JP2006192797A - Vacuum forming method and vacuum forming mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum forming method which can mold a skin material in the shape of deep drawing by suppressing a decrease in the thickness of the skin material and improving the adhesion of the skin material to a substrate, and to provide a vacuum-forming mold. <P>SOLUTION: A female mold 20 has a mold surface, and a recess part 21 is formed in the mold surface. A projection part 31 is formed in a male mold 30 and inserted into the recess part 21 by mold clamping. A cutting blade 34 is fitted to the projected surface 31a of the projection part 31. A substrate 44 is mounted on the mold surface of the female mold 20, and a skin material 43 is arranged between the female mold 20 and the male mold 30. When the distance between the female mold 20 and the male mold 30 is narrowed, a cutting end 43a is formed in the skin material 43 by the cutting blade 34. The male mold 30 is made to approach the female mold 20, and the end parts 43b and 43c of the skin material 43 on the periphery of the cutting end 43a are expanded and inserted into the recess part 21 to clamp the mold. The skin material 43 is sucked through the vacuum suction hole of the female mold 20 to be closely adhered to the substrate 44 to mold the skin material 43. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vacuum forming method and a vacuum forming die that can vacuum-form a skin material and simultaneously adhere the skin material to a substrate.

As interior parts of automobiles, there are molded products such as an instrument panel 50 and a door trim shown in FIG. These molded products are produced by, for example, the following vacuum forming method. First, a base material to be an insert is placed on a female mold surface. In parallel with this, a skin material lined with a foam layer is disposed between the female mold and the male mold. At this time, the skin material is heated and softened. Next, while closing the mold, the skin material is formed by suction through a vacuum suction hole provided in the female mold surface, and is integrated with the base material.
Moreover, in these molded articles, a deep dent may be provided, for example like the meter hood part 51 of the instrument panel 50 shown in FIG.

  By the way, as a vacuum forming method, in the cited document 1, a cut groove portion is provided in a lower mold corresponding to an elevating type cutting blade, and the skin is adjusted deeply along the outer periphery of the cut groove portion. Disclosure of the technology to prevent the skin from slipping when cutting with the cutting blade, by providing appropriate unevenness to the skin in the groove for cutting by providing an uneven portion to ensure sufficient biting amount of the cutting blade Has been.

  In Cited Document 2, the process of vacuum forming the skin and the core with the cushion layer by using a dummy core when the skin is pasted on the surface of the core material with the cushion layer and forming the laminated molded body. A technique for continuously performing a process of adhering an epidermis to a material is disclosed.

JP 2002-225124 A JP 2004-050423 A

However, in so-called deep drawing molding in which a flat thermoplastic material is molded with a mold to provide a deep recess in the molded product, there are the following problems.
FIG. 6 is a cross-sectional view showing a mold closing process when the instrument panel 50 is molded. This cross section is a cross section of the meter hood portion 51 of the instrument panel 50 and corresponds to a cross section taken along the line AA of FIG. 5, and the meter hood portion 51 is a deep depression.
As shown in FIG. 6, the female mold 60 has a recess 61. The recessed portion 61 is surrounded by a first convex portion 62 having a triangular cross section on one side of the concave portion 61, a second convex portion 63 having a rectangular section on the other side, and a bottom surface 61a therebetween, as a deep recess. Is formed.
When the base material 44 serving as an insert is placed on the mold surface of the female mold 60 having the recessed portion 61, and the skin material 43 is formed by placing the skin material 43 between the female mold 60 and the male mold 70. The ridge line 62b and the second convex portion of the first convex portion 62 along the side surface 62a on the concave portion side of the first convex portion 62, the bottom surface 61a of the concave portion 61, and the side surface 63a on the concave portion side of the second convex portion 63. Since the distance between the edge 63 b of 63 and the edge 63 b of the first protrusion 62 is longer than the linear distance between the edge 63 b of the second protrusion 63, the skin material 43 extends. From the limit of the elongation rate of the skin material 43, as shown in FIG. 6, the side surface 62 a on the concave portion side of the first convex portion 62 and the concave portion 61 side of the second convex portion 63 are sandwiched across the base material 44. A tear occurs in each part of the skin material 43 facing the side surface 63a. Thus, when a molding defect occurs during molding, there is a problem that the quality in appearance deteriorates.

