JPH0334454B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Field of Industrial Application The present invention relates to a vacuum forming mold used for forming a synthetic resin sheet into a predetermined shape.

(2) Prior Art The applicant previously developed an electroformed shell that is faithful to the model and has air permeability by electroforming the surface of a precision model. (See Japanese Patent Application No. 60-2669).

After the electroformed shell is released from the precision model, it is attached to a predetermined support frame and subjected to a molding operation.

(3) Problems to be solved by the invention However, since the electroformed shell has a very thin wall thickness and low rigidity, it is said that it is easily deformed when impact force is applied during mold fitting, manufacturing of a molded product, etc. There's a problem.

Furthermore, since the electroformed shell is tightly adhered to the precision model, it is difficult to release the mold from the mold, and there is also the problem that the electroformed shell is deformed during demolding due to internal stress generated during the electroforming process. This deformation is likely to occur in products that have large and complicated molded parts, such as electroformed shells used to mold vehicle instrument panels.

An object of the present invention is to provide the vacuum forming mold that can solve the above problems.

B. Structure of the Invention (1) Means for Solving the Problems The present invention comprises an electroformed shell having air permeability and having a mounting flange connected to the outer periphery of a molding part for molding a synthetic resin sheet into a predetermined shape. ; The downward opening of the frame body is covered by the molded part, and the support flange around the downward opening is overlappingly connected to the mounting flange, and the molded part is covered by the hanging member provided on the frame body. It is characterized by comprising: a supporting frame to be suspended; and a back-up body having air permeability and housed in the frame main body and integrally joined to the back surface of the molded part.

(2) Effect Even if an impact force is applied to the molded part of the electroformed shell during mold matching or manufacturing of the mold, the molded part will not be deformed because it is reinforced by the back-up body. Further, since the mounting flange portion of the electroformed shell is overlappingly connected to the support flange portion of the support frame and the molded portion is suspended by the suspension member, the molded portion is not deformed by the weight of the backup body.

Further, before the electroformed shell is released from the precision model, it is possible to suspend the electroformed shell on a support frame, thereby facilitating the release work and preventing deformation of the electroformed shell.

(3) Example A vacuum forming mold 1 for molding a vehicle instrument panel has a nickel electroformed shell 2 shown in FIGS. 1 and 2 supported by a support frame 8 as shown in FIG. Further, it is constructed by accommodating a backup body 19 within the support frame 8.

The electroformed shell 2 is rectangular in plan, has air permeability, and has a thickness of about 0.6 to 3 mm.
The electroformed shell 2 is composed of a molded part 2a having an uneven part for molding a synthetic resin sheet into the shape of an instrument panel, and a mounting flange part 2b connected to the outer periphery of the molded part 2a and attached to a support frame to be described later. Ru. On the front surface of the electroformed shell 2, that is, on the overlapping surface 4 of the sheets facing downward in FIG. 2, an uneven pattern p faithful to cowhide leather is formed as shown in FIG. Further, as shown in FIG. 4, numerous ventilation holes 5 are formed in the electroformed shell 2 so as to be uniformly distributed throughout the thickness thereof, and these ventilation holes 5 are used as vacuum suction holes. The openings 5a of the ventilation holes 5 on the sheet overlapping surface 4 are arranged at a pitch of about 0.2 mm in the vertical and horizontal directions, and their diameter is 0.03 to 0.05 mm.
It is. As described above, since the opening 5a of the vent hole 5 has an extremely small diameter, the uneven pattern p is not damaged in any way.

As shown in FIG. 1, a large number of nut members ₆₁ are welded to the back surface of the molded part 2a of the electroformed shell 2 by stud welding, arranged vertically and horizontally so as to be distributed over the entire molded part 2a. Also, the mounting flange part 2
A large number of nut members ₆₂ are also welded to the rear surface of the mounting flange portion 2b by stud welding so as to be distributed over the entire mounting flange portion 2b. These nut members 6 ₁ ,
6 ₂ is used to suspend the electroformed shell 2 on a support frame to be described later.

When the stud welding method is applied in this manner, there is an advantage that even if a large number of nut members 6 ₁ and 6 ₂ are welded to the extremely thin electroformed shell 2, no welding distortion occurs in the electroformed shell 2.

A fiber-reinforced synthetic resin body 3 is bonded to the entire back surface of the mounting flange portion 2b. This fiber-reinforced synthetic resin body 3 is made of reinforcing fibers and a thermosetting synthetic resin filled and composited with the reinforcing fibers, and the reinforcing fibers include long fibers made of glass fibers, carbon fibers, metal fibers, etc., or one of these fibers. Examples of thermosetting synthetic resins include epoxy resins and the like.

