Effects of Loom Speed, Insertion Air Pressure, and Yarn Type on Fabric Air Permeability: Case Study on Air Jet Loom

Te air permeability of the fabric is afected by the type of yarn used, the loom speed, and the amount of air pressure delivered by the relay nozzles. In this study, 21 Ne of ring and rotor spun yarns were used as a weft in an air jet loom. Loom speed and left-and right-side relay nozzles pressure in a range of 400–600 RPM, 2–4 bar, and 3–6.5bar, respectively, were taken as additional factors. To develop and analyze the experiment, a full factorial design was used. It was observed that the air permeability of rotor spun weft yarn fabric’s is greater than ring spun weft yarn fabrics. Furthermore, when the speed of the loom increased and the left-and right-side relay nozzles air pressure decreased, the fabric’s air permeability increased and vice versa.


Introduction
Te garment's thermo-physiological properties are determined by its air permeability, moisture management, and heat transfer regulation properties [1].Te biophysical properties of a fabric afect its ability to transport gaseous substances and sweat, have a substantial impact on the thermal protection of the human body, ensure the maintenance of an adequate body temperature, and determine its resistance to atmospheric conditions [2].Air permeability can be described as the amount of air, measured in liters, that can be passed through 100 cm 2 (10 cm by 10 cm) of fabric in one minute at a pressure diferential of 10 mm hydrostatic head [3,4].It is a very essential fabric quality that has a signifcant impact on its use in some technical and apparel applications [5].Air sacks, parachutes, athletic clothing, underwear fabrics, t-shirts, socks, and industrial and residential flters are examples of products where air permeability is crucial to performance [6,7].Many researchers have been looking at the majority of the variables that afect the air permeability of the fabric.Te most frequent factors include weave type, fabric cover factor, fabric thickness, fabric porosity, yarn type (spun or flament), yarn twist, yarn size (linear density), yarn crimp, fber cross section, and the quantity of fnish and coating given to the fabric [8][9][10][11][12][13].Te woven fabric with simple harmonic air permeability is shown in Figure 1.
Tis study is primarily concerned on the efects of weaving parameters and yarn types on fabric air permeability.Weft insertion parameters in an air-jet loom are critical elements that infuence fabric air permeability indirectly by causing weft yarn twist loss during insertion.Weft yarn twist loss is directly afected by weaving parameters such as loom speed and insertion air pressure levels [15].According to several scholars, when the loom speed increases, the loss of weft yarn twist decreases, but when the applied air pressure for insertion increases, the loss of weft yarn twist increases [15][16][17].However, the level of twist loss varies depending on the type of weft yarn used because diferent spinning methods produce yarn with distinct properties [18].When compared to rotor spun yarn, ring spun yarn has more hair and a lower volumetric content [19].As a result of this, ring-spun weft yarn has a larger twist loss than rotor-spun weft yarn [20].However, the indirect impacts of yarn type and weaving conditions on fabric air permeability have not been investigated.Tus, our work is primarily focused on the issue at hand.Design Expert 11 software has been used to develop the experimental runs as well as analyze the results.

Materials and Methods
2.1.Materials.For this experiment, 21 Ne of 100% cotton yarns were spun on ring and rotor spinning machines.Table 1 shows the yarn parameters that were measured and have been used as a weft in the air jet loom for the production of required samples.Both yarns and fabric samples were made in Bahir Dar Textile Share Company, Bahir, Dar, Ethiopia.Furthermore, ring spun yarn was used as a warp to produce woven fabric.Te machines used in this research work are mentioned in Table 2.

Fabric Sample Preparation.
Te fabric was manufactured in accordance with the specifcations shown in Table 3. Te same type, density, and quantity of ends of warp yarn were used throughout the entire sample productions.
At the Bahir Dar Textile Share Company spinning factory, the same count of ring and rotor spun yarns were produced.Characterization and recording of the outcomes were carried out on the produced yarns.Design Expert 11 was utilized to create the fully factorial design experiment for the production fabric sample.Te variables that were considered were the type of yarn, loom speed, left-and rightside relay nozzles.Afterwards, the planned design was followed in the creation and execution of the trials of fabrics.Te air permeability of the resulting fabric sample was then assessed and examined.
Te experiment has been prepared using Design Expert 11 (full factorial design (FFD)), with the actual factor levels given in Table 4 serving as the basis for execution.Because weft yarn demands a higher starting acceleration, the air pressure at the main nozzle was kept constant at 4 bars throughout the process of manufacturing the requisite samples.Based on the actual value of the listed factors, sixteen runs were developed, as shown in Table 5.In the experiment, −1 (green shaded) denoted ring spun weft yarn and +1 (orange shaded) denoted rotor spun weft yarn.

