EP1630268A1 - Method of assuring yarn quality and yarn processing machine - Google Patents

Abstract

In a quality assurance method in the production of multifilament yarns by supplying yarns under tension through a pathway (1) in the production unit (5), where the tension in a control yarn is measured in the pathway between a receiving bobbin (20) and the production unit, the tension of the control yarn before supply into the production unit is kept constant within a predetermined range, according to a measured value, using a yarn tension regulating module (25). An independent claim is included for yarn processing machine arranged to carry out the process, having at least one receiving bobbin unloader (24) for taking off yarn from at least one receiving bobbin (20, 29) and a multifilament yarn production unit (5) into which the yarns are passed under tension via a controlled pathway (1) including a tension regulating module (25) with a tension sensor (and preferably a yarn brake and/or a controllable feeder (7)), where the tension regulating module receives a measured value of the tension from the sensor and keeps the tension constant within a predetermined range.

Description

The invention relates to a yarn quality assurance method in the production of a multifilament yarn and to a yarn processing machine for performing the yarn quality assurance method. The yarn quality assurance method comprises the steps of unwinding at least one yarn from each supply bobbin and feeding the yarns through a respective yarn path into a multifilament yarn production unit, wherein the yarns are held at a yarn tension. The yarn quality assurance method is suitable in principle for use in any multifilament yarn production process, eg also in draw-winding or weaving, but in particular for use in texturing processes, in particular false-twist texturing processes and / or air-covering processes.

Machines with an air-covering nozzle (air-covering machine) are used to continuously process filament yarns by means of an air jet (interlacing jet) into a multi-component yarn (air-covering yarn). In this case, at least one sheath thread (fancy yarn) are joined as components with a core thread. The aim of this process is to achieve as uniform as possible knotting nodes in the multi-component yarn and thus to connect the components together, whereby the multifilament yarn produced has both mechanical and structural elasticity. An example of an air-covering machine is disclosed in US 6,405,519 B1. The core thread is usually an elastomeric-containing highly elastic yarn, e.g. Lycra. The sheaths may include various fancy yarns. The yarns, ie the sheaths and the core thread, are conveyed via delivery mechanisms, e.g. Galetten, fed to an air-covering nozzle. After the multicomponent yarn has passed through the air-covering nozzle, the multicomponent yarn is taken up by a spool on which the multicomponent yarn is wound up.

The elastic yarn is positively, tangentially, by means of a supply spool, with the aid of a special delivery, unwound (tangential deduction). To perform this operation, at least one additional drive is necessary. In order to unwind tangentially the supply bobbin of the elastic yarn, it is positioned with its axis parallel to the axes of delivery mechanisms used for unwinding. If the feed bobbin is empty, the entire manufacturing process must be stopped so that the feed bobbin can be replaced. In order to interrupt the production process in case of a necessary feed bobbin change, for example when the current feed bobbin has been used up, as briefly as possible, complicated systems were developed which make an automatic supply bobbin exchange possible. Such a system is disclosed, for example, in WO 2004/035446. When tangential deduction two variants are distinguished. When free-running tangential trigger the feed bobbin sits on a freely rotating sleeve without own drive. The freely rotating trigger is only applicable at low process speeds. When driven tangential trigger the rotation of the supply spool is driven by support rollers. This driven tangential trigger is applicable for high production speeds of elastic yarns.

The sheaths may e.g. with a known Garnbearbeitungsmaschinen for processing filament yarns with a Lufttexturierdüse (Lufttexturiermaschine) are produced. Usually, the production of sheaths and processing, e.g. with the air-texturing nozzle, performed by a single machine. Such Lufttexturiermaschine is disclosed in DE 39 09 516 A1. Air texturing machines are used to consistently curl smooth structureless filament yarns. Several original yarns (core threads) can be processed into a textured yarn using effect yarns of different traditions. In this process, the filament yarns are uniformly crimped and, if necessary, arranged around the original yarns. The sheaths may include various fancy yarns. The filament yarns, ie the sheath threads and the core thread, are conveyed via delivery mechanisms, e.g. Galetten, fed to a Lufttexturierdüse. After the yarns have passed through the air-texturing nozzle, the multicomponent effect yarn (multicomponent yarn) produced is picked up by a spool on which the multicomponent yarn is wound. Before winding, the multicomponent yarn can be stretched, fixed, shrunk and / or sharpened again.

