CN111791468B

CN111791468B - Resin molding apparatus and resin molding method

Info

Publication number: CN111791468B
Application number: CN202010228621.0A
Authority: CN
Inventors: 金口豊也
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2019-04-04
Filing date: 2020-03-27
Publication date: 2022-06-17
Anticipated expiration: 2040-03-27
Also published as: CN111791468A; JP2020168820A; JP7044735B2

Abstract

The invention provides a resin molding apparatus and a resin molding method, which can restrain the resin sheet from deviating relative to the mold. The resin molding apparatus includes: a holder for supporting an edge of the resin sheet and horizontally arranging the resin sheet; a mold provided below the holder so as to be movable relative to the holder in the vertical direction, the mold having a molding surface facing upward; a compressed air tank which is provided above the holder so as to be movable relative to the holder in the vertical direction and which is capable of sandwiching the resin sheet between the compressed air tank and the mold; a lower plate which is provided movably in the vertical direction and the horizontal direction with respect to the holder, supports the lower surface of the resin sheet, and heats the resin sheet; a plug provided on a lower surface of the compressed air tank and pressing an upper surface of the resin sheet downward; and a compressed air supply device which supplies compressed air to the lower surface of the compressed air box so as to enable the resin sheet to be in close contact with the molding surface.

Description

Resin molding apparatus and resin molding method

Technical Field

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

Background

Such a resin molding apparatus (compressed air molding apparatus) is known: the resin sheet is heated and softened above a mold having a molding surface facing upward, and compressed air is supplied to the upper surface side of the resin sheet to bring the softened resin sheet into close contact with the molding surface, thereby molding the resin sheet (for example, patent document 1).

Documents of the prior art

Patent document 1: international publication No. 2017/047564

Disclosure of Invention

Problems to be solved by the invention

In the above resin molding apparatus, a phenomenon of drawdown (draw down) occurs in which the resin sheet softened by heating hangs down due to its own weight. The shape of the resin sheet when the sagging occurs changes in accordance with the variation in the amount of heating and the variation in the distribution of heating. Therefore, there is a problem that a portion of the resin sheet which first comes into contact with the molding surface of the mold changes, and the position of the resin sheet with respect to the mold varies. When the surface of the resin sheet is printed, the shape of the molded article and the printing may be deviated, which is particularly problematic.

In view of the above background, an object of the present invention is to provide a resin molding apparatus and a resin molding method capable of suppressing displacement of a resin sheet with respect to a mold.

Means for solving the problems

In order to solve the above problem, one aspect of the present invention is a resin molding apparatus 1 including: a holder 5 for supporting an edge of a resin sheet M and horizontally arranging the resin sheet; a mold 3 provided below the holder so as to be movable relative to the holder in the vertical direction, and including an upward molding surface 3A; a compressed air tank 4 provided above the holder so as to be movable relative to the holder in a vertical direction, the compressed air tank being capable of sandwiching the resin sheet between the compressed air tank and the mold; a lower plate 6 which is provided so as to be movable in the vertical direction and the horizontal direction with respect to the holder, supports the lower surface of the resin sheet, and heats the resin sheet; a plug 8 provided on a lower surface of the compressed air tank and pressing an upper surface of the resin sheet downward; and a compressed air supply device 19 that supplies compressed air to a lower surface of the compressed air tank to bring the resin sheet into close contact with the molding surface.

According to this embodiment, since the lower plate supports the lower surface of the heated resin sheet, sagging of the resin sheet can be eliminated, and the inclusion shape of the softened resin sheet at the time of starting molding can be fixed. Further, since the positional deviation of the softened resin sheet is reduced by the plug, the positional deviation of the resin sheet with respect to the mold can be reduced. In particular, when a pattern such as a pattern is printed on a resin sheet, the shape and the position of the pattern can be accurately matched.

In the above aspect, a protrusion 8C for locking the resin sheet may be provided at a lower end of the plug.

According to this aspect, since the projection locks the softened resin sheet, the positional displacement of the resin sheet with respect to the mold can be further reduced. For example, by providing a projection at a portion where reduction of positional deviation is particularly desired, such as the center portion of the resin sheet, positional deviation of the portion can be reduced appropriately.

In the above aspect, after the plug is lowered with respect to the holder and brought into contact with the upper surface of the resin sheet, the lower plate may be lowered with respect to the holder while sandwiching the resin sheet between the lower plate and the plug in accordance with the lowering of the plug.

According to this aspect, the contact range can be gradually widened around the first contact portion between the plug and the resin sheet, and the positional displacement of the resin sheet with respect to the contact portion of the plug can be reduced. This can reduce the positional deviation of the vicinity of the contact portion of the resin sheet with the plug with respect to the mold.

In the above aspect, the lower plate may be moved away in the horizontal direction from below the resin sheet after being lowered by a predetermined distance.

