JP2006175731A - Method and apparatus for molding dome-shaped molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for molding a dome-shaped molding which can perform pressure forming without generating deformation etc., by residual air between a dome-shaped molded recess and a transparent sheet. <P>SOLUTION: In a pressure forming mold 1, by forming a suction channel 4 for sucking air inside the dome-shaped molded recess 2, the transparent sheet 3 is expanded while air in the space between the inner peripheral surface of the recess 2 and the transparent sheet 3 is sucked from the channel 4 to decompress the space, so that the dome-shaped molding can be molded by pressure forming. In this way, the dome-shaped molding A can be pressure-formed without generating deformation etc., by confining air between the inner peripheral surface of the recess 2 and the transparent sheet 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a molding method and a molding apparatus for a transparent dome-shaped molded product used for a cover of an optical device or the like.

  A hemispherical transparent dome-shaped molded product is used as a cover that transmits light for optical equipment, such as a clear cover that covers a surveillance camera and a transparent glove of a lighting fixture. This transparent dome-shaped molded product is generally molded by injection molding, but if the thickness is 0.8 mm or less, for example, a thin thickness of about 0.2 to 0.5 mm, the molding die is used. Molding is difficult by injection molding due to the problem of resin filling properties.

  On the other hand, pressure forming is conventionally known as a method for forming a thin container having a small thickness (see, for example, Patent Document 1). Therefore, it has been studied to form a transparent dome-shaped molded product having a small thickness by this pressure forming.

FIG. 6 shows an example of forming a dome-shaped molded product A by pressure forming, and the pressure forming apparatus includes a pressure forming mold 1 formed by providing a dome-shaped forming recess 2 opened on the lower surface, and a heating plate 5. The heating die 6 is provided and formed. Then, first, the transparent sheet 3 formed of a thermoplastic resin is placed on the heating mold 6 and softened by heating the transparent sheet 3 with the heating panel 5, and the heating mold 6 as shown in FIG. The compressed air mold 1 is set on the top. At this time, a portion of the transparent sheet 3 placed on the heating die 6 and projecting outward from the heating plate 5 is airtightly sandwiched between the heating die 6 and the pressure forming die 1. Next, when air is supplied to the lower surface side of the transparent sheet 3 (illustration of air supply means is omitted), the transparent sheet 3 of the thermoplastic resin in the softened state becomes the dome-shaped concave portion 2 of the compressed air mold 1. The transparent sheet 3 swells in close contact with the inner peripheral surface of the dome-shaped recess 2 by the air pressure indicated by the arrow in FIG. 6B, and the dome corresponding to the shape of the dome-shaped recess 2 The shaped molded product A can be molded.
Japanese Patent Laid-Open No. 10-44581

  As described above, the pressure forming is performed by bringing the surface of the transparent sheet 3 opposite to the air supply surface into close contact with the inner peripheral surface of the dome-shaped forming recess 2 of the pressure forming mold 1. If air remains between the inner peripheral surface of the shaped concave portion 2 and the outer surface of the transparent sheet 3, the transparent sheet 3 cannot be brought into close contact with the inner peripheral surface of the dome shaped concave portion 2. In this case, the molded dome-shaped molded product A is deformed, and light transmission is distorted, which may cause blurring of an image particularly when used as a clear cover for covering a surveillance camera.

  However, when forming with a hemispherical deep drawing like the dome-shaped molded product A, it is difficult to smoothly remove air from between the inner peripheral surface of the dome-shaped molded recess 2 and the outer surface of the transparent sheet 3. Met.

  The present invention has been made in view of the above points, and a molding apparatus for a dome-shaped molded product capable of performing pressure-air molding without causing deformation due to residual air between the dome-shaped molded recess and the transparent sheet, and The object is to provide a molding method.

  The apparatus for producing a dome-shaped molded product according to the present invention arranges a transparent sheet 3 of a thermoplastic resin softened by heating at the opening of a dome-shaped molded recess 2 of a compressed air mold 1, and the dome-shaped transparent sheet 3 has a dome shape. A dome for forming a transparent dome-shaped molded product by supplying air to the surface opposite to the molding concave portion 2 and pressurizing it, and inflating the transparent sheet 3 so as to be in close contact with the inner peripheral surface of the dome-shaped molding concave portion 2. In the molding device for a shaped product, the compressed air molding die 1 is provided with a suction flow path 4 for sucking air inside the dome-shaped molding recess 2.

