Precision control method for transmission tension of printing film coating production line

Abstract

According to the printing film coating production line transmission tension precision control method, a DCS system carries out process control of production line temperature, humidity, air volume and flow variables, analytic calculation of a controlled variable trend chart and man-machine interaction, and AC80 + ACS600 forms a transmission subsystem of Freelance2000; the AC80 PLC establishes sequential logic control required by a production line, carries out PID closed-loop control on tension or positions of all transmission points, calculates given speed and given torque of all the transmission points in combination with synchronous speed, and transmits signals of given speed, given torque, start and stop and the like to the ACS600 frequency converters of the 14 transmission points through DDCS protocol communication. And each transmission point forms speed closed-loop control through an ACS600 frequency converter and a speed measurement encoder, transmission control of the coating production line is cooperatively established, and the dragging points are synchronous in speed, stable in tension and consistent in longitudinal uniformity of a coating. The winding taper tension is controlled under the moment mode of the printing film production line, the appearance of a winding reel is neat, and the tension tightness is proper.

Description

Technical Field

[0001] The present application relates to a control method for a printing film coating production line, and in particular to a precise control method for transmission tension of a printing film coating production line, belonging to the technical field of printing coating production line control. Background Art

[0002] In industrial production such as papermaking, printing and dyeing, packaging, wire and cable, textile, metallurgy and other industries, accurate and stable film speed and tension control, as well as winding / unwinding electrical control are required to maintain constant tension or require the tension to change according to a set curve to improve product quality.

[0003] Computer-to-plate systems are rapidly gaining popularity around the world, gradually replacing printing films. However, the CTF process, which uses film to print images onto PS plates for printing, is still very popular, and the absolute consumption of printing films is still very large. At the same time, the printing film production line can also produce other new products such as silver salt PCB films (printed circuit board films), medical printing films, etc. On the other hand, it also serves as a reference for other production lines, so the research and development and improvement of printing film coating production lines are of great significance.

[0004] Coating machines are used for surface coating production of films, paper, etc., which coats the rolled substrate with a layer of glue, paint or ink with specific functions, and then rewinds it after drying. Generally, they are equipped with a special multi-functional coating head, which can realize various forms of surface coating production.

[0005] The performance improvement of coating machines in the development process is reflected in: 1) The width of coating machines has increased from about 1000mm in the early days to the current maximum of 10000mm; 2) The speed of coating machines has increased from 20-30m / min at the beginning of the last century to 2500m / min; 3) The newly developed most advanced spray coating (Spray Coating) has been put into actual production; 4) The drying after coating has developed from the simplest hanging fur hot air drying in the early days to the current suspended hot air drying and infrared drying; 5) The solid content of the coating that the coating machine can adapt to can be adjusted according to the requirements of the coating type, and the maximum solid content can reach 50-70%; 6) With the development of automatic control technology, the automation level and control accuracy of coating machines have also been greatly improved, and the operation is more convenient.

[0006] The problems that need to be solved in the control of the printing film coating production line in the prior art and the key technical difficulties of this application include:

[0007] (1) The speeds of the various drag points of the printing film coating production line in the prior art are not synchronized, the tension is not stable, and the longitudinal uniformity of the coating is inconsistent. The inverter + PLC has not been introduced, the automation level of the production line is low, various logical relationships cannot be realized, the system response time is long, there is a lack of a good human-computer interaction interface, and the fault self-diagnosis function cannot be realized. The original production line control is DC speed regulation + speed measuring motor + relay + single-chip microcomputer. The speed regulator belongs to analog control, and the corresponding potentiometer must be adjusted when changing parameters. The entire system has problems such as low vehicle speed accuracy, large tension fluctuations, slow system response, and difficulty in finding faults. The existing technology cannot solve the problem of high coating accuracy requirements. There is a lack of speed distribution for 14 drag points, and synchronization cannot be guaranteed. The operation of each drag point is not stable, the tension of each section fluctuates greatly, and the film path tension cannot be guaranteed. The film path speed accuracy between 6D and 7D is greater than ±0.1%, and the other drag points are greater than ±1%. The tension control accuracy is greater than ±1%, and the position loop accuracy is greater than ±1%. It cannot meet the transmission tension precision control requirements of the printing film coating production line.

[0008] (2) The existing printing film production line has poor control of winding taper tension in torque mode, uneven winding reel appearance, and inappropriate tension tightness. It is impossible to solve the problems of constant tension unwinding, taper tension winding, and the uniformity of the winding shaft. The program cannot realize real-time roll diameter calculation, speed control, and torque control switching. During winding, the PET film is a processed part and also a rotating part that participates in the transmission of motion and power. The film itself is neither a rigid body nor a pure elastic body, and its power and motion characteristics are relatively complex. The original design winding length was 1800 meters. After winding to 2400 meters, the winding tension was unstable, the winding was uneven, and the edges were jagged or curved. Air entrained between the layers caused film wrinkles, or the film in the axis was squeezed out. If the winding tension is too small, it will cause the reel to stagger during the winding process or transportation process, and displacement between the layers. As the roll diameter increases, the winding tension should be decayed according to a certain rule to form tension taper winding. The existing technology lacks accurate and stable film speed and tension control, lacks electrical control for rewinding / unwinding, and cannot maintain constant tension or require the tension to change according to a set curve, which restricts production quality.

[0009] (3) The transmission system of the prior art film coating production line cannot meet the characteristics of the coating production process and the process requirements of the production line. The frequency conversion transmission and tension control are poor. There is a lack of process control of the production line temperature, humidity, air volume and flow variables and analytical calculation of the trend diagram of the controlled variables and human-computer interaction. There is a lack of sequential logic control required for the production line. The tension or position of each transmission point cannot be PID closed-loop controlled. The speed setting and torque setting of each transmission point cannot be calculated in combination with the synchronous speed. The speed setting, torque setting and start and stop signals cannot be transmitted to the ACS600 inverter of the 14 transmission points. Each transmission point cannot form a speed closed-loop control. Due to the particularity of the film, the winder is prone to uneven winding. The running speed of the production line is unstable, the tension of each area, the position of the floating wheel and the position of the film storage rack are not smoothly controlled, and the winding uniformity is low, which cannot meet the process requirements of printing film production. Summary of the invention

[0010] The coating production line control improved in this application consists of two parts: the DCS system Freelance2000 and the transmission system AC80+ACS600. The DCS system Freelance2000 performs process control of the production line temperature, humidity, air volume and flow rate variables, analytical calculation of the controlled variable trend chart, and human-computer interaction. AC80+ACS600 constitutes the transmission subsystem of Freelance2000 and is connected to Freelance2000 through the MODBUS communication protocol. AC80PLC establishes the sequential logic control required for the production line and controls each transmission point. The tension or position is controlled by PID closed loop, and the speed setting and torque setting of each transmission point are calculated in combination with the synchronous speed. The PLC transmits the speed setting, torque setting and start and stop signals to the ACS600 inverter of 14 transmission points through the NDBU-95 optical fiber distribution unit and DDCS protocol communication. Each transmission point then forms a speed closed loop control through the ACS600 inverter and the speed encoder, and cooperates to establish the transmission control of the coating production line. Based on the particularity of the film, the winder is improved to solve the apparent shortcomings of uneven winding; the speed between each dragging point is synchronized, the tension is stable, and the longitudinal uniformity of the coating is consistent. The winding taper tension control in the torque mode of the printing film production line, the winding reel is neat in appearance, and the tension tightness is appropriate, which meets the precise control requirements of the transmission tension of the printing film coating production line.

