JP2002038342A - Apparatus for yarn quality control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge the variation of a quality control of yarns by detecting and monitoring both a short-term fluctuation of a yarn tension and a long-term fluctuation of the yarn tension. SOLUTION: This apparatus for the yarn quality control comprises a tension detector 12 for detecting the yarn tension, means (13, 15, 17 and 19) for determining the evenness value (CV%) in a short and means (14, 16, 18 and 20) for determining the evenness value (CV%) for the long term from data of the detected yarn tension and an abnormality judging means for individually judging the abnormality in the respective evenness values (CV%).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to not only instantaneous abnormalities but also instantaneous abnormalities in a false twisting machine or the like by obtaining abnormalities of a processed yarn from a short-time uniformity value and a long-time uniformity value.
The present invention relates to a yarn quality management device capable of detecting an abnormality even with a fluctuation in a long cycle.

[0002]

2. Description of the Related Art Drawing false twisting machines (hereinafter referred to as false twisting machines)
Has a large number of false twisting units, and performs false twisting by running while applying twist and tension to the yarn with a nip twister (false twisting device) of each false twisting unit. The nip twister is composed of two endless belts that cross each other and contact each other, and the yarns run while rotating both belts so as to sandwich the yarn between the belts, and give a false twist to the yarn. The untwisting tension of the yarn immediately downstream (untwisting side) of the nip twister greatly depends on the quality and properties of the processed yarn. Therefore, each false twisting unit is provided with a measuring device for detecting the yarn tension on the untwisting side of the nip twister. The detected tension of the yarn on the untwisting side is used for feedback control of the tension by adjusting the contact pressure of the belt of the nip twister or adjusting the speed of the belt.

[0003] The detected yarn tension is also used for evaluating the yarn. In conventional yarn quality control methods,
For all false twist units, set the upper and lower thresholds around the common target value of feed hack control, apply low-pass filter processing to the detected tension value, and compare with the threshold to determine abnormality. I was

[0004]

Even when the feed hack control is performed as described above, it is caused by the difference in the supply yarn, the variation in the contact pressure of the nip belt, the degree of wear of the nip belt, the position of the yarn with respect to the belt, and the like. Thus, in practice, the average tension value of each false twist unit remains slightly different. Therefore, in the case of the conventional yarn quality control method as described above, in order to prevent erroneous determination of an instantaneous tension fluctuation within an allowable range as abnormal, a threshold for defining a normal range around the target tension value. It was difficult to set the value too strictly. That is, it is necessary to set the threshold value in consideration of the variation in the average tension value between the weights, and there is a problem that high-precision quality control (abnormality determination) cannot be performed. For false twisted yarn, even if the average tension value itself is slightly offset upward or downward,
This is not a problem if the amount of the change is small, but there is a demand to detect the change in tension instantaneously due to, for example, untwisting as strictly as possible because it causes uneven dyeing.

Therefore, as a second quality control method, a uniformity (CV% or U%) indicating the magnitude of variation with respect to the average value is calculated for each single specific period, and is compared with a threshold value. It has been proposed to perform an abnormality determination by performing the following. In this case, regardless of the offset of the average tension value itself, it is possible to judge that the variation is large if the variation amount is large, so that there is a merit that an instantaneous tension variation that causes uneven dyeing can be detected. With regard to the false twisted yarn, for example, due to a supply yarn (yarn supply package), a fluctuation that is permissible in a short period may occur continuously over a long period of time. However, in the second method, since the uniformity is calculated only for a single period (short period) and the abnormality is determined, a large change in tension in a short period can be detected, but is allowed in a short period. It was not possible to detect such an abnormality that such fluctuations continued over a long period of time.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention has been improved and eliminated, and it is possible to detect instantaneous tension fluctuations in a short period of time with high accuracy, and to suppress a not so large fluctuation. An object of the present invention is to provide a quality control device capable of expanding a variation of yarn quality control by enabling detection of an abnormality that continues over a long period of time.

According to the present invention, there is provided a tension detector for detecting a tension of a yarn, and a means for obtaining a short-time uniformity value from the detected tension data of the yarn. And a means for calculating a uniformity value for a long time, and an abnormality determining means for determining an abnormality based on each of the uniformity values. As described above, by detecting and monitoring the instantaneous tension fluctuation and the long-term tension fluctuation of the yarn, it is possible to detect the momentary abnormality of the yarn quality and the abnormality in a long cycle, and to perform quality control. Variations are expanded, and leakage of abnormal yarn detection is reduced.

[0008] The means of claim 2 adopted by the present invention is:
2. The yarn quality control device according to claim 1, wherein the abnormality determining means determines the abnormality in the short-time uniformity value and the long-time uniformity value individually. According to the present invention, it is possible to individually detect an instantaneous abnormality in yarn quality and an abnormality in a long cycle.

