Resin film conveying machine, its control method, and resin film manufacturing device

Abstract

To provide a resin film carrying machine capable of automatically adjusting a rotational speed of a roll.SOLUTION: In a resin film carrying machine according to one embodiment, on the basis of a rotational speed of a first driving source for driving a first roll, and an index for indicating a state of a resin film in a second roll adjacently arranged in a subsequent stage of the first roll, a rotational speed of a second driving source for driving the second roll is feed-back controlled.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a resin film conveying machine, a control method thereof, and a resin film manufacturing apparatus. [Background technology]

[0002] The resin film manufacturing apparatus disclosed in Patent Document 1 is equipped with a resin film conveying machine (longitudinal stretching machine or the like) including a plurality of rolls for conveying an extruded resin film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-230163 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors have found the following problems in a resin film conveying machine including a plurality of rolls for conveying an extruded resin film. For example, when increasing the rotation speed of the rolls to the production speed at the start of resin film production, an operator manually adjusts the rotation speed of the rolls while visually observing the state of the resin film. Because this type of adjustment work requires skill, there are problems such as variations in the adjustment time depending on the operator's level of proficiency. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0005] In one embodiment of the resin film conveying machine, the rotational speed of a second drive source that drives a second roll is feedback controlled based on the rotational speed of a first drive source that drives the first roll and an index that indicates the state of the resin film on a second roll that is arranged adjacent to and downstream of the first roll.

[0006] In one embodiment of a control method for a resin film conveying machine, the rotational speed of a second drive source that drives a second roll is feedback controlled based on the rotational speed of a first drive source that drives the first roll and an index that indicates the state of the resin film on a second roll that is arranged adjacent to and downstream of the first roll.

[0007] In one embodiment of a resin film manufacturing apparatus, the rotational speed of a second drive source that drives a second roll is feedback controlled based on the rotational speed of a first drive source that drives a first roll and an index that indicates the state of the resin film on a second roll that is arranged adjacent to and downstream of the first roll. [Effects of the Invention]

[0008] According to the embodiment, it is possible to provide a resin film transporting machine capable of automatically adjusting the rotation speed of the roll. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view showing the overall configuration of a resin film manufacturing apparatus according to a first embodiment. [Figure 2] 1 is a schematic cross-sectional view showing the overall configuration of a resin film manufacturing apparatus according to a first embodiment. [Figure 3] FIG. 2 is a block diagram showing the configuration of a control unit 700 according to a comparative example. [Figure 4] FIG. 2 is a block diagram showing the configuration of a control unit 70 according to the first embodiment. [Figure 5] 4 is a flowchart showing a method for controlling a resin film conveying machine according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Specific embodiments will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments. For clarity of explanation, the following description and drawings have been simplified as appropriate.

[0011] (First embodiment) <Overall configuration of resin film manufacturing equipment> First, the overall configuration of a resin film manufacturing apparatus including a resin film conveying device according to a first embodiment will be described with reference to Figures 1 and 2. Figure 1 is a schematic perspective view showing the overall configuration of the resin film manufacturing apparatus according to the first embodiment. Figure 2 is a schematic cross-sectional view showing the overall configuration of the resin film manufacturing apparatus according to the first embodiment.

[0012] It should be noted that the right-handed xyz Cartesian coordinate system shown in Figure 1 and other drawings is a matter of convenience for explaining the positional relationships of the components. Normally, the positive direction of the z axis is vertically upward, and the xy plane is the horizontal plane, which is common among the drawings. In this specification, the term "resin film" also includes a resin sheet.

[0013] As shown in Figures 1 and 2, the resin film manufacturing apparatus according to the first embodiment includes an extruder 10, a T-die 20, a cooler 30, a longitudinal stretching machine 40, a transverse stretching machine 50, a winder 60, and a control unit 70. The resin film manufacturing apparatus according to the first embodiment is an extrusion molding type resin film manufacturing apparatus that extrudes a film-like molten resin 82a from a gap between the lips of the T-die 20 connected to the extruder 10. Note that the control unit 70 is omitted in Figure 1, and the transverse stretching machine 50 is omitted in Figure 2.

