of machines and hand tools causes students and trainers to be in a noisy environment, hence, exposing them to adverse effects of noise exposure. Similar to the metal fabrication program, the noise emitted depends on the type and thickness of the material [52,64,65]. Among the types of wood used for training at this institute are Nyatoh, Rubberwood, Meranti, Balau, Pinewood and Merbau. ...
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The use of various machines, equipment and power tools at TVET Institute causes the institute’s environment to be exposed to noise hazards that are similar to the industry. However, not much data has been published regarding noise exposure at TVET institutes. This study was carried out to document the noise exposure of work activities training in public TVET institutes in Malaysia that implement skill training programs in metal fabrication, furniture manufacturing and automotive maintenance. The identification of excessive noise, task-based noise exposure monitoring and source measurement was conducted. The noise contribution from each work activity to the daily A-weighted noise exposure level and sound pressure level emitted by machines and equipment was documented. The findings of this study recorded 20 activities with task-based noise contribution to the daily A-weighted noise exposure level between 75.3 dB and 95 dB. Based on the findings, the training environment at the TVET institutes has a risk of operating with excessive noise. The documented data can be used in planning the implementation of suitable noise control measures in TVET institutes.
... The lack of machine maintenance also contributes to waste production. A blunt saw can leave burnt marks on the surface of the wood (Kvietková et al., 2015). Sanding is required to remove the burnt marks. ...
Conference Paper
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Malaysia's furniture manufacturing industry is made up of small and medium enterprises (SMEs), which contribute significantly to the country's economy. One major issue that these SMEs face is sustainable manufacturing: lowering throughputs and increasing production efficiencies. The study aims to improve the efficiency of producing a learning tower; a furniture product by an SME called Industerior Design by implementing material flow analysis (MFA) to monitor production throughputs. The MFA was used to compare two different learning tower designs (Design A and B). The most sustainable design was determined based on the MFA. A cause-and-effect analysis was also carried out using the Ishikawa fishbone diagram to identify potential causes of production inefficiencies. Both designs were proven to have the same processes involved and the same waste stream generated; however, Design A produces four learning towers from a single wood plank with 15.5% waste generated, while Design B produces only two towers with 44.6% waste generated. Of the waste generated by both designs, 60% from Design B was recyclable, while for Design A only 25% was reusable. Inefficiencies can be caused by a lack of skilled workers, a lack of or infrequent maintenance of equipment, or the design of the product itself. When the amount of recyclable waste that can be used for other future projects was considered, it was determined that Design B was more sustainable in the long run. MFA is thus thought to be a simple but powerful tool that can be easily implemented by SMEs in designing out waste from their products as the furniture industry moves toward more sustainable manufacturing and a more circular economy.
... In addition, Pangestu et al. [92] conducted cutting experiments by using helical edge cutting tools, their results showed that the helical edges provide lower noise emissions compared to the conventional edge (0 • ), and the noise level decreased with increasing the inclination angle of cutting tool edges. Kvietkova et al. [93] studied the influences of a number of teeth on noise level and edge wear during the sawing process. The results showed that the noise value of the saw blade with less teeth was larger. ...
