Heat Setting Process Research Articles

The Effect of Air Humidity on the Performance of DC Link Capacitor Components

DC link capacitors (DCLCs) are key devices in converters. The relative humidity affects the performance of the elements of a DCLC. Currently, there are relatively few studies on the effect of relative humidity on the electrical characteristics of the elements of DCLCs during the production process. This study describes the effects and the control of the relative humidity in the production process. For this purpose, a DCLC component withstand voltage test platform and a DCLC component aging test platform were established. The voltage withstand tests were conducted during different processes and at different relative humidities, and life aging tests were conducted at different relative humidities and different storage times. The results show that after the winding and metal-spraying processes, the voltage withstand levels of the components stored at 30% RH, 60% RH, and 80% RH were very close to that of the components at 3000 VDC; after the heat-setting process, the voltage withstand levels of the components stored at 30% RH, 60% RH, and 80% RH showed a decreasing tendency compared with the level of the components at 3000 VDC. Regarding the samples, after the heat-setting process, stored at 30% RH and 60% RH for 24 h, 96 h, 168 h, 240 h, and 336 h and 2000 h of the aging tests, the capacitance decreases monotonically as the storage time is increased but never exceeds 3%, and the capacitance change decreases as the relative humidity increases. This study can provide important guidance for the humidity control of various processes in the production of DCLCs.

Analyzing the dyeing behaviour of easy dyeable and regular polyester by the influence of different heat-setting temperature

The heat-setting effects of easy-dyeable polyester (EDP) have been investigated by comparing it with regular polyester fabric (PES). Using XRD analysis, the crystallinity and amorphousness of the easy-dyeable polyester and regular polyester fabric were assessed after 45 s during heat-setting of EDP and PES at nominal temperatures (120, 140, 160, 180, and 200 °C). The heat-set of EDP and PES fabric were dyed separately and competitively at temperatures ranging from 100 to 130 °C using S-type (C.I. Disperse Red 167) and E-type (C.I. Disperse Red 60) dyes. The color strength (fk ) and dye uptake were found to be lower at the heat-setting temperatures of 180 °C for PES and 140 °C for EDP. To ascertain the impact of varying heat-setting temperatures on PES and EDP-dyed fabric, the dimensional stability and GSM were assessed. When the heat set temperature was raised from 140 °C, the EDP fabric showed greater dimensional stability. On the other hand, the dimensional stability of untreated PES fabric (−4.2% lengthwise) and GSM (111 g/m2) gradually stabilized when the heat-setting temperature increased. However, the color fastness rating has improved after applying the heat-setting process for PES and EDP at 180o C and 140 °C, respectively.

Numerical study on transport and deposition characteristics of particles associated with heat setting process in opposed jet flow field

The transport and deposition of particles accompanying the heat setting process in the opposed jet air supply system have a significant impact on the equipment safety. This paper used the Realizable k–ε model to simulate the flow field distribution of the impinging jet and the Lagrange method to track the trajectory of particles, by considering factors, such as jet velocity (7–13 m/s), oven temperature (413–473 K), and particle size (1–30 μ m ) changes, the instantaneous force process of particles was analyzed and their deposition mechanism was revealed. The numerical results have been well validated, with the root mean square error of within 10%. The results indicate that the flow field form of the opposed jet significantly affects particle placement on the surface of the air duct, the maximum turbulent vortex structure appears at the inlet of the air duct on both sides of the protruding nozzle, enhancing the capture of particles. Under the influence of gravity, the lower surface of the air duct becomes the main deposition surface, this phenomenon becomes more pronounced as the particle size increases and the maximum deposition rate difference between the upper and lower layers is 37%. The number of particles deposited on the rear end of the air duct is greater than that on the front end, and the deposition rate decreases with the increase in jet velocity. In the initial stage, a temperature gradient appeared in the machine room, which provided upward lift for the particles, resulting in more small diameter particles ( d p < 10 μ m ) depositing on the upper surface of the air duct. The results can provide theoretical support for the fire prevention and pollutant purification of equipment, such as heat setting machines.

