JP4174840B2 - Skin shaping method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of shaping a skin used for a molded product such as a door trim of an automobile into a predetermined shape, and more specifically, shaping a skin formed from a woven fabric or a nonwoven fabric into a three-dimensional shape without deformation such as a pattern. On how to do.
[0002]
[Prior art]
For example, some automobile door trims, as shown in FIG. 7, for example, have an outer skin formed from a woven fabric or a non-woven fabric partially disposed in a resin molded body. Thus, by using a skin formed from a woven fabric or a nonwoven fabric, the tactile sensation is improved as compared to a resin skin, and a high designability can be imparted by using a skin having various patterns.
[0003]
By the way, since the surface of a door trim or the like is generally a complicated uneven shape, the shape of the skin often has a complicated three-dimensional shape. The following two methods are known as methods for integrating such a complex three-dimensional skin with the surrounding resin molding.
First, there is a wood grain adhesion method as a first method. This method is a method in which the peripheral edge portion of the skin is pressed into a groove formed in the resin molded body and bonded and integrated. Specifically, the skin is first cut into a substantially two-dimensional developed shape of a three-dimensional shape for the purpose. On the other hand, for example, a door trim-shaped resin molded body is formed by injection molding or the like. In the resin molded body, a groove is formed in a portion that becomes a boundary with the skin. And an adhesive agent is apply | coated to a resin molding or an outer skin, and the outer periphery and the resin molding are integrally joined by pushing the peripheral part of an outer skin into a groove | channel, and adhere | attaching.
[0004]
There is also known an in-mold molding method in which a resin molded body is molded in a state in which a skin is disposed in a mold, and the resin molded body and the skin are integrated. In this method, it is necessary to control the resin from leaking to the surface of the skin, and in the skin formed from a woven fabric or nonwoven fabric, a skin layer in which a barrier layer made of a thermoplastic resin sheet such as polypropylene is formed on the back side thereof Is used. Then, the skin body is shaped in advance into a predetermined shape by vacuum forming, and is placed in a mold, and a resin molded body is formed by injection molding or the like. As a result, the barrier layer and the resin molded body are joined, and a resin molded body having a skin partly formed from a woven fabric or a nonwoven fabric is produced.
[0005]
[Problems to be solved by the invention]
However, in the grain-in-bonding method, there is a problem that the number of man-hours for applying and drying the adhesive and for pressing the peripheral edge of the skin into the groove of the resin molded body are great. Further, in the step of pushing the outer periphery of the skin into the groove, wrinkles may occur in the skin, and there is a problem that the defect rate is high. Furthermore, there is also a problem that adhesion peeling between the resin molded body and the skin tends to occur.
[0006]
In addition, the in-mold molding method requires less man-hours, but it is necessary to shape the skin body into a predetermined shape by vacuum molding. However, in vacuum forming, the rate of elongation of the skin varies partially depending on the uneven shape of the mold, and a portion that hardly extends and a portion that extends by about 30% are mixed. Therefore, when a skin having a pattern is used, there is a problem that the design is partially deformed and the design property is lowered.
[0007]
Furthermore, in vacuum forming, in order to perform molding while holding the peripheral edge of the skin, a step of cutting the peripheral edge after molding is required, and there is a problem that the yield of the skin is low and the man-hour is increased.
The present invention has been made in view of such circumstances, and an object of the present invention is to shape the skin so that the yield is high and in-mold molding is possible without impairing the design.
[0008]
[Means for Solving the Problems]
The skin shaping method of the present invention that solves the above problems is characterized by cutting a skin body including a sheet layer made of a thermoplastic resin and a fibrous skin layer laminated on the surface of the sheet layer. A cutting process to develop a developed skin having a substantially two-dimensional developed shape of a three-dimensional shape;
Using an opening and a holding plate having a plurality of chucks around the opening, and placing the developed epidermis in the opening by gripping with the chuck;
It has a projecting member that can be moved in and out of the mold surface of the shaped lower mold and the shaped upper mold and the shaped lower mold, and the tip surface is located at the same position as the highest surface of the mold surface when it protrudes to the maximum from the mold surface. Using a press die
At least the sheet layer of the developed epidermis is heated and softened and placed in the press die, and when the developed epidermis comes into contact with the tip surface of the projecting member that is projected to the maximum, the gripping by the chuck is released and the projecting Molding process for holding the developed skin body between the mold surface of the shaping upper mold facing the member and press-molding the peripheral edge of the developed skin body in a free state to form the developed skin body in a three-dimensional shape It is to become more.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The skin body referred to in the present invention has at least a sheet layer made of a thermoplastic resin. For example, a two-layered skin consisting of a skin layer such as woven fabric and a sheet layer made of polypropylene or the like laminated on the back surface of the skin layer, or a skin layer such as woven fabric and polypropylene laminated on the back surface of the skin layer, etc. And a three-layered skin body composed of an elastic layer such as urethane foam or PP foam laminated on the back surface of the sheet layer.