In producing the fiber-reinforced synthetic resin body 3, the nut member ₆₂ is welded to the entire back surface of the mounting flange portion 2b of the electroformed shell 2, and then the fibers are arranged with a predetermined thickness and orientation. This is impregnated with the heat-strengthening synthetic resin liquid and the resin is cured by heating, and at the same time as this fiber-reinforced synthetic resin body 3 is produced, it is integrally joined to the mounting flange portion 2b.

The production of this fiber-reinforced synthetic resin body 3 consists of the electroformed shell 2
This is done before the mold is released, that is, when the electroformed shell 2 is on the precision model M.

In this way, the mounting flange 2b and the fiber-reinforced synthetic resin body 3 are attached to the outer periphery of the molded part 2a.
When a more rigid composite part 7 is formed, deformation of the molded part 2a is suppressed by this composite part 7.
The shape retention of the electroformed shell 2 is improved, and deformation of the electroformed shell 2 due to internal stress generated in the electroforming process during mold release can be prevented.

As shown in FIGS. 5 and 6, the electroformed shell 2 has a first movable part 9 ₁ that is attached to a support frame 8 and can be raised and lowered.
The first movable part 9 _{1 and} the second movable part 9 2 are disposed below the movable part 9 ₂ so as to be able to rise and fall freely, and are used for manufacturing an instrument panel.

In the first movable part 9 ₁ , the support frame 8 is connected to the top wall 1
A frame body 8a having a plane rectangular box shape with 0
A plurality of angle-shaped crosspieces 8b are arranged at equal intervals perpendicular to the longitudinal direction of the frame body 8a in the vicinity of the downward opening of the frame body 8a, and have both ends welded to the inner surface of the frame body 8a. It consists of a support plate 8c whose lower end surface is welded to the top wall 10 and to each crosspiece 8b.

The downward opening of the frame body 8a is covered by the molded part 2a of the electroformed shell 2, and the support flange 11 protruding from the periphery of the downward opening is the back surface of the mounting flange 2b of the electroformed shell 2, and therefore the composite It is superimposed on the fiber-reinforced synthetic resin body 3 in the section 7 via the backing plate 12, and both the flange sections 2b, 11 are connected by a large number of tightening bolts 13 and nuts 14 along the periphery of the frame body 8a. In this case, the composite portion 7 has excellent deformation resistance and will not deform even if it is tightened with the tightening bolt 13 or the like. A vacuum sealing material 15 is interposed between the support flange portion 11 and the composite portion 7 on the inside of the backing plate 12 .

In the nut member 6 ₁ welded to the molded part 2 a of the electroformed shell 2 , the nut members _{6 1 in} each row in FIG. A cylindrical spacer 1 is provided between each crosspiece 8b.
7 ₁ is interposed, the crosspiece 8b and the cylindrical spacer 1
The suspension bolt 18 ₁ passing through 7 ₁ is the nut member 6 ₁
is screwed onto. The cylindrical spacer 17 ₁ has the function of regulating the tightening force of the suspension bolt 18 ₁ to a predetermined amount to prevent deformation of the mounting flange portion 2b.

Thus, each nut member 6 ₁ , the crosspiece 8b and the suspension bolt 18 ₁ constitute a suspension member that suspends the molded part 2a.

Angle members 16 are welded to the inner surface of the frame body 8a in correspondence with the respective nut members ₆₂ welded to the back surface of the mounting flange portion 2b of the electroformed shell 2. A cylindrical spacer 17 2 is interposed between each nut member 6 ₂ and each angle member 16, and a suspension bolt _{18 2 passing} through the angle member 16 and the cylindrical spacer 17 ₂ is screwed onto the nut member 6 ₂ . Ru.

Inside the support frame 8, there is mainly a molded part 2 of the electroformed shell 2.
A back-up body 19 for reinforcing a is housed and is integrally joined to the electroformed shell 2. The back-up body 19 is made up of a number of adjacent steel balls made of stainless steel or the like having excellent corrosion resistance, which are disposed on the side of the electroformed shell 2, and are partially bonded with thermosetting synthetic resin such as epoxy resin for ventilation. a first layer 19 ₁ with air permeability, and a second layer 19 ₁ with air permeability, in which numerous adjoining glass particles laminated on the first layer 19 1 are partially bonded with the same thermosetting synthetic resin as described above; Layer 19 consists of ₂ layers.

Even if the backup body 19 is provided on the back side of the electroformed shell 2 in this way, the mounting flange portion of the electroformed shell 2
b. Therefore, the composite part 7 is connected to the support frame 8 and the support flange part 11 in an overlapping manner, and the composite part 7 and the molded part 2a are connected to each of the beams 8b and the angle members 16 by a large number of suspension bolts 18 ₁ and 18 ₂ . Since the electroformed shell 2 is suspended by the back-up body 19, problems such as sagging and deformation of the electroformed shell 2 due to the weight of the back-up body 19 do not occur.

