JP7844874B2 - Thickness adjustment device and thickness adjustment method - Google Patents

Description

This invention relates to a thickness adjustment device and a thickness adjustment method.

One method for manufacturing resin films made from thermoplastic resins is the use of a die. The die has slits, and by extruding molten resin through these slits, it is possible to form a thin resin film. The thickness of the resin film can be adjusted by changing the spacing of the slits through which the molten resin passes.

For example, Patent Document 1 describes arranging multiple die bolts equipped with heaters in the width direction of the die, thereby adjusting the lip spacing of the die using the die bolts. Patent Document 2 describes arranging multiple heat bolts along the width direction of the movable lip of the lip portion formed on the die, and adjusting the slit spacing by changing the pressing force against the movable lip by moving or expanding/contracting the heat bolts axially. Furthermore, Patent Document 3 describes a screw-in device that can tighten screws to set the height of the die gap of a slot die, and is movably arranged along a cross member. In Patent Document 3, by moving the screw-in device using a drive device, it is possible to rotate multiple screws arranged on the slot die using the screw-in device.

Special Publication No. 1-22140 Japanese Patent Publication No. 2007-290141 U.S. Patent Application Publication No. 2013/334730

However, since numerous bolts are positioned on the die used to mold the resin film, manually adjusting the pressure applied by the bolts is cumbersome. Furthermore, while the bolts can be rotated by fitting a wrench onto their heads, as described in Patent Document 3, when the screw-in device is moved by a drive mechanism and stopped at a desired bolt position, it may not be possible to fit a wrench onto the bolt head.

In other words, because the gap between the wrench and the bolt when the wrench is fitted to the bolt head is very small, if the screw-in device stops in a misaligned position relative to the bolt, the wrench will no longer fit to the bolt, making it impossible to rotate the bolt. For these reasons, it is difficult to adjust the thickness of the film ejected from the die by adjusting the bolts positioned in the die.

This disclosure has been made in view of the above, and aims to provide a thickness adjustment device and a thickness adjustment method that can easily adjust the thickness of a film.

To achieve the above objective, a thickness adjustment device according to one aspect of this disclosure comprises: a die for discharging a resin film from a slit formed between a pair of separated lip portions; a plurality of adjustment bolts arranged in a line along the extending direction of the lip portions, which adjust the spacing between the slits by applying a pressing force to the lip portions; a rotating device having a fitting portion that engages with the adjustment bolts and which rotates the adjustment bolts by engaging the fitting portion with the adjustment bolts; a traveling device for moving the rotating device along the direction in which the plurality of adjustment bolts are aligned; a bolt detection unit that moves together with the rotating device by the traveling device and detects the presence or absence of the adjustment bolts in the direction of movement; and a bolt position calculation unit that calculates the position of each adjustment bolt in the direction in which the plurality of adjustment bolts are aligned based on the detection result of the adjustment bolts by the bolt detection unit.

This allows the rotating device that rotates the adjustment bolts for adjusting the slit spacing to be moved by the traveling device in the direction in which multiple adjustment bolts are aligned. By moving the device based on the position of each adjustment bolt calculated by the bolt position calculation unit, the rotating device can be moved to the desired adjustment bolt position with high precision. Therefore, when adjusting the slit spacing by adjusting the pressing force of the adjustment bolts against the die lip, the fitting portion of the rotating device can be fitted to the desired adjustment bolt, and the rotating device can rotate the desired adjustment bolt. As a result, the film thickness can be easily adjusted.

In one embodiment of the thickness adjustment device of this disclosure, the movement speed of the bolt detection unit by the traveling device and the bolt position acquisition time (the time required from the detection of the presence or absence of the adjustment bolt by the bolt detection unit until the position of the adjustment bolt is calculated by the bolt position calculation unit) are such that the difference between the position of the adjustment bolt calculated by the bolt position calculation unit (which receives the detection result from the bolt detection unit detecting the presence or absence of the adjustment bolt while moving by the traveling device via communication) and the actual position of the adjustment bolt is within the range of the allowable gap between the fitting unit and the adjustment bolt that is permitted when the fitting unit is fitted onto the adjustment bolt.

This allows the rotating device to move in the direction where multiple adjustment bolts are aligned, based on the position of the adjustment bolts calculated by the bolt position calculation unit. When engaging the fitting portion of the rotating device with the adjustment bolts, the fitting portion can be properly engaged. Therefore, when adjusting the slit spacing by adjusting the pressing force of the adjustment bolts against the die lip, the target adjustment bolt can be rotated by the rotating device. As a result, the film thickness can be easily adjusted.

To achieve the above objective, a thickness adjustment method according to one aspect of this disclosure includes a step of measuring the thickness of a resin film discharged from a slit in a die having a slit formed between a pair of separated lip portions, and a step of adjusting the spacing between the slits by adjusting the pressing force applied to the lip portions by adjustment bolts arranged in a row along the extending direction of the lip portions, based on the measured thickness of the resin film. The method involves pre-calculating the position of each adjustment bolt in the direction in which the adjustment bolts are arranged, based on a detection result from a bolt detection unit that moves along the direction in which the adjustment bolts are arranged together with a rotating device that rotates the adjustment bolts. When adjusting the spacing between the slits, the slit spacing is adjusted by fitting a fitting portion of the rotating device onto the adjustment bolt and rotating the adjustment bolt based on the calculated position of each adjustment bolt.

This allows for easy adjustment of the slit spacing during film manufacturing. The rotating device is moved based on pre-calculated positions for each adjustment bolt, engaging the device's fitting mechanism with the adjustment bolt, and then the desired adjustment bolt is rotated to adjust the slit spacing. As a result, the film thickness can be easily adjusted.

The thickness adjustment device and thickness adjustment method of this disclosure have the effect of allowing for easy adjustment of the film thickness.

Figure 1 is a schematic diagram of an extrusion molding apparatus according to an embodiment. Figure 2 is a cross-sectional view of the die shown in Figure 1. Figure 3 is a perspective view of the die shown in Figure 1. Figure 4 is a block diagram showing the device configuration of a thickness adjustment device according to an embodiment. Figure 5 is an explanatory diagram showing the state in which the laser displacement sensor detects the position of the adjustment bolt, and is a schematic diagram of the state in which the laser displacement sensor does not detect the adjustment bolt. Figure 6 is an explanatory diagram showing the state in which the position of the adjustment bolt is detected by the laser displacement sensor, and is a schematic diagram of the state in which the laser displacement sensor is detecting the adjustment bolt. Figure 7 is an explanatory diagram of how to obtain the center position of the adjustment bolt. Figure 8 is an explanatory diagram showing a state in which the laser beam emitted from the laser displacement sensor is positioned at an angle to the axial direction of the adjustment bolt. Figure 9 is an explanatory diagram showing the detection position relative to the adjustment bolt when detecting the adjustment bolt with the laser displacement sensor shown in Figure 8. Figure 10 is an explanatory diagram showing a state in which the laser beam emitted from the laser displacement sensor is positioned parallel to the axial direction of the adjustment bolt. Figure 11 is an explanatory diagram showing the detection position relative to the adjustment bolt when detecting the adjustment bolt with the laser displacement sensor shown in Figure 10. Figure 12 is an explanatory diagram illustrating the information discrepancy caused by communication lag. Figure 13 is an explanatory diagram of the gap between the fitting hole formed in the socket of the rotating device and the bolt head of the adjustment bolt.

The present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the embodiments described below. Furthermore, the components in the embodiments below include those easily conceivable by those skilled in the art, those substantially identical, and those within the so-called equivalent range. Moreover, the components disclosed in the embodiments below can be combined as appropriate.

[Embodiment]
Figure 1 is a schematic diagram of an extrusion molding apparatus 1 according to this embodiment. The extrusion molding apparatus 1 according to this embodiment is an apparatus for manufacturing a thin-film resin film F using a synthetic resin. The extrusion molding apparatus 1 is an apparatus for manufacturing a single-layer film. A single-layer film is a film formed from one type of raw material. Note that the extrusion molding apparatus 1 may also be an apparatus for creating multi-layer films.

As shown in Figure 1, the extrusion molding apparatus 1 comprises an extruder 11, an extrusion die 20, a casting roll 13 (which serves as a cooling roll), a conveying roll 14, a thickness gauge 15, a winding machine 16, and a control device 80.

