JP2023117083A - Resin molding device and resin molding method - Google Patents

Abstract

To provide a resin molding device capable of preventing misalignment of a thermoplastic resin sheet set on an upper surface of a lower mold, improving a shape accuracy by press molding, and suppressing occurrence of distortion caused by air bubbles in the thermoplastic resin sheet.SOLUTION: There is provided a resin molding device for molding a heated thermoplastic resin sheet, comprises: a lower mold; an upper mold that presses the thermoplastic resin sheet between itself and the lower mold; and a cloth holding mechanism that is provided around the lower mold to hold a cloth stretched between the lower mold and the upper mold. The cloth is spaced apart from the lower mold and the upper mold in between the lower mold and the upper mold, and is stretched perpendicular to a pressing direction of the lower mold and the upper mold. The lower mold and the upper mold are provided so as to press the thermoplastic resin sheet in a state of placing apart from the lower mold and the upper mold on the cloth.SELECTED DRAWING: Figure 1

Description

The present invention relates to a resin molding apparatus and a resin molding method.

Various techniques related to a resin molding apparatus for molding a heated thermoplastic resin sheet have been proposed. For example, in the method for conveying a heat-softened resin sheet described in the following patent document, a thermoplastic resin sheet is placed on a rotating belt and heated together with the rotating belt to soften the thermoplastic resin sheet. Then, the rotary belt is positioned right above the lower die, and the clamp is arranged so as to face one end of the rotary belt.

Subsequently, the belt member of the rotary belt is rotated in the delivery direction, one end of the thermoplastic resin sheet is held by a clamp, and the rotary belt is moved away from the lower die while continuing to rotate in the delivery direction. After that, at the same time when the other end of the thermoplastic resin sheet is separated from the rotating belt, the holding of the one end of the thermoplastic resin sheet by the clamp is released, and the thermoplastic resin sheet is placed on the upper surface of the lower die. Then, the clamp is separated from the lower mold, the upper mold is lowered against the lower mold, and the thermoplastic resin sheet is formed into a predetermined shape.

JP-A-2000-326328

However, when the holding of both ends of the thermoplastic resin sheet is released above the lower mold and the thermoplastic resin sheet is dropped and placed on the upper surface of the lower mold, air There is a risk that resistance will be received, or that the release timing of the clamp will be shifted. As a result, the thermoplastic resin sheet may be placed on the upper surface of the lower die in a positional deviation from the reference position to be set, and the shape accuracy by press molding may be degraded. Also, when the thermoplastic resin sheet is set on the upper surface of the lower mold, air bubbles are trapped between the thermoplastic resin sheet and the upper surface of the lower mold. There is a possibility that the resin sheet may be distorted.

Accordingly, the present invention has been devised in view of the above points, and is capable of preventing misalignment of a thermoplastic resin sheet set on the upper surface of a lower mold and improving the shape accuracy of press molding. Another object of the present invention is to provide a resin molding apparatus and a resin molding method capable of suppressing the generation of distortion due to air bubbles in a thermoplastic resin sheet.

In order to solve the above problems, a first invention of the present invention is a resin molding apparatus for molding a heated thermoplastic resin sheet, wherein the thermoplastic resin sheet is molded between a lower mold and the lower mold. An upper mold for pressing, and a cloth holding mechanism provided around the lower mold and holding a cloth stretched between the lower mold and the upper mold, wherein the cloth is held between the lower mold and the upper mold. Between the upper mold and the lower mold and the upper mold, it is spaced apart from the lower mold and the upper mold and is stretched perpendicular to the pressing direction of the lower mold and the upper mold, and the lower mold and the upper mold are: In the resin molding apparatus, the thermoplastic resin sheet placed on the cloth at a distance from the lower mold and the upper mold can be pressed.

Next, according to a second aspect of the present invention, in the resin molding apparatus according to the first aspect, the cloth holding mechanism is arranged such that the center of the cloth stretched between the lower mold and the upper mold is: In the resin molding apparatus, the cloth is held so as to face a reference position on the upper surface of the lower mold on which the center of the thermoplastic resin sheet is placed.

Next, according to a third invention of the present invention, in the resin molding apparatus according to the first invention or the second invention, the cloth holding mechanism is provided integrally with the lower mold, and In the resin molding apparatus, the cloth stretched between the upper mold and the cloth is fixed in height from the upper surface of the lower mold.

Next, according to a fourth invention of the present invention, in the resin molding apparatus according to the first invention or the second invention, the cloth holding mechanism is provided separately from the lower mold, The resin molding apparatus is set so that the vertical position of the cloth stretched between the upper mold and the upper mold does not change.

Next, according to a fifth aspect of the present invention, in the resin molding apparatus according to any one of the first to fourth aspects, the cloth holding mechanism holds the cloth by sandwiching it from above and below. The resin molding apparatus has a frame body portion, and the frame body portion has a lower frame on which the cloth is placed and an upper frame attached to the lower frame with the cloth sandwiched therebetween.

Next, according to a sixth aspect of the present invention, in the resin molding apparatus according to any one of the first to fifth aspects, the cloth has a surface on which the thermoplastic resin sheet is placed. It is a resin molding device that is raised.

Next, a seventh invention of the present invention is a resin molding method for molding the thermoplastic resin sheet using the resin molding apparatus according to the first invention, wherein the heated thermoplastic resin sheet is a sheet placing step of placing the sheet on the central portion of the cloth; and a molding step of pressing with the upper mold.

According to the first and seventh inventions, the heated thermoplastic resin sheet is once placed on the cloth stretched between the lower mold and the upper mold, so that the weight of the thermoplastic resin sheet causes the cloth to bend, and the center (center of gravity) of the thermoplastic resin sheet moves to the center of the cloth. By positioning the thermoplastic resin sheet to be set on the upper surface of the lower mold at the center of the cloth in this way, misalignment can be corrected, and shape accuracy by press molding can be improved.