Effects of Mechanical Stress on the Life and Insulation Performance of DC-Link Capacitors

Mechanical stress is a crucial factor affecting the life and insulation performance of DC-link capacitors (DCLCs). However, at present, there is a lack of long-term experimental observations on the effects of mechanical stress on the life and insulation performance of DCLCs. The element-winding process for DCLCs is carried out by winding metalized film on a reel and adjusting the various winding tensions and pressures according to performance requirements, usually with a winding tension coefficient (WTC) of kT = 1.5. The pull pressure of the winding machine on the film produces tension during the elements’ winding process, and the tension in the film grows after the heat-setting process. In this study, by adjusting the four tension coefficients of the elements in the winding process, which were 1.4, 1.5, 1.6, and 1.7, various winding tensions of the DCLC components were changed. Additionally, various heat-setting shrinkage tensions were appropriately generated by setting different heat-setting temperatures (HSTs). Relevant test platforms were established, and a life aging test, insulation resistance measurement, and withstand voltage test were performed on these DCLCs at different tension coefficients and HSTs. The obtained results reveal that the mechanical stress of DCLCs is affected by the parameters of the material itself, including the tension coefficient during the winding process and the HST. The winding tension affects the life of DCLCs, such that those with the highest tension (kT = 1.7) demonstrate the longest life at an HST of 105 °C, whereas samples with the lowest tension (kT = 1.4) exhibit the longest life at an HST of 110 °C. HSTs are capable of improving the lifetime of DCLCs. HSTs are also able to improve the withstand voltage capability of DCLCs, but the tension is not proportional to the withstand voltage capability of DCLCs. This research provides a suitable basis for further explorations of the life and insulation performance of DCLCs.

Modeling The Thermofixation Parameters Of A Lycra Fabric

This article describes the ideal conditions for heat-fixing a cotton-lycra-based fabric. Indeed, the heat setting process has an impact on the technical parameters of the fabrics, such as tensile strength, initiated tearing, elasticity and remanence. Knowing that fabrics containing lycras are delicate in terms of dimensional stability, the interest of this article is to contribute to the control of heat setting parameters with the aim of having optimal dimensional stability of fabrics. To do this, we considered 3 types of fabrics containing elastanes with different composition. From the tests and tests carried out, we obtained the ideal parameter values (including temperature and speed) for the heat fixing of fabrics.

Analysis of stentering and heat-setting on the structure and compression behavior of 3D mesh fabric using X-ray micro-computed tomography and microscopic modeling

Three-dimensional (3D) mesh fabric is a key component in ventilated car seats for its excellent cushioning and ventilating performance. It is produced by stretching an as-knitted spacer fabric with closed surfaces via stentering and fixing the mesh form via heat-setting. This paper analyzes the effect of stentering and heat-setting processes on the structures and compression properties of a typical and commercial 3D mesh fabric by using X-ray micro-computed tomography (μCT) and finite element (FE) models. The monofilament architectures of the fabric after knitting, stentering, and heat-setting are reconstructed from μCT scanning, and the structural evolution is quantitatively investigated in terms of global dimension change, curvature, and torsion. The results from μCT reconstructions demonstrate that stentering shortens, widens, and thins the fabric due to yarn transfer to shorten monofilament loops and lengthen spacer monofilaments, which are then dispersed, bent, and twisted to increase the curvatures and torsions. The FE simulations indicate that the global and local monofilament architecture deformation shifts the fabric compression mode from constrained post-buckling to concurrent tilting and post-buckling of spacer monofilaments, expanding the plateau stage and decreasing plateau stress. Heat-setting shrinks monofilament and therefore deteriorates its mechanical performance. The fabric is further thinned during the heat-setting process, which also further bends and twists spacer monofilaments to slightly decrease the plateau stress. The structures and cushioning performance of 3D mesh fabrics can be engineered by employing a proper stentering ratio followed by a heat-setting process.

Quantitative analysis of monofilament architecture in three-dimensional mesh fabric using micro X-ray computed tomography

Three-dimensional mesh fabric has been successfully installed in ventilated car seats due to its excellent cushioning and ventilating properties originating from a sandwich monofilament architecture. In this paper, a detailed structural analysis is presented of a 10.3 mm thick three-dimensional mesh fabric to better understand the structural features and mechanical behavior. A continuous monofilament architecture was reconstructed by using a filament centerline tracing technique and micro X-ray computed tomography data. The curvature, torsion, and length of a unit cell extracted from the monofilament architecture were calculated. Inflection points from the curvature and torsion curves were used to divide the continuous monofilament architecture into separate monofilament loops and spacer monofilaments. The monofilament loops are found to have similar maximum curvatures at their intermediate points between 1.5 and 1.8 mm−1, but the spacer monofilaments have discrepant maximum curvatures close to the ends between 0.3 and 0.75 mm−1. The monofilament loops are sinusoidally arranged with a sinusoidal torsion distribution at their ends ranging from 0.2 and 0.9 mm−1 due to the stretching and heat setting process. Spacer monofilament torsions vary nonlinearly from negative to positive and the maximum torsions are between 0.45 and 0.9 mm−1. The monofilament loops have a length of 3.07–3.90 mm, while the spacer monofilaments have a length of 10.94–12.54 mm. Spacer monofilaments within the unit cell differ in curvature, torsion, and length, so their contributions to fabric compression resistance should be different.