The extruder 11 is a device that pushes molten resin toward the die 20. Resin is supplied as material to the hopper of the extruder 11. The resin supplied to the hopper is preheated and kneaded, and formed into pellets. The pelletized resin is guided from the hopper to the cylinder of the extruder 11. The cylinder is equipped with a screw. The resin is melted by the screw and extruded toward the die 20.

The die 20 is a device that forms molten resin into a film. Molten resin is supplied from the extruder 11 to the upper side of the die 20. The molten resin supplied from the extruder 11 to the die 20 moves downward inside the die 20 and is discharged from the lower end of the die 20.

The cast roll 13 comes into contact with the film-like resin extruded from the die 20. The cast roll 13 cools and solidifies the film-like resin extruded from the die 20. As a result, the extrusion molding apparatus 1 produces a resin film F, which is a film made of resin material. In this description, the resin extruded from the die 20 and before solidification by the cast roll 13 is also formed in a thin film form, and for convenience, it will be described as a resin film F.

Multiple conveyor rolls 14 are arranged in the extrusion molding apparatus 1. The conveyor rolls 14 transport the resin film F, solidified by the cast roll 13, toward the side where the winding machine 16 is located.

The thickness gauge 15 is a device for measuring the thickness of the resin film F. The thickness gauge 15 measures the thickness of the resin film F at multiple locations in the width direction of the resin film F. The thickness gauge 15 can, for example, use a laser beam to non-contactually measure the thickness of the resin film F at multiple positions in the width direction of the resin film F. The thickness gauge 15 outputs the measured thickness of the resin film F to the control device 80.

The winding machine 16 is positioned downstream of the thickness gauge 15 in the transport direction of the resin film F. The winding machine 16 winds up the resin film F after it has passed the thickness gauge 15.

The control device 80 is a computer and includes, for example, a CPU (Central Processing Unit), ROM (Read-Only Memory), RAM (Random Access Memory), an input interface, and an output interface. In the control device 80, the CPU, ROM, RAM, input interface, and output interface are connected to an internal bus. The functions of the control device 80 are realized through the cooperation of the CPU, ROM, RAM, input interface, and output interface. In this embodiment, a PLC (Programmable Logic Controller) is used for the control device 80.

Figure 2 is a cross-sectional view of the die 20 shown in Figure 1. In the following description of the die 20, the vertical direction in the die 20's normal usage will be referred to as the vertical direction Z of the die 20. Furthermore, the width direction of the resin film F (see Figure 1) extruded from the die 20 will be referred to as the width direction Y of the die 20, and the direction perpendicular to the vertical direction Z and the width direction Y will be referred to as the thickness direction X of the die 20.

The die 20 has an input section 21, an introduction channel 22, a lip section 23, and a slit 25. The input section 21 is the part into which the molten resin supplied from the extruder 11 is introduced into the die 20, and is formed at the upper end of the die 20 in a perforated shape. A supply member 12, which constitutes the supply path for the molten resin from the extruder 11 to the die 20, is connected to the input section 21, and the molten resin is supplied to the die 20 through the supply member 12.

The introduction channel 22 is a perforated channel formed upstream of the slit 25, which is the part of the die 20 that dispenses molten resin. The introduction channel 22 is formed between the input section 21 and the slit 25 and is connected to both.

The introduction channel 22 has a vertical channel 22a and a horizontal channel 22b. The vertical channel 22a extends in the vertical direction Z, and its upper end forms the input section 21. The shape of the vertical channel 22a, when viewed in the vertical direction Z, is, for example, a circular hole. The inner diameter of the vertical channel 22a is significantly smaller than its size in the width direction Y of the die 20, and it is formed near the center of the die 20 in both the width direction Y and the thickness direction X.

The transverse channel 22b is formed near the center of the die 20 in the thickness direction X and extends in the width direction Y of the die 20. The lower end of the longitudinal channel 22a in the vertical direction Z is connected to the transverse channel 22b. Therefore, when the resin flowing through the longitudinal channel 22a reaches the transverse channel 22b, it spreads out in the width direction Y along the transverse channel 22b. In the portion of the transverse channel 22b closer to the lower end in the vertical direction Z, its size in the thickness direction X decreases as it moves downwards.

The lip portion 23 is positioned near the lower end in the vertical direction Z. The lip portion 23 has a fixed lip 23a and a movable lip 23b. Both the fixed lip 23a and the movable lip 23b extend in the width direction Y; that is, the lip portion 23 is formed extending in the width direction Y of the die 20. The fixed lip 23a and the movable lip 23b, formed in this manner, are positioned with a gap between them in the thickness direction X of the die 20. The gap between the fixed lip 23a and the movable lip 23b is formed as a slit 25. Because the slit 25 is formed as the gap between the fixed lip 23a and the movable lip 23b, the slit 25 extends in the width direction Y, which is the direction in which the lip portion 23 extends.

The lateral channel 22b of the introduction channel 22 has a length in the width direction Y that is approximately equal to the length of the slit 25 in the width direction Y, and the lower end of the lateral channel 22b in the vertical direction Z is connected to the slit 25. The slit 25 is an outlet that discharges the molten resin flowing through the introduction channel 22 to the outside of the die 20. The slit 25 can discharge the molten resin in the form of a thin resin film F (see Figure 1). That is, the die 20 is capable of discharging the resin film F from the slit 25 formed between a pair of separated lip portions 23.

The resin film F is extruded from the slit 25 such that its width is approximately the same as the length of the slit 25 in the width direction Y, and its thickness is approximately the same as the distance between the fixed lip 23a and the movable lip 23b in the thickness direction X. Therefore, the width direction Y of the die 20 and the width direction of the resin film F are substantially the same.

The adjustment bolt 30 is a component for adjusting the thickness of the resin film F extruded from the slit 25 formed by the lip portion 23. The adjustment bolt 30 is rotatably supported by a bolt support portion 31 attached to the die 20. Both the adjustment bolt 30 and the bolt support portion 31 are positioned only on the side of the die 20 where the movable lip 23b is located, in the thickness direction X. One end of the adjustment bolt 30, supported by the bolt support portion 31, is connected to the movable lip 23b. The adjustment bolt 30 can adjust the spacing of the slit 25 by applying a pressing force to the lip portion 23.

In other words, when the adjustment bolt 30 rotates relative to the bolt support portion 31, the length of the portion of the adjustment bolt 30 located between the bolt support portion 31 and the movable lip 23b changes. This allows the adjustment bolt 30 to change the pressing force applied to the lip portion 23. When the pressing force applied to the lip portion 23 by the adjustment bolt 30 changes, that is, when the pressing force applied to the movable lip 23b by the adjustment bolt 30 changes, the distance between the movable lip 23b and the fixed lip 23a changes. By changing the pressing force applied to the lip portion 23 in this way, the adjustment bolt 30 can adjust the spacing of the slit 25 formed between the movable lip 23b and the fixed lip 23a, thereby adjusting the thickness of the resin film F discharged from the slit 25.

Figure 3 is a perspective view of the die 20 shown in Figure 1. Multiple adjustment bolts 30 are arranged in a row along the extending direction of the lip portion 23. That is, multiple adjustment bolts 30 are arranged in a row along the width direction Y. The die 20 is equipped with an automatic adjustment device 40 that uses an actuator to adjust the spacing of the slits 25 using the adjustment bolts 30. The automatic adjustment device 40 includes an adjustment device support portion 41, a rotating device 50, and a traveling device 60.

The automatic adjustment device 40 is positioned on the side of the die 20 where the adjustment bolt 30 is located, in the thickness direction X. The length of the automatic adjustment device 40 in the width direction Y is approximately the same as the width of the die 20 in the width direction Y. The automatic adjustment device 40 has adjustment device support parts 41 on both sides in the width direction Y, and these support parts 41 are attached to the end faces of the die 20 in the width direction Y. Thus, the automatic adjustment device 40 is attached to the die 20 by the adjustment device support parts 41.

The rotating device 50 comprises a rotating device actuator 51 and a socket 53. The rotating device actuator 51 is an actuator for rotating the adjustment bolt 30. The socket 53 is a fitting portion that can be fitted with the adjustment bolt 30. For example, the bolt head 30a (see Figure 7), which is the portion of the adjustment bolt 30 that fits into the socket 53, is formed in a substantially regular hexagonal shape when viewed in the axial direction of the adjustment bolt 30. The socket 53 is formed in a socket-like shape with an inner portion that is substantially hexagonal, allowing it to be fitted onto the adjustment bolt 30. A shaft portion 52, which is an axial member, extends from the rotating device actuator 51, and the socket 53 is positioned at the tip of the shaft portion.