It is also known to produce the sheath threads with a yarn processing machine for performing false twist texturing processes. This process is also referred to as torsional crimping. In this case, the filament yarn is obtained between two pairs of cylinders, namely a delivery mechanism and a take-off unit, by a swirl generator a so-called false twist, which is fixed by heating the filament yarn by utilizing its thermoplastic properties in the capillary filaments. After cooling, latent torsional forces act and lead to the crimping of the produced fancy yarn.
For this purpose, the multifilament yarn (thread) is generally unwound from a supply spool, passed through a first delivery, then heated in a heater (primary heater), cooled on a cooling rail, through the swirl and a second delivery mechanism arranged behind it, a so-called deduction delivery, guided, to be subsequently wound up on a yarn package. The swirl generator serves to temporarily turn up the multifilament yarn in one operation, ie to produce a twist of the multifilament yarn, or of the individual filament yarns, by transmitting an axial torque to the filament yarns. This temporary twisting (twisted state) is called false-twisted wire (FD). By the rotation, a rotation backlog is formed, which reaches back to the heater (swirl zone), thereby enabling the twisted state of the filament yarns to be thermally fixed in front of the swirler by heating and cooling. Behind the twist donor, the twist is then resolved again. Due to the thermal fixation in the twisted state, the yarn has the desired crimped structure.

Very high production speeds are possible by using a friction twist generator as a swirl generator. In these swirlers, the filament yarn is driven directly by means of friction surfaces. Due to the smaller diameter of the thread compared to the spindle, ie, for example, a disc of a Scheibenfriktionsaggregats, a high transmission ratio between the rotation of the disc and the twisting of the filament yarn is realized. The three-axis disc friction unit is particularly well suited for this purpose. As a swirl generator are therefore mainly friction twister, in particular three-axis Scheibenfriktionsaggregate, but also so-called nip Twister, by means of crossed belt to transmit torque to the filament yarns used. Such a disk friction unit is disclosed, for example, in DE 3743708 A1. A nip twister is shown in JP 06184848 A. The twist distribution by friction allows very high rotational and thus high production speeds. If the friction conditions between the filament yarns and the swirl generator vary, ie if process fluctuations or instabilities occur, then this leads to an irregular yarn structure or defects in the yarn and thus to quality losses in the yarn produced. Such errors or disturbances can result, for example, from disturbances in the spinning, from uneven application or uneven adjustment of the spin finish on the thread surface, from temperature fluctuations during texturing or from contamination eg in the heater and / or in the cooling rail. The disturbances can cause a so-called ballooning of the yarn, which occurs especially at high rotational speeds and the associated high thread tensions. Ballooning the yarn results in an uncontrolled threadline and thread tension variations. As a result, the thread can jump over the disc surface of the twister, for example. This swirl slip leads to a rotation deficit within the swirl zone, ie the twist density, ie the number of twists per unit length of the filament yarns fluctuates. The yarn to be processed can thereby pass in sections without twisting the twister. This leads to short closed yarn sections, so-called "tight spots" and long unevenly textured yarn sections, which is referred to as "Surging". During surging, the thread tension increases abruptly, which disturbs the balance of forces in the swirl generator. Zones are created in the thread without rotation. Besides, stretching values fluctuate, staining becomes insufficient.
Texturing speeds of over 300 m / min are possible with friction twisters. The heating and cooling zones in the texturing zone are adapted in length to these texturing speeds, in order to still have sufficient heat setting to ensure the crimping. With a length of the texturing zone of a total of 5 to 6 m, the phenomenon of surging occurs particularly frequently in connection with the frictionally engaged friction twisters. In the case of non-positive swirlers according to the prior art, the generated torsional density can not be controlled very precisely, as a result of which the procedural production restriction of the surging, and thus the ballooning of the thread in the swirl zone with accompanying thread tension fluctuations, which in turn result in twisting variations, occur. The stability limit of the process is influenced on the one hand by the geometry of the texturing zone, eg its length, deflection points, thread support, etc., and on the other hand by the quality of the original material, eg its uniformity, preparation etc., ie by occurring process fluctuations.