[0011] In order to achieve the above technical effects, the technical solutions adopted in this application are as follows:

[0012] The precise control method of transmission tension of printing film coating production line is based on the production process characteristics of printing film coating and the process defects of the production line, and the variable frequency transmission and tension control are optimized to improve the transmission system of the film coating production line;

[0013] The improved coating production line control consists of two parts: DCS system Freelance2000 and transmission system AC80+ACS600. The DCS system Freelance2000 performs process control of production line temperature, humidity, air volume and flow rate variables, analytical calculation of controlled variable trend charts and human-computer interaction. AC80+ACS600 constitutes the transmission subsystem of Freelance2000 and is connected to Freelance2000 through MODBUS communication protocol. AC80PLC establishes the sequential logic control required by the production line, performs PID closed-loop control on the tension or position of each transmission point, and calculates the speed setting and torque setting of each transmission point in combination with the synchronous speed. PLC transmits speed setting, torque setting and start-stop signals to the ACS600 inverter of 14 transmission points through NDBU-95 optical fiber distribution unit and DDCS protocol communication. Each transmission point then forms a speed closed-loop control through the ACS600 inverter and speed encoder, and cooperates to establish the transmission control of the coating production line. Based on the particularity of the film, the winder is improved to solve the apparent problem of uneven winding.

[0014] 1) Improvement of the transmission system of the printing film production line, including: building the hardware structure of the printing film production line, optimizing the transmission control of the printing film production line, and setting the speed of the tension ring of the printing film production line;

[0015] 2) Improvement of tension control of unwinding / winding machine of printing film production line, including: improvement of tension control of unwinding / winding machine and further optimization of winder;

[0016] In combination with the special requirements of printing film for winder / unwinder, a tension, torque and speed relationship model of winder / unwinder is established to realize constant tension control of unwinder and taper tension control of winder.

[0017] Preferably, the hardware structure of the printing film production line is constructed: three operation stations are set up: one engineer station ES and two operator stations OS. The engineer station can also be used as an operator station. The engineer station is set up for programming, drawing, debugging and document management of coating process control; the operator station is set up for operation, monitoring, recording, diagnosis and trend analysis of coating process control and coating transmission control;

[0018] The control center of the AC80 coating drive control system and the frequency converter ACS600 jointly complete high-efficiency and high-precision drive control, including production line sequence and interlocking settings. The entire system includes two AC80PLCs, which are connected to the rectifier unit and inverter through NDBU-95 optical fiber distributors respectively. The two AC80 PLCs communicate with each other through the AF100 protocol.

[0019] Preferably, the transmission control of the printing film production line is optimized:

[0020] 1) Public DC bus: The whole system adopts a public DC bus, and the rectifier unit and inverter unit of the inverter are separated and installed in their own control cabinets. The rectifier unit rectifies the AC with constant voltage and frequency into DC with constant voltage, and forms a public DC bus. The inverter units are hung on the public DC bus, and the DC with constant voltage is inverted into AC with adjustable voltage and frequency, which is used to drive the motor. The public DC bus inverter is equipped with one rectifier unit and can hang multiple inverter units to drive multiple motors. The public DC bus power supply mode is divided into rectifier unit and rectifier feedback unit. The rectifier feedback unit is used in systems requiring fast braking and large inertia;

[0021] The layout of the field control cabinet is also divided into two parts, the DCS part and the transmission control part. The transmission control cabinet is further divided into auxiliary control cabinet, rectifier cabinet, inverter cabinet, and PLC control cabinet.

[0022] 2) ACS600 inverter: The entire production line drive control consists of 14 drive points, each of which is driven by an ABB ACS600 inverter. The ACS600 inverter uses direct torque control DTC and sets a high-dynamic performance AC motor variable voltage and frequency speed regulation. In its speed loop, it uses current feedback to directly control the motor's magnetic flux and torque.

[0023] Directly use the space voltage vector to calculate and control the torque and flux of the motor in the stator coordinate system; adopt the stator magnetic field orientation, with the help of discrete two-point regulation to generate PWM to directly control the switching state of the inverter optimally, and obtain high dynamic performance of the torque;

[0024] Each switch of direct torque control is determined by the value of flux and torque. The motor's flux and torque are calculated through the motor's stator voltage and current with the help of instantaneous space vector. The difference compared with the given value is used to optimize the pulse selector to determine the optimal switching position of the inverter, thereby achieving direct control of flux and torque.

[0025] 3) Encoder: A three-channel incremental rotary encoder is used as a speed feedback device. Based on photoelectric measurement, the rotary encoder outputs 2048 pulse signals through each rotation of the shaft, and there are two pulse signal outputs. From the end of the shaft, the phase pulse of channel B leads the phase pulse of channel A by 90° in the clockwise direction, and the phase pulse of channel A leads channel B by 90° in the counterclockwise direction. Channel C is the origin signal. The pulse signal of the pulse encoder is output to the inverter NTAC-01 module. After the module sorts the pulse waveform, it is transmitted to the inverter through optical fiber for speed feedback detection.

[0026] 4) Speed ​​distribution: The speed chain of the entire production line is distributed with the 6D in front of the coating head as the main speed, which is hard given without tension or position loop. The rest are based on the synchronous speed and add their own tension loop or position loop PID output as the speed given, between the coating extrusion nozzle 6D and 7D, to ensure the sheet path speed and tension accuracy between 6D and 7D;

[0027] 5) Tension, position and speed closed-loop control: except 6D, tension loops or position loops are set at other transmission points, forming a double closed-loop system with speed and tension loops or position loops. Each transmission point is mainly based on synchronous speed, supplemented by tension loops or position loops, so that each transmission point can ensure the appropriate film path tension or film storage rack position on the basis of synchronous speed.

[0028] 6) Set the electrical parameters of each transmission motor: the extrusion coating nozzle is between 6D and 7D. The speed and tension fluctuations of the film path in this interval directly affect the longitudinal uniformity of the coating. 6D and 7D adopt the motor direct connection method.

[0029] Preferably, the speed of the tension ring of the printing film production line is set: the given speeds of the transmissions 7D, 8D, and 9D are calculated accordingly, the synchronous speed is added with the speed correction calculated by the tension PI controller, the speed correction is limited to prevent sudden changes in speed, and the speed stability is ensured, the speed correction is put in when the transmission speed increases to 95% of the given value of the synchronous speed, when the stop signal is received, the speed correction is cut off, and the transmission stops at the set deceleration time ramp;

[0030] The speed setting of the position loop is consistent with that of the tension loop. The speed setting of transmission 3D, 4D, 5D, 10D, and 11 / 12D is calculated accordingly. The synchronous speed is added to the speed correction calculated by the position PI controller. The speed correction is limited to prevent sudden speed changes. The film rack control and floating roller control also belong to the position loop control. The difference lies in the length of the integral time. The film rack is proportional control with an integral time of 10ms, and the floating spoke is proportional integral control with an integral time of 3000ms. In addition, the film rack is also equipped with some logical controls, including roll changing, bar pressing, recovery, and overspeed operation.

[0031] Preferably, the tension control of the winding / unwinding machine is improved: ACS600 inverter + AC80PLC is used to realize the winding / unwinding tension control of the film, 1D and 2D form a double-station unwinding device with constant tension control, 13D and 14D form a double-station winding device with taper tension control;

[0032] 13D winding adopts tension closed-loop control in torque mode. The AC80PLC calculates the winding diameter, speed setting, and torque compensation. The ACS600 inverter drives the winding motor according to the speed and torque signals output by AC80, and does not calculate the speed, torque, and winding diameter.

