Murugesan M.* 1, Senthilkumar T.2 , Devika V.1, Kausicka B.1, Seshadri R. D.1, Shreepat G. M. K.1
1Department of Textile Technology, Anna University, Chennai 600 025, India
2ICAR-Central Institute for Research on Cotton Technology, Adenwala Road, Matunga East, Mumbai 400019, India
Mail to: firstname.lastname@example.org
Needle temperature is one of the main problems during the sewing of heavy thermoplastic materials. Higher needle temperatures can cause the damage of fabric as well as sewing thread. Many studies have been carried out to understand the parameters, which influence needle temperature. Understanding these parameters will help in minimizing the problem of needle heating. Needle heat is mainly influenced by the characteristics of the needle, sewing thread and fabric. The sewing machine process parameters and condition of the sewing machine also play a role in sewing needle temperature. Hence, the present research aims to study the effect of various fabric parameters and machine parameters on needle temperature. Fabrics were sewn in the sewing machine at a constant speed of 3500 rpm for several hours continuously in the laboratory as well in the apparel industry. The needle temperature was recorded with the help of an infrared pyrometer at time intervals of 30 minutes for 2 – 5 hours. The highest sewing needle temperature was recorded for the manmade fibre fabric. The needle-heating pattern has been graphically represented. The results obtained indicate that there is a significant influence on needle temperature.
Keywords: Needle Temperature, Sewing thread, Stitch per inch (SPI), fabric layers
Sewing is to be the most important activity in an apparel industry that ensures timely delivery of apparel goods. The apparel industry demands high speed, quality sewing in order to meet production demands. The materials that are usually sewn range from single and multiple ply synthetic fabric, plastic, and leather, which are thick, making the sewing conditions harder than ordinary sewing applications. Heat is generated during the sewing process because of friction between the needle and the cloth fibres. According to Howard and Parsons (1968), the amount of heat generated at the surface between the fabric and the needle depends upon the type of fabric, fibre, the yarn count, the needle size and shape, the needle surface finish, the sewing speed and the interrelationships of all these and other factors. Synthetic fabrics and synthetic blends are subjected to temperatures above their softening points and a melt or encrustation often adheres to the needle, filling the groove and eye and causing thread breakage. In heavy cotton and cotton-blended fabrics, the heat often damages the sewing thread, leave weakened seams if actual breakage does not occur. Similarly, Frederick and Zagieboylo (1955) have done the studies; untreated wool fabric generates the highest degree of needle heat. The needle heat generated is the result of needle and fibre friction and is related to surface characteristics of the fibre material and to density or tightness of the fabric, as well as the machine speed. There are several factors such as needle characteristics, fabric properties, sewing condition and sewing thread influence the temperature of the needle. Needle surface finish was found to be the most significant needle variable. In the course of garment manufacturing, for protective measures to prevent the thread strength reduction and/or breakage during sewing from the needle heat up, the different types of finishes can be applied over sewing thread according to the specific end use of apparel products .Finishing treatments reduce needle heat by reducing friction, making the fibres more slippery while the needle penetrates the fabric . Nickel, plain steel and chrome gave increasing temperatures in that order . Currently there are different surface finishes are available for sewing needles to reduce the friction and thus the temperature. The various finishes such as Matt finished needles, Chromium plated needles, and Nickel platted needles. There are two major variables responsible for the heat generation when the needle goes in and comes out of the fabric are (i) The maximum force needed to punch a hole into the fabric and (ii) The total energy required to form a stitch .
Table. 1 Fabric Specifications
|Samples||Fabric used||Weft count||Warp count||EPI||PPI||GSM||Weave|
The needle temperature increase with higher speeds is quite dramatic and could be represented fairly well by a linear relationship showing a temperature increase of 0.08°F/ rpm. Thus increasing the sewing speed from 2500 to 4500 stitches/min would cause a temperature increase of 160°F . Many efforts have been taken to analyze the needle heating problems, to understand the mechanism of needle heating, correlating the factors of needle characteristics, operation conditions and fabric properties to the peak temperature. This understanding is required so that measures can be taken to prevent damage to the fabric. The objective of this study is to how the needle temperature varies when various process parameters like type of fabric, SPI; number of fabric layers are varied. The needle-heating pattern with respect to time and the time taken by the needle to reach its peak temperature are also intended to be studied. This would help to know what would be the maximum heat generated and at what time it would reach its peak value while sewing in an apparel industry.