[0010]
As the thermoplastic resin sheet layer, various thermoplastic resins such as polypropylene, polyethylene, hard polyvinyl chloride, acrylic resin, and polyamide can be used as long as they can be shaped into a predetermined shape by press molding in the molding process described later. Can do.
As the skin layer, a fibrous material such as a woven fabric, a nonwoven fabric or a knitted fabric can be used.
[0011]
In the shaping method of the present invention, first, in the cutting step, a developed skin having a substantially two-dimensional developed shape of a target three-dimensional shape is formed from the sheet-like skin. This cutting step can be performed by punching, cutting, or the like. The developed epidermis has a substantially two-dimensional developed shape of the target three-dimensional shape, and may be a substantially two-dimensional developed shape having a gripping margin used in the molding process described later, or an accurate two-dimensional shape having no gripping at all. It can also be set as a developed shape. Also, as in the case of conventional vacuum forming, a holding margin may be provided at the peripheral portion. However, as the size of the holding margin or the grip margin increases, the yield of the epidermis decreases, so there is no accuracy to grasp at all. It is particularly desirable to have a two-dimensional developed shape.
[0012]
In the molding step, at least the sheet layer of the developed skin is heated and softened, and is placed in a press mold and press-molded in a state where the movement of at least the peripheral edge of the developed skin is free. Is done. Since the development skin is press-molded with at least the peripheral edge moving freely, even if the development skin is deformed by the stress acting during the press molding, there is almost no elongation on the surface of the development skin. Therefore, since it does not stretch greatly locally, the pattern on the surface of the skin after shaping is not deformed, and the skin has a constant pattern regardless of the shape irregularities.
[0013]
In order to heat at least the sheet layer, it can be performed in the same manner as a normal press molding method such as hot air or hot plate. Although the sheet layer may be heated and softened by heating the entire developed epidermis, it is desirable to devise so that the sheet layer is preferentially heated in terms of thermal efficiency .
[0014]
If a grip margin is formed on at least a part of the peripheral portion of the developed skin body, the positioning with respect to the press die is facilitated by holding the grip margin. However, since the yield of the epidermis corresponding to the area of the grip is reduced, it is preferable to hold the main body of the developed epidermis as described above.
The shaped skin formed into a predetermined shape in the molding process is integrated with the resin molded body by in-mold molding, in which the molded skin is placed in the mold and molded into a resin molded body. It is formed. In this in-mold molding, a known molding method such as injection molding, transfer molding or compression molding can be used. In some cases, the shaped skin may be integrated with a separately formed resin molding by bonding or the like.
[0015]
【Example】
Hereinafter, the present invention will be described specifically by way of examples. In this embodiment, the three-dimensional shaped skin 13 constituting a part of the door trim of the automobile shown in FIG. 7 is formed, and then the entire door trim is manufactured by in-mold molding.
FIG. 1 shows a schematic configuration diagram of the shaping apparatus used in the present embodiment. This shaping apparatus forms a three-dimensional shaped shaping skin 13 from the skin body 1 shown in FIG. 2, and comprises a skin feeding device 2, a punching device 3, a conveying device 4, and a pressing device 5. Has been.
[0016]
As shown in FIG. 2, the skin body 1 includes a polypropylene sheet layer 10 and a skin layer 11 made of a woven fabric laminated on the surface of the sheet layer 10.
The skin supply device 2 has a box-like placement unit 20 in which a plurality of skin bodies 1 cut into a rectangular shape are stacked so that the skin layer 11 is on the upper side, and placed on the placement unit 20. The uppermost epidermis body 1 is sucked and transported to the punching device 3. A pressing device 22 is provided in the mounting portion 20 to press the stacked skin body 1 upward, so that the top of the stacked skin body 1 is positioned at the top of the mounting portion 20. In addition, each time the transport unit 21 transports one epidermis 1, the laminated epidermis 1 moves upward by one thickness of the epidermis 1.
[0017]
The transport unit 21 attracts one epidermis 1 by negative pressure and lifts it from the mounting unit 20, and transports the epidermis 1 to the punching device 3 by driving a cylinder device (not shown).