The rotating actuator 51 is formed by integrating an electric motor and a linear motor, allowing the actuator 51 to rotate the shaft 52 and extend or retract the shaft 52 in the direction of its extension. By extending or retracting the shaft 52, the actuator 51 can engage the socket 53, located at the tip of the shaft 52, with the adjustment bolt 30, or disengage the socket 53 from the adjustment bolt 30 while it is engaged. Furthermore, the actuator 51 can rotate the adjustment bolt 30 by rotating the socket 53 while it is engaged with the adjustment bolt 30.

The traveling device 60 is a device that moves the rotating device 50 along the direction in which the multiple adjustment bolts 30 are aligned, and includes a traveling device actuator 61, a rotating device support 62, a traveling rail 63, and a belt 64. The traveling device actuator 61 is the power source for the traveling device 60, and for example, an electric motor that operates using electricity is used. The traveling device actuator 61 is equipped with an encoder, and the rotation angle and rotation speed of the traveling device actuator 61 can be detected by the encoder.

The rotating device support section 62 supports the rotating device 50. Specifically, the rotating device actuator 51 is attached to the rotating device support section 62. The rotating device actuator 51 is attached to the rotating device support section 62 in such a orientation that its shaft portion 52 is parallel to the axial direction of the adjustment bolt 30 located on the die 20, and the socket 53 faces the adjustment bolt 30.

The running rail 63 is a rail for running the rotating device support 62, and is arranged extending in the width direction Y of the die 20. That is, the running rail 63 extends along the direction in which the multiple adjustment bolts 30 arranged on the die 20 are aligned, and the rotating device support 62 can move along the running rail 63, thereby moving along the direction in which the multiple adjustment bolts 30 are aligned.

The belt 64 transmits power generated by the travel device actuator 61 to the rotating device support 62, thereby enabling the rotating device support 62 to move along the travel rail 63. Therefore, the travel device 60, which supports the rotating device 50 with the rotating device support 62, is able to move the rotating device 50 along the direction in which the multiple adjustment bolts 30 are aligned.

The automatic adjustment device 40, configured in this manner, includes a control unit 45 (see Figure 4) that controls the rotating device 50 and the traveling device 60. The control unit 45 is a computer and includes, for example, a CPU, ROM, RAM, an input interface, and an output interface. In the control unit 45, the CPU, ROM, RAM, input interface, and output interface are connected to an internal bus. The functions of the control unit 45 are realized through the coordinated operation of the CPU, ROM, RAM, input interface, and output interface.

The control unit 45 can extend and retract the shaft portion 52 or rotate the socket 53 by controlling the rotating device actuator 51 of the rotating device 50. Furthermore, the control unit 45 can move the rotating device 50 along the travel rail 63 by controlling the travel device actuator 61 of the travel device 60. In this process, the control unit 45 can obtain the position of the rotating device 50 in the direction of movement, i.e., the position of the rotating device 50 in the width direction Y, by acquiring the detection result of the encoder of the travel device actuator 61. For example, the control unit 45 uses one end of the movement range of the rotating device 50 moved by the travel device 60 as a reference position, and obtains the position of the rotating device 50 in the width direction Y from the reference position based on the detection result of the encoder of the travel device actuator 61.

Furthermore, the automatic adjustment device 40 is equipped with a laser displacement sensor 70, which is a bolt detection unit that detects the presence or absence of adjustment bolts 30 placed on the die 20. The laser displacement sensor 70 comprises an irradiation unit (not shown) that emits laser light and a light receiving unit (not shown) that receives the reflected light emitted from the irradiation unit and reflected by the object. By receiving the reflected light reflected by the object, the presence or absence of the object can be detected.

In this embodiment, the laser displacement sensor 70 is positioned opposite the adjustment bolt 30 located on the die 20. It is capable of irradiating the adjustment bolt 30 with laser light and detecting the reflected light from the laser beam. In other words, the laser displacement sensor 70 is positioned to detect the adjustment bolt 30 located on the die 20, and is capable of detecting the presence or absence of the adjustment bolt 30.

The laser displacement sensor 70 is attached to the rotating device support portion 62 of the traveling device 60 and is supported by the rotating device support portion 62 together with the rotating device 50. This allows the laser displacement sensor 70 to move together with the rotating device 50 via the traveling device 60, enabling detection of the presence or absence of the adjustment bolt 30 in the direction of movement, i.e., the presence or absence of the adjustment bolt 30 at each position in the width direction Y.

Figure 4 is a block diagram showing the configuration of the thickness adjustment device 100 according to this embodiment. In this embodiment, the automatic adjustment device 40 attached to the die 20 of the extrusion molding apparatus 1, the laser displacement sensor 70 positioned in the automatic adjustment device 40, and the control device 80 constitute the thickness adjustment device 100 for adjusting the thickness of the resin film F. Specifically, the control device 80 is capable of communicating with the control unit 45 of the automatic adjustment device 40 and the laser displacement sensor 70. Communication between the laser displacement sensor 70 and the control device 80, and between the control unit 45 of the automatic adjustment device 40 and the control device 80, may be conducted via wired or wireless communication. The laser displacement sensor 70 and the control device 80, and the control unit 45 of the automatic adjustment device 40 and the control device 80, are connected, for example, via Ethernet (registered trademark), enabling communication between them.

The laser displacement sensor 70, while moving in the width direction Y of the die 20 by the travel device 60 of the automatic adjustment device 40, transmits the detection result of the presence or absence of the adjustment bolt 30 to the control device 80.

The control device 80 transmits to the control unit 45 of the automatic adjustment device 40 that the presence or absence of the adjustment bolt 30 has been detected by the laser displacement sensor 70. The control unit 45 then transmits to the control device 80 the position of the rotating device 50 in the width direction Y at the time the control device 80 transmitted the detection of the presence or absence of the adjustment bolt 30. Based on this, the control device 80 calculates the position of the adjustment bolt 30 in the width direction Y, as detected by the laser displacement sensor 70, using the position of the rotating device 50 transmitted from the control unit 45 of the automatic adjustment device 40.

The control device 80, as described above, functions as a bolt position calculation unit, calculating the position of each adjustment bolt 30 in the direction in which multiple adjustment bolts 30 are aligned, based on the detection results of the adjustment bolts 30 by the laser displacement sensor 70.

The extrusion molding apparatus 1, configured as described above, acquires the position of each of the multiple adjustment bolts 30 placed on the die 20 before molding the resin film F. The position of the adjustment bolts 30 is acquired by the thickness adjustment device 100. The thickness adjustment device 100 acquires the position of the adjustment bolts 30 by moving the laser displacement sensor 70 in the width direction Y using the travel device 60 of the automatic adjustment device 40, and detecting the presence or absence of the adjustment bolts 30 with the laser displacement sensor 70.

Figure 5 is an explanatory diagram showing the state in which the laser displacement sensor 70 detects the position of the adjustment bolt 30, and is a schematic diagram of the state in which the laser displacement sensor 70 does not detect the adjustment bolt 30. In Figure 5 and Figure 6 (described later), the adjustment bolt 30 arranged on the die 20 and the laser displacement sensor 70 moving along the direction in which the adjustment bolt 30 is aligned are shown in the upper part of the figure, and a graph of the measurement value by the laser displacement sensor 70 is shown in the lower part of the figure. The graph of the measurement value by the laser displacement sensor 70 in each figure shows the displacement of the detected value of the laser displacement sensor 70 when the laser displacement sensor 70 detects the presence or absence of the adjustment bolt 30. In other words, the graph of the measurement value by the laser displacement sensor 70 in each figure corresponds to the position in the left-right direction of the figure in the upper part of the figure in which the adjustment bolt 30 is shown, and it is shown that the measurement value by the laser displacement sensor 70 is low when the adjustment bolt 30 is not present, and high when the adjustment bolt 30 is present.

When detecting the position of the adjustment bolts 30 using the laser displacement sensor 70, the automatic adjustment device 40's travel device 60 moves the rotating device 50 in the width direction Y of the die 20. As a result, the laser displacement sensor 70 moves together with the rotating device 50 in the width direction Y of the die 20, that is, in the direction where the multiple adjustment bolts 30 are aligned. As the laser displacement sensor 70 moves in the width direction Y, it irradiates laser light L toward the side where the die 20 is located, thereby detecting the presence or absence of the adjustment bolts 30.