[0014] The extruder 10 shown in Figures 1 and 2 is a screw-type extruder. As shown in Figure 2, the extruder 10 has a cylinder 11 extending in the x-axis direction and a screw 12 extending in the x-axis direction housed inside the cylinder 11. A hopper 13 is provided above the end of the cylinder 11 on the negative x-axis direction side for introducing resin pellets 81, which are the raw material for a resin film 83.

[0015] Resin pellets 81 supplied from hopper 13 are transported from the base to the tip of rotating screw 12, i.e., in the positive direction of the x-axis. Inside cylinder 11, resin pellets 81 are heated and sheared by rotating screw 12, melting them and turning into molten resin 82.

[0016] Although not shown, the screw 12 is connected to a motor as a drive source via a reducer, for example. In addition, a heater for heating the inside of the cylinder 11 is provided on the outer peripheral surface of the cylinder 11 over almost the entire area in the longitudinal direction, and the resin pellets 81 put into the cylinder 11 are heated.

[0017] As shown in FIGS. 1 and 2, the T-die 20 is connected to the lower side of the tip end (the end on the positive x-axis direction) of the extruder 10. A film-like molten resin 82a is extruded downward (in the negative z-axis direction) through a gap in a lip located at the lower end of the T-die 20. The lip spacing of the T-die 20 can be adjusted. The lip spacing of the T-die 20 can be adjusted at multiple locations along the longitudinal direction of the lip (in the y-axis direction) so that the thickness of the produced resin film 83 in the width direction (in the y-axis direction) is uniform.

[0018] As shown in FIGS. 1 and 2, the cooling machine 30 includes cooling rolls CR1 to CR4. The cooling roll CR1 cools the film-like molten resin 82a extruded from the T-die 20, and delivers the resin film 83 formed by solidifying the film-like molten resin 82a to the cooling roll CR2. The cooling roll CR1 is also called a casting roll.

[0019] 1 and 2, the cooling rolls CR2 to CR4 transport the resin film 83 in this order while cooling it. Each of the cooling rolls CR1 to CR4 may be a driving roll driven by a driving source (not shown). The driving source is, for example, a variable speed motor such as a servo motor.

[0020] Each of the cooling rolls CR1 to CR4 may be provided with a cooling mechanism for cooling the resin film 83. Also, each of the cooling rolls CR1 to CR4 may be provided with a heating mechanism for heating the resin film 83. Furthermore, the cooler 30 includes a plurality of drive rolls for transporting the resin film 83, and therefore can be one form of the resin film transport device according to this embodiment.

[0021] As shown in Fig. 1, the longitudinal stretching machine 40 stretches the resin film 83 carried out from the cooling machine 30 in the longitudinal direction while transporting the same. The longitudinal stretching machine 40 illustrated in Figs. 1 and 2 includes 11 rolls R1 to R11. Each of the rolls R1 to R11 is a driving roll driven by a driving source (not shown). The driving source is, for example, a variable speed motor such as a servo motor. The longitudinal stretching machine 40 is one form of the resin film transporting machine according to this embodiment.

[0022] The longitudinal stretching machine 40 only needs to be equipped with a plurality of drive rolls for transporting the resin film 83, and the number and arrangement of the drive rolls equipped in the longitudinal stretching machine 40 are determined appropriately. Each of the rolls R1 to R11 may be provided with at least one of a cooling mechanism for cooling the resin film 83 and a heating mechanism for heating the resin film 83. Furthermore, the longitudinal stretching machine 40 may be provided with one or more nip rolls for pressing the resin film 83 against any of the rolls R1 to R11. The nip rolls are not drive rolls.

[0023] 1, the transverse stretching machine 50 stretches the resin film 83 delivered from the longitudinal stretching machine 40 in its width direction (y-axis direction). More specifically, the transverse stretching machine 50 includes a pair of rails RL1 and RL2. A large number of clips (not shown) are slidably arranged in parallel along the entire length of the rails RL1 and RL2.

[0024] In Fig. 1, the arrows shown on the rails RL1 and RL2 indicate the movement direction of the clips. As shown in Fig. 1, the rails RL1 and RL2 have a loop structure with an outgoing path along which the clips move in the conveying direction of the resin film 83 (positive direction of the x-axis) and a returning path along which the clips move in the opposite direction (negative direction of the x-axis). That is, in the transverse stretching machine 50, the clips revolve along the rails RL1 and RL2 having the loop structure. As shown in FIG. 1, the rails RL1 and RL2 have a symmetrical configuration with respect to a plane parallel to the xz plane.

