Automatic piecing method for rotor spinning based on regulating length of leftover tail yarn

Abstract

The present invention designs an automatic piecing method for rotor spinning based on regulating the length of leftover tail yarn. For yarn breakage caused by a temporary stop or power outage-induced stop during rotor spinning, a backup power supply is used to supply power and operations of various components of a rotor spinning machine are controlled; and by precisely calculating the length of spinnable yarn from residual fibers in the spinning machine after passing through a rotor, mechanisms such as a drafting roller and a winding roller are guided and controlled to shut down in an orderly manner, so that a tail end of broken tail yarn stops within a yarn guide tube of a balloon limiter, thereby completing an automatic tailing function during shutdown. Then, when the machine is restarted or power is restored, a doffing mechanism is controlled to unwind the broken yarn as a seed yarn into a condensing groove in the rotor, and the seed yarn overlaps, wraps, and twists with a fiber flow formed by a cotton sliver, which is fed by a feed roller and passes through a carding roller and a fiber transport channel into the condensing groove in the rotor, to complete a piecing operation. Furthermore, parameters such as linear density, twist, and strength of a seed yarn-fiber flow twisted structure are further regulated, thereby improving the piecing success rate, achieving the high-quality automatic piecing function, and enhancing the production efficiency of an enterprise.

Description

A method for automatic splicing of rotor spinning based on adjusting the tail length of the yarn. Technical Field

[0001] This invention relates to a method for automatic splicing of rotor spinning based on adjusting the tail length of the yarn, belonging to the field of spinning automation technology. Background Technology

[0002] During rotor spinning, temporary stops or power outages can cause yarn breakage. To resume spinning, the following steps are necessary: ​​① Clean the fibers remaining in the spinneret; ② Locate the broken yarn from the bobbin, pull out a specific length of yarn, pass it through the guide roller's gripping point and into the guide twist-stop tube, where it extends to the stripping point inside the rotor under negative pressure airflow; ③ Feed the cotton sliver into the cotton roller, where the separated single fibers are fed into the rotor through the carding roller and airflow channel, coalescing to form a new fiber sliver, which intersects with the seed yarn located at the stripping point inside the rotor and wraps around it to complete the splice; ④ Start the winding mechanism to resume normal spinning. Splicing methods include manual splicing, semi-automatic splicing, and fully automatic splicing.

[0003] For temporary shutdowns and power outages, existing technical solutions have the following problems: ① The yarn tail after breakage is wound onto the yarn package, requiring re-splitting to continue spinning; ② After breakage, how to adjust the winding mechanism not only to keep the yarn tail in the yarn guide twisting tube, but also to design the tail length to ensure that the tail yarn and the newly condensed fiber sliver can overlap and intersect at the rotor peeling point to form a splice. Therefore, the efficiency of existing technologies in application is not high. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an automatic splicing method for rotor spinning based on adjusting the tail length of the yarn. The invention adopts a brand-new design and efficiently implements the designed stop tail length retention method and splicing method, effectively solving the problem of yarn breakage during stop in rotor spinning and improving splicing efficiency.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] 1. Inventing a method for retaining yarn ends during power outages in rotor spinning: In order to eliminate the need to find broken ends from the yarn cones and start new yarn in the traditional splicing process, the UPS power supply after a power outage controls the orderly stopping of each component of the rotor spinning machine, so that the broken yarn ends are retained in the yarn guide tube of the twist stopper to complete the function of retaining yarn ends. When the machine is restarted, it will serve as the tail yarn to lay the foundation for automatic splicing.

[0007] 2. Invention of a method for controlling the position of the yarn tail based on the change of the tail length: In order to accurately control the position of the yarn tail, for different rotor spinning equipment, different spinning raw materials and processes, the weight of the fibers remaining in the spinning machine after power failure and the length of the yarn that can be spun are calculated. By designing the tail length, the position of the yarn tail in the yarn guide twisting tube can be precisely controlled.

[0008] 3. Invent a method for controlling the release length of seed yarn based on the change of the storage yarn length: By controlling the reversing speed and time of the winding roller, the length of the yarn stored in the storage tube under negative pressure is controlled, and the length range of the yarn in the storage tube released as seed yarn by the yarn guiding roller at the beginning of splicing is further controlled.

[0009] 4. Invent a method for automatic splicing of seed yarn and fiber flow in the rotor: By coordinating the changes in the start-up time of the cotton roller, the release length and time of the seed yarn, and the winding time of the winding drum, the overlap length and twisting time of the seed yarn and fiber flow are controlled, and the morphological structure and mechanical properties of the seed yarn-fiber flow twisted body are further controlled to improve the quality of splicing.

[0010] The automatic splicing method for rotor spinning based on adjusting the tail yarn length described in this invention has the following technical advantages compared with the prior art:

[0011] This invention designs an automatic yarn splicing method for rotor spinning based on controlling the tail length of the yarn. Addressing the issue of yarn breakage due to temporary stops or power outages during rotor spinning, a UPS (Uninterruptible Power Supply) provides backup power to the entire machine, controlling the actions of various components. By precisely calculating the spinnable yarn length of residual fibers after passing through the rotor, a program guides the orderly shutdown of mechanisms such as the guide roller and winding roller, ensuring the broken yarn tail stops within the twist stopper's guide tube, thus achieving automatic yarn tail retention during shutdown. Then, upon restarting... When the machine is started or power is restored, the control mechanism unwinds the broken yarn as seed yarn into the rotor's condensing trough. This yarn overlaps and twists with the fiber stream formed by the cotton sliver fed into the rotor's condensing trough via the carding rollers and fiber conveying channel, completing the splicing action. Based on the tail yarn's dwell position using the automatic tail-keeping function, the overlap length and twisting time of the seed yarn and fiber stream are precisely calculated to further adjust parameters such as linear density, twist, and strength of the seed yarn-fiber stream twisted body, improving the splicing success rate and achieving high-quality automatic splicing. This enables efficient and automated completion of automatic tail-keeping and automatic splicing functions during temporary stops or power outages in rotor spinning, improving enterprise production efficiency. Attached Figure Description

[0012] Figure 1 is a flowchart of the shutdown tail retention method in the design of this invention;

[0013] Figure 2 is a schematic diagram of the fibers that remain in the rotor spinning machine after a power outage, as designed and applied in this invention.

[0014] Figure 3a is a schematic diagram of the yarn length corresponding to each position in the continuous spinning process in Figure 2;

[0015] Figure 3b is a schematic diagram showing the yarn lengths corresponding to the locations in Figure 2 after a power outage and machine shutdown.

[0016] Figure 4 is a flowchart of the joint method in the design of this invention;

[0017] Figure 5 shows the speed distribution of different yarn formation paths within the rotor spinner in the design of this invention;

[0018] Figure 6 is a schematic diagram of the force analysis of the fiber on the sliding surface inside the rotating cup in the design of this invention;

[0019] Figure 7 is a schematic diagram of the fiber loop linear density distribution in the rotor cup condensation tank;

[0020] Figure 8 shows a mass of Ω. σ A schematic diagram of fiber length distribution in a rotary cup condenser;

[0021] Figures 9 to 12 are schematic diagrams of the overlapping structures of four types of seed yarn and fiber flow;

[0022] Figure 13 is a schematic diagram of the joint structure morphology analysis corresponding to Figure 12;

[0023] Figure 14 is a schematic diagram of the mechanism of the TQFK86 rotor spinning machine.

[0024] Among them, 1. yarn bobbin, 2. winding assembly, 3. yarn storage tube, 4. yarn guide roller, 5. yarn guide motor, 6. yarn guide roller, 7. electronic yarn clearer, and 8. spinning machine. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] To address the problems of the prior art, the present invention adopts the following technical solution:

[0027] 1. Inventing a method for retaining yarn ends during power outages in rotor spinning: In order to eliminate the need to find broken ends from the yarn cones and start new yarn in the traditional splicing process, the UPS power supply after a power outage controls the orderly stopping of each component of the rotor spinning machine, so that the broken yarn ends are retained in the yarn guide tube of the twist stopper to complete the function of retaining yarn ends. When the machine is restarted, it will serve as the tail yarn to lay the foundation for automatic splicing.

[0028] 2. Invention of a method for controlling the position of the yarn tail based on the change of the tail length: In order to accurately control the position of the yarn tail, for different rotor spinning equipment, different spinning raw materials and processes, the weight of the fibers remaining in the spinning machine after power failure and the length of the yarn that can be spun are calculated. By designing the tail length, the position of the yarn tail in the yarn guide twisting tube can be precisely controlled.

[0029] 3. Invent a method for controlling the release length of seed yarn based on the change of the storage yarn length: By controlling the reversing speed and time of the winding roller, the length of the yarn stored in the storage tube under negative pressure is controlled, and the length range of the yarn in the storage tube released as seed yarn by the yarn guiding roller at the beginning of splicing is further controlled.

[0030] 4. Invent a method for automatic splicing of seed yarn and fiber flow in the rotor: By coordinating the changes in the start-up time of the cotton roller, the release length and time of the seed yarn, and the winding time of the winding drum, the overlap length and twisting time of the seed yarn and fiber flow are controlled, and the morphological structure and mechanical properties of the seed yarn-fiber flow twisted body are further controlled to improve the quality of splicing.