Further, the lower mold and the upper mold are provided so as to be able to press the thermoplastic resin sheet placed on the cloth while being separated from the lower mold and the upper mold. As a result, the thermoplastic resin sheet placed on the cloth is separated from the lower mold, so that heat escapes from the thermoplastic resin sheet to the lower mold until the thermoplastic resin sheet is pressed. temperature can be suppressed. Therefore, deterioration of the moldability of the thermoplastic resin sheet can be suppressed.

Also, when the thermoplastic resin sheet placed on the cloth is pressed by the lower mold and the upper mold, even if air bubbles enter between the upper surface of the lower mold and the thermoplastic resin sheet, Air bubbles are discharged from the gap between the cloth and the thermoplastic resin sheet. Therefore, when the thermoplastic resin sheet placed on the cloth is pressed by the lower mold and the upper mold, it is possible to suppress the occurrence of distortion due to air bubbles in the thermoplastic resin sheet.

According to the second invention, the center of the cloth stretched between the lower mold and the upper mold faces the reference position of the upper surface of the lower mold on which the center of the thermoplastic resin sheet is placed. When the cloth bends due to the weight of the plastic sheet and the center (center of gravity) of the thermoplastic resin sheet moves to the center of the cloth, the center of the thermoplastic resin sheet should be aligned with the center of the thermoplastic resin sheet on the upper surface of the lower die. It is arranged so as to face the reference position to be aligned. As a result, the center (center of gravity) of the thermoplastic resin sheet can be set at the reference position to be aligned with the center of the thermoplastic resin sheet on the upper surface of the lower mold and pressed, further improving the shape accuracy by press molding. can be planned.

According to the third invention, the cloth holding mechanism is provided integrally with the lower mold, and the height from the upper surface of the lower mold stretched between the lower mold and the upper mold is fixed. . As a result, there is no need to provide a drive mechanism for moving the cloth up and down, and the number of parts of the resin molding apparatus can be reduced to simplify the structure.

According to the fourth invention, the cloth holding mechanism is provided separately from the lower mold and is set so that the vertical position of the cloth stretched between the lower mold and the upper mold does not change. there is Thereby, the vertical height of the cloth can be adjusted independently, and the vertical height of the cloth can be easily adjusted.

According to the fifth invention, the cloth is sandwiched and held from above and below by the frame portion composed of the upper frame and the lower frame. As a result, when the thermoplastic resin sheet is placed on the cloth, the cloth bends due to the weight of the thermoplastic resin sheet itself, and the center of the thermoplastic resin sheet (center of gravity) moves toward the center of the cloth held by the frame portion. ) can be reliably moved.

According to the sixth aspect of the invention, since the surface of the cloth on which the thermoplastic resin sheet is placed is raised, when the cloth is pressed by the lower mold and the upper mold, the weave of the cloth is adjusted to the surface of the thermoplastic resin sheet. It is possible to suppress the sticking, and it is possible to improve the quality.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows an example of schematic structure of the resin molding apparatus which concerns on 1st Embodiment. FIG. 4 is an exploded perspective view showing a frame portion that holds the periphery of the cloth of the cloth holding mechanism; FIG. 4 is a cross-sectional view for explaining a state in which a cloth is held by a frame body; FIG. 4 is a perspective view illustrating a clamped state of a heated thermoplastic resin sheet; FIG. 4 is a diagram schematically illustrating a state in which a heated thermoplastic resin sheet is placed on a cloth and positioned; 1. It is a figure which illustrates typically an example of the procedure which presses the thermoplastic resin sheet heated by the resin molding apparatus shown in FIG. It is a perspective view which shows an example of schematic structure of the resin molding apparatus which concerns on 2nd Embodiment. 8 is a diagram illustrating an example of a procedure for pressing a heated thermoplastic resin sheet by the resin molding apparatus shown in FIG. 7; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment and a second embodiment embodying a resin molding apparatus and a resin molding method according to the present invention will be described in detail below with reference to the drawings. First, a schematic configuration of a resin molding apparatus 1 according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 shows an example of a schematic configuration of a resin molding apparatus 1 according to the first embodiment. The resin molding apparatus 1 is used, for example, when molding a resin rear window of a vehicle.

[First embodiment]
As shown in FIG. 1, a resin molding apparatus 1 is an apparatus for molding a heated thermoplastic resin sheet 3. As shown in FIG. Specifically, the resin molding apparatus 1 presses the heated thermoplastic resin sheet 3 with a mold to mold the thermoplastic resin sheet 3 into a desired shape corresponding to the shape of the mold. The thermoplastic resin sheet 3 is heated in advance by a heating device such as a heating furnace, for example, to a temperature at which the thermoplastic resin softens and can be molded by pressing. The thermoplastic resin sheet 3 is a sheet-shaped thermoplastic resin. Examples of thermoplastic resins include PA6, PA66, ABS, PP, PPS, and PC.

The resin molding apparatus 1 includes a lower mold 5 , an upper mold 6 and a cloth holding mechanism 7 . The lower die 5 is supported from below by, for example, a lower die support portion 11 having a rectangular shape in plan view. The upper mold 6 is supported from above by, for example, an upper mold supporting portion 12 having a rectangular shape in plan view. The lower mold 5 and the upper mold 6 are a pair of molds arranged to face each other. At least one of the lower mold 5 and the upper mold 6 moves in the press direction (the mold closing direction) to close the lower mold 5 and the upper mold 6 .

For example, the upper die 6 is arranged vertically above the lower die 5, and the "pressing direction" is the vertical direction. Here, the lower mold 5 and the upper mold 6 close due to the upper mold 6 moving downward in the vertical direction. The resin molding apparatus 1 includes actuators (not shown) that move the lower mold 5 and the upper mold 6 in the pressing direction.