According to this aspect, when the lower plate is retracted, the contact area between the lower plate and the resin sheet can be reduced. This can reduce the tensile force in the horizontal direction of the resin sheet due to the magic force, and can reduce the positional deviation of the resin sheet in the horizontal direction with respect to the mold.

In the above aspect, the plug may be lowered with respect to the mold to a position where the resin sheet is sandwiched between the plug and the molding surface.

According to this aspect, since the mold plug sandwiches the resin sheet between the mold surface and the mold, it is possible to suppress positional deviation of the portion of the resin sheet to be nipped. Further, since the resin sheet can be arranged in the vicinity of the molding surface before the compressed air is supplied, the amount of movement of the resin sheet to the molding surface when the compressed air is supplied can be reduced, and the positional deviation of the entire resin sheet with respect to the molding surface can be reduced.

In the above aspect, the lower plate may generate joule heat by receiving supply of electric current.

According to this aspect, the lower plate that has a smooth upper surface and can be heated can be formed with a simple structure.

In the above embodiment, the lower plate may be replaced with a plate 52 and a heater 51 disposed below the plate. In this case, the plate may be provided so as to be movable relative to the heater in the vertical direction, and a compression spring 56 may be provided between the plate and the heater.

According to these aspects, the lower plate can be simply configured. Further, when the plug further lowers while sandwiching the resin sheet with the plate portion, the plate portion can be lowered relative to the heat-generating body in accordance with the lowering of the plug. This makes it possible to omit a moving device for lowering the plate in accordance with the lowering of the plug.

In the above aspect, the resin molding apparatus may include an upper heating device movable between a heating position located above the resin sheet supported by the holder and a retracted position retracted horizontally from the heating position so that the plug can be lowered.

According to this aspect, the resin sheet can be efficiently heated from the top and bottom.

In the above aspect, the resin molding apparatus may include: a heating device 61 disposed on the side of the compressed air tank and the mold, for heating the resin sheet; and a conveying device 62 that conveys the resin sheet heated by the heating device to the holder.

According to this aspect, the number of components disposed between the compressed air tank and the mold can be reduced, and the apparatus can be simplified. Further, a large-sized heating device can be used, and the resin sheet can be uniformly heated.

In the above aspect, the plug may be configured to be temperature-adjustable.

According to this aspect, a temperature drop of the resin sheet due to contact with the plug can be reduced.

In the above aspect, a pattern may be printed on a surface of the resin sheet. Further, the pattern may be printed on the upper surface of the resin sheet.

According to this embodiment, a pattern or the like can be formed on the surface of the molded article. Further, by printing a pattern on the upper surface of the resin sheet, contact between the lower plate having a high temperature and the printing can be avoided. This can suppress the elution of ink from the pattern and the adhesion of the resin sheet to the lower plate due to the ink.

In the above aspect, there may be provided a resin molding method for molding a resin molded product P from a resin sheet M, including: a first step of supporting an edge of the resin sheet by a holder 5 and supporting a lower surface of the resin sheet by a lower plate 6, and horizontally arranging the resin sheet above a mold 3 with a molding surface 3A facing upward; a second step of heating the resin sheet by the lower plate; a third step of bringing a lower end portion 8B of a die plug 8 provided on a lower surface of a compressed air tank into contact with an upper surface of the resin sheet and sandwiching the resin sheet between the lower plate and the lower plate; a fourth step of lowering the plug and the lower plate relative to the holder while maintaining the position of the holder, and bringing the resin sheet into close contact with the surface of the plug; a fifth step of horizontally retracting the lower plate; a sixth step of moving the compressed air tank and the mold relative to the holder in a vertical direction to sandwich the resin sheet between the compressed air tank and the mold; and a seventh step of supplying compressed air to a lower surface of the compressed air tank to bring the resin sheet into close contact with the molding surface.

According to this embodiment, sagging of the resin sheet can be eliminated, and the state including the shape of the softened resin sheet at the time of starting molding can be fixed. Further, since the positional deviation of the softened resin sheet is reduced by the plug, the positional deviation of the resin sheet with respect to the mold can be reduced. In particular, when a pattern such as a pattern is printed on a resin sheet, the shape and the position of the pattern can be accurately matched.

In the above aspect, in the sixth step, the mold may sandwich the resin sheet between the mold plug and the molding surface.

In the above aspect, a protrusion 8C may be provided at a lower end of the plug, and the protrusion may lock the resin sheet in the third step.

According to this aspect, since the projection locks the softened resin sheet, it is possible to reduce the positional deviation of the resin sheet with respect to the mold. For example, by providing a projection at a portion where reduction of positional deviation is particularly desired, such as the center portion of the resin sheet, positional deviation of the portion can be reduced appropriately.

Effects of the invention

According to the above configuration, it is possible to provide a resin molding apparatus and a resin molding method capable of suppressing the displacement of the resin sheet with respect to the mold.

Drawings

Fig. 1 is an explanatory view showing an initial state of a resin molding apparatus according to a first embodiment.

Fig. 2 is a front view of the plug.