[0031] Specifically, the automatic splicing method for rotor spinning designed in this invention is based on the control of the tail yarn length. After the rotor spinning is powered off, the backup power supply and PLC control the operation of each mechanism of rotor spinning to achieve the automatic head-keeping function by adjusting the tail yarn length and tail yarn position. After the power is turned on and spinning is restarted, the automatic splicing function is achieved by controlling the overlap process between the new fiber ring formed in the rotor coagulation tank and the tail yarn. Furthermore, the splicing morphology and structure are optimized by controlling the overlap process.

[0032] The design of the automatic tail-keeping mechanism and automatic splicing method for rotor spinning machine power failure shutdown is as follows.

[0033] 1. Mechanism for automatic tail retention during rotor spinning machine shutdown in the event of power failure

[0034] Automatic tail-keeping is designed to prevent sudden power outages during normal operation of equipment. With the help of generators in some parts and the UPS uninterruptible power supply, the entire machine is controlled to stop in an orderly manner, and the position of the yarn tail after spinning is precisely controlled, creating favorable conditions for automatic reconnection of the equipment when power is restored.

[0035] As shown in Figure 1, after a power outage, the machine is powered by a high-inertia rotating mechanism such as a waste removal fan or by a UPS (Uninterruptible Power Supply) to maintain the tail-end function of the rotor spinning machine. After a power outage, the carding roller and rotor stop naturally due to their own inertia. Based on the UPS power supply, the feed roller, yarn guide roller, and winding roller are reduced to 30% to 60% of their operating speed. When a stop feeding command is received, the feed roller instantly reverses and breaks the sliver at the carding roller spacing point. The fibers remaining in the carding roller, airflow channel, and rotor are transformed into yarn under the action of the carding roller, airflow channel, rotor, and yarn guide roller. By appropriately controlling the tail-end length of the winding mechanism, not only can the yarn tail end be kept in the yarn guide twist-stop tube, but the position of the tail yarn in the yarn guide twist-stop tube can also be precisely controlled. Automatic tail-end management lays the foundation for automatic splicing.

[0036] 2. The design meets the requirements for the tail yarn length and dwell position of the automatic splicer.

[0037] By retaining the yarn tail formed by residual fibers in the rotor spinning process after power failure within the yarn guide twist-stop tube under the action of the winding mechanism, the action of finding the yarn end from the package yarn in the traditional splicing process can be eliminated. During splicing, the guide roller needs to release a certain length of the tail yarn to overlap and intersect with the newly condensed fiber flow in the rotor at the peeling point, and then wrap and twist it to complete the automatic splicing. Therefore, the tail yarn length and the position of its dwell are prerequisites for completing the splicing function. At the same time, after the splicing is completed, starting the winding mechanism to continuously draw the yarn out of the rotor to complete the winding is an auxiliary action that must be completed by the automatic splicing.

[0038] (1) Mechanism of tail length retention

[0039] As shown in Figure 2, after the power is cut off, the cotton feed roller instantly reverses direction and breaks the cotton sliver at the carding roller spacing point g. The tail length is the length of the yarn remaining after the fibers in the carding roller, airflow channel, and rotor are drawn out and held at a specific position by the action of the carding roller, airflow channel, rotor, and guide roller. Let L be the tail length. x (mm). The spinnable yarn length of the residual fiber is the yarn length that the fiber can be converted from the distance g of the carding roller in Figure 2 to the stripping point p inside the rotor.

[0040] Taking the yarn-drawing roller gripping point a in Figure 2 as a reference, in the continuous spinning process shown in Figure 3a, the yarn within the distance from the rotor peeling point p to the yarn-drawing roller gripping point a is normal yarn. Let this distance be L. pa Furthermore, it can be obtained according to the mechanical structure dimensions; after a power outage, as shown in Figure 3b, the yarn-drawing roller, under the action of the UPS uninterruptible power supply, twists and shapes the fibers remaining in the GP section of the spinning machine and draws them out, continuing to run for a length L. xThen stop. At this point, the yarn at point a of the yarn guide roller shown in Figure 3a has reached point q, which is L. aq The length is equal to L x Therefore, the yarn tail winding length is the calculated length L of the continuous operation of the yarn guide roller after a power outage. x This means calculating the spinnable yarn length and its dwell position of the fiber within the distance from the carding roller gap point g, through the carding roller, fiber conveying channel, rotor, to the rotor peeling point p (path gp in Figure 2).

[0041] (2) Position where the tail yarn stops

[0042] The tail yarn dwell position refers to the coordinates of the tail yarn end within the yarn guide twist-stop tube. Analysis of the overlap and convergence length of the seed yarn and the fiber flow condensed in the rotor's condensation tank at the peeling point reveals that an excessively long overlap leads to an excessively large thick section at the splice, while an excessively short overlap prevents proper splicing. Therefore, a suitable tail yarn release length is crucial for splicing success rate and quality. Precisely controlling the tail yarn's dwell position within the twist-stop tube after power failure provides an initial reference position for the yarn guide roller's release of the tail yarn during splicing, allowing for further precise control of the released tail yarn length.

[0043] As can be seen from the above (1) interruption of the tail yarn retention length mechanism, the dwell position of the tail yarn is related to the continuous running length L of the guide roller. x Related to length L x The length L is related to the weight of the fiber sliver remaining in the spinning machine after a power outage and the speed of the lead-in roller. Therefore, it is necessary to analyze the speed distribution of the fiber sliver remaining in the spinning machine at different stages after a power outage, establish a mathematical model of the speed at different stages and the speed of the lead-in roller, and then calculate the length L. x Then, by adjusting the speed of the guide roller, the precise control of the tail yarn's stopping position can be achieved.

[0044] 3. Implementation method of automatic splicing function in rotor spinning

[0045] Automatic splicing in rotor spinning is a spinning technology that utilizes the tail yarn retained in the yarn guide tube and the fiber flow re-condensed in the rotor to overlap, converge, and wrap around each other at the stripping point, completing the yarn breakage splicing and continuously drawing the yarn out of the rotor under the action of the winding mechanism.

[0046] The automatic splicing process is shown in Figure 4. After power is supplied, the rotor and carding roller start at set values. The winding roller reverses and unwinds a specific length of yarn, which is stored in the yarn storage tube under the action of negative pressure airflow. The cotton feeding roller starts at a set speed to feed in the sliver, which is separated into single fibers by the carding roller and airflow channel and enters the rotor's cohesive groove to form a fiber flow. Then, the lead yarn releases the seed yarn, which sinks into the rotor's cohesive groove under the action of negative pressure airflow and is twisted by the rotor. The continuously rotating tail yarn ends intersect and overlap with the fiber flow for a certain length and become entangled with each other, breaking the fiber flow and driving it to twist synchronously to form a seed yarn-fiber flow twisted body, completing the splicing. At this time, the winding device is started to continuously draw the yarn out of the rotor and wind it into a cone. Therefore, the key to automatic splicing is to control the overlap length between the seed yarn released by the lead yarn roller and the fiber flow in the rotor, as well as the twisting time of the seed yarn-fiber flow twisted body.

[0047] (1) Mechanism of overlap length between seed yarn and fiber flow

[0048] The overlap length between the seed yarn and the fiber flow is the length of the seed yarn released by the guide roller from the initial position (the position where the tail yarn stays after power failure), which enters the rotor cohesion tank through the rotor peeling point and overlaps with the fiber flow. Therefore, by precisely controlling the position of the tail yarn end that is automatically retained after power failure, and by controlling the reverse speed and reverse time of the guide roller, the release length of the seed yarn can be controlled, and the overlap length between the seed yarn and the fiber flow can be further adjusted.

[0049] (2) Mechanism of seed yarn-fiber flow twisting time

[0050] The twisting time of the seed yarn-fiber flow twister refers to the time from when the seed yarn stops being released by the guide roller to when the winding device starts to guide the yarn after the splicing is completed. During the twisting time, the seed yarn, which sinks into the rotor's condensing tank under the action of negative pressure airflow, breaks the fiber flow in the condensing tank and drives the fibers in the fiber flow to wrap around and twist synchronously, thus completing the splicing. Therefore, the twisting time not only affects the quality of the splice but also the time to start the winding device. The quality of the splice includes parameters such as the twist and thickness of the splice. The greater the twist, the higher the strength of the splice. However, excessive twist will cause a twisting shrinkage effect, which will affect the success rate of the splice. The thickness of the splice is positively correlated with the twisting time. The longer the twisting time, the thicker the splice. However, too short a twisting time will also affect the success rate of the splice. Therefore, the twisting time is fine-tuned within a certain range according to the quality of the splice. After the twisting time is determined, the timing can be started from when the seed yarn stops being released by the guide roller. When the twisting time is reached, the winding device is started to guide the yarn.

[0051] Based on the above mechanism construction and analysis, the automatic splicing method for rotor spinning designed in this invention based on adjusting the tail length of the tail yarn is designed for rotor spinning machines with backup power supply. In practical applications, the design includes a shutdown tail-leaving method triggered by power failure, which executes the following steps A to B, and a splicing method triggered by power restoration, which executes the following steps I to III.

[0052] Step A. The carding roller and rotor stop naturally due to their own inertia. At the same time, the components of the rotor spinning machine are stopped in an orderly manner based on backup power such as UPS uninterruptible power supply. Specifically, power is supplied to the cotton roller, yarn guide roller and winding roller, and the cotton roller, yarn guide roller and winding roller are controlled to decelerate to 30% to 60% of their original working speed and continue to work. Then proceed to step B.

