Thickness is one of the most important indicators characterizing yarn. The thickness of the yarn is assessed using various indicators: the cross-sectional diameter of the fiber, the area of this cross-section, the tex system and number. (True, it is not the thickness itself that is determined by the number, but the fineness of the yarn.)
Yarn number
The label of a factory-produced skein often indicates the yarn number, expressed as a fraction, for example, No. 32/2. The numbers before the line indicate the metric number of the yarn: the larger the number, the thinner the thread.
The metric number expresses the length of one gram of yarn in meters (m/g or, equivalently, km/kg). The number after the line shows how many threads the yarn is twisted from.
Example. The ideal yarn for machine knitting (fine) is 32/2 in 1 kg and has a length of 16 km because it consists of two threads.
In a skein of 100 g - 1600 m
in 2 additions - 1600:2 = 800 m /100 g;
in 3 additions - 1600:3 = 533 m /100 g;
in 4 additions - 1600:4 = 400 m /100 g;
in 5 additions - 1600:5 = 320 m /100 g;
in 6 additions - 1600:6 = 267 m / 100 g, etc.
Tex
According to the international system of tex, instead of fineness, the thickness of the fibers should be measured in tex (unit of linear density).
Tex is the amount of mass per unit length.
1 tex is the mass of one kilometer of thread in grams.
Number and text are reciprocal quantities.
The word tex comes from Lat. weave.
Wraps per inch
You can determine the yarn number by taking a ruler and winding the thread tightly (or on a pencil and applying it to the ruler), counting how many threads or turns fit in one centimeter or inch. This method is not applicable for fine yarns such as mohair (which is why the boxes in the table below are not filled in for fine and very fine yarns).
WPI= wraps per inch - number of wraps in one inch (2.54 cm).
Number of threads (Ply)
Ply is the number of threads that make up the yarn. 2-ply yarn, for example, is twisted from two threads (twisting allows you to “balance” the thread). Yarn sold in stores is most often twisted from more than 2 threads.
It is clear that there is no direct relationship between the thickness of the yarn, the knitting density and the number of threads from which the yarn is spun. For example, both thin yarn (floss) and thick yarn (wool) can be spun from 6 threads. However, according to old standards, 4-ply is synonymous with fine yarn (criticism)
Goal of the work: Study of methods for determining linear density, curl and twist indicators of threads and sewing threads.
Devices and materials: thickness gauge , samples of sewing threads, ruler, textile magnifying glass, electronic scales, twist gauge, preparation needles.
Tasks: 1. Study the classification of textile threads used in the production of clothing materials.
2. Study the characteristics of the structure of threads and sewing threads.
3. Determine the indicators of the structural characteristics of 3 types of threads.
4. Prepare samples and conduct tests to determine linear density, direction of twist, number of folds, calculated and actual diameter of threads and sewing threads.
Basic information
Types of textile threads. In modern textile production, a wide range of threads of various structures is used: classical types of yarn, complex, combined threads and monofilaments, film threads and thread-like knitted, woven, braided textile products (chains, cords, ribbons, braids, etc.). Knowing their structural features, it is relatively easy to predict the properties of materials made from these threads and products.
Distinctive feature yarn is the presence of protruding fiber tips on its surface. When untwisted, the yarn eventually breaks down into individual fibers of limited length. Combed, carded, rotor-spun and machine-spun yarns differ in the degree of surface fluffiness: as a rule, combed yarn has a smoother and less fleecy surface, while machine and high-volume yarns have the greatest fluffiness and volume.
Unlike yarn surface complex threads, consisting of elementary filaments, smooth, even, and without protruding tips, unless the filaments are damaged. Surface voluminous and fluffy textured threads, the elementary threads of which have a stable crimp, are covered with individual loops-sucrutins. Their number and size depend on the texturing method. Shaped threads have periodically recurring local changes in their structure. Local structural effects found in fancy yarns are very numerous and varied (loops, knots, thickenings, twists, roving areas, lumps of fibers, etc.).
When untwisted, twisted threads are separated into component threads: yarn - into single yarns, complex threads - into single threads, combined threads - into threads of various types. The components of the thread in the structure of twisted threads are located along helical lines and therefore their turns are noticeable on the surface. The density of the arrangement and the inclination of the turns relative to the longitudinal axis increase as the degree of twist increases from minimum values in flat twist threads to maximum values in crepe twist threads. Crepes have significant rigidity, elasticity and unbalanced twist. This causes them to wriggle and twist when free, forming twists.
Structural characteristics of textile threads. The structure of single-strand yarn is characterized by the thickness, length, shape of the fibers, as well as their number and uniformity of distribution in individual sections, relative position and intensity of twist. The main structural characteristics of twisted yarn are the thickness, amount and direction of twist of the single-strand yarn; number of additions, i.e. the number of threads forming the twisted yarn, the intensity and direction of twist in the twisted yarn.
Thus, the structural characteristics of textile threads and sewing threads are thickness (linear density of threads), number of folds, direction and amount of twist, twist.
The use of linear cross-sectional dimensions to characterize the thickness of threads is inconvenient for a number of reasons: its measurement is hampered by the irregular shape of the cross-section of the threads, the presence of voids and air spaces between the fibers in the yarn, the dependence of the thickness on the degree of twist and packing density of the fibers in the cross-section of the threads, the possibility of flattening of the threads during use to determine the thickness of devices.
In this regard, the thickness of threads and sewing threads is assessed by indirect units of measurement: linear density, trade (conventional) number.
Linear density T, tex, an indirect unit of measurement of the thickness of fibers or threads, is directly proportional to their cross-sectional area, i.e. The higher the tex number, the thicker the thread. Defined as the ratio of the thread mass T, g, to its length L, m
T=1000 m/L(2.1)
Units of measurement of linear density, in addition to tex according to GOST 10878-70, are millitex (mtex) 1 mtex = 10 -3 tex; decitex (dtex) 1 dtex = 10 -1 tex; kilotex (ktex) = 10 3 tex.
