JP7275810B2 - Extrusion die and lip gap measurement method - Google Patents

Description

The present invention relates to extrusion dies and methods for measuring lip gaps.

2. Description of the Related Art As an apparatus for manufacturing a sheet made of thermoplastic resin, an extrusion molding apparatus equipped with a die for molding resin is known. In an extrusion apparatus, the die has a pair of lips. The molten resin is discharged from between the pair of lips to form a sheet of resin. Patent Literature 1 describes an example of an extrusion molding apparatus. In Patent Literature 1, it is possible to adjust the clearance of the discharge port with an adjustment bolt. In addition, the adjustment bolt is driven based on the detection result of the proximity sensor that detects the gap size of the ejection port, and the gap size of the ejection port is adjusted.

JP 2014-19079 A

By the way, it is required to improve the thickness accuracy of the sheet and to shorten the time required for adjusting the thickness of the sheet. For this purpose, it is necessary to calculate the lip gap (gap between ejection ports) with high accuracy. However, in the configuration of Patent Document 1, there is a limit to improving the accuracy of calculating the lip gap.

The present disclosure has been made in view of the above problems, and an object thereof is to provide an extrusion molding die and a lip gap measuring method that can improve the accuracy of lip gap calculation.

In order to achieve the above object, the extrusion molding die of one aspect of the present disclosure includes a first die body, a second die body facing the first die body across a molten resin flow path, and the a first lip arranged at the end of the first die body; a second lip arranged at the end of the second die body and facing the first lip across the molten resin discharge port; An adjustment device provided on the die body for changing a lip gap that is the width of the discharge port in the lateral direction, a first detector for detecting displacement of the first lip, and a displacement for detecting the displacement of the second lip. and a second detector.

When the molten resin is being discharged from the discharge port, both the first lip and the second lip may be deformed by the pressure of the molten resin. If the lip gap is calculated based on the displacement of one of the first lip and the second lip, the lip gap may not be calculated accurately. Moreover, it is difficult to directly measure the lip gap with high accuracy while the molten resin is being discharged from the discharge port. In contrast, in the present disclosure, the first detector and the second detector can calculate the lip gap based on both the displacement of the first lip and the displacement of the second lip. Therefore, the extrusion die of the present disclosure can improve the calculation accuracy of the lip gap. As a result, the extrusion die of the present disclosure can improve sheet thickness accuracy. The extrusion die of the present disclosure can shorten the time required to adjust the thickness of the sheet.

As one aspect of the extrusion molding die of the present disclosure, a plurality of the adjustment devices arranged along the longitudinal direction of the discharge port, and a plurality of the first detectors arranged along the longitudinal direction of the discharge port and a plurality of the second detectors arranged along the longitudinal direction of the ejection port, wherein the position of the first detector in the longitudinal direction of the ejection port corresponds to the position of the ejection port of the adjusting device. It is desirable that there is one-to-one correspondence with the position in the longitudinal direction, and that the position of the discharge port of the second detector in the longitudinal direction corresponds one-to-one with the position of the discharge port of the adjustment device in the longitudinal direction. .

Thereby, the displacement of the first lip and the displacement of the second lip can be measured at a plurality of locations in the longitudinal direction of the ejection port. Therefore, the extrusion die of the present disclosure can improve the calculation accuracy of the lip gaps at multiple locations. In addition, the lip gap can be adjusted by each adjustment device at a plurality of locations in the longitudinal direction of the ejection port. Therefore, the extrusion die of the present disclosure can further improve the thickness accuracy of the sheet.

As one aspect of the extrusion molding die of the present disclosure, it is desirable that the first detector and the second detector are arranged in a direction opposite to the direction of ejection of the molten resin with respect to the ejection port.

Other devices such as rolls may be arranged in the direction of ejection of the molten resin with respect to the extrusion die. The extrusion die can suppress interference between other devices placed near the extrusion die and the first detector and the second detector.

In one aspect of the extrusion die of the present disclosure, the first lip comprises a first detection surface facing the first detector and the second lip comprises a second detection surface facing the second detector. It is preferable that the first detection surface and the second detection surface are planes that form an angle with respect to the direction of ejection of the molten resin and face the direction opposite to the direction of ejection of the molten resin.

Thereby, the first detector can detect the displacement of the first lip and can be arranged so as to extend in the direction opposite to the ejection direction of the molten resin. The second detector can detect the displacement of the second lip, and can be arranged so as to extend in the direction opposite to the direction of ejection of the molten resin. Therefore, the extrusion die of the present disclosure can suppress interference between other devices arranged near the extrusion die and the first detector and the second detector.

In one aspect of the extrusion die of the present disclosure, the first lip comprises a first detection surface facing the first detector and the second lip comprises a second detection surface facing the second detector. It is desirable that the first detection surface and the second detection surface are planes parallel to the ejection direction of the molten resin.

Thereby, the first detector can detect the displacement of the first lip in the lateral direction of the ejection port. The second detector can detect displacement of the second lip in the lateral direction of the ejection port. Extrusion dies of the present disclosure can facilitate lip gap calculations.

