CURLY CONTROL IN FILAMENT YARNS
All chemical fibers are slightly crimped, meaning they are not straight like glass fibres. It shows fluctuations of different sizes. Textured filament yarns are crimped. The crimp measurement describes the number and size of these crimp waves.
The filament is subjected to a low prestress in the torsion scale (corrugation scale). The filament thus has a straight axis, but does not lose its curvature. Under this force, the filament length is measured ( L1); further, the bends of the fiber are counted as shown in the figure above. The force is increased until the folds on the filament are removed and the filament becomes straight. However, this force should not extend the filament itself. The height measured in this way is defined as L2.
CURLY CONTROLLER ( TEXTURMAT DEVICE )
Parts of the Texturmat device:
1- Main body
2-Precision balance
3-Magazines
4-Process control computer and printer
5- Hot water boiler for boiling tensile test
6-Hot air oven for Texturmat tests
7-Spindle
Measurement with Texturmat Device
In order to be able to measure in the Texturmat device, the material to be measured is skeined on a spinning wheel with a circumference of 1 meter. In order to provide equal test conditions, large quantities of filament yarn must be wound. When filament yarn is skeined, the hank thickness should be 2500 Dtex (2250 denier). A pre-tension must be given to the filament yarn while winding the hank. This is accepted as 1g/tex.
After the filament yarn is wound on the spinning wheel, its curliness is not fixed yet. In order to stabilize the curl, the hanks are kept in a hot air oven at 10ºC for 120 minutes without hanging any weight on them (PA and PES yarns) to ensure compliance with the conditions. In this way, the formation of folds is aimed.
Oven temperature:
1ºC for 120-PA-PES yarns
2- 100ºC for acetate yarns
3-It is 80ºC for acrylic yarns.
The filament yarns removed from the oven are kept in standard climate conditions (20ºC ± 2 temperature and 65 ± 2 % relative humidity) for 12 hours. The heating cabinet has a slot to sit on the hasp stand. More freckles on this coffee table it is first hung and placed in the oven. The part where the texturmat device will be placed on the coffee table is made in the form of a drawer. The drawer is pulled out and driven back in by placing a coffee table on it. The black handle button located in front of the coffee table drawer is turned clockwise and fixed from the top. After that, the tool is ready for operation. When the main switch is turned on, position (1) comes across the measuring fork. After that, the experiment starts by pressing the "START" button. There is a 40 second cooldown before the first movement of the measuring fork. During this time, the device resets all the timer and the remote control to the initial setting. In the first measuring period, the length (Lg) of the drawn filament yarn is measured and the printer writes the length (Lg). Then the stand rotates to bring the second hank to the measuring position. Then the Lg lengths of all hanks are printed by the printer. After the measurement of Lg (length of drawn yarn) is finished, the second period, Lz (length after curling), begins to measure. The measurement value is written by the printer directly after reaching the length Lz. When measuring the Lz value, the prestress weight (Pz) 2.5 cN is applied. In the third period each hank is first loaded with a weight of Pb (= 25 cN). It remains under this weight for 10 seconds.
In the fourth period, the Lb value is measured by the bias weight. The device signals the end of the experiment with an audible signal.
Measured values
The values measured with the Texturmat device are used in the calculations of crimp shortening, crimp modulus and crimp persistence.
Curl Shortening(%CC;EK)
The ratio of the difference between the length of the drawn yarn (Lg) and the length (Lz) after curling to the length of the drawn yarn (Lg) gives the curl shortening.
Lg-Lz
Curl shortening is calculated with the formula (%CC) = --------------------- x 100.
Lg
Curl Modulus (% CM; KK)
It is the ratio of the difference between the length Lg of the drawn yarn and the length Lf of the drawn yarn with a given tensile load of 25 grams to the length of the drawn yarn.
Lg-Lf
The fold modulus is calculated with the formula (%CM) = ------------------------- x 100.
Lg
Fold Persistence (%CS;KB)
The difference between the length Lg of the drawn yarn and the length Lb of the drawn yarn with a certain tensile load of 2.5 grams; It is the ratio of the difference between the length Lg of the drawn yarn and the length Lz after crimping.
Lg-Lb
The curl persistence is calculated with the formula (%CS) = % = --------------------- x 100.