The linear density of twisted and caned threads is called resulting linear densityT R.
Linear density is distinguished between nominal, actual, calculated and standard.
Standard linear densityT k– this is the actual linear density of a single or twisted (caned) thread, reduced to normalized moisture content. These indicators are calculated using the formula
, (2.2)
Where Wн– normalized moisture content of threads, %;
Wф – actual thread moisture, %.
In terms of linear density, you can only compare the thickness of threads of the same fibrous composition and structure.
Nominal (That) call the linear density of a single thread planned for production in production; it is usually indicated in the technical characteristics of the thread and material (GOST 10878-71, GOST 11970.0-5-70, GOST 21750-76).
Estimated linear density (T r) are calculated for reed threads in which its individual components are not subject to joint twisting
T r =T 1 +T 2 +…+T n, (2.3)
Where T 1 ,T 2,T n– nominal linear density of individual stitched threads.
Actual linear density textile thread ( T f) determined experimentally in the laboratory and calculated using formula (2.4)
T f =1000× S m/L×p,(2.4)
Where Sm– total mass of elemental samples, g;
L– length of thread in an elementary sample, m;
P– number of elementary samples.
To characterize the thickness of sewing threads, the symbol is used - trade number N, which is indicated on the labeling of each product unit. The higher the numerical value of the trade number, the thinner the sewing thread.
The trade number shows the number of meters of yarn weighing 1 g
N=l/m , (2.5)
Where l– thread length, m;
m– mass of thread, g.
The thickness of twisted threads (yarn) is indicated by a fraction, the numerator of which is equal to the number of threads that make up the twisted yarn, and the denominator is the number of threads included in it. The relationship between the linear density of sewing threads and their trade number is expressed by the expression:
T= 1000/N(2.6)
An important indicator when choosing sewing threads for sewing products is the diameter of the threads. It is determined by calculation and experiment.
Estimated thread diameter, mm, determined by the formula
, (2.7)
where d is the average density of the thread, mg/mm 3 values of which are given below.
Experimentally, the diameter of the threads is measured using projection devices or microscopes
The direction of twist characterizes the location of the turns of the peripheral layer of the thread: when right twist(Z) the components of the thread are directed from left to top to right, with left twist(S) – from right up to left.
Figure 2.1 – Arrangement of turns in the yarn:
a – right twist; b – left twist
In silk threads, on the contrary, the right twist is designated S, and the left twist is Z. The direction of twist of sewing threads affects the process of loop formation and the loss of thread strength during sewing.
The structure of twisted threads is characterized number of additions– the number of its constituent threads.
Thread twist characterized number of torsions K, which indicates the number of turns around the axis of the thread, calculated per unit length of the thread (1 m) before unwinding, and is determined on a twist meter. The actual number of twists characterizes the degree of twisting of threads of the same linear density. In standard testing, two methods are used to determine the actual number of twists (actual twist): And double torsion(GOST 6611.3-73). With the first method direct unwinding The thread is untwisted on the twist gauge until the component threads are completely parallel. The number of twists is noted on the counter. The readings are recalculated per 1 m of thread length - this is the actual twist.
Figure 2.2 shows universal twist gauge KU-500. The device consists of a housing 12, a tension device and an eyepiece, mounted on a guide 22 with brackets 4 and 18, respectively. The housing 12 is a box inside which is mounted an electric motor, a clutch with a set of gears for rotating the right clamp 10 and a mechanism for changing the direction of rotation of the counting device 11. The tensioning device consists of a bracket 4 with an elongation scale 5 attached to it and a swinging system with a pointer 6, a left clamp 7, a load scale 2 with a weight 3 and a counterweight 20. To fix the pointer 6 in the zero position, a clamp 21 is provided. The eyepiece consists of 8 magnifiers and 9 screen with black and white background.
Figure 2.2 – Universal torque meter
Before threading the thread into the clamps of the twist gauge, the method for determining the number of twists, the direction of twist of the thread and test parameters are established: the number of spot samples, clamping distance, preload.
After determining the test parameters (distance between clamps, pre-tension values), the required distance between clamps 7 and 10 is established. Then, by moving the weight 3 along the load scale 2, the corresponding pre-tension force is created. If the required tension force should be more than 50 cN, an additional replaceable weight is installed on weight 3, and a counterweight 19 is screwed into the right end of the load scale. Clutch switch 13 is set to position Z or S, corresponding to the direction of twist of the thread being tested. The package with the test thread is put on the rod 17, the end of the thread is pulled through the eyes of thread guides 1 and 23 and secured first in the left swinging clamp 7, and then in the right clamp 10 so that the arrow pointer 6 points to the zero division of the elongation scale 5. When determining the number torsion using the direct unwinding method, arrow 6 is secured in the zero position with lock 21. Toggle switch 15 is placed in position Z or S similar to switch 13. The rotation speed of the right clamp 10 is controlled by variable resistance using handle 16. Rotating, the right clamp unwinds the thread. The parallelism of the component threads is checked with a preparation needle, passing it between the threads from the left clamp to the right. If the components of the thread are close to parallelism, the unwinding is completed by rotating the handle 14. Then the readings of the counter 11 are recorded and the number of twists per 1 m is calculated.
When determining the number of thread twists double torsion method The arrow limiter 6 is installed in such a way that the arrow can deviate to the left from the zero scale mark by no more than two divisions. Turn on the device. The right clamp, rotating in the direction opposite to the direction of twist, will first unwind the thread and then twist it. When unwinding, the thread lengthens and the arrow 6 deflects to the left to the limiter, and when twisting, the thread shortens and the arrow moves to the zero mark of the scale. When the arrow pointer 6 returns to the zero position, the electric motor is turned off. The counter reading is equal to twice the number of twists at a given clamping length. The number of torsions per 1 m is calculated using formula (2.8), taking into account that the number of torsions recorded by the counter should be divided in half before substitution into the formula.