As one aspect of the extrusion molding die of the present disclosure, a first connecting member arranged at one end of the first die body in the longitudinal direction of the discharge port and connecting the first die body and the second die body; a second connecting member disposed at the other end of the first die body in the longitudinal direction of the discharge port and connecting the first die body and the second die body; a first supporting member arranged on the opposite side of the die body and supported by the first connecting member and the second connecting member; and arranged on the opposite side of the second die body from the first die body. and a second support member supported by the first connection member and the second connection member, wherein the first detector is supported by the first support member, and the second detector is supported by the It is desirable to be supported by a second support member.

As a result, the position of the first detector is less susceptible to deformation of the first lip than when the first detector is fixed to the first die body. Therefore, the accuracy of displacement of the first lip detected by the first detector is improved. Also, compared to the case where the second detector is fixed to the second die body, the position of the second detector is less susceptible to deformation of the second lip. Therefore, the accuracy of displacement of the second lip detected by the second detector is improved. Therefore, the extrusion die of the present disclosure can further improve the calculation accuracy of the lip gap.

In order to achieve the above object, a method for measuring a lip gap of one aspect of the present disclosure is a method for measuring a lip gap of an extrusion die, wherein the extrusion die includes a first die body and a molten resin a second die body facing the first die body across the flow path, a first lip disposed at the end of the first die body, and a melt disposed at the end of the second die body a second lip facing the first lip across the resin discharge port; an adjusting device provided on the second die body for changing a lip gap that is the width of the discharge port in the lateral direction; Equipped with a first detector that detects displacement of one lip and a second detector that detects displacement of the second lip, the short side of the ejection port in an initial state in which the molten resin is not ejected from the ejection port an initial measuring step of measuring an initial lip gap that is the width of a direction; said initial lip gap; displacement of said first lip detected by said first detector; and displacement of said second lip detected by said second detector. and a lip gap calculation step of calculating the lip gap based on the displacement of

By calculating the lip gap based on both the displacement of the first lip and the displacement of the second lip, the lip gap measurement method of the present disclosure can improve the calculation accuracy of the lip gap.

As one aspect of the lip gap measuring method of the present disclosure, in a state in which the molten resin is discharged from the discharge port, the first detector detects the displacement of the first lip in the lateral direction of the discharge port. A first constant representing the relationship with the displacement of the first lip, and a relationship between the displacement of the second lip in the lateral direction of the discharge port and the displacement of the second lip detected by the second detector. the initial lip gap; the displacement of the first lip detected by the first detector; the first constant; and the first constant detected by the second detector. It is desirable to include the lip gap calculating step of calculating the lip gap based on two lip displacements and the second constant.

Thereby, even if the displacement detected by the first detector and the second detector is not the displacement in the lateral direction of the ejection port, the lip gap can be calculated with high accuracy. Moreover, the directions of the first detection surface as the detection target of the first detector and the orientation of the second detection surface as the detection target of the second detector are not limited. Therefore, it is easy to arrange the first detector and the second detector.

ADVANTAGE OF THE INVENTION According to this invention, the calculation precision of a lip gap can be improved.

FIG. 1 is a schematic diagram of an extrusion molding apparatus according to this embodiment. FIG. 2 is a front view of the extrusion die of this embodiment. FIG. 3 is an enlarged front view of the first lip and the second lip of this embodiment. FIG. 4 is a left side view of the extrusion die of this embodiment. FIG. 5 is a plan view of the extrusion die of this embodiment. FIG. 6 is a schematic diagram of the control device of this embodiment. FIG. 7 is a flow chart of the lip gap measuring method of this embodiment. FIG. 8 shows the relationship between the displacement of the first lip in the lateral direction of the ejection port and the displacement of the first lip detected by the first detector, and the displacement of the second lip in the lateral direction of the ejection port and the second detection. 4 is a graph showing the relationship with the displacement of the second lip detected by the device.

Hereinafter, the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, components in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those that fall within a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be combined as appropriate.

(embodiment)
FIG. 1 is a schematic diagram of an extrusion molding apparatus according to this embodiment. FIG. 2 is a front view of the extrusion die of this embodiment. FIG. 3 is an enlarged front view of the first lip and the second lip of this embodiment. FIG. 4 is a left side view of the extrusion die of this embodiment. FIG. 5 is a plan view of the extrusion die of this embodiment. FIG. 6 is a schematic diagram of the control device of this embodiment.

An extrusion molding apparatus 100 of this embodiment is an apparatus for producing a sheet using a synthetic resin. Extruder 100 is an apparatus for producing single-layer sheets. A single-layer sheet is a sheet formed from one kind of raw material. In addition, the extrusion molding apparatus 100 may be an apparatus for producing a multilayer sheet.

As shown in FIG. 1 , the extrusion molding device 100 includes an extruder 11 , an extrusion molding die 20 , a cooling roll 13 , a heating device 15 , a thickness measuring device 17 and a control device 90 .

The extruder 11 is a device that extrudes molten resin toward an extrusion die 20 . Resin is supplied as a material to the hopper of the extruder 11 . The resin supplied to the hopper is heated and kneaded in advance and formed into pellets. The pelletized resin is led from the hopper to the cylinder of the extruder 11 . The cylinder is provided with a screw. The resin is melted by the screw and extruded towards the extrusion die 20 .