[0053] The above mechanism analysis shows that in the rotor spinning continuous spinning process, the fiber velocity distribution varies at different stages due to the different yarn formation paths. Let the velocities at each stage be: feed roller linear velocity V1 (m / min), fiber conveying channel inlet velocity V2 (m / min), fiber conveying channel outlet velocity V3 (m / min), condensing trough linear velocity V4 (m / min), and guide roller linear velocity V… y (m / min), the speed of the combing roller is n f (rpm), the rotor speed is n z (rpm) can be divided into several stages as shown in Figure 5.

[0054] (1) After power failure, in the cotton feeding area, the fibers within the cotton feeding-carding gripping gap are transferred to the fibers of the carding roller;

[0055] (2) In the combing zone, starting from the point where the combing roller holds the gap, the combing roller needle separates the cotton sliver from the cotton roller into single fibers and sends them into the fiber conveying channel.

[0056] (3) In the fiber conveying channel, the single fiber flow is conveyed to the inner wall of the rotor under the negative pressure formed by the speed of the combing roller and the speed of the rotor;

[0057] (4) In the rotor, the single fiber captured in the rotor sliding surface is gradually accelerated to the rotor speed by the high speed of the rotor and gradually condensed in the coagulation tank along the sliding surface from the rotor position corresponding to the fiber conveying channel. When the fiber gradually stacked at the peeling point of the coagulation tank reaches the set yarn weight, it is twisted by the yarn drawing roller and drawn out through the yarn drawing twist resistance tube.

[0058] Therefore, by analyzing the speed distribution of the fiber sliver in the above four stages, the quantitative relationship between the weight of the fiber sliver and the speed of the yarn drawing roller is established, and the tail length of the yarn is calculated, that is, further performing the following step B.

[0059] Step B. Send a stop feeding command to the feed roller, controlling the feed roller to instantly reverse and stop. At the carding roller spacing point, the sliver conveyed by the feed roller will be broken. Under the operation of the guide roller and winding roller, the fibers remaining in the carding roller, fiber conveying channel, and rotor will be transformed into yarn under the action of the carding roller, fiber conveying channel, rotor, guide roller, and winding roller. At the same time, control the guide roller and winding roller to wind the yarn onto the winding mechanism, stopping the yarn tail in the guide twist-stop tube. This can eliminate the need to find the yarn end from the bobbin in the traditional splicing process and control the guide roller and winding roller to stop.

[0060] In practical applications, the fibers remaining in the carding roller, fiber conveying channel, and rotor, including the residual fibers from the instantaneous reverse output of the cotton feeding roller, the residual fibers in the carding roller, the residual fibers in the fiber conveying channel, the residual fibers on the sliding surface of the rotor, and the residual fiber rings in the coagulation groove of the rotor, are calculated and their corresponding weights are obtained as follows.

[0061] The weight Ω1 of the residual fibers output during the instantaneous reverse rotation of the cotton roller is obtained as follows:

[0062] Based on the length L of the fiber held between the gripping point of the cotton feeding roller and the spacing point of the combing roller. 12 According to the following formula:

[0063] Ω 12 =L 12 ×ρ s (1)

[0064] The weight Ω of the held fiber is obtained. 12 , where ρ s This indicates the fixed weight of the cotton swabs fed into the cotton roller.

[0065] After power failure, the feed roller decelerates to 50% of its set speed, then momentarily reverses to retract the sliver, causing it to break at the carding roller spacing point. Due to inertia, the carding roller continues to rotate, feeding the fibers gripped by the carding roller needles into the airflow channel, where they then enter the rotor under the influence of the airflow. Because the feed roller grips the sliver through a tight grip between the roller and the feed plate, while the carding roller grips the sliver through a carding grip between the carding needles and the feed plate, and because the main body length of the fiber is greater than the feed-carding grip spacing L... 12 Therefore, the breakage and separation of the sliver is based on the spacing point of the combing rollers. One can imagine the weight Ω of the fiber flow held in the feeding and combing sections. 12 In the process, besides the weight of the fiber flow brought back by the reverse rotation of the feed roller, the weight of the fiber flow transferred to the carding roller is Ω1. The fiber transfer rate k from the feed roller to the carding roller when the power is off is defined as follows:

[0066] k = Ω1 / Ω12 (2)

[0067] Therefore, the fiber transfer rate k of the subsequent instantaneous reverse rotation of the cotton feeding roller to the carding roller is calculated using the following formula:

[0068] Ω1=Ω 12 ×k(4)

[0069] The weight Ω1 is obtained.

[0070] In applications, the fiber transfer rate (k) has a significant impact on the length of the yarn tail. The k value is typically related to factors such as the main fiber length and its distribution, fiber fineness and its distribution, sliver weight, short fiber percentage, and impurity content. Based on experiments and relevant experience, the general range of k values ​​is as follows:

[0071] -1%≤k≤1%(3)

[0072] ① If the k value is too large, a longer tail yarn length can be obtained. When it is used as the seed yarn and the fiber flow output from the rotor coagulation tank, the excessively long tail yarn will stay in the rotor, causing blockage of the coagulation tank channel and preventing normal connection.

[0073] ② If the value of k is within a reasonable range, a reasonable tail yarn length can be obtained. When it is used as the connector between the seed yarn and the fiber flow output from the rotor condenser, the tail yarn will stay at the peeling point inside the rotor and can form a normal connector with the fiber flow output from the rotor condenser.

[0074] ③ If the k value is too small, the tail yarn length will be too short. As the seed yarn, the tail yarn will not stay at the stripping point inside the rotor and will not be able to form a normal joint with the fiber flow output from the rotor cohesion tank.

[0075] Since the entire spinning process is continuous, after the equipment is powered off, the fiber weight from the carding roller gripping point (distance point) to the fiber feed channel inlet remains consistent with the fiber weight during the continuous spinning process, that is, the amount fed in is equal to the amount output. Therefore, the weight Ω2 of the residual fiber in the carding roller is obtained as follows:

[0076] According to the following formula:

[0077]

[0078] Obtain the arc length L of the combing roller f The corresponding time t1, where L f n represents the arc length of the combing roller from the point where the combing roller is positioned to the fiber conveying channel. f D represents the rotational speed of the combing rollers. f This indicates the diameter of the combing roller.

[0079] Then follow the formula below:

[0080] Ω2=t1×V y ×ρ y (6)

[0081] Obtain weight Ω2, where V y ρ represents the linear velocity of the yarn drawing roller. y This indicates the linear density of the yarn.

[0082] Since the entire spinning process is continuous, after the equipment is powered off, the weight of the fiber flow in the fiber conveying channel remains consistent with the fiber weight during the continuous spinning process, that is, the amount fed in is equal to the amount output. Therefore, the weight Ω3 of the residual fiber in the fiber conveying channel is obtained as follows:

[0083] First, follow the formula below:

[0084] V2 = V f =η2×n f ×π×D f (7)

[0085] The linear velocity V2 at the fiber conveying channel inlet is obtained, where η2 represents the correction coefficient for converting the combing roller linear velocity into fiber transfer velocity, and n f D represents the rotational speed of the combing rollers. f V represents the diameter of the combing roller. f This indicates the linear speed of the combing roller.

[0086] Simultaneously, use the following formula:

[0087] V3=η3×π×n z ×D Z1 (8)

[0088] The linear velocity V3 at the fiber conveying channel outlet is obtained, where η3 represents the correction coefficient for converting the rotor linear velocity into fiber transfer velocity, and n z D represents the rotational speed of the rotor. Z1 This represents the diameter of the corresponding circle on the sliding surface of the rotor.

[0089] Then follow the formula below:

[0090]

[0091] The fiber flow transfer time t2 within the fiber transport channel is obtained, where L2 represents the length of the fiber transport channel.

[0092] Finally, use the following formula:

[0093] Ω3=t2×V y ×ρ y (10)

[0094] Obtain weight Ω3, where V yρ represents the linear velocity of the yarn drawing roller. y This indicates the linear density of the yarn.

[0095] Regarding the fiber weight within the rotor, the fibers that initially enter the rotor from the fiber feed channel are gradually accelerated to the rotor's rotational speed by the high-speed rotation of the rotor. During this acceleration, the fibers gradually condense along the sliding surface from the rotor position corresponding to the fiber feed channel outlet into the condensation tank. Therefore, the fiber volume within the rotor should be divided into two parts: the first part is the fiber weight from its initial entry into the rotor from the fiber feed channel outlet to the condensation tank position, and the second part is the fiber weight within the condensation tank.

[0096] Regarding the residual fibers on the sliding surface of the rotor, the process of the fibers gradually entering the rotor coagulation tank from the fiber conveying channel outlet along the sliding surface is an accelerated process. Assuming the linear velocity of the coagulation tank is V4, during the entire spinning process, the continuous fibers are separated into single fibers after passing through the combing roller and uniformly reach the rotor sliding surface through the fiber conveying channel. Then, they form continuous fiber rings layer by layer in the coagulation tank, and the sliver is drawn out and twisted into yarn near the peeling point.

[0097] As shown in Figure 6, the single fiber entering the rotor from the fiber feeding channel outlet can be considered as a particle M with a certain weight m. According to the literature, the centrifugal force on the fiber particle is much greater than its own weight. Moreover, the relative velocity between the fiber particle and the air is very small, so its own weight and air resistance can be ignored.