Lg- Lz
Oil amount control
Determination of % Oil Content in Yarn
During the texturing of the filament yarn, texture oils and oils in the POY (pre-drawn partially oriented yarn) yarns are used in order to reduce friction and reduce static electricity. With the determination of oil in filament yarn, it is determined whether the oil rate in POY yarns is at the desired rate.
Test Method
1-The bobbins to be tested for oil are wound on the spinning wheel (approximately 2 kg).
2-The position numbers of the coils are written in the 'oil test book'.
3- The hanks, which are wrapped in the spinning wheel, are weighed by putting them into the beaker (after taring) on the precision scale.
4-The yarn weights of the hanks are written according to the positions written in the oil test book.
5- Separate beakers for each hank of yarn weighed on a precision scale are weighed on a precision scale. The weight of the empty beakers is written in the 'oil test book'.
1-The hanks are put into the separating funnels in order.
2-The bottom of the heater is opened (150ºC) .
3- With the help of a glass rod, the hanks are compressed towards the bottom.
4-Approximately 20 mg of petroleum ether, which is a degreasing agent, is poured into the separating funnels.
5-Thread hanks in petroleum ether for about 10 minutes. wait for the oil to dissolve.
6-10 min. Finally, the yarn hanks are shaken in the separating funnel with the help of a hook.
7-Skeins of yarn are drawn towards the mouth of the separating funnel and left in the mouth of the funnel.
8-After filtering, the last ether in the hanks is squeezed with the help of tweezers.
9-The empty beakers, which are weighed in order, are placed on top of the heater and under the taps at 100ºC without mixing the order.
10-The taps are opened. The petroleum ether poured into the beakers remains on the heater until it evaporates from the beaker and evaporates.
11-After the petroleum ether evaporates, the bottom of the heater is turned off.
12- The oiled beakers on the heater are placed on the tray and left to cool.
13-After cooling, oily beakers are weighed again on a precision scale and the formula is applied.
AB
Oil test formula = -------------- x100
C
A=Weight of the beaker containing the oil sample (g)
B = Weight of the initial empty beaker (g)
C=weight of yarn sample (g)
Evaluating Test Results
The values obtained from the test results are controlled with the values in the filament yarn production plan, ensuring that the filament yarn is produced with high quality and efficiency.
YARN NUMBER REINFORCEMENT (METER REINFORCEMENT)
In order to cut the threads in certain lengths, tools called spinning wheels are used to measure the length. The yarn whose number is to be determined simultaneously winds 5, 7, 10 samples in 1m steps from the bobbin or cop to the reel at a certain length. The specific number of revolutions on the reel gives the specific length value.
If the yarn to be sampled is to be expressed as tex, the spinning wheel with a circumference of 1 meter is wound 100 turns, if the number is to be expressed as denier, 90 turns. More than 1 sample can be wound at the same time by placing sample threads on the device. Their length will be the same.
PRECISION SCALE
Yarns whose length values have been determined are weighed on a scale with 1 mg sensitivity and their weights are found.
With this system consisting of precision scale, main unit and printer, the hank or yarn of a certain length is put on the pan of the precision scale and its number is determined. The scale sends the measured weight as data to the main unit. The main unit, on the other hand, displays the yarn number in Nm, dTex, denier units on its screen according to the previously set parameters. In addition to the yarn count, the roving and sliver count can also be measured. The numbers can be calculated by converting them to each other.
CONTROL OF STRENGTH AND LENGTH OF BREAK
Purpose of Detection of Yarn Strength Deviations
Yarn strength is the resistance of the yarn to an applied load. Strength is an important factor in the yarn. In order to increase efficiency, especially during the use of the produced yarn, the strength value in the yarn should be high; reduces time loss, increases quality and aesthetics. It reduces yarn breaks and machine downtimes and reduces costs.
We can list the factors affecting yarn strength as follows:
1-Fiber length
2-Fiber fineness
3-Distribution of molecules in the thread structure
4-The raw materials that make up the yarns
5-Irregularity rate
6-Twist
Strength is generally determined by breaking strength and percent elongation values. In addition to these, there are some parameters that determine the strength of the yarn. The sum of these gives information about the strength of the yarn.
Strength in yarn is generally examined under the following headings:
1- Tensile strength
2-Elongation percentage
3-Breaking length
4-Breaking load
5-Breaking voltage
6- Determination of strength in yarn
Tensile Strength
breaking strength of yarn; It is the ability of the yarn to withstand tension or its breaking strength. This can also be called the breaking tension of the yarn. It is the maximum resistance that occurs in a tensile strength test advanced to rupture. Tensile strength is measured in grams per denier or grams per tex and is expressed as force per unit yarn count.