The extrusion molding die 20 is a device for molding molten resin into a sheet. A molten resin is supplied from the extruder 11 to the upper side of the extrusion die 20 . The molten resin moves downward inside the extrusion die 20 and is discharged from the lower end of the extrusion die 20 .

As shown in FIGS. 2 to 5, the extrusion die 20 includes a first die body 21, a second die body 22, a first connecting member 25, a second connecting member 26, and a first supporting member 28. , a second support member 29 , a first lip 31 , a second lip 32 , an adjusting device 43 , a first detector 41 and a second detector 42 . Note that the first detector 41 and the second detector 42 are omitted in FIG.

As shown in FIG. 2, the first die body 21 and the second die body 22 are arranged with a flow path 23 through which the molten resin flows. The side surface of the second die body 22 faces the side surface of the first die body 21 across the flow path 23 . The channel 23 includes an introduction channel 23a, a manifold 23b, and a discharge channel 23c. The introduction channel 23a is a hole extending in the vertical direction. The manifold 23b is connected to the lower end of the introduction channel 23a. Manifold 23b extends horizontally. The molten resin flowing through the introduction channel 23a spreads horizontally when reaching the manifold 23b. The discharge channel 23c is connected to the lower end of the manifold 23b. A discharge port 35, which is an opening, is provided at the lower end of the discharge channel 23c. The molten resin that has passed through the introduction channel 23a, the manifold 23b, and the discharge channel 23c is discharged downward from the discharge port 35. As shown in FIG.

In the following description, XYZ orthogonal coordinate axes are used. The X-axis is parallel to the lateral direction of the ejection port 35 . The Y-axis is parallel to the longitudinal direction of the ejection port 35 . The Z-axis is parallel to the ejection direction of the molten resin from the ejection port 35 . A direction parallel to the X-axis is described as the X-direction. A direction parallel to the Y-axis is described as the Y-direction. A direction parallel to the Z-axis is described as the Z-direction. The direction from the second die body 22 toward the first die body 21 is defined as +X direction. The discharge direction of the molten resin (the direction from the introduction channel 23a to the discharge channel 23c) is defined as +Z direction. The +Y direction is the left direction when the -Z direction is the top and the +X direction is oriented.

As shown in FIGS. 4 and 5, the first connecting member 25 is arranged at the end of the first die body 21 in the -Y direction. The first connecting member 25 is fixed to the first die body 21 and the second die body 22 by fixing members. The fixing member is, for example, a bolt. The first connecting member 25 connects the first die body 21 and the second die body 22 .

As shown in FIGS. 4 and 5 , the second connecting member 26 is arranged at the +Y direction end of the first die body 21 and the second die body 22 . The second connecting member 26 is fixed to the first die body 21 and the second die body 22 by fixing members. The fixing member is, for example, a bolt. The second connecting member 26 connects the first die body 21 and the second die body 22 .

As shown in FIG. 5 , the first support member 28 is arranged in the +X direction with respect to the first die body 21 . The first support member 28 is arranged on the side opposite to the second die body 22 with respect to the first die body 21 . The first support member 28 is fixed to the first connecting member 25 and the second connecting member 26 by fixing members. The fixing member is, for example, a bolt. The first supporting member 28 is supported by the first connecting member 25 and the second connecting member 26 .

As shown in FIG. 5, the second support member 29 is arranged in the -X direction with respect to the second die body 22 . The second support member 29 is arranged on the side opposite to the first die body 21 with respect to the second die body 22 . The second support member 29 is fixed to the first connecting member 25 and the second connecting member 26 by fixing members. The fixing member is, for example, a bolt. The second support member 29 is supported by the first connecting member 25 and the second connecting member 26 .

As shown in FIG. 2 , the first lip 31 is arranged at the +Z direction end of the first die body 21 . As shown in FIG. 3, the first lip 31 has a first detection surface 31a and a first auxiliary detection surface 31b. The first detection surface 31a is a plane that forms an angle θ1 with respect to the Z direction when viewed from the Y direction. The first detection surface 31a forms an angle θ1 with respect to the YZ plane and is perpendicular to the XZ plane. The angle θ1 is, for example, 50°. The first detection surface 31a faces the +X direction and the -Z direction. The first detection surface 31a is arranged in the −Z direction with respect to the ejection port 35. As shown in FIG. The first auxiliary detection surface 31b is a plane parallel to the YZ plane. The first auxiliary detection surface 31b is arranged between the ejection port 35 and the first detection surface 31a in the Z direction.

