Extrusion film forming apparatus

Abstract

To provide a relatively inexpensive extrusion film forming apparatus capable of safely cutting a molding material in a molten state or the like extruded from a die.SOLUTION: The extrusion film forming apparatus includes the die 18 that extrudes the molding material from the slit-shaped extrusion port 54, the die lip drive mechanism that changes the slit width D of the extrusion port 54, and the control device that controls the die lip drive mechanism, and the control device controls the die lip drive mechanism during the extrusion of the molding material and temporarily narrows the slit width D of the extrusion port 54 in order to cut the extruded molding material.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an extrusion deposition apparatus. [Background technology]

[0002] Conventionally, a film forming device has been known that extrudes a molten or softened (hereinafter, these are also collectively referred to as "molten, etc.") forming material from a long, narrow extrusion opening of a die to form a film-like molded product (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-111953 Summary of the Invention [Problem to be solved by the invention]

[0004] In an extrusion film-forming apparatus, the molten molding material extruded from the die needs to be cut at various times, for example, to prepare for the start of film formation.

[0005] Conventionally, an operator approaches the molten molding material extruded from the die and cuts it with a spatula, etc. However, this method is undesirable from a safety standpoint because the operator approaches the molten molding material at high temperatures.

[0006] Patent Document 1 proposes a method of cutting molten molding material extruded from a die using a cutter device. This method eliminates the need for an operator to approach the molten molding material. However, this method requires the operator to periodically clean the area around the die's extrusion outlet and the cutter, placing a burden on the operator. Furthermore, this method requires a cutter device, which increases costs. Furthermore, this method requires installation space for the cutter device, which increases the size of the extrusion film-forming apparatus. These issues can become serious when the die is long in the width direction.

[0007] The present disclosure has been made in consideration of these circumstances, and one exemplary purpose of one aspect thereof is to provide a relatively low-cost extrusion film forming device that can safely cut molding material in a molten state or the like that has been extruded from a die. [Means for solving the problem]

[0008] In order to solve the above problems, an extrusion film forming apparatus according to one aspect of the present disclosure includes a die for extruding a molding material through a slit-shaped extrusion opening, a die lip drive mechanism for changing the slit width of the extrusion opening, and a control device for controlling the die lip drive mechanism. The control device controls the die lip drive mechanism during extrusion of the molding material to temporarily narrow the slit width of the extrusion opening to cut the extruded molding material.

[0009] Any combination of the above components, or mutual substitution of the components or expressions of the present disclosure between methods, devices, systems, etc., are also valid aspects of the present disclosure. [Effects of the Invention]

[0010] According to an aspect of the present disclosure, it is possible to provide a low-cost extrusion film-forming device that can safely cut molding material in a molten state or the like that has been extruded from a die. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a schematic configuration diagram of a film forming system including an extrusion film forming device according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 2 is a perspective view showing the die and its periphery in FIG. 1. [Figure 4] 4(a) and (b) are diagrams illustrating a method for cutting the film. [Figure 5] FIG. 10 is a cross-sectional view showing a die and its periphery in an extrusion film-forming apparatus according to a modified example. [Figure 6] FIG. 10 is a cross-sectional view showing a die and its periphery in an extrusion film-forming apparatus according to a modified example. [Figure 7] FIG. 10 is a diagram showing a die and its periphery in an extrusion film-forming apparatus according to another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure will be described below based on preferred embodiments with reference to the drawings. The embodiments are illustrative and do not limit the disclosure, and all features and combinations described in the embodiments are not necessarily essential to the disclosure. In the embodiments, identical or equivalent components and members are designated by the same reference numerals, and redundant descriptions will be omitted as appropriate.

[0013] In the following, XYZ Cartesian coordinates may be used, where the X axis extends across the width of the sheet film being formed, the Z axis extends vertically, and the Y axis extends in a direction perpendicular to the X and Z axes.

[0014] 1 and 2, the film forming system 1 forms a thin film, in this embodiment a sheet-like film. The film forming system 1 includes an extrusion film forming device 2, a take-up molding device 4, and a film conveying device and a winding machine (not shown).

[0015] The extrusion film-forming apparatus 2 melts the molding material and extrudes it into a sheet form through the die 18. As a modified example, the extrusion film-forming apparatus 2 may soften the molding material and extrude it into a sheet form through the die 18. Hereinafter, the molding material extruded through the die 18 will also be referred to as a film.

[0016] The drawing-molding device 4 draws the film extruded into a sheet shape and performs predetermined processing on the film. In this embodiment, the drawing-molding device 4 cools the film.