[0033] The coil diameter calculation is performed through the TC block DIA_CALC. The actual coil diameter is calculated by the line speed and the actual motor speed. The specific process is to divide the actual line speed of the previous level 12D by the motor speed of 13D, and the result is obtained by slope integration operation. The actual coil diameter of 13D is obtained by the change rate of the coil diameter limited by the maximum thickness of the coil;

[0034] In the curling application, the input line speed is divided by the motor speed, and the result of the quotient is calculated by the slope integration. The maximum thickness of the coil limits the change rate of the coil diameter to obtain the coil diameter of the material. The coil diameter calculation is based on internal calculation and does not require additional equipment. The block also allows the use of external coil diameter sensors. The coil diameter memory program maintains the coil diameter data under any circumstances, including after power failure, reduces tension disturbance during the process of stopping or restarting the roller, and sets a resettable coil diameter data. When it is necessary to temporarily keep the coil diameter value constant, the coil diameter calculation can be paused through the digital input port;

[0035] According to the actual winding diameter of 13D, the torque setting of 13D is calculated by T = (F*D) / (2*I), T is the output torque command of the inverter, F is the tension setting command, D is the winding diameter of the reel, I is the mechanical transmission ratio, and 13D realizes closed-loop torque tension control;

[0036] In the film production line control, ABB AC80PLC calculates the torque reference through the TORQ_CTL function block. First, the input tension reference value is calculated, multiplied by the coil radius, and the static friction torque and dynamic friction torque are compensated to obtain the transmission torque reference. Second, the tension reference output of the tension regulator is processed, multiplied by the coil radius, and the corresponding torque correction is given within the specified adjustment range.

[0037] AC80 sends torque setting and start / stop and other related signals to ACS600 through DDCS drive bus to complete winding. AC80 is responsible for all winding calculations.

[0038] Preferably, further optimization of the winder:

[0039] Improvement 1: The steel frame of the winder is enlarged and thickened to increase the load and stability of the winder.

[0040] Improvement 2: Increase the torque of the winder: the length of the winding reel is changed from 1800 meters, diameter 450 mm, and weight 400 kg to 3200 meters, diameter 700 mm, and weight 710 kg. The motor power is increased from the original 4.0 KW to 7.5 KW, and the motor shaft is directly connected to the winding reel.

[0041] Improvement 3: Adjustment of the moment of inertia of the winder: After the winder is modified, the moment of inertia and static friction coefficient are gradually adjusted to an ideal state based on experience and trial and error;

[0042] Improvement Four: Modify the electrical and instrument parameters of the coating drive system, including increasing the negative pressure of 11D and 12D and adjusting the PID parameters.

[0043] Preferably, further optimization of the rewinder:

[0044] Improvement Five: Add an adjusting wheel: Add a film receiving adjusting rod on the rewinder to further solve the problem of the tangent value of the film base. When loading the film on the production line, it is specified that the film is loaded with the same tightness. The tight side is fixed to one side of the production line. On the other hand, add a film receiving adjusting rod on the rewinder. By adjusting the adjusting handle, manually fine-tune the left and right tightness of the film path on the rewinder;

[0045] Improvement Six: Add a film edge embossing device: Increase the film edge friction force and reduce the relative sliding between film layers. By adding an embossing wheel, hot-press patterns on both sides of the film path to increase the film edge friction force and reduce or avoid the deformation of the reel;

[0046] Preferably, further optimization of the rewinder:

[0047] Improvement Seven: Change the rewinding tension curve: The factors causing uneven rewinding include two major aspects: the characteristics of the film itself and the performance of the rewinder. Among the characteristics of the film itself, the dominant factors are the friction coefficient of the film and the tangent value of the film base. Regarding the friction coefficient, the larger the friction coefficient, the easier it is to wind evenly. The anti-halation film has better winding neatness than the emulsion film. The tangent value of the film base should also be controlled within ±1 mm / 3 m;

[0048] After determining the initial tension and the tension taper coefficient, the entire curve is determined and changed to a segmented tension curve. Specifically, divide the entire rewinding tension into 5 segments according to the actual situation, and each segment corresponds to an attenuation slope. Add the following to the central control operator station screen:

[0049] The tension calculation in the program is:

[0050] For the first segment, F = F 0 -(D - 200) / (D 1 - 200)×F 0 ×K 1 ;

[0051] For the second segment, F = (F 0 - F 0 K 1 ) - (D - D 1 ) / (D 2 - D 1 )×F 0 ×(K 2 - K 1 );

[0052] For the third segment, F = (F 0 - F 0 K2 )-(D - D 2 ) / (D 3 -D 2 )×F 0 ×(K 3 -K 2 )

[0053] Paragraph 4: F = (F 0 -F 0 K 3 ) - (D - D 3 ) / (D 4 -D 3 )×F 0 ×(K 4 -K 3 )

[0054] Paragraph 5: F = (F 0 -F 0 K 4 ) - (D - D 4 ) / (D 5 -D 4 )×F 0 ×(K 5 -K 4 )

[0055] Where: F is the real - time set tension, F 0 is the initial tension value, D is the real - time coil diameter, K 1 , K 2 , K 3 , K 4 , K 5 are the slopes of the 1st - 5th segments, D 1 , D 2 , D 3 , D 4 , D 5 are the coil diameters of the 1st - 5th segments;

[0056] The operator segments according to the specific situation and inputs the corresponding winding tension. When there is a deviation during winding between the 4th and 5th coil diameter segments, the slope of the 5th segment is adjusted appropriately, and at the same time, the previous winding situation is not affected. If there are indentations on the axis, the initial tension is reduced and the slope of the 1st segment is increased.

[0057] Preferably, further optimization of the winding machine:

[0058] Improvement 8: Adding a gap-type winding device: For high-speed, wide-width winders, the neatness of the two sides of the reel is further increased, and a gap-type winding device is used. The gap-type winding is mainly based on center winding. A follower wheel is set next to the reel, and the follower roller can move back and forth. As the diameter of the reel increases, the follower roller is driven by a motor or cylinder and gradually moves away from the reel, but always maintains a fixed gap with the reel. The follower wheel keeps the cutting angle between the film and the reel basically unchanged during the winding process, so that the film has a larger wrap angle on the reel, reducing the amount of air wound into the film layer during the winding process, and when the film passes the follower wheel, the distance between the follower wheel and the winding reel is relatively close, and the traction force at each point in the lateral direction is evenly distributed, avoiding tension lines and wrinkles on the film during the winding process, further increasing the apparent quality of the winding.

[0059] Compared with the prior art, the innovations and advantages of this application are:

[0060] (1) Based on the characteristics of the printing film coating production process and the process defects of the production line, this application optimizes the frequency conversion transmission and tension control, improves the transmission system of the film coating production line, introduces the frequency converter + PLC, improves the automation level of the production line, realizes various logical relationships, has a short system response time, has a good human-machine interaction interface, and can realize the fault self-diagnosis function. Direct torque control (DTC) is adopted to achieve a high level of control accuracy of the torque and speed of the AC motor, and the static speed accuracy with a speed encoder reaches ±0.01%; the built-in PID of the frequency converter is used to achieve closed-loop control, and high-precision closed-loop control of the tension, storage rack position and floating position of the film production line is achieved, and the PID parameters can be adjusted online; the transmission motor is realized in four-quadrant operation, and the transmission point in the power generation state can feedback energy to the common DC bus for sharing by other transmission points. The whole system has high speed accuracy, small tension fluctuation, fast system response, and can quickly locate when a fault occurs. After the improvement, the running speed of the production line is stable, the tension, floating wheel position and storage rack position of each area are controlled smoothly, and the winding uniformity reaches more than 99%.