When the laser displacement sensor 70, which emits laser light L, is positioned in the width direction of the die 20 where there are no adjustment bolts 30, the laser light L emitted from the laser displacement sensor 70 does not hit the adjustment bolts 30 and is not reflected by them. Therefore, the detection state S of the laser displacement sensor 70, which detects an object by detecting the laser light L reflected from the object, will be low, as shown in the lower graph of Figure 5. This indicates that there are no adjustment bolts 30 at the current position of the laser displacement sensor 70 in the width direction Y.

Figure 6 is an explanatory diagram showing the state in which the laser displacement sensor 70 detects the position of the adjustment bolt 30. It is a schematic diagram of the state in which the laser displacement sensor 70 detects the adjustment bolt 30. When the laser displacement sensor 70, which emits laser light L while moving in the width direction Y, moves to the position where the adjustment bolt 30 is located in the width direction of the die 20, the laser light L emitted from the laser displacement sensor 70 strikes the adjustment bolt 30 and is reflected by the adjustment bolt 30. The laser displacement sensor 70 receives the reflected light of the laser light L reflected by the adjustment bolt 30, and the detection state S of the laser displacement sensor 70 becomes high, as shown in the lower graph of Figure 6. This indicates that the adjustment bolt 30 is located at the current position of the laser displacement sensor 70 in the width direction Y.

The laser displacement sensor 70 detects the presence or absence of the adjustment bolt 30 at its current position in the width direction Y by irradiating the die 20 with laser light L. Furthermore, the laser displacement sensor 70 detects the presence or absence of the adjustment bolt 30 at each position in the width direction Y by irradiating laser light L while moving along the direction in which the multiple adjustment bolts 30 are aligned, using the travel device 60 of the automatic adjustment device 40. The detection results of the laser displacement sensor 70 for detecting the presence or absence of the adjustment bolt 30 are transmitted to the control device 80.

The control device 80 transmits the detection result detected by the laser displacement sensor 70 to the control unit 45 of the automatic adjustment device 40. The control unit 45 acquires the position of the rotating device 50 based on the detection result of the encoder on the traveling device actuator 61 of the traveling device 60 at the time the detection result from the laser displacement sensor 70 is transmitted from the control device 80. Since the laser displacement sensor 70 moves together with the rotating device 50 by the traveling device 60, the control unit 45 acquires the position of the laser displacement sensor 70 at the time the detection result from the laser displacement sensor 70 is transmitted from the control device 80 by acquiring the position of the rotating device 50.

The control unit 45, having acquired the detection result from the laser displacement sensor 70 and the position of the laser displacement sensor 70 in the width direction Y, links both and transmits them to the control device 80. In other words, the control unit 45 associates the detection result from the laser displacement sensor 70 transmitted from the control device 80 with the position of the laser displacement sensor 70 in the width direction Y at the time the detection result was transmitted, and transmits this information to the control device 80.

The control device 80, which receives information from the control unit 45 of the automatic adjustment device 40 relating the position of the laser displacement sensor 70 in the width direction Y and the detection result from the laser displacement sensor 70, stores this information to acquire the detection result from the laser displacement sensor 70 for each position in the width direction Y. As a result, the control device 80 acquires the presence or absence of adjustment bolts 30 for each position in the direction in which the multiple adjustment bolts 30 are aligned.

The control device 80 further acquires the center position of each of the multiple adjustment bolts 30 arranged in the width direction Y. Figure 7 is an explanatory diagram of the method for acquiring the center position C of the adjustment bolts 30. Figure 7 shows the adjustment bolt 30 viewed in the axial direction of the adjustment bolt 30 from the side where the bolt head 30a, the part into which the socket 53 of the rotating device 50 is fitted, is located.

The laser displacement sensor 70 detects the presence or absence of the adjustment bolt 30 while moving in the width direction Y by the traveling device 60. For example, the laser displacement sensor 70 detects the presence or absence of the bolt head 30a, which is the portion of the adjustment bolt 30 facing the laser displacement sensor 70, while moving in the width direction Y. Specifically, when the laser displacement sensor 70 detects the adjustment bolt 30, it detects the position of the adjustment bolt 30 as the portion between the upstream end and the downstream end of the bolt head 30a in the direction of movement of the laser displacement sensor 70.

Of these, the upstream end of the bolt head 30a in the direction of movement of the laser displacement sensor 70 is the detection start position _P1 , where the laser displacement sensor 70 starts detecting the adjustment bolt 30 when it detects the presence or absence of the adjustment bolt 30 while moving in the width direction Y, from a state where the adjustment bolt 30 is not detected. Also, the downstream end of the bolt head 30a in the direction of movement of the laser displacement sensor 70 is the detection end position P2, where the detection of the adjustment bolt 30 ends, when the laser displacement sensor 70 detects the presence or absence of the adjustment bolt 30 while moving in the width direction _Y , from a state where the adjustment bolt 30 is detected, to a state where the detection of the adjustment bolt 30 ends.

The control device 80, having acquired detection results from the laser displacement sensor 70 at each position in the width direction Y from the control unit 45 of the automatic adjustment device 40, calculates the center position C of the adjustment bolt 30 from the detection start position _P1 and the detection end position _P2 . The control device 80 calculates the position between the respective detection start position _P1 and detection end position _P2 for each adjustment bolt 30 as the center position C of each adjustment bolt 30. In this way, the control device 80 calculates the position in the width direction Y of the center position C of each of the multiple adjustment bolts 30 arranged in the width direction Y of the die 20 and stores it in a storage unit such as RAM in the control device 80.

When the control device 80 calculates the center position C of the adjustment bolt 30 and stores it in its memory, the control device 80 adds or subtracts the distance in the width direction Y of the socket 53 of the rotating device 50 from the position of the laser displacement sensor 70 and stores the result. In other words, the center position C of the adjustment bolt 30 in the width direction Y calculated by the control device 80 is the position used when the automatic adjustment device 40 moves the rotating device 50 in the width direction Y using the travel device 60 and fits the socket 53 of the rotating device 50 onto the adjustment bolt 30. That is, when the automatic adjustment device 40 fits the socket 53 of the rotating device 50 onto the adjustment bolt 30, the travel device 60 moves the rotating device 50 so that the position of the socket 53 in the width direction Y is the same as the center position C of the adjustment bolt 30 in the width direction Y.

Thus, the center position C of the adjustment bolt 30 calculated by the control device 80 is used when fitting the socket 53 of the rotating device 50 onto the adjustment bolt 30. Therefore, the control device 80 converts the position of the center position C of the adjustment bolt 30, calculated based on the detection result of the laser displacement sensor 70, to the position corresponding to the socket 53 of the rotating device 50 and stores it in the memory unit.

Here, the laser beam L emitted from the laser displacement sensor 70 may diffuse slightly depending on the distance from the laser displacement sensor 70. On the other hand, when adjusting the spacing of the slits 25 in the die 20, the adjustment bolt 30 irradiated with the laser beam L moves in the axial direction of the adjustment bolt 30, so the distance of the bolt head 30a to the laser displacement sensor 70 changes. When detecting the presence or absence of the adjustment bolt 30 using the laser beam L, the detection start position _P1 and detection end position _P2 can be detected with higher accuracy as the diffusion of the laser beam L decreases and the range irradiated by the laser beam L decreases. For this reason, it is preferable that the laser displacement sensor 70 is positioned such that the laser beam L irradiated onto the bolt head 30a of the adjustment bolt 30 moving in the axial direction diffuses less and the irradiated range decreases for bolt heads 30a located within the axial movement range of the bolt head 30a.

The control device 80 not only detects the presence or absence of the adjustment bolt 30 based on the detection results from the laser displacement sensor 70, but also calculates the center position C of the adjustment bolt 30, as shown above. Therefore, the laser displacement sensor 70 is positioned such that the irradiated laser beam L is approximately parallel to the axial direction of the adjustment bolt 30, and the laser beam L passes through the center position C of the adjustment bolt 30.

Figure 8 is an explanatory diagram showing a state in which the laser beam L emitted from the laser displacement sensor 70 is positioned at an angle to the axial direction of the adjustment bolt 30. Figure 9 is an explanatory diagram showing the detection position relative to the adjustment bolt 30 when the adjustment bolt 30 is detected by the laser displacement sensor 70 shown in Figure 8. Figure 9 shows the adjustment bolt 30 shown in Figure 8 as viewed in the axial direction of the adjustment bolt 30 from the side where the bolt head 30a is located. As shown in Figure 8, when the laser beam L emitted from the laser displacement sensor 70 is at an angle to the axial direction of the adjustment bolt 30, the laser beam L emitted from the laser displacement sensor 70 may strike the adjustment bolt 30 at a position away from the center position C.