[0025] 1, the rails RL1 and RL2 have an outgoing path extending in the conveyance direction (positive direction of the x-axis) and a returning path extending in the opposite direction (negative direction of the x-axis) that are arranged substantially parallel to each other. The returning path of rail RL1 is arranged on the outer side in the width direction of resin film 83 (negative direction of the y-axis). The returning path of rail RL2 is also arranged on the outer side in the width direction of resin film 83 (positive direction of the y-axis).

[0026] As shown in Figure 1, the outgoing paths of rails RL1 and RL2 have a pair of parallel portions parallel to the x-axis at both ends in the longitudinal direction (x-axis direction), and an inclined portion inclined in the y-axis direction between the parallel portions. The inclined portion of rail RL1 is inclined in the negative direction of the y-axis, and the inclined portion of rail RL2 is inclined in the positive direction of the y-axis. That is, in the inclined portions of the outgoing paths of rails RL1 and RL2, the distance between rails RL1 and RL2 in the y-axis direction increases as the rails progress in the positive direction of the x-axis.

[0027] 1, in the portions where the clips come into contact with the resin film 83, the clips grip both ends of the resin film 83 in the width direction (y-axis direction) and move in the positive x-axis direction along the rails RL1 and RL2. Therefore, as shown in FIG. 1, in the oblique portions of the outgoing passes of the rails RL1 and RL2, the resin film 83 is stretched in the width direction (y-axis direction) while being transported in the positive x-axis direction. On the other hand, in the parallel portions of the outgoing passes of the rails RL1 and RL2, the resin film 83 is only transported in the positive x-axis direction and is not stretched in the width direction (y-axis direction).

[0028] In the rails RL1 and RL2 shown in FIG. 1, in the portions that are not in contact with the resin film 83, the clips do not grip the resin film 83 but move along the rails RL1 and RL2. 1 has a drive source that drives clips for transporting the resin film 83. The drive source is, for example, a variable speed motor such as a servo motor. The transverse stretching machine 50 can be one form of the resin film transport machine according to this embodiment.

[0029] The resin film 83 discharged from the transverse stretching machine 50 is taken up by the winding machine 60. The winding machine 60 is a drive roll driven by a drive source (not shown). The winding machine 60 may include a plurality of drive rolls driven by a drive source. In this case, the winding machine 60 can be one form of the resin film transport machine according to this embodiment.

[0030] 2 controls the rotation speeds of the drive sources that drive the rolls R1 to R11 included in the longitudinal stretching machine 40, which is the resin film conveying machine according to this embodiment. That is, the control unit 70 controls the rotation speeds of the rolls R1 to R11.

[0031] Here, the control unit 70 determines the rotation speed of the drive source (e.g., second drive source) of the roll (e.g., second roll) R2 arranged adjacent to the roll (e.g., first roll) R1 based on the rotation speed of the drive source (e.g., first drive source) that drives the roll (e.g., first roll) R1. Furthermore, the control unit 70 feedback-controls the rotation speed of the drive source of the roll R2 based on an index indicating the state of the resin film 83 on the roll R2.

[0032] Similarly, the control unit 70 determines the rotation speed of the drive source (e.g., third drive source) of a roll (e.g., third roll) R3 disposed adjacently and downstream of the roll R2 based on the rotation speed of the drive source of the roll R2. Furthermore, the control unit 70 feedback-controls the rotation speed of the drive source of the roll R3 based on an index indicating the state of the resin film 83 on the roll R3. The rotation speeds of the drive sources that drive the other rolls R4 to R11 are controlled in the same manner. The configuration and operation of the control unit 70 will be described in more detail later.

[0033] The control unit 70 may feedback-control only some of the rolls R1 to R11 that the longitudinal stretching machine 40 has. The control unit 70 may also control the rotation speeds of the driving sources that drive the cooling rolls CR1 to CR4 provided in the cooler 30, the transverse stretching machine 50, and the winding machine 60. That is, the control unit 70 may control the rotation speeds of the cooling rolls CR1 to CR4 and the winding machine 60 and the conveying speed of the resin film 83 by the transverse stretching machine 50.