The punching device 3 includes a punching cylinder 30 driven in the vertical direction, a cylindrical punching upper die 31 held at a driving end of the punching cylinder 30, a base 32 disposed below the punching cylinder 30, a base A punching lower die 33 fixed to the base 32 is formed. A pressing member 34 is provided on the inner peripheral portion of the punching upper die 31 so as to be movable relative to the punching upper die 31 in the vertical direction. A frame-shaped receiving member 35 is provided on the outer peripheral portion of the punched lower die 33 so as to be movable relative to the punched lower die 33 in the vertical direction. The developed skin 12 punched by the punched upper die 31 and the punched lower die 33 is configured to have a two-dimensional developed shape of the intended three-dimensional shaped skin 13.
[0018]
First, in a state where the upper surface of the punching lower mold 33 and the upper surface of the receiving member 35 are in the same plane, the outer skin 1 is transferred by the transfer portion 21 and placed on the punching lower mold 33 and the receiving member 35. The Next, the punching upper die 31 is lowered together with the presser member 34, and the presser member 34 is brought into contact with the skin body 1 to sandwich the skin body 1 together with the punching lower die 33. Thereafter, when the punching upper die 31 is further lowered, the receiving member 35 is pressed and lowered by the punching upper die 31, and the holding member 34, the sandwiched portion of the skin body 1 and the punching lower die 33 are relatively raised and punched. Enters mold 31. Therefore, a shearing force acts between the upper punch 31 and the lower punch 33 on the outer skin 1, and the outer skin 1 is punched into a predetermined shape determined by the shapes of the upper punch 31 and the lower punch 33.
[0019]
When the upper die 31 is lifted after punching, the developed skin 12 punched into a predetermined shape determined by the shapes of the upper die 31 and the lower die 33 remains and remains on the surface of the lower die 33. The remaining part of the body 1 remains on the surface of the receiving member 35 located below the front end surface of the punched lower die 33.
The conveying device 4 includes a pair of cylinder devices 40, 40 ′ fixed to the base 32 and a pair of guides fixed to the drive ends of the pair of cylinder devices 40, 40 ′ and extending in parallel to the punching device 3 side. A pair of holding plates 42, 42 ′ slidably held by the pair of guide plates 41, 41 ′ and the pair of holding plates 42, 42 ′ along the guide plates 41, 41 ′. And a drive source (not shown) that slides in synchronization with each other. That is, the pair of holding plates 42 and 42 'can move between the punching device 3 and the press device 5 by sliding along the guide plates 41 and 41', and drive the cylinder devices 40 and 40 '. By this, it is possible to move in a direction close to and away from each other.
[0020]
Further, when the pair of holding plates 42, 42 ′ are close to each other, an opening 43 that is slightly larger than the outer peripheral shape of the developed skin 12 is formed between the pair of holding plates 42, 42 ′. Yes. A plurality of chucks 44 that protrude centripetally toward the opening 43 are fixed to the pair of holding plates 42 and 42 '.
Before the punching device 3 completes the punching of the skin 1, the pair of holding plates 42 and 42 ′ move to the position of the punching lower die 33 and stand by. When the punching upper die 31 is lifted after the punching is completed, the pair of guide plates 41 and 41 ′ are driven in the directions close to each other by the cylinder devices 40 and 40 ′, and an opening is formed between the pair of holding plates 42 and 42 ′. 43 is formed, and the developed epidermis 12 is disposed in the opening 43. The peripheral portion of the developed skin 12 is gripped by the plurality of chucks 44.
[0021]
The pair of holding plates 42 and 42 ′ holding the developed skin 12 in the opening 43 is conveyed to the press device 5 by a driving source (not shown). The pressing device 5 is formed on a first cylinder 50 that is held on a base 32 and driven in the front-rear direction and the up-down direction, and is formed on a shaping surface that is held on the driving end of the first cylinder 50 and has a predetermined three-dimensional shape. The mold 51 includes a second cylinder 52 disposed below the first cylinder 50, and a shaped lower mold 53 that is fixed to the driving end of the second cylinder 52 and driven in the vertical direction.
[0022]
Further, in the pressing device 5, a heater 54 is arranged so as to be movable in the front-rear direction (horizontal direction perpendicular to the direction in which the pair of guide plates 41, 41 ′ extends) by a drive source (not shown), and is conveyed when moved forward. It is configured to be positioned below the pair of holding plates 42, 42 ′.
When the pair of holding plates 42 and 42 ′ holding the developed skin 12 is conveyed to the press device 5, the heater 54 moves forward and is positioned directly below the developed skin 12. As a result, the sheet layer 10 is heated and softened. Then, the heater 54 moves backward, and the shaping upper die 51 and the shaping lower die 53 come close to each other by driving the first cylinder 50 and the second cylinder 52.