Characterization of Fabric Air Permeability Properties.
Te rate of air fow moving perpendicularly through a known area under a specifed air pressure diferential between the two surfaces of a woven fabric [21].Te fabrics were examined using an air permeability tester (model FX-3300) as illustrated in Figure 2. A circle of fabric is clamped into the tester, and the air pressure on one side of the fabric is made diferent by using a vacuum.Ten, the air fows from the higher-pressure side through the fabric to the lowerpressure side.Based on this rate of air movement, the fabric's air permeability is computed.Ten replicates for both the ring and rotor yarn fabrics were conducted.For evaluation, the ES ISO 9237: 2015 standard was used [22].

Yarn Diameter.
According to [23], numerous yarn qualities can be measured with the USTER ® TESTER-5.Two parallel laser beams that illuminate the yarn from both sides create an optical feld around it as it passes through.Te two light beams are at 90-degree angles.According to ES 136, standard 1000 m of yarn were taken from the cone, and the diameter and hairiness of the threads were measured.In addition, fve replications were performed to reduce mistakes.To determine the diameter of the yarn after weaving, the weft yarn was unraveled from the body of the fabric and its diameter was evaluated.

Yarn Twist.
Yarn twist refers to the number of turns in a certain length of yarn.To determine the average twist of yarns, utilize the common untwisting retwisting method, which comprises untwisting the yarn until it has no twist and counting the number of spins back to the original twist level.Te number of twists loss was determined by unraveling the weft thread from the body of the fabric according to ISO 2016: 2015 with a gauge length of 500 mm and utilizing an electrical twist tester with untwist retwisting methods to compute the number of turns lost during weaving.Taking into account the direction given by [24,25] on both sides of the cloth, the 500 mm length of yarn was taken, which was 150 mm away from the selvage.Both samples were replicated ten times each.

Results and Discussion
As indicated in Table 6, the study utilized a predetermined combination of yarn type, loom speed, and air pressure.Sixteen fabric samples were produced using the air-jet weaving machine while maintaining the same values for the other variables.Te yarn twist loss and fabric's air permeability were assessed following sample conditioning at 65% RH and 20 °C for the analysis.

Weft Yarn Twist
Loss.Diferent researchers have confrmed [26][27][28][29][30] that the weft yarn loses its twists during the insertion procedure at the air jet loom.Te yarn's properties are among the most crucial elements afecting this twist reduction.Because of their distinct features, varieties of yarns show diferent twist loses.Figure 3 shows the twist loss of ring and rotor weft yarns that were generated under similar weaving conditions.For example, run 1 shows that ring and rotor spun yarn twist loses are woven at 600 rpm on the loom, with 2 bar air pressure at the left-side relay nozzle and 3 bar air pressure at the right-side relay nozzle.Run 2 also shows the twist loss result of ring and rotor spun weft yarns that were woven under 600 rpm loom speed with 4 bar on left-side relay nozzle air pressure and 6 bar on right-side relay nozzle air pressure, and these conditions were continued up to run 8. Tere is a noticeable increase in twist loss from run one to run eight for both yarns.In particular, the ring and rotor weft yarn twist loss rises by 50 to 121 TPM and 17 to 108 TPM, respectively, when the loom speed drops from 600 rpm to 400 rpm.Tis could be because a slower loom speed allows the weft yarn to remain in the shed for longer periods of time, allowing the yarn to release its potential energy and be betted by the insertion air pressure for a longer period of time.Te graph also shows that at a constant weaving condition there is a signifcant twist loss diference between rotor and ring spun weft yarns.Yarn-twisting technique is another determining element for weft yarn twist loss.Te outermost fbers are exposed to high stress in the ring spinning system [18,31].When this highly strained fber is allowed to rotate, the accumulated potential energy will cause it to simultaneously relax and lose its twists.In contrast, with rotor spinning, twist originates in the center and extends to the surface; hence, the highly stressed fbers are situated at the core that is shielded from untwisting of the yarn during insertions by loosely connected fber [18].