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High-speed cutting technology has become a development trend in the material processing industry. However, high-intensity noise generated during high-speed cutting exerts a potential effect on the processing efficiency, processing accuracy, and product quality of the workpiece; it may even cause hidden safety hazards. To conduct an in-depth study of noise in high-speed cutting machining, this work reviews noise sources, noise collection and numerical recognition, noise control, and condition monitoring based on acoustic signals. First, this article introduces noise sources, noise signal acquisition equipment, and analysis software. It is pointed out that how to accurately classify and recognize the target signal in the complex high-speed machining environment is one of the focuses of scholars’ research. Then, it points out that a computer achieves high accuracy and practicability in signal analysis, processing, and result display. Second, in the aspect of noise signal processing, the characteristics of noise signals are analyzed. It is pointed out that accurately analyzing the characteristics of different noise source signals and adopting appropriate methods for identification and processing are the necessary conditions for effectively controlling and reducing the noise in the process of high-speed cutting. The advantages and applicable fields of artificial intelligence algorithms in processing mixed noise source signals with different frequency characteristics are compared, providing ideas for studying the mechanism of noise generation and the identification of noise sources. Third, in terms of noise control, a detailed overview is provided from the aspects of the treatment of the noise source that contributes the most to the overall noise, the improvement of the tool structure, the optimization of cutting parameters, and the analysis of contact factors between the tool and the workpiece. It provides an effective way for noise control in the process of high-speed cutting. In addition, the application of acoustic signals to condition monitoring is also thoroughly analyzed. The practical application value of condition monitoring based on acoustic signals in high-speed machining is highlighted. Finally, this paper summarizes the positive significance of noise research in high-speed machining and identifies key problems and possible research methods that require further study in the future.
... Krilek et al. (2016) observed that the number of saw blade teeth had a significant effect on noise emission. This observation was also confirmed by Kvietková et al. (2015). Durcan and Burdurlu (2018) noted that decreasing the blade number led to higher noise emission, while Çota et al. (2019) reported that noise emission increased with increasing feed speed. ...
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Background: Noise produced during machining of wood materials can be a source of harm to workers and an environmental hazard. Understanding the factors that contribute to this noise will aid the development of mitigation strategies. In this study, an artificial neural network (ANN) model was developed to model the effects of wood species, cutting width, number of blades, and cutting depth on noise emission in the machining process. Methods: A custom application created with MATLAB codes was used for the development of the multilayer feed-forward ANN model. Model performance was evaluated by numerical indicators such as MAPE, RMSE, and R2. Results: The ANN model performed well with acceptable deviations. The MAPE, RMSE, and R2 values were 0.553%, 0.600, and 0.9824, respectively, in the testing phase. Furthermore, this study predicted the intermediate values not provided from the experimental study. The model predicted that lower noise emissions would occur with decreased cutting width and cutting depth. Conclusions: ANNs are quite effective in predicting the noise emission. Practitioners relying on the ANN approach for investigating the effects of various factors on noise emission can save time and costs by reducing the number of experimental combinations studied to generate predictive models.
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.
Conference Paper
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Background: Armillaria novae-zelandiae and A. limonea occur naturally as wood decay fungi in native forests in New Zealand. As pathogens they are responsible for significant root disease in trees and shrubs in plantations, crops and urban parks and gardens. A thorough understanding of their population dynamics entails knowledge of the spatial arrangement of their individual mycelia or genets. In previous work the distributions of vegetative compatibility groups (VCGs) of these fungi were mapped in an area of native forest prior to and after replacement by a young Pinus radiata plantation. With the advent of molecular technology, it has become possible to test species identities made earlier using culture techniques and to verify whether or not their VCGs, determined by incompatibility reactions between paired cultures, represent distinct individual genets. Methods: Stock subcultures of isolates representing each VCG were recovered from storage in order to obtain DNA. Extracted DNA was subjected to a polymerase chain reaction procedure (UP-PCR) using 11 universal primers to assess genetic variation between subcultures. Bands were scored as either present or absent for each primer-subculture combination and cluster analysis was undertaken by generating dendrogram trees to reveal genetic groupings among subcultures. Results: DNA cluster analysis divided subcultures of isolates into two species groups, A. novae-zelandiae and A. limonea, corresponding to identities determined through culture morphology. Within species, subcultures grouped into clusters that matched VCGs determined by earlier culture pairing. There was little indication of genetic variation within VCGs, except for one of A. limonea, which comprised two sub-clusters. Conclusions: The Armillaria species and VCGs identified by culture techniques in the laboratory were verified by independent molecular methodology. In general, the VCGs represent discrete individual genets or colonies in the field. Techniques that differentiate isolates based on differences in their DNA sequence provide a quick alternative to time-consuming laboratory culture methods for resolving population spatial structure. However, some complementary isolate pairing may be necessary when rationalising the significance of groupings in dendrogram trees.