The lower die 5 is one of a pair of dies for pressing the thermoplastic resin sheet 3 . The lower mold 5 has a lower mold base portion 5A and a lower mold convex portion 5B. The lower mold base 5A is formed in a rectangular plate shape in a plan view, for example. The lower mold convex portion 5B is a thick plate-like portion formed so as to protrude from the upper surface of the lower mold base portion 5A (that is, the surface on the upper mold 6 side). The lower mold convex portion 5B is disposed substantially in the center of the lower mold base portion 5A and formed in a rectangular shape in plan view that is slightly smaller than the lower mold base portion 5A. The upper surface of the lower mold protrusion 5B is formed so that the upper end edge of the side cross section in the direction orthogonal to the longitudinal direction protrudes upward in a curved shape with a predetermined curvature radius. The lower mold base portion 5A and the lower mold convex portion 5B are integrally formed as a single member.

The upper mold 6 is the other mold of a pair of molds for pressing the thermoplastic resin sheet 3 . The upper mold 6 presses the thermoplastic resin sheet 3 between itself and the lower mold 5 . The upper die 6 is formed in the shape of a thick plate that is rectangular in plan view, and the longitudinal direction thereof is arranged along the longitudinal direction of the lower die convex portion 5B. On the lower surface of the upper mold 6 (that is, the surface on the lower mold 5 side), the lower end edge of the side cross section in the direction orthogonal to the longitudinal direction is curved upward with a predetermined curvature radius. A recess 6A is formed.

When the lower mold 5 and the upper mold 6 are closed, the upper surface of the lower mold protrusion 5B and the lower surface of the upper mold recess 6A are arranged to face each other. At this time, a gap is formed between the upper surface of the lower mold protrusion 5B and the lower surface of the upper mold recess 6A for forming the thermoplastic resin sheet 3 into a curved shape having a predetermined radius of curvature.

The cloth holding mechanism 7 is provided around the lower mold 5 and the upper mold 6 and holds the peripheral edge of the cloth 9 stretched between the lower mold 5 and the upper mold 6 . For example, the cloth holding mechanism 7 includes a frame portion 15 that is substantially rectangular in plan view, and a first frame support portion 16A, a second frame support portion 16B, and a third frame support portion that support the four corners of the lower surface of the frame portion 15. 16C and a fourth frame support portion 16D. The first frame support portion 16A, the second frame support portion 16B, the third frame support portion 16C, and the fourth frame support portion 16D are positioned on the four corner sides of the lower mold support portion 11 relative to the lower mold 5. These columns are arranged so as not to change, and are provided so as to stand in the vertical direction.

In addition, the first frame support portion 16A, the second frame support portion 16B, the third frame support portion 16C, and the fourth frame support portion 16D are arranged so that the height from the lower die support portion 11 to the upper end surface is equal. are formed and attached to the four corners of the lower surface of the frame portion 15 . As a result, the frame body part 15 is separated from the lower mold 5 and the upper mold 6 between the lower mold 5 and the upper mold 6, and the pressing direction of the lower mold 5 and the upper mold 6 (the direction in which the mold is closed). placed perpendicular to the

2 and 3, the frame portion 15 has a lower frame 15A, an upper frame 15B, and cloth 9. As shown in FIGS. The lower frame 15A includes a frame portion 17 formed in a square frame having a rectangular shape in a plan view and opening in the vertical direction, and a predetermined length (for example, , about 4 cm to 8 cm), and has a rectangular frame-shaped cloth receiving portion 19 forming a rectangular opening 18 in a plan view in the central portion. Here, as shown in FIG. 1, the opening 18 is formed in a rectangular shape larger than the lower mold protrusion 5B and the upper mold 6. As shown in FIG. Further, the center of the opening 18 of the lower frame 15A is positioned at the reference position of the upper surface of the lower mold projection 5B to which the center (center of gravity) of the thermoplastic resin sheet 3 is to be aligned. They are supported by the first frame support portion 16A to the fourth frame support portion 16D so as to face each other in the center.

As shown in FIG. 3, the upper frame 15B is fitted inside the lower frame 15A with the cloth 9 interposed therebetween and fixed by bolting or the like to hold the stretched cloth 9 at its periphery. As shown in FIGS. 2 and 3, the upper frame 15B includes a frame portion 21 that can be inserted into the inner side of the lower frame 15A, and a predetermined length extending perpendicularly inward from the lower end portion of the frame portion 21 along the entire circumference. It has a rectangular frame-shaped cloth pressing portion 23 extending by a length (for example, about 4 cm to 8 cm) and forming a rectangular opening 22 in a plan view at the center.

Therefore, as shown in FIGS. 1 and 3, the opening 22 is formed in the same shape as the opening 18 and is formed in a rectangular shape larger than the lower mold projection 5B and the upper mold 6. As shown in FIG. In the upper frame 15B, similarly to the lower frame 15A, the center of the opening 22 is positioned at the reference position on the upper surface of the lower mold protrusion 5B to which the center (center of gravity) of the thermoplastic resin sheet 3 is to be aligned. They are arranged so as to face each other at the center of the upper surface of the mold projection 5B.

As shown in FIGS. 2 and 3, the cloth 9 is formed in a rectangular shape that is larger than the lower frame 15A and the upper frame 15B that constitute the frame body portion 15, for example. Then, the peripheral edge of the cloth 9 is placed on the cloth receiving portion 19 of the lower frame 15A and pressed by the cloth pressing portion 23 of the upper frame 15B inserted into the frame portion 17 of the lower frame 15A. stretched to have a sufficient tension. Subsequently, while the cloth 9 is stretched with an appropriate tension, the upper frame 15B is pressed against the lower frame 15A by bolting or the like to fix the upper frame 15B, and the outer edge of the cloth 9 is sandwiched so that the outer edge of the cloth 9 is held by the frame body portion 15. portion is held over the entire circumference.