Impacts of Twist Loss on Yarn Voluminous.
As this experiment and other researchers observed, the weft yarn has a high twist loss, due to a special feature of the yarn and weaving parameters.Te voluminous nature of the yarn is afected by this twist loss.After the woven fabric's air permeability was examined, the diameter and twist loss of the individual yarns were measured after the yarns were unraveled from the body of the fabric.As shown in Figure 4, the outcome demonstrates that, when yarn twist loss grows, yarn diameter (voluminous) increases.Tis could be that when the highly compressed and stressed fbers release their turning efects, they become relaxed and the fbers align openly, increasing the diameter of the yarn.Tis suggests that yarn volume after weaving is a function of yarn twist loss.

ANOVA and Analysis of Fabric Air
Permeability.An ANOVA test was used to determine each factor's signifcance.Any terms are signifcant if the P value is less than 0.0500, whereas values greater than 0.1000 indicate they are not signifcant.According to the ANOVA test illustrated in Table 7, the model of air permeability has signifcance with a P value of 0.0001.Te associated coefcients' stronger signifcance is indicated by the smaller P value and larger F value.Te signifcance level of the model is too high.Te air permeability of the fabric was also signifcantly afected by linear terms of yarn type, loom speed, left-and right-side relay nozzles air pressure, interaction efects of left-and right-side relay nozzles air pressure, and interaction efects of loom speed with left-and right-side relay nozzles air pressure (all terms have a P value of 0.005).Te two remaining variables of the interactive efect (loom speed with left-side relay nozzles air pressure and loom speed with left and right-side relay nozzles air pressure) had no signifcant efect on the fabric's air permeability.Journal of Engineering 3 Te model that best fts the air permeability of the fabric is the one with a coefcient of adjusted (R 2 ) value of 0.9809, as indicated in Table 8.Tis suggests that 98.09% of the fabric's air permeability may be attributed to the component under investigation.Furthermore, they are fairly in agreement because there is less than a 0.2 discrepancy between the adjusted R 2 values of 0.9809 and the predicted R 2 of 0.9458.
Te scatter plots of the actual vs predicted values in Figure 5

Te Efects of Yarn Type, Loom Speed, and Insertion Air
Pressure on Fabric's Air Permeability.Te air permeability of a garment fabric is an essential factor of its comfort attributes.Its properties are altered by imputed material properties and processing parameters and conditions.Consequently, in this study, the efects of yarn type, loom speed, and left-and right-side relay nozzle air pressure on the air permeability of air jet-woven fabrics were investigated.When investigating the efects of each individual factor on the given response, the remaining parameters were held constant.

Efects of Yarn Type on Fabric Air Permeability.
Since the late 1960s, the textile industry has seen numerous interesting technological advances in spinning machinery.Te machinery designers developed diferent spinning machines to maximize production with higher quality.Tey supply rings, rotors, air jets, friction, and wrap spinning.
Tose spinning technologies produce yarns with unique features, especially in strength, uniformity, hairiness, voluminous, and others [32].Ring-spun yarn is recognized for its great strength and hairiness, whereas rotor spun yarn is known for its higher uniformity and volume [29,32,33].As observed section of weft yarn twist loss of this research work and other studies, because of their distinct characteristics, diferent twist loss is noticed when the two yarns are used as weft in an air jet loom [20].Tis twist loss has a signifcant efects on fabric mechanical and comfort properties [34,35].Te result shown in Figure 6 reveals that rotor-spun yarn fabric has more air permeability than ring-spun yarn fabric.At a constant weaving parameter (loom speed of 500 RPM, left-side relay nozzles air pressure of 3 bar and right-side relay nozzles air pressure of 4.75 bar), the air permeability of the ring spun weft yarn fabric is 77.96 cm 3 /cm 2 /s, while for the rotor is 82.4 cm 3 /cm 2 /s.Tis demonstrates that even if rotor-spun weft yarn has a bigger volume before insertion than ring-spun weft yarn, the situation is reversed after weaving because ring-spun yarn loses more twist than rotorspun weft yarn, resulting in a larger volume for the yarn and covering the space between the yarns in the fabric.It implies that the twist level has a substantial efect on the air permeability of woven fabric.At the same weft and warp density of the fabric, a low-twist yarn has a bulkier structure that can block the space between yarns and make it difcult for air to travel through it, whereas a highly twisted yarn binds all of the fbers together and creates an open fabric structure that allows for greater airfow.Scholars from various disciplines have agreed on this premise [36,37].Moreover, ring-spun weft yarn has more fringed fbers that fll the area between Rotor spun yarn Ring spun yarn  the yarns in the fabric and so prevent the passage of air through it, as further supported by Ahmad et al. [38].On the other hand, the rotor yarn surface has a wrapper fber that connects the bulk of the fbers to the body of the yarn.Tis opens up the fabric and allows more air to travel through.Terefore, twist loss is the function of woven fabric air permeability.