According to a third aspect of the present invention, there is provided a tension detector for detecting the tension of the yarn of the false twisting machine, a means for obtaining a short-time uniformity value from the detected tension data of the yarn, and a length. Means for determining a time uniformity value; and abnormality determining means for individually determining an abnormality in each of the uniformity values. The false twisting machine includes a false twisting device for giving false twist to the yarn, and an upstream of the false twisting device. A yarn quality control device comprising a heater for heating and cooling the yarn on the side and a cooling plate.
According to the present invention, in the yarn false twisting machine, the claim 1 is provided.
It is possible to obtain the function and effect of the invention of (1).

According to a fourth aspect of the present invention, there is provided the yarn quality control device according to the third aspect, wherein the false twist device is feedback-controlled based on the detected yarn tension data.
According to the present invention, in the yarn false twisting machine, the claim 1 is provided.
In addition, it is possible to obtain a working yarn with stable yarn quality by controlling the false twisting device based on the result of the yarn tension detection. Further, the average value of the detected tension values of all the weights can be maintained substantially constant by the feedback control, so that the abnormality determination of the uniformity in a short time and a long time can be performed more accurately.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below with reference to the embodiments of the invention shown in the drawings. FIGS. 1 to 6 relate to an embodiment of the present invention, and FIG. 1 is a schematic side view showing an entire configuration of a false twisting machine.
FIG. 2 is a block diagram of the abnormality determining means. FIG. 3 is for explaining the uniformity value (CV%), and FIG.
Is a drawing showing an average value, FIG. (B) is a drawing showing a variation in yarn tension, and FIG. (C) is a drawing showing a uniformity value (CV%).
4A and 4B are diagrams for explaining the quality control method of the yarn. FIG. 4A is a drawing showing the fluctuation of the tension and the upper and lower limits thereof, and FIG. CV%). FIG. 5A is a drawing showing the tension value detected by the actual detector, FIG. 5B is a drawing showing the uniformity value (CV%) of the long-term variation in the tension of the yarn, and FIG. (A)
Is a drawing showing the uniformity value (CV%) of short-term yarn tension fluctuation, and FIG. (B) is a drawing showing the short-term yarn tension fluctuation uniformity value (CV%) at another time. is there.

As shown in FIG. 1, each false twisting unit 1 of the false twisting machine includes a yarn (filament yarn) Y unwound from a yarn supply package (POY or the like) 2 mounted in multiple stages on a creel stand. A first feed roller 3 running upward, a primary heater 4 for heating the yarn Y in the middle thereof, a cooling plate 5 for cooling the heated yarn Y and fixing the twist, and twisting the yarn Y. Nip twister 6 and yarn Y
A second feed roller 7 for moving the yarn Y downward, a secondary heater 8 for heating the yarn Y to stabilize the twist, and a winding device for winding the yarn Y around the winding package 9 in the above order. It is arranged from the upstream side of the yarn Y. A plurality (three in the example of FIG. 1) corresponding to the plurality of false twist units 1
(Winding package 9) is configured in multiple stages in the vertical direction. As means for detecting the tension of the yarn Y, a tension detector 10 is provided between the first feed roller 3 and the primary heater 4, and a tension detector 11 is provided before and after the nip twister 6. And 12 are provided. The tension detector 10 outputs an electric signal (analog voltage) corresponding to the tension of the running yarn Y. For example, the tension detector 10 includes a distortion element, and outputs an electric signal corresponding to the displacement of the yarn guide that comes into contact with the running system. Can be used.

FIG. 2 is a block diagram showing tension abnormality judging means of the yarn quality control device according to this embodiment. As shown in the figure, the abnormality determination means samples the untwisted tension detection signal detected by the tension detector 12 downstream of the nip twister 6 at predetermined intervals (for example, 20 ms) and stores the data. , CV values are calculated. The tension abnormality determining means includes a circuit for determining a short-time (for example, 1 s) tension abnormality and a circuit for determining a long-time (for example, several tens to several hours) tension abnormality. Buffer circuits 13 and 14 for storing the sampled tension values, CV% calculation circuits 15 and 16 for calculating the CV% value from the stored tension values,
Comparison circuit 17, 1 for comparing% value with reference value (threshold value)
8 and count circuits 19 and 20 for counting the number of times that the comparison circuits 17 and 18 determine that there is an abnormality and issuing an alarm. The circuit configuration and determination of these determination means are incorporated in a microcomputer (not shown), so that short-time processing and long-time processing are automatically performed in parallel. Further, the abnormality determination means can set and input a plurality of equality calculation periods (time or sampling points).

FIG. 3 is a diagram for explaining the concept of the CV value. First, as shown in FIG. 3A, an average value Tm of the detected tension is calculated. And this average value Tm
Is applied to the following Expression 1 to calculate CV%.