Therefore, the center of the surface of the cloth 9 held by the frame portion 15 facing the lower mold protrusion 5B is the reference position of the upper surface of the lower mold protrusion 5B to which the center (center of gravity) of the thermoplastic resin sheet 3 is to be aligned. , for example, are arranged so as to face each other at the center of the upper surface of the lower mold convex portion 5B. Further, the cloth holding mechanism 7 is provided integrally with the lower die 5 by supporting the frame body portion 15 by the first to fourth frame support portions 16A to 16D. As a result, the height from the cloth 9 stretched between the lower mold 5 and the upper mold 6 with an appropriate tension to the upper surface of the lower mold protrusion 5B is fixed. That is, the lower mold 5 and the upper mold 6 are provided so as to be able to press the thermoplastic resin sheet 3 placed on the cloth 9 while being spaced apart from the lower mold 5 and the upper mold 6 .

For the cloth 9, for example, a polyester fabric woven with polyester fiber, a nylon fabric woven with heat-resistant nylon fiber, a cotton fabric woven with cotton fiber, or the like is appropriately selected according to the temperature at which the thermoplastic resin sheet 3 is heated. can be used as Further, it is desirable that at least the surface of the cloth 9 on the side of the upper mold 6 is raised. Thereby, it is possible to prevent the surface of the heated thermoplastic resin sheet 3 from being textured.

As shown in FIG. 4, before the thermoplastic resin sheet 3 is pressed by the lower die 5 and the upper die 6, the opposite edge portions thereof are clamped by a pair of gripping portions 25, and the cloth holding mechanism 7 is held by the cloth holding mechanism 7. As shown in FIG. and the upper mold 6 and placed in the center of the cloth 9 (see FIG. 6). A pair of gripping portions 25 are arranged facing each other in the horizontal direction orthogonal to the pressing direction, and the thermoplastic resin sheet 3 is moved toward each other and away from each other and retracted out of the mold. (see FIG. 6).

In addition, the pair of gripping portions 25 grips the opposite end edges of the thermoplastic resin sheet 3 over the entire length (indicated by solid lines in FIG. 4), and the opposite end edges of the thermoplastic resin sheet 3 It is configured so that an operation of releasing the grip of the part (indicated by a two-dot chain line in FIG. 4) can be selectively performed. As will be described later, the pair of gripping portions 25 grips the opposite end edges of the heated thermoplastic resin sheet 3 and the cloth 9 held by the cloth holding mechanism 7 by a transport mechanism (not shown). It is conveyed between the upper mold 6 (see the upper left end of FIG. 6). Next, as will be described later, after the gripping of the thermoplastic resin sheet 3 is released, the pair of gripping portions 25 are separated from each other in the horizontal direction to retreat outside the mold, and the thermoplastic resin sheet 3 is placed on the cloth 9 . is placed (see the left end in the lower part of FIG. 6).

Next, the state in which the heated thermoplastic resin sheet 3 is placed on the cloth 9 and positioned will be described with reference to FIG. As shown in FIG. 5 , when the pair of gripping portions 25 are separated from each other in the horizontal direction and retracted outside the mold after releasing the grip of the thermoplastic resin sheet 3 , the substantially central portion on the cloth 9 is The thermoplastic resin sheet 3 is placed on the . Then, the center of the cloth 9 bends due to the weight of the thermoplastic resin sheet 3 , and the force that stabilizes the center (center of gravity) of the thermoplastic resin sheet 3 at the center of the cloth 9 is applied from the cloth 9 to the thermoplastic resin sheet 3 . works.

Thereby, the cloth 9 can position the center (center of gravity) of the thermoplastic resin sheet 3 at the center of the cloth 9 . Further, the center of the cloth 9 held by the cloth holding mechanism 7 is positioned at the reference position on the upper surface of the lower mold protrusion 5B on which the center (center of gravity) of the thermoplastic resin sheet 3 is placed. Therefore, the center (center of gravity) of the thermoplastic resin sheet 3 can be positioned so as to face the center of the upper surface of the lower mold projection 5B.

Further, as shown in FIG. 5, the height of the cloth 9 held by the cloth holding mechanism 7 with respect to the upper surface of the lower mold projection 5B is the lowest end of the cloth 9 bent downward by the weight of the thermoplastic resin sheet 3. A gap of a predetermined height (for example, a height of about 1 cm to 3 cm) is set to be formed between the part and the upper surface of the lower mold convex part 5B. As a result, it is possible to prevent the heat from escaping from the thermoplastic resin sheet 3 to the lower mold 5 and lowering the temperature of the thermoplastic resin sheet 3 until it is pressed.

Next, an example of a procedure (process) for pressing the heated thermoplastic resin sheet 3 by the resin molding apparatus 1 configured as described above will be described with reference to FIG. First, in the process shown at the left end of the upper part of FIG. 6, the pair of gripping portions 25 grips the opposite end edges of the heated thermoplastic resin sheet 3, and is moved to the cloth holding mechanism 7 by the conveying mechanism (not shown). It is conveyed between the held cloth 9 and the upper die 6 . Also, the pair of gripping portions 25 are conveyed so that the center (center of gravity) of the thermoplastic resin sheet 3 faces the substantially central portion of the cloth 9 held by the cloth holding mechanism 7 .

In the process shown in the upper center of FIG. 6, the lower die support portion 11 supports the lower die 5 and the cloth holding mechanism 7 so that the lowermost end of the thermoplastic resin sheet 3 contacts the central portion of the cloth 9. is moved upward by a predetermined height in the pressing direction (vertical direction) by an actuator (not shown). Subsequently, in the process shown at the right end of the upper part of FIG. 6, the pair of gripping portions 25 release the opposite end edges of the thermoplastic resin sheet 3 from gripping.