[0061] 2) This application solves the problem of high coating accuracy requirements, studies the speed distribution of 14 drag points, ensures their synchronization, makes each drag point run smoothly, and the tension fluctuations of each section are small. 6D is the main drag without an outer ring, hard given, and the other drag points follow the set speed, with an additional tension ring or position ring to ensure the film path tension. The coating station is set between 6D and 7D. The speed accuracy of this section of the film path should be less than ±0.1%, and the other drag points are less than ±1%. The tension control accuracy is less than ±1%, and the position ring accuracy is less than ±1%, which meets the requirements for precise control of transmission tension of the printing film coating production line.

[0062] 3) This application solves the problems of constant tension unwinding, tapered tension winding and the uniformity of the winding shaft, and realizes real-time roll diameter calculation, speed control, and torque control switching in the program. During winding, the PET film is the processed part and also participates in the transmission of motion and power as a rotating part. The original design of the winding length is 1800 meters. In order to improve the yield, it is increased to 3200 meters. After winding to 2400 meters, the problems of unstable tension, uneven winding, and jagged or arc-shaped edges in winding are solved. With the increase of the roll diameter, the winding tension can be decayed according to a certain rule to form a tension taper winding. The winding tension control in speed mode and the winding tension control in torque mode, as well as the roll diameter calculation problem are studied, and corresponding solutions are found to realize the electrical control of winding / unwinding, keep the tension constant or require the tension to change according to the set curve, and improve the production quality.

[0063] (4) The coating production line control improved in the present application is composed of two parts: the DCS system Freelance2000 and the transmission system AC80+ACS600. The DCS system Freelance2000 performs process control of the temperature, humidity, air volume and flow rate variables of the production line and performs analytical calculations of the trend graph of the controlled variables as well as human-computer interaction. AC80+ACS600 constitutes the transmission subsystem of Freelance2000 and is connected to Freelance2000 via the MODBUS communication protocol. The AC80PLC establishes the sequential logic control required for the production line and controls each transmission. The tension or position of each point is controlled by PID closed loop, and the speed setting and torque setting of each transmission point are calculated in combination with the synchronous speed. The PLC transmits the speed setting, torque setting and start and stop signals to the ACS600 inverter of 14 transmission points through the NDBU-95 optical fiber distribution unit and DDCS protocol communication. Each transmission point then forms a speed closed loop control through the ACS600 inverter and the speed encoder, and cooperates to establish the transmission control of the coating production line. Based on the particularity of the film, the winder is improved to solve the apparent shortcomings of uneven winding; the speed between each dragging point is synchronized, the tension is stable, and the longitudinal uniformity of the coating is consistent. The winding taper tension control of the printing film production line in the torque mode makes the winding reel look neat and the tension tightness appropriate. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a structural diagram of the transmission system of the printing film production line.

[0065] Figure 2 It is a schematic diagram of the transmission control cabinet structure.

[0066] Figure 3 It is a schematic diagram of the speed chain of a printing film production line.

[0067] Figure 4 It is a schematic diagram of closed-loop control of tension, position and speed.

[0068] Figure 5 It is a schematic diagram for setting the electrical parameters of each transmission motor.

[0069] Figure 6 It is a given diagram for setting the tension ring speed of a printing film production line.

[0070] Figure 7 This is a comparison diagram of the motor parameters of the winder before and after the update.

[0071] Figure 8 It is a schematic diagram of the adjusting wheel structure.

[0072] Fig. 9 The setting value is 71 m / min for the anti-halo winding tension of RL-100E.

[0073] Fig.10 It is the setting value of RL-100E emulsion winding tension setting 65 m / min. DETAILED DESCRIPTION

[0074] The following further describes the technical solution of the method for precise control of transmission tension of a printing film coating production line provided by the present application in conjunction with the accompanying drawings, so that those skilled in the art can better understand the present application and implement it.

[0075] This application is combined with a printing film coating production line. The control part of the production line consists of a DCS distributed control system and a transmission system. The DCS distributed control system is responsible for the process control of the production line. The transmission part consists of an AC80PLC and an ACS600 frequency converter. The AC80PLC completes the sequential logic control of the transmission system and the calculation of variables such as speed and torque of each transmission point. The frequency converter completes the drive of the transmission motor according to the speed, torque and other signals sent by the PLC.

[0076] For a production line, winding / unwinding is the focus and difficulty of control. This application combines the special requirements of printing film for winding / unwinding machines to establish a tension, torque and speed relationship model of the winding / unwinding machine to achieve constant tension control of the unwinding machine and taper tension control of the winding machine. In addition, due to the particularity of film, compared with other industries such as papermaking, the friction of the substrate is small, and the layers are easy to slide relative to each other, resulting in uneven winding, wrinkles and other drawbacks that affect the apparent quality. This application should deal with the improvement work done on the winding machine to deal with apparent drawbacks such as uneven winding.

[0077] Constructing the transmission model of the film production line, using ABB's AC drive, has the following advantages:

[0078] 1) ABB's ACS600 series inverters use direct torque control (DTC), which enables the torque and speed control accuracy of AC motors to reach a high level. The static speed accuracy with a speed encoder reaches ±0.01%;

[0079] 2) Use the built-in PID of the frequency converter to achieve closed-loop control. You can also use the PID function block of ABB's AC80PLC or Freelance2000 DCS to achieve high-precision closed-loop control of the tension of the film production line, the position of the film rack and the position of the floating Kun. The PID parameters can be adjusted online.

[0080] 3) ABB adopts multi-machine drive, that is, one power supply unit is used with multiple inverter drive units (common DC bus technology) to realize four-quadrant operation of the drive motor. The drive point in the power generation state can feed back energy to the common DC bus for sharing by other drive points.

[0081] 1. Improvement of the transmission system of printing film production line

[0082] (I) Constructing the hardware structure of the printing film production line

[0083] The production line control consists of two parts: the transmission system AC80+ACS600 and the DCS system Freelance2000. Freelance2000 controls the temperature, humidity variables and display of the operation screen of the production line. AC80+ACS600 constitute the transmission subsystem of Freelance2000, which is set to run independently to control the transmission system of the production line. AC80 provides a MODBUS communication interface to communicate with the Freelance2000 host computer, so that the transmission subsystem is integrated into the entire DCS control system. Three operation stations are set up: one engineer station ES and two operator stations OS. The engineer station can also be used as an operator station. The engineer station is set up for programming, drawing, debugging and document management of the coating process control; the operator station is set up for operation, monitoring, recording, diagnosis and trend analysis of the coating process control and coating transmission control.

[0084] AC80 (Advant controller80) sets the control center of the coating transmission control system and the frequency converter ACS600 to complete high-efficiency and high-precision transmission control, including production line sequence and interlocking settings. The whole system includes 2 AC80PLCs, which are connected to the rectifier unit and inverter through NDBU-95 optical fiber distributors. The two AC80 PLCs communicate through AF100 protocol. The basic components of the control station are as follows: Figure 1 shown.