[0034] In this way, in the resin film conveying machine according to this embodiment (i.e., the longitudinal stretching machine 40), the rotation speed of the drive source of the roll to be controlled is feedback controlled based on an index indicating the state of the resin film 83 on the roll. That is, in the resin film conveying machine according to this embodiment, the rotation speed of the roll (i.e., the conveying speed of the resin film 83) can be automatically adjusted. Therefore, for example, there is no need to visually observe the state of the resin film 83, and there is no need for an operator to manually adjust the rotation speed of the roll.

[0035] As will be described later, an indicator showing the state of the resin film 83 on the roll is, for example, the torque of a motor that drives the roll. However, the indicator is not limited to this, and the tension of the resin film 83 may be detected using ultrasound, an image, or the like. Furthermore, the resin film conveying machine according to this embodiment is not limited to the longitudinal stretching machine 40. As described above, the cooling machine 30, the transverse stretching machine 50, or the winding machine 60 may be one aspect of the resin film conveying machine according to this embodiment.

[0036] For example, when the chiller 30 is one aspect of the resin film conveying device according to this embodiment, the control unit 70 may determine the rotation speed of the drive source of the cooling roll CR2 disposed adjacent to and downstream of the cooling roll CR1 based on the rotation speed of the drive source of the cooling roll CR1. The control unit 70 may then feedback-control the rotation speed of the drive source of the cooling roll CR2 based on an index indicating the state of the resin film 83 on the cooling roll CR2.

[0037] Similarly, the control unit 70 may determine the rotation speed of the drive source of the cooling roll CR3, which is disposed adjacent to and downstream of the cooling roll CR2, based on the rotation speed of the drive source of the cooling roll CR2. The control unit 70 may then feedback-control the rotation speed of the drive source of the cooling roll CR3 based on an index indicating the state of the resin film 83 on the cooling roll CR3. The rotation speed of the drive source that drives the cooling roll CR4 may also be controlled in a similar manner.

[0038] <Configuration of control unit 700 according to comparative example> Here, the configuration of the control unit 700 in the resin film conveying machine (that is, the longitudinal stretching machine 40) according to the comparative example will be described with reference to Fig. 3. Fig. 3 is a block diagram showing the configuration of the control unit 700 according to the comparative example.

[0039] As shown in FIG. 3, the control unit 700 includes speed setting units 71, 72, 73, . . . that set the rotation speeds of the rolls R1 to R11 included in the longitudinal stretching machine 40 shown in FIGS. The resin film manufacturing apparatus including the resin film transport device according to the comparative example has the same overall configuration as the resin film manufacturing apparatus according to the first embodiment shown in FIGS.

[0040] As shown in Figure 3, roll R1 is driven by motor MT1, which is driven by motor drive circuit MDC1. Roll R2 is driven by motor MT2, which is driven by motor drive circuit MDC2. Roll R3 is driven by motor MT3, which is driven by motor drive circuit MDC3. The other rolls are driven in the same way.

[0041] As shown in FIG. 3, a speed setting unit 71 outputs a set value vm1_sv of the rotation speed of the motor MT1 to the motor drive circuit MDC1. On the other hand, the measured value vm1_pv of the rotation speed of the motor MT1 detected by the motor drive circuit MDC1 is output from the motor drive circuit MDC1 to the speed setting section 72 of the rear roll R2.

[0042] The speed setting unit 72 multiplies the measured value vm1_pv of the rotational speed of the motor MT1 acquired from the motor drive circuit MDC1 by the draw ratio dr2 to calculate the set value vm2_sv (=vm1_pv×dr2) of the rotational speed of the motor MT2. In other words, the speed setting unit 72 is a multiplication circuit.

[0043] Here, the draw ratio dr2 is the ratio of the rotational speed of motor MT2 to the rotational speed of motor MT1, and is input by the operator. That is, the set value vm2_sv of the rotational speed of motor MT2 is determined based on the measured value vm1_pv of the rotational speed of motor MT1.

[0044] The speed setting unit 72 then outputs the calculated set value vm2_sv of the rotation speed of the motor MT2 to the motor drive circuit MDC2. On the other hand, the measured value vm2_pv of the rotation speed of the motor MT2 detected by the motor drive circuit MDC2 is output from the motor drive circuit MDC2 to the speed setting section 73 of the rear roll R3.