Fig. 3 is a side view of the plug.

Fig. 4 is a block diagram of a control device of the resin molding device.

Fig. 5 is an explanatory diagram illustrating a state of the resin molding apparatus in the second step of the resin molding method.

Fig. 6 is an explanatory diagram illustrating a state of the resin molding apparatus in the third step of the resin molding method.

Fig. 7 is an explanatory view showing a state of the resin molding apparatus in the fourth step of the resin molding method.

Fig. 8 is an explanatory diagram illustrating a state of the resin molding apparatus in the fifth step of the resin molding method.

Fig. 9 is an explanatory diagram illustrating a state of the resin molding apparatus in the sixth step of the resin molding method.

Fig. 10 is an explanatory view showing a state of the resin molding apparatus in the seventh step of the resin molding method.

Fig. 11 is an explanatory view showing a state of the resin molding apparatus according to the second embodiment in the third step.

Fig. 12 is an explanatory view showing a state of the resin molding apparatus according to the second embodiment in the fourth step.

Fig. 13 is an explanatory view showing a resin molding apparatus according to a third embodiment.

Description of the reference symbols

1. 50, 60: a resin molding device;

2: a base station;

3: a mold;

3A: molding surface;

3B: shoulder surface;

4: a compressed air tank;

5: a holder;

6: a lower plate;

6A: an upper surface;

7: an upper heater;

8: a mold plug;

8A: a lower surface;

8B: a lower end portion;

8C: a protrusion;

9: a lower lifting device;

11: an air passage;

13: a lower moving device;

14: an upper moving device;

16: an ascending and descending device;

18: a compressed air passage;

19: a compressor;

20: a control device;

51: a heater;

52: a plate;

56: a compression spring;

61: a heating device;

62: a conveying device;

m: a resin sheet.

Detailed Description

Hereinafter, an embodiment of the resin molding apparatus 1 according to the present invention will be described with reference to the drawings. The resin molding apparatus 1 heats and softens a resin sheet M as a material, and molds the resin sheet M by bringing the resin sheet M into close contact with a mold with compressed air. The resin molding apparatus 1 is a so-called compressed air molding apparatus. The resin sheet M is a sheet made of a thermoplastic material such as polycarbonate, acrylic resin, and ABS. The thickness of the resin sheet M may be, for example, 0.3mm to 20 mm. Patterns such as designs and figures may be printed on the surface of the resin sheet M. For example, when the resin molding apparatus 1 is used to mold a tailgate of a vehicle, a pattern corresponding to a logo, a stop lamp, a high-mount stop lamp, a turn signal lamp, a rear window, or the like may be printed on a resin sheet M that is a material of the tailgate. The pattern may be colored corresponding to each structure. The pattern may be printed by, for example, screen printing.

As shown in fig. 1, the resin molding apparatus 1 includes a base 2, a mold 3, a compressed air tank 4, a holder 5, a lower plate 6, an upper heater 7 (upper heating device), and plugs 8 and 15. The base 2 is a structure formed by combining a frame and a panel.

The holder 5 supports the edge of the resin sheet M and horizontally arranges the resin sheet M. The holder 5 is, for example, a clip, has a lower member 5A and an upper member 5B that are movable relative to each other up and down, and sandwiches an edge portion of the resin sheet M between the upper member 5B and the lower member 5A. The holder 5 supports at least the mutually opposite edge portions of the resin sheet M. In the present embodiment, the lower member 5A and the upper member 5B are each formed in a rectangular frame shape, and sandwich the entire periphery of the edge of the resin sheet M. The upper member 5B and the lower member 5A each have a horizontal plate-like portion formed in a frame shape and a vertical wall portion vertically standing along the inner periphery of the plate-like portion, and the upper member 5B and the lower member 5A are formed in an L-shape in cross section. The lower member 5A is fixed to the base 2, and the upper member 5B is provided on the base 2 so as to be movable in the vertical direction. In another embodiment, the lower member 5A and the upper member 5B may be provided on the base 2 so as to be movable in the vertical direction. For example, the lower member 5A and the upper member 5B of the holder 5 may be supported by rails (not shown) extending in the vertical direction provided on the base 2 and may be moved up and down by the driving force of an electric motor (not shown).

The mold 3 is supported by the base 2 via a lower lifting device 9. The mold 3 is provided below the holder 5 so as to be movable relative to the holder 5 in the vertical direction. The upper part of the mold 3 is provided with an upward molding surface 3A. A shoulder surface 3B is provided around the molding surface 3A. The shoulder surface 3B is an upward horizontal surface, and surrounds the molding surface 3A over the entire circumference. The molding surface 3A is recessed downward with respect to the shoulder surface 3B. An air passage 11 is formed inside the mold 3. The air passage 11 has a collective passage 11A and a plurality of branch passages 11B branched from one end of the collective passage 11A. Each branch passage 11B opens to the molding surface 3A, and the collective passage 11A opens to the lower surface of the mold 3. The end of the collection passage 11A may be connected to a suction pump via a tube or the like.