  According to the present invention, the air in the space between the inner peripheral surface of the dome-shaped concave portion 2 and the transparent sheet 3 is sucked from the suction flow path 4 and depressurized, and the transparent sheet 3 is expanded in this state. A dome-shaped molded product can be formed by pressure forming of the transparent sheet 3, and at this time, air can be prevented from remaining between the transparent sheet 3 and the inner peripheral surface of the dome-shaped molded recess 2. The dome-shaped molded product A can be pressure-molded without air being trapped between the inner peripheral surface of the molding recess 2 and the transparent sheet 3 to cause deformation or the like.

  An insertion member 10 is inserted into the suction channel 4 so that an end surface of the insertion member 10 is exposed to the suction port 9 which is an opening in the inner peripheral surface of the dome-shaped recess 2 in the suction channel 4. You may make it form the clearance gap 11 which can distribute | circulate air between the suction flow paths 4.

  In this way, the suction flow path 4 can open only the gap 11 on the inner peripheral surface of the dome-shaped concave portion 2, thereby facilitating the size of the opening on the inner peripheral surface of the dome-shaped concave portion 2. It is possible to adjust, and it is easy to form the opening of the suction channel 4 on the inner peripheral surface of the dome-shaped concave portion 2 without making a fine process for reducing the opening of the suction port 9 itself. In addition, it becomes easy to form the opening smaller, and the moldability can be improved by leaving no mark of the suction port 9 in the molded dome-shaped product A.

  Further, in the method for molding a dome-shaped molded product according to the present invention, a transparent sheet 3 made of a thermoplastic resin softened by heating is disposed in the opening of the dome-shaped molded concave portion 2 of the compressed air molding die 1. A transparent dome-shaped molded product is formed by supplying air to the surface opposite to the dome-shaped molded recess 2 and pressurizing it, and inflating the transparent sheet 3 so as to be in close contact with the inner peripheral surface of the dome-shaped molded recess 2. In the method for forming a dome-shaped molded product, the transparent sheet 3 is inflated in a state where the air in the space between the inner peripheral surface of the dome-shaped molded recess 2 and the transparent sheet 3 is sucked and decompressed. It is what.

  According to the present invention, when the transparent sheet 3 is inflated, it is possible to prevent the air from remaining between the transparent sheet 3 and the inner peripheral surface of the dome-shaped recessed portion 2. The dome-shaped molded product A can be pressure-air molded without trapping air between the peripheral surface and the transparent sheet 3 and causing deformation or the like.

  According to the present invention, the air between the inner peripheral surface of the dome-shaped concave portion and the transparent sheet is sucked and forcibly removed during the pressure forming, so that the inner peripheral surface of the dome-shaped concave portion and the transparent sheet A dome-shaped molded product can be pressure-formed without causing deformation or the like due to air trapped in between.

  Hereinafter, the best mode for carrying out the present invention will be described.

  1 and 2 show an example of an embodiment of the present invention, which is formed by providing a heating panel 5 on a part of the upper surface, and transparent of a thermoplastic resin disposed on the upper surface over the heating panel 5 and its periphery. A heating die 6 that heats and softens the sheet 3, and a dome-shaped concave portion 2 that opens at the lower surface is formed, and the surrounding portion of the transparent sheet 3 disposed on the upper surface of the heating die 6 is the heating die 6. Air is supplied to the surface opposite to the dome-shaped molding recess 2 of the transparent sheet 3 and the compressed air molding mold 1 disposed on the heating mold 6 so as to be airtightly sandwiched between the transparent sheet 3 and the dome-shaped transparent sheet 3. An air supply unit 7 is provided that is inflated so as to be in close contact with the inner peripheral surface of the molding recess 2 to form a compressed air molding apparatus.

  The compressed air molding die 1 is provided with a dome-shaped concave portion 2 so as to open on the lower surface thereof, and the inner peripheral surface of the dome-shaped concave portion 2 is formed as a hemispherical concave surface.