[0085] (II) Optimization of transmission control of printing film production line

[0086] 1) Common DC bus

[0087] The entire system uses a common DC bus, separating the rectifier unit and the inverter unit of the frequency converter and installing them in their own control cabinets. The rectifier unit rectifies the AC with constant voltage and frequency into DC with constant voltage and forms a common DC bus. The inverter units are hung on the common DC bus and invert the DC with constant voltage into AC with adjustable voltage and frequency for driving the motor. A common DC bus frequency converter has one rectifier unit and can hang multiple inverter units to drive multiple motors. The common DC bus power supply is divided into a rectifier unit and a rectifier feedback unit. The rectifier feedback unit is used in systems requiring fast braking and large inertia.

[0088] The field control cabinet layout is also divided into two parts, the DCS part and the transmission control part. The transmission control cabinet is further divided into auxiliary control cabinet, rectifier cabinet, inverter cabinet, and PLC control cabinet. Figure 2 Schematic diagram of the transmission control cabinet.

[0089] 2) ACS600 inverter

[0090] The transmission control of the entire production line consists of 14 transmission points, each of which is driven by an ABB ACS600 inverter. The ACS600 inverter adopts direct torque control DTC and sets high-dynamic performance AC motor variable voltage and frequency speed regulation. In its speed loop, current feedback is used to directly control the motor's flux and torque.

[0091] The space voltage vector is directly used to calculate and control the torque and flux of the motor in the stator coordinate system; the stator magnetic field orientation is adopted, and PWM (space vector SPWM) is generated by discrete two-point regulation to directly control the switching state of the inverter to obtain high dynamic performance of the torque.

[0092] Different from vector control, each switch of direct torque control is determined by the value of flux and torque. The motor's flux and torque are calculated through the motor's stator voltage and current with the help of instantaneous space vector. Based on the difference compared with the given value, the pulse selector is optimized to determine the optimal switching position of the inverter, thereby achieving direct control of flux and torque.

[0093] 3) Encoder

[0094] A three-channel incremental rotary encoder is used as a speed feedback device. Based on photoelectric measurement, the rotary encoder outputs 2048 pulse signals through each rotation of the shaft, and there are two pulse signal outputs. From the end of the shaft, the phase pulse of channel B leads the phase pulse of channel A by 90° in the clockwise direction, and channel A leads channel B by 90° in the counterclockwise direction. Channel C is the origin signal. The pulse signal of the pulse encoder is output to the inverter NTAC-01 module. After the module sorts the pulse waveform, it is transmitted to the inverter through optical fiber for speed feedback detection.

[0095] 4) Speed ​​distribution

[0096] The speed chain of the entire production line is distributed with the 6D in front of the coating machine head as the main speed, which is hard given without tension or position loop. The rest are based on the synchronous speed plus their own tension loop or position loop PID output as the speed given, between the coating extrusion nozzle 6D and 7D, to ensure the sheet path speed and tension accuracy between 6D and 7D. Figure 3 Speed ​​chain for production line.

[0097] 5) Closed-loop control of tension, position and speed

[0098] Except for 6D, other transmission points are equipped with tension loops or position loops, and the speed and tension loops or position loops form a double closed loop system. Each transmission point is based on synchronous speed, and the tension loop or position loop is supplementary, so that each transmission point can ensure the appropriate film path tension or film storage rack (floating spoke) position based on synchronous speed. Its control block diagram is as follows: Figure 4 .

[0099] 6) Set the electrical parameters of each drive motor

[0100] Set the electrical parameters of each drive motor as follows Figure 5 The extrusion coating nozzle is between 6D and 7D. The speed and tension fluctuations of the film path in this interval directly affect the longitudinal uniformity of the coating. 6D and 7D use motor direct connection without acceleration and reduction gears.

[0101] (III) Setting the tension ring speed of the printing film production line

[0102] The tension ring speed is given as follows Figure 6 As shown, the speed setting of transmission 7D, 8D, and 9D is calculated accordingly. The synchronous speed is added with the speed correction calculated by the tension PI controller. The speed correction is limited to prevent sudden changes in speed and ensure speed stability. The speed correction is put into operation when the transmission speed increases to 95% of the synchronous speed setting value. When a stop (including emergency stop) signal is received, the speed correction is cut off and the transmission stops at a ramp according to the set deceleration time (or emergency stop deceleration time).

[0103] The speed setting of the position loop is consistent with that of the tension loop. The speed setting of transmission 3D, 4D, 5D, 10D, and 11 / 12D is calculated accordingly. The synchronous speed is added to the speed correction calculated by the position PI controller. The speed correction is limited to prevent sudden speed changes. The film rack control and floating roller control also belong to the position loop control. The difference lies in the length of the integral time. The film rack is proportional control with an integral time of 10ms, and the floating spoke is proportional integral control with an integral time of 3000ms. In addition, the film rack is also equipped with some logical controls, including roll changing, bar pressing, recovery, and overspeed operation.

[0104] 2. Improvement of tension control of unwinding / winding machine of printing film production line

[0105] (I) Improvement of tension control of winding / unwinding machine

[0106] ACS600 inverter + AC80PLC is used to realize film rewinding / unwinding tension control. 1D and 2D form a double-station unwinding device with constant tension control, and 13D and 14D form a double-station rewinding device with taper tension control.

[0107] 13D winding adopts tension closed-loop control under torque mode. The AC80PLC calculates the winding diameter, speed setting, and torque compensation. The ACS600 inverter drives the winding motor according to the speed and torque signals output by AC80, and does not calculate the speed, torque, and winding diameter itself.

[0108] The coil diameter calculation is performed through the TC block DIA_CALC. The actual coil diameter is calculated by the line speed and the actual motor speed. The specific process is to divide the actual line speed of the previous level 12D (encoder feedback speed, 12D reduction ratio and 12D wheel circumference) by the 13D motor speed, and the result is subjected to slope integral operation. The actual coil diameter of 13D is obtained by the change rate of the maximum thickness limit coil diameter (to prevent sudden changes in coil diameter caused by interference, which is impossible in the actual process).

[0109] In the curling application, the input line speed is divided by the motor speed, and the result of the quotient is subjected to ramp integration operation. The maximum thickness of the coil limits the rate of change of the coil diameter to obtain the coil diameter of the material. The coil diameter calculation is based on internal calculation and does not require additional equipment. The block also allows the use of external coil diameter sensors. The coil diameter memory program maintains the coil diameter data under any circumstances, including after power failure, reduces tension disturbances during the process of stopping or restarting the roller, and sets a resettable coil diameter data. When it is necessary to temporarily keep the coil diameter value constant, the coil diameter calculation can be paused through the digital input port.

[0110] According to the actual winding diameter of 13D, the torque setting of 13D is calculated by T = (F*D) / (2*I), T is the output torque command of the inverter, F is the tension setting command, D is the winding diameter of the reel, I is the mechanical transmission ratio, and 13D realizes closed-loop torque tension control;

[0111] In the film production line control, ABB AC80PLC calculates the torque reference through the TORQ_CTL function block. First, the input tension reference value is calculated, multiplied by the coil radius, and the static friction torque and dynamic friction torque are compensated to obtain the transmission torque reference. Second, the tension reference output of the tension regulator is processed, multiplied by the coil radius, and the corresponding torque correction is given within the specified adjustment range.

[0112] AC80 sends torque setting and start / stop related signals to ACS600 through DDCS drive bus to complete winding. AC80 is responsible for all winding calculations.