2. Materials and Methods
2.1.1 Fabrics Used for Study
Since the study required fabrics of different weave, GSM & thickness, a few fabrics made of 100% cotton, poly cotton & polyester were chosen. The fabric physical parameter details are given in Table 1. Sample 1 was tested at Colorplus Fashions Pvt.Ltd, Chennai, Tamil Nadu, India, sample 2 was tested at Vijay Enterprises, Chennai, Tamil Nadu, India, and the rest of the samples were tested at the laboratory.
2.2.1 Procedure adopted
The experimental setup was designed for accuracy of test results. The flow of air was restricted into the experimental setup. The pyrometer was set at distance of 10 cm from the sewing machine needle so that the all the readings are recorded from the same point. From the Table 1, Sample 1 was tested in Colorplus Fashions where the line was engaged in sewing a men’s formal pant, which involved single needle lock stitch, feed of arm, and overlock machines. Sample 2 was tested in Vijay Enterprises where the line was engaged in sewing a women’s casual shirt, which involved single needle lock stitch, feed of arm, and over lock machines. Sample 3 and sample 4 were tested at the laboratory where the number of layers was varied in case of sample 4 and the SPI was varied in case of sample 3. The samples were stitched using a single needle lock stitch machine continuously for 2-5 hours.
Single Needle Lockstitch Sewing Machine DDL- 8300 N Model 31234, Feed of arm, Overlock machine and TESTO 830-T1 Infrared non-contact pyrometer were used for the present studies. A Pyrometer measures the heat radiation from the surface of the needle.
2.2.2 Measurement of needle heat
In the industry the temperature of the sewing needles were recorded along the sewing line while they were sewing. Values were recorded at regular intervals of 30 min including the idle time using the infrared pyrometer. The position of the pyrometer was marked at every workstation so that the distance between the needle and the pyrometer was always constant. The name of the operation and the seam sewn were noted. The study was done for 3hrs individually at both the industries (Sample I & Sample 2). In the laboratory, the samples 3 & 4 were cut in desired dimensions. Each of the samples was sewn throughout its surface continuously. The fabric sample 3 was sewn continuously for 2hour by varying the SPI from 1-5 and the temperatures were noted for every 30 min. The fabric sample 4 was sewn continuously for 2hour by varying the fabric layers from 1-3 and the temperature was noted for every 30 min. The needle temperatures were noted down with the help of the infrared pyrometer, which was fixed at a distance of 10 cm from the needle. The temperatures were noted down in ºC. In order to analyse the effect of sewing thread and fabric on the temperature of sewing needle sample 4 was stitched for an hour without fabric and without sewing thread respectively. The readings were taken at 30 min time interval.
3. Results and Discussion
3.1. Needle temperature measured for Sample 1 (Colorplus Fashions Ltd., Chennai, Tamil Nadu, India)
The needle temperatures obtained through testing Sample 1 along the sewing line in Colorplus Fashions ltd. is given in Table 2. The line was engaged in sewing a men’s formal pant. From the above Table 2, it is evident that there has been a rise in the needle temperature of about 2-5˚C from the starting point. The maximum temperature change has been observed in the topstitching operation on the front & back panel, inseam and back rise using JUKI Single Needle Lockstitch machine. This is because the topstitching operation involves a number of layers over which a seam is formed. This increases the number of contact points between the needle and the fabric due to which the needle temperature rises. The side seam and inseam operations, which involves longer seam when compared to other operations, also shows a significant rise in temperature.