  The compressed air mold 1 is formed with a suction flow path 4 for sucking air inside the dome-shaped molding recess 2. One end of the suction channel 4 is opened by a suction port 9 provided on the inner peripheral surface of the dome-shaped recess 2, and the other end of the suction channel 4 is a suitable air suction device such as a suction pump outside the dome-shaped recess 2. (Not shown). The suction channel 4 is preferably provided at a plurality of locations on the inner peripheral surface of the dome-shaped recess 2. In the example shown in the drawing, six suction flow paths 4 are provided in the compressed air molding die 1, and at this time, three pieces are respectively provided at two positions facing each other in the vicinity of the opening of the inner peripheral surface of the dome-shaped molding recess 2. The suction ports 9 of the suction channel 4 are provided close to each other, and at each position, the suction ports 9 of the suction channel 4 are formed side by side in parallel to the opening surface of the dome-shaped molding recess 2. .

  In the illustrated example, one end of the suction channel 4 is opened as a suction port 9 in the inner peripheral surface of the dome-shaped molding recess 2 of the compressed air mold 1, and the other end is appropriately formed on the upper surface of the compressed air mold 1. Opened as a connection port connected to the air suction device, and inside the compressed air mold 1, the suction flow path 4 is bent into a substantially L shape in which the horizontal flow path 4 a and the vertical flow path 4 b are connected in series. It is formed as an open channel. At this time, the opening diameter of the suction port 9 is preferably 0.6 mm or less. Particularly in the example shown in FIG. The suction port 9 is formed by opening the small diameter portion 13 on the inner peripheral surface of the dome-shaped concave portion 2. Thus, by making the opening diameter of the suction port 9 small, it is possible to prevent the marks of the suction port 9 from remaining on the dome-shaped molded body after molding. The lower limit of the opening diameter of the suction port 9 at this time is not particularly limited, but when the suction port 9 is formed by mechanical processing, the practical lower limit is 0.1 mm due to processing limitations.

  Further, the insertion member 10 is inserted and disposed in the suction flow path 4, and the end surface of the insertion member 10 is exposed to the inner peripheral surface of the dome-shaped concave portion 2 through the suction port 9, and further, the insertion member 10 and the suction flow are A gap 11 through which air can flow is formed between the passage 4 and air inside the dome-shaped recess 2 may be sucked through the gap 11. In the example shown in FIG. 4, the insertion member 10 is inserted into the horizontal flow path 4 a of the suction flow path 4 formed in a substantially L shape by the horizontal flow path 4 a and the vertical flow path 4 b, and one of the insertion members 10 is arranged. The end surface is exposed to the inside of the dome-shaped molding recess 2 at the suction port 9 so that the end surface is flush with the inner peripheral surface of the dome-shaped molding recess 2.

  The insertion member 10 includes a shaft portion 10b having a smaller diameter than the inner diameter of the suction flow path 4 (the horizontal flow path 4a in the illustrated example) in which the insertion member 10 is disposed, and the suction port 9 side of the shaft portion 10b. A head portion 10a that is formed and has a diameter larger than that of the shaft portion 10b is provided, and the front end surface of the head portion 10a is exposed at the suction port 9.

  The insertion member 10 can be formed in an appropriate shape such as a columnar shape or a prismatic shape according to the shape or the like of the suction channel 4.

  The shaft portion 10b is formed to have a diameter slightly smaller than the inner diameter of the suction flow path 4 (lateral flow path 4a). For example, a part between the outer peripheral surface of the shaft section 10b and the inner peripheral surface of the suction flow path 4 Alternatively, a gap (relief gap 11a) communicating in the flow path direction of the suction flow path 4 is formed over the entire circumference.

  Further, the head 10 a has a gap forming portion 12 formed on the outer peripheral surface thereof, and the outer peripheral surface of the head 10 a and the inner periphery of the suction flow path 4 are formed at the portion where the gap forming portion 12 is formed. A gap (communication gap 11b) is formed between the surface and the inside of the dome-shaped recessed portion 2 and the relief gap 11a, and the outer periphery of the head 10a is formed in a portion where the gap forming portion 12 is not formed. The surface is formed so as to contact the inner peripheral surface of the suction channel 4. The gap forming portion 12 can be provided by forming the head portion 10 a so as to have a shape that is partially cut out from a shape that matches the inner peripheral surface of the suction flow path 4. At this time, the gap forming portions 12 can be provided at a plurality of locations on the head 10a, for example, at 2 to 6 locations. In the illustrated example, the tip of the head 10a is similarly formed in a circular cross section along the inner peripheral surface shape of the suction channel 4 formed in a circular cross section, and 4 on the outer periphery of the head 10a. The portion is formed so as to have a shape cut out in a plane parallel to a plane circumscribing the outer peripheral surface of the head 10 a, and the portion having the cut shape is formed as the gap forming portion 12. Further, the front end surface of the head 10 a is exposed to the inside of the dome-shaped recess 2 at the suction port 9 so as to be flush with the inner peripheral surface of the dome-shaped recess 2.