[0017] As a modified example, a base sheet may be fed into the drawing-molding device 4. The drawing-molding device 4 may press-bond this base sheet and a sheet-like film extruded from the die 18 to form a laminated film.

[0018] The film transport device transports the film to a winder, which winds the film into a roll.

[0019] The extrusion film forming apparatus 2 comprises a material discharge section 12, a conveying section 14 connected downstream of the material discharge section 12, a die 18 connected downstream of the conveying section 14, a plurality of die lip driving mechanisms 56 for changing the width in the Y-axis direction of the slit-shaped extrusion opening 54 of the die 18 (hereinafter referred to as the slit width), a thickness meter 28 for measuring the thickness of the film, and a control device 30.

[0020] The material delivery section 12 melts the solid molding material and delivers it downstream, i.e., to the conveying section 14. The material delivery section 12 is a so-called extruder, and includes a hopper 20, a cylinder 22, a screw 24, and a crosshead section 26.

[0021] The hopper 20 has an opening facing upward, and the granular molding material is poured into the hopper 20. The inside of the hopper 20 is connected to a cylinder 22, and the molding material poured into the hopper 20 enters the cylinder 22.

[0022] The cylinder 22 has a heating means such as a heater, etc. The molding material supplied to the cylinder 22 is heated by the heater and melted.

[0023] The screw 24 is housed within the cylinder 22. The screw 24 rotates to feed the molding material to the crosshead portion 26. Increasing the rotation speed of the screw 24 increases the amount of molding material fed out.

[0024] The crosshead unit 26 changes the conveying direction of the molding material from the Y-axis direction to the Z-axis direction, and guides the molding material to the conveying unit 14. The crosshead unit 26 may be configured using known or future available technology.

[0025] The conveying section 14 conveys the molten molding material to the die 18. The conveying section 14 includes a flow path 16 extending in the Z-axis direction. The flow path 16 has, although not particularly limited to, the same cross-sectional shape and cross-sectional area over its entire length.

[0026] In this embodiment, the die 18 is a T-die and has a rectangular extrusion opening 54 extending in the X-axis direction. The extrusion opening 54 faces vertically downward. Therefore, the die 18 extrudes the conveyed molten molding material in a sheet shape from the extrusion opening 54 vertically downward, i.e., in the direction of gravity.

[0027] The flow path 40, which is the internal space of the die 18, has an upstream section 42, a midstream section 44, and a downstream section 46. The upstream section 42 is connected to the flow path 16 of the conveying section 14. The upper end of the upstream section 42 has the same cross-sectional shape and cross-sectional area as the flow path 16 of the conveying section 14. The midstream section 44 is located between and connected to the upstream section 42 and the downstream section 46. The midstream section 44 increases in the X-axis direction toward the downstream side. The downstream section 46 has a tapered section that decreases in the Y-axis direction toward the downstream side. The lower end of the downstream section 46 of the flow path 40 forms the extrusion outlet 54. The molding material flows in from the upstream section 42, expands in the X-axis direction in the midstream section 44, and is thinned in the Y-axis direction in the downstream section 46 before being extruded into a sheet from the extrusion outlet 54.

[0028] See Figure 3. The multiple die lip drive mechanisms 56 are arranged, for example, at equal intervals in the X-axis direction. Each of the multiple die lip drive mechanisms 56 changes the slit width of the extrusion outlet 54 at each position in the X-axis direction. More specifically, each of the multiple die lip drive mechanisms 56 widens the slit width of the extrusion outlet 54 by pulling the die 18 in the Y-axis direction at each position in the X-axis direction, and narrows the slit width of the extrusion outlet 54 by pushing the die 18 in the Y-axis direction.

[0029] 1, the thickness meter 28 measures the thickness of the film at each position in the X-axis direction, for example, at a predetermined cycle. The thickness meter 28 transmits the measured thickness to the control device 30.

[0030] The control device 30 controls the die lip drive mechanisms 56. More specifically, the control device 30 performs calculations based on the measurement values ​​of the thickness gauge 28 and operates each die lip drive mechanism 56 so as to achieve a specified film thickness.

[0031] The above is the basic configuration of the film forming system 1. Next, the operation thereof will be described.

[0032] The extrusion film-forming apparatus 2 melts the granular molding material supplied from the hopper 20 using the cylinder 22. The molten molding material is sent downstream by the rotation of the screw 24. The crosshead unit 26 sends the molten molding material to the conveying unit 14. The molding material passes through the conveying unit 14 and is sent to the die 18, where it is extruded into a sheet from the extrusion outlet 54. The control device 30 controls each die lip drive mechanism 56 according to an instruction value for the film thickness, at an appropriate timing before and / or after the start of molding. The control device 30 also controls each die lip drive mechanism 56 during molding to correct any deviations in the film thickness.