The number of torsions is calculated using the formula
, (2.8)
Where n– number of tests;
L 0– clamping length, m;
Ki – number of torsions in individual trials.
twist coefficient, characterizing the intensity of twisting of threads of different linear densities, calculated by the formula
(2.9)
Since, when twisted, the constituent threads are arranged in spiral turns, their length shortens, or twist.
The amount of twist,%, determined by the formula
(2.10)
Where L 1 – length of untwisted thread, mm;
L o – length of twisted thread, mm.
In addition to the characteristics discussed above, the structure of the yarn is assessed hairiness or fluffiness - the presence of fiber tips on the surface. The following characteristics are most often used to assess hairiness: the number of fibers per unit length (usually per 1 m) and the average length of fibers in millimeters.
Method of doing the work
Analysis of the structure of textile threads. The study of the structure of various textile threads is carried out on samples obtained from packages or taken out of textile materials, and consists of unwinding and examining the samples under a magnifying glass and under a microscope at low magnification. Samples of threads taken from materials have additional crimp, so before examination under a magnifying glass or microscope, it is advisable to fix them (glue the ends) in a straightened state on a paper backing or place them between two glass slides. The prepared sample is placed on a microscope stage and examined in reflected light.
When studying samples, the main distinctive features of the structure of the thread are revealed: the appearance of its surface, the number of folds, the type and shape of the constituent fibers and threads, the nature of their location in the structure, the direction of twist, etc. To determine the direction of twist, the thread is slightly untwisted by hand in a small area. If the upper end of the thread unwinds clockwise, the thread has a right-hand twist (Z), if counterclockwise, the thread has a left-hand twist (S).
Determination of linear thread density. The linear density of textile threads is determined according to GOST 6611.1-73 “Textile threads. Method for determining thickness." The test is carried out by weighing elemental samples in the form of skeins.
The type of elementary samples (skein or piece), their length and quality are established for each type of thread in the relevant regulatory and technical documentation GOST 6611.0-73. When performing work, unwind 10 m of threads (5 samples). After this, the mass of the skeins is determined and the linear density is calculated using formula (2.1) and the trade number using formula (2.5). Electronic scales are used to weigh thread segments.
Design and principle of operation of electronic laboratory scalesCAS MW-150T.
Scales (Figure 2.3) are designed for weighing small samples of fibers, threads, materials weighing no more than 150g. with an accuracy of 0.005g. Accuracy class (GOST 241044) – 4. Type of measurements – strain gauge. The device is equipped with automatic zero setting and gain adjustment. Laboratory scales with liquid crystal display (1), number of indicator digits -6. Working platform with a diameter of 125mm (2) made of stainless steel.
To work on electronic scales you need:
Align the device to the level (3), which is located to the left of the electronic display;
Place a plastic transparent cap on the surface of the device;
Connect the power supply of the scales to the electrical network;
Turn on the device with the “ON/OFF” button (4).
Wait until the automatic testing of the device is completed (until the electronic display reads “0.000”);
Open the hood cover;
Place the material to be weighed with tweezers on the center of the scale pan;
Close the hood cover and wait for the specific weight of the material to be established.
The scales should not be located near heating devices, nor should they be exposed to air currents.
Figure 2.3 – General view of electronic laboratory scales CAS MW-150T
Determining the diameter of threads and sewing threads. By calculation, its diameter is determined by formula (2.7). Experimentally, the diameter of sewing threads is determined by measuring them under a microscope or thickness gauge. To determine the diameter of the threads under a microscope, they are usually wound onto a glass slide in spiral turns in one layer. To maintain constant tension, one end of the thread is glued to a glass slide, and a weight is suspended from the other. Rotate the glass slide evenly and wrap a thread around it.
To measure the thickness of materials, as a rule, thickness gauges of the TR (manual thickness gauge) and TN (desktop thickness gauge) types are used (Figure 2.4), which can differ in the measurement range, the reach of the body arc, as well as the presence or absence of a mechanism for normalized force measurement. The principle of operation of the thickness gauge is reduced to measuring the vertical distance between the supporting platform on which the material sample is located and a parallel measuring platform through which pressure is transmitted to the sample.
Design and principle of operation of the thickness gauge. The standard requirements (GOST 12023–93) are met by an indicator-type thickness gauge TN 40-160 with a standardized measuring force. The division value is 0.1 mm. Measuring range 0-40mm.
Before working with the device, check the zero setting. If, when the measuring surfaces come into contact, the arrow of the reading device does not align with the zero line of the scale, then by turning the rim, align the zero line with the arrow (while loosening the pressure of the screw on the body).
Figure 2.4 – General view of the desktop thickness gauge
1 – lever, 2 – indicator, 3 – small scale, 4 – upper table, 5 – lower table, 6 – rim, 7 – measuring rod.
It is also necessary to check the consistency of the readings. To do this, raise the measuring rod 2-4mm and lower it two or three times. If, with the measuring surfaces closed, the arrow takes any other position, then by turning the rim, align the zero line of the scale with it.
A spot sample is placed between the lower fixed and upper movable tables. The movement of the upper table is transmitted to an indicator having two scales.
To measure the diameter of sewing threads, a special comb device is required for the thickness gauge. The threads are threaded between the teeth of the combs and the disks of the device. After lowering the upper disk onto the threads, the needle on the thickness gauge scale shows the value of the thread diameter. The most accurate result is obtained after simultaneously threading six or more threads. At the same time, the threads are less flattened under the pressure of the disks. Conduct 10 such tests, then derive the average value, compare the actual and calculated values of the thread diameter, and draw conclusions.
Determination of the direction of twist, number of folds. To determine the direction of twist, a short piece of thread is pinched with your fingers and, held vertically, slightly untwisted. If the upper end of the thread unwinds in a clockwise motion located in a horizontal plane, it has a Z twist (silk - S twist); when the upper end is untwisted counterclockwise, the thread has an S twist (silk has a Z twist).