  By inserting and inserting such an insertion member 10 into the suction channel 4, the suction port 9 is largely blocked by the head 10a, and air constituted by the communication gap 11b and the escape gap 11a can flow. The gap 11 is opened between the gap forming portion 12 of the head portion 10a and the opening edge of the suction port 9, and the air inside the dome-shaped recess 2 can be sucked from the suction channel 4 through the gap 11. ing.

  The insertion member 10 is preferably fixed in the suction flow path 4 by an appropriate means. In the illustrated example, a screw hole 14 orthogonal to the suction flow path 4 is provided so as to open on the inner peripheral surface of the suction flow path 4, A set screw 15 is screwed into the screw hole 14, and the tip of the set screw 15 is brought into pressure contact with the outer peripheral surface of the shaft portion 10 b of the insert member 10 in the suction channel 4, thereby inserting the insertion member 10 into the suction channel 4. It is fixed to.

  When providing such an insertion member 10, the size and size of the insertion member 10 can be adjusted to easily adjust the size of the opening of the suction flow path 4 on the inner peripheral surface of the dome-shaped recess 2. Is possible. For this reason, even when the suction flow path 4 is formed with a relatively large diameter, it is fine to reduce the opening itself of the suction port 9 such as providing the small diameter portion 13 as shown in FIG. It becomes easy to make the opening of the suction channel 4 small without processing, and by forming the opening of the suction channel 4 in this way, the suction port 9 is formed in the dome-shaped molded body after molding. It is possible to prevent traces from remaining. Further, compared to the case where the opening of the suction port 9 is formed to have a small diameter, it is easy to form the opening of the suction channel 4 further smaller, and it is possible to form an opening of 0.1 mm or less. Further, it is possible to further prevent the trace of the suction port 9 from remaining on the molded dome-shaped molded body.

  The dimension of the gap 11 through which air can flow between the outer peripheral surface of the insertion member 10 and the inner peripheral surface of the flow passage is appropriately set. It is preferable to adjust so that the trace of the suction port 9 can be effectively prevented from remaining on the molded body A. In particular, in the insertion member 10 having the illustrated configuration, the clearance gap 11 a has a width in the range of 0.1 to 0.2 mm over the entire circumference between the outer peripheral surface of the shaft portion 10 b and the inner peripheral surface of the suction flow path 4. It is preferable to form. For the communication gap 11b, the maximum width between the gap forming portion 12 and the inner peripheral surface of the suction channel 4 and the opening edge of the suction port 9 is in a range of 0.01 to 0.2 mm. A gap 11 through which air can flow between the outer peripheral surface of the insertion member 10 and the inner peripheral surface of the flow passage is between the opening edge of the suction port 9 and the insertion member 10 on the inner peripheral surface of the dome-shaped molding recess 2. It is preferable to open with the dimension which becomes the range whose maximum width of 0.01-0.2 mm. In addition, the opening diameter of the suction port 9 at this time does not have to be formed as small as in the case shown in FIG. 3, and can be formed to an appropriate size without any particular limitation. Can be formed to the extent.

  Moreover, although the dimension of the communication gap 11b in the flow path direction, that is, the dimension of the head 10a in the flow path direction can be appropriately set, for example, this dimension can be formed to 5 mm.

  On the other hand, the heating die 6 is provided with a support base 17 in a circular air supply recess 16 provided at the center of the upper surface of the base body 15, and the air supply recess is supported on the support base 17. 16 is formed by disposing and providing a disk-shaped heating board 5. The heating platen 5 is arranged so that the upper surface is exposed on the upper surface of the central portion of the heating die 6, and the diameter of the heating platen 5 is slightly larger than the diameter of the circular opening on the lower surface of the dome-shaped recess 2. It is formed. A receiving frame 18 is provided on the periphery of the upper surface of the base body 15, and an elastic sheet 19 such as a ring-shaped silicon sheet is provided on the upper surface of the receiving frame 18. The receiving frame 18 is disposed so as to surround the outer periphery of the heating panel 5, and the upper surface of the heating panel 5 is slightly lower (about 3 mm) than the upper surface of the elastic sheet 19 of the receiving frame 18.