• Dadurch, dass der Durchmesser der Vorlagespule mit der Zeit durch Abspulen des Garns abnimmt, ändert sich die Geometrie des "Ballons", der von den Garnbewegungen entlang der Spulenachse gebildet wird, entsprechend, wodurch die Fadenspannung beeinflusst wird.
• Durch Vergrößerung der Produktionsgeschwindigkeit und damit der Abspulgeschwindigkeit des Garns von der Vorlagespule vergrößern sich auf das Garn im "Ballon" wirkende Zentrifugalkräfte, was zu einer Fadenspannungserhöhung führt. Insbesondere bei Garnen aus Polyamid (PA) treten die genannten Probleme besonders stark auf.

Bei den bekannten Vorrichtungen zur Vermeidung von
Fadenspannungsschwankungen bei Texturierprozessen kann lediglich vor einem Start des Herstellungsprozesses die Fadenspannung des Garns reguliert werden.
Dies reicht nicht aus, um die beschriebenen Variationen der Fadenspannung während des Herstellungsprozesses zu vermeiden.Another factor limiting the production speed in false-twist texturing processes is the unwinding speed of the yarns, eg a partially oriented multifilament yarn (POY), from the supply spool. Higher unwinding speeds result in greater variations in the tension of the yarns (yarn tension) in the region of the yarn path after the supply spool (unwinding region). This follows from properties of the known "balloon" formed by the yarn during unwinding.
A false-twist texturing process always begins with the unwinding of a POY yarn from a supply spool. The yarn is withdrawn from the supply spool by the rotating movement of a take-off roll (delivery mechanism). The take-off roll typically includes a main engine-driven roller and a passive separation roller that determines the geometry of wraps of the yarn about the main roller. In order to avoid yarn tension variations in the unwinding region, it is known to exert a pressing force on the main roll by means of a "nip-roller", that is to say a further roller. As a result, the yarn between the main role and the other role is trapped, resulting in that the yarn with the Tangentialgeschwindigkeit the main role of the texturing process is supplied. Further, various biasing systems disposed between the supply spool and a delivery mechanism are known to increase and stabilize the yarn tension of the supply spool as it is withdrawn from the supply spool. The variations of the thread tension, eg of the POY yarn withdrawn from the supply bobbin, have essentially the following reasons:

• The fact that the diameter of the supply bobbin decreases with time by unwinding the yarn, the geometry of the "balloon", which is formed by the yarn movements along the bobbin axis changes accordingly, whereby the yarn tension is affected.
• By increasing the production speed and thus the unwinding speed of the yarn from the supply spool, centrifugal forces acting on the yarn in the "balloon" increase, which leads to a thread tension increase. Especially with yarns made of polyamide (PA), the problems mentioned occur particularly strongly.

In the known devices for preventing
Thread tension fluctuations in texturing processes can only be regulated before starting the production process, the thread tension of the yarn.
This is not sufficient to avoid the described variations in yarn tension during the manufacturing process.

It is also known from EP 0 875 479 A1 to measure and control the yarn tension of single yarns in yarn conditioning processes associated with rewinding processes, eg, oiling, dyeing or stretching yarns. The yarn tension of a yarn is measured in the yarn path after a conditioning and the yarn tension of the controlled yarn before its winding, ie at the end of the conditioning process, according to a derived from the measured yarn tension controlled variable by means of a yarn tension control module in a predetermined yarn tension range kept constant. The yarn tension control module in this case comprises a yarn brake and a controllable delivery mechanism, by means of which the yarn tension is regulated by braking and / or accelerating the yarn speed of the yarn.

The invention has for its object to provide a yarn quality assurance method and a yarn processing machine, which avoid the disadvantages of the prior art and in particular allow a high process speed with minimal downtime of the yarn processing machine.

This object is achieved by the yarn quality assurance method and the yarn processing machine of the independent claims. The dependent claims represent preferred embodiments of the invention.

• Abspulen mindestens eines Garns von jeweils einer Vorlagespule, und
• Zuführen der Garne über jeweils einen Fadenlauf in eine Multifilamentgarnherstellungseinheit, wobei die Garne auf einer Fadenspannung gehalten werden.

Erfindungsgemäß wird mindestens die Fadenspannung eines kontrollierten Garns in dessen Fadenlauf zwischen dessen Vorlagespule und der Multifilamentgarnherstellungseinheit gemessen und die Fadenspannung des kontrollierten Garns vor dessen Zuführen in die Multifilamentgarnherstellungseinheit gemäß einer von der gemessenen Fadenspannung abgeleiteten Regelgröße mittels eines Fadenspannungsregelungsmoduls in einem vorgegebenen Fadenspannungsbereich konstant gehalten.The yarn quality assurance method according to the invention in the production of a multifilament yarn has the following method steps:

• Unwinding at least one yarn from one feed bobbin, and
• Feeding the yarns over a respective threadline in a multifilament yarn production unit, wherein the yarns are held at a thread tension.