Even if the molding can be performed without any trouble in appearance, the following problems arise.
FIG. 7A is a cross-sectional view showing a mold closing process when the instrument panel 50 is molded, and FIG. 7B is a cross-sectional view of the instrument panel 50 when the mold is removed. FIG. 7A corresponds to a diagram showing a mold closing process of a portion B in FIG. 7B.
Even when the skin material 43 can be formed into a deep-drawn shape, a gap is formed between the skin material 43 and the base material 44 due to the thin skin material 43 as shown in FIG. Arise. Thereby, even if a pressing pressure is applied to the male mold 70, the pressing pressure is not transmitted from the skin material 43 to the base material 44, so that the skin material 43 does not adhere to the base material 44. As described above, there is a problem that the adhesion of the skin material 43 to the base material 44 is poor even if there is no molding defect in appearance. At this time, in order to adhere the skin material 43 and the base material 44, even when the mold is closed by applying a predetermined adhesive to the base material 44, the adhesiveness of the skin material 43 to the base material 44. Will not improve.
Further, since the mold is closed and returned to room temperature, the shrinkage of the skin material 43 causes a shrinkage force to act on the skin material 43 in the direction of the arrow as shown in FIG. It is also conceivable that the is peeled off from the substrate 44.

  Accordingly, in view of the above problems, the present invention provides a vacuum forming method capable of forming a skin material into a deep-drawn shape by suppressing a reduction in the thickness of the skin material and improving the adhesion of the skin material to the base material. And it aims at providing a vacuum forming die.

In order to achieve the above object, the vacuum forming method of the present invention includes a first mold in which a recessed portion is formed, a protruding portion to be inserted into the recessed portion, and a cutting blade on the protruding surface of the protruding portion. By using a vacuum forming mold comprising the second mold provided, placing the skin material between the first mold and the second mold, closing the mold, and vacuuming the mold, A vacuum forming method in which a skin material is brought into close contact with a base material placed on a mold of 1 to produce a draw-formed product having a dent, and the interval between the first mold and the second mold is narrowed with a cutting blade. A step of forming a cut surface in the skin material, and a step of moving the second mold toward the first mold side and the protrusion pressing the end of the skin material around the cut surface against the base material. And
With this configuration, when the distance between the first mold and the second mold is narrowed, first, the cutting blade comes into contact with the skin material. Then, by further narrowing this interval, a cut edge is formed in the skin material with the cutting blade, the end of the skin material around the cut edge enters the recess at the outer periphery of the protrusion, and the protrusion is based on this end. It presses on the site | part facing the bottom part of the dent part among materials. Accordingly, the depression can be formed while preventing the skin material from being thinned. Therefore, first, the skin material can be molded without being broken. Second, there is no gap between the base material and the skin material. Therefore, it becomes possible to adhere the skin material to the base material. Furthermore, the adhesiveness to the base material of a skin material can be improved by apply | coating an adhesive agent to a base material beforehand, performing mold closing, and pressing a 2nd type | mold.

Preferably, the base material has a concave portion corresponding to the depression of the drawn product, and an opening into which the cutting blade is inserted is formed at the bottom of the concave portion. With this configuration, by forming a recess in the base material and opening the bottom, it is possible to produce a drawing material having an opening at the bottom of the recess at the same time as forming the skin material with a vacuum forming die, A step of providing an opening after molding can be omitted.
Preferably, the step of forming the cut end and the step of pressing the end are performed by vacuum suction in the mold through a vacuum suction hole provided in the first mold. With this configuration, the end portion of the skin material around the cut end is sufficiently inserted into the recessed portion by vacuum suction. Therefore, the end portion enters the recessed portion and is pressed by the protruding portion, and the end portion can be molded without any delay.
Preferably, the skin material is a thermoplastic material formed by providing a foam layer on the back surface side of the skin. Thereby, a skin and a foaming layer can be shape | molded integrally, and a molded component with a cushioning property can be efficiently produced by arrange | positioning a foaming layer toward the base material side.