[0045] Similarly, the speed setting unit 73 multiplies the measured value vm2_pv of the rotational speed of the motor MT2 acquired from the motor drive circuit MDC2 by the draw ratio dr3 to calculate the set value vm3_sv (=vm2_pv×dr3) of the rotational speed of the motor MT3. In other words, like the speed setting unit 72, the speed setting unit 73 is also a multiplication circuit.

[0046] Here, the draw ratio dr3 is the ratio of the rotational speed of motor MT3 to the rotational speed of motor MT2, and is input by the operator. That is, the set value vm3_sv of the rotational speed of motor MT3 is determined based on the measured value vm2_pv of the rotational speed of motor MT2.

[0047] The speed setting unit 73 then outputs the calculated set value vm3_sv of the rotation speed of the motor MT3 to the motor drive circuit MDC3. On the other hand, the measured value vm3_pv of the rotation speed of the motor MT3 detected by the motor drive circuit MDC3 is output from the motor drive circuit MDC3 to a speed setting section (not shown) of the rear roll R4. The speed setting units for setting the rotation speeds of the other rolls are similar to the speed setting units 72 and 73 .

[0048] Here, a specific example of speed setting will be described. Assume that the measured value vm1_pv of the rotational speed of the motor MT1 obtained from the motor drive circuit MDC1 is 10 m / min.

[0049] Here, it is assumed that the draw ratio dr2 input to the speed setting unit 72 is 300%, and the draw ratio dr3 input to the speed setting unit 73 is 100%. In this case, the set value vm2_sv of the rotational speed of the motor MT2 output from the speed setting unit 72 to the motor drive circuit MDC2 is 30 m / min (= 10 m / min × 3).

[0050] If the set value vm2_sv of the rotational speed of motor MT2 is equal to the measured value vm2_pv, the set value vm3_sv of the rotational speed of motor MT3 output from the speed setting unit 73 to the motor drive circuit MDC3 is 30 m / min (= 30 m / min × 1). Here, when the draw ratio exceeds 100%, the resin film 83 is stretched in the longitudinal direction.

[0051] On the other hand, suppose that the draw ratio dr2 input to the speed setting unit 72 is 80% and the draw ratio dr3 input to the speed setting unit 73 is 50%. In this case, the set value vm2_sv of the rotational speed of the motor MT2 output from the speed setting unit 72 to the motor drive circuit MDC2 is 8 m / min (= 10 m / min × 0.8).

[0052] If the set value vm2_sv of the rotational speed of motor MT2 is equal to the measured value vm2_pv, the set value vm3_sv of the rotational speed of motor MT3 output from the speed setting unit 73 to the motor drive circuit MDC3 is 4 m / min (= 8 m / min × 0.5). When the draw ratio falls below 100%, the resin film 83 becomes relaxed.

[0053] In the control unit 700 according to the comparative example, when adjusting the rotation speed of the roll R2, the operator had to manually adjust the draw ratio dr2 input to the speed setting unit 72 while visually observing, for example, the state of the resin film 83 on the roll R2. Similarly, when adjusting the rotation speed of the roll R3, the operator had to manually adjust the draw ratio dr3 input to the speed setting unit 73 while visually observing, for example, the state of the resin film 83 on the roll R3. The same applies when adjusting the rotation speeds of the other rolls. Such adjustment work requires skill, which has led to problems such as variations in adjustment time depending on the operator's level of proficiency.

[0054] <Configuration of the control unit 70 according to the first embodiment> Next, the configuration of the control unit 70 in the resin film conveying machine (i.e., the longitudinal stretching machine 40) according to the first embodiment will be described in more detail with reference to Fig. 4. Fig. 4 is a block diagram showing the configuration of the control unit 70 according to the first embodiment.

[0055] As shown in FIG. 4, the control unit 70 according to the first embodiment includes speed setting units 71, 72a, ... that set the rotation speeds of the rolls R1 to R11 included in the longitudinal stretching machine 40 shown in FIGS. 1 and 2. In the control unit 70 shown in FIG. 4, a speed setting unit 71 that sets the speed of the forefront roll R1 has the same configuration as the speed setting unit 71 in the control unit 700 shown in FIG.