The number of folds is determined by securing both ends of the sewing threads, and unwinding it until the strands are completely parallel, which is checked with a needle. After this, one of the strands is also untwisted and the needle is divided into threads, the number of which is recorded. The total number of folds is equal to the sum of the threads included in the strands.
Determination of the equilibrium of twisted threads. When the thread is twisted, due to reversible elastic and elastic deformation, a torque arises, usually directed in the direction opposite to twisting. This leads to unwinding of the thread and the formation of loops - sukrutin. Such a thread is called nonequilibrium. Non-equilibrium is especially important for sewing threads and twisted yarns. Twists of unbalanced threads get stuck in the holes of sewing machine needles and thread guides and cause thread breakage. In addition, if the thread is unbalanced in twist, then when sewing, the resulting loop may deviate so much from its normal position that it will be outside the range of action of the shuttle nose, as a result of which the shuttle may pass without catching the loop. The imbalance of threads is most often determined as follows. A thread 1 m long is folded in half (Figure 2.5). The thread is considered to be in equilibrium if no more than six turns are formed on its hanging part.
Figure 2.5 – Determining the balance of threads during twisting
a – balanced thread, b – unbalanced thread
The test and calculation results are recorded in Table 2.1.
Table 2.1 - Linear density and indicators of thread structure
Control questions:
- Define the concepts of linear density: actual, resulting, nominal, conditional, normalized, calculated?
- How to determine the actual linear thread density, and why is this necessary?
- How to determine the actual diameter of sewing threads, and why is this necessary?
- Method for determining twist, twist, balance and number of folds of threads?
- What is twist, twist coefficient, twist?
- Which sewing thread is called non-equilibrium thread? The influence of disequilibrium of sewing threads on production processes.
- How to determine the direction of twisting of sewing threads, and why is this necessary?
- List the types of textile threads.
Laboratory work No. 3
Weave Analysis
Goal of the work: Familiarize yourself with the methods of weaving analysis. Acquire skills in sketching weaving patterns.
Devices and materials: tissue samples, textile magnifying glass, dissecting needle, colored paper.
Tasks: 1. Study the classification of weaving, the principles of their mathematical designation and methods of weave analysis.
2. Analyze the weaves of various types of fabric.
3. Create a weave layout
Basic information
Textile is a textile fabric formed as a result of the mutual interweaving of 2 or more mutually perpendicular systems of threads. The threads located along the fabrics are called warp; the threads lying across the fabrics are weft. Various sequences of alternating warp and weft overlaps create a huge number of weavings, which are one of the main structural characteristics of fabrics. Weave determines the order of mutual arrangement and connection of the warp and weft threads.
The place where the warp and weft threads meet is called overlap. They are distinguished: main overlap, when on the front side of the fabric the warp thread is located on top of the weft thread, and weft overlap, when the weft thread is located above the warp thread. Shift (z) shows how many threads have shifted vertically in the weave between the overlaps of one thread relative to the overlaps of the other.
Finished weave pattern , called rapport. It determines the smallest number of warp threads (R 0) and weft threads (R y) forming it. The area where the thread passes from the front side to the wrong side and vice versa is called communication field. The area where the weft and warp threads, touching, intersect, is called contact field. Areas where the threads do not touch - free field. The through pores formed between the threads are called lumen fields. Communication, contact and free fields can be basic and detailed.
The weave pattern is presented in the form of a graph (Figure 3.1). On the graph, each horizontal row corresponds to a weft thread, each vertical column corresponds to a warp thread; The warp and weft threads are conventionally assumed to be the same thickness, with no gaps between them. The main overlaps on the graph are shaded, the weft overlaps are left unshaded.
Figure 3.1 – Scheme (a) and graph (b) of weaving
Repeat can be expressed as a fraction, the numerator of which shows the number of main overlaps, and the denominator the number of weft overlaps in the repeat.
Fabric weaves are divided into 4 classes (Figure 3.2):
1. Simple (main) weaves
2. Finely patterned weaves
3. Complex weaves
4. Large-patterned (jacquard) weaves.
Figure 3.2 – Classification of weaving
Simple weaves fabrics have the following features: warp repeat is always equal to weft repeat; Each warp thread is intertwined with each weft thread only once. Simple weaves include plain, twill and satin weaves.
Plain weave has the smallest rapport: Ro=Rу=2. Plain weave fabrics are double-sided, with a uniform smooth surface on the front and back sides (Figure 3.3). Since the threads form only bonding and contact fields, the structure of plain weave fabric has the greatest unity and, other things being equal, greater strength and rigidity. This weave is the thinnest, lightest and least dense fabric.
Twill weave has rapport R ≥ 3, S=1. It is indicated by a fraction: its numerator shows the number of main overlaps within the repeat, and the denominator shows the number of weft overlaps.
Twills are distinguished: weft 1/2,1/3, 1/4, on the front side of which weft overlaps predominate, and basic 1/2,1/3, 1/4, on the front side of which the main overlaps predominate. A characteristic feature of twill weave fabrics is the presence on the surface of noticeably pronounced diagonal stripes formed by longer overlaps (Figure 3.4).
Figure 3.3 – Scheme and graph of plain weave
Figure 3.4 – Scheme and graph of twill weave
Most often the direction of the diagonal is positive - to the right, less often negative - to the left. The angle of inclination of the diagonal hems depends on the ratio of the thickness of the warp and weft threads and the density of their arrangement. Fabrics of this weave are distinguished by greater softness, elasticity, stretchability, and drape. Semi-silk fabrics are produced using the basic twill weave. Wool blend fabrics, cotton warp and wool weft are produced using weft twill weave.
Satin (satin) the weave is characterized by repeat R≥5 and shift z ≥ 2. The front side of the satin weave is formed by long main overlaps, and the satin weave is formed by weft overlaps. Fabrics formed by these weaves have a smooth, even surface with increased shine. Silk fabrics (atlases) are most often produced using satin weave (Figure 3.5), and cotton sateens are produced using satin weave (Figure 3.6).