As shown in FIG. 2 , the second lip 32 is arranged at the +Z direction end of the second die body 22 . The second lip 32 faces the first lip 31 across the discharge port 35 . As shown in FIG. 3, the second lip 32 has a second detection surface 32a and a second auxiliary detection surface 32b. The second detection surface 32a is a plane that forms an angle θ2 with respect to the Z direction when viewed from the Y direction. The second detection surface 32a forms an angle θ2 with respect to the YZ plane and is perpendicular to the XZ plane. The angle θ2 is, for example, 45°. The second detection surface 32a faces the -X direction and the -Z direction. The second detection surface 32a is arranged in the -Z direction from the ejection port 35. As shown in FIG. The second auxiliary detection surface 32b is a plane parallel to the YZ plane. The second auxiliary detection surface 32b is arranged between the ejection port 35 and the second detection surface 32a in the Z direction. When viewed from the X direction, the second auxiliary detection surface 32b overlaps the first auxiliary detection surface 31b.

As shown in FIG. 3, the first lip 31 and the second lip 32 adjacent in the X direction form a discharge port 35. As shown in FIG. A lip gap G, which is the width of the discharge port 35 in the X direction, changes depending on the relative positions of the first lip 31 and the second lip 32 .

The adjusting device 43 is a device for changing the lip gap G. As shown in FIG. As shown in FIG. 2, the adjustment device 43 is an adjustment bolt. The adjustment device 43 is provided on the second die body 22 . One end of the adjustment device 43 protrudes from the second die body 22 . The other end of the adjusting device 43 is attached to the second lip 32 . When one end of the adjusting device 43 is rotated, the other end moves and the second lip 32 elastically deforms. The adjusting device 43 pushes and pulls the second lip 32 . Thereby, the lip gap G changes. The adjustment device 43 preferably has a heater. The heater makes it possible to expand and contract the adjustment device 43 . Fine adjustment of the lip gap G is facilitated by providing the adjustment device 43 with a heater.

As shown in FIG. 4, extrusion die 20 includes a plurality of adjustment devices 43 . A plurality of adjustment devices 43 are arranged at regular intervals along the Y direction. A plurality of adjusting devices 43 can adjust the lip gap G at a plurality of positions in the Y direction.

The first detector 41 is a device that detects displacement of the first lip 31 . The first detector 41 is a displacement sensor. The first detector 41 is, for example, a contact-type displacement sensor. The type of displacement sensor used as the first detector 41 is not particularly limited, and may be a capacitance type, an optical fiber type, or the like. As shown in FIG. 2, the first detector 41 is arranged in the -Z direction with respect to the ejection port 35 . The first detector 41 is supported by the first support member 28 . The first detector 41 faces the first detection surface 31a. The first detector 41 detects displacement of the first detection surface 31a. The displacement detected by the first detection surface 31a is the displacement of the first detection surface 31a in the direction orthogonal to the first detection surface 31a when the initial state is set as a reference (zero).

The initial state is a state in which the molten resin is not discharged from the discharge port 35 . The initial state is desirably a state in which the extrusion molding die 20 is heated to a predetermined temperature. The predetermined temperature is the temperature at which the molten resin is discharged from the discharge port 35 .

The extrusion die 20 has a plurality of first detectors 41 . The multiple first detectors 41 are arranged at regular intervals along the Y direction. The position of the first detector 41 in the Y direction corresponds to the position of the adjustment device 43 in the Y direction on a one-to-one basis. That is, the Y-direction position of the first detector 41 is equal to the Y-direction position of the adjusting device 43 .

The second detector 42 is a device that detects displacement of the second lip 32 . The second detector 42 is a displacement sensor. The second detector 42 is, for example, a contact displacement sensor. The type of displacement sensor used as the second detector 42 is not particularly limited, and may be a capacitance type, an optical fiber type, or the like. As shown in FIG. 2, the second detector 42 is arranged in the -Z direction with respect to the ejection port 35 . The second detector 42 is supported by the second support member 29 . The second detector 42 faces the second detection surface 32a. The second detector 42 detects displacement of the second detection surface 32a. The displacement detected by the second detection surface 32a is the displacement of the second detection surface 32a in the direction orthogonal to the second detection surface 32a when the initial state is set as a reference (zero).

As shown in FIG. 4, extrusion die 20 includes a plurality of second detectors 42 . The multiple second detectors 42 are arranged at regular intervals along the Y direction. The position of the second detector 42 in the Y direction corresponds to the position of the adjusting device 43 in the Y direction on a one-to-one basis. That is, the Y-direction position of the second detector 42 is equal to the Y-direction position of the adjusting device 43 .

As shown in FIG. 1, the cooling roll 13 contacts the sheet-like resin extruded from the extrusion die 20 . The cooling roll 13 cools and solidifies the sheet-shaped resin discharged from the extrusion die 20 .

The heating device 15 heats the sheet solidified by the cooling roll 13 . The heating device 15 removes residual stress from the sheet by heating the sheet. The processing performed by the heating device 15 is called annealing.

The thickness measuring device 17 is a device that measures the thickness of the sheet that has passed through the heating device 15 . The thickness measuring device 17 measures the thickness at multiple points in the width direction of the sheet. The thickness measuring device 17 outputs the measured thickness of the sheet to the control device 90 . The sheet that has passed through the thickness measuring device 17 is wound up by a winder arranged downstream of the thickness measuring device 17 .

The control device 90 is a computer and includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input interface, and an output interface. In the control device 90, the CPU, ROM, RAM, input interface and output interface are connected to an internal bus. The functions of the control device 90 are realized by the cooperation of the CPU, ROM, RAM, input interface, and output interface.