6, the pair of gripping portions 25 that have released the gripping of the thermoplastic resin sheet 3 are separated from each other in the horizontal direction to the outside of the mold, that is, the cloth holding mechanism 7. Retract to the outside in the horizontal direction. As a result, the center of the cloth 9 is bent by the weight of the thermoplastic resin sheet 3, and the center (the center of gravity) of the thermoplastic resin sheet 3 can be positioned at the center of the cloth 9 (see FIG. 5). That is, the center (center of gravity) of the thermoplastic resin sheet 3 is set to the reference position on the upper surface of the lower mold protrusion 5B on which the center (center of gravity) of the thermoplastic resin sheet 3 is placed. can be positioned so as to face the center of the Moreover, a predetermined height (for example, a height of about 1 cm to 3 cm) is provided between the lowermost end of the cloth 9 bent downward by the weight of the thermoplastic resin sheet 3 and the upper surface of the lower mold protrusion 5B. A gap is formed.

6, the lower die support portion 11 that supports the lower die 5 and the cloth holding mechanism 7 is moved downward in the pressing direction (vertical direction) by a predetermined height by an actuator (not shown). to the origin position. Then, the upper mold supporting portion 12 that supports the upper mold 6 is moved downward in the pressing direction (mold closing direction) by an actuator (not shown), and placed in the center of the cloth 9 away from the lower mold 5 and the upper mold 6 . The thermoplastic resin sheet 3 thus formed is pressed together with the cloth 9 . The cloth 9 is made of a polyester fabric, a nylon fabric, a cotton fabric, or the like, and is set so as to stretch appropriately within the elastic range when the lower mold 5 and upper mold 6 are closed.

As a result, the thermoplastic resin sheet 3 is pressed by the lower mold 5 and the upper mold 6 while sandwiching the cloth 9 between the upper surface of the lower mold protrusion 5B and the lower mold protrusion 5B and the upper mold recess. It is molded into a desired shape corresponding to the shape of 6A. When the lower mold 5 and the upper mold 6 are resin molds, the pressed state is maintained for about 5 minutes, for example. Further, when the lower mold 5 and the upper mold 6 are metal molds such as aluminum alloy, the pressed state is maintained for about 40 to 60 seconds, for example.

Thereafter, in the step shown in the lower right end of FIG. 6, the upper mold support portion 12 that supports the upper mold 6 is moved upward in the pressing direction (mold opening direction) by an actuator (not shown) to be positioned at the origin position. As a result, the press-molded thermoplastic resin sheet 3 is placed on the elastically restored cloth 9 and can be taken out by an operator or a robot hand.

6 to the left end of the lower part of FIG. 6 constitute an example of the sheet placing process. Further, the process shown in the middle of the lower part of FIG. 6 to the process shown in the right end of the lower part of FIG. 6 constitutes an example of the molding process.

As described in detail above, in the resin molding apparatus 1 according to the first embodiment, the heated thermoplastic resin sheet 3 is once placed on the cloth 9 stretched between the lower mold 5 and the upper mold 6. Therefore, the cloth 9 is bent by the weight of the thermoplastic resin sheet 3 , and the center (center of gravity) of the thermoplastic resin sheet 3 moves to the center of the cloth 9 . As a result, the positional deviation of the thermoplastic resin sheet 3 set on the upper surface of the lower mold projection 5B of the lower mold 5 can be corrected, and the shape accuracy of press molding can be improved.

In addition, since the thermoplastic resin sheet 3 placed on the cloth 9 is separated from the upper surface of the lower mold convex portion 5B of the lower mold 5, the thermoplastic resin sheet 3 is separated from the upper surface of the lower mold 5 before being pressed. It is possible to prevent the heat from escaping to the lower mold 5 and lowering the temperature of the thermoplastic resin sheet 3 . Therefore, deterioration of the moldability of the thermoplastic resin sheet 3 can be suppressed.

Further, when the thermoplastic resin sheet 3 placed on the cloth 9 is pressed by the lower mold 5 and the upper mold 6, the upper surface of the lower mold convex portion 5B of the lower mold 5 and the thermoplastic resin sheet 3 Even if air bubbles enter, the air bubbles are discharged from the gap of the cloth 9 arranged between the upper surface of the lower mold projection 5B and the thermoplastic resin sheet 3. Therefore, when the thermoplastic resin sheet 3 placed on the cloth 9 is pressed by the lower mold 5 and the upper mold 6, it is possible to prevent the thermoplastic resin sheet 3 from being distorted due to air bubbles.

Further, the center of the cloth 9 stretched between the lower mold 5 and the upper mold 6 is positioned at the reference position on the upper surface of the lower mold projection 5B on which the center (center of gravity) of the thermoplastic resin sheet 3 is placed. , and the center of the upper surface of the lower mold convex portion 5B of the lower mold 5. Therefore, when the cloth 9 is flexed by the weight of the thermoplastic resin sheet 3 and the center (center of gravity) of the thermoplastic resin sheet 3 moves to the center of the cloth 9, the center of the thermoplastic resin sheet 3 is convex to the lower die. They are arranged so as to face each other at the center of the upper surface of the portion 5B. As a result, the center of the thermoplastic resin sheet 3 can be set at the reference position of the upper surface of the lower mold protrusion 5B, for example, at the center of the upper surface of the lower mold protrusion 5B, and pressed. can be further improved.

Also, the cloth holding mechanism 7 is provided integrally with the lower mold 5 via the lower mold supporting portion 11 so that the cloth 9 stretched between the lower mold 5 and the upper mold 6 extends from the lower mold of the lower mold 5 . The height up to the upper surface of the convex portion 5B is fixed. As a result, there is no need to provide a drive mechanism for moving the cloth 9 up and down, so that the number of parts of the resin molding apparatus 1 can be reduced and the structure can be simplified.