In other words, the adjustment bolt 30 moves axially when rotated to adjust the spacing of the slits 25 in the die 20. Therefore, if the laser beam L emitted from the laser displacement sensor 70 is inclined relative to the axial direction of the adjustment bolt 30, the position of the bolt head 30a on the surface facing the laser displacement sensor 70 in the direction perpendicular to the width direction Y changes depending on the distance of the adjustment bolt 30 from the laser displacement sensor 70. As a result, depending on the position where the laser beam L strikes the bolt head 30a of the adjustment bolt 30, the laser beam L used to detect the presence or absence of the adjustment bolt 30 may not pass through the actual center position C of the bolt head 30a. In this case, it becomes difficult to calculate the center position C of the adjustment bolt 30 with high accuracy.

For example, as shown as the laser beam path La in Figure 9, if the laser beam L emitted from the laser displacement sensor 70 moves in the width direction Y and passes through a position offset from the center position C of the adjustment bolt 30, the calculated center Ca, calculated from the detection start position _P1 and detection end position _P2 by the laser beam L, may have a position in the width direction Y that is offset from the actual center position C of the adjustment bolt 30. That is, since the bolt head 30a of the adjustment bolt 30 is formed in the shape of a regular hexagon in this embodiment, the orientation of the regular hexagon of the bolt head 30a facing the laser displacement sensor 70 changes depending on the orientation of the adjustment bolt 30 in the rotation direction. Therefore, the positions of the detection start position _P1 and detection end position _P2 by the laser beam L with respect to the regular hexagon of the bolt head 30a change depending on the orientation of the adjustment bolt 30 in the rotation direction.

In this case, as shown in the laser beam path La in Figure 9, if the laser beam L emitted from the laser displacement sensor 70 passes through a position offset from the center position C of the adjustment bolt 30, the distance in the width direction Y from the actual center position _C of the adjustment bolt 30 at the detection start _{position P1} and the detection end position P2 may be different. Therefore, the position in the width direction Y of the calculated center Ca calculated from the detection start position _P1 and the detection end position P2 may be different from the position in the width direction Y of the actual center position C of the adjustment bolt 30, and it may not be possible to calculate the position in the width direction Y of the center position C of the adjustment bolt 30. In such cases, the laser displacement sensor 70 should be installed so that the laser beam L captures the center of the adjustment bolt 30. Specifically, examples include the embodiments described in Figures 10 and 11.

Figure 10 is an explanatory diagram showing the state in which the laser beam L emitted from the laser displacement sensor 70 is positioned parallel to the axial direction of the adjustment bolt 30. Figure 11 is an explanatory diagram showing the detection position relative to the adjustment bolt 30 when the adjustment bolt 30 is detected by the laser displacement sensor 70 shown in Figure 10. Figure 11 shows the adjustment bolt 30 shown in Figure 10 as viewed in the axial direction of the adjustment bolt 30 from the side where the bolt head 30a is located. As shown in Figure 10, if the laser beam L emitted from the laser displacement sensor 70 is parallel to the axial direction of the adjustment bolt 30, and the laser beam L can pass through the center position C when the adjustment bolt 30 is viewed in the axial direction, then the laser beam L emitted from the laser displacement sensor 70 can pass through the center position C regardless of the axial position or rotation angle of the adjustment bolt 30. This allows the center position C of the adjustment bolt 30 to be calculated with high accuracy.

In other words, if the laser beam L emitted from the laser displacement sensor 70 is parallel to the axial direction of the adjustment bolt 30, the laser beam L emitted from the laser displacement sensor 70 while moving in the width direction Y can pass through the center position C of the adjustment bolt 30 regardless of its position in the axial direction of the adjustment bolt 30.

Furthermore, when the laser beam L emitted from the laser displacement sensor 70 while moving in the width direction Y passes through the center position C of the adjustment bolt 30 as shown by the laser beam path La in Figure 11, the detection start position _P1 and the detection end position _P2 by the laser beam L will be the same distance from the center position C of the adjustment bolt 30 in the width direction Y. That is, regardless of the orientation of the regular hexagon of the bolt head 30a, the detection start position _P1 and the detection end position _P2 will be the same distance from the center position C of the adjustment bolt 30 in the width direction Y.

Therefore, the position of the calculation center Ca in the width direction Y, calculated from the detection start position _P1 and the detection end position _P2 , is calculated at the same position as the position of the adjustment bolt 30's center position C in the width direction Y, regardless of the rotational orientation of the regular hexagon shape of the bolt head 30a. Accordingly, the control device 80 can calculate the position of each adjustment bolt 30's center position C in the width direction Y based on the detection start position _P1 and detection end position _P2 emitted by the laser light L from the laser displacement sensor 70.

Here, the position of the adjustment bolt 30 in the width direction Y, calculated by the control device 80, is determined based on the detection result of the presence or absence of the adjustment bolt 30 by the laser displacement sensor 70, which is moved in the width direction Y by the traveling device 60, and the position of the laser displacement sensor 70 in the width direction Y when the traveling device 60 moves it. Information is transmitted between the laser displacement sensor 70 and the control device 80, and between the control unit 45 of the automatic adjustment device 40 and the control device 80, respectively, by wired or wireless communication, but a slight delay occurs in these communications.

Figure 12 is an explanatory diagram of the information shift due to communication lag D. Figure 12(a) is a graph of the detection results when the laser displacement sensor 70 detects the presence or absence of the adjustment bolt 30 while moving in the width direction Y, similar to the graphs shown in Figures 5 and 6. Figure 12(b) is a graph of the position of the adjustment bolt 30 in the width direction Y, acquired by the control device 80, based on the position of the laser displacement sensor 70 in the width direction Y at the time the control unit 45 of the automatic adjustment device 40 acquired the detection result from the laser displacement sensor 70.

In other words, the detection result of the presence or absence of the adjustment bolt 30 by the laser displacement sensor 70 is transmitted to the control unit 45 of the automatic adjustment device 40 via the control device 80. The time acquired by the control unit 45 is delayed due to communication delays, compared to the time the laser displacement sensor 70 detected the presence or absence of the adjustment bolt 30. Meanwhile, the control unit 45 of the automatic adjustment device 40 performs detection while moving the laser displacement sensor 70 in the width direction Y using the travel device 60. Therefore, the position of the laser displacement sensor 70 at the time the detection result of the presence or absence of the adjustment bolt 30 is transmitted to the control unit 45 is the position after moving in the width direction Y compared to the position at the time the laser displacement sensor 70 detected the presence or absence of the adjustment bolt 30.

Therefore, the positions of the multiple adjustment bolts 30 in the width direction Y, acquired by the control device 80 based on the position of the laser displacement sensor 70 in the width direction Y and the detection results from the laser displacement sensor 70, will be different from the positions at which the laser displacement sensor 70 detected the presence or absence of the adjustment bolts 30. That is, the positions of the adjustment bolts 30 acquired by the control device 80 in the width direction Y will be slightly shifted from the positions at which the laser displacement sensor 70 detected the presence or absence of the adjustment bolts 30, due to communication delays between the laser displacement sensor 70 and the control device 80, communication delays between the control unit 45 of the automatic adjustment device 40 and the control device 80, and communication lag D due to processing time in the control device 80 and the control unit 45.

In the thickness adjustment device 100 according to this embodiment, the control device 80 controls the positional deviation of the adjustment bolt 30, which is acquired by the control device 80 due to the communication lag D, so that it remains within the range of deviation between the socket 53 and the adjustment bolt 30 in the direction of movement of the rotating device 50 that is permissible when fitting the socket 53 of the rotating device 50 onto the adjustment bolt 30. In other words, the thickness adjustment device 100 controls the positional deviation of the adjustment bolt 30, acquired by the control device 80, by adjusting the movement speed of the laser displacement sensor 70 and the communication lag D, so that the deviation of the adjustment bolt 30, acquired by the control device 80, remains within the range of deviation in the width direction Y between the socket 53 and the adjustment bolt 30, which allows the socket 53 to be fitted onto the adjustment bolt 30.