The lower lifting device 9 moves the mold 3 in the vertical direction with respect to the base 2. The lower lift device 9 has a rod extending vertically from the lower portion of the base 2. The mold 3 is mounted on the upper end of the rod of the lower lifting device 9. The rod of the lower lift device 9 is driven by, for example, an electric motor or a power cylinder, and moves up and down with respect to the base 2. The mold 3 is movable relative to the holder 5 in the vertical direction by the lower lifting device 9.

The lower plate 6 is supported by a lower moving device 13 provided on the base 2, and the lower plate 6 faces upward and downward. The lower moving device 13 is provided on the base 2 and is movable in the vertical direction and the horizontal direction with respect to the base 2. That is, the lower plate 6 is provided to be movable in the vertical direction and the horizontal direction with respect to the holder 5. The lower moving device 13 is disposed above the mold 3 and below the holder 5. The lower moving device 13 supports the edge of the lower plate 6. The lower plate 6 is provided above the mold 3 so as to be movable in the vertical direction and the horizontal direction with respect to the mold 3 by the lower moving device 13.

The upper surface 6A of the lower plate 6 is formed as a smooth horizontal surface. The upper surface 6A of the lower plate 6 can horizontally support the lower surface of the resin sheet M. The lower plate 6 is heated to heat the resin sheet M. In the present embodiment, the lower plate 6 is a metal plate that generates joule heat upon receiving supply of electric current.

The upper heater 7 is supported by an upper moving device 14 provided on the base 2, and the upper heater 7 faces upward and downward. The upper moving device 14 is provided on the base 2 and is movable at least in the horizontal direction with respect to the base 2. The upper moving device 14 may be movable in the vertical direction with respect to the base 2 in addition to the horizontal direction. The upper moving device 14 is disposed above the holder 5. The upper transfer device 14 supports the edge of the upper heater 7. The upper heater 7 is movable by the upper moving device 14 between a heating position above the resin sheet M supported by the holder 5 and a retracted position that is horizontally retracted from the heating position and does not overlap the resin sheet M in the vertical direction.

The upper heater 7 is disposed above the resin sheet M supported by the holder 5 by the upper moving device 14. The upper heater 7 includes a heat conductive wire that generates heat by receiving a current. The upper heater 7 can heat the resin sheet M from above.

The lower moving device 13 and the upper moving device 14 are driven by electric motors, respectively. The lower moving device 13 and the upper moving device 14 may be each configured by, for example, a moving mechanism having a rail and a slider supported by the rail, or a moving mechanism having a feed screw.

The compressed air tank 4 is a structure that can form a space between the compressed air tank and the molding surface 3A in cooperation with the mold 3 and supply compressed air to the formed space. The compressed air tank 4 is formed in a horizontal plate shape, and is supported by the base 2 so as to be movable in the vertical direction by the elevating device 16. The upper lift device 16 has a rod extending vertically from the upper portion of the base 2. The compressed air tank 4 is installed at the lower end of the rod of the upper lift device 16. The rod of the upper lift device 16 is driven by, for example, an electric motor or a power cylinder, and moves up and down with respect to the base 2. The edge of the lower surface 4A of the compressed air tank 4 is formed in a shape corresponding to the shoulder surface 3B of the mold 3 over the entire circumference. Thereby, the edge of the lower surface 4A of the compressed air tank 4 can sandwich the resin sheet M over the entire circumference with the shoulder surface 3B of the mold 3. The compressed air tank 4 can close the recess formed by the molding surface 3A of the mold 3 through the resin sheet M.

Fig. 2 is a front view of the plug 8, and fig. 3 is a right side view of the

plugs

8 and 15. As shown in fig. 3 and 4, the

plugs

8 and 15 are provided on the lower surface 4A of the compressed air tank 4. The

plugs

8 and 15 protrude downward from the lower surface 4A of the compressed air tank 4. The shape of the

plugs

8 and 15 can be set as appropriate according to the shape of the molded article and the mold 3. The number of the plugs 8 is one or more, and the second plug 15 having a height lower than that of the first plug 8 may be provided at a distance from the first plug 8 as in the present embodiment. In the present embodiment, the first plug 8 is formed to have a lateral width larger than a front-rear width. Each of the

plugs

8, 15 may be provided at a portion of the resin sheet M where it is desired to suppress positional deviation in the horizontal direction. For example, in the case of forming the tailgate with the resin sheet M, the first plug 8 may be provided corresponding to a central portion (e.g., a portion provided with a logo) of the resin sheet M, and the second plug 15 may be provided corresponding to a portion (e.g., a portion provided with a high-attachment tape) deviated from the central portion of the resin sheet M.