Figure 3.6 – Scheme and graph of satin weave
Finely patterned weaves are divided into two subclasses: derivatives of main weaves and combined ones.
Derivatives weaves are formed by modifying the main ones. These include derivatives of plain weave, such as matting, rep (Figure 3.7), twill - for example, reinforced twill (Figure 3.8), complex twill (Figure 3.9), reverse twill (Figure 3.10), as well as derivatives of satin (satin) - reinforced satin, reinforced satin.
Figure 3.7 – Scheme and graph of rep weave
Figure 3.8 – Scheme and graph of reinforced twill weave
Figure 3.9 – Scheme and graph of complex twill weave
Derivative weaves are obtained by strengthening single warp or weft overlaps. Matting weave fabrics are produced by increasing the warp and weft overlaps at the same time. In fabrics of this weave, the checkerboard pattern is more noticeable (Figure 3.11) .
Figure 3.10 – Scheme and graph of reverse twill weave
Matting weave fabrics are produced by increasing the warp and weft overlaps at the same time. In fabrics of this weave, the checkerboard pattern is more noticeable. .
Figure 3.11 – Scheme and graph of matting weave
TO combined weaves include crepe (Figure 3.12), relief, etc. They are formed by combining various weaves.
Complex weaves include double, multi-layer, pile. At least three systems of threads are involved in their formation.
Figure 3.12 – Scheme and graph of crepe weave
IN double weaves, front and back sides, are most often formed from threads of different quality or color and can have different weaves. Since the threads of the upper and lower weaves are located one above the other, double weave fabrics have a significant thickness.
Double weaves can be double-faced or double-layered. D vuhfacial(one-and-a-half-layer) are formed from one warp and two wefts or two warps and one weft.
Figure 3.13 – Scheme of cutting a two-layer weave fabric with different methods of connecting the fabrics
Double layer weaves are formed by two systems of warp threads and two systems of weft. The connection of the fabrics is carried out over the entire area of the fabric using the lower base, using the upper base or using a special clamping base (Figure 3.13).
Figure 3.14 – Cutting diagram of weft weave fabric
Pile weaves can be weft pile (Figure 3.14) and warp pile (Figure 3.15). The surface of pile weave fabrics is covered with trimmed or terry pile. In openwork weave fabrics, the warp threads lie in zigzags, moving from one row to another and creating a transparent pattern reminiscent of hemstitching.
Figure 3.15 – Cutting diagram of warp weave fabric
Large patterned (jacquard) the weaves have a large repeat (more than 24). Such weaves are produced on special jacquard machines.
Method of doing the work
Determining the type of weave. When starting to analyze the weave, first determine the direction of the warp and weft, the front and back sides of the fabric, after which they begin to sketch the weave.
Determination of warp and weft threads. The warp threads are always located along the edge. If there is no selvage in the sample, the fabric should be pulled in both directions - usually the fabric will stretch more along the weft. If several threads of both directions are removed from the analyzed sample with a dissecting needle, the weft threads will be curved more than the warp threads (the exception is rep-type fabrics that have a thin warp and a thick weft). The warp threads are usually more twisted than the weft threads; they are smoother and stiffer, the weft threads are looser and softer. More often, warp threads have a twist direction of Z, and weft threads have a twist direction of S. If there are twisted threads in one direction of the fabric and single ones in the other, then the warp threads will be twisted. The main threads are located more evenly, parallel to each other, sometimes cuts of two or three threads from the teeth of the reed are preserved in the fabric. The density of the fabric along the weft is less uniform: there may be threads arranged in an arc or superimposed on one another, and distortions of the fabric along the weft are not uncommon.
Determining the front and back sides of the fabric. To recognize the front and back sides, the fabric should be placed so that both sides can be compared at the same time. In this case, the warp and weft threads in the compared sides should be located in the same direction. In some fabrics, the difference between the front and back sides is more pronounced, in others it is barely distinguishable. The weave pattern appears more prominently on the front surface. The finishing of the front side is more thorough; the ends of the fibers are less visible on it. In pile fabrics, the cut pile is always located on the front side. In brushed fabrics, the pile on the front side is thicker, better rolled, and cut shorter than on the back side. In printed fabrics, the design is on the front side.
In this review article we will try to tell you how to determine the length of the thread in a skein of yarn, the label of which was lost or did not exist at all. A few words will also be said about what difficulties may arise when knitting a product according to the finished description using a different yarn.
It happens that you have yarn lying around at home, but the label for it has long been lost, and it is not possible to find out how many meters there are in a skein. In this case, there is a universal method that can help you resolve this issue. Of course, you can use the most primitive method, using a meter to measure the length of the thread in a skein by unwinding it. However, I want to offer a simpler method.
Take a regular student's ruler and wrap the yarn around it, placing the skeins close to each other without overlapping. Now count how many skeins fit into 2.5 cm, and then use the table below and determine the thickness of the yarn from it.
I use this method when I buy yarn at the market. The skeins are sold there without labels or even in skeins (that is, the yarn will then need to be wound into balls). By the way, there is one effective way that can help determine the preferred number of knitting needles. To do this, take the yarn you are going to knit from and fold the thread in half, twisting it a little. Now measure the width using a ruler. Let's say you get 2.5 mm, this means that you need to take knitting needles 2.5 mm thick.
Now let's talk a little about what to do if you liked a model from a magazine, but it is impossible to find the same yarn listed there. First of all, it is necessary to take into account that when replacing yarn, that is, selecting an analogue, you need to pay attention to the composition of the yarn and the ratio of length and weight.
Even though if you choose the perfect replacement, the knitting density indicated in the model may not match yours. This may be due to the fact that the twist of the original yarn and the analogue yarn is different. For example, an analogue yarn consists of two threads, while the original consists of three. In this regard, the cross-section of these two threads is different; the original will have an almost circular cross-section, but the yarn made from two threads will have an oval cross-section. The same situation may occur when you fold several thin threads into one to obtain the required knitting density. Due to the fact that the folded threads are not twisted, the cross-section also turns out to be oval rather than round.