[0113] In addition, in order to quickly establish the film path tension after the roll change is restored, the winding tension can quickly reach the set value, and ensure that the tension changes according to the set curve, the torque mode tension closed-loop control in the winding system is switched only when the linear speed of the film winding motor reaches 90% of the linear speed of the previous motor. Before this, it is speed control, and the tension outer loop does not work. The given signal of speed control is composed of 13D according to the overspeed signal of the main speed plus the 12D linear speed correction amount. In this way, after the roll change is restored, the 13D linear speed can keep up with the 12D linear speed, quickly establish the 13D winding tension, and then switch to closed-loop torque tension control.

[0114] (II) Further optimization of the winder

[0115] After the film production line was renovated, further improvements were made to the winder part to address the problems exposed during the later production operation.

[0116] The film production line winder is designed to have a winding length of 1800 meters. The winding length is increased to 3200 meters, which reduces the loss of the film head and tail and increases the yield rate. The film width also exceeds the original production line design standard, with the widest width reaching 1350mm and the weight reaching 700 kg, nearly double the original 1800-meter weight. On the one hand, the winder's carrying capacity and chain transmission method can no longer meet the needs of large shaft winding. The central shaft fixing bolts of the winder are often loose, and the bearings are frequently damaged. On the other hand, the original winder tension control curve cannot meet the needs of large shaft winding, resulting in uneven winding. The apparent quality of the reel can no longer be guaranteed. In the process of sorting and cutting, huge waste is caused by uneven winding.

[0117] In view of the problems existing in the winder, the following improvements are made (such as Figure 7 shown):

[0118] Improvement 1: The steel frame of the winder is enlarged and thickened to increase the load and stability of the winder.

[0119] Improvement 2: Increase the torque of the winder: the length of the winding reel is changed from 1800 meters, diameter 450 mm, and weight 400 kg to 3200 meters, diameter 700 mm, and weight 710 kg. The motor power is increased from the original 4.0 KW to 7.5 KW, and the motor shaft is directly connected to the winding reel.

[0120] Improvement 3: Adjustment of the moment of inertia of the winder: After the winder was remodeled, it was observed that the original moment of inertia and static friction were no longer suitable for the new winder. Specifically, the tension was too low when speeding up during the winding process, and too high when decelerating. According to the diameter of the film shaft, the production line speed was multiplied by a coefficient as compensation. However, the moment of inertia was not easy to calculate. Therefore, the coefficient was gradually adjusted based on experience and trial and error to achieve an ideal state.

[0121] Improvement 4: Modify the electrical and instrument parameters of the coating transmission system, including increasing the negative pressure of 11D and 12D and adjusting the PID parameters;

[0122] Improvement 5: Adding an adjustment wheel: Adding a film adjustment rod to the winder to further solve the problem of the tangent value of the film base. In the current production process, in order to improve efficiency, the film base is generally double-stretched or even five-stretched. When winding, it is slit into two single pieces or five pieces for winding. This will inevitably cause one side of the film to be loose and the other side to be tight. This is the tangent value error. In order to solve this problem, when the film is loaded on the production line, it is stipulated that the film should be loaded with the same tightness, and the tight side is fixed to the side of the production line. On the other hand, a film adjustment rod is added to the winder. By adjusting the adjustment handle, the tightness of the left and right sides of the winder film path can be manually fine-tuned. Figure 8 It is a schematic diagram of the adjusting wheel structure.

[0123] Improvement 6: Adding a sheet edge embossing device: Increase the sheet edge friction and reduce the relative sliding between sheet layers. During the winding process, the tension changes continuously, which will cause the internal stress of the wound reel to change. During the storage process, the release of tension will also cause the reel to deform. By adding an embossing wheel, hot-pressing patterns on both sides of the sheet path, increasing the sheet edge friction, reducing or avoiding reel deformation;

[0124] Improvement seven: Change the winding tension curve: Analyze the factors that cause uneven winding, including two major factors, the film's own characteristics and the winder's performance. The dominant factors in the film's own characteristics are the film's friction coefficient and the film base tangent value. Regarding the friction coefficient, the larger the friction coefficient, the easier it is to wind evenly. Anti-halo film has better winding uniformity than emulsion film, and the film base tangent value should also be controlled within ±1mm / 3m.

[0125] The winder transformation includes mechanical and electrical transformation. Mechanically, the balance of the winder and the front guide wheel of the winder, the load capacity and stability of the overall structure of the winder are set; electrically, the overall speed and tension control accuracy of the winder, the motor transmission torque and the winding tension curve are set.

[0126] After the transformation, the winder has met the requirements mechanically, and the original control speed and accuracy can also meet the requirements electrically. The motor is changed from 4KW to 7.5KW. After deceleration, the torque is increased from the original 198.9NM to 425NM. In fact, the torque required for the winder is not large. According to the initial tension of 43KG and the final tension of 32KG, the roll diameter is 700mm when it is received at 3200 meters. The maximum torque required is about 112NM. In addition to the transmission mechanical loss, the torque of the winder can fully meet the winding needs.

[0127] In this case, the factor affecting the uniformity of winding is the problem of inappropriate winding tension curve. Before the transformation, the tension curve of the winding machine was also adjusted due to uneven winding, from the initial oblique line (only the initial tension and slope can be adjusted) to arc winding.

[0128] F=F 0 [1-K×(1-D 0 / D)]

[0129] F is the actual winding tension, F 0 is the initial tension of winding, K is the tension taper coefficient, D 0 is the initial coil diameter, and D is the current coil diameter.

[0130] This winding curve can only adjust the initial tension and tension taper coefficient. The winding situation is still not ideal after adjustment. The above curve can only meet the requirements of low vehicle speed, small roll diameter winding, large shaft winding, especially winding emulsion films with silicone oil. It will deviate after 2300 meters. On the film production line, it will deviate to the south all the time. In severe cases, it will deviate by 5-10 cm and cannot be packaged at all.

[0131] In view of the above two tension curves, after determining the initial tension and tension taper coefficient, the entire curve is determined and cannot be adjusted locally. Now it is changed to a tension segmented curve. According to the actual situation, the entire winding tension is divided into 5 segments, and each segment corresponds to a decay slope. Add the following to the central control operator station screen:

[0132] The tension calculation in the program is:

[0133] Section 1 F=F 0 -(D-200) / (D 1 -200)×F 0 ×K 1 ;

[0134] Paragraph 2: F = (F 0 - F 0 K 1 ) - (D - D 1 ) / (D 2 - D 1 ) × F 0 × (K 2 - K 1 );

[0135] Paragraph 3: F = (F 0 - F 0 K 2 ) - (D - D 2 ) / (D 3 - D 2 ) × F 0 × (K 3 - K 2 )

[0136] Paragraph 4: F = (F 0 - F 0 K 3 ) - (D - D 3 ) / (D 4 - D 3 ) × F 0 × (K 4 - K 3 )

[0137] Paragraph 5: F = (F 0 - F 0 K 4 ) - (D - D 4 ) / (D 5 - D 4 ) × F 0 × (K 5 - K 4 )

[0138] Where: F is the real-time set tension (tension set value when the coil diameter is D), F 0 is the initial tension value, D is the real-time coil diameter (obtained by program calculation), K 1 , K 2 , K 3 , K 4 , K 5 are the slopes of the 1st - 5th segments, D 1 , D 2 , D 3 , D 4 , D 5 are the coil diameters of the 1st - 5th segments.