According to the invention, at least the yarn tension of a controlled yarn is measured in its yarn path between its supply spool and the multifilament yarn production unit, and the yarn tension of the controlled yarn is kept constant in a predetermined yarn tension region by means of a yarn tension control module prior to its feeding into the multifilament yarn manufacturing unit according to a controlled variable derived from the measured yarn tension.

The thread tension control module may e.g. according to the device disclosed in EP 0 875 479 A1. It is essential that the thread tension control module has an active, adjustable drive with the ability to regulate the thread tension. The measurement of the thread tension can e.g. with a yarn tension sensor comprising a strain gauge to be performed. However, it is also possible to measure and monitor the electrical power consumption of the drive. Since the friction values between the yarn and the drive are influenced by the thread tension, the electrical power consumption of the drive also varies depending on the thread tension, from which the controlled variable can be determined. Thus, as a thread tension regulation module, it may be a standard delivery plant combined with any type of thread tension regulation system, e.g. a meter measuring the electric current flowing through the delivery mechanism together with a circuit evaluating the measured current. The delivery mechanism itself acts in such an arrangement as a thread tension sensor.

With the method according to the invention, the thread tension in the Abspulregion is stabilized, so that a regular profile of the thread tension over time, regardless of the process speed and the diameter of the supply bobbin, is maintained. This ensures consistent quality of the produced multifilament yarn, eg the textured yarn, over the entire length of, for example, POY yarn on the supply spool. Furthermore, an increase in the production rate of the production process, while maintaining quality, is achieved.
The inventive method allows a complete "online" control of the thread tension when unwinding the yarn from the supply spool. The thread tension can be kept constant regardless of the quality of the yarn, the diameter of the supply spool and the selected unwinding speed. In addition to the possibility of thread tension when unwinding, when necessary to increase or decrease in a controlled manner, the thread tension can be permanently reduced, thereby enabling a higher production speed and efficiency.

Particularly advantageously, the controlled yarn is fed by means of the multifilament yarn production unit, preferably via a delivery mechanism, first to a heater, subsequently to a cooler and subsequently to an air-texturing nozzle or preferably to a swirl unit. The method according to the invention is accordingly used in false-twist texturing. When using the method according to the invention in false-twist texturing processes, the "surging" typically occurring at high process speeds is largely avoided.

The inventive method is particularly preferably used in a highly elastic yarn as the yarn to be controlled, wherein the highly elastic yarn is fed preferably via a delivery mechanism and / or at least one thread guide device, an air-covering nozzle of the Multifilamentgarnherstellungseinheit. The unwinding of the highly elastic yarn is done overhead.

The inventive method allows an overhead pulling off of the elastic yarn, since occurring yarn tension fluctuations are compensated. If the elastic yarn is removed overhead during an air-covering process, interruptions to the production process can be avoided by changing the supply bobbin. When deducting overhead, the feed bobbin does not rotate itself, thus working overhead with an immediately usable spare reserve bobbin is possible, whereby downtime of a correspondingly working yarn processing machine can be minimized. The reserve feed coil becomes symmetrical to the vertical one

Positioned axis of the yarn processing machine with the supply spool from which the elastic yarn is currently withdrawn. The free end of the yarn on the reserve supply spool is knotted with the final end of the yarn of the currently unwinded supply spool. When the yarn of the currently unwinded supply spool is used up, the yarn of the reserve supply spool is automatically withdrawn and the production process continues without interruption. Then the empty feed bobbin is replaced by a new feed bobbin, which is used as a new reserve feed bobbin, with the yarn of the new feed bobbin being entangled with that of the old reserve feed bobbin. This achieves a quasi-infinite process.

Preferably, a yarn speed of the controlled yarn is decelerated and / or accelerated by means of the yarn tension control module. By slowing or accelerating the thread speed, the thread tension can be both increased and decreased. If the measured yarn tension is recorded, the quality of the produced multifilament yarn can be subsequently evaluated and checked.