But despite all the obstacles, if you manage to select a yarn that is as close as possible in knitting density, the intended product will turn out, and it will practically not differ from the one shown in the original.
knitweek.ru
How to calculate the “meterage” of a thread folded from two threads of different thicknesses.: ru_knitting
You have two threads: one 350m/100g, the other 500m/100g. You put them together to knit and for some reason (for example, to calculate the future yarn consumption) you want to know how many meters per 100g. will be in a new thread.UPD. The number of meters of yarn per unit of weight (usually 100 grams) is usually called “meterage”. This characteristic is indicated on the yarn labels.Using the law of conservation of mass and simple manipulations with fractions, I got the following formula: P1 - “meterage” of the first thread P2 - “meterage” of the second thread P - “meterage” of the thread folded from the first two P = (P1xP2) / (P1 + P2) In our example, approximately 206 m/100 g. Solution: From our definition it follows that “meterage” = length/weight. Let’s take two pieces of our threads, each 1 meter long. Their total mass will be equal to the sum of the masses of the component threads. We can calculate the masses of these segments, since we know the length and “footage” of each. Mass = length/"footage". We get the formula: 1/P=1/P1 + 1/P2 We bring it to a common denominator, simplify and get the formula P= (P1xP2)/(P1+P2). Divide the product of our values by their sum. UPD From the comments adding: olga_vadimova wrote:
I repeat the thought once again - the final universal formula makes it possible to calculate the yardage of a new thread made up of the nth number of different threads with the yardage indicated for different weights of the balls. And you simply proposed a special case of this hypothetical universal formula. ni_spb wrote:...how you can calculate the “meterage” for the nth number of threads: 1/P= 1/P1+1/P2+1/P3+... - if you add three or more threads, then nothing changes except the number of terms in the formula. The total mass is equal to the mass of the components. P from here is not difficult to calculate in each case. Regarding different threads with “meterage” indicated for different weights of balls: Suppose you have one value of 300 m / 50 grams and another 588 m / 112 grams. Divide 300 by 50. And also 588 by 112. Work with these numbers (you will have these values P1 and P2). The result obtained from the formula (in this case 2.8) can be reduced to a convenient form. If you multiply it by 100, you get the footage of the new thread of 100 grams. Multiply by 25 - accordingly, 25 grams.
ru-knitting.livejournal.com
Lesson 1. Selection of threads and knitting needles
Let's talk to you today about choosing knitting needles and yarn for knitting. The quality of a knitted product very much depends on the correct combination of knitting needle thickness and thread thickness.
As a rule, using knitting needles of small diameter (No. 1-3), this is how openwork patterns and elegant things are knitted from thin threads. Accordingly, thicker yarn requires thicker knitting needles. How to determine what size knitting needles we need?
If you have yarn with a label, you need to look at the label. On it, the manufacturer usually indicates the size of the knitting needles recommended for this yarn. An example in the photo - knitting with these threads requires knitting needles ranging from 2.5 to 4 mm.
How to determine the size of the knitting needles? As a rule, the number is indicated on the knitting needles. This number is equal to the diameter of the spoke in mm. If there is no number on your knitting needles, it doesn’t matter. It is very easy to define. Take a thin sheet of paper and pierce it with a knitting needle. Then use a ruler to measure the resulting hole, this value will be the size or number of the knitting needle.
But what to do if the recommended needle number is not indicated on the yarn or if you have threads without a label at all? Then we use the rule: the diameter of the knitting needles should be approximately twice the diameter of the thread. It is better to measure two threads at once, so the value will be more accurate. An example of measuring threads and selecting knitting needles for them is in the photo below. As you can see, the diameter of the two threads is 4 mm, which means needles are needed No. 4, which coincides with the recommendations indicated on the label
For your first experiments, I would advise you to take knitting needles No. 4-5 and yarn whose thread length in a skein is approximately 300 m per 100 g (this is also indicated on the label). It is better to take acrylic or wool blend yarn, twisted into one thread.
A few more words about knitting needles. On sale we can find a large number of different types of knitting needles. Which ones are better to choose? There are long straight knitting needles, two pieces in a set, these are used for simple straight knitting. Also, the knitting needles can be short, in a set of 5 pieces, these are used for circular knitting, for example socks. For circular knitting of large items, ring knitting needles are used; these are 2 knitting needles connected by fishing line.
Knitting needles can be made from various materials. It can be wood, bone, plastic or metal: aluminum or steel coated with chrome or nickel. So every craftswoman will be able to choose the knitting needles with which she will be comfortable working. To begin with, I would advise choosing straight, long metal knitting needles. It will be easier to knit with them, because the thread slides over them more easily and they do not bend during work. Also pay attention to the ends of the knitting needles. They should be pointed enough to easily pick up the loops, but at the same time not too sharp so as not to split the thread.
vjazem.ru
We determine the diameter of the nylon thread in the mesh fabric according to its designation in the Den and Tex standard
Determination of the thread diameter of nylon mesh fabric from Russian and Western manufacturers.
Many questions arise about the thickness and strength characteristics of nylon mesh fabrics. Let's try to figure this issue out.
It is difficult to measure the thickness of the thread using simple measuring instruments. But, depending on the structure and density of the thread, its strength will vary greatly. Indicating the diameter itself, by and large, will not tell us anything about the strength of the thread. But, nevertheless, it is easier to operate with diameter and compare nylon with fishing line or monofilament, knowing exactly the diameter.
At the moment, when indicating the structure of the threads of fishing netting (netting plates), two main units of measurement are accepted: Tex and Denier (Den). Moreover, in Russia, only the unit of measurement Tex is accepted at net knitting factories, but foreign manufacturers have heard little about this unit and the unit of measurement Den is accepted all over the world to indicate the structure of threads. This is a purely technical characteristic used to determine the density of a product or the texture of a fabric, as well as knitted fabric. Well known to our women when specifying the characteristics of hosiery.