[0098] Therefore, the weight Ω4 of the residual fibers on the sliding surface in the rotor cup is obtained as follows:

[0099] First, based on the rotor radius r and angular velocity ω corresponding to the point on the rotor's sliding surface when the fiber is transferred, and taking the fiber at that point as the fiber particle, we obtain the centrifugal force F1 acting on the fiber particle, the component of the fiber particle along the rotor wall towards the condensation tank F2, the component of the fiber particle perpendicular to the rotor wall F3, the acceleration a of the fiber particle along the rotor's sliding surface, the mass m of the fiber particle, the coefficient of friction μ between the fiber and the rotor wall, and the rotor's inner wall inclination angle γ. The dynamic equations are then constructed as follows:

[0100]

[0101] Next, let t3 be the time it takes for the fiber to transfer from the fiber conveying channel outlet to a certain position on the inner sliding surface of the rotor. Then, based on the length x that the fiber slides along the generatrix of the rotor sliding surface during this time, and differentiating the acceleration a in equation (11), we obtain the following:

[0102]

[0103] Then, based on the entire sliding process of the fiber transferring from the fiber conveying channel outlet to the rotor condenser, x and r in equation (12) have a linear increasing relationship, and the following structure is constructed:

[0104]

[0105] Among them, L h D represents the distance along the rotor's generatrix from the fiber conveying channel outlet to the position of the internal coagulation tank. Z This represents the diameter of the condensation tank.

[0106] Combining equations (11), (12), and (13), when the fiber slides from the fiber conveying channel outlet into the coagulation tank inside the rotor, i.e., x = L h The time t3 for the fiber to slide from the fiber conveying channel outlet to the condensation tank can be obtained by the characteristic root method, and then it can be calculated according to the following formula (14):

[0107]

[0108] The time t3 is calculated for the fiber to slide from the fiber conveying channel outlet to the coagulation tank inside the rotor.

[0109] Finally, use the following formula:

[0110] Ω4=t3×V y ×ρ y (15)

[0111] Obtain weight Ω4, where V y This indicates the linear speed of the yarn drawing roller.

[0112] Regarding the weight of the residual fiber rings in the coagulation tank of the rotor, when the rotor rotates at high speed, it can be assumed that the distribution of single fibers continuously input into the rotor coagulation tank through the fiber feeding channel and sliding surface within a very short time on the circumference of the rotor coagulation tank is equally probable. That is to say, the distribution length of the single fibers continuously input within the rotor coagulation tank within a very short time is the circumference of the rotor.

[0113] Taking the stripping point as the research object, the fiber at the stripping point moves relative to the rotor at a speed equal to the extraction speed within the rotor. Let point O be any point within the rotor's condensation tank, and let the stripping point start from point O, move around the circumference of the rotor's condensation tank once, and then return to point O. During this period (rotor rotation cycle), the number of times the stripping point passes the fiber delivery channel outlet (the number of rotations of the rotor within one revolution of the stripping point within the rotor) is y, which is the number of single fibers coalescing in the condensation tank.

[0114] Let t4 be the time it takes for the rotating cup to complete one revolution. Then:

[0115]

[0116] Since the entire spinning process is continuous, the fiber feed and output remain balanced per unit time to ensure a stable yarn count. Therefore, based on the fiber merging effect in the condensing tank described above, and taking the stripping point as the research object, the linear density of the fiber rings in the rotor condensing tank can be considered as linearly distributed, as shown in Figure 7. Let the stripping point be O1 at the beginning of one rotor rotation cycle and O2 at the end. That is, starting from the stripping point, the linear density of the fiber rings in the condensing tank linearly decreases from high along the direction of movement of the stripping point until it is zero at the position where the yarn is just pulled out from the stripping point by the drawing roller.

[0117] The weight Ω5 of the residual fiber ring in the coagulation tank of the rotating cup is determined by the following formula:

[0118]

[0119] Obtain weight Ω5, where ρ y D represents the linear density of the yarn. Z This indicates the diameter of the condensation tank in the rotating cup.

[0120] Based on the weight analysis of the residual fibers obtained above, the length L of the yarn corresponding to the residual fibers transformed into yarn under the action of the combing roller, fiber conveying channel, rotor, yarn guide roller, and winding roller is further analyzed. Ω Obtain as follows, then based on the length L of the yarn converted. Ω Control the operation of the yarn guide roller and the winding roller, stop the end of the yarn in the yarn guide twist tube, and finally control the yarn guide roller and the winding roller to stop rotating.

[0121] First, based on the weight Ω1 of the sliver fibers transferred away by the combing roller when the feed roller instantly reverses, the weight Ω2 of the residual fibers in the combing roller, the weight Ω3 of the residual fibers in the fiber conveying channel, the weight Ω4 of the residual fibers on the sliding surface in the rotor, and the weight Ω5 of the residual fiber rings in the coagulation trough in the rotor, the following formula is used:

[0122] Ω=Ω1+Ω2+Ω3+Ω4+Ω5(18)

[0123] Obtain the sum of the weights Ω, then use the following formula:

[0124]

[0125] Obtain the total residual fiber weight Ω corresponding to the number i of fiber rings in the rotor condensation tank, and the remaining residual fiber weight Ω that is less than one complete fiber ring. σ .

[0126] Ω σLet L be the mass of the fiber sliver remaining after a fiber stream of weight Ω forms i fiber rings in the rotor coagulation tank. Therefore, the total length L of the spinnable yarn from the remaining fiber weight Ω after power is cut off. Ω Including the length L of i fiber rings formed within the rotating cup condenser τ And the remaining weight is Ω σ The fibers gradually overlap in the cohesion tank according to the merging effect to form a yarn tail section L that is from coarse to fine. σ Then L σ The length is shown in Figure 8.

[0127] According to the following formula:

[0128]

[0129] For weight Ω σ The remaining residual fibers gradually accumulate in the coagulation tank of the rotor cup due to the rotor cup merging effect, forming fiber rings that gradually become thinner, according to the following formula:

[0130] L σ =(Ω) σ ×2) / ρ y (twenty one)

[0131] Obtain the length L corresponding to the yarn tail. σ , where ρ y This indicates the linear density of the yarn.

[0132] Finally, according to the following formula:

[0133] L Ω =L σ +L τ =(Ω) σ ×2) / ρ y +i×π×D Z (twenty two)

[0134] Obtain length L Ω , where D Z L represents the diameter of the condensation tank in the rotating cup. τ This indicates the length of the yarn corresponding to all remaining fibers.

[0135] Regarding the calculation of the tail length and stopping position after power failure, the tail length L after power failure is... x This refers to the start of the yarn feeding roller at a set speed V, beginning when the feed roller stops feeding cotton. y Running for a specific time t x The length of the yarn that is drawn out is then stopped. Therefore, the key to calculating the tail length is to ensure that all the spinnable yarn length of the residual fiber in the spinning machine is drawn out, and that the end of the drawn-out tail yarn is kept in the yarn guide twist tube to prepare for automatic splicing.

[0136] Given that the length of spinnable yarn remaining in the spinning machine after a power outage is L Ω Taking the peeling point inside the rotor as a reference, if the tail length is less than L Ω If the tail yarn ends before the rotor's separation point, it will break off and be carried away by the negative pressure airflow as the rotor rotates. Therefore, the tail yarn length should be greater than L. Ω Furthermore, it should not exceed the center position of the yarn guide tube. Since the tail end of the yarn is not held, if it exceeds the center position of the yarn guide tube, it may be affected by airflow disturbances in the workshop, causing the tail end to exit the yarn guide tube. Therefore, a safe tail length range should ensure that the tail end enters the yarn guide tube and does not exceed the center position. Let L be the distance from the bottom of the yarn guide tube to the rotor peeling point. B The length of the yarn guide twist-stop tube is L zg Then, based on the length L of the yarn transformed from the residual fibers... Ω According to the following formula:

[0137]

[0138] Determine the control of the lead-in roller and winding roller lead-out length L. x The yarn is wound onto the winding mechanism, and the yarn end is stopped inside the yarn guide tube, where t x This indicates the length L corresponding to the drawing roller and the winding roller, respectively. x Yarn running time, V y This indicates the length L corresponding to the drawing roller and the winding roller, respectively. x Yarn linear velocity, L B L represents the length from the bottom of the yarn guide twist-stop tube to the peeling point inside the rotor. zg This indicates the length of the yarn guide twist-stop tube.

[0139] Step C. Control the rotor and combing roller to start working, and control the winding roller to reverse. The unwound yarn is stored in the yarn storage tube as seed yarn under the action of negative pressure airflow. Then control the winding roller to stop and proceed to step D.

[0140] Step D. Control the start of the cotton feeding roller to feed cotton sliver. The cotton sliver is separated into fibers by the combing roller and fiber conveying channel, and then conveyed to the coagulation tank in the rotor to coagulate and form a fiber stream. Then proceed to step E.

[0141] Step E. Control the yarn guide roller to reverse, release the seed yarn in the yarn storage tube and sink it into the coagulation tank in the rotor under the action of negative pressure airflow. It overlaps with the fiber flow in the coagulation tank, twists and wraps with each other to achieve splicing, and continues to spin the rotor to generate yarn. Then control the yarn guide roller and winding roller to rotate forward, continuously output the generated yarn and wind it into a cone.

[0142] Analysis of the overlap between seed yarn and fiber flow

[0143] Based on the implementation method of the automatic splicing function in rotor spinning, the key to the automatic splicing of the seed yarn and the fiber flow in the rotor is the overlap length of the seed yarn and the fiber flow, as well as the twisting time of the seed yarn and fiber flow. Taking the circumference of a rotor coagulation tank as the research object and the stripping point of the rotor coagulation tank as the reference, when the winding device starts to guide the yarn, the overlap of the seed yarn and the fiber flow in the coagulation tank can be divided into four types.