A yarn processing machine according to the invention has at least one feed bobbin receptacle configured to receive at least one supply bobbin, yarns of which can be unwound, and a multifilament yarn production unit, into which the yarns can be fed from the supply bobbins via yarn runs, each with a thread tension. According to the invention, a thread tension regulation module with a thread tension sensor is arranged in at least one controlled yarn path between the associated supply spool receptacle and the multifilament yarn production unit, wherein the yarn tension control module preferably comprises a yarn brake and / or a controllable yarn supply system. The yarn tension control module is configured to be a controlled variable of one of the yarn tension sensor derive measured thread tension and keep the thread tension in a predetermined yarn tension range constant.
With the yarn processing machine according to the invention, the yarn quality assurance method according to the invention can be carried out. The yarn processing machine according to the invention therefore provides the advantages of the yarn quality assurance method according to the invention.

In the yarn processing machine according to the invention, the multifilament yarn production unit has arranged in the yarn path one behind the other preferably a delivery mechanism, a heater and a subsequently arranged cooler and subsequently arranged an air-texturing or preferably a swirl generator. In this arrangement, the yarn processing machine is a texturing machine, ie a false twist texturing machine or an air texturing machine, in which production errors caused by thread tension fluctuations are largely excluded.

The multifilament yarn production unit preferably comprises an air-covering nozzle, wherein preferably a delivery mechanism and / or at least one thread guiding device are arranged in the yarn path in front of the air-covering nozzle, and wherein a supply coil receptacle of a controlled yarn path is set up, a highly elastic yarn of one of the Unwind spool receiver taken overhead bobbin. The delivery mechanism can already be part of the thread tension control module. The thread guide device allows the highly elastic yarn to be always fed from the same position from the thread tension control module. The latter is advantageous, in particular, when unwinding the elastic yarn from the supply bobbin, since when the bobbins are being unwound by means of a reserve supply bobbin, a break in the production process can be avoided by changing the supply bobbin. wherein the reserve supply spool can be kept ready in a further supply spool receptacle.

• Die Figur 1 zeigt den Fadenlauf in einer erfindungsgemäßen Garnbearbeitungsmaschine.
• Die Figur 2 zeigt einen Fadenlauf zwischen der Vorlagespulenaufnahme und der Multifilamentgarnherstellungseinheit mittels der ein Falschdrahttexturierverfahren durchgeführt wird.

The invention will be explained in more detail by means of embodiments with reference to the drawings.

• FIG. 1 shows the yarn path in a yarn processing machine according to the invention.
• FIG. 2 shows a yarn path between the supply spool receiver and the multifilament yarn production unit by means of which a false-twist texturing method is carried out.

The figures of the drawings show the subject matter of the invention in a highly schematic manner and are not to scale. The individual components of the article according to the invention are shown so that their structure can be well shown.