When forming the first layer 19 ₁ , a thin resin layer made of the thermosetting synthetic resin is placed on the surface of the frame body 8b without the top wall 10 on the back side of the electroformed shell 2, as shown in FIG. 70-150μ steel ball with R ₁ 2
0 is injected in a predetermined amount, and then the steel balls 20 and the resin layer are injected.
R ₁ is heated to 70 to 80° C. to bond portions of the resin layer R ₁ located at the contact points between adjacent steel balls 20, thereby forming a void V ₁ surrounded by each bond point. Continuous pores are formed in the first layer 19 ₁ by this void V ₁ . When the steel balls 20 are joined together, the first layer 19 ₁
and the electroformed shell 2 are also joined by the resin layer _R1 .

In addition, when forming the second layer 19 ₂ , a member (not shown) having the same shape as the recess 19 a is suspended within the frame body 8 b to form the recess 19 _a to reduce weight. As shown in FIG. 8, a predetermined amount of glass particles 21 of 400 to 600 μm having the thin resin layer R ₂ on the surface is injected, and then the glass particles 21 and the resin layer R ₂ are heated to 70 to 80°C. The parts of the resin layer R ₂ located at the contact points between adjacent glass particles 21 are bonded to form a void V ₂ surrounded by each bond point. These voids V ₂ form continuous pores in the second layer 19 ₂ . When bonding the glass particles 21 to each other, the resin layer is also applied between the first layer ₁₉₁ and the second layer ₁₉₂ .
Each is joined by R ₂ .

A plurality of windows 22 are formed in the support plate 8c, and these windows 22 prevent the flow of the glass particles 21 from being obstructed by the support plate 8c when the glass particles 21 are injected.

A cooling pipe 23 is embedded in the first layer 19 ₁ in a meandering manner so as to uniformly cool the entire molded part 2a. In this case, since the first layer 19 ₁ is mainly composed of the steel balls 20, it has good thermal conductivity and can therefore efficiently cool the molded part 2a. Furthermore, the first layer 19 ₁ is reinforced by embedding the cooling pipe 23 in a meandering manner.

A vacuum pump 2 is connected to the inside of the support frame 8 via a switching valve 24.
5 ₁ and the blower 26.

The second movable part ₉₂ is configured as follows.

A pressing mold 29 is fixed to an upward opening of a planar rectangular support frame 28 provided with a bottom wall 27 and is fitted into the molding part 2a. A recess 30 for fitting the core material C is formed on the upper surface of the pressing mold 29, and a plurality of vacuum suction holes 31 are formed in the portion of the pressing mold 29 facing the molding portion 2a so as to penetrate through that portion. is formed. The inside of the support frame 28 is connected to a vacuum pump 25 ₂ .

The instrument panel consists of a synthetic resin sheet S and a core material C, and the synthetic resin sheet S can be a single sheet made of polyvinyl chloride or the like, or the sheet can be used as a skin layer, and a polypropylene foam sheet can be used as a cushion layer. This applies to laminated sheets that have been bonded together.

The core material C is made of a plate made of ABS resin or the like, with a plurality of small-diameter vacuum suction holes 32 formed therein, and this plate is molded to fit into the recesses 30 of the pressing die 29.

Next, manufacturing of the instrument panel will be explained.

A hot melt adhesive is applied as an adhesive to the surface of the core material C, and the adhesive is softened by heating.

As shown in FIG. 5, raise the first movable part ₉₁ ,
Further, the second movable part 9 ₂ is lowered to open the electroformed shell 2 and the pressing mold 29, and the core material C is fitted into the recess 30 of the pressing mold 29 with its adhesive coated surface facing outward. The suction hole 32 is matched with each vacuum suction hole 31 of the press die 29.

A synthetic resin sheet S consisting of a skin layer a and a cushion layer b is heated to approximately 180°C to soften it,
The synthetic resin sheet S is placed first with its skin layer a facing up.
and disposed between the second movable parts 9 ₁ and 9 ₂ .

As shown in FIG. 9, lower the first movable part ₉₁ ,
Further, the second movable portion 9 ₂ is raised to sandwich the synthetic resin sheet S between the electroformed shell 2 and the pressing die 29 . Since the synthetic resin sheet S is pressed against the surface of the electroformed shell 2 by the pressing mold 29, it has good conformability to the surface.

The inside of the support frame 8 of the first movable part 9 ₁ is connected to a vacuum pump 25 