As shown in FIG. 1, controller 90 receives information from first detector 41 , second detector 42 and thickness gauge 17 . The controller 90 makes adjustments based on the displacement of the first lip 31 received from the first detector 41 , the displacement of the second lip 32 received from the second detector 42 and the sheet thickness received from the thickness gauge 17 . Control the device 43 . The control device 90 controls a driving device that rotates the adjustment device 43 or a heater provided in the adjustment device 43 .

As shown in FIG. 6 , the control device 90 includes an input section 91 , a storage section 93 , a calculation section 95 and a control section 97 . Input unit 91 receives information from first detector 41 , second detector 42 , and thickness gauge 17 . Information received by the input unit 91 is stored in the storage unit 93 . Further, the storage unit 93 stores in advance an initial lip gap, a first constant, and a second constant. The initial lip gap is the width of the ejection port 35 in the X direction in the initial state. The first constant is a constant representing the relationship between the displacement of the first lip 31 in the X direction and the displacement of the first lip 31 detected by the first detector 41 when the molten resin is discharged from the discharge port 35. be. The second constant is a constant representing the relationship between the displacement of the second lip 32 in the X direction and the displacement of the second lip 32 detected by the second detector 42 when the molten resin is discharged from the discharge port 35. be.

The calculator 95 calculates the initial lip gap, the first constant, the displacement of the first lip 31 detected by the first detector 41, the second constant, and the displacement of the second lip 32 detected by the second detector 42. and the lip gap G is calculated based on. The initial lip gap is S, the first constant is K ₁ , the displacement of the first lip 31 detected by the first detector 41 is D ₁ , the second constant is K ₂ , the second lip 32 detected by the second detector 42 , the lip gap G is expressed by the following formula (1) _.

G ₌ S+ _K1D1 + _K2D2 ( ₁ )

The calculator 95 also calculates the draw ratio based on the sheet thickness measured by the thickness measuring device 17 and the calculated lip gap G. When the thickness of the sheet measured by the thickness measuring device 17 is T, the draw ratio (E) is expressed by the following formula (2).

E=G/T (2)

The control unit 97 controls the adjusting device 43 based on the sheet thickness measured by the thickness measuring device 17 and the draw ratio. The controller 97 controls the adjusting device 43 so that the sheet thickness approaches the desired thickness and the draw ratio approaches an appropriate value. If the draw ratio is within an appropriate range, variations in sheet thickness can be suppressed.

Note that the controller 90 does not necessarily have to use the initial lip gap, the first constant, and the second constant to calculate the lip gap G. The control device 90 may calculate the lip gap G based on the displacement of the first lip 31 detected by the first detector 41 and the displacement of the second lip 32 detected by the second detector 42 . The first detection surface 31a and the second detection surface 32a do not necessarily have to be planes forming an angle with the YZ plane. The first detection surface 31a and the second detection surface 32a may be planes parallel to the YZ plane.

FIG. 7 is a flow chart of the lip gap measuring method of this embodiment. FIG. 8 shows the relationship between the displacement of the first lip in the lateral direction of the ejection port and the displacement of the first lip detected by the first detector, and the displacement of the second lip in the lateral direction of the ejection port and the second detection. 4 is a graph showing the relationship with the displacement of the second lip detected by the device.

As shown in FIG. 7, the lip gap measurement method of this embodiment includes a heating step S11, an initial measurement step S13, a constant calculation step S15, and a lip gap calculation step S17.

The heating step S11 is a step of forming a state in which the molten resin is not discharged from the discharge port 35 and the extrusion molding die 20 is at a predetermined temperature. In the heating step S11, the extrusion molding die 20 is heated to about 200° C., for example.

The initial measurement step S13 is a step of measuring the initial lip gap. In the initial measurement step S13, the initial lip gap is measured by, for example, a capacitive displacement sensor. The type of displacement sensor for measuring the initial lip gap is not particularly limited, and may be a contact sensor, a laser displacement meter, or an image analysis sensor.

The constant calculation step S15 is a step of calculating the first constant and the second constant. In the constant calculation step S15, the displacement of the first lip 31 is measured by the first detector 41 and the displacement of the first lip 31 in the X direction is measured by the first displacement measuring device 51 while the molten resin is being discharged from the discharge port 35. measurement of the displacement of is performed simultaneously. The first displacement measuring device 51 is arranged to face the first auxiliary detection surface 31b, as shown in FIG. The first displacement measuring device 51 measures the displacement of the first auxiliary detection surface 31b. In the constant calculation step S15, the displacement of the first detection surface 31a and the displacement of the first auxiliary detection surface 31b are measured simultaneously. The first displacement measuring device 51 is, for example, an optical fiber type displacement sensor. The type of displacement sensor as the first displacement measuring device 51 is not particularly limited, and may be a capacitance type, a contact type, or the like.