  A gap 11 is provided between the inner periphery of the air supply recess 16 and the support base 17 and the heating plate 5 to form an air supply path 20, and a gap is provided between the outer periphery of the heating plate 5 and the receiving frame 18. 11 and an air lead-out path 21 communicating with the air supply path 20 is formed. Further, the base plate 15 is provided with a pair of air introduction ports 22 at positions facing each other, and an air pipe 23 is connected to the air supply path 20 through the air introduction port 22. Both ends thereof are connected to each air inlet 22, and a compressor 25 is connected to the air pipe 23 via a switching valve 28 that is controlled so as to switch the air flow as will be described later. The air outlet path 21 is open to the upper surface of the heating die 6 over the entire circumference of the heating panel 5. The air supply means 7 is formed by the compressor 25, the air pipe 23, the air introduction port 22, the air supply path 20, and the air outlet path 21. 27 is a packing for keeping the air supply path 20 airtight. The air pipe 23 is provided with a switching valve 29 that is controlled so as to switch the air flow, as will be described later, and is connected to the outside via the switching valve 29.

  The heating plate 5 formed of a metal plate or the like is provided with a heater 10 (not shown in FIG. 1) on the lower surface side, and the heating plate 5 is formed so that the heating plate 5 generates heat. Further, an end heater 24 is provided over the entire periphery of the lower surface of the outer peripheral edge of the heating panel 5 so as to face the air supply path 20, and the outer periphery of the heating panel 5 is heated to generate heat from the heating panel 5. The variation in temperature is reduced. In addition, it is preferable that the outer surface including at least the upper surface of the heating panel 5 is painted black to generate far infrared rays. By generating far infrared rays in this way, it becomes easy to heat the transparent sheet 3 from the inside and uniformly heat it without heating unevenness.

  The heating die 6 is preferably provided with an air suction means 8 for sucking air between the heating plate 5 and the transparent sheet 3. Such an air suction means 8 can be composed of an air suction device such as a vacuum pump and a suction pipe that communicates the air suction device between the heating panel 5 and the transparent sheet 3. In the example shown in the drawing, a flow path constituted by an air supply path 20, an air introduction path 21, an air introduction port 22 and an air pipe 23 is also used as a suction pipe, and the air pipe constituting the suction flow path 4. The air suction means 8 is configured by connecting a vacuum pump 31 to a switch 23 via a switching valve 30 that is controlled to switch the air flow as will be described later. For example, the suction pipe may be configured by connecting the air pipe 23 and a separate pipe to the air supply path 20.

  In the step of heating the transparent sheet 3 of thermoplastic resin when performing molding using the pressure forming apparatus formed with the pressure forming mold 1 and the heating mold 6 as shown above, as shown in FIG. The heating mold 6 is moved to the side of the compressed air mold 1 (the suction flow path 4, the air supply means 7, and the air suction means 8 are not shown in FIG. 5). And the transparent sheet 3 of the thermoplastic resin formed with an acrylic thin plate etc. is mounted on the heating type | mold 6 like Fig.5 (a). As the transparent sheet 3, a thin sheet having a thickness of 0.8 mm or less, for example, about 0.2 to 0.5 mm is used. The transparent sheet 3 is formed such that the central portion to be molded is disposed on the heating plate 5 and the peripheral portion not to be molded is disposed on the elastic sheet 19 of the receiving frame 18, and the heating plate 5 is slightly lower than the elastic sheet 19. There is a slight gap 11 between the transparent sheet 3 and the upper surface of the heating panel 5. By placing the thermoplastic resin transparent sheet 3 on the heating mold 6 in this way, the portion to be molded of the transparent sheet 3 is heated by the heating platen 5 and becomes softened. At this time, heating is performed in a state where the transparent sheet 3 is covered with a heat insulating material 26 such as a heat resistant cloth so that the transparent sheet 3 is efficiently and uniformly heated by the heating platen 5. preferable.

  After heating the transparent sheet 3 of the thermoplastic resin in this way, the heat insulating material 26 is removed, and the heating die 6 is moved below the pressure forming die 1 as shown in FIG. The heating die 6 is moved to a position where the center of the heating plate 5 coincides with the center of the opening on the lower surface of the dome-shaped concave portion 2. Next, when the heating mold 6 is moved up (the pressure forming mold 1 may be moved down) and clamped, the elastic sheet 19 and the compressed air on the upper surface of the peripheral portion of the heating mold 6 are compressed as shown in FIG. A peripheral portion of the transparent sheet 3 that protrudes outward from the heating panel 5 is airtightly sandwiched between the lower surface of the peripheral edge of the opening of the dome-shaped molding recess 2 of the mold 1.