[0139] The operator divides the winding into sections and inputs the corresponding winding tension according to the specific situation. If the winding deviates between sections 4 and 5, the slope of section 5 should be adjusted appropriately without affecting the previous winding situation. If indentation appears on the axis, the initial tension should be reduced and the slope of section 1 should be increased.

[0140] Fig. 9 and Fig.10 It is the setting value of winding tension for two types of films.

[0141] Improvement 8: Adding a gap-type winding device

[0142] For high-speed, wide-width winders, the neatness of the two sides of the reel is further increased by using a gap winding device. The gap winding is mainly based on center winding. A follower wheel is set next to the reel. The follower roller can move back and forth. As the diameter of the reel increases, the follower roller is driven by a motor or cylinder to gradually move away from the reel, but always maintains a fixed gap with the reel (some also press the reel). The follower wheel keeps the cutting angle between the film and the reel basically unchanged during the winding process, so that the film has a larger wrap angle on the reel, reducing the amount of air wound into the film layer during the winding process, and when the film passes the follower wheel, the distance between the follower wheel and the winding reel is relatively close, and the traction force at each point in the lateral direction is evenly distributed, avoiding tension lines and wrinkles on the film during the winding process, further increasing the apparent quality of the winding.

Claims

1. A method for precisely controlling transmission tension of a printing film coating production line, characterized in that: Based on the production process characteristics of printing film coating and the process defects of the production line, the variable frequency drive and tension control are optimized, and the transmission system of the film coating production line is improved; The improved coating production line control consists of two parts: DCS system Freelance2000 and transmission system AC80+ACS600. The DCS system Freelance2000 performs process control of production line temperature, humidity, air volume and flow rate variables, analytical calculation of controlled variable trend charts and human-computer interaction. AC80+ACS600 constitutes the transmission subsystem of Freelance2000 and is connected to Freelance2000 through MODBUS communication protocol. AC80PLC establishes the sequential logic control required by the production line, performs PID closed-loop control on the tension or position of each transmission point, and calculates the speed setting and torque setting of each transmission point in combination with the synchronous speed. PLC transmits speed setting, torque setting and start-stop signals to the ACS600 inverter of 14 transmission points through NDBU-95 optical fiber distribution unit and DDCS protocol communication. Each transmission point then forms a speed closed-loop control through the ACS600 inverter and speed encoder, and cooperates to establish the transmission control of the coating production line. Based on the particularity of the film, the winder is improved to solve the apparent problem of uneven winding. 1) Improvement of the transmission system of the printing film production line, including: building the hardware structure of the printing film production line, optimizing the transmission control of the printing film production line, and setting the speed of the tension ring of the printing film production line; 2) Improvement of tension control of unwinding / winding machine of printing film production line, including: improvement of tension control of unwinding / winding machine and further optimization of winder; In combination with the special requirements of printing film for winder / unwinder, a tension, torque and speed relationship model of winder / unwinder is established to realize constant tension control of unwinder and taper tension control of winder.

2. The method for precise control of transmission tension of a printing film coating production line according to claim 1, characterized in that: Construct the hardware structure of the printing film production line: set up three operation stations: one engineer station ES and two operator stations OS. The engineer station can also be used as an operator station. The engineer station is set up for programming, drawing, debugging and document management of coating process control; the operator station is set up for operation, monitoring, recording, diagnosis and trend analysis of coating process control and coating transmission control; The control center of the AC80 coating drive control system and the frequency converter ACS600 jointly complete high-efficiency and high-precision drive control, including production line sequence and interlocking settings. The entire system includes two AC80PLCs, which are connected to the rectifier unit and inverter through NDBU-95 optical fiber distributors respectively. The two AC80 PLCs communicate with each other through the AF100 protocol.

3. The method for precise control of transmission tension of a printing film coating production line according to claim 1, characterized in that: Optimization of transmission control for printing film production line: 1) Public DC bus: The whole system adopts a public DC bus, and the rectifier unit and inverter unit of the inverter are separated and installed in their own control cabinets. The rectifier unit rectifies the AC with constant voltage and frequency into DC with constant voltage, and forms a public DC bus. The inverter units are hung on the public DC bus, and the DC with constant voltage is inverted into AC with adjustable voltage and frequency, which is used to drive the motor. The public DC bus inverter is equipped with one rectifier unit and can hang multiple inverter units to drive multiple motors. The public DC bus power supply mode is divided into rectifier unit and rectifier feedback unit. The rectifier feedback unit is used in systems requiring fast braking and large inertia; The layout of the field control cabinet is also divided into two parts, the DCS part and the transmission control part. The transmission control cabinet is further divided into auxiliary control cabinet, rectifier cabinet, inverter cabinet, and PLC control cabinet. 2) ACS600 inverter: The entire production line drive control consists of 14 drive points, each of which is driven by an ABB ACS600 inverter. The ACS600 inverter uses direct torque control DTC and sets a high-dynamic performance AC motor variable voltage and frequency speed regulation. In its speed loop, it uses current feedback to directly control the motor's magnetic flux and torque. Directly use the space voltage vector to calculate and control the torque and flux of the motor in the stator coordinate system; adopt the stator magnetic field orientation, with the help of discrete two-point regulation to generate PWM to directly control the switching state of the inverter optimally, and obtain high dynamic performance of the torque; Each switch of direct torque control is determined by the value of magnetic flux and torque. The motor flux and torque are calculated by the instantaneous space vector through the motor stator voltage and current. The pulse selector is optimized to determine the best switch position of the inverter based on the difference compared with the given value, thus realizing direct control of magnetic flux and torque. 3) Encoder: A three-channel incremental rotary encoder is used as a speed feedback device. Based on photoelectric measurement, the rotary encoder outputs 2048 pulse signals through each rotation of the shaft, and there are two pulse signal outputs. From the end of the shaft, in the clockwise direction, the channel B phase pulse leads the channel A phase pulse by 90°, and in the counterclockwise direction, the channel A leads the channel B by 90°. Channel C is the origin signal. The pulse signal of the pulse encoder is output to the inverter NTAC-01 module. After the module sorts the pulse waveform, it is transmitted to the inverter through optical fiber for speed feedback detection; 4) Speed ​​distribution: The speed chain of the entire production line is distributed with the 6D in front of the coating head as the main speed, which is hard given without tension or position loop. The rest are based on the synchronous speed and add their own tension loop or position loop PID output as the speed given, between the coating extrusion nozzle 6D and 7D, to ensure the sheet path speed and tension accuracy between 6D and 7D; 5) Tension, position, speed closed-loop control: except for 6D, other transmission points are equipped with tension loop or position loop, and the speed and tension loop or position loop constitute a double closed-loop system. Each transmission point is mainly based on synchronous speed, and the tension loop or position loop is supplementary, so that each transmission point can ensure the appropriate film path tension or film storage rack position on the basis of synchronous speed; 6) Set the electrical parameters of each transmission motor: the extrusion coating nozzle is between 6D and 7D. The speed and tension fluctuations of the film path in this interval directly affect the longitudinal uniformity of the coating. 6D and 7D adopt the motor direct connection method.