[0056] On the other hand, in the control unit 70 shown in Fig. 4, a speed setting unit 72a that sets the speed of the roll R2 has a different configuration from the speed setting unit 72 in the control unit 700 shown in Fig. 3. Also, in the control unit 70 shown in Fig. 4, speed setting units (not shown) that set the rotation speeds of the rolls R3 to R11 each have a configuration similar to that of the speed setting unit 72a. Therefore, the configuration of the speed setting unit 72a that sets the speed of the roll R2 will be described below.

[0057] 4, the speed setting unit 72a includes a tension calculation unit 721, a deviation calculation unit 722, a correction amount determination unit 723, a draw ratio correction unit 724, and a speed calculation unit 725. Here, the speed calculation unit 725 corresponds to the speed setting unit 72 shown in FIG. Therefore, the speed setting unit 72a shown in FIG. 4 is configured to include a tension calculation unit 721, a deviation calculation unit 722, a correction amount determination unit 723, and a draw ratio correction unit 724 in addition to the speed setting unit 72 shown in FIG.

[0058] 4, tension calculation unit 721 uses the torque measurement value t_pv fed back from motor drive circuit MDC2 to calculate the tension measurement value f_pv of resin film 83. Here, torque measurement value t_pv is an index indicating the state of resin film 83 on roll R2, which is the control target. The measured torque value t_pv may be measured by a torque sensor provided separately from the motor drive circuit MDC2.

[0059] Here, if the diameter of the roll R2 is D, the measured value f_pv of the tension of the resin film 83 can be calculated based on the following formula (1). f_pv=2×t_pv / D Equation (1) Furthermore, the measured value f_pv of the tension of the resin film 83 may be calculated after correcting the formula (1) in consideration of mechanical loss.

[0060] The deviation calculation unit 722 calculates the difference between the measured tension value f_pv acquired from the tension calculation unit 721 and the tension setting value f_sv, which is the target value, i.e., the tension control deviation f_err (=f_pv-f_sv). In other words, the deviation calculation unit 722 is a subtraction circuit. Here, the tension setting value f_sv is input by the operator, but is not usually changed during operation.

[0061] The correction amount determination unit 723 determines the correction amount Δdr for the draw ratio dr2 based on the tension control deviation f_err acquired from the deviation calculation unit 722. The correction amount determination unit 723 may determine the correction amount Δdr using, for example, PID control.

[0062] First, the correction amount determination unit 723 determines whether the tension control deviation f_err acquired from the deviation calculation unit 722 is within the allowable range, i.e., whether the allowable lower limit value≦f_err≦the allowable upper limit value. Here, the allowable range, i.e., the allowable lower limit value and the allowable upper limit value, are set appropriately.

[0063] If the tension control deviation f_err is within the allowable range, there is no need to correct the draw ratio, so the correction amount Δdr is set to 0. When the control deviation f_err of the tension of the resin film 83 is greater than the allowable upper limit, the measured value f_pv of the tension of the resin film 83 is too large compared to the set value f_sv. Therefore, the correction amount determination unit 723 sets the correction amount Δdr<0 so that the draw ratio becomes smaller.

[0064] On the other hand, if the control deviation f_err of the tension of the resin film 83 is less than the allowable lower limit, the measured value f_pv of the tension of the resin film 83 is too small compared to the set value f_sv. Therefore, the correction amount determination unit 723 sets the correction amount Δdr to be greater than 0 so that the draw ratio increases. The larger the absolute value of the tension control deviation f_err, the larger the absolute value of the correction amount Δdr.

[0065] The draw ratio correction unit 724 corrects the draw ratio dr2 input by the operator based on the correction amount Δdr acquired from the correction amount determination unit 723, and outputs the corrected draw ratio dr_corr. Specifically, the draw ratio correction unit 724 outputs the sum of the draw ratio dr2 and the correction amount Δdr as the corrected draw ratio dr_corr (=dr2+Δdr). In other words, the draw ratio correction unit 724 is an addition circuit.

[0066] The speed calculation unit 725 multiplies the measured value vm1_pv of the rotational speed of the motor MT1, acquired from the motor drive circuit MDC1, by the corrected draw ratio dr_corr, acquired from the draw ratio correction unit 724, to calculate the set value vm2_sv (=vm1_pv×dr_corr) of the rotational speed of the motor MT2. As described above, the speed calculation unit 725 is a multiplication circuit similar to the speed setting unit 72 shown in FIG. 3. Here, the draw ratio dr2 is input by the operator. In other words, the set value vm2_sv of the rotational speed of the motor MT2 is determined based on the measured value vm1_pv of the rotational speed of the motor MT1.