The rectangular cloth 9 has four sides sandwiched from above and below by a frame body portion 15 which is rectangular in plan view and is composed of an upper frame 15B and a lower frame 15A which are rectangular in plan view. It is held all the way around. As a result, when the thermoplastic resin sheet 3 is placed on the cloth 9 , the cloth 9 bends due to the weight of the thermoplastic resin sheet 3 , and the thermoplastic resin sheet 3 moves toward the center of the cloth 9 held by the frame portion 15 . The center (center of gravity) of the resin sheet 3 can be reliably moved.

In addition, since the surface of the cloth 9 on which the thermoplastic resin sheet 3 is placed is raised, when the cloth 9 is pressed by the lower mold 5 and the upper mold 6, the weave of the cloth 9 becomes the surface of the thermoplastic resin sheet 3. It is possible to suppress the sticking, and it is possible to improve the quality.

[Second embodiment]
Next, a second embodiment embodying a resin molding apparatus and a resin molding method according to the present invention will be described with reference to FIGS. 7 and 8. FIG. In the following description, the same reference numerals as in the configuration of the resin molding apparatus 1 according to the first embodiment indicate the same or corresponding parts as the configuration of the resin molding apparatus 1 according to the first embodiment.

The configuration and the like of the resin molding apparatus 31 according to the second embodiment are substantially the same as the configuration and the like of the resin molding apparatus 1 according to the first embodiment. However, as shown in FIG. 7, a frame mounting base 32 is formed in a substantially rectangular frame shape in plan view so as to surround the lower die support portion 11 which is rectangular in plan view and supports the lower die 5 from below. are placed. In addition, the inner center of the frame mounting base 32 in plan view is arranged so as to overlap the center of the upper surface of the lower mold projection 5B at the same position in plan view.

The first frame support portion 16A, the second frame support portion 16B, the third frame support portion 16C, and the fourth frame support portion 16D of the cloth holding mechanism 7 are mounted on the four corner sides of the frame mount base 32. 32 are arranged so that their relative positions do not change, and are different in that they are provided so as to stand along the vertical direction. Therefore, the center of the surface facing the lower projection 5B of the cloth 9 held by the frame portion 15 is the reference of the upper surface of the lower projection 5B on which the center (center of gravity) of the thermoplastic resin sheet 3 is placed. For example, they are arranged so as to face each other at the center of the upper surface of the lower mold convex portion 5B.

Further, by supporting the frame portion 15 by the first to fourth frame support portions 16A to 16D, the cloth holding mechanism 7 is provided separately from the lower mold 5, and the lower mold 5 and the upper mold 6 and is set so that the vertical (vertical) position of the cloth 9 stretched with moderate tension does not change. That is, the lower mold 5 and the upper mold 6 are provided so as to be able to press the thermoplastic resin sheet 3 placed on the cloth 9 while being spaced apart from the lower mold 5 and the upper mold 6 .

Next, an example of a procedure (process) for pressing the heated thermoplastic resin sheet 3 by the resin molding apparatus 31 configured as described above will be described with reference to FIG. First, in the process shown at the left end of the upper part of FIG. 8, the pair of gripping parts 25 grips the opposite end edges of the heated thermoplastic resin sheet 3, and is moved to the cloth holding mechanism 7 by the conveying mechanism (not shown). It is conveyed between the held cloth 9 and the upper die 6 . Also, the pair of gripping portions 25 are conveyed so that the center (center of gravity) of the thermoplastic resin sheet 3 faces the substantially central portion of the cloth 9 held by the cloth holding mechanism 7 .

Then, in the process shown in the upper center of FIG. 8 , the pair of gripping portions 25 are held so that the bottom edge of the thermoplastic resin sheet 3 is in contact with the central portion of the cloth 9 . It is lowered by a conveying mechanism (not shown) while gripping opposite end edges. Subsequently, in the process shown at the right end of the upper part of FIG. 8, the pair of gripping portions 25 are released from gripping the opposite end edges of the thermoplastic resin sheet 3 .

Then, in the step shown in the lower left end of FIG. 8, the pair of gripping portions 25 that have released the gripping of the thermoplastic resin sheet 3 are separated from each other in the horizontal direction to the outside of the mold, that is, the cloth holding mechanism 7. Retract to the outside in the horizontal direction. As a result, the center of the cloth 9 is bent by the weight of the thermoplastic resin sheet 3, and the center (the center of gravity) of the thermoplastic resin sheet 3 can be positioned at the center of the cloth 9 (see FIG. 5). That is, the center (center of gravity) of the thermoplastic resin sheet 3 is set to the reference position on the upper surface of the lower mold protrusion 5B on which the center (center of gravity) of the thermoplastic resin sheet 3 is placed. can be positioned so as to face the center of the Moreover, a predetermined height (for example, a height of about 1 cm to 3 cm) is provided between the lowermost end of the cloth 9 bent downward by the weight of the thermoplastic resin sheet 3 and the upper surface of the lower mold protrusion 5B. A gap is formed.

Subsequently, in the process shown in the lower center of FIG. 8, the lower mold support portion 11 that supports the lower mold 5 is moved upward in the pressing direction (mold closing direction) by an actuator (not shown), and the lower mold protrusion 5B is moved. The upper surface is brought into contact with the cloth 9 over the entire surface. At the same time, the upper mold support portion 12 that supports the upper mold 6 is moved downward in the pressing direction (mold closing direction) by an actuator (not shown) to move the thermoplastic resin sheet 3 placed in the center of the cloth 9 to the cloth. Press with 9. The cloth 9 is made of a polyester fabric, a nylon fabric, a cotton fabric, or the like, and is set so as to stretch appropriately within the elastic range when the lower mold 5 and upper mold 6 are closed.