In the constant calculation step S15, the displacement of the second lip 32 is measured by the second detector 42 and the displacement of the second lip 32 in the X direction is measured by the second displacement measuring device 52 while the molten resin is being discharged from the discharge port 35. measurement of the displacement of is performed simultaneously. The second displacement measuring device 52 is arranged to face the second auxiliary detection surface 32b, as shown in FIG. A second displacement measuring device 52 measures the displacement of the second auxiliary detection surface 32b. In the constant calculation step S15, the displacement of the second detection surface 32a and the displacement of the second auxiliary detection surface 32b are measured simultaneously. The second displacement measuring device 52 is, for example, an optical fiber displacement sensor. The type of displacement sensor used as the second displacement measuring device 52 is not particularly limited, and may be a capacitance type, a contact type, or the like.

FIG. 8 shows an example of measurement results in the constant calculation step S15. The plot of squares in FIG. 8 shows the relationship between the simultaneously measured displacement of the first lip 31 in the X direction and the displacement detected by the first detector 41 . The triangular plot in FIG. 8 shows the relationship between the simultaneously measured displacement of the second lip 33 in the X direction and the displacement detected by the second detector 42 .

In the constant calculation step S15, a first constant is calculated based on the slope of the straight line L1 shown in FIG. A straight line L1 is a regression line calculated based on plots of a plurality of squares in FIG. The straight line L1 is calculated by, for example, the method of least squares. The first constant is calculated as the reciprocal of the slope of the straight line L1.

In the constant calculation step S15, a second constant is calculated based on the slope of the straight line L2 shown in FIG. A straight line L2 is a regression line calculated based on a plurality of triangular plots in FIG. The straight line L2 is calculated by, for example, the method of least squares. The second constant is calculated as the reciprocal of the slope of the straight line L2.

The lip gap calculation step S17 is a step of calculating the lip gap G. FIG. In the lip gap calculation step S17, the lip gap G is calculated by combining the initial lip gap, the displacement of the first lip 31 detected by the first detector 41, the first constant, and the second lip 32 detected by the second detector 42. and a second constant. Specifically, the lip gap G is calculated by the formula (1) described above. In this embodiment, the control device 90 calculates the lip gap G. FIG.

Note that the first constant and the second constant do not necessarily have to be used to calculate the lip gap G in the lip gap calculation step S17. In the lip gap calculation step S17, the lip gap G is calculated based on the initial lip gap, the displacement of the first lip 31 detected by the first detector 41, and the displacement of the second lip 32 detected by the second detector 42. may be calculated.

As described above, the extrusion molding die 20 includes the first die body 21, the second die body 22, the first lip 31, the second lip 32, the adjusting device 43, and the first detector 41. and a second detector 42 . The second die body 22 faces the first die body 21 with the molten resin flow path 23 interposed therebetween. A first lip 31 is located at the end of the first die body 21 . The second lip 32 is arranged at the end of the second die body 22 and faces the first lip 31 across the molten resin discharge port 35 . The adjustment device 43 is provided in the second die body 22 and changes the lip gap G, which is the width of the discharge port 35 in the lateral direction (X direction). The first detector 41 detects displacement of the first lip 31 . A second detector 42 detects displacement of the second lip 32 .

When the molten resin is being discharged from the discharge port 35, both the first lip 31 and the second lip 32 may be deformed by the pressure of the molten resin. If the lip gap G is calculated based on the displacement of one of the first lip 31 and the second lip 32, the lip gap G may not be calculated accurately. Moreover, it is difficult to directly measure the lip gap G with high accuracy while the molten resin is being discharged from the discharge port 35 . In contrast, in the present embodiment, the lip gap G can be calculated based on both the displacement of the first lip 31 and the displacement of the second lip 32 by the first detector 41 and the second detector 42. . Therefore, the extrusion molding die 20 of the present embodiment can improve the calculation accuracy of the lip gap G. As a result, the extrusion molding die 20 can improve the sheet thickness accuracy. The extrusion molding die 20 can shorten the time required for adjusting the thickness of the sheet.

The extrusion molding die 20 includes a plurality of adjusting devices 43 arranged along the longitudinal direction (Y direction) of the discharge port 35 and a plurality of first adjusting devices 43 arranged along the longitudinal direction (Y direction) of the discharge port 35. A detector 41 and a plurality of second detectors 42 arranged along the longitudinal direction (Y direction) of the ejection port 35 are provided. The position of the discharge port of the first detector 41 in the longitudinal direction (Y direction) corresponds to the position of the discharge port 35 of the adjustment device 43 in the longitudinal direction (Y direction) one-to-one. The position of the discharge port 35 of the second detector 42 in the longitudinal direction (Y direction) corresponds to the position of the discharge port 35 of the adjustment device 43 in the longitudinal direction (Y direction) one-to-one.

Thereby, the displacement of the first lip 31 and the displacement of the second lip 32 can be measured at a plurality of locations in the longitudinal direction (Y direction) of the discharge port 35 . Therefore, the extrusion molding die 20 can improve the calculation accuracy of the lip gap G at a plurality of locations. In addition, the lip gap G can be adjusted by the adjusting devices 38 at a plurality of locations in the longitudinal direction (Y direction) of the discharge port 35 . Therefore, the extrusion molding die 20 of this embodiment can further improve the thickness accuracy of the sheet.