And so, 1 Den (D) is the ratio of the mass of the thread to its length, roughly this is the number of grams of thread in 9 kilometers of its length. On the pages of the Kitayki fishing store you can find nets from foreign companies with the following designations:
- 110D/2
- 210D/2
- 210D/3
- 210D/6
The most accurate thread diameter for the Denier system can be determined by the formula:
Diameter = A*Square root (D*n/9000), where
- A - empirical coefficient for nylon = 1.5-1.6;
- D - thread density under Den;
- n - number of primary threads in a thread
For example, let's calculate the thread diameter: 110D/2 and 210D/3 using the smallest coefficient A=1.5:
- 1.5*√(110*2/9000) = 0.234 mm;
- 1.5*√(210*3/9000) = 0.396 mm.
In Russia, a similar, but coarser unit of measurement is used, Tex (from the Latin texo - fabric) - the weight of one kilometer of thread.
- 15.6 tex * 2;
- 29 tex * 3;
- 93.5 tex * 3;
- 187 tex * 2, etc.
The diameter of the thread whose density is indicated in Tex can be calculated using the same formula, but it must be divided not by 9000, but by 1000.
- 1.5*√(29*3/1000) = 0.442 mm;
- 1.5*√(93.5*3/1000) = 0.794 mm.
In the clothing industry, a thread number is used to indicate the thickness of a thread, which determines the length of one gram of thread. Thread number is 1000/tex
kitaiki.ru
How to determine the length of the yarn thread and suitable knitting needles in the absence of a label
What to do if suddenly the yarn label is lost or missing altogether?
How to determine the length of the yarn thread and suitable knitting needles?
If there are no identification marks on the yarn initially or the label is lost, you can use a simple method to determine the required amount of yarn, as well as the necessary knitting needles for knitting with this yarn.
We tightly wrap a regular school ruler with a thread of yarn in an interval of 2.5 cm without overlapping and count the number of turns that fit into this interval. Next we use the table below.
| Very thin | 18 | <2 | 32 or more | 600 or more | 2000-2500 |
| Thin | 16 | 2-3 | 27-32 | 380-550 | 1600-2000 |
| Welterweight | 14 | 3-4 | 23-26 | 240-370 | 1400-1600 |
| Average | 10-14 | 4-4.5 | 21-24 | 200-240 | 1250-1400 |
| Semi-thick | 12 | 4.5-6 | 16-20 | 170-200 | 1000-1250 |
| Fat | 10 | 6-8 | 12-15 | 110-160 | 900-1000 |
| Very thick | 8 | 8 or more | 6-11 | Less than 100 | 750-900 |
shimbashop.ru
Yarn thickness: hanima
While knitting shawls, I studied and thought about the following questions: The unit of measurement for thread thickness is tex. The thickness of the threads T in the tex system is determined by the amount of mass (weight) per unit of its length:
where g is mass (weight in g); L 0 - thread length in km; L - thread length in m.
Tex dimension - g/km.
The tex system is straight, so the thicker and heavier the threads, the greater their numerical characteristics. The fineness of the threads is indicated by a number. This is the reciprocal of tex. The fineness of the thread, indicated by the number, is the ratio of the length of the thread L to its weight g.
The number indicates the length of the thread per unit of weight (meters per gram or kilometers per kilogram). Therefore, the thinner the thread, the higher its number. The relationship between text and number is expressed as follows:
The designed thickness (in tex) or thread number is called nominal. Based on the nominal thickness or number, the weight of the material indicated in price lists and GOSTs is calculated. The actual thickness or number of threads determined during laboratory testing does not always correspond to the nominal one. The deviation of the indicators obtained during laboratory testing should not exceed 2% from those specified in GOSTs. The deviation is determined by the formulas:
where T 0 and N 0 - nominal thread thickness in tex and nominal number; Tf and Nf - actual thread thickness in tex and actual number; ΔT and ΔN - deviation of the actual thread thickness and number from the nominal one.
The thickness (fineness) of yarn and filament threads is given in table. 1-1, 1-2.
For twisted threads, it is possible to determine the nominal design thickness or nominal design number without taking into account twisting, i.e. shortening from the spiral arrangement of twisted threads, and the normal thickness (or number) taking into account twisting.
Table 1-1. Thickness (fineness) of yarn
| Fibrous composition and characteristics of raw materials | Spinning method | Thickness (fineness) of yarn in tex (N) |
| long-fiber | Grebennoy |
|
| medium fiber | ||
| short fiber and waste | Hardware | |
| long-fiber | Combed wet |
|
| long-fiber | Combed dry | |
| short fiber and noil | Carded wet | |
| short fiber and noil | Carded dry | |
| uniform thin and semi-fine; pure and mixed with chemical staple fibers | Combed for fine wool | |
| homogeneous and heterogeneous; semi-rough and rough; pure and mixed with chemical staple fibers | Combed for coarse wool | |
| homogeneous and heterogeneous; short, thin and semi-thin; pure and mixed with cotton and man-made fibers; combing waste, | Hardware for fine wool | |
| heterogeneous short; semi-rough and rough; pure and mixed with cotton and chemical staple fibers; combing waste, scrap | Hardware for coarse wool | 670-125 (1,5-8,0) |
| Natural silk: | ||
| waste from cocoon reeling, twisting and defective cocoons, waste from combed spinning | Grebennoy | |
| Grebennoy | ||
| Hardware | ||
| Chemical staple fibers |
When twisting threads of the same thickness, the nominal design thickness or number is determined by the formula:
where T r is the nominal design thickness of the thread in tex; T 0 - nominal thickness of a single thread in tex;
N p - nominal settlement number; N 0 - nominal number of a single thread; n is the number of twisted threads.