(Equation 1) In Expression 1, Tm: average tension value of N pieces of data Tx: individual tension value N: number of measured data ：: sum of N pieces of data The CV% obtained by the equation 1 is as shown in FIG. 7C, and corresponds to the waveform of the actually detected tension shown in FIG. By calculating the CV%, the detected tension value for the detected specific period is calculated as follows.
It is possible to know the magnitude of the variation with respect to the average value.

FIG. 4 shows a method for judging an actual yarn tension abnormality. As shown in FIG. 1A, it is important that the tension of the yarn detected by the tension detector 12 falls within the range between the upper limit and the lower limit. Further, in this embodiment, the short-term and long-term C
V%, respectively, that is, CV% is calculated over a plurality of different time widths (sampling points), and each CV% is calculated.
It is determined whether V% is within the range between the upper limit and the lower limit. That is, as shown in FIG. 2, when the CV% calculated for the short term and the long term are compared with the upper and lower reference values (thresholds), and the CV% value is out of the threshold. Generates an alarm (alarm) each time, or issues an alarm when the number of times exceeding the threshold reaches a predetermined number or more. Thus, by comparing the CV% value in the short term and the long term with the predetermined threshold value to determine the abnormal tension, it is possible to determine the abnormal tension with higher accuracy. Note that C
The threshold value (CV% upper limit value and / or CV% lower limit value) serving as a criterion of V% can be separately set and input for a short period and a long period.

In the case of false twisted yarn, for example, fluctuations that are permissible in a short period of time may occur continuously over a long period of time due to a supply yarn (yarn supply package). In the method of calculating the degree of uniformity only for a single period (short period) and performing the abnormality determination, it is impossible to detect such an abnormality. However, according to the embodiment of the present invention, since the instantaneous tension fluctuation of the yarn and the long-term tension fluctuation are detected and monitored, fluctuations that are permissible in a short period are over a long period. If there is an abnormality that continues over a long period, it is possible to detect the abnormality by monitoring a long-term fluctuation in tension. Therefore, both the instantaneous abnormality of the yarn quality and the abnormality in a long cycle can be detected, the variation of the quality control is expanded, and the leakage of abnormal yarn detection is reduced.

Further, in parallel with the above-described abnormality determination of CV%, the yarn quality control device performs the nip twister 6 based on the tension detection value detected by the tension detector 12 immediately downstream of the nip twister 6. By always performing feedback control of the contact pressure or the rotation speed, the yarn tension is controlled to be kept within a normal range. That is, the nip twister 6 that is a false twisting device is capable of individually adjusting the contact pressure or the rotation speed of each false twisting unit 1. The yarn quality control device detects the untwisting tension detected by the tension detector 12. The contact pressure or the rotation speed of the nip twister 6 is adjusted so that is within a predetermined range. Here, the nip twister 6 is described as an example of the false twist device, but this applies, for example, to a friction type false twist device that applies false twist by contacting a yarn with a plurality of rotating disks. Is also possible.

FIGS. 5 and 6 are diagrams showing the actually detected yarn tension value and its uniformity value (CV%). FIG. 5A shows the yarn detected by the tension detector 12. FIG. 2B is a drawing showing the tension value of the sample, and FIG.
%), And FIGS. 6A and 6B show the uniformity value (CV%) in different short time periods. After the time axis 30 shown in FIG. 5A (after the yarn feed switching), as shown in FIG. 6B, the uniformity value (CV%) in a short time is not determined to be abnormal,
In the long-time CV% shown in FIG. That is, fluctuations that are permissible in a short period of time may continue for a long period of time, and may be determined to be abnormal when viewed from a long-term viewpoint. In this embodiment, even in such a case, it is determined that there is an abnormality, and it is possible to reliably detect any variation of abnormality. After the yarn supply package has been switched, the average amount of fluctuation in tension increases, but this is considered to be due to the quality of the yarn supply package itself. The switching of the yarn supply package is such that the tail of the previous yarn supply package and the beginning of the subsequent yarn supply package are connected in advance, and when the previous yarn supply package runs out, the yarn supply package is automatically switched to the later yarn supply package. It has become.

On the other hand, as shown in FIG. 6A, in a short-term yarn tension variation between 10 and 20 on the time axis, CV% exceeds the upper threshold. However,
In the long-term yarn tension fluctuation shown in FIG. 5B, no abnormality in the short-term yarn tension fluctuation appears.
This is because the abnormality of tension that cannot be detected by CV% for a long time,
This is a specific example that can be detected in a short time CV%. It is considered that such an abnormality is caused by an instantaneous change in tension due to untwisting or the like. As described above, in this embodiment, the short-time CV% and the long-time CV% are calculated at the same time, and the abnormality in the yarn tension fluctuation is determined from both.
An abnormality that cannot be detected by a single short-time CV% or long-time CV% can also be detected, and any variation abnormality can be reliably detected.