In this case, the communication lag D is the bolt position acquisition time, which is the time required from the detection of the presence or absence of the adjustment bolt 30 by the laser displacement sensor 70 until the control device 80 calculates and acquires the position of the adjustment bolt 30 in the width direction Y based on the detection result of the presence or absence of the adjustment bolt 30. The bolt position acquisition time is the sum of the communication time between the laser displacement sensor 70 and the control device 80, the communication time between the control unit 45 of the automatic adjustment device 40 and the control device 80, and the information processing time in the control device 80 and the control unit 45.

In detail, the movement speed and bolt position acquisition time of the laser displacement sensor 70 are set such that the difference between the position of the adjustment bolt 30 calculated by the control device 80 and the actual position of the adjustment bolt 30 is within the allowable gap between the socket 53 and the adjustment bolt 30 when the socket 53 is fitted onto the adjustment bolt 30. That is, because there is a gap between the socket 53 and the bolt head 30a when the socket 53 of the rotating device 50 is fitted onto the bolt head 30a of the adjustment bolt 30, the rotating device 50 and the adjustment bolt 30 can both tolerate a difference equal to the gap between the socket 53 and the bolt head 30a.

Therefore, the thickness adjustment device 100 adjusts the movement speed of the laser displacement sensor 70 and the bolt position acquisition time until the control device 80 acquires the position of the adjustment bolt 30, so that the difference between the position of the adjustment bolt 30 calculated by the control device 80 and the actual position of the adjustment bolt 30 falls within the allowable gap between the socket 53 and the adjustment bolt 30 that is permitted when the socket 53 is fitted onto the adjustment bolt 30. In other words, the movement speed of the laser displacement sensor 70 is slowed down, and the communication time between the laser displacement sensor 70 and the control device 80, and between the control unit 45 and the control device 80, is shortened so that the difference between the position of the adjustment bolt 30 calculated by the control device 80 and the actual position of the adjustment bolt 30 falls within the range of the difference in the width direction Y between the socket 53 and the adjustment bolt 30 that can be fitted by the gap between the socket 53 and the bolt head 30a.

Figure 13 is an explanatory diagram of the gap between the fitting hole 53a formed in the socket 53 of the rotating device 50 and the bolt head 30a of the adjustment bolt 30. In this embodiment, since the socket 53 of the rotating device 50 is formed in a socket shape, the fitting hole 53a that fits into the bolt head 30a, which is formed in a substantially regular hexagon shape, is formed in the socket 53. The fitting hole 53a of the socket 53 is formed in a substantially regular hexagon shape that is slightly larger in size than the bolt head 30a. Therefore, by fitting the fitting hole 53a into the bolt head 30a, the socket 53 can be fitted into the bolt head 30a with relative rotation almost impossible. As a result, the rotating device 50 can rotate the adjustment bolt 30 by rotating the socket 53 with the fitting hole 53a fitted into the bolt head 30a.

The gap between the fitting hole 53a of the socket 53 and the bolt head 30a is, specifically, as shown in Figure 13, large enough to allow the hexagonal shapes of the fitting hole 53a and the bolt head 30a to fit together with a 1° offset from each other in the rotational direction. The fitting hole 53a of the socket 53 is slightly larger than the bolt head 30a, creating a gap between it and the bolt head 30a that allows for this slight rotational offset of the hexagonal shapes.

As a result, even if the position of the socket 53's fitting hole 53a is slightly misaligned with the bolt head 30a in the direction of movement of the socket 53, the fitting hole 53a can still fit onto the bolt head 30a if the orientation of the regular hexagons of the fitting hole 53a and the bolt head 30a is the same in the direction of rotation. Thus, the maximum amount of misalignment between the socket 53 and the adjustment bolt 30 in the direction of movement of the socket 53, when the orientation of the regular hexagons of the fitting hole 53a and the bolt head 30a is the same in the direction of rotation, is the allowable clearance.

The movement speed of the laser displacement sensor 70 and the bolt position acquisition time are set so that the difference between the position of the adjustment bolt 30 calculated by the control device 80 and the actual position of the adjustment bolt 30 falls within the allowable gap between the fitting hole 53a of the socket 53 (which has a gap when fitted) and the bolt head 30a of the adjustment bolt 30. In this embodiment, for example, the movement speed of the laser displacement sensor 70 is set to 20 mm/sec, and the bolt position acquisition time, which is the time from when the laser displacement sensor 70 detects the presence or absence of the adjustment bolt 30 until the control device 80 calculates the position of the adjustment bolt 30, is set to 1 ms.

In this embodiment, the set of positional information for each adjustment bolt 30 in the direction in which the multiple adjustment bolts 30 arranged on the die 20 are aligned, calculated based on the presence or absence of the adjustment bolts 30 detected while moving the laser displacement sensor 70 in the width direction Y, is referred to as the "bolt position recipe." Before the extrusion molding apparatus 1 manufactures the resin film F, the thickness adjustment device 100 calculates the position of each adjustment bolt 30 based on the detection results of the laser displacement sensor 70 using the control device 80, and creates a bolt position recipe. The bolt position recipe, for example, indicates the position of each adjustment bolt 30 in the width direction Y from a reference position within the movement range of the rotating device 50. The created bolt position recipe is stored in the storage unit of the control device 80.

Next, the operation of the extrusion molding apparatus 1 according to this embodiment and the method for adjusting the thickness of the resin film F will be described. When manufacturing the resin film F with the extrusion molding apparatus 1, the resin material for the resin film F, such as pelletized resin, is fed into the extruder 11 and melted within the extruder 11. The molten resin in the extruder 11 is extruded toward the die 20.

The molten resin extruded from the extruder 11 is fed into the die 20 through the input section 21 formed on the upper surface of the die 20. The molten resin fed into the die 20 flows through the vertical channel 22a of the introduction channel 22 to the horizontal channel 22b, where it spreads out in the width direction Y of the die 20. The molten resin flowing in the horizontal channel 22b flows into the slit 25 connected to the horizontal channel 22b, where it becomes a thin film and is discharged from the slit 25 toward the lower side of the die 20. In other words, the molten resin is discharged from the slit 25 formed in the die 20 in the form of a thin resin film F.

The unsolidified resin film F, discharged from the slit 25, comes into contact with the cast roll 13 located below the die 20 and is cooled while being conveyed by the cast roll 13. This solidifies the resin film F, which was in a molten state before solidification. The resin film F, solidified by the cast roll 13, is then conveyed downstream in the conveying direction by the conveying roll 14.

A thickness gauge 15 is positioned along the transport path of the resin film F being conveyed in this manner. The thickness gauge 15 measures the thickness of the resin film F that has been discharged from the slit 25 of the die 20 and solidified by the cast roll 13. At this time, the thickness gauge 15 measures the thickness of the resin film F at multiple positions in the width direction of the resin film F. After measuring the thickness of the resin film F, the thickness gauge 15 outputs the measured thickness to the control device 80. The control device 80 stores the thickness measured by the thickness gauge 15 for each position in the width direction of the resin film F.

The resin film F, whose thickness has been measured by the thickness gauge 15, is transported by the transport roll 14 to the position of the winding machine 16, where it is wound up by the winding machine 16.

When manufacturing the resin film F in the extrusion molding apparatus 1, the thickness of the resin film F is measured using the thickness gauge 15 as described above. The thickness adjustment device 100 adjusts the spacing of the slits 25 formed in the die 20 based on the measured thickness. Specifically, the thickness adjustment device 100 adjusts the spacing of the slits 25 by adjusting the pressing force applied to the lip portion 23 by multiple adjustment bolts 30 positioned on the die 20, based on the measured thickness of the resin film F. The adjustment of the slit spacing 25 is performed by pre-calculating the position of each adjustment bolt 30 before manufacturing the resin film F in the extrusion molding apparatus 1, and using a pre-created bolt position recipe.

The thickness adjustment device 100 adjusts the spacing of the slits 25 based on the thickness of the resin film F at each position in the width direction Y, as measured by the thickness gauge 15. In other words, when adjusting the spacing of the slits 25, the thickness adjustment device 100 adjusts the spacing of the slits 25 by fitting the socket 53 of the rotating device 50 onto the adjustment bolt 30 and rotating the adjustment bolt 30, based on the position of each adjustment bolt 30 calculated by the control device 80.

For example, if the thickness of the resin film F at a certain position in the width direction exceeds a predetermined thickness, the pressing force of the die 20 against the lip portion 23 is increased by the adjustment bolt 30, which is positioned in the width direction Y of the slit 25 corresponding to the thickened portion. This narrows the spacing of the slit 25 in the portion of the resin film F corresponding to the thickened portion, thereby reducing the thickness of the thickened portion of the resin film F.