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The sound pressure level of differently designed circular saw blades were investigated during idling. Nine blade samples were used: three differently designed blade bodies (without slots, with four radial slots, and with four slots with copper cork), each with three diameters (260,280, and 300 mm). The sound pressure level was measured at different rotational frequencies ranging from 25 to 65 rps in increments of 1 rps. Rubber damping rings 80mm in diameter and 0.3 mm thick were placed between the saw blade and the collars, and the emitted noise was measured. Because of the whistling sound the blades without slots emitted high sound pressure levels. There were no significant changes when rubber damping rings were used. The use of rubber damping rings on the samples with radial slots eliminates the whistling noise. The saws with copper corks did not emit a whistling noise at all, and their aerodynamic noise was 2–3 dB (A) lower than the aerodynamic noise of the saws with radial slots. The relation between sound pressure emitted by the damped idling saw and peripheral velocity can be described by the power function with the exponent value between 4.8 and 5.2.
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silvatica) and spruce (Picea excelsa). The machining process was carried out on a shaper with specific devices. The concerned variables were: cutting depth, feed rate and cutting speed. The mean chip thickness and cutting width were constant. The machining process was done in two different ways: conventional and climb cutting; thus it was possible to compare both working directions with the same machining parameters and watch their influence on the cutting forces, the power consumption and the surface roughness. The most important variables on the cutting forces are depth of cut, wood density and feed direction. With regard to power consumption, it was detected that the most important variables were cutting speed, feed direction, depth of cut and wood density. It was further demonstrated that the measured and calculated power have a very good correlation, and that the cutting forces can be determined by the calculated power. Thus, if cutting power is measured for a specific condition of wood and machine, the cutting forces can be estimated. The surface roughness was very homogeneous in all the tests. The better machining process was obtained when applying conventional cutting. Then the cutting forces, the power requirements and the roughness standard deviation reach smaller values.
This paper proposes a two-phased procedure for the optimum design of circular diamond saw blades. In Phase one, an accurate finite element (FE) model representing an actual saw blade is acquired by incorporating experimental and finite element analysis (FEA) frequencies to update the blade FE model. In Phase two, shape optimization of the radial slots on the blade, based on the updated geometrical parameters obtained in Phase one, is performed to maximize the frequency separation between the FEA results and the saw’s operational speed, in an attempt to reduce the possibility of structural resonance. The effectiveness of the proposed two-phased system is demonstrated by the successful implementation of several numerical examples.
To suppress the so-called whistling noise in idling circular saws, a circular saw with slots in the peripheral area of the blade has been widely used. However, the effect of the slots is uncertain because the natural frequencies of saws vary, even among saws even if they were designed to suppress the whistling noise. Therefore, we made two types of tungsten carbidetipped circular saws; one with the sawblade made of a high-damping alloy named Silentalloy (SIA) and one with the blade made of the common alloy tool steel (SKS5). The noise levels and the power spectra of these saws during idling and cutting were measured at rotational speeds from 1,000 rpm to 6,000 rpm. The minimum damping capacity required to suppress the whistling noise in an idling circular saw was measured using the characteristic of SIA that the damping capacity can be changed depending on the temperature of the heat-treatment. The circular saws made of SIA generated neither the whistling noise nor the low discrete noise caused by the sawblade resonance. Slots are not necessary in a SIA saw because the coefficient of thermal expansion of SIA is relatively small. In fact, the slots raised the noise level of the SIA saw slightly. The degree of scatter in the noise levels of SIA saws was low unlike that of the SKS 5 saws. The noise level of the SIA saw during cutting was reduced a few decibels at the operator's position. It was demonstrated that the minimum damping capacity required to suppress the whistling noise is in the vicinity of 0.07 in logarithmic decrement. In conclusion, the whistling noise can be suppressed completely if a sawblade is made of a high-damping metal such as Silentalloy.