3.2 Needle temperature measured for Sample 1 (Colorplus Fashions Ltd., Chennai, Tamil Nadu, India)
The needle temperatures obtained through testing Sample 2 along the sewing line in Vijay Enterprises is given in Table 3. The line was engaged in sewing a women’s casual shirt. From the Table 3, it was observed that the increase in temperature in each operation is about 1-2ºC. As observed in the previous industry the maximum temperature rise was found in the top stitching operations at the sleeve, shoulder and button placket. However, the rise was not as high as observed in the previous industry. This might be due to the length of seam the involved. The seams are of shorter length in a women’s top when compared to a men’s pant. In all the other operations like collar, cuff, sleeve and placket attachment the rise in temperature is about 1-1.5ºC.
3.3 Effect of stitch per inch (SPI) on needle temperature (Sample 3)
The effect SPI on needle temperature is tested using sample 3 in the laboratory. The needle temperatures and the needle-heating pattern obtained through testing Sample3 are shown in figure 1. The SPI is varied from 1-5 while the rest of the parameters are kept constant. The number of stitches formed for each SPI from 1-5 (SPI 1:21, SPI 2: 11, SPI 3: 8, SPI 4: 6, SPI 5: 5). It was clearly observed from the figure 1 that the needle temperature increases as the number of stitches per inch increases, the similar observation also reported by Adnan & Antinin (2014) . This was because the number of SPM remains the same for any SPI. Only the length of seam sewn per minute varies. So the number of times the needle penetrating the fabric remains the same for any stitches per inch (1-5). Thus, the effect of SPI on needle temperature did not show any significant pattern.
3.4 Effect of fabric layers on needle temperature
An increase in the number of layers of fabric results in higher needle temperatures . The effect of number of fabric layers on needle temperature is tested using sample 4 in the laboratory. The needle temperatures and the needle-heating pattern obtained through testing Sample 4 are given in Figure 2. The number of layers is varied from 1-3 while the rest of the parameters are kept constant. It is observed from the Figure 2, that as the number of layers increases the temperature of needle also increases. The temperature increases almost 1ºC for the same period of time when the number of layers increases. This is because the area of contact increases as the number of layers increases. The maximum temperature reached when the number of layers was varied from 1-3 was 34.3, 35.4 and 35.8 respectively. The temperature is almost same when the number of layers was 2 and 3 but there is significant change when the number of layers was 1 and 3.
3.5 Effect of sewing thread and fabric on needle temperature
In general, heavier fabrics of the same type will generate higher temperatures, but there is no way to determine the sewing characteristics of a fabric from its structure and composition . The effect of sewing thread and fabric was analysed by stitching for an hour without fabric and without sewing thread on sample 4 respectively. The needle temperatures while sewing without fabric and without sewing thread along with the temperatures while sewing the same fabric with sewing thread for an hour. From the Figure 3, it was observed that there was no rise in needle temperature when sewn without fabric. There was only about 0.1-0.3ºC rise in the temperature, which cannot be considered as a rise as the atmospheric temperature also changes. However, from Figure 4 it was evident that there was a significant rise when the fabric was sewn without sewing thread. The friction between sewing thread and sewing needle does not rise the sewing needle temperature whereas the friction between the fabric and sewing needle does rise the temperature. Thus, it was evident from the observations that the effect of sewing threads on needle temperature is almost nil and the effect of fabric on needle temperature is significant.
The study has been made to correlate a few sewing parameters and the sewing needle temperature. The samples taken for study were cotton, polyester and poly cotton with varied GSM. The observations made in the industries showed that the there was a significant rise in the temperature in the top stitching operations which is due to more number of layers in the sewing operations. The needle, which was engaged in sewing longer seam, also showed higher rise in temperature. The observations made in the laboratory showed that the change in SPI does not show any significant pattern temperature rise, since the number of SPM remained the same and only the length of the seam sewn varied for a particular period. The needle temperature was rise linearly with increase in the number of layers of the fabric. This is due to the increase in contact points between the needle and the fabric. The needle temperature in the absence of fabric showed no increase in temperature and the needle temperature showed higher increase in the absence of thread for the same fabric. This shows that the thread does not have any effect on needle temperature whereas the fabric has a great effect on needle temperature.
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