On the other hand, the vacuum forming die of the present invention comprises a first die in which a dent is formed and a second die in which a protrusion to be inserted into the dent is formed. The first die and the second die In a vacuum forming mold in which a skin material is placed between the mold and the skin material is molded by closing the mold, the cutting blade is provided at the protruding portion, and the cutting blade insertion recess is formed at the bottom of the recessed portion, and the mold is closed. Then, the cutting blade forms a cut in the skin material, and the projecting portion presses the end of the skin material around the cut surface against the bottom of the recess, thereby forming a drawn product having an opening at the bottom of the recess. And
Thereby, only by narrowing the space | interval of a 1st type | mold and a 2nd type | mold, a cut blade contact | abuts a skin material and a cut is formed in a skin material. Therefore, by closing the mold, thinning of the skin material can be suppressed and the skin material can be formed into a deep-drawn shape. Moreover, since the cutting blade insertion recessed part is formed in the bottom part of a recessed part, it does not become an obstacle of mold closing.

  According to the vacuum forming method of the present invention, when the vacuum forming die is closed, the cut edge is formed in the skin material by the cutting blade, and the edge of the skin material around the cut edge enters the recessed portion at the outer peripheral portion of the protruding portion. Therefore, the skin material can be formed without reducing the thickness of the skin material. At this time, the skin material can be brought into close contact with the base material without causing a gap between the base material and the skin material. Moreover, even if the skin material is returned to room temperature, the skin material is prevented from being thinned, and therefore, the skin material is difficult to peel off from the base material as the skin material contracts. Therefore, it is possible to perform the molding efficiently with a high yield and to ensure the quality of the molded product.

  On the other hand, according to the vacuum forming die of the present invention, only by closing the mold, a cut edge is formed in the skin material with the cutting blade, and the end portion of the skin material around the cut edge is inserted into the recessed portion at the outer peripheral portion of the protruding portion. be able to. Thereby, a skin material can be shape | molded without making a skin material thin, and the quality of a molded product can be ensured. Moreover, since the thinning of the skin material is suppressed, it is not necessary to use a thick skin material in advance, and the material cost can be reduced.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing the main part of the vacuum forming die of the present invention. The vacuum forming die 10 of the present invention includes a female die 20 as a first die on which a die surface is formed, a male die 30 as a second die having a shape corresponding to the die surface of the first die, Consists of.

  The mold surface of the female mold 20 is formed with a recess 21 for shaping a deep drawing shape. For example, as shown in FIG. 1, the female mold 20 has a first convex part 22 having a triangular cross section formed at an end of the female mold 20 and a second convex part 23 having a rectangular cross section. Prepare. Therefore, the recess 21 is formed as a deep recess surrounded by the inner surface 22a of the first protrusion 22, the outer surface 23a of the second protrusion 23, and the bottom 21a.

  On the other hand, a protrusion 31 corresponding to the recess 21 of the female mold 20 is formed on the mold surface side of the female mold 20 in the male mold 30. For example, as shown in FIG. 1, the male mold 30 includes a first recess 32 having a triangular cross section formed at an end of the male mold 30 and a second recess 33 having a rectangular cross section with a gap therebetween. ing. Therefore, the protrusion 31 is formed as a bulge surrounded by the inner surface 32a of the first recess 32, the outer surface 33a of the second recess 33 and the protrusion 31a.

  As will be described later with reference to FIG. 3, after the skin material 43 is disposed between the female mold 20 and the male mold 30 and the base material 44 serving as an insert is placed on the mold surface of the female mold 20. Since the mold is closed, the mold surface of the female mold 20 and the surface of the male mold 30 corresponding to the mold surface are formed with a margin for the thickness of the skin material 43 and the base material 44. Here, the female mold 20, the male mold 30, and the base material 44 are also called a core mold, a cavity mold, and a core material, respectively.