[0033] Incidentally, in the extrusion film forming apparatus 2, it is necessary to cut the film extruded from the extrusion port 54 of the die 18 at various timings. For example, in the preparation for starting the molding, it is necessary to cut the film at a position higher than, for example, the two rollers 6 and 8 in order to pass the film between the two rollers 6 and 8 of the take-up molding apparatus 4. Also, for example, the film may be cut to switch the take-up core for winding the film in the winder.

[0034] Therefore, in the present embodiment, while the molding material is being extruded from the extrusion port 54, the control device 30 controls the die lip drive mechanism 56, and temporarily narrows the slit width of the extrusion port 54 for cutting the film F.

[0035] This will be described in detail with reference to FIGS. 4(a) and (b). FIG. 4(a) is a view of the die 18 and its surroundings as seen in the X-axis direction, and FIG. 4(b) is a view of the die 18 and its surroundings as seen in the Y-axis direction. The control device 30 narrows the slit width D of the extrusion port 54 in the Y-axis direction from the first width d1 to the second width d2 (<d1), and after a lapse of a predetermined time (for example, 1 second), widens it from the second width d2 to the third width d3 (>d2).

[0036] As a result, the thickness of the extruded film F is also changed in the order of d1 → d2 → d3 as the slit width D is changed, and a notch portion (dent) Fn, which is a portion where the thickness is locally reduced and extends in the X-axis direction, is formed in the film F. Since the notch portion Fn is thin, that is, has low rigidity, the film F is cut at the notch portion Fn by the weight of the hanging portion below the notch portion Fn.

[0037] For example, the control device 30 controls a moving mechanism (not shown) to retract the take-up molding apparatus 4 to a position not facing the extrusion port 54 of the die 18 in the vertical direction, temporarily narrow the slit width D of the extrusion port 54 during film formation to form the notch portion Fn and cut the film, and then return the take-up molding apparatus 4 to a position facing the extrusion port 54 of the die 18 in the vertical direction to receive the film hanging from the extrusion port 54 between the two rollers 6 and 8.

[0038] Preferably, in order to realize the local notch portion Fn, the higher the responsiveness of the actuator of the die lip drive mechanism 56, the better. Therefore, the actuator of the die lip drive mechanism 56 is preferably a fluid pressure actuator, for example, a pneumatic actuator.

[0039] Preferably, the control device 30 simultaneously deforms the slit width D of the extrusion outlet 54 over the entire range in the X-axis direction. In this case, a notch portion Fn extending straight in the X-axis direction is formed, and therefore the film F is cut straight in the X-axis direction.

[0040] However, if the film F is cut, the timing for changing the slit width D of the extrusion outlet 54 may be different in a partial range in the X-axis direction. Also, if the film F is cut, the slit width D of the extrusion outlet 54 may not be changed in at least a partial range in the X-axis direction.

[0041] The first width d1 and the third width d3 may be the same width or may be different widths.

[0042] The third width d3 may be the same width as the thickness of the product. In this case, the product can be formed with the slit width D unchanged or by only slightly changing the slit width D.

[0043] The first width d1 may be greater than the third width d3. For example, the first width d1 may be greater than the thickness of the molded product. In this case, the hanging portion below the notch Fn is relatively heavy and therefore easily cut at the notch Fn.

[0044] The second width d2 may be 0. That is, the extrusion opening 54 may be completely closed. However, if the extrusion opening 54 of the die 18 is completely closed, metal parts may come into contact with each other, which may cause scratches or wear on the inside of the die 18 (i.e., the flow path surface). Furthermore, if the extrusion opening 54 of the die 18 is completely closed, the film F is cut in the immediate vicinity of the extrusion opening 54, which may cause the film F to adhere to the vicinity of the extrusion opening 54. Therefore, it is preferable that the second width d2 is greater than 0. That is, it is preferable that the extrusion opening 54 is not completely closed.

[0045] The position at which the film F is cut can vary depending on the size of the second width d2. If the second width d2 is 0, the film F is cut very close to the extrusion outlet 54, and as the second width d2 increases, the film F is cut at a position farther from the extrusion outlet 54. If the second width d2 is small and the film F is cut close to the extrusion outlet 54, the remaining film F may adhere to the vicinity of the extrusion outlet 54. If the second width d2 is large and the notch portion Fn is formed thick, the rigidity of the notch portion Fn may be so high that the film F may not be cut. Therefore, widths d1 to d3 are determined taking these factors into consideration, for example, by experimentation or simulation.