As a result, the thermoplastic resin sheet 3 is pressed by the lower mold 5 and the upper mold 6 while sandwiching the cloth 9 between the upper surface of the lower mold protrusion 5B and the lower mold protrusion 5B and the upper mold recess. It is molded into a desired shape corresponding to the shape of 6A. When the lower mold 5 and the upper mold 6 are resin molds, the pressed state is maintained for about 5 minutes, for example. Further, when the lower mold 5 and the upper mold 6 are metal molds such as aluminum alloy, the pressed state is maintained for about 40 to 60 seconds, for example.

Thereafter, in the step shown in the lower right end of FIG. 8, the upper die support portion 12 that supports the upper die 6 is moved upward in the press direction (mold opening direction) by an actuator (not shown) and positioned at the origin position. In addition, the lower die support portion 11 that supports the lower die 5 is moved downward in the pressing direction (mold opening direction) by an actuator (not shown) to be positioned at the origin position. As a result, the press-molded thermoplastic resin sheet 3 is placed on the elastically restored cloth 9 and can be taken out by an operator or a robot hand.

Here, the process shown on the left end of the upper part of FIG. 8 to the process shown on the left end of the lower part of FIG. Further, the process shown in the center of the lower part of FIG. 8 to the process shown on the right end of the lower part of FIG. 8 constitutes an example of the molding process.

As described in detail above, in the resin molding apparatus 31 according to the second embodiment, the heated thermoplastic resin sheet 3 is once placed on the cloth 9 stretched between the lower mold 5 and the upper mold 6. Therefore, the cloth 9 is bent by the weight of the thermoplastic resin sheet 3 , and the center (center of gravity) of the thermoplastic resin sheet 3 moves to the center of the cloth 9 . As a result, the positional deviation of the thermoplastic resin sheet 3 set on the upper surface of the lower mold projection 5B of the lower mold 5 can be corrected, and the shape accuracy of press molding can be improved.

In addition, since the thermoplastic resin sheet 3 placed on the cloth 9 is separated from the upper surface of the lower mold convex portion 5B of the lower mold 5, the thermoplastic resin sheet 3 is separated from the upper surface of the lower mold 5 before being pressed. It is possible to prevent the heat from escaping to the lower mold 5 and lowering the temperature of the thermoplastic resin sheet 3 . Therefore, deterioration of the moldability of the thermoplastic resin sheet 3 can be suppressed.

Further, when the thermoplastic resin sheet 3 placed on the cloth 9 is pressed by the lower mold 5 and the upper mold 6, the upper surface of the lower mold convex portion 5B of the lower mold 5 and the thermoplastic resin sheet 3 Even if air bubbles enter, the air bubbles are discharged from the gap of the cloth 9 arranged between the upper surface of the lower mold projection 5B and the thermoplastic resin sheet 3. Therefore, when the thermoplastic resin sheet 3 placed on the cloth 9 is pressed by the lower mold 5 and the upper mold 6, it is possible to prevent the thermoplastic resin sheet 3 from being distorted due to air bubbles.

Further, the center of the cloth 9 stretched between the lower mold 5 and the upper mold 6 is positioned at the reference position on the upper surface of the lower mold projection 5B on which the center (center of gravity) of the thermoplastic resin sheet 3 is placed. , the center of the upper surface of the lower mold convex portion 5B of the lower mold 5 faces the center of the upper surface of the lower mold 5B, the cloth 9 is bent by the weight of the thermoplastic resin sheet 3, and the center (center of gravity) of the thermoplastic resin sheet 3 moves to the center of the cloth 9. When moved, the center of the thermoplastic resin sheet 3 is arranged so as to face the center of the upper surface of the lower mold projection 5B. As a result, the center of the thermoplastic resin sheet 3 can be set at the reference position of the upper surface of the lower mold protrusion 5B, for example, at the center of the upper surface of the lower mold protrusion 5B, and pressed. can be further improved.

In addition, the cloth holding mechanism 7 is supported on a frame mounting base 32 formed in a rectangular frame shape in a plan view and arranged so as to surround the lower die support portion 11, and is provided separately from the lower die 5. It is set so that the vertical position of the cloth 9 stretched between the lower mold 5 and the upper mold 6 does not change. Thereby, the vertical height of the cloth 9 can be adjusted independently, and the vertical height of the cloth 9 can be easily adjusted.

The rectangular cloth 9 has four sides sandwiched from above and below by a frame body portion 15 which is rectangular in plan view and is composed of an upper frame 15B and a lower frame 15A which are rectangular in plan view. It is held all the way around. As a result, when the thermoplastic resin sheet 3 is placed on the cloth 9 , the cloth 9 bends due to the weight of the thermoplastic resin sheet 3 , and the thermoplastic resin sheet 3 moves toward the center of the cloth 9 held by the frame portion 15 . The center (center of gravity) of the resin sheet 3 can be reliably moved.

In addition, since the surface of the cloth 9 on which the thermoplastic resin sheet 3 is placed is raised, when the cloth 9 is pressed by the lower mold 5 and the upper mold 6, the weave of the cloth 9 becomes the surface of the thermoplastic resin sheet 3. It is possible to suppress the sticking, and it is possible to improve the quality.

The resin molding apparatus and resin molding method of the present invention are not limited to the configuration, structure, appearance, shape, processing procedure, etc. described in the first and second embodiments, and the gist of the present invention is changed. Various changes, improvements, additions, and deletions are possible within the scope of the invention. In the following description, the same reference numerals as those of the resin molding apparatus 1, resin molding apparatus 31, etc. in FIGS.