[0023]
As shown in FIG. 3, the shaped lower mold 53 is provided with a plurality of projecting members 55 that can be moved in and out of the mold surface, and the plurality of projecting members 55 are respectively formed on the mold surface by springs 56 embedded in the shaped lower mold 53. It is urged in the direction protruding from. When the projecting member 55 protrudes to the maximum from the mold surface, each tip surface is configured to be at substantially the same position as the highest surface of the mold surface of the shaped lower mold 53.
[0024]
In this embodiment, the shaped lower mold 53 is configured to first contact the developed skin 12. Accordingly, the front end surfaces of the plurality of projecting members 55 first come into contact with the developed skin 12, but at that time, the gripping by the chuck 44 is released, and the pair of holding plates 42 and 42 'are driven in a direction away from each other. As a result, the developed skin 12 is in a free state without restraint, but is supported by the plurality of projecting members 55 as shown in FIG. 3, so that the same state as if gripped by the chuck 44 without fluctuation in position. It will be held at.
[0025]
Then, due to further proximity between the shaping upper mold 51 and the shaping lower mold 53, the mold surface of the shaping upper mold 51 also comes into contact with the developed skin 12, and the developed skin 12 is pressed. The pressing force is transmitted to the projecting member 55 through the developed skin 12, and the projecting member 55 is pressed against the urging force of the spring 56 to be immersed in the shaped lower mold 53. Therefore, the developed skin 12 is deformed as shown in FIG. 5 after the state of FIG. 4, and the shaped skin 13 is formed by cooling and solidifying the sheet layer 10.
[0026]
That is, even if the pressing force by the shaping upper mold 51 and the shaping lower mold 53 acts on the developed skin 12, the shaped skin 12 is not restrained and the peripheral edge is in a free state. The body 12 does not stretch unevenly. Therefore, since it does not stretch locally, regardless of the uneven shape, the resulting shaped skin 13 has a uniform pattern and exhibits a high design.
[0027]
The obtained shaped skin 13 is arranged on the mold surface of the injection mold 6 as shown in FIG. 6, and a resin molded body 14 is formed by injection molding as shown in FIG. The surface of the sheet layer 10 of the shaped skin 13 is melted by the heat of the molten resin at the time of molding, and a door trim in which the shaped skin 13 is welded integrally with the resin molded body 14 is manufactured.
[0028]
【The invention's effect】
That is, according to the skin shaping method of the present invention, even if a skin having a pattern is used, the pattern is not partially deformed, and the design property is prevented from being lowered. Further, the yield of the skin is remarkably improved as compared with the vacuum forming method and the like, and the in-mold forming is possible, so that the man-hours can be greatly reduced as compared with the graining adhesion method.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view of a main part of an epidermis used in one embodiment of the present invention.
FIG. 2 is an explanatory perspective view showing a configuration of a shaping apparatus used in one embodiment of the present invention.
FIG. 3 is a cross-sectional view of the main part of the press die at the initial stage of the molding process in one embodiment of the present invention.
FIG. 4 is a cross-sectional view of the main part of the press die in the middle of the molding process in one embodiment of the present invention.
FIG. 5 is a cross-sectional view of the main part of the press die at the end of the molding process in one embodiment of the present invention.
FIG. 6 is a cross-sectional view of an essential part of an in-mold mold having the shaped skin obtained in one embodiment of the present invention.
FIG. 7 is a cross-sectional view of an essential part of a door trim having a shaped skin obtained in one embodiment of the present invention.
[Explanation of symbols]
1: epidermis 2: epidermis supply device 3: punching device 4: transport device 5: press device 12: developed epidermis
13: Shaped skin 31: Punched upper die 43: Opening
44: Chuck 51: Upper mold 53: Lower mold

Claims (1)

A skin layer including a sheet layer made of a thermoplastic resin and a fibrous skin layer laminated on the surface of the sheet layer is cut to obtain a developed skin body having a substantially two-dimensional developed shape of a target three-dimensional shape. Cutting process;
Using the opening and a holding plate having a plurality of chucks around the opening, and placing the developed epidermis in the opening by gripping with the chuck; and
Protruding member that can be freely inserted and removed from the mold surface of the shaped lower mold and the shaped upper mold and the shaped lower mold, and whose tip surface is substantially at the same position as the highest surface of the mold surface when projecting from the mold surface to the maximum Using a press mold with
When at least the sheet layer of the developed skin is heated and softened and placed in the press mold, the developed skin is brought into contact with the tip surface of the projecting member that is projected to the maximum by the chuck. Holding the developed skin body between the mold surface of the shaping upper mold facing the projecting member after releasing the gripping , press forming the peripheral edge of the developed skin body freely A method for shaping a skin, comprising: a forming step of forming a developed skin body into the three-dimensional shape.

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