Conversely, if the thickness of the resin film F at a certain position in the width direction is thinner than a predetermined thickness, the pressing force of the die 20 against the lip portion 23 is reduced by the adjustment bolt 30, which is positioned in the width direction Y of the slit 25 corresponding to the thin portion. This widens the spacing of the slit 25 in the portion of the resin film F corresponding to the portion where the thickness is thinner than the predetermined thickness, thereby increasing the thickness of the thin portion of the resin film F.

The spacing of the slits 25 is adjusted by adjusting the pressing force of the adjustment bolt 30 against the lip portion 23, which is performed by the automatic adjustment device 40. The automatic adjustment device 40 is controlled by the control device 80. The control device 80 operates the traveling device 60 by controlling it via the control unit 45 of the automatic adjustment device 40, thereby moving the rotating device 50 in the width direction Y. This moves the rotating device 50 in the width direction Y so that the socket 53 of the rotating device 50 is positioned in the width direction Y of the adjustment bolt 30 that adjusts the pressing force.

The movement of the rotating device 50 in the width direction Y by the traveling device 60 is performed using a pre-created bolt position recipe. Since the bolt position recipe calculates the position of each adjustment bolt 30 in the width direction Y with high precision based on the detection results from the laser displacement sensor 70, the control device 80 can move the rotating device 50 to the desired adjustment bolt 30 position with high precision by controlling the traveling device 60 using the bolt position recipe.

Once the rotating device 50 has been moved to the position where the target adjustment bolt 30 is located in the width direction Y, the control device 80 controls the rotating device actuator 51 of the rotating device 50 to extend the shaft portion 52 and fit the socket 53 onto the bolt head 30a of the adjustment bolt 30.

Once the socket 53 of the rotating device 50 is fitted onto the bolt head 30a, the control device 80 rotates the shaft 52 by operating the rotating device actuator 51, thereby rotating the adjustment bolt 30 into which the socket 53 is fitted. This adjusts the pressing force applied by the adjustment bolt 30 against the lip portion 23 of the die 20, and adjusts the spacing of the slits 25 at the position where the adjustment bolt 30 is located in the width direction Y.

Here, since both the fitting hole 53a formed in the socket 53 of the rotating device 50 and the bolt head 30a of the adjustment bolt 30 are formed in a substantially regular hexagonal shape, if the orientation of the regular hexagons of the socket 53 and the bolt head 30a are different in the direction of rotation, the socket 53 cannot be fitted onto the bolt head 30a. In other words, if the phase difference between the socket 53 and the bolt head 30a in the direction of rotation is greater than what can be tolerated by the gap between the fitting hole 53a and the bolt head 30a, the two cannot be fitted together. In this case, the control device 80 repeatedly rotates the shaft portion 52 of the rotating device 50 little by little to rotate the socket 53 until the socket 53 is fitted onto the bolt head 30a.

In other words, when the control device 80 instructs the rotating device actuator 51 to extend the shaft 52 of the rotating device 50 to fit the socket 53 onto the bolt head 30a, if the socket 53 abuts against the bolt head 30a and prevents the shaft 52 from extending beyond a certain point, the control device 80 determines that the socket 53 and the bolt head 30a are out of phase in the rotational direction. If the control device 80 determines that the socket 53 and the bolt head 30a are out of phase in the rotational direction, it temporarily retracts the shaft 52, rotates it slightly, and then extends the shaft 52 again to fit the socket 53 onto the bolt head 30a.

If the control device 80 determines that the rotational phases of the socket 53 and the bolt head 30a are different, it will, for example, retract the shaft 52, rotate it by approximately 1°, and then repeat the operation to fit the socket 53 onto the bolt head 30a. The control device 80 will cause the rotating device 50 to repeat this operation until the socket 53 is fitted onto the bolt head 30a.

When adjusting the spacing of the slits 25, the control device 80 adjusts the spacing of the slits 25 by fitting the socket 53 of the rotating device 50 onto the adjustment bolt 30 and rotating the adjustment bolt 30, based on the calculated position of each adjustment bolt 30. In other words, based on the detection result of the resin film F by the thickness gauge 15, the control device 80 causes the automatic adjustment device 40 to perform these operations, thereby rotating the desired adjustment bolt 30 from among the multiple adjustment bolts 30 arranged on the die 20 to adjust the thickness of the resin film F.

During the production of the resin film F using the extrusion molding apparatus 1, heated and molten resin is supplied from the extruder 11 to the die 20, and then extruded in a thin film form through the slit 25 of the die 20. Because heated resin is supplied to the die 20 in this way, the temperature of the die 20 also rises. When the temperature of the die 20 rises, the thermal expansion of the die 20 may cause a change in the distance of the multiple adjustment bolts 30 positioned on the die 20 from their reference positions.

Therefore, after the extrusion molding apparatus 1 starts manufacturing the resin film F, the thickness adjustment device 100 periodically calculates the position of each adjustment bolt 30 using the control device 80 and updates the bolt position recipe. In this case, the calculation of the position of each adjustment bolt 30 is performed using the same method as the calculation performed by the thickness adjustment device 100 before the extrusion molding apparatus 1 manufactures the resin film F.

The thickness adjustment device 100 periodically updates the bolt position recipe after the extrusion molding device 1 has started manufacturing the resin film F. When adjusting the spacing of the slits 25, it uses the updated bolt position recipe to rotate the desired adjustment bolt 30 using the rotating device 50. This allows the socket 53 of the rotating device 50 to be appropriately moved to the position of the adjustment bolt 30, even if the position of the adjustment bolt 30 changes slightly compared to before the start of resin film F manufacturing due to thermal expansion of the die 20 during the manufacturing of the resin film F by the extrusion molding device 1.

Therefore, even if the position of the adjustment bolt 30 changes slightly compared to before the start of manufacturing the resin film F, the adjustment bolt 30 can be rotated by the rotating device 50, and the spacing of the slits 25 can be appropriately adjusted.

The thickness adjustment device 100 according to the above embodiment detects the presence or absence of adjustment bolts 30 using a laser displacement sensor 70 that moves together with a rotating device 50 that rotates multiple adjustment bolts 30 arranged on the die 20. Based on the detection result of the laser displacement sensor 70, the control device 80 calculates the position of each adjustment bolt 30 in the direction in which the multiple adjustment bolts 30 are aligned. Therefore, when the rotating device 50 that rotates the adjustment bolts 30 that adjust the spacing of the slits 25 is moved by the traveling device 60 in the direction in which the multiple adjustment bolts 30 are aligned, the device is moved based on the position of each adjustment bolt 30 calculated by the control device 80, allowing the rotating device 50 to be moved to the desired position of the adjustment bolt 30 with high precision. Consequently, when adjusting the pressing force of the adjustment bolts 30 against the lip portion 23 of the die 20 to adjust the spacing of the slits 25, the socket 53 of the rotating device 50 can be fitted onto the desired adjustment bolt 30, and the rotating device 50 can rotate the desired adjustment bolt 30. As a result, the thickness of the resin film F can be easily adjusted.

Furthermore, the thickness adjustment device 100's laser displacement sensor 70's movement speed and bolt position acquisition time are set to ensure that the discrepancy between the position of the adjustment bolt 30 calculated by the control device 80 and the actual position of the adjustment bolt 30 is within the allowable gap between the socket 53 and the adjustment bolt 30 when the socket 53 is fitted onto the adjustment bolt 30. This allows the rotating device 50 to be moved in the width direction Y based on the position of the adjustment bolt 30 calculated by the control device 80, and the socket 53 of the rotating device 50 to be fitted onto the adjustment bolt 30. Therefore, when adjusting the pressing force of the adjustment bolt 30 against the lip portion 23 of the die 20 to adjust the spacing of the slits 25, the target adjustment bolt 30 can be rotated by the rotating device 50. As a result, the thickness of the resin film F can be easily adjusted.