The Relief Effects of Thermoplastic Structured-Shrunken Yarns on Woven Fabrics

In this study, the heat-setting method which applied on thermoplastic-heat sensitive-shrunken yarns were experienced as an innovative relief effect in fabrics that formed with the weaving method. Also, numerical and visual values of these methods were determined, and in the conclusion part, their contributions according to design criteria were analyzed. In applications, woven fabric structure with singlelayer and weaving fabric structure with double-layer in bag structure in dobby and jacquard weaving techniques, heat-sensitive and nonsensitive yarns were used. As a result, it was observed that the positive results of the relief effects with the usage of thermoplastic structured-heat sensitive yarns and heat-setting process on the fabrics that woven with the three different weft yarn groups and four different patterns.

Sustainable Heat-setting Process in Stenter for Textile Industry

Knitting, dyeing and finishing are the main steps in knit fabric processing. In finishing, Stenter machine is used to dry and heat-setting of fabrics. Generally one step heating process is running in most of the knit industries where knit fabrics in wet condition pass through very hot chambers (80–200 °C) in stenter which needs to slow the machine speed to evaporate water completely and deliver low production ultimately. Instead of one step heating, in this research two steps drying process like simple steam heated roller drying before chambers at low temperature (50–80 °C) and then drying, heat setting at higher temperature (80–200 °C) in chambers successfully increase the speed of stenter as well as production. Fabrics characterization shows that the properties of predried fabrics remain unchanged.

Design and manufacture of three-dimensional auxetic warp-knitted spacer fabrics based on re-entrant and rotating geometries

Warp knitting technology is a fabric-forming technologies that is very suitable to fabricate three-dimensional (3D) auxetic fabrics due to its high efficiency and powerful pattern designing possibilities. In this study, two typical auxetic geometries, namely the re-entrant hexagonal network and rotating square solids, were selected as the design prototypes for the design and manufacture of 3D warp-knitted spacer fabrics. While two 3D warp-knitted spacer fabric structures with representative units of different sizes designed based on the re-entrant hexagonal geometry were manufactured by using a RD7 double needle bar Raschel machine with seven yarn guide bars, two 3D jacquard warp-knitted spacer fabrics with different base fabric structures designed based on the rotating squares geometry were fabricated by using a RDPJ4/2 double needle bar jacquard machine with two ground yarn guide bars and four jacquard guide bars. The Poisson’s ratios of these 3D warp-knitted fabrics in the course direction and wale direction were evaluated respectively through constant-rate tensile tests. The results revealed that the re-entrant hexagonal fabric structure with double chain stitches has auxetic behavior across a wide range of tensile strains along the course direction, while the rotating square fabric structure with elastic chain stitches as the base is auxetic within a narrow range of tensile strains along the wale direction. The study provides an alternative method to directly produce auxetic warp-knitted spacer fabrics through a single knitting process instead of using an additional post-compression and heat-setting process.

Structural Evolution of Polyglycolide and Poly(glycolide-co-lactide) Fibers during the Heat-Setting Process.

PGA and P(GA-co-LA) fibers applied as surgical sutures strongly depend on their microstructure. The structural evolution in both the relaxed and tensioned states during heat-setting after hot stretching, which included heating and postannealing, was investigated using in situ WAXD/SAXS and DSC techniques. We found that the fibers of both PGA and P(GA-co-LA) with 8% LA content under the relaxed state were more advantageous than the fibers under the tensioned state indicated by the larger crystallite sizes and unit cell parameters and the higher crystallinity. The mechanical properties of the samples increased after heat-setting. Heat-setting at 120 °C was more suitable for promoting the fiber properties, which can be ascribed to crystal formation and perfection. During the heating, the thermal expansion increased the unit cell parameters and the long period of PGA linearly, whereas the unit cell parameters of P(GA-co-LA) had an obvious turning point at 60-80 °C, and the long period showed a sudden decline in the temperature range of 60-80 °C, which was mainly the result of the discharge of LA units. The unit cell parameters and the long period of both PGA and P(GA-co-LA) decreased during the isotherm process due to crystal perfection. However, the P(GA-co-LA) decrease was more prominent than PGA because of the inclusion of LA monomers in the crystal structure of GAs.