[0067] The speed calculation unit 725 then outputs the calculated set value vm2_sv of the rotation speed of the motor MT2 to the motor drive circuit MDC2. On the other hand, the measured value vm2_pv of the rotation speed of the motor MT2 detected by the motor drive circuit MDC2 is output from the motor drive circuit MDC2 to a speed setting section (not shown) of the rear roll R3.

[0068] Each functional block constituting the control unit 70 can be configured in hardware by a CPU (Central Processing Unit), memory, and other circuits, and can be realized in software by a program loaded into memory, etc. Therefore, each functional block can be realized in various forms by computer hardware, software, or a combination thereof.

[0069] As described above, in the resin film conveying machine according to the first embodiment, the rotation speed of the motor MT2 is feedback-controlled so that the tension control deviation f_err, which indicates the state of the resin film 83 on the roll R2, approaches 0. Specifically, the draw ratio dr2 input by the operator is automatically feedback-corrected so that the tension control deviation f_err approaches 0.

[0070] That is, in the resin film conveying device according to the first embodiment, the rotation speed of the motor MT2 can be automatically adjusted. Therefore, when adjusting the rotation speed of the roll R2, for example, there is no need to visually observe the state of the resin film 83 on the roll R2, and there is no need for an operator to manually adjust the rotation speed of the roll R2, i.e., the draw ratio dr2. The same applies to the other rolls R3 to R11 included in the resin film transport machine (namely, the longitudinal stretching machine 40) according to the first embodiment.

[0071] <Control method for resin film conveyor> Next, a method for controlling a resin film conveying machine (i.e., a longitudinal stretching machine 40) according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing the method for controlling a resin film conveying machine according to the first embodiment. In Fig. 5 as well, the control by a speed setting unit 72a that sets the speed of the roll R2 shown in Fig. 4 will be described as an example.

[0072] First, as shown in Fig. 5, a measured value (PV value) f_pv of tension of the resin film 83 is calculated from a detected measured value (PV value) t_pv of torque (step S1). Specifically, as shown in Fig. 4, tension calculation unit 721 calculates a measured value f_pv of tension of the resin film 83 on roll R2 using the measured value t_pv of torque fed back from motor drive circuit MDC2. Here, the measured value t_pv of torque is an index indicating the state of the resin film 83 on roll R2, which is the object of control.

[0073] Next, as shown in Fig. 5, the control deviation f_err between the tension measurement value (PV value) f_pv and the set value (SV value) f_sv is calculated (step S2). Specifically, as shown in Fig. 4, the deviation calculation unit 722 calculates the tension control deviation f_err (=f_pv-f_sv), which is the difference between the tension measurement value f_pv acquired from the tension calculation unit 721 and the tension set value f_sv, which is the target value.

[0074] Next, as shown in Fig. 5, it is determined whether the tension control deviation f_err is within the allowable range (step S3). Specifically, as shown in Fig. 4, the correction amount determination unit 723 determines whether the tension control deviation f_err acquired from the deviation calculation unit 722 is within the allowable range, i.e., whether the allowable lower limit value ≦ f_err ≦ the allowable upper limit value.

[0075] If the tension control deviation f_err is not within the allowable range (NO in step S3), the draw ratio is corrected so that the control deviation f_err becomes smaller (step S4). Specifically, as shown in Fig. 4, a correction amount determination unit 723 determines a correction amount Δdr for the draw ratio so that the control deviation f_err becomes smaller. Then, a draw ratio correction unit 724 corrects the draw ratio dr2 input by the operator based on the correction amount Δdr. After that, steps S1 to S3 are executed again.

[0076] On the other hand, if the tension control deviation f_err is within the allowable range (YES in step S3), the roll speed adjustment is terminated. That is, steps S1 to S4 are repeated until the tension control deviation f_err falls within the allowable range. As a result of the above, the speed of the roll R2 can be adjusted (that is, the draw ratio can be corrected).

[0077] The speed adjustment shown in Fig. 5 is performed for each of the rolls R2 to R11 shown in Fig. 1 and Fig. 2. For example, the speed adjustment shown in Fig. 5 is performed in the order of the rolls R2 to R11 (i.e., in order from the front roll). The speed adjustment performed in the order of the rolls R2 to R11 may also be repeated multiple times.