Table 1-2. Thickness (fineness) of filament threads:
| Fibrous composition | Thread type | Thickness (fineness) of threads in tex (N) |
| Natural silk: | ||
| silkworm | Raw silk | 2,3-1,5(429-643) |
| oak silkworm | Raw silk | |
| Man-made fibers | ||
| Synthetic fibers | Flat twist filament yarns | |
When twisting two threads of different thicknesses, the nominal calculated thickness (fineness) is determined by the formulas:
To calculate the normal thickness or fineness, the amount of twist must be determined, as a result of which a twisted thread of length L 2 is obtained from threads of length L 1.
Hence the normal thickness Tn and fineness NH of the thread are equal:
For some calculations it is necessary to know the diameter of the thread. With the same thickness in the tex, threads from different fibrous materials, with different degrees of straightening and orientation of the fibers, with different intensities of twist compressing the fibers in the threads, have different volumetric weights and unequal dimensions of the visible diameter.
Since determining the actual diameter of the thread under a microscope is time-consuming, the diameter of the thread is usually calculated by calculation. The weight of the thread g is found by multiplying its volume by the volumetric weight β (weight divided by the volume measured along the outer contour):
Conventionally taking the thread as a regular cylinder, we can write:
Solving the equation for diameter d, we have:
Taking:
we obtain the final formula for the calculated thread diameter:
Purpose and objectives of the work:
Purpose of the work - To study various methods for determining the linear density of threads and sewing threads.
The task of the work is to become familiar with the structure and operating principle of the equipment used.
Theoretical justification of the work:
The thickness of threads and sewing threads is usually assessed indirectly and by characteristics: linear density, trade number (symbol) and diameter.
The linear density of the threads is directly proportional to their cross-sectional area (i.e., the larger the numerical value of the linear density, the thicker the threads) and is defined as the ratio of the mass of the threads, g, to their length, km
T = m/I g/km (1)
Linear thread density. There are nominal 1 o, actual Tf, conditional G,s calculated Gr and resulting Tk linear thread densities.
Nominal is the linear density of single-strand yarn or thread planned for production in production.
The actual linear density of single-strand yarn or multifilament yarn, determined experimentally in the laboratory, is called the linear density.
The calculated linear density is calculated for caned threads in which its individual components are not subject to joint twisting.
The resultant is the linear density of twisted yarn or threads made of threads of the same or different thicknesses, calculated taking into account their twisting. For a single twisted thread consisting of yarn(s) of the same thickness.
Description of the laboratory setup:
To calculate the linear density of threads, it is necessary to determine their length and mass. According to GOST 6611.0--93, a certain number of skeins of threads are unwound from samples of packages - skeins with a length of 5, 10, 25, 50, 100 or 200 m. To unwind the threads into skeins of the required length, a device called a chainsaw is used. The skeins obtained on reels are usually used to establish the strength of the threads, and then their mass is determined on a technical or analytical balance or on a textile weight quadrant and the actual linear density of the threads is calculated using formula (1)
One of the most common devices for unwinding threads into skeins of the required length is the automated reel MPA-1M, produced by the Ivmashpribor plant. The device consists of a crown 4 (Fig. 24), an electric motor 7 with a drive to a counting mechanism 3, thread spreaders 2 and thread guides /. The thread distributors and thread guides are mounted on metal stands 8 mounted on the reel table 10; There are also pins 9 installed on the racks (on the left) for putting packages of threads on them.
Crown 4 consists of six blades, one of which has two spokes on hinges, closed by couplings.
When the couplings are shifted towards the crown blade, the upper parts of the spokes can bend at the hinges, thereby reducing the perimeter of the reel, which makes it easier to remove skeins of thread. With the spokes of this blade positioned straight, the perimeter of the reel is 1 m.
A block 5 is mounted on the sleeve 6, connected by a belt drive to the electric motor block. Threads from packages placed on pins 9 are tucked into the eyes of thread guides 1, into thread spreaders 2 and secured by springs located on one of the blades of the reel crown. The thread guides, mounted on the rods of the thread spreaders 2, during the operation of the reel, perform a slow reciprocating movement in a plane perpendicular to the passage of the threads. The spreader receives reciprocating motion from a spring located at one end of its rod in the sleeve, and a roller attached to the other, curved end (not shown in the figure).
The counting mechanism 3 consists of a gear wheel on which there is a reading scale with 100 divisions. For one revolution of the crown 4, the scale moves relative to the fixed pointer by one division. Since the perimeter of the crown of the reel is 1 m, the number of divisions shown on the scale by the arrow corresponds to the number of meters of threads wound on the crown.
Five skeins can be wound on the crown at the same time. Crown rotation frequency -- 200 rpm. To automatically stop the reel after winding threads of a given length (25, 50 and 100 m) on its crown, there is a special mechanism.
Weighing textile quadrants are dial scales that work on the principle of equilibrium of a three-arm lever. The mass of the material is indicated on a graduated scale and is determined by the angle of deflection of the lever with the indicating arrow from the initial equilibrium position.
A general view of the weight textile quadrant is shown in Fig. 25. A three-arm lever is attached to the axis 3 of the rack 6. A hook 2 is suspended on the first arm/lever, an arrow 11 (weight indicator) is attached to the second arm 13, and a balancing weight is attached to the third arm 4. On a scale of 12, using the arrow //, the mass of the thread is determined. The rack 6 is mounted on a stand 9 with set screws 7, 8 and a level 10. Before determining the mass of the threads, the quadrant is set according to the level. In this case, arrow 11 should be at the zero mark of the scale.
To determine the mass, a skein of threads (skein) is hung on hook 2 and, placing a finger on the edge of the scale, opens the fork lock 15, which serves to hold the lever in its original position when hanging a skein of threads on the hook.
Methodology of work
Determine the actual linear density of single-strand cotton yarn using a reel and a textile weight quadrant.
Based on the combined test results, calculate the average linear thread density and unevenness along it.
Determine the diameters of the tested threads by calculation.
Using one of the known experimental methods, determine the diameter of cotton sewing threads.