In the present invention, the protruding portion 31 of the male mold 30 as the second mold is provided with a cutting blade 34 on the protruding surface 31 a, that is, on the recessed portion 21 side of the female mold 20.
FIG. 2 is a perspective view of the protrusion 31 of the male mold 30 shown in FIG. As shown in FIG. 2, the cutting blade 34 has a predetermined length. The cutting blade 34 is provided such that its longitudinal direction coincides with the longitudinal direction of the protruding portion 31 of the male mold 30. Here, the predetermined length of the cutting blade 34 is set by, for example, the size of the protruding portion 31 and the recessed portion 21 and the material and thickness of the skin material 43.

  In addition to the sawtooth shape in which several triangular teeth are continuous as shown in FIG. 2, the cutting blade 34 is provided with a predetermined length extending in a triangular shape in cross section in which the recessed portion 21 side is thinner than the root side of the protruding portion 31. The shape may be sufficient. A saw-tooth shape as shown in FIG. 2 is preferable. This is because the cut blade 34 comes into contact with the skin material 43 by bringing the skin material 43 close to the mold surface of the female mold 20 or by narrowing the interval between the female mold 20 and the male mold 30 as described later. This is because the smaller the area of the abutting surface, the easier it is to cut the skin material 43 to form a cut. Here, the cutting blade 34 may be provided on the male mold 30 by attaching the cutting blade 34 to the protruding portion 31, or may be integrally formed when the protruding portion 31 of the male mold 30 is formed. Good.

  On the other hand, as shown in FIG. 1, a cut blade insertion portion 24 for inserting the cut blade 34 is provided on the bottom surface 21 a of the recessed portion 21 of the female mold 20. Thereby, the cutting blade 34 can be escaped at the time of mold closing. The depth of the cutting blade insertion recess 24 may be at least the length of the cutting blade 34. Thereby, the skin material 43 etc. can be pinched | interposed by the bottom face 21a of the recessed part 21 of the female type | mold 20, and the protrusion surface 31a of the protrusion part 31 of the male type | mold 30, and a mold can be closed completely.

Next, a vacuum forming method will be described in which a skin material 43 is formed using the vacuum forming die 10 and is brought into close contact with the substrate 44 on the die surface of the female die 20 to produce a drawn product having a depression.
3 is a cross-sectional view showing each step of the vacuum forming method using the vacuum forming mold 10 of FIG. 1, and FIG. 4 is a cross-sectional view showing each step following the step shown in FIG.
First, as shown in FIG. 3A, the skin material 43 is disposed between the female mold 20 and the male mold 30. The skin material 43 is held by a clamp device (not shown). The skin material 43 is made of a thermoplastic material that is softened by heating. For example, the back surface of the skin 41 is lined with a foam layer 42. Here, the foam layer 42 is obtained by foaming a resin or the like with a foaming agent, and has cushioning properties.
Further, before and after the arrangement of the skin material 43, the base material 44 is placed on the mold surface of the female mold 20 as shown in FIG. A recess 44a corresponding to the depression of the drawn product is formed in the base material 44, and an opening is formed in the bottom 44b of the recess 44a so that the cutting blade 34 can be inserted.
Here, as shown in FIG. 3A, until the female mold 20, the male mold 30, the skin material 43, and the base material 44 are arranged, the skin material 43 is heated and softened so that it can be molded.

Next, the distance between the female mold 20 and the male mold 30 is reduced by moving the male mold 30 and the clamping device in the direction indicated by the arrow a in FIG. Then, the ridge line portion 44 c of the base material 44 positioned on the ridge line 22 b of the first convex portion 22 contacts the foam layer 42 of the skin material 43. Further, the edge portion 44 d of the base material 44 located on the edge portion 23 b of the second convex portion 23 contacts the foam layer 42 of the skin material 43. Simultaneously with the contact of the foam layer 42 to the base material 44, the first convex portion-side outer peripheral portion 31b and the second convex portion-side outer peripheral portion 31c of the outer peripheral portion at the tip of the projecting portion 31 abut against the skin 41, and the projecting portion The protrusion 31 is being inserted into the recess 21 while the outer periphery of 31 slides on the skin 41.
At this time, as shown in FIG. 3B, when the cut blade 34 provided on the protruding portion 31 of the male mold 30 comes into contact with the skin material 43 and the male mold 30 is further lowered, the cut blade 34 forms the skin material 43. A cut is made, and a cut 43 a is formed in the skin material 43.