[0078] As described above, in the control method for a resin film conveying machine according to the first embodiment, the rotation speed of the motor MT2 is feedback controlled so that the tension control deviation f_err, which indicates the state of the resin film 83 on the roll R2, approaches 0. Specifically, the draw ratio dr2 input by the operator is automatically feedback corrected so that the tension control deviation f_err approaches 0.

[0079] That is, the control method for a resin film conveying machine according to the first embodiment can automatically adjust the rotation speed of motor MT2. Therefore, when adjusting the rotation speed of roll R2, for example, there is no need to visually observe the state of resin film 83 on roll R2, and there is no need for an operator to manually adjust the rotation speed of roll R2, i.e., draw ratio dr2. The same applies to the other rolls R3 to R11 included in the resin film transport machine (namely, the longitudinal stretching machine 40) according to the first embodiment.

[0080] In the above examples, the program includes instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The program may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disc (DVD), Blu-ray disc or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0081] The invention made by the inventor has been specifically described above based on the embodiments, but it goes without saying that the present invention is not limited to the embodiments already described, and various modifications are possible within the scope of the gist of the invention. [Explanation of symbols]

[0082] 10 Extruder 11 cylinders 12 screws 13 Hopper 20 T-die 30 Cooler 40 Longitudinal stretching machine 50 Lateral stretching machine 60 Winder 70 Control Unit 71, 72a Speed ​​setting section 81 Resin pellets 82, 82a Molten resin 83 Resin film 721 Tension calculation unit 722 Deviation Calculation Unit 723 Correction amount determination unit 724 Draw ratio correction section 725 Speed ​​calculation section CR1~CR4 Cooling rolls MDC1, MDC2, MDC3 motor drive circuits MT1, MT2, MT3 motors R1~R11 roll RL1, RL2 rails

Claims

1. first and second rolls for transporting the extruded resin film; a first drive source that drives the first roll; a second drive source that drives the second roll; a control unit that controls the rotation speeds of the first and second drive sources, the second roll is disposed adjacent to the rear of the first roll, the control unit feedback-controls the rotation speed of the second drive source based on the rotation speed of the first drive source and a draw ratio, The control unit calculating a tension of the resin film from the torque of the second driving source; The difference between the calculated tension and the target tension is calculated as a control deviation. If the control deviation is not within a predetermined allowable range, the draw ratio is corrected so that the control deviation becomes smaller. Resin film conveyor.

2. each of the first and second drive sources is a variable speed motor; The resin film conveying machine according to claim 1.

3. first and second rolls for transporting the extruded resin film; a first drive source that drives the first roll; a second drive source that drives the second roll, the second roll is disposed adjacent to the rear of the first roll, A control method for a resin film conveying machine, wherein a computer feedback-controls a rotation speed of the second drive source based on a rotation speed of the first drive source and a draw ratio, The computer calculating a tension of the resin film from the torque of the second driving source; The difference between the calculated tension and the target tension is calculated as a control deviation. If the control deviation is not within a predetermined allowable range, the draw ratio is corrected so that the control deviation becomes smaller. A method for controlling a resin film conveying machine.

4. each of the first and second drive sources is a variable speed motor; A method for controlling a resin film transporting machine according to claim 3.

5. an extruder that melts and extrudes the input resin raw material; a die connected to the extruder for forming the molten resin into a film; a cooling roll that cools the film-like molten resin extruded from the die and carries out a resin film in which the molten resin has solidified; first and second rolls that transport the resin film carried out from the cooling roll; a first drive source that drives the first roll; a second drive source that drives the second roll; a control unit that controls the rotation speeds of the first and second drive sources, the second roll is disposed adjacent to the rear of the first roll, The control unit feedback-controls the rotation speed of the second drive source based on the rotation speed of the first drive source and a draw ratio, The control unit calculating a tension of the resin film from the torque of the second driving source; The difference between the calculated tension and the target tension is calculated as a control deviation. If the control deviation is not within a predetermined allowable range, the draw ratio is corrected so that the control deviation becomes smaller. Resin film manufacturing equipment.

6. each of the first and second drive sources is a variable speed motor; The resin film manufacturing apparatus according to claim 5 .

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