Efects of Loom Speed on Fabric Air Permeability.
Te air permeability of air-jet woven fabric and loom speed are directly correlated, as shown in Figure 7.In this graph, the actual air permeability of the fabric is 74 cm 3 /cm 2 /s at the slowest loom speed of 400 RPM.Te fabric's air permeability improves to 81.92 cm 3 /cm 2 /s when it reaches its maximum speed of 600 RPM.Moreover, the results in Table 6 show that, with constant left-and right-side relay nozzle air pressures of 4 bar and 6.5 bar, respectively, when the loom speed increased from 400 RPM to 600 RPM, the ring spun weft yarn fabric's air permeability increased from 70.32 to 82.95 cm 3 /cm 2 /s, while the rotor increased from 73.3 to 88.63 cm 3 /cm 2 /s.As studied by diferent scholars, in the spinning process, the yarn gains a high turning efect (potential energy), and when this yarn gets free time with betting pressure, it becomes untwisted; therefore, when the loom speed increases, the weft yarn stays in the opened shed for a shorter period of time, resulting in a low yarn twist loss [16,20,35].Consequently, with a fxed pick density of the fabric, when the yarn twist level increases (loss of twist lowers), the fabric's cover factor reduces and the fabric has a more open structure, which results in increased air permeability.Furthermore, as the loom speed increases, so does the warp yarn tension, causing the yarn to fatten at the locations of crossover between the two threads.Tis raises the cover factor of the fabric.Tis was also confrmed by diferent scholars [39,40].

Efects of Air Pressure on Fabric Air Permeability.
In an air-jet loom, the weft yarn is inserted by compressed air [27].Even though this insertion method boosts loom output, it has a negative impact on fabric quality.As shown in Figures 8(a) and 8(b), when the supply air pressure of both relay nozzles increased to the highest level, the fabric's air permeability decreased.For instance, when the left side relay nozzle air pressure increased from 2 bar to 4 bar with a constant of other factors, the fabric air permeability fell from 81.4662 cm 3 /cm 2 /s to 78.897 cm 3 /cm 2 /s.In the same way, when the right-side relay nozzle's air pressure increased from 3 bar to 6.5 bar, the fabric's air permeability reduced from 83.377 cm 3 /cm 2 /s to 76.986 cm 3 /cm 2 /s.Tis shows that the amount of twist loss increased as air pressure increased.It is due to the pressurized air beating the tip of the free end of the yarn to become untwisted.When the yarn loses its twist, it becomes bulkier.Te fabric's cover factor rises with Journal of Engineering increasing yarn diameter (bulkiness), which makes it more difcult for air to enter.Tis is more clearly seen in the air pressure at the relay nozzles on the right-side relay nozzles than on the left-side relay nozzles since the level of twist loss is highest on the right side.Terefore, the insertion air pressure and fabric air permeability are inextricably linked.

3D Factors Interaction Efects on Fabric Air
Permeability.Te simultaneous alteration of two or more components at the same time may have unexpected impacts on the reaction.Factorial designs are commonly used in studies involving several factors where it is necessary to investigate the combined infuence of the factors on a response [41].According to the ANOVA results, the interaction efect of left-and right-side relay nozzles air pressure on fabric air permeability is signifcant.Terefore, to analyze the impacts of two efects on a single response, a 3D response surface graph is required.Figure 9 depicts the relationship between fabric air permeability and the combined efects of left-and right-side relay nozzles on air pressure.At the lowest levels of left and right relay nozzles air pressure (2 and 3 bars, respectively), high air permeability of the fabric (96.86 cm 3 /cm 2 /s) was observed.However, when the values of the relay nozzles on the left and right sides were increased to their maximum values (4 and 6 bars, respectively), the amount of air transported into the fabric was at its lowest value (70.32 cm 3 /cm 2 /s).In addition, contour line in Figure 9 shows that the fabric's air permeability decreases as the air pressure in both relay nozzles increases.Tis is due to the phenomenon of twist loss.As proved, twist loss is a function of supplied air pressure.