  And as the 1st convex part side outer peripheral part 31b slides the surface of the skin material 43 among the outer peripheral parts of the protrusion part 31, as shown by the arrow b, the edge part 43b of the skin material 43 around the cut 43a is shown. It is made to enter while expanding so that the 1st convex part side of the dent part 21 may be met. At the same time, the second convex portion side outer peripheral portion 31c of the outer peripheral portion of the protruding portion 31 slides on the surface of the skin material 43, so that the end portion 43c of the skin material 43 around the cut end 43a is indicated by an arrow c. Into the second convex portion side of the concave portion 21, it is allowed to enter while expanding. At this time, by sucking air between the female die 20 and the skin material 43 from a vacuum suction hole (not shown) provided in the female die 20, end portions 43b of the skin material 43 around the cut end 43a, 43c can be efficiently inserted along the side surfaces 22a and 23a of the recessed portion 21. Further, since the skin material 43 is softened by heating, the end portions 43b and 43c are combined with the fact that the end portions 43b and 43c of the skin material 43 around the cut edge 43a are somewhat adhered to the cutting blade 34. Can enter the recess 21.

Then, the male mold 30 is moved toward the female mold 20 in the direction indicated by the arrow in FIG. At this time, the protruding portion 31 is provided so that the cutting blade 34 protrudes, but the cutting blade insertion recess 24 is formed at a corresponding portion of the female mold 20, and therefore the cutting blade 34 is replaced with the cutting blade insertion recess 24. The cutting blade 34 does not become an obstacle to molding. In addition, the protruding surface 31a of the protruding portion 31 can be brought as close to the bottom surface 21a of the recessed portion 21 as possible. Therefore, the skin material 43 can be formed into a deep drawing shape with a depression along the base material 44 placed on the mold surface of the female die 20.
At this time, the skin material 43 is formed with a cut 43a, so that a deep-drawn edge 43d of the skin material 43 is formed without covering the central portion of the bottom surface 21a. Therefore, since the skin material 43 does not extend more than necessary, a portion of the skin material 43 that faces the inner surface 22a of the first convex portion 22 across the base material 44 is not expanded. Further, the portion facing the outer surface 23a of the second convex portion 23 across the base material 44 is not stretched. Therefore, thinning of the skin material 43 can be suppressed. That is, since the skin material 43 is not pulled more than necessary, the skin material 43 is not thinned and the skin material 43 is not torn.

  Finally, the skin material 43 is returned to room temperature, the skin material 43 is molded from the female mold 20 and the male mold 30, and the molded part 45 integrated with the base material 44 is removed and removed. FIG. 4B shows the drawn product 45 after demolding. The draw-formed product 45 has a recess 45a, and has an opening at the bottom 45b of the recess 45a. At this time, since the temperature is lower than the temperature at the time of molding, the skin material 43 shrinks, but the skin material 43 does not become thinner than the conventional material, so the foam layer 42 of the skin material 43 is in close contact with the base material 44, Peeling of the skin material 43 from the material 44 can be prevented.

As described above, the vacuum forming die 10 is provided with the cutting blade 34 for forming the cut 43a to the skin material 43 in the protruding portion 31 of the male die 30 as the second die, and the female as the first die. A cutting blade insertion recess 24 is provided for inserting the cutting blade 34 into the recess 21 of the mold 20 and allowing the cutting blade 34 to escape. Therefore, when the base material 44 is placed on the mold surface of the female mold 20 and the mold is closed, the cut edge 34a is formed in the skin material 43 by the cutting blade 34, so that the skin material 43 is prevented from being thinned, and the skin material 43 can be brought into close contact with the substrate 44 while being formed into a deep drawing shape. That is, no gap is formed between the skin material 43 and the base material 44. Then, when the skin material 43 is returned to room temperature, the skin material 43 can be prevented from peeling off from the base material 44.
Further, in the state of FIG. 3A, the male mold 30 is pressed in the state of FIG. 4A by applying an adhesive to the surface of the base material 44, that is, the surface on the skin material 43 side. Then, the skin material 43 being molded is in close contact with the base material 44. At this time, pressure is applied from the skin material 43 to the base material 44 by the pressing of the male mold 30, so that the skin material 43 and the base material 44 can be bonded.