In the extrusion molding die 20, the first detector 41 and the second detector 42 are arranged in the opposite direction (-Z direction) to the ejection direction of the molten resin with respect to the ejection port .

Other devices, such as rolls, may be arranged in the ejection direction of the molten resin with respect to the extrusion molding die 20 . The extrusion die 20 can suppress interference between other devices arranged near the extrusion die 20 and the first detector 41 and the second detector 42 .

In the extrusion die 20, the first lip 31 has a first detection surface 31a facing the first detector 41. As shown in FIG. The second lip 32 has a second detection surface 32a facing the second detector 42 . The first detection surface 31a and the second detection surface 32a are planes that form an angle with respect to the molten resin ejection direction (Z direction), and face the opposite direction (−Z direction) to the molten resin ejection direction. there is

As a result, the first detector 41 can detect the displacement of the first lip 31 and can be arranged so as to extend in the opposite direction (-Z direction) to the ejection direction of the molten resin. The second detector 42 can detect the displacement of the second lip 32 and can be arranged so as to extend in the opposite direction (-Z direction) to the ejection direction of the molten resin. Therefore, the extrusion die 20 can suppress interference between other devices arranged near the extrusion die 20 and the first detector 41 and the second detector 42 .

In the extrusion die 20, the first lip 31 has a first detection surface 31a facing the first detector 41. As shown in FIG. The second lip 32 has a second detection surface 32a facing the second detector 42 . The first detection surface 31a and the second detection surface 32a may be planes parallel to the ejection direction (Z direction) of the molten resin.

Thereby, the first detector 41 can detect the displacement of the first lip 31 in the lateral direction (X direction) of the ejection port 35 . The second detector 42 can detect the displacement of the second lip 32 in the lateral direction (X direction) of the ejection port 35 . The extrusion molding die 20 of the present embodiment can facilitate calculation of the lip gap G.

The extrusion die 20 includes a first connecting member 25 , a second connecting member 26 , a first support member 28 and a second support member 29 . The first connecting member 25 is arranged at one end of the first die body 21 in the longitudinal direction (Y direction) of the discharge port 35 and connects the first die body 21 and the second die body 22 . The second connecting member 26 is arranged at the other end of the first die body 21 in the longitudinal direction (Y direction) of the discharge port 35 and connects the first die body 21 and the second die body 22 . The first support member 28 is arranged on the side opposite to the second die body 22 with respect to the first die body 21 and is supported by the first connecting member 25 and the second connecting member 26 . The second support member 29 is arranged on the side opposite to the first die body 21 with respect to the second die body 22 and is supported by the first connecting member 25 and the second connecting member 26 . The first detector 41 is supported by the first support member 28 . The second detector 42 is supported by the second support member 29 .

As a result, the position of the first detector 41 is less susceptible to deformation of the first lip 31 than when the first detector 41 is fixed to the first die body 21 or the like. Therefore, the accuracy of displacement of the first lip 31 detected by the first detector 41 is improved. In addition, the position of the second detector 42 is less susceptible to deformation of the second lip 32 than when the second detector 42 is fixed to the second die body 22 or the like. Therefore, the accuracy of displacement of the second lip 32 detected by the second detector 42 is improved. Therefore, the extrusion molding die 20 can further improve the calculation accuracy of the lip gap G.

The method for measuring the lip gap of the present embodiment is a method for measuring the lip gap of the extrusion molding die 20 described above, and includes an initial measurement step S13 and a lip gap calculation step S17. In the initial measurement step S13, the initial lip gap, which is the width in the lateral direction (X direction) of the ejection port 35 in the initial state where the molten resin is not being ejected from the ejection port 35, is measured. In the lip gap calculation step S17, the lip gap G is calculated based on the initial lip gap, the displacement of the first lip 31 detected by the first detector 41, and the displacement of the second lip 32 detected by the second detector 42. Calculate

By calculating the lip gap G based on both the displacement of the first lip 31 and the displacement of the second lip 32, the lip gap measuring method can improve the calculation accuracy of the lip gap G. As a result, the thickness accuracy of the sheet can be improved according to the lip gap measurement method. According to the lip gap measuring method, the time required for adjusting the thickness of the sheet can be shortened.

The lip gap measuring method of the present embodiment includes a constant calculation step S15. In the constant calculation step S15, the displacement of the first lip 31 in the lateral direction (X direction) of the ejection port 35 and the first lip 31, and the relationship between the displacement of the second lip 32 in the lateral direction (X direction) of the discharge port 35 and the displacement of the second lip 32 detected by the second detector 42. A second constant representing is calculated. In the lip gap calculation step S17, the initial lip gap, the displacement of the first lip 31 detected by the first detector 41, the first constant, the displacement of the second lip 32 detected by the second detector 42, and the 2 constants to calculate the lip gap G.

As a result, even if the displacement detected by the first detector 41 and the second detector 42 is not displacement in the lateral direction (X direction) of the ejection port 35, the lip gap G can be calculated with high accuracy. Moreover, the directions of the first detection surface 31a as the detection target of the first detector 41 and the second detection surface 32a as the detection target of the second detector 42 are not limited. Therefore, the arrangement of the first detector 41 and the second detector 42 is easy.