  Next, the air in the space surrounded by the inner peripheral surface of the dome-shaped recess 2 and the transparent sheet 3 is operated by operating a suction pump connected to the suction channel 4 via the suction channel 4. To depressurize the space. At this time, the pressure in the space is preferably in the range of 50 to 100 kPa. At the same time, the space between the inner peripheral surface of the dome-shaped concave portion 2 and the transparent sheet 3 is reduced by simultaneously sucking and reducing the pressure between the transparent sheet 3 and the heating panel 5 by the air suction means 8. The transparent sheet 3 may be prevented from expanding when the pressure is reduced. At this time, in the illustrated example, the switching valve 28 is controlled to block the flow of air between the compressor 25 and the air pipe 23 via the switching valve 28, and the flow of the air pipe 23 via the switching valve 28. , And the switching valve 30 is controlled to release all the air flow between the vacuum pump 31 and the air pipe 23 via the switching valve 30, and the vacuum pump 31 is operated in this state. The air is sucked through the air lead-out path 21, the air supply path 20, the air introduction paths 22, and the air pipes 23 around the outer periphery of the heating panel 5, and the pressure between the transparent sheet 3 and the heating panel 5 is reduced. Can do. At this time, it is preferable to reduce the pressure between the transparent sheet 3 and the heating panel 5 in the range of 50 to 100 kPa, and in particular, the same space as the space surrounded by the inner peripheral surface of the dome-shaped molding recess 2 and the transparent sheet 3. It is preferable to reduce the pressure to a pressure.

  Next, an appropriate time (for example, 1) is set in the space surrounded by the inner peripheral surface of the dome-shaped concave portion 2 and the transparent sheet 3 or between the transparent sheet 3 and the heating panel 5 by the above operation. After the pressure was reduced over about a minute), the suction of air through the suction channel 4 was continued to maintain the pressure-reduced state in the space surrounded by the inner peripheral surface of the dome-shaped recess 2 and the transparent sheet 3. In the state, the operation of the air suction means 8 is stopped and the air supply means 7 is operated. At this time, in the example shown in the figure, by controlling the switching valve 30, the flow of air between the air pipe 23 via the switching valve 30 and the vacuum pump 31 is closed and the air piping 23 via the switching valve 30 is closed. By releasing the air flow and controlling the switching valve 28, all the air flow between the air pipe 23 and the compressor 25 via the switching valve 28 is opened, and the compressor 25 is operated in this state. . In this way, air is supplied from the air pipe 23 through the two air inlets 22, and this air wraps around the entire circumference of the heating panel 5 through the air supply path 20, and the entire circumference of the outer circumference of the heating panel 5. It blows out from the air outlet path 21. The air supply pressure at this time is preferably set in the range of 1.5 to 5 MPa. The air blown out from the air lead-out path 21 enters the lower side of the transparent sheet 3 as indicated by an arrow in FIG. 1A from the gap 11 between the heating panel 5 and the transparent sheet 3, and is pressurized by air. Thus, the transparent sheet 3 heated and softened by the heating board 5 is expanded and expanded into the dome-shaped concave portion 2. Then, as shown in FIG. 1 (a), the transparent sheet 3 is pressed and brought into intimate contact with the inner peripheral surface of the dome-shaped recess 2 by a pressure applied by air, so that the transparent sheet 3 has the same inner peripheral shape as the dome-shaped recess 2 A transparent dome-shaped molded product A can be obtained by pressure forming into a dome shape.

  Here, since the end heater 24 is provided on the lower surface of the outer peripheral edge of the heating panel 5 so as to face the air supply path 20 as described above, the air in the air supply path 20 is supplied to the end heater 24. The transparent sheet 3 can be expanded by air heated in this way and can be compressed and formed by pressure, and the transparent sheet 3 can be prevented from being cooled by this air.