FIG. 1 shows a controlled yarn path 1 in a yarn processing machine according to the invention, by means of which an air-covering process is carried out with an elastic yarn and a yarn produced in a false twist texturing unit 3 as a cover yarn. The method according to the invention is shown here using the example of a yarn processing machine which produces a cover thread for air-covering by means of false-twist texturing. The method according to the invention and in particular the preferred embodiment of feeding an elastic yarn as a controlled yarn into an air-covering nozzle 5 as a multifilament yarn producing unit via an actively driven delivery mechanism 7 and the over-head unwinding of the elastic yarn can just as well be used in connection with the manufacture an air-textured yarn. The figure shows a possible arrangement of elements that in a Combining a false-twist texturing process with an air-covering process may be included. At the end of the texturing unit, in which the yarn to be textured, which has been unwound from a supply spool 8 via a delivery mechanism 9, has passed through a heater 10, a condenser 11 and a swirl unit 12, the textured yarn is passed around a delivery mechanism 13, before it is fed into the air conveyor. Covering nozzle 5 enters where it is connected to the elastic yarn, ie where by means of small knots, the textured yarn with the elastic yarn in a compact structure for the further process, ie essentially the winding of the finished multifilament yarn on a coil 15 is connected , The finished multifilament yarn, before it is wound onto the spool 15, is guided over a delivery mechanism 17 arranged between the air-covering nozzle 5 and the spool 15 and a thread guiding device 18. The elastic yarn is withdrawn from a supply spool 20 overhead. The elastic yarn is first passed through a thread guide device 22 and then passed over the actively driven delivery mechanism 7. This delivery mechanism 7 is part of a yarn tension control module 25. It comprises an active, adjustable drive, which is set up to control and regulate the yarn tension. Due to its drive, the delivery mechanism 7 pulls on the elastic yarn, as a result of which the elastic yarn is withdrawn from the supply spool 20 overhead. By means of a difference in the rotational speed of the delivery mechanism 17 arranged between the air-covering nozzle 5 and the spool 15 to the actively driven delivery mechanism 7, a stretch of the elastic yarn is set which is necessary for achieving mechanical stability of the produced multifilament yarn. When pulling off overhead, it is possible to unroll the yarn from the outside or from the inside of the supply spool 20. The feed bobbin 20 is always fixedly received by a feed bobbin receptacle 24. Due to the fact that the supply bobbin 20 does not rotate when it is pulled off the top, one end 27 of the yarn of the supply bobbin 20 can be connected to a beginning 28 of a yarn of another supply bobbin (reserve supply bobbin 29) which is held in a further supply bobbin receptacle 30 complete unwinding of the first feed spool 20, the reserve supply spool 29 is automatically unwound. The manufacturing process must therefore not be interrupted when pulling off overhead.
For the method according to the invention, it is particularly suitable to remove from the outside over the top, since in this case particularly high speeds can be achieved during unwinding of the yarn. When pulling off overhead, a "balloon" 31 forms, whereby the thread tension varies greatly in the Abspulregion. So that these yarn tension variations do not adversely affect the quality of the multifilament yarn to be produced, the yarn tension in the illustrated yarn processing machine is regulated by means of the yarn tension control module 25, between the supply coil receptacle 24 and the air covering nozzle 5, and kept constant within a yarn tension range. The thread tension control module 25 is arranged in the example shown between two thread guide devices 22,32, wherein one is arranged directly in front of the air-Covering nozzle 5. The elastic yarn is brought together in this thread guiding device 32 with the false-twist-textured wrapping thread, for example, and then fed to the air-covering nozzle 5 with a regulated thread tension. The thread guiding device 22 in front of the thread tension regulation module 25 is arranged in a central position in front of the actively driven delivery mechanism 7. This thread guide device 22 causes the elastic yarn in the actively driven delivery mechanism 7, regardless of which supply bobbin 20,29 is currently being used, always executed from the same position. This thread guide device 22 is "in focus" of the two feed bobbins 20,29.

In FIG. 2, a controlled yarn path 40 in a yarn processing machine according to the invention is shown between a supply spool receptacle 41 and a multifilament yarn production unit, which is embodied as a false twist texturing unit 42. The false twist texturing unit 42 has a heater 43, a cooler 44 and a swirl unit 45. From a supply spool 46, which is arranged in the supply spool receptacle 41, the yarn is fed via a delivery mechanism 48 of the false twist texturing unit 42. The delivery mechanism 48 has a main roller 49 and a separation roller 50 around which the yarn is wound. As a result of the unwinding process, the yarn forms a "balloon" 31. In the yarn path between the balloon 31 and the delivery mechanism 48, a yarn tension control module 53 is arranged. The yarn tension control module 53 comprises a yarn tension sensor 54 which measures the yarn tension, a yarn brake 55 and a controllable delivery mechanism 56. By means of the yarn tension control module 53, a controlled variable is derived from the yarn tension over which the yarn tension is kept constant within a predetermined range. This control variable may include, for example, a difference between measured thread tension and a desired thread tension. The yarn brake 55 and / or the controllable delivery mechanism 56 are controlled in accordance with the controlled variable. If, for example, the measured thread tension is too great, the speed of the yarn is braked by means of the thread brake 55. With the yarn processing machine according to the invention, the yarn tension increasing linearly with increasing process speed in the prior art can be kept at a constant value, independently of the process speed. The thread tension can be adjusted according to the needs of the downstream process of the multifilament yarn. The yarn tension is measured with the yarn tension sensor 54 and in a closed loop control the speed of rotation of the controllable delivery 56 and / or the braking force of the yarn brake 55 according to the measured yarn tension. When the diameter of the supply spool 46 decreases, the yarn tension is automatically adjusted by the yarn tension control module 53 via the control loop so that it corresponds to a desired value during the entire production process, ie is kept constant within a predetermined yarn tension range.