11 Extruder 13 Cooling roll 15 Heating device 17 Thickness measuring device 20 Extrusion molding die 21 First die body 22 Second die body 23 Flow path 23a Introduction flow path 23b Manifold 23c Discharge flow path 25 First connection member 26 Second connection Member 28 First support member 29 Second support member 31 First lip 31a First detection surface 31b First auxiliary detection surface 32 Second lip 32a Second detection surface 32b Second auxiliary detection surface 35 Discharge port 41 First detector 42 Second detector 43 Adjusting device 51 First displacement measuring device 52 Second displacement measuring device 90 Control device 91 Input unit 93 Storage unit 95 Calculation unit 97 Control unit 100 Extrusion device G Lip gaps L1, L2 Straight line S11 Heating process S13 Initial stage measurement step S15 constant calculation step S17 lip gap calculation step θ1 angle θ2 angle

Claims (7)

a first die body;
a second die body facing the first die body across the flow path of the molten resin;
a first lip disposed at an end of the first die body;
a second lip disposed at the end of the second die body and facing the first lip across the molten resin discharge port;
a plurality of adjusting devices provided on the second die body to change a lip gap, which is a width of the ejection port in the lateral direction, and arranged along the longitudinal direction of the ejection port ;
a plurality of first detectors that detect the displacement of the first lip and are arranged along the longitudinal direction of the outlet ;
a plurality of second detectors that detect the displacement of the second lip and are arranged along the longitudinal direction of the outlet ;
with
the position of the first detector in the longitudinal direction of the ejection port corresponds to the position of the ejection port of the adjustment device in the longitudinal direction in a one-to-one correspondence,
The position of the outlet of the second detector in the longitudinal direction corresponds one-to-one with the position of the outlet of the adjustment device in the longitudinal direction.
Extrusion die. The first detector and the second detector are arranged in a direction opposite to the ejection direction of the molten resin with respect to the ejection port.
An extrusion die according to claim 1 . the first lip comprises a first detection surface facing the first detector;
the second lip comprises a second detection surface facing the second detector;
The first detection surface and the second detection surface are planes forming an angle with respect to the direction of ejection of the molten resin, and are oriented in a direction opposite to the direction of ejection of the molten resin.
An extrusion die according to claim 1 or 2 . the first lip comprises a first detection surface facing the first detector;
the second lip comprises a second detection surface facing the second detector;
The first detection surface and the second detection surface are planes parallel to the ejection direction of the molten resin.
An extrusion die according to claim 1 or 2 . a first connecting member disposed at one end of the first die body in the longitudinal direction of the discharge port and connecting the first die body and the second die body;
a second connecting member disposed at the other end of the first die body in the longitudinal direction of the discharge port and connecting the first die body and the second die body;
a first support member disposed on the side opposite to the second die body with respect to the first die body and supported by the first connection member and the second connection member;
a second support member disposed on the side opposite to the first die body with respect to the second die body and supported by the first connection member and the second connection member;
with
The first detector is supported by the first support member,
The second detector is supported by the second support member
An extrusion die according to any one of claims 1-4 . A method for measuring the lip gap of an extrusion die, comprising:
The extrusion die is
a first die body;
a second die body facing the first die body across the flow path of the molten resin;
a first lip disposed at an end of the first die body;
a second lip disposed at the end of the second die body and facing the first lip across the molten resin discharge port;
a plurality of adjusting devices provided on the second die body to change a lip gap, which is a width of the ejection port in the lateral direction, and arranged along the longitudinal direction of the ejection port ;
a plurality of first detectors that detect the displacement of the first lip and are arranged along the longitudinal direction of the outlet ;
a plurality of second detectors that detect the displacement of the second lip and are arranged along the longitudinal direction of the outlet ;
with
the position of the first detector in the longitudinal direction of the ejection port corresponds to the position of the ejection port of the adjustment device in the longitudinal direction in a one-to-one correspondence,
The position of the second detector in the longitudinal direction of the outlet corresponds to the position of the outlet of the adjustment device in the longitudinal direction in a one-to-one correspondence,
an initial measurement step of measuring an initial lip gap, which is the width of the ejection port in the lateral direction in an initial state in which the molten resin is not ejected from the ejection port;
a lip gap calculating step of calculating the lip gap based on the initial lip gap, the displacement of the first lip detected by the first detector, and the displacement of the second lip detected by the second detector; and,
A method of measuring a lip gap comprising: A first graph representing the relationship between the displacement of the first lip in the lateral direction of the ejection port and the displacement of the first lip detected by the first detector in a state in which the molten resin is ejected from the ejection port. a constant calculating step of calculating a constant and a second constant representing the relationship between the displacement of the second lip in the lateral direction of the ejection port and the displacement of the second lip detected by the second detector;
The initial lip gap, the displacement of the first lip detected by the first detector, the first constant, the displacement of the second lip detected by the second detector, and the second constant the lip gap calculating step of calculating the lip gap based on
The method of measuring a lip gap according to claim 6 , comprising:

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