Analysis of potential waste heat recovery from a stenter in a textile plant

The textile sector, an important economic driving force in Antioquia, Colombia, uses great quantities of thermal energy mainly produced by coal combustion, which holds enormous potential for recovery. One of the most common processes in a textile plant is heat setting, which uses a significant amount of thermal energy to adjust the properties of fabrics, such as shrinking, stiffness, pull strength, width, and stretching. In this study, we calculate the mass and energy balances of a stenter and propose a system to recover the energy available in its exhaust gases. The energy recovery potential in this heat setting process is 800.97 kW, which represents 87.2% of the total input energy. Additionally, we evaluate different heat exchangers to recover the available heat and present criteria to select them. Finally, thermosyphons, whose thermal efficiency was theoretically determined here, offer a promising alternative for heat recovery from actual stenters.

Effect of Knitting and Finishing Parameters on the Initial Young’s Modulus and Tensile Strength for Polyester Weft Knitted Interlock Fabric

75D/72f and 100D/96f polyester yarns were knitted to develop three kinds of fabrics with different densities (large, medium and small) on circular knitting machine (gauge E18). It was found that the strength of the fabrics increased with the increase of loop density, and the initial modulus of the fabrics also increased. In order to obtain better strength and lower initial modulus, the washing and heat setting process of the fabric were studied and explored. The strength and initial modulus of the three density fabrics of the two yarn specifications decreased after pre-washing. Finally, the lowest initial modulus (0.36 MPa at warp direction and 0.22 MPa at weft direction) were found in sample (sample no. 3–3) made of 75D filament in longest loop length under 140 °C heat setting. The weft strength and warp strength were 9.54 MPa and 5.28 MPa respectively.

Prediction of Polypropylene Yarn Shrinkage in the Heat-Setting Process Using the Fuzzy Inference System

In the carpet industry, yarn shrinkage is a very important specification, the percent of shrinkage affected by heat setting parameters, time and temperature. In order to obtain the best uniform appearance of carpets, the shrinkage of pile yarns should be minimum in the carpet sizing process. An inappropriate heat set yarn may cause an undesirable shrinkage result and uneven pile height on carpets after the sizing process. It could be useful for manufacturers to understand the optimum condition of heat setting to obtain the low shrinkage of heat set yarns before weaving. Therefore, a fuzzy logic model is designed to predict the shrinkage percentage of polypropylene yarn in different heat setting conditions. Time and temperature are taken into account as input variables and yarn shrinkage is predicted as output. For validation of the model, the yarn samples heat set under various sets of time and temperature and finally yarn shrinkages have been measured experimentally. The result of the fuzzy model prediction compared to regression results and signify the fuzzy results present good and better match with experimental results with the acceptable R2=0.97 and average error (2.59%).

Preparation and properties of melt‐spun poly(fluorinated ethylene‐propylene)/graphene composite fibers

AbstractThe matrix of poly(fluorinated ethylene‐propylene) (FEP) was modified with graphene (GE) as filler, and then the composite fibers were prepared by melt spinning method with a twin‐screw extruder. The effects of both the draw ratio and GE content on the structures and properties of FEP/GE composite fibers were investigated. The results showed that the addition of nanoparticles reduced the crystallization of molecular chains and the orientation of crystalline units in the fibers, while the drafting and heat setting process could effectively improve the crystallinity and orientation of composite fibers. Moreover, the addition of GE improved the mechanical properties of the composite fibers and had no effect on the chemical resistance of the composite fibers. A significant enhancement of mechanical properties of the composite fibers was obtained at low GE content, that, a 35.5% improvement of tensile strength and a 19.5% increase of Young's modulus were achieved at a GE content of only 0.3 wt%. Compared with pure FEP fibers, the oil affinity of composite fibers was also significantly improved. The prepared FEP/GE composite fibers that showed excellent chemical resistance have potential application in oil‐water separation, especially in high temperature resistant fibrous materials.