[0144] (1) As shown in Figure 9, if the seed yarn released by the yarn guide roller is reversed and has not yet overlapped with the fiber flow condensed in the rotor, the winding device will start the yarn guide and the splicing cannot be completed.

[0145] (2) As shown in Figure 10, the seed yarn released by the reverse rotation of the yarn guide roller overlaps with the fiber flow condensed in the rotor cup by a short length. The winding device starts to guide the yarn. At this time, there will be a small detail at the joint. However, the twisting time is too short, resulting in insufficient joint strength, affecting the joint quality and low success rate.

[0146] (3) As shown in Figure 11, the overlap length between the seed yarn released by the reverse rotation of the yarn guide roller and the fiber flow condensed in the rotor is the circumference of one rotor condensation groove. This length is ideal, and there will be a thick section at the joint. However, the twisting time may not meet the joint strength requirements, thus affecting the joint success rate.

[0147] (4) As shown in Figure 12, the seed yarn released by the reverse rotation of the yarn guide roller overlaps with the fiber flow condensed in the rotor, and the maximum overlap length is the circumference of one rotor condensation groove. At this time, the fiber flow condensed in the rotor condensation groove forms a stable fiber ring, and two thick nodes and one thin node appear at the joint. The strength at the joint is also reliable. Therefore, by using this joint model and adjusting the shape and structure of the joint within the allowable range of joint strength, joint quality that meets industrial requirements can be obtained.

[0148] In practical applications, the fourth seed yarn-fiber flow splicing model is selected as the method for achieving automatic splicing. The specific automatic splicing action is as follows:

[0149] First, the cotton roller is started to feed in the cotton sliver. The single fibers separated by the combing roller and airflow channel are sent into the rotor and gradually stacked in the condensing groove to form fiber rings. Then, the yarn guide roller reverses to release the seed yarn. The yarn tail left in the yarn guide twist stop is pushed past the rotor peeling point and into the rotor condensing groove under the action of negative pressure airflow. After it intersects and overlaps with the fiber rings in the condensing groove for a certain length, the yarn guide roller stops. As the rotor rotates, the seed yarn and the fiber rings wrap around each other and twist to form a twisted body. When the twisting time is reached, the winding device starts to start the yarn guide.

[0150] Regarding the joint method triggered by restoring power in steps C to E above, in actual application, in step E, the yarn guide roller is reversed, and the seed yarn in the yarn storage tube is released and sinks into the coagulation tank in the rotor under the action of negative pressure airflow. The design makes the seed yarn overlap with the fiber flow in the coagulation tank, and the upper limit of the overlap length is the circumference of one rotor coagulation tank. In the overlapping state, the fiber flow condensed in the rotor coagulation tank forms a fiber ring.

[0151] Based on the above-designed overlapping structure between the seed yarn and the fiber flow, before steps C to E of the splicing method are executed, the various control parameters are adjusted in the following manner.

[0152] The yarn storage length after power is restored refers to the length of yarn retained in the yarn storage tube after the winding roller reverses and unwinds. After power is restored, first press the process negative pressure button. When the process and impurity removal negative pressure reach the set value, the yarn storage tube air supply damper opens to maintain a certain negative pressure in the yarn storage tube. Then, the winding roller operates at the set speed V. j Reverse time t j After stopping, the unwound yarn is retained in the yarn storage tube under the action of negative pressure airflow, completing the splicing preparation action; when the yarn guide roller reverse signal is received, the yarn guide roller moves at the set speed V y1 The process involves reversing the flow of yarn, pulling out the yarn stored in the yarn storage tube as seed yarn, and releasing it to a specific position in the rotor coagulation tank. This ensures that the seed yarn and the fiber flow maintain sufficient overlap to guarantee the quality of the splice.

[0153] For the winding roller at speed V j Reverse time t j The unwinding length of L on the winding mechanism C The yarn is stored in a yarn storage tube as seed yarn under the action of negative pressure airflow, and the following model is constructed:

[0154]

[0155] Among them, L ζ This indicates the length of the seed yarn released from the yarn storage tube when the yarn guide roller reverses in step E. a1 and a2 represent L respectively. C Compared to L ζ The preset lower limit length and preset upper limit length for upward floating are, in specific applications, such as a1 = 20mm and a2 = 50mm.

[0156] Based on the definition in step E, the yarn-drawing roller is controlled at a speed of V. y1 Reverse time t7 to construct the overlap length between the seed yarn in the yarn storage tube and the fiber flow in the coagulation tank. The length L of the seed yarn released from the yarn storage tube by the yarn guide roller ζ The relationship between them is as follows:

[0157]

[0158] Among them, L B L represents the length from the bottom of the yarn guide twist-stop tube to the peeling point inside the rotor. zg t7 indicates the length of the yarn guide twisting tube, and t7 indicates the time elapsed from the start of the yarn guide roller reversing to release the seed yarn to the stop time.

[0159] Regarding the control of the twisting time between the seed yarn and the fiber flow, a longer twisting time results in a greater twist of the twisted body and a higher joint strength. However, due to the existence of a critical twist value, excessive twist can lead to over-twisted sections, causing twist shrinkage and making it difficult for the seed yarn and fiber flow to overlap. This results in a weak overlap of the twisted section, affecting the joint diameter, joint strength, and joint success rate. Therefore, while ensuring the joint success rate, the joint twist should be kept as close as possible to the critical twist value to maximize the joint strength.

[0160] Based on yarn linear density ρ y Twist coefficient α t Then the critical twist And according to the rotor speed n z Yarn drawing speed V y Then the initial twist T0 = n z / V y Further based on the overlap length With twisting time t8 and splice twist T1, based on the instantaneous twist theory of the inner yarn arm of the spinning cup, the following structure is constructed:

[0161]

[0162] The control of the seed yarn-fiber flow twisting time t8 is based on the twist coefficient α. t and critical twist For reference, by controlling the overlap length This is achieved, where different yarn types correspond to different applicable twist coefficients, which can be obtained by consulting the yarn types and twist coefficients in "Spinning Science".

[0163] According to the method of stopping the machine and leaving the tail, the working lead-out length L of the yarn-drawing roller and the winding roller is adjusted. x The yarn is wound onto the winding mechanism, the position of the yarn tail end within the yarn guide tube is determined, and the overlap length is considered. According to formula (25), the length L of the seed yarn released from the yarn storage tube by the yarn guide roller is determined. ζ The control is further adjusted according to formula (24), which controls the length L of the unwound yarn on the winding mechanism of the winding roller. C Adjustments are made based on the overlap length. The twisting time t8 is controlled by formula (26), thereby determining the various control parameters in steps C to E of the jointing method.

[0164] In practical applications, steps C to E of the joint method are executed according to the above control parameters to achieve the joint. Furthermore, during the execution of steps C to E of the joint method, a method for adjusting the joint morphology and structure based on the joint linear density and annual distribution is designed as follows: steps F to G.

[0165] Step F. First, perform the joint line density distribution analysis as follows.

[0166] The joint consists of three parts: the fiber ring superimposed on the rotor cohesive trough from the start of feeding the sliver into the cotton roller until the start of the winding device to guide the yarn; the seed yarn entering the rotor cohesive trough within the release delay t7; and the newly fed fiber flow into the rotor cohesive trough when the yarn is started to be guided.

[0167] The weight of the fiber ring is determined by the following three time periods from the start of feeding the sliver into the cotton roller to the start of the winding device: the yarn sinking delay t6, the release delay t7, and the twisting delay t8.

[0168] The yarn delay time t6 refers to the time from when the cotton sliver is fed into the cotton roller to when the yarn guide roller begins to reverse and release the seed yarn;

[0169] Release delay t7 refers to the time from the start of the yarn feeding roller reversing to release the seed yarn until it stops;

[0170] Twisting delay t8 refers to the twisting time after the seed yarn and fiber ring overlap to form a twisted body, that is, the time from when the seed yarn is released from the drawing roller to when the winding device starts drawing the yarn.

[0171] Based on the feeding speed V1 of the tampons into the cotton roller and the fixed weight ρ of the tampons... s The weight Ω6 of the fiber ring is obtained as follows;

[0172] Ω6=(t6+t7+t8)×V1×ρ s (27).

[0173] Regarding the weight of the seed yarn entering the rotor condenser within the release delay t7, it is based on the total remaining fibers, including those of length L. τ The yarn and its length are L σ The yarn tail, according to the corresponding weight Ω σ ρ, the density of the yarn y Combined with the overlap length L of the seed yarn and fiber flow ζ As follows:

[0174]

[0175] The weight Ω7 of the seed yarn that enters the rotor coagulation tank within the release delay t7 is obtained.

[0176] Regarding the weight of the newly fed fiber stream in the rotor cohesive trough at the start of yarn feeding, based on the fiber merging effect in the rotor cohesive trough, it is calculated using the following formula:

[0177]

[0178] The weight Ω8 of the newly fed fiber stream in the rotor coagulation tank at the start of yarn feeding is obtained.

[0179] Then follow the formula below:

[0180]

[0181] The total weight of the fibers at the joint is Ω. w .

[0182] Step G. Adjustment of joint morphology and structure.