As shown in fig. 3, the lower surface 8A of the first plug 8 may be formed as an inclined surface inclined toward the lower end portion 8B projecting most downward. The lower end 8B is preferably pointed. Further, the lower end portion 8B is preferably provided with a protrusion 8C protruding downward with respect to the lower surface 8A. The height of the protrusion 8C (the protruding length from the lower surface 8A) is preferably smaller than the thickness of the resin sheet M. The plugs 8 and 15 provided in the compressed air tank 4 can be moved upward relative to the mold 3 by driving the ascending/descending device 16. The plug 8 is lowered to press the upper surface of the resin sheet M downward.

Each of the

plugs

8 and 15 may be configured to be capable of temperature adjustment. For example, each of the

plugs

8 and 15 may be made of a metal that generates joule heat by the passage of electric current. The

plugs

8 and 15 may be provided with heaters for generating joule heat by energization at their side portions or inside.

As shown in fig. 1, a compressed air passage 18 is formed inside the compressed air tank 4 and the plug 8. The compressed air passage 18 has a collecting passage 18A and a plurality of branch passages 18B branched from one end of the collecting passage 18A. The branch passages 18B open to the lower surface 4A of the compressed air tank 4 and the lower surface 8A of the plug 8, and the collective passage 18A opens to the upper surface of the compressed air tank 4. An end of the collecting passage 18A is connected to a compressor 19 as a compressed air supply device via a pipe or the like. In order to bring the resin sheet M into close contact with the molding surface 3A in a state where the resin sheet M is sandwiched between the die 3 and the compressed air tank 4, the compressor 19 supplies compressed air to the upper side of the resin sheet M via the compressed air passage 18.

As shown in fig. 4, the holder 5, the lower lifting device 9, the upper lifting device 16, the lower moving device 13, the upper moving device 14, the compressor 19, the upper heater 7, and the lower plate 6 are controlled by the control device 20.

Next, a resin molding method (compressed air molding method) for molding a resin molded article from a resin sheet M using the resin molding apparatus 1 will be described. As shown in fig. 1, as a first step, the controller 20 controls the holder 5 to clamp the edge of the resin sheet M between the lower member 5A and the upper member 5B of the holder 5. When a pattern is printed on the surface of the resin sheet M, the surface on which the pattern is printed may be the upper surface. The controller 20 controls the lower moving device 13 to dispose the lower plate 6 at a position abutting on the lower surface of the resin sheet M. Thereby, the resin sheet M is placed on the upper surface of the lower plate 6 and horizontally disposed above the mold 3 with the molding surface 3A facing upward. At this time, the controller 20 controls the upper moving device 14 to dispose the upper heater 7 at the heating position above the resin sheet M.

Next, as a second step, the controller 20 supplies electric power to the lower plate 6 and the upper heater 7 to heat them. Thereby, the resin sheet M is heated and softened by the lower plate 6 and the upper heater 7. At this time, since the resin sheet M is supported by the upper surface 6A of the lower plate 6, even if the resin sheet M is softened, the resin sheet M does not sag. When the resin sheet M is heated by the upper heater 7, as shown in fig. 5, the control device 20 drives the upper moving device 14 after a predetermined heating time has elapsed, and moves the upper heater 7 from the heating position to the retreat position on the side (the back side or the front side of the paper surface). By moving the upper heater 7 to the retreat position, the plug 8 and the compressed air tank 4 can be lowered with respect to the holder 5.

Next, as a third step, the controller 20 controls the ascending/descending device 16 to descend the compressed air tank 4 and the plug 8, and as shown in fig. 6, brings the lower end 8B of the plug 8 into contact with the upper surface of the resin sheet M, and sandwiches the resin sheet M between the lower end 8B of the plug 8 and the lower plate 6. Thereby, the movement of the resin sheet M in the horizontal direction is suppressed. When the projection 8C is provided at the lower end portion 8B, the projection 8C engages with the resin sheet M, thereby further suppressing the movement of the resin sheet M in the horizontal direction. The protrusions 8C may be, for example, embedded in or penetrated into the resin sheet M in a range where the holes are not formed in the resin sheet M.

Next, as a fourth step, the controller 20 controls the upper and lower moving

devices

16 and 13 to lower the plug 8 and the lower plate 6 relative to the holder 5 while maintaining the position of the holder 5. As a result, as shown in fig. 7, the resin sheet M is pushed downward by the lower surface 8A of the plug 8, and the resin sheet M is extended and brought into close contact with the lower surface 8A of the plug 8. Thereby, the movement of the resin sheet M in the horizontal direction is suppressed by the frictional force generated between the resin sheet M and the lower surface 8A of the plug 8.

Next, as a fifth step, as shown in fig. 8, the control device 20 controls the lower moving device 13 to move the lower plate 6 to the retracted position on the side (the back side or the front side of the paper surface). The lower plate 6 is moved to the retracted position, and thereby the lower plate 6 does not overlap with the resin sheet M, the holder 5, and the mold 3 in the vertical direction. Therefore, the mold 3 can be raised with respect to the resin sheet M and the holder 5. When the lower plate 6 is moved to the retracted position, the control device 20 may move the lower plate 6 to the retracted position on the side after lowering the lower plate 6 by a predetermined distance with respect to the resin sheet M. This can avoid sliding contact between the lower plate 6 and the resin sheet M, and can eliminate positional displacement of the resin sheet M in the horizontal direction caused by retraction of the lower plate 6.