Development of auxetic warp knitted fabrics based on reentrant geometry

This paper reports a novel method to fabricate auxetic warp knitted fabrics on a tricot warp knitting machine based on a special structure design and knitting process. Three auxetic warp knitted structures were successfully developed and all of them were designed to form a reentrant hexagonal geometry to acquire an auxetic effect. To provide the fabrics with reentrant frames, elastomeric yarns and stiff yarns were used to form the elastic underlaps and stiff underlaps, respectively. While the elastic underlaps can keep the reentrant structures stable, the stiff underlaps can support the reentrant structures to keep their reentrant frames. To alleviate the transfer of yarns in the loops under tension, an additional front yarn guide bar was used to feed binding yarns to basic reentrant structures. After knitting, all the fabrics were subjected to a heat setting process to keep their shape and a tensile test to assess their auxetic behavior. The experimental results showed that all the fabrics exhibited an obvious auxetic behavior within a wide range of strain. In particular, the fabrics retained auxetic behavior until breaking when stretched in the wale direction, and the Poisson’s ratio of the fabrics could be as low as –0.5. On the other hand, the fabrics exhibited a large tensile elongation when stretched in the course direction and their Poisson’s ratios changed from negative to positive after the tensile strain exceeded a certain value.

Analysis on Property Discrepancy between Core and Sheath Fibers in Braided Harness Cords

Harness cord is widely used in the industries of trademark, carpet, home textile and towel, which is the most important lifting part in the jacquard loom. In this article, the tensile properties and crystallization performance of core and sheath fibers in harness cords were measured separately. The influence of heat setting during the finishing process on the fibers’ properties was studied. The results showed that the tensile strength, elongation at break and specific work of core fibers were higher than that of sheath fibers. This was because the crystallinity and preferred orientation of fibers were changed by the heat and applied tension during the heat setting process. The core fibers showed better crystallinity, preferred orientation and crystallite size than that of sheath fibers. Besides, the tensile properties and crystallization performance of fibers before and after heat setting was compared. It revealed that the heat setting enhanced the tensile properties and crystallization performance of core fibers, while the opposite phenomenon was observed in sheath fibers.

Optimation of AMC’s Tensile Properties Using Adaptive Neuro-Fuzzy Inference System (ANFIS)

The addition of organoclay to Aluminium Matrix Composite (AMC) with heat treatment and setting process variables was able to change the microstructure affecting its mechanical properties. The method used in this study was a hot press. The pressure used was of 137.8951458634 MPa, and the temperature varies from 490-600 °C with a holding time of 3 hours. Characterization was carried out using XRD, optical microscope, hardness tester, and ultrasonic tester. The data analysis showed that the hardness increased from 126 to 197 HVN. Furthermore, the mass density also increased, and reached an optimal value with the addition of 1% wt of organoclay at a temperature of 550 °C. The microstructure exhibited that AMC was formed and increased the hardness and density. XRD results indicated that aluminium phase was successfully detected. From the results of several characterizations, it can be concluded that the optimal material has the composition by adding 1% wt of organoclay with a heating temperature of 550 °C, a pressure of 13.7859558534 MPa and a long press time of 3 hours. In this study, we construct a relationship between process variables based on experimental, computational design and use the Inference Adaptive Neuro-Fuzzy inference (ANFIS) method. Furthermore, the prediction accuracy made by the model was investigated based on the test case. The results showed that the hot press method had a relationship with the attraction properties having the same conclusion using experiments and ANFIS.

Heat and moisture transfer performance of thin cotton fabric under impingement drying

To investigate the drying characteristics of thin cotton fabric for reducing the energy consumption during the heat setting process, a two-dimensional heat and moisture transfer model considering lateral heat and moisture transmission under the impingement drying condition was developed in this study. The curves of the variation in fabric temperature and moisture content over time were obtained and the results indicate that the drying rate increases with the decrease in the moisture content in the fabric. In addition, non-uniform distributions of temperature and moisture on the fabric over time were obtained. The drying time per unit area on the fabric was found to increase with time. Further, experiments were conducted to test the heat and moisture transfer performance of the fabric, and the experimental results agree reasonably well with the calculations.

Heat and moisture transfer performance of thin cotton fabric under impingement drying

To investigate the drying characteristics of thin cotton fabric for reducing the energy consumption during the heat setting process, a two-dimensional heat and moisture transfer model considering l...