4. The method for precise control of transmission tension of a printing film coating production line according to claim 1, characterized in that: Setting the speed of the tension ring of the printing film production line: the given speeds of the transmission 7D, 8D, and 9D are calculated accordingly, and the synchronous speed is added with the speed correction calculated by the tension PI controller. The speed correction is limited to prevent sudden changes in speed and ensure speed stability. The speed correction is put into operation when the transmission speed increases to 95% of the given synchronous speed. When the stop signal is received, the speed correction is cut off and the transmission stops at the set deceleration time ramp. The speed setting of the position loop is consistent with that of the tension loop. The speed setting of transmission 3D, 4D, 5D, 10D, and 11 / 12D is calculated accordingly. The synchronous speed is added to the speed correction calculated by the position PI controller. The speed correction is limited to prevent sudden speed changes. The film rack control and floating roller control also belong to the position loop control. The difference lies in the length of the integral time. The film rack is proportional control with an integral time of 10ms, and the floating spoke is proportional integral control with an integral time of 3000ms. In addition, the film rack is also equipped with some logical controls, including roll changing, bar pressing, recovery, and overspeed operation.

5. The method for precise control of transmission tension of a printing film coating production line according to claim 1, characterized in that: Improvement of tension control of winding / unwinding machine: Adopt ACS600 inverter + AC80PLC to realize tension control of film winding / unwinding. 1D and 2D form a double-station unwinding device with constant tension control. 13D and 14D form a double-station winding device with taper tension control. 13D winding adopts tension closed-loop control in torque mode. The AC80PLC calculates the winding diameter, speed setting, and torque compensation. The ACS600 inverter drives the winding motor according to the speed and torque signals output by AC80, and does not calculate the speed, torque, and winding diameter. The coil diameter calculation is performed through the TC block DIA_CALC. The actual coil diameter is calculated by the line speed and the actual motor speed. The specific process is to divide the actual line speed of the previous level 12D by the motor speed of 13D, and the result is obtained by slope integration operation. The actual coil diameter of 13D is obtained by the change rate of the coil diameter limited by the maximum thickness of the coil; In the curling application, the input line speed is divided by the motor speed, and the result of the quotient is calculated by the slope integration. The maximum thickness of the coil limits the change rate of the coil diameter to obtain the coil diameter of the material. The coil diameter calculation is based on internal calculation and does not require additional equipment. The block also allows the use of external coil diameter sensors. The coil diameter memory program maintains the coil diameter data under any circumstances, including after power failure, reduces tension disturbance during the process of stopping or restarting the roller, and sets a resettable coil diameter data. When it is necessary to temporarily keep the coil diameter value constant, the coil diameter calculation can be paused through the digital input port; According to the actual winding diameter of 13D, the torque setting of 13D is calculated by T = (F*D) / (2*I), T is the output torque command of the inverter, F is the tension setting command, D is the winding diameter of the reel, I is the mechanical transmission ratio, and 13D realizes closed-loop torque tension control; In the film production line control, ABB AC80PLC calculates the torque setting through the TORQ_CTL function block. First, the input tension setting value is calculated, multiplied by the coil radius, and the static friction torque and dynamic friction torque are compensated to obtain the transmission torque setting. Second, the tension setting output of the tension regulator is processed and multiplied by the coil radius to give the correction amount for the torque within the specified adjustment range. AC80 sends torque setting and start / stop and other related signals to ACS600 through DDCS drive bus to complete winding. AC80 is responsible for all winding calculations.

6. The method for precise control of transmission tension of a printing film coating production line according to claim 1, characterized in that: Further optimization of the winder: Improvement 1: The steel frame of the winder is enlarged and thickened to increase the load and stability of the winder. Improvement 2: Increase the torque of the winder: the length of the winding reel is changed from 1800 meters, diameter 450 mm, and weight 400 kg to 3200 meters, diameter 700 mm, and weight 710 kg. The motor power is increased from the original 4.0 KW to 7.5 KW, and the motor shaft is directly connected to the winding reel. Improvement 3: Adjustment of the moment of inertia of the winder: After the winder is modified, the moment of inertia and static friction coefficient are gradually adjusted to an ideal state based on experience and trial and error; Improvement 4: Modify the electrical and instrument parameters of the coating transmission system, including increasing the negative pressure of 11D and 12D and adjusting the PID parameters.

7. The method for precise control of transmission tension of a printing film coating production line according to claim 1, characterized in that: Further optimization of the winder: Improvement 5: Adding an adjustment wheel: Adding a film adjustment rod to the winder to further solve the problem of the film base tangent value. When loading the film on the production line, it is required to load the film with the same tightness, and the tight side is fixed to the side of the production line. On the other hand, adding a film adjustment rod to the winder, by adjusting the adjustment handle, manually fine-tuning the tightness of the film path of the winder on the left and right; Improvement 6: Adding an embossing device on the edge of the sheet: Increase the friction on the edge of the sheet and reduce the relative sliding between the sheet layers. By adding an embossing wheel, hot-press patterns on both sides of the sheet path to increase the friction on the edge of the sheet and reduce or avoid deformation of the reel.

8. The method for precise control of transmission tension of a printing film coating production line according to claim 1, characterized in that: Further optimization of the winder: Improvement 7: Change the winding tension curve: There are two major factors that cause uneven winding: the film's own characteristics and the winding machine's performance. The dominant factors in the film's own characteristics are the film's friction coefficient and the film base tangent value. Regarding the friction coefficient, the larger the friction coefficient, the easier it is to wind evenly. The anti-halation film has better winding evenness than the emulsion film, and the film base tangent value should also be controlled within ±1mm / 3m. After determining the initial tension and tension taper coefficient, the entire curve is determined and changed to a tension segmented curve. The entire winding tension is divided into 5 segments according to the actual situation. Each segment corresponds to a decay slope. The following is added to the central control operator station screen: The tension calculation in the program is: The first segment F = F0-(D-200) / (D1-200)×F0×K1; The second segment F = (F0-F0K1)-(D-D1) / (D2-D1)×F0×(K2-K1); The third segment F = (F0-F0K2)-(D-D2) / (D3-D2)×F0×(K3-K2) Section 4 F=(F0-F0K3)-(D-D3) / (D4-D3)×F0×(K4-K3) The fifth segment F = (F0-F0K4) - (D-D4) / (D5-D4) × F0 × (K5-K4) Among them: F is the real-time set tension, F0 is the initial tension value, D is the real-time roll diameter, K1, K2, K3, K4, K5 are the slopes of sections 1-5, and D1, D2, D3, D4, D5 are the roll diameters of sections 1-5; The operator divides the winding into sections and inputs the corresponding winding tension according to the specific situation. If the winding deviates between sections 4 and 5, the slope of section 5 should be adjusted appropriately without affecting the previous winding situation. If indentation appears on the axis, the initial tension should be reduced and the slope of section 1 should be increased.

9. The method for precise control of transmission tension of a printing film coating production line according to claim 1, characterized in that: Further optimization of the winder: Improvement 8: Adding a gap-type winding device: For high-speed, wide-width winders, the neatness of the two sides of the reel is further increased, and a gap-type winding device is used. The gap-type winding is mainly based on center winding. A follower wheel is set next to the reel, and the follower roller can move back and forth. As the diameter of the reel increases, the follower roller is driven by a motor or cylinder and gradually moves away from the reel, but always maintains a fixed gap with the reel. The follower wheel keeps the cutting angle between the film and the reel basically unchanged during the winding process, so that the film has a larger wrap angle on the reel, reducing the amount of air wound into the film layer during the winding process, and when the film passes the follower wheel, the distance between the follower wheel and the winding reel is relatively close, and the traction force at each point in the lateral direction is evenly distributed, avoiding tension lines and wrinkles on the film during the winding process, further increasing the apparent quality of the winding.

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