The yarn tension control module 53 therefore regulates the yarn tension with which e.g. the POY yarn of a multifilament yarn making unit, e.g. a false-twist texturing unit 42 is supplied to a predetermined value independent of an increase in the process speed, thereby eliminating one of factors limiting an increase in the process speed in false-twist texturing.

Proposed is a yarn quality assurance method and a yarn processing machine, arranged for carrying out the method according to the invention, with at least one feed bobbin receiving 24,30, adapted for receiving at least one feed bobbin 20,29, of which yarns are unwindable, and a Multifilamentgarnherstellungseinheit 5, in which the yarns can be fed from the feed bobbins 20,29 threadlines, each with a thread tension. According to the invention, a thread tension regulation module 25 with a thread tension sensor is arranged in at least one controlled threadline 1, between the associated supply package receptacle 24 and the multifilament yarn production unit 5, wherein the thread tension regulation module 25 is arranged to derive a control variable from a thread tension measured by the thread tension sensor and to adjust the thread tension in a predetermined one Keep the thread tension range constant.

The invention is not limited to the embodiments given above. Rather, a number of variants are conceivable, which make use of the features of the invention even with fundamentally different type of execution.

Claims (7)

Yarn quality assurance process in the production of a multifilament yarn with the process steps - Unwinding of at least one yarn from each supply bobbin (20,29,46), and Feeding the yarns in each case via a threadline (1,40) into a multifilament yarn production unit (42,5), wherein the yarns are held at a thread tension,
characterized in that
at least the yarn tension of a controlled yarn in the yarn path (1,40) between its supply bobbin (20,46) and the multifilament yarn production unit (42,5) is measured and the yarn tension of the controlled yarn prior to its feeding into the multifilament yarn production unit (42,5) according to a controlled variable derived from the measured yarn tension is kept constant by means of a yarn tension control module (25, 53) in a predetermined yarn tension range. Yarn quality assurance method according to claim 1,
characterized in that
by means of the multifilament yarn production unit (42) the controlled yarn, preferably via a delivery mechanism (48), first a heater (43), then a cooler (44) and subsequently an air-texturing or preferably a swirl unit (45) is supplied. Yarn quality assurance method according to at least one of claims 1 to 2,
characterized in that as a controlled yarn, a highly elastic yarn, preferably via a delivery mechanism (7) and / or at least one thread guide means (22,32) an air-covering nozzle (5) of the Multifilamentgarnherstellungseinheit is supplied, wherein the unwinding of the highly elastic yarn done over head. Yarn quality assurance method according to any one of claims 1 to 3,
characterized in that by means of the yarn tension control module (25, 53) a yarn speed of the controlled yarn is decelerated and / or accelerated, and / or that the measured yarn tension is recorded. Yarn processing machine, arranged for carrying out the method according to at least one of claims 1 to 4, with - At least one supply spool receptacle (24,30,41), adapted for receiving in each case at least one feed bobbin (20,29,46), of which yarns are unwindable, and a multifilament yarn production unit (5, 42) into which the yarns can be fed from the feed bobbins (20, 46) via yarn runs, each with a thread tension,
characterized in that
in at least one controlled yarn path (1.40) between the associated supply spool receptacle (24, 41) and the multifilament yarn production unit (5, 42) a yarn tension control module (25, 53) is arranged with a yarn tension sensor (54), wherein the Yarn tension control module (25,53) preferably comprises a yarn brake (55) and / or a controllable delivery mechanism (56,7), and wherein the yarn tension control module (25,53) is adapted to derive a controlled variable of a yarn tension measured by the yarn tension sensor (54) and keep the thread tension constant in a predetermined thread tension range. Yarn processing machine according to claim 5, characterized in that the multifilament yarn production unit (42) arranged in the yarn path one behind the other preferably a delivery mechanism (48), a heater (43) and a subsequently arranged cooler (44) and subsequently arranged a Lufttexturierdüse or preferably a swirl generator (45). includes. Yarn processing machine according to claim 5 and / or claim 6, characterized
marked that
the multifilament yarn production unit has an air-covering nozzle (5), wherein preferably a delivery mechanism (7) and / or at least one thread guiding device (22, 32) are provided in the yarn path (1) in front of the air-covering nozzle (5), and wherein a supply spool receptacle (24, 30) in the controlled yarn path (1) is arranged to unwind a highly elastic yarn from a supply spool (20, 29) taken up by the supply spool receptacle (24, 30).

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