[0183] The morphology of the splice is determined by the weight distribution of the three fiber components within the condensing tank. Since the fiber with a weight of Ω6 is distributed in the condensing tank as a fiber ring, its weight is evenly distributed around the circumference of the condensing tank. Based on the fiber merging effect in the rotor condensing tank, the distribution of the newly fed fiber stream with a weight of Ω8 around the circumference of the condensing tank is linear, with a minimum linear density of zero and a maximum linear density equal to the set yarn linear density. Therefore, the splice morphology is determined by the overlap length of the seed yarn. Let the linear density of the fiber ring be ρ. r =Ω6 / (π×D) Z The maximum linear density of the newly fed fiber stream is the set yarn linear density ρ. y Considering the yarn evenness, excessive or abrupt changes in linear density at the joint should be avoided. Generally, a joint structure with an overlap length equal to the length of the tail yarn transition section is selected, as shown in Figure 13.

[0184] Given that fibers with a weight of Ω6 are distributed in the form of fiber rings around the rotor condenser, and considering the fiber coalescence effect in the rotor condenser, the distribution of newly fed fibers with a weight of Ω8 around the condenser is linear. Therefore, the linear density of the fiber rings is ρ. r =Ω6 / (π×D) Z The maximum linear density of the newly fed fiber stream is set to ρ. y and combined with a length of L σ The maximum linear density of the yarn tail is set to ρ. y That is, the maximum linear density of the seed yarn in the rotor condenser is ρ yTaking the debonding point inside the rotor as a reference, within the circumference of a coagulation tank, the morphological structure changes from left to right at the joint as follows: coarse section 1 → fine section → coarse section 2. Let the linear densities of coarse section 1, fine section, and coarse section 2 be ρ1, ρ2, and ρ3, respectively, then the structure is as follows:

[0185]

[0186] Then, based on the overlap length According to formula (26), the twisting time t8 is adjusted to control the twist of the joint T1. Combined with the sand settling delay t6 and the release delay t7, the maximum and minimum linear density of the joint are controlled to achieve the regulation of the joint shape and structure.

[0187] Applying the above design scheme to practice, taking the TQFK86 rotor spinning machine in Figure 14 as an example, we use the spinning process in Table 1 to spin normally, and take 20 sets of yarn tails by manually stopping the machine.

[0188] Table 1

[0189]

[0190] The specific operation for manual shutdown is as follows: use the spinning process in Table 1 for normal spinning, and set the tail length L after power failure. x =180mm. After the spinning stabilizes, manually press the stop button. The guide roller moves 180mm and then the entire machine stops completely. At this time, the guide roller draws out all the fiber slivers remaining in the spinning unit into yarn. Taking the guide roller grip point a as a reference, measure 180mm upwards from the guide roller grip point a and cut it. This will give you the length L of the fiber sliver drawn out by the guide roller from the feed roller grip point g to the rotor peeling point p after pressing the stop button. Ωs The length L of the yarn within the distance from the rotor peeling point p to the yarn guide roller gripping point a. pa The length L of the tail yarn after power failure, consisting of two parts pq The distance from the rotor peeling point p to the yarn-feeding roller gripping point a can be measured using the mechanical mechanism of the spinning machine, and the length L of the yarn tail can also be determined. pq It can also be measured, then:

[0191] L Ωs =L pq -L pa (32)

[0192] The mass and length of each of the 20 yarn groups were measured, and then the length L of the formed yarn from the gripping point of the lead-in roller to the stripping point was subtracted from each yarn group. pa and its corresponding mass Ω pa The length L of the formed yarn from the gripping point of the yarn guide roller to the peeling point. paIf it is 187.343mm, then Ω pa =L pa ×ρ y ×10 -6 =187.343 × 37.6 × 10 -6 =0.007g. The average length and mass of the 20 sets of experimental data are shown in Table 2.

[0193] Table 2

[0194]

[0195]

[0196] Taking the TQFK86 rotor spinning machine in Figure 14 as an example, the structural parameters of the TQFK86 rotor spinning machine are shown in Table 3. It is known that after the equipment is powered off, the speed of the yarn guide roller is reduced to 50% of the normal spinning speed, which is V. y =33.33m / min. The relevant structural parameters in Table 3 can be obtained by measurement. Combined with the mathematical model of the residual fiber weight of the rotor spinner after power failure, the fiber weights of Ω1, Ω2, Ω3, Ω4, and Ω5 can be calculated. Therefore, the total residual fiber weight Ω after power failure can be obtained.

[0197] Table 3

[0198]

[0199] (1) After the power outage, the fiber weight from the break point of the sliver to the holding point of the combing roller is calculated based on the shortest remaining yarn length, i.e., k is taken as 0.01:

[0200] Ω1=k×L 12 ×ρ s = 0.01 × 18.274 × 45 × 10 -4 =0.0008223g (33)

[0201] Where: ρ s For tampon quantification, take 45g / 10m; L 12 The cotton-combing gripping distance is 18.274 mm, as shown in Table 2.

[0202] (2) The fiber weight from the gripping point of the combing roller to the inlet of the fiber conveying channel is Ω2:

[0203]

[0204] Where: L g The arc length (mm) of the combing roller from the gripping point of the combing roller to the fiber feed channel inlet is 102.638 mm, as shown in Table 2; the yarn guide roller speed V during tail retention is...y (m / min) is 50% of the set value, i.e., 33.33 m / min; ρ y For yarn linear density (tex), take 37.6 tex; n g The speed of the combing roller (rpm) is set to 8000 rpm; D g The diameter of the combing roller (mm) is 65mm, as shown in Table 2.

[0205] (3) The weight of the fiber in the fiber transport channel is Ω3:

[0206]

[0207] Wherein: the correction coefficient η2 for converting the combing roller linear velocity into fiber transfer velocity and the correction coefficient η3 for converting the rotor linear velocity into fiber transfer velocity are both taken as 1; L s The fiber feeding channel length, as shown in Table 2, is 22.811 mm; the yarn guide roller speed V during tail retention is... y (m / min) is 50% of the set value, i.e., 33.33 m / min; ρ y For yarn linear density (tex), take 37.6 tex; n z Rotor speed (rpm), set to 50000 rpm; n f The speed of the combing roller (rpm) is set to 8000 rpm; R Z1 The rotor radius corresponding to the fiber feed channel outlet is 14.05 mm, as shown in Table 2; R f The radius of the combing roller is 32.5 mm, as shown in Table 2.

[0208] (4) The weight of the fiber in the sliding surface of the rotor is Ω4:

[0209]

[0210] Where: D Z The diameter of the rotating cup condenser is 36 mm, as shown in Table 2; L h The distance from the fiber conveying channel outlet to the condensing tank along the rotor generatrix is ​​8.717 mm, as shown in Table 2; the yarn guide roller speed V during tail retention is... y (m / min) is 50% of the set value, i.e., 33.33 m / min; ρ y The yarn linear density (tex) is taken as 37.6 tex; γ is the tilt angle of the rotor sliding surface, which is 22° as shown in Table 2; ω is the angular velocity of the rotor, which can be obtained from the rotor speed as ω = 2πn z =2×3.14×50000 / 60=5233rad / s; μ is the coefficient of friction between the fiber and the cup wall, which is 0.35 as shown in Table 2.

[0211] (5) The weight of the fiber in the rotating cup coagulation tank is Ω5:

[0212]

[0213] Where: D Z The diameter of the rotating cup condenser is 36 mm, as shown in Table 1; ρ y The yarn linear density (tex) is taken as 37.6 tex.

[0214] (6) Total weight of residual fibers and length of spinnable yarn:

[0215] By analyzing the fiber transfer (velocity distribution) model for each stage mentioned above, five fiber weights can be obtained, namely Ω1, Ω2, Ω3, Ω4, and Ω5. Let Ω be the total weight of all fibers in the spinning machine after a power outage and shutdown. Then:

[0216] Ω=Ω1+Ω2+Ω3+Ω4+Ω5=0.0008223+0.0000788+0.000019+0.0000027+ 0.002125=0.0030478g(38)

[0217] According to equation (19), given the total weight Ω and Ω5 of the residual fibers after the equipment is powered off, the following can be calculated: i =1, Ω σ =0.0009228g.

[0218] According to equation (22), the total length of the remaining fiber that can be spun into yarn after the power is cut off can be calculated as L. Ω :

[0219]

[0220] (7) Length and position of the tail yarn:

[0221] L obtained through the above calculation Ω The total length L of the residual fiber that can be spun into yarn after power failure obtained in Table 2. Ωs The average difference is 0.732 mm, which is negligible. Combining Figure 3(b) and the model of the yarn tail length and position after power failure, it can be seen that to accurately control the yarn tail to remain between the bottom and middle of the yarn guide tube after power failure, according to equation (23), the tail length L... x for:

[0222]

[0223] Where L B The distance from the bottom of the yarn guide twist-stop tube to the rotor peeling point is 49.776 mm, as shown in Table 2; L zgThe length of the yarn guide twist-stop tube is 50mm, as shown in Table 2. Therefore, under the spinning process described in Table 1, the tail length L is... x The minimum should be 211.901mm, and the maximum should be 236.901mm. It is known that the speed of the yarn feed roller during the tail-holding phase is 50% of the set value, i.e., V... y = 33.33 m / min, according to equation (23), with the minimum tail length L x Substituting 211.901mm into the calculation (i.e., the end of the yarn is at the bottom of the yarn guide tube at this point), the yarn guide roller running time t is then calculated. x for:

[0224]

[0225] (8) Seed yarn release length and yarn storage length:

[0226] As shown in Figure 13, the overlap length is the length of the transition section of the seed yarn. Given that the tail yarn stops at the bottom of the yarn guide tube after power failure, according to equation (25), the seed yarn release length L ζ for:

[0227]

[0228] Where L B The distance from the bottom of the yarn guide twist-stop tube to the rotor peeling point can be found in Table 2. Given the seed yarn release length, set the yarn guide roller reversing speed V. y1 =86.664m / min, then the release delay t7 is:

[0229]

[0230] Given that the stored yarn length is generally 20mm-50mm longer than the seed yarn release length, and taking the stored yarn length to be 30mm longer than the seed yarn release length, according to formula (24), the stored yarn length L is... C for:

[0231] L C =L ζ +30=98.861+30=128.861mm(44)

[0232] Given that the reversing speed of the winding roller is V j =291.659m / min, then the reversal time t of the winding roller is... j for:

[0233]

[0234] (9) Twisting time:

[0235] During splicing, the rotor speed and yarn feeding speed are 50% of the set values, i.e., n z =25000rpm, V y =33.33m / min, then the initial twist T0 = n z / V y =750 twists / m; the maximum twist coefficient of the warp yarn is obtained from "Spinning Science" as α. t =480, yarn linear density is ρ y =37.6tex, then the twist of the joint should be equal to the twist corresponding to the maximum twist coefficient, that is According to the instantaneous twist theory of the inner yarn arm of the spinning cup based on equation (26), the overlap length is known to be... The twisting time t8 is:

[0236]

[0237] (10) The shape and structure of the joint:

[0238] According to equation (27), combined with the yarn sinking delay t6, release delay t7 = 0.068s, twisting delay t8 = 0.038s, and the diameter D of the rotor coagulation tank... Z =36mm, given that the feeding speed of the cotton roller at the joint is 50% of the set value, i.e., V1 = 0.2789m / min, and the fixed weight of the cotton sliver is ρ s =45g / 10m, then the linear density ρ of the fiber ring r for:

[0239]

[0240] If the overlap length is equal to the length of the tail yarn transition section, then the maximum linear density of the seed yarn in the cohesion tank is the set yarn linear density ρ. y =37.6 tex; the maximum linear density of the newly fed fiber stream is the set yarn linear density ρ y = 37.6 tex; According to equation (31), the overlap length is known to be Then, the linear densities ρ1 (tex), ρ2 (tex), and ρ3 (tex) corresponding to thick section 1, thin section 2, and thick section 2 in the joint structure of Figure 13 are:

[0241]

[0242] By adjusting the sedimentation delay t6 in formula (48), the linear density of the two coarse sections and one fine section of the joint can be adjusted, thereby achieving the control of the joint shape. If t6 = 0.1s is taken, the maximum linear density of the joint is ρ1 = ρ3 = 75.5tex, and the minimum linear density is ρ2 = 54.4tex.

[0243] This invention addresses the issue of yarn breakage during rotor spinning due to temporary shutdowns or power outages. It utilizes a UPS (Uninterruptible Power Supply) to provide backup power, controlling the operation of various components of the rotor spinning machine. By precisely calculating the remaining fiber length of the spinnable yarn after passing through the rotor, the invention guides the orderly shutdown of mechanisms such as the guide roller and winding roller, ensuring the broken yarn end stops within the twist stopper's guide tube, thus achieving automatic yarn tail retention during shutdown. Upon restarting or when power is restored, the doffing mechanism unwinds the broken yarn as seed yarn into the rotor's condensing groove. This yarn overlaps and twists with the fiber flow formed by the cotton sliver fed into the condensing groove via the combing roller and fiber conveying channel, completing the splicing action. Based on the yarn tail position of the automatic tail retention function, the invention further adjusts parameters such as linear density, twist, and strength of the seed yarn-fiber flow twist by precisely calculating the overlap length and twisting time, thereby improving the splicing success rate and achieving high-quality automatic splicing. It enables efficient and automated completion of automatic tail-keeping and automatic splicing functions during temporary stops or power outages in rotor spinning, thereby improving enterprise production efficiency.

[0244] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for automatic splicing of rotor spinning based on adjusting the tail length of the yarn, characterized in that, For rotor spinning machines with backup power, the tail yarn position is adjusted when the machine stops due to power failure. The following steps A to B are performed to implement the shutdown tail yarn retention method: Step A: The carding roller and rotor stop naturally according to their own inertia. At the same time, the cotton feeding roller, yarn guiding roller and winding roller are decelerated based on the backup power and PLC control, and then proceed to step B. Step B. The PLC control sends a stop feeding command to the feeding roller, controlling the feeding roller to instantly reverse and stop. At the carding roller spacing point, the cotton sliver conveyed by the feeding roller is broken. Under the operation of the yarn guide roller and the winding roller, the fibers remaining in the carding roller, fiber conveying channel, and rotor are transformed into yarn under the action of the carding roller, fiber conveying channel, rotor, yarn guide roller, and winding roller. At the same time, the yarn guide roller and the winding roller are controlled to wind the yarn onto the winding mechanism, stopping the end of the yarn in the yarn guide twist-stopping tube, and controlling the yarn guide roller and the winding roller to stop.

2. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 1, characterized in that: Based on the control of the process of overlapping the new fiber ring formed in the rotor coagulation tank with the tail yarn after the spinning is restarted by powering on, the splicing method is as follows: steps C to E. Step C. Control the rotor and combing roller to start working, and control the winding roller to reverse. The unwound yarn is stored in the yarn storage tube as seed yarn under the action of negative pressure airflow. Then control the winding roller to stop and proceed to step D. Step D. Control the start of the cotton feeding roller to feed cotton sliver. The cotton sliver is separated into fibers by the combing roller and fiber conveying channel, and then conveyed to the coagulation tank in the rotor to coagulate and form a fiber stream. Then proceed to step E. Step E. Control the yarn guide roller to reverse, release the seed yarn in the yarn storage tube and sink it into the coagulation tank in the rotor under the action of negative pressure airflow. It overlaps with the fiber flow in the coagulation tank, twists and wraps with each other to achieve splicing, and continues to spin the rotor to generate yarn. Then control the yarn guide roller and winding roller to rotate forward, continuously output the generated yarn and wind it into a cone.

3. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 1, characterized in that: In step B of the shutdown and tail-retention method, the fibers remaining in the combing roller, fiber conveying channel, and rotor include residual fibers from the instantaneous reverse output of the cotton feeding roller, residual fibers in the combing roller, residual fibers in the fiber conveying channel, residual fibers on the sliding surface of the rotor, and residual fiber rings in the coagulation groove of the rotor. These fibers are transformed into yarn of length L under the action of the combing roller, fiber conveying channel, rotor, yarn guide roller, and winding roller. Ω Obtain as follows, then based on the length L of the yarn converted. Ω Control the operation of the yarn guide roller and the winding roller, stop the end of the yarn in the yarn guide twist tube, and finally control the yarn guide roller and the winding roller to stop rotating. First, based on the sum of the following weights (Ω1, Ω2, Ω3, Ω4, Ω5) of the sliver fibers transferred away by the combing roller during the instantaneous reverse rotation of the feed roller, the residual fibers in the combing roller, the residual fibers in the fiber conveying channel, the residual fibers on the sliding surface in the rotor, and the residual fiber rings in the coagulation trough in the rotor, Ω5, the weight of the sliver fibers is calculated as follows: Obtain the total residual fiber weight Ω corresponding to the number i of fiber rings in the rotor condensation tank, and the remaining residual fiber weight Ω that is less than one complete fiber ring. σ ; Then regarding the weight Ω σ The remaining residual fibers, due to the rotor cup coalescence effect, gradually accumulate in the cohesion tank of the rotor cup to form fiber rings that gradually decrease in size, according to L... σ =(Ω) σ ×2) / ρ y Obtain the length L corresponding to the yarn tail. σ , where ρ y Indicates the linear density of the yarn; Finally, according to L Ω =L σ +L τ =(Ω) σ ×2) / ρ y +i×π×D Z Obtain length L Ω , where D Z L represents the diameter of the condensation tank in the rotating cup. τ This indicates the length of the yarn corresponding to all remaining fibers.

4. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 3, characterized in that, The weight Ω1 of the residual fibers output during the instantaneous reverse rotation of the cotton roller is obtained as follows: Based on the length L of the fiber held between the gripping point of the cotton feeding roller and the spacing point of the combing roller. 12 Press Ω 12 =L 12 ×ρ s The weight Ω of the held fiber is obtained. 12 , where ρ s This indicates the fixed weight of the cotton swabs fed into the cotton roller; Then, according to the fiber transfer rate k of the instantaneous reverse rotation of the cotton roller towards the combing roller, Ω1 = Ω 12 ×k, to obtain weight Ω1.

5. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 3, characterized in that, The weight Ω2 of the residual fibers in the combing roller is obtained as follows: according to Obtain the arc length L of the combing roller f The corresponding time t1, where L f n represents the arc length of the combing roller from the point where the combing roller is positioned to the fiber conveying channel. f D represents the rotational speed of the combing rollers. f Indicates the diameter of the combing roller; Then press Ω2=t1×V y ×ρ y The weight Ω2 is obtained, where V y ρ represents the linear velocity of the yarn drawing roller. y This indicates the linear density of the yarn.

6. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 3, characterized in that, The weight Ω3 of the residual fibers in the fiber transport channel is obtained as follows: First, let V2 = V f =η2×n f ×π×D f The linear velocity V2 at the fiber conveying channel inlet is obtained, where η2 represents the correction coefficient for converting the combing roller linear velocity into fiber transfer velocity, and n f D represents the rotational speed of the combing rollers. f V represents the diameter of the combing roller. f Indicates the linear speed of the combing rollers; Simultaneously, according to V3=η3×π×n z ×D Z1 The linear velocity V3 at the fiber conveying channel outlet is obtained, where η3 represents the correction coefficient for converting the rotor linear velocity into fiber transfer velocity, and n z D represents the rotational speed of the rotor. Z1 This represents the diameter of the corresponding circle on the sliding surface of the rotor. Then press The fiber flow transfer time t2 within the fiber transport channel is obtained, where L2 represents the length of the fiber transport channel; finally, according to Ω3 = t2 × V y ×ρ y The weight Ω3 is obtained, where V y ρ represents the linear velocity of the yarn drawing roller. y This indicates the linear density of the yarn.

7. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 3, characterized in that, The weight Ω4 of the residual fibers on the sliding surface in the rotor is obtained as follows: First, based on the rotor radius r and angular velocity ω corresponding to the point on the rotor's sliding surface when the fiber is transferred, and taking the fiber at that point as the fiber particle, we obtain the centrifugal force F1 acting on the fiber particle, the component of the fiber particle along the rotor wall towards the condensation tank F2, the component of the fiber particle perpendicular to the rotor wall F3, the acceleration a of the fiber particle along the rotor's sliding surface, the mass m of the fiber particle, the coefficient of friction μ between the fiber and the rotor wall, and the rotor's inner wall inclination angle γ. The dynamic equations are then constructed as follows: Next, let t3 be the time it takes for the fiber to transfer from the fiber conveying channel outlet to a certain position on the inner sliding surface of the rotor. Then, based on the length x that the fiber slides along the generatrix of the rotor sliding surface during this time, and differentiating the acceleration a in equation (11), we obtain the following: Then, based on the entire sliding process of the fiber transferring from the fiber conveying channel outlet to the rotor condenser, x and r in equation (12) have a linear increasing relationship, and the following structure is constructed: Among them, L h D represents the distance along the rotor's generatrix from the fiber conveying channel outlet to the position of the internal coagulation tank. Z This is expressed as the diameter of the condensation tank; Combining equations (11), (12), and (13), when the fiber slides from the fiber conveying channel outlet into the coagulation tank inside the rotor, i.e., x = L h Then, by using the characteristic root method, according to the following formula (14): Calculate the time t3 during which the fiber slides from the fiber conveying channel outlet to the coagulation tank inside the rotor. Finally, press Ω4 = t3 × V y ×ρ y The weight obtained is Ω4, where V y This indicates the linear speed of the yarn drawing roller.

8. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 3, characterized in that, The weight Ω5 of the residual fiber rings in the coagulation tank of the rotating cup is calculated according to... Obtain weight Ω5, where ρ y D represents the linear density of the yarn. Z This indicates the diameter of the condensation tank in the rotating cup.

9. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 3, characterized in that: Based on the length L of the yarn transformed Ω According to the following formula: Determine the control of the lead-in length L for the lead-in roller and winding roller. x The yarn is wound onto the winding mechanism, and the yarn end is stopped inside the yarn guide tube, where t x This indicates the length L corresponding to the drawing roller and the winding roller, respectively. x Yarn running time, V y This indicates the length L corresponding to the drawing roller and the winding roller, respectively. x The linear velocity of the yarn, L B L represents the length from the bottom of the yarn guide twist-stop tube to the peeling point inside the rotor. zg This indicates the length of the yarn guide twist-stop tube.

10. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 2, characterized in that: In step E of the splicing method, the yarn guide roller is reversed, and the seed yarn in the yarn storage tube is released and sinks into the coagulation tank in the rotor under the action of negative pressure airflow, so that the seed yarn overlaps with the fiber flow in the coagulation tank, and the upper limit of the overlap length is the circumference of one rotor coagulation tank. In the overlapping state, the fiber flow condensed in the rotor coagulation tank forms a fiber ring.

11. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 10, characterized in that: Before steps C to E of the joint method are executed, the various control parameters are adjusted as follows: For the winding roller at speed V j Reverse time t j The unwinding length of the winding mechanism is L C The yarn is stored in a yarn storage tube as seed yarn under the action of negative pressure airflow, and the following model is constructed: Among them, L ζ This indicates the length of the seed yarn released from the yarn storage tube when the yarn guide roller reverses in step E. a1 and a2 represent L respectively. C Compared to L ζ The preset lower limit length and preset upper limit length for upward movement; Based on the definition in step E, the yarn-drawing roller is controlled at a speed of V. y1 Reverse time t7 to construct the overlap length between the seed yarn in the yarn storage tube and the fiber flow in the coagulation tank. The length L of the seed yarn released from the yarn storage tube by the yarn guide roller ζ The relationship between them is as follows: Among them, L B L represents the length from the bottom of the yarn guide twist-stop tube to the peeling point inside the rotor. zg t7 indicates the length of the yarn guide twisting tube, and t7 indicates the time elapsed from the start of the yarn guide roller reversing to release the seed yarn to the stop time. Based on yarn linear density ρ y Twist coefficient α t Then the critical twist And according to the rotor speed n z Yarn drawing speed V y Then the initial twist T0 = n z / V y Further based on the overlap length With twisting time t8 and splice twist T1, based on the instantaneous twist theory of the inner yarn arm of the spinning cup, the following structure is constructed: The control of the seed yarn-fiber flow twisting time t8 is based on the twist coefficient α. t and critical twist For reference, by controlling the overlap length Implementation; According to the method of stopping the machine and leaving the tail, the working lead-out length L of the yarn-drawing roller and the winding roller is adjusted. x The yarn is wound onto the winding mechanism, the position of the yarn tail end within the yarn guide tube is determined, and the overlap length is considered. According to formula (25), the length L of the seed yarn released from the yarn storage tube by the yarn guide roller is determined. ζ The control is further adjusted according to formula (24), which controls the length L of the unwound yarn on the winding mechanism of the winding roller. C Adjustments are made based on the overlap length. The twisting time t8 is controlled by formula (26), thereby determining the various control parameters in steps C to E of the jointing method.

12. The method for automatic splicing of rotor spinning based on adjusting the tail yarn length according to claim 10, characterized in that, The execution of steps C to E of the joint method also includes steps F to G as follows: A method for adjusting the joint morphology and structure based on the joint linear density distribution. Step F. First, perform the joint line density distribution analysis as follows: The joint consists of three parts: the fiber ring superimposed on the rotor cohesive trough from the start of feeding the cotton sliver into the cotton roller until the start of the winding device to guide the yarn; the seed yarn that enters the rotor cohesive trough within the release delay t7; and the newly fed fiber flow into the rotor cohesive trough when the yarn is started. The weight of the fiber ring is determined by the following three time periods from the start of feeding the sliver into the cotton roller to the start of the winding device: the yarn sinking delay t6, the release delay t7, and the twisting delay t8. The yarn delay time t6 refers to the time from when the cotton sliver is fed into the cotton roller to when the yarn guide roller begins to reverse and release the seed yarn; Release delay t7 refers to the time from the start of the yarn feeding roller reversing to release the seed yarn until it stops; Twisting delay t8 refers to the twisting time after the seed yarn and fiber ring overlap to form a twisted body, that is, the time from when the seed yarn is released from the starting roller to when the winding device starts to start the yarn. Based on the feeding speed V1 of the tampons into the cotton roller and the fixed weight ρ of the tampons... s The weight Ω6 of the fiber ring is obtained as follows; Ω6=(t6+t7+t8)×V1×ρ s (27) Regarding the weight of the seed yarn entering the rotor condenser within the release delay t7, based on the total remaining fibers including those of length L... τ The yarn and its length are L σ The yarn tail, according to the corresponding weight Ω σ ρ, the density of the yarn y Combining the overlap length of seed yarn and fiber flow As follows: The weight Ω7 of the seed yarn that enters the rotor coagulation tank within the release delay t7 is obtained; Regarding the weight of the newly fed fiber stream in the rotor cohesive trough at the start of yarn feeding, based on the fiber merging effect in the rotor cohesive trough, it is calculated using the following formula: The weight of the newly fed fiber stream in the rotor coagulation tank at the start of yarn feeding is Ω8; Then follow the formula below: The total weight of the fibers at the joint is Ω. w ; Step G. Adjustment of joint morphology and structure: Given that fibers with a weight of Ω6 are distributed in the form of fiber rings around the rotor condenser, and considering the fiber coalescence effect in the rotor condenser, the distribution of the newly fed fiber stream with a weight of Ω8 around the condenser is linear. Therefore, the linear density of the fiber rings is ρ. r =Ω6 / (π×D) Z The maximum linear density of the newly fed fiber stream is set to ρ. y and combined with a length of L σ The maximum linear density of the yarn tail is set to ρ. y That is, the maximum linear density of the seed yarn in the rotor condenser is ρ y Taking the debonding point inside the rotor as a reference, within the circumference of a coagulation tank, the morphological structure changes from left to right at the joint as follows: coarse section 1 → fine section → coarse section 2. Let the linear densities of coarse section 1, fine section, and coarse section 2 be ρ1, ρ2, and ρ3, respectively, then the structure is as follows: Then, based on the overlap length According to formula (26), the twisting time t8 is adjusted to control the twist of the joint T1. Combined with the sand settling delay t6 and the release delay t7, the maximum and minimum linear density of the joint are controlled to achieve the regulation of the joint shape and structure.

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