Next, as a sixth step, as shown in fig. 9, the controller 20 controls the lower lifting device 9 to lower the compressed air tank 4 until the mold 3 sandwiches the resin sheet M between the compressed air tank 4 and the mold. Thereby, the resin sheet M is sandwiched between the edge of the lower surface 4A of the compressed air tank 4 and the shoulder surface 3B of the mold 3, and the recess formed by the molding surface 3A is closed by the compressed air tank 4. At this time, it is preferable that the lower end 8B of the plug 8 sandwich the resin sheet M between itself and the molding surface 3A. By setting the height of the plug 8 to be larger than a value obtained by subtracting the thickness of the resin sheet M from the depth of the molding surface 3A and setting the height of the plug 8 to be smaller than the depth of the molding surface 3A, when the lower surface 4A of the compressed air tank 4 abuts against the shoulder surface 3B of the mold 3 through the resin sheet M, the resin sheet M can be sandwiched between the plug 8 and the molding surface 3A.

Next, as a seventh step, the controller 20 drives the compressor 19 to supply compressed air to the lower surface 4A of the compressed air tank 4 and the lower surface 8A of the plug 8 via the compressed air passage 18. As a result, as shown in fig. 10, the softened resin sheet M is brought into close contact with the molding surface 3A by the compressed air, and the resin sheet M is molded into a shape along the molding surface 3A. At this time, air existing between the molding surface 3A and the resin sheet M is discharged to the lower side of the mold 3 through the air passage 11. In other embodiments, the air present between the molding surface 3A and the resin sheet M may be actively discharged through the air passage 11 using a suction pump. When the compressed air is supplied, since the resin sheet M is sandwiched between the plug 8 and the molding surface 3A, the positional deviation of the resin sheet M in the horizontal direction is suppressed. Further, since the resin sheet M is disposed at a position close to the molding surface 3A by the plug 8, the amount of movement of the resin sheet M to the molding surface 3A is reduced, and the positional deviation of the resin sheet M is reduced.

According to the above embodiment, since the lower plate 6 supports the lower surface of the heated resin sheet M, sagging of the resin sheet M can be eliminated, and the state including the shape of the softened resin sheet M at the time of starting molding can be fixed. Further, since the positional deviation of the softened resin sheet M is reduced by the plug 8, the positional deviation of the resin sheet M with respect to the mold 3 can be reduced. This can reduce the deviation between the molding surface 3A of the mold 3 and the position of the pattern printed on the resin sheet M, and can accurately match the shape of the molded article with the position of the pattern.

Further, in the fourth step, after the resin sheet M is sandwiched between the plug 8 and the lower plate 6, the lower plate 6 and the plug 8 are lowered with respect to the holder 5 while sandwiching the resin sheet M. This can gradually widen the contact range around the first contact portion between the plug 8 and the resin sheet M, and reduce the positional displacement of the contact portion of the resin sheet M with respect to the plug 8. As a result, the positional displacement of the resin sheet M with respect to the mold 3 in the lateral direction can be reduced.

In the sixth step, the plug 8 is lowered with respect to the mold 3 to a position where the resin sheet M is sandwiched between the plug and the molding surface 3A. Therefore, since the resin sheet M is sandwiched between the plug 8 and the molding surface 3A, the positional deviation of the sandwiched portion of the resin sheet M can be suppressed. Further, since the resin sheet M can be disposed in the vicinity of the molding surface 3A before the compressed air is supplied, the amount of movement of the resin sheet M to the molding surface 3A when the compressed air is supplied can be reduced, and the positional deviation of the entire resin sheet M with respect to the molding surface 3A can be reduced. Since the plug 8 is configured to be temperature-adjustable, even if the resin sheet M comes into contact with the plug 8, a drop in temperature of the resin sheet M can be reduced. This can suppress molding defects of the resin sheet M caused by a temperature drop.

Further, when the resin sheet M is supported by the holder 5, the surface on which the pattern is printed is an upper surface, and thus, the ink contained in the pattern can be prevented from contacting the lower plate 6. This can suppress elution of ink or adhesion of the resin sheet M to the lower plate 6 due to dissolution of ink.

Next, a resin molding apparatus 50 according to a second embodiment will be described. As shown in fig. 11, the resin molding apparatus 50 of the second embodiment differs from the resin molding apparatus 1 of the first embodiment in the structure of the lower plate 6. The lower plate 6 of the resin molding apparatus 50 includes a heater 51 supported by the lower moving device 13 and a plate 52 in a flat plate shape supported to be movable in the vertical direction with respect to the heater 51. The heater 51 may be a heating element that generates heat by supplying electric current, or a heater that allows a high-temperature fluid such as superheated steam to pass through the inside. The plate 52 is heated by the heater 51.