[0046] For example, the widths d1 to d3 can have the following three combination patterns: By adopting an appropriate pattern, it is possible to adapt to various molding materials with different materials and properties.

[0047] (First pattern) First width d1: The same width as the production molding setting Second width d2:d2 <d1およびd2<d3 Third width d3: The same width as the production molding setting In this case, after cutting, the slit width D of the extrusion port 54 can be left as it is or changed only slightly to start production molding.

[0048] (Second pattern) First width d1: Width larger than the setting during production molding Second width d2:d2 <d1およびd2<d3 Third width d3: The same width as the production molding setting In this case, the hanging portion below the notch Fn becomes heavier and is therefore more likely to be cut at the notch Fn. After cutting, production molding can begin with the slit width D of the extrusion outlet 54 remaining the same or with only a slight change to the slit width D.

[0049] (Third pattern) First width d1: Width larger than the setting during production molding Second width d2:d2 <d1およびd2<d3 Third width d3: Width larger than the setting during production molding In this case, the hanging portion below the notch portion Fn becomes heavier and is therefore more likely to be cut at the notch portion Fn.

[0050] According to the present embodiment described above, the molten molding material can be cut safely, without the operator having to approach the molten molding material. Furthermore, since a cutter device is not required to cut the molten molding material, costs can be reduced. In other words, according to the present embodiment, a relatively low-cost extrusion deposition apparatus 2 that can safely cut the molten molding material can be provided.

[0051] The present disclosure has been described above based on the embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of the respective components and treatment processes, and that such modifications are also within the scope of the present invention.

[0052] (Variation 1) In the embodiment, the film forming system 1 has been described as forming a sheet-shaped film, but this is not limiting. For example, the film forming system 1 may form a tubular film. In this case, the die 18 of the extrusion film forming device 2 of the film forming system 1 may be a round die, i.e., a die having a ring-shaped extrusion opening. In this case, the slit width of the extrusion opening is the radial width of the extrusion opening.

[0053] (Variation 2) Please refer to Figures 5 and 6. Figures 5 and 6 correspond to Figure 2. In this modified example, the extrusion deposition apparatus 2 is equipped with volume change units 202R and 202L that change the volume of the flow path 40 of the die 18. The volume change unit 202R is located at one end of the die 18 in the X-axis direction, and the volume change unit 202L is located at the other end of the die 18 in the X-axis direction. The volume change units 202R and 202L are driven simultaneously by the control device 30 and have the same configuration, so they will be collectively referred to as "volume change unit 202" below for detailed description.

[0054] The volume varying unit 202 includes a chamber 204 , a piston 206 , and an actuator 208 .

[0055] The chamber 204 is connected to the flow path 40 (midstream portion 44 in the illustrated example) and is airtight from the outside by a partition wall 210. A piston 206 is disposed within the chamber 204. The chamber 204 extends parallel to the X-axis.

[0056] The piston 206 includes a head 212 and a rod 214. The head 212 is fixed to one end of the rod 214. The head 212 is in airtight contact with the inner circumferential surface of the chamber 204. The other end of the rod 214 extends through the partition wall 210 into the actuator 208. A seal is formed between the rod 214 and the partition wall 210. The actuator 208 is controlled by the control device 30. When the pressure in the actuator 208 decreases, the piston 206 is pulled in a direction away from the flow path 40. When the pressure in the actuator 208 increases, the piston 206 is pushed toward the flow path 40. Hereinafter, a state in which the end face of the head 212 is flush with the inner wall surface that defines the end face in the X-axis direction of the downstream portion 46 of the flow path 40, i.e., the state shown in FIG. 5, is considered to be the leading end position of the piston 206. Also, the state in which the head 212 is retracted into the chamber 204, that is, the state shown in FIG. 6, is considered to be the state in which the piston 206 is in the retracted position.

[0057] When piston 206 is in the retracted position, flow path 40 and the internal space of chamber 204 can be considered to form one continuous space. That is, the internal space of chamber 204 can also be considered to constitute flow path 40. Therefore, when piston 206 is in the retracted position, the volume of flow path 40 is larger than when piston 206 is in the tip position. That is, when actuator 208 drives piston 206 between the tip position and the retracted position, the volume of flow path 40 changes.

[0058] The control device 30 increases the volume of the flow path 40 simultaneously with or after the formation of the notch portion Fn. In other words, the control device 30 increases the volume of the flow path 40 simultaneously with or after the slit width of the extrusion outlet 54 is temporarily narrowed to cut the film.