(A) For example, in the upper mold 6 of the resin molding apparatus 1 and the resin molding apparatus 31, the cloth 9 may be attached over the entire lower surface of the upper mold concave portion 6A. As a result, when the thermoplastic resin sheet 3 placed on the cloth 9 is pressed by the lower mold 5 and the upper mold 6, a gap between the lower surface of the upper mold concave portion 6A of the upper mold 6 and the thermoplastic resin sheet 3 is formed. Even if air bubbles enter, the air bubbles are discharged from the gap of the cloth 9 arranged between the lower surface of the upper mold recess 6A and the thermoplastic resin sheet 3. Therefore, when the thermoplastic resin sheet 3 placed on the cloth 9 held by the cloth holding mechanism 7 is pressed by the lower mold 5 and the upper mold 6, the generation of distortion due to air bubbles in the thermoplastic resin sheet 3 is further reduced. can be suppressed.

Furthermore, it is desirable that the surface of the cloth 9, which is attached to the entire lower surface of the upper mold recess 6A and faces the lower mold 5, is raised. As a result, it is possible to prevent the surface of the heated thermoplastic resin sheet 3 on the side of the upper die 6 from being textured.

(B) Further, for example, in the procedure (step) shown in FIG. 6 for pressing the thermoplastic resin sheet 3 heated by the resin molding apparatus 1, the lower mold 5 and the cloth holder The lower mold support portion 11 that supports the mechanism 7 may not be moved upward in the pressing direction (vertical direction). Then, with the pair of gripping portions 25 gripping opposite end edges of the heated thermoplastic resin sheet 3 so that the lowermost edge of the thermoplastic resin sheet 3 contacts the central portion of the cloth 9, It may be lowered by a transport mechanism (not shown).

Subsequently, in the process shown in the right end of the upper part of FIG. 6, the gripping of the opposite end edges of the thermoplastic resin sheet 3 by the pair of gripping portions 25 may be released. 6, the pair of gripping portions 25 that have released the gripping of the thermoplastic resin sheet 3 are separated from each other in the horizontal direction to the outside of the mold, that is, the cloth holding mechanism 7. It may be retracted to the outside in the horizontal direction.

As a result, the center of the cloth 9 is bent by the weight of the thermoplastic resin sheet 3, and the center (the center of gravity) of the thermoplastic resin sheet 3 can be positioned at the center of the cloth 9 (see FIG. 5). That is, the center (center of gravity) of the thermoplastic resin sheet 3 can be positioned so as to face the center of the upper surface of the lower mold projection 5B. Moreover, a predetermined height (for example, a height of about 1 cm to 3 cm) is provided between the lowermost end of the cloth 9 bent downward by the weight of the thermoplastic resin sheet 3 and the upper surface of the lower mold protrusion 5B. A gap is formed.

Subsequently, in the step shown in the center of the lower part of FIG. 6, the upper mold support portion 12 that supports the upper mold 6 is moved downward in the pressing direction (mold closing direction) by an actuator (not shown), and the lower mold 5 and the upper mold The thermoplastic resin sheet 3 placed in the center of the cloth 9 apart from the cloth 9 may be pressed together with the cloth 9 . 6, the upper mold supporting portion 12 for supporting the upper mold 6 is moved upward in the pressing direction (mold opening direction) by an actuator (not shown) so as to be positioned at the origin position. may

As a result, the lower mold supporting portion 11 that supports the lower mold 5 and the cloth holding mechanism 7 is positioned at the origin position in all the steps from the left end of the upper part of FIG. 6 to the right end of the lower part of FIG. be able to. Therefore, it is possible to omit the actuator for moving the lower die support portion 11 that supports the lower die 5 and the cloth holding mechanism 7 upwardly and downwardly in the pressing direction. can be further simplified.

Reference Signs List 1, 31 resin molding device 3 thermoplastic resin sheet 5 lower mold 6 upper mold 7 cloth holding mechanism 9 cloth 15 frame body portion 15A lower frame 15B upper frame

Claims (7)

A resin molding device for molding a heated thermoplastic resin sheet,
lower mold;
an upper mold for pressing the thermoplastic resin sheet between the lower mold;
a cloth holding mechanism provided around the lower mold and holding the cloth stretched between the lower mold and the upper mold;
with
The cloth is stretched between the lower mold and the upper mold so as to be spaced apart from the lower mold and the upper mold and perpendicular to the pressing direction of the lower mold and the upper mold,
The lower mold and the upper mold are provided so as to be able to press the thermoplastic resin sheet placed on the cloth at a distance from the lower mold and the upper mold.
Resin molding equipment. In the resin molding apparatus according to claim 1,
In the cloth holding mechanism, the center of the cloth stretched between the lower mold and the upper mold faces a reference position on the upper surface of the lower mold on which the center of the thermoplastic resin sheet is placed. holding said cloth in such a way that
Resin molding equipment. In the resin molding apparatus according to claim 1 or claim 2,
The cloth holding mechanism is provided integrally with the lower mold, and the height of the cloth stretched between the lower mold and the upper mold from the upper surface of the lower mold is fixed.
Resin molding equipment. In the resin molding apparatus according to claim 1 or claim 2,
The cloth holding mechanism is provided separately from the lower mold, and is set so that the vertical position of the cloth stretched between the lower mold and the upper mold does not change.
Resin molding equipment. In the resin molding apparatus according to any one of claims 1 to 4,
The cloth holding mechanism has a frame portion that sandwiches and holds the cloth from above and below,
The frame body part
a lower frame on which the cloth is placed;
an upper frame attached to the lower frame with the cloth interposed therebetween;
having
Resin molding equipment. In the resin molding apparatus according to any one of claims 1 to 5,
The cloth has a raised surface on which the thermoplastic resin sheet is placed,
Resin molding equipment. A resin molding method for molding the thermoplastic resin sheet using the resin molding apparatus according to claim 1,
a sheet placing step of placing the heated thermoplastic resin sheet on the central portion of the cloth;
a molding step of pressing the thermoplastic resin sheet placed on the cloth with the lower mold and the upper mold apart from the lower mold and the upper mold in the sheet placing step;
with
Resin molding method.

Images