The plate 52 has a flat upper surface and a plurality of guide pins 53 extending downward on a lower surface thereof. Each guide pin 53 enters a hole 54 which vertically penetrates the heater 51. A release prevention pin (not shown) for preventing the guide pins 53 from coming out of the holes 54 is provided at the tip (lower end) of each guide pin 53. A compression spring 56 is provided on the outer periphery of the guide pin 53 between the heater 51 and the plate 52, and the compression spring 56 biases the plate 52 upward relative to the heater 51. The compression spring 56 may be a coil spring or a leaf spring. In the initial state, the plate 52 is disposed at the position farthest upward from the heater 51 by the urging force of the compression spring 56.

In the resin molding apparatus 50 according to the second embodiment, in the fourth step of the above-described resin molding method, the controller 20 controls the elevation device 16 to lower the plug 8 with respect to the holder 5. Thereby, as shown in fig. 12, the plate 52 of the lower plate 6 descends together with the plug 8 against the urging force of the compression spring 56. This eliminates the need to lower the plate 52 in accordance with the lowering of the plug 8, and simplifies the lower moving device 13.

Next, a resin molding apparatus 60 according to a third embodiment will be described. As shown in fig. 13, the resin molding apparatus 60 of the third embodiment has a heating device 61 independent from the base 2 and a conveying device 62 that conveys the resin sheet M from the heating device 61 to the holder 5. The heating device 61 is disposed on the side of the compressed air tank 4 and the mold 3. The heating device 61 is preferably a device capable of uniformly heating the resin sheet M. The heating device 61 has a housing 65 defining a heating chamber 64. Heaters 66 are provided above and below the heating chamber 64, and the heaters 66 are heating elements that generate heat by receiving electric power, heaters that pass high-temperature fluid such as superheated steam, or the like, and the like.

The conveying device 62 may be, for example, a robot arm or a conveying roller. In the present embodiment, an example in which the conveyance device 62 is a robot is described. The conveying device 62 includes: an arm 67 having a joint, a support plate 68 provided at the tip of the arm 67, an actuator 71 that changes the relative position of each arm 67, and a control device 72 that controls the support plate 68 and the actuator 71. The controller 72 can numerically control the actuator 71 to move each of the arms 67 and the support plate 68 to an arbitrary position.

A plurality of suction passages (not shown) are formed in the lower surface of the support plate 68. Each suction passage is connected to a suction pump via a tube or the like. The support plate 68 is configured to be heatable. The support plate 68 may be formed of, for example, a metal plate that generates joule heat upon receiving the supply of electric power. The suction and heating effected by the support plate 68 is controlled by a control device 72.

Further, the conveying device 62 has a camera 73 that photographs the resin sheet M. The control device 72 detects a pattern printed on the resin sheet M or a position of the outer shape of the resin sheet M with respect to the support plate 68 from an image of the resin sheet M captured by the camera 73.

The resin sheet M is conveyed to the heating chamber 64 of the heating device 61 by a conveying roller, a robot, or the like, and is heated in the heating chamber 64. The resin sheet M heated by the heating device 61 is supported by the support plate 68 of the conveying device 62. The support plate 68 adsorbs the upper surface of the resin sheet M on the lower surface thereof by the negative pressure generated in each suction passage. At this time, in order to suppress a decrease in the temperature of the resin sheet M, the support plate 68 is preferably heated to the same extent as the temperature of the resin sheet M.

The control device 72 of the conveying device 62 detects the position of the pattern printed on the resin sheet M or the outer shape of the resin sheet M with respect to the support plate 68, based on the image of the resin sheet M captured by the camera 73. The control device 72 calculates a target position of the support plate 68 with respect to the holder 5 for disposing the resin sheet M at an appropriate position with respect to the holder 5, based on the pattern printed on the resin sheet M or the position of the outer shape of the resin sheet M with respect to the support plate 68. Then, the control device 72 drives the actuator 71 to move the support plate 68 to the target position, and transfers the resin sheet M to the lower member 5A of the holder 5. Thereafter, the conveying device 62 retreats the support plate 68 from the target position, and the holder 5 sandwiches the edge of the resin sheet M between the lower member 5A and the upper member 5B.

According to the above-described aspect, the upper heater 7 disposed between the compressed air tank 4 and the die 3 can be omitted, and the apparatus structure can be simplified. Further, the heating device 61 independent from the base 2 can be increased in size, and the resin sheet M can be uniformly heated. The conveying device 62 calculates the target position of the support plate 68 from the image of the resin sheet M captured by the camera 73, and transfers the resin sheet M to the holder 5, so that the resin sheet M can be arranged at an appropriate position of the holder 5. When the position of the resin sheet M is determined based on the pattern printed on the resin sheet M, the conveying device 62 fixes the position of the pattern in the molded product at an appropriate position even if the printing on the resin sheet M is shifted.