1- Denier strength: The grams or weight (in g/den) required to break one denier yarn or fiber.
2-Tex strength: grams or weight (g/tex) required to break one tex yarn or fiber.
Elongation Percentage
It is a measure of the degree of elongation of a yarn under tension.
The elongation rate is expressed in three ways.
1-In length
2-As a percentage of the initial length
3-As part of the first length
When force is removed from a product that has been extended to its critical point of extension, it quickly returns to baseline. After this point, it is not possible to return to the starting point, as stretching will be provided by breaking the macromolecular chains. The stretching or elongation of a yarn by the effect of stretching to the breaking point indicates its extensibility or extensibility. The change in length or deformation of the yarn after the application of the tensile force is measured as a percentage of its original length.
Breaking Length
It is the length at which a thread breaks with its own weight. In filament yarns, whether the molecular structure is smooth or not is one of the most important factors affecting the breaking length. If the linear areas (where the molecules are located properly) are high, the breaking length is high; If the amorphous areas (where the molecules are dispersed) are high, the breaking length is low. Break length is a measure that makes it possible to compare different control materials with different numbering systems with each other. Rkm is the abbreviation of breaking length for breaking kilometer.
Breaking Load
It is the load required to break the yarn that develops the breaking tension. The correct way to express it is "Newton". The breaking load, if expressed in grams of weight or pounds of weight, will vary according to local conditions.
TAKING YARN SAMPLES
The sample yarns to be controlled are taken from the machines sequentially. In continuous laboratory controls, it is sufficient to take 3 samples from each coil in hand-controlled machines and 5 samples in automatic controlled machines.
The number to be used in the yarn count should always be taken as the measured number.
STRENGTH DEVICE
The measuring device used in strength tests must meet the conditions given below.
1- Applying a constant load increase to the sample or providing a constant amount of elongation to the sample at the same time,
2-It automatically measures the amount of elongation in the yarn under the applied force,
3- Calculating and showing the load required to break the sample,
4- Measuring and showing the elongation up to the maximum load,
5-Holding the thread securely, thus preventing thread breakage as a result of clamping in the jaws,
6- It should be in a way to load the maximum load on the sample in 20 ± 3 seconds.
Various tools and devices are used to determine the strength of the yarn. Today, besides the modernized machines, there are also old model strength test devices that are still used.
STRENGTH DETERMINATION IN FLAMENT YARN
To determine the filament yarn, strength, elongation at break and breaking loads at the same time according to the principle of equal test speed;
1-All samples are conditioned before the control.
2- According to the yarn type, the previously adjusted program is selected,
In 3-POY yarns; distance between clamps 200 mm ±1 mm; test speed 1500 mm/min; pre-tension 0.05 g/tex
4-Textured, twisted, FDY etc. in threads; distance between clamps 200mm±1mm; test speed yarn break time 20 sec. is set to be.
5-Before starting the control, 1000 meters of thread is untied from the thread surface.
6-Strength measuring device is run for each sample.
7-Strength measuring device gives the average value by making 5 shots for each sample.
Making the control:
In the measurement of yarn strength; A certain length of yarn with a certain number is placed between the two jaws of the machine, one fixed and the other moving.
An increasing force is applied to this placed thread. With the effect of this force, some elongation is seen in the yarn and the yarn breaks at any force value according to the durability of the yarn. This value is noted by reading from the instrument panel (scale) of the machine or taken as a printout. It would not be correct to define the yarn strength expression only as the maximum force that the yarn withstands without breaking. Because the yarn containing more fibers in its cross-section will withstand higher forces.
In this case, it cannot be concluded that the yarn breaking at lower strength is bad, and the yarn breaking at higher strength is good. For this reason, yarn number (linear density) should also be included in the expression of yarn strength value. Accordingly, the yarn strength value is expressed as the ratio of this measured breaking force to the yarn count (linear density) and is calculated according to the measurement units. g/tex or a cN/tex It is shown as . For yarn strength value “Rkm” The expression is widely used and this value is the length in km at which the thread breaks with its own weight when hung vertically.
The strength in the yarn is calculated as follows.
1-Strength (gram /tex) = average breaking force (gram) / measured tex
2-Strength {grams / denier) = average breaking force (grams) / measured denier
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