Conclusion
In this study, the efects of yarn type, loom speed, and insertion air pressure on air jet-woven fabric's air permeability were explored.Yarn types have a considerable impact on fabric air permeability due to their distinct characteristics.On the other hand, loom speed and insertion air pressure afect the air permeability of the garment.

8
Journal of Engineering Te experiment revealed that the air permeability of rotor-spun yarn fabric is higher than that of ring-spun yarn fabric.With a constant weaving parameter (500 RPM loom speed, 3 bar air pressure on the left-side relay nozzles, and 4.75 bar air pressure on the right-side relay nozzles), the rotor's air permeability is 82.4 cm 3 /cm 2 /s and the ring spun weft yarn fabric's is 77.96 cm 3 /cm 2 /s.Nevertheless, loom speed has a signifcant impact in woven fabric air permeability.Te ring-spun weft yarn fabric's air permeability increased from 70.32 to 82.95 cm 3 /cm 2 /s when the loom speed increased from 400 RPM to 600 RPM with constant air pressures of 4 bar for the left and 6.5 bar for the right relay nozzles.Meanwhile, the rotor increased from 73.3 to 88.63 cm 3 /cm 2 /s.Moreover, there is an inverse relationship between fabric air permeability and insertion air pressure.Te fabric air permeability decreased from 81.4662 cm 3 /cm 2 /s to 78.897 cm 3 /cm 2 /s when the air pressure in the left-side relay nozzle was raised from 2 bar to 4 bar while maintaining other constants.Similarly, when the air pressure at the right-side relay nozzle was raised from 3 bar to 6.5 bar, the air permeability of the fabric decreased from 83.377 cm 3 /cm 2 /s to 76.986 cm 3 /cm 2 /s.

3. 4 .
Regression Analysis.A regression model has been developed to predict the fabric air permeability level.Te equation illustrated in equation (1) also demonstrates that the response (fabric air permeability) will vary by a percentage of the selected factor's coefcient value if one variable varies by one unit while the other variables stay constant.Te two kinds of yarn, loom speed, left-side relay nozzle, and right-side relay nozzle were taken into consideration when the model was being developed.Tis regression equation also indicates that the air pressure of the left-and right-side relay nozzles has a negative impact on the air permeability of fabrics, whereas the yarn type and loom speed have a benefcial infuence.Air permeability � +80.18 + 2.22A + 3.96B − 1.28C − 3.2D + 3.1CD show how well the model fts.Te fabric air permeability predicted values are shown on the y-axis, and the actual values are shown on the x-axis.Te predicted regression line is represented by the diagonal line, while the points surrounding it show the outcomes of 16 experimental fabric air permeability values.Because the values are close to the diagonal line, the model fts the data well.Given that almost all of the points are closest to the line, indicating a good correlation between the predicted and actual values of fabric air permeability.

Figure 4 :
Figure 4: Impacts of twist loss on yarn voluminous.

Figure 5 :Figure 7 :Figure 6 :
Figure 5: Graphs of predicted vs actual values of fabric air permeability.
side relay nozzles air pressure (Bar) (b)

Figure 8 :
Figure 8: Efects of (a) left side relay nozzles air pressure and (b) right side relay nozzles air pressure on fabric air permeability.
h t s i d e r e l a y n o z z l e s a i r p r e s s u r s id e re la y n o z z le s a ir p re s s u re (B a r )

Figure 9 :
Figure 9: Te interaction efects of left-and right-side relay nozzles air pressure on fabric air permeability.

Table 1 :
Te specifcations of the chosen yarn.

Table 3 :
Specifcations for a fabric sample.

Table 4 :
Factors' actual and coded levels.

Table 5 :
Te experimental design was developed by using the actual values of the variables.

Table 6 :
Te average test results of dependent variable.

Table 7 :
Te ANOVA of fabric permeability resistance.

Table 8 :
Fit statistics for fabric air permeability.