The above description has been made of the specific embodiments, but the present invention is not limited to the above embodiments and can be widely modified. In the above embodiment, the holder 5 is fixed to the base 2, and the die 3, the compressed air tank 4, and the lower plate 6 are configured to move up and down with respect to the base 2. However, the holder 5, the mold 3, the compressed air tank 4, and the lower plate 6 may be movable relative to each other in the vertical direction, and for example, the mold 3 may be fixed to the base 2, and the holder 5, the compressed air tank 4, and the lower plate 6 may be moved vertically relative to the base 2. The compressed air tank 4 or the lower plate 6 may be fixed to the base 2. The upper heater 7 is not necessarily required, and may be omitted.

In the above embodiment, the plug 8 has one lower end portion 8B, but in another embodiment, the plug 8 may have a plurality of lower end portions 8B. The shape of the plug 8 may be appropriately set to match the shape of the molding surface 3A.

The

resin molding apparatuses

1, 50, and 60 according to the present embodiment can be used to form a tailgate, a door including a sliding door, a front fender, a rear fender, a bumper panel, a front grille, a roof, and the like that constitute an automobile housing.

Claims

1. A resin molding apparatus, comprising:

a holder for supporting an edge of a resin sheet and horizontally arranging the resin sheet;

a mold provided below the holder so as to be movable relative to the holder in a vertical direction, the mold having an upward molding surface;

a compressed air tank provided above the holder so as to be movable relative to the holder in a vertical direction, the compressed air tank being capable of sandwiching the resin sheet between the compressed air tank and the mold;

a lower plate that is provided so as to be movable in the vertical direction and the horizontal direction with respect to the holder, supports the lower surface of the resin sheet, and heats the resin sheet;

a plug provided on a lower surface of the compressed air tank and pressing an upper surface of the resin sheet downward; and

a compressed air supply device which supplies compressed air to a lower surface of the compressed air tank to bring the resin sheet into close contact with the molding surface,

a protrusion for locking the resin sheet is provided at the lower end of the plug.

2. The resin molding apparatus according to claim 1,

the lower plate receives a supply of electric current to generate joule heat.

3. The resin molding apparatus according to claim 1,

the lower plate has a plate and a heater disposed below the plate.

4. The resin molding apparatus according to claim 3,

the plate is provided so as to be relatively movable in the up-down direction with respect to the heater, and a compression spring is provided between the plate and the heater.

5. The resin molding apparatus according to claim 1,

the resin molding apparatus has an upper heating device movable between a heating position above the resin sheet supported by the holder and a retracted position retracted from the heating position in a horizontal direction so that the plug can be lowered.

6. The resin molding apparatus according to claim 1,

the resin molding apparatus includes:

a heating device disposed on a side of the compressed air tank and the mold, for heating the resin sheet; and

and a conveying device that conveys the resin sheet heated by the heating device to the holder.

7. The resin molding apparatus according to any one of claims 1 to 6,

the plug is configured to be temperature adjustable.

8. The resin molding apparatus according to claim 1,

and printing a pattern on the surface of the resin sheet.

9. The resin molding apparatus according to claim 8,

the pattern is printed on the upper surface of the resin sheet.

10. A resin molding method for molding a resin molded product from a resin sheet, comprising:

a first step of supporting an edge of the resin sheet by a holder, supporting a lower surface of the resin sheet by a lower plate, and horizontally arranging the resin sheet above a mold having a molding surface facing upward;

a second step of heating the resin sheet by the lower plate;

a third step of bringing a lower end portion of a plug provided on a lower surface of a compressed air tank into contact with an upper surface of the resin sheet and sandwiching the resin sheet between the lower plate and the plug;

a fourth step of lowering the plug and the lower plate relative to the holder while maintaining the position of the holder, and bringing the resin sheet into close contact with the surface of the plug;

a fifth step of horizontally retracting the lower plate;

a sixth step of moving the compressed air tank and the mold relative to the holder in a vertical direction to sandwich the resin sheet between the compressed air tank and the mold; and

a seventh step of supplying compressed air to a lower surface of the compressed air tank to bring the resin sheet into close contact with the molding surface.

11. The resin molding method according to claim 10,

in the sixth step, the mold is configured to hold the resin sheet between the mold and the molding surface.

12. The resin molding method according to claim 10 or 11,

a protrusion is provided at a lower end of the plug, and the protrusion locks the resin sheet in the third step.

13. A resin molding apparatus, comprising:

after the plug is lowered relative to the holder to abut on the upper surface of the resin sheet, the lower plate is lowered relative to the holder while sandwiching the resin sheet between the lower plate and the plug in accordance with the lowering of the plug.

14. The resin molding apparatus according to claim 13,

the lower plate is retreated in the horizontal direction from below the resin sheet after being lowered by a prescribed distance.

15. The resin molding apparatus according to claim 14,

the plug is lowered relative to the mold to a position where the resin sheet is sandwiched between the plug and the molding surface.