  The embodiment of the present invention has been described in detail above, but the present invention can be variously modified within the scope of the invention described in the claims. For example, in the above description, the base material 44 has a recess 44a corresponding to the recess 45a of the drawn product 45, and the bottom of the recess 44a has an opening. , Formed in a shape along the recessed portion 21 and the cutting blade insertion recessed portion 24 of the female mold 20, the skin material 43 is molded and brought into close contact with the base material 44, and then demolded to open the bottom of the recess 45 a. You may make it do.

It is sectional drawing which shows the principal part of the vacuum forming die of this invention. FIG. 2 is a perspective view of a male protrusion shown in FIG. 1. It is sectional drawing which showed each process of the vacuum forming method by the vacuum forming die of FIG. It is sectional drawing which showed each process following the process shown in FIG. It is a perspective view of the instrument panel as a molded article. It is sectional drawing which showed the process of mold closing at the time of shape | molding an instrument panel. (A) is sectional drawing which showed the process of mold closing at the time of shape | molding an instrument panel, (B) is sectional drawing of the instrument panel at the time of demolding.

Explanation of symbols

10 Vacuum forming mold 20 Female mold (first mold)
21 recessed part 21a, 45b bottom face 22 1st convex part 22a inner side surface 22b ridge line 23 second convex part 23a outer side surface 23b edge part 24 cutting blade insertion recessed part 30 male type (second type)
31 Protruding portion 31a Protruding surface 31b, 31c Outer peripheral portion 32 First concave portion 32a Inner side surface 33 Second concave portion 33a Outer side surface 34 Cutting blade 41 Skin 42 Foamed layer 43 Skin material 43a Cut edge 43b, 43c End portion 43d Edge portion 44 Base material 44a , 45a Dimple 44b, 45b Bottom 44c Ridge 44d Edge 45 Draw

Claims (5)

A vacuum forming mold comprising: a first mold in which a recessed portion is formed; and a second mold in which a protruding portion to be inserted into the recessed portion is formed and a cutting blade is provided on the protruding surface of the protruding portion. A skin material is disposed between the first mold and the second mold, and the mold is closed and the inside of the mold is vacuum-sucked, whereby the skin is placed on the substrate placed on the first mold. A vacuum forming method for producing a draw-formed product having a depression by closely adhering materials,
Narrowing the distance between the first mold and the second mold and forming a cut in the skin material with the cutting blade;
Moving the second mold to the first mold side, and the projecting portion pressing the end of the skin material around the cut edge against the substrate;
A vacuum forming method characterized by:   2. The base material according to claim 1, wherein a concave portion corresponding to the depression of the drawn product is formed in the base material, and an opening into which the cutting blade is inserted is formed in a bottom portion of the concave portion. Vacuum forming method.   3. The method according to claim 1, wherein the step of forming the cut end and the step of pressing the end portion are performed by vacuum suction in a mold through a vacuum suction hole provided in the first mold. Vacuum forming method.   The vacuum forming method according to any one of claims 1 to 3, wherein the skin material is a thermoplastic material having a foam layer provided on the back side of the skin. A skin material comprising a first mold in which a recess is formed and a second mold in which a protrusion to be inserted into the recess is formed, and the skin material between the first mold and the second mold In a vacuum forming mold for forming the skin material by closing the mold and closing the mold,
A cutting blade is provided in the protruding portion, and a cutting blade insertion recess is formed at the bottom of the recessed portion,
When the mold is closed, the cutting blade forms a cut in the skin material, and the projecting portion presses the end of the skin material around the cut surface against the bottom of the dent, and has an opening at the bottom of the dent. A vacuum forming die characterized by forming a product.

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