  In this way, after the transparent sheet 3 is expanded and compressed by air pressure over an appropriate time (for example, about 1 minute), the switching valve 29 is controlled to one air inlet 22 through the switching valve 29. (The air introduction port 22 on the opposite side of the switching valve 29 from the compressor 25 side) is opened to the outside and the air flow between the other air introduction port 22 via the switching valve 29 and the outside. The flow of air and the flow of air in the air flow path 23 via the switching valve 29 are closed, and the switching valve 28 is controlled to connect the compressor 25 and the one air introduction port 22 via the switching valve 28. The air flow and the air flow in the air flow path 23 via the switching valve 28 are closed, and the air flow between the compressor 25 and the other air inlet 22 via the switching valve 28 is opened. With the function of the switching valves 28 and 29 provided in the air pipe 23, the air in the air supply path 20 is exhausted from one air introduction port 22 and the air is supplied from the other air introduction port 22 to the air supply path 20. Since the supplied air is hardly heated by the end heater 24, the formed dome-shaped molded product A is cooled by this unheated cold air. be able to. After cooling the dome-shaped molded product A in this way, the heating die 6 is moved downward (the pressure forming die 1 may be moved upward), and the die is opened. Further, the heating die 6 is moved to the side of the pressure forming die 1. The dome-shaped molded product A can be taken out after being moved in the direction.

  When the dome-shaped molded product A is molded in this way, when the softened transparent sheet 3 is expanded and expanded into the dome-shaped molded recess 2 by the air supply means 7, the inner peripheral surface of the dome-shaped molded recess 2 Since the space between the transparent sheet 3 is depressurized, the remaining of the air between the expanded transparent sheet 3 and the inner peripheral surface of the dome-shaped molding recess 2 is prevented, and the dome-shaped molded article A to be molded is molded. In addition, it is possible to prevent molding defects such as irregularities due to the remaining air.

  Further, by adjusting the opening diameter of the suction port 9 or by arranging the insertion member 10 in the suction flow path 4, by adjusting the size of the gap 11 between the insertion member 10 and the suction port 9, The moldability can be further improved by leaving no trace of the suction port 9 in the molded dome-shaped product A. In particular, the opening diameter of the suction port 9 is 0.6 mm or less as described above. Alternatively, if the maximum width between the gap forming portion 12 of the insertion member 10 and the opening edge of the suction port 9 is in the range of 0.01 to 0.2 mm, molding defects due to the trace of the suction port 9 remaining. Can be further suppressed.

It is sectional drawing which shows embodiment of this invention. It is a top view which shows embodiment same as the above. It is a partial cross section figure which shows an example of a structure of the suction flow path in embodiment same as the above. (A) is a partial cross-sectional view showing another example of the configuration of the suction channel in the embodiment described above, and (b) is a front view of the suction port in (a). The process of pressure forming is shown, and (a) to (c) are schematic sectional views. A conventional example is shown, and (a) and (b) are sectional views.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure molding die 2 Dome shape recessed part 3 Thermoplastic resin transparent sheet 4 Suction flow path 9 Suction port 10 Insertion member 11 Crevice

Claims (3)

  A transparent sheet of thermoplastic resin softened by heating is placed in the opening of the dome-shaped molding recess of the pressure forming mold, and air is supplied to the surface opposite to the dome-shaped molding recess of the transparent sheet to pressurize and transparent In a dome-shaped molded product molding apparatus for molding a transparent dome-shaped molded product by inflating the sheet so as to be in close contact with the inner peripheral surface of the dome-shaped molded concave portion, the compressed air mold is provided with the dome-shaped molded concave portion. An apparatus for forming a dome-shaped molded product, comprising a suction channel for sucking air inside.   An insertion member is inserted and disposed in the suction channel such that an end surface of the insertion member is exposed to a suction port that is an opening in the inner peripheral surface of the dome-shaped concave portion in the suction channel, and between the insertion member and the suction channel. The dome-shaped molded product forming apparatus according to claim 1, wherein a gap through which air can flow is formed.   A transparent sheet of thermoplastic resin softened by heating is placed in the opening of the dome-shaped molding recess of the pressure forming mold, and air is supplied to the surface opposite to the dome-shaped molding recess of the transparent sheet to pressurize and transparent In a method for forming a dome-shaped molded product, in which a sheet is inflated so as to be in close contact with the inner peripheral surface of the dome-shaped molded recess, the inner peripheral surface of the dome-shaped molded recess and the transparent A method for forming a dome-shaped molded article, wherein the transparent sheet is expanded in a state where the air in the space between the sheets is sucked and decompressed.

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