Incidentally, the present invention is not limited to the above-described embodiment, and can be appropriately changed. For example, instead of CV%, which is the ratio of the standard deviation to the average value, U%, which is the ratio of the average deviation to the average value, represented by the following Expression 2, may be used as the degree of uniformity.

(Equation 2) CV% or U% in the short term and long term described above
Is compared with a predetermined threshold value, respectively, to determine the abnormal tension. In addition, the CV% of the plurality of false twist units 1
Alternatively, an average value of U% is calculated, and a threshold value (for example, an integer multiple of the standard deviation) obtained from the average value is compared with CV% or U% in each false twist unit to determine abnormal tension. It is also possible to In this case, it is possible to centrally manage the tension of the yarns of many false twist units.

Further, the detection of the tension of the yarn has been described with respect to an example in which the tension on the untwisting side downstream of the nip twister 6 is detected by the detector 12, but as shown in FIG. The tension may be detected by the detector 10 or 11. In this case, the first feed roller 3 is of a single spindle drive type, that is, a drive motor for driving the first feed roller 3 is provided for each false twist unit 1, and the first feed roller detected by the tension detector 10 is used. The rotation speed of the first feed roller 3 may be feedback-controlled based on the yarn tension between the first heater 3 and the primary heater 4. Furthermore, in this embodiment, the case where an abnormality is determined by obtaining a uniformity value for two times (short time and long time) has been described. It is also possible to make an abnormality determination.

[0022]

As described above, in the present invention,
A tension detector that detects the tension of the yarn, a means for obtaining a short-time uniformity value from the detected yarn tension data, and a means for obtaining a long-time uniformity value, and an abnormality determination is performed based on the respective uniformity values. The yarn quality control device is constituted by the abnormality determining means that performs the instantaneous yarn quality fluctuations and the long-term tension fluctuations. In this case, the abnormality can be detected, the variation of quality control can be expanded, and the leakage of abnormal yarn detection can be reduced. Further, it is possible to perform feedback control based on the uniformity value obtained as described above.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an entire configuration of a false twisting machine according to an embodiment of the present invention.

FIG. 2 relates to one embodiment of the present invention, and is a block diagram of abnormality determination means.

FIG. 3 is a diagram illustrating a uniformity value (CV) according to an embodiment of the present invention.
%), The figure (A) is a figure showing the average value, the figure (B) is a figure showing the fluctuation of the tension of the yarn, and the figure (C) is a figure showing the uniformity value (CV%). It is a drawing.

FIG. 4A relates to an embodiment of the present invention, and FIG. 4A shows a variation in tension and its upper limit and lower limit (threshold).
And FIG. (B) shows the uniformity value (CV) of the yarn tension fluctuation.
%).

5A and 5B are specific examples showing a variation in the tension of the yarn according to one embodiment of the present invention. FIG. 5A is a drawing showing a tension value detected by an actual detector, and FIG. 3 is a diagram showing a uniformity value (CV%) of typical yarn tension fluctuation.

FIG. 6 is a specific example showing a yarn tension variation according to one embodiment of the present invention, and FIG. 6 (A) is a drawing showing a short-term yarn tension variation uniformity value (CV%). (B) shows the uniformity value (CV) of the short-term yarn tension fluctuation at another time.
%).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... False twisting machine, 2 ... Yarn supply package, 3 ... 1st feed roller, 4 ... Primary heater, 5 ... Cooling plate, 6 ... Nip twister, 7 ... 2nd feed roller, 8 ... Secondary heater, 9 ... winding package, 10-12 ... tension detector, 1
3: short-term buffer circuit, 14: long-term buffer circuit,
15 and 16 CV% calculation circuit, 17 and 18 comparison circuit, 19 and 20 frequency counter circuit

Claims (4)

[Claims] 1. A tension detector for detecting a tension of a yarn, a means for obtaining a short-time uniformity value from a detected tension data of a yarn, and a means for obtaining a long-time uniformity value, A yarn quality management device comprising: an abnormality determining unit that determines an abnormality based on the thread quality. 2. The yarn quality control device according to claim 1, wherein the abnormality judging means judges the short-term uniformity value and the long-time uniformity value individually. 3. A tension detector for detecting a tension of a yarn of a false twisting machine, a means for obtaining a short-time uniformity value from the detected yarn tension data, and a means for obtaining a long-time uniformity value. The false twisting machine comprises a false twisting device for giving a false twist to the yarn, a heater for heating and cooling the yarn on the upstream side of the false twisting device, and A yarn quality control device comprising a cooling plate. 4. The yarn quality control device according to claim 3, wherein the false twist device is feedback-controlled based on the detected yarn tension data.