Furthermore, since a laser displacement sensor 70 is used in the bolt detection unit, which moves together with the rotating device 50 via the traveling device 60 to detect the presence or absence of the adjustment bolt 30 in the direction of movement, the adjustment bolt 30 can be appropriately detected even if the distance from the adjustment bolt 30 to the laser displacement sensor 70 changes. In other words, since the adjustment bolt 30 adjusts the spacing of the slits 25 in the die 20 by moving axially, the distance from the laser displacement sensor 70 changes when it moves axially. On the other hand, since the laser displacement sensor 70 detects the adjustment bolt 30 using laser light L, there is no need to focus when detecting the adjustment bolt 30, and the tolerance range for distance when detecting the adjustment bolt 30 is large. Therefore, the laser displacement sensor 70 can appropriately detect the adjustment bolt 30 regardless of its axial position when moving axially, and it is possible to rotate the target adjustment bolt 30 by the rotating device 50 when adjusting the spacing of the slits 25. As a result, the thickness of the resin film F can be easily adjusted.

Furthermore, the thickness adjustment method according to this embodiment involves measuring the thickness of the resin film F during its manufacture and adjusting the spacing of the slits 25 by adjusting the pressing force applied to the lip portion 23 using the adjustment bolts 30 based on the measured thickness of the resin film F. At this time, the position of each adjustment bolt 30 in the direction in which the adjustment bolts 30 are aligned is calculated in advance based on the detection results from the laser displacement sensor 70. Based on the calculated positions of each adjustment bolt 30, the socket 53 of the rotating device 50 is fitted onto the adjustment bolt 30, and the adjustment bolt 30 is rotated to adjust the spacing of the slits 25. This allows the spacing of the slits 25 to be adjusted by rotating the desired adjustment bolt 30 during the manufacture of the resin film F. As a result, the thickness of the resin film F can be easily adjusted.

[Variations]
In the above-described embodiment, the control device 80, which calculates the position of each adjustment bolt 30 based on the detection result of the adjustment bolt 30 by the laser displacement sensor 70, and the control unit 45, which controls the operation of the automatic adjustment device 40, are provided independently of each other. However, both functions may be realized by a single device. For example, the control unit 45 that controls the operation of the automatic adjustment device 40 may also be provided as a bolt position calculation unit, and the position of each adjustment bolt 30 in the direction in which the multiple adjustment bolts 30 are lined up may be calculated based on the detection result of the adjustment bolt 30 by the laser displacement sensor 70.

This allows the distance between the control unit 45, which calculates the position of each adjustment bolt 30, and the laser displacement sensor 70 to be shortened, thereby reducing the communication delay between the laser displacement sensor 70 and the control unit 45. Consequently, as the communication delay between the laser displacement sensor 70 and the control unit 45 is reduced, the communication lag D can be reduced, and the discrepancy between the position of the adjustment bolt 30 calculated by the control unit 45 and the actual position of the adjustment bolt 30 can be reduced. As a result, the thickness of the resin film F can be easily adjusted.

Furthermore, in the above-described embodiment, a laser displacement sensor 70 is used as a bolt detection unit that moves together with the rotating device 50 by the traveling device 60 to detect the presence or absence of the adjustment bolt 30 in the direction of movement. However, a device other than the laser displacement sensor 70 may be used for the bolt detection unit. For example, a camera that outputs captured video as an electrical signal may be used for the bolt detection unit. By using a camera for the bolt detection unit, not only the position of the adjustment bolt 30 but also the phase of the bolt head 30a of the adjustment bolt 30 in the direction of rotation can be detected from the captured image data.

This allows the rotational phase of the socket 53 of the rotating device 50 to be pre-rotated to match the rotational phase of the bolt head 30a before fitting the socket 53 onto the bolt head 30a. Therefore, the socket 53 can be easily fitted onto the bolt head 30a. Consequently, the spacing of the slits 25 can be easily adjusted by adjusting the pressing force applied from the adjustment bolt 30 to the lip portion 23 of the die 20, and the thickness of the resin film F can be easily adjusted.

Furthermore, in the above-described embodiment, the rotating device 50 has a fitting portion formed by a socket 53, and the socket 53 can be fitted onto the adjustment bolt 30 by fitting the socket 53 onto the bolt head 30a of the adjustment bolt 30 from the outside. However, the fitting portion may be configured to be fitted onto the adjustment bolt 30 in other ways. For example, a substantially hexagonal hole may be formed in the bolt head 30a of the adjustment bolt 30, and the fitting portion of the rotating device 50 may be formed in a rod shape with a substantially hexagonal cross-section when viewed in the axial direction, and the fitting portion may be configured to be fitted onto the adjustment bolt 30 by being inserted into the hole formed in the bolt head 30a. The form of fitting is not limited as long as the fitting portion of the rotating device 50 can be fitted onto the adjustment bolt 30 and rotate the adjustment bolt 30.

1 Extrusion molding apparatus 11 Extruder 12 Supply member 13 Cast roll 14 Conveyor roll 15 Thickness gauge 16 Winding machine 20 Die 21 Input section 22 Inlet channel 22a Vertical channel 22b Horizontal channel 23 Lip section 23a Fixed side lip 23b Movable side lip 25 Slit 30 Adjustment bolt 30a Bolt head 31 Bolt support section 40 Automatic adjustment device 41 Adjustment device support section 45 Control unit 50 Rotating device 51 Rotating device actuator 52 Shaft section 53 Socket 53a Fitting hole 60 Traveling device 61 Traveling device actuator 62 Rotating device support section 63 Traveling rail 64 Belt 70 Laser displacement sensor (bolt detection section)
80 Control device (bolt position calculation unit)
100 Thickness adjustment device

Claims (2)

A die that extrudes a resin film from a slit formed between a pair of separated lip portions,
Multiple adjustment bolts are arranged in a line along the extending direction of the lip portion, and the spacing between the slits is adjusted by applying a pressing force to the lip portion.
A rotating device having a fitting portion that engages with the adjustment bolt, and which rotates the adjustment bolt by fitting the fitting portion onto the adjustment bolt,
A traveling device that moves the rotating device along the direction in which the multiple adjustment bolts are aligned,
A bolt detection unit moves together with the rotating device via the aforementioned traveling device and detects the presence or absence of the adjustment bolt in the direction of movement,
A bolt position calculation unit calculates the position of each adjustment bolt in the direction in which multiple adjustment bolts are aligned, based on the detection result of the adjustment bolts by the bolt detection unit.
Equipped with ,
The moving speed of the bolt detection unit by the traveling device and the bolt position acquisition time, which is the time required from the detection of the presence or absence of the adjustment bolt by the bolt detection unit until the position of the adjustment bolt is calculated by the bolt position calculation unit, are
The bolt detection unit, which detects the presence or absence of the adjustment bolt while moving with the aforementioned traveling device, transmits the detection result to the bolt position calculation unit via communication, and the difference between the position of the adjustment bolt calculated by the bolt position calculation unit and the actual position of the adjustment bolt is,
A thickness adjustment device having a moving speed and a bolt position acquisition time such that the moving speed and bolt position acquisition time are within the range of the allowable gap between the fitting portion and the adjustment bolt that is permitted when the fitting portion is fitted onto the adjustment bolt. A procedure for measuring the thickness of a resin film discharged from a slit in a die having a slit formed between a pair of separated lip portions,
A procedure for adjusting the spacing of the slits by adjusting the pressing force applied to the lip portion using adjustment bolts arranged in a row along the extending direction of the lip portion, based on the measured thickness of the resin film,
A thickness adjustment method including,
Based on the detection results from a bolt detection unit that moves along the direction in which the multiple adjustment bolts are aligned together with a rotating device that rotates the adjustment bolts and detects the presence or absence of the adjustment bolts in the direction of movement, a bolt position calculation unit calculates the position of each adjustment bolt in the direction in which the adjustment bolts are aligned, and pre-calculates the position of each adjustment bolt .
When adjusting the spacing of the slits, the spacing of the slits is adjusted by fitting the fitting portion of the rotating device onto the adjustment bolt and rotating the adjustment bolt based on the position of each adjustment bolt calculated by the bolt position calculation unit .
When calculating the position of each adjustment bolt, the moving speed of the bolt detection unit and the bolt position acquisition time, which is the time required from the detection of the presence or absence of the adjustment bolt by the bolt detection unit until the bolt position calculation unit calculates the position of the adjustment bolt, are:
The bolt detection unit detects the presence or absence of the adjustment bolt while moving, and the detection result is transmitted via communication to the bolt position calculation unit. The difference between the position of the adjustment bolt calculated by the bolt position calculation unit and the actual position of the adjustment bolt is then determined.
A thickness adjustment method in which the moving speed and the bolt position acquisition time are such that the moving speed and bolt position acquisition time are within the range of the allowable gap between the fitting portion and the adjustment bolt that is permitted when the fitting portion is fitted onto the adjustment bolt.