[0059] The notch portion Fn is pulled downward by the weight of the hanging portion on the lower side. Meanwhile, while the volume of the flow path 40 is being increased, the speed at which the molding material is extruded from the extrusion port 54 decreases, so the notch portion Fn is also pulled upward. In other words, the notch portion Fn is pulled vertically, so it is cut more reliably.

[0060] As a further modification, the volume changing unit 202 may be arranged and configured to change the volume of the flow path 16 of the conveying unit 14. In other words, the volume changing unit 202 may be arranged and configured to change the volume of the flow path leading to the extrusion port 54.

[0061] However, if the volume change unit 202 is arranged and changed so as to change the volume of the flow path 40 closer to the extrusion port 54, the delay between when the volume change unit 202 is activated and when the extrusion amount of the molding material changes can be reduced. Also, the flow path 40 of the die 18 closer to the extrusion port 54 has a lower pressure than the flow path 16 of the conveying unit 14. Therefore, by arranging the volume change unit 202 closer to the extrusion port 54, the energy required to retract the piston 206 into the chamber 204 can be reduced. This allows the actuator 208 to be made smaller.

[0062] (Variation 3) Please refer to Fig. 7. Fig. 7 is a view of the die 18 and its periphery of the extrusion film forming apparatus 2 according to another modified example, viewed in the Y-axis direction. Fig. 7 corresponds to Fig. 4(b).

[0063] In this modified example, the extrusion film forming apparatus 2 further includes a cutting assist unit 60. The control device 30 further controls the cutting assist unit 60. The control device 30 operates the cutting assist unit 60 in conjunction with the formation of the notch portion Fn (i.e., the operation of each die lip drive mechanism 56), and applies a force to the hanging portion below the notch portion Fn, thereby applying stress to the end portion Fne of the notch portion Fn in the X-axis direction, making it easier for the film F to be cut at the notch portion Fn.

[0064] For example, the cutting assist unit 60 includes a pressing member 62 and a movement mechanism 64 that moves the pressing member 62. The pressing member 62 may be a rod-shaped member that extends in the Y-axis direction.

[0065] Control device 30 may control movement mechanism 64 to move pressing member 62 in the X-axis direction as shown, and press the portion of the film that hangs down below notch portion Fn in the X-axis direction (i.e., the width direction of the film) with pressing member 62. This applies stress to end portion Fne of notch portion Fn.

[0066] Control device 30 may control movement mechanism 64 to move pressing member 62 in the Y-axis direction, and press the portion of the film that hangs down below notch portion Fn in the Y-axis direction (i.e., the thickness direction of the film) with pressing member 62. For example, a portion near end Fne of notch portion Fn may be pressed in the Y-axis direction. This applies stress to end Fne of notch portion Fn.

[0067] When stress is applied to the end Fne of the notch Fn, the notch Fn begins to break from the end Fne, and it is expected that the entire notch Fn will be reliably cut off.

[0068] Any combination of the above-described embodiments and modifications is also useful as an embodiment of the present invention. A new embodiment resulting from the combination has the combined effects of the combined embodiments and modifications. [Explanation of symbols]

[0069] 2 Extrusion film forming device, 14 Conveying section, 18 Die, 30 Control device, 54 Extrusion outlet, 56 Die lip driving mechanism, 60 Cutting support section, 202 Volume changing section.

Claims

1. a die that extrudes a molding material from a slit-shaped extrusion opening; a die lip drive mechanism for changing the slit width of the extrusion outlet; a control device that controls the die lip drive mechanism; Equipped with The control device controls the die lip drive mechanism during extrusion of the molding material to temporarily narrow the slit width of the extrusion outlet in order to cut the extruded molding material.

2. The extrusion film forming apparatus according to claim 1 , wherein the control device widens the temporarily narrowed slit width of the extrusion outlet to a width set for production molding.

3. The extrusion film forming apparatus according to claim 1 , wherein the control device temporarily narrows the slit width of the extrusion outlet before widening the slit width to a width greater than the width set for production molding.

4. a volume change unit that changes the volume of the flow path leading to the extrusion port, The extrusion deposition apparatus according to claim 1 , wherein the control device controls the volume changer to increase the volume of the flow path simultaneously with or after narrowing the slit width of the extrusion port.

5. The extrusion film forming apparatus according to claim 1 , further comprising a cutting support unit that applies force to a portion of the film that hangs down below a portion that has been locally thinned by narrowing the slit width of the extrusion outlet.

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