An investigation is reported of the forces and energy in circular sawing and grinding of gray granite. Measurements were made of the forces and power over a wide range of sawing and grinding conditions. Calculated tangential force components were found to be much different than the measured horizontal force components for sawing, but the two forces were almost identical for grinding. The location of the resultant force was proportional further away from the bottom of the cutting zone with longer contact lengths. For sawing, the normal force per grain was nearly proportional to the calculated undeformed chip thickness. The G-ratios at different sawing rates reached a maximum value at the same intermediate undeformed chip thickness, which was attributed to a transition in the diamond wear mechanism from attrition to fracture at a critical normal force per grain. SEM observations indicated material removal mainly by brittle fracture, with some evidence of ductile plowing especially for grinding and to a lesser extent for salting. The corresponding fracture energy was estimated to constitute a negligible portion of the total energy expenditure. About 30 percent of the sawing energy might be due to the interaction of the swarf with the applied fluid and bond matrix. Most of the energy for sawing and grinding is attributed to ductile plowing. Analogous to recent studies on grinding of ceramics and glass, the power per unit width was found to increase linearly with the generation of plowed surface area per unit width.
The character of the dominant aerodynamic noise source for rotating rigid circular saws is concluded to be represented by a point dipole model. The source strength is directly dependent upon Reynold’s number and saw design. A theoretical model is presented for prediction of the farfield noise. Experimental measurement of the fluctuating lift force on particular tooth models was used to identify the dipole source and a hot wire anemometer, rotating with the saw, measured the tooth wake. The theoretical predictions of dipole noise dependence upon parameter variation are generally consistent with literature noise data.
The natural frequencies, aerodynamic noise, whistling noise, and self-excited vibration between the common circular saw with uniform thickness and the circular saw with step thickness (thin on its outer part and thick on its inner part) were researched during idling. The natural frequencies of the circular saw with step thickness increased with an increase in the thickness and in the radius of the thick part. The frequencies of the circular saws with step thickness (thick at the inner part) were higher than that of the thin circular saw with a uniform thickness of 0.5mm. The aerodynamic sound pressure level induced from circular saw teeth increased with an increase in the tooth thickness. The whistling noise and self-excited vibration easily occurred in the thick circular saws (1.5, 2.0, and 2.5mm). The whistling sound pressure level and the vibration amplitude increased with an increase in the thickness of the saw. None of the designed circular saws with step thickness generated whistling noises or self-excited vibration during idling.
in the process of circular rip-sawing of wood tissue. The specific cutting force represents a complex interaction between the geometry of the blade, the physical and mechanical properties of the tissue and the direction of cutting, i.e. the rotating angle of the tool. The analyses carried out confirm the appropriateness of the definition of the specific cutting force as the parameter independent of the cross-sectional geometry of the chip, i.e. independent of the technological parameters. The results of the analysis of the relation between the tangential component of the cutting force and the feed velocity, which at invariable values of the entrance and exit rotating angle of the tool directly determines the mean thickness of the chip, confirm the hypothesis on an exponential relation between the said variables. In the case of invariable geometric parameters of the tool, the specific cutting force is constant, while the relation between the cutting force and the technological parameters is merely a consequence of the influence of the parameter of cross-sectional area of the chip f hm . For this research wood of two tree species was used, namely celtis wood (Celtis zenkeri Engel.) and manilkara wood (Manilkara fouilloyana Aubrev et Pellegr.).
In frame sawing machines, where a saw frame is driven by a crank mechanism, an inertial force produced by the saw frame cyclic motion significantly affects the machine foundation and also the saw frame driving system. This paper discusses the question how these serious using difficulties in machine performance can be eliminated. The authors present the principle of operation of the hybrid dynamically balanced saw frame driving system with the kinetic energy accumulator connected in parallel. The findings of numerical analysis are: this solution allows us to eliminate changing loads of the driving system and permits a reduction of the mass and dimensions of the machine, to eliminate a huge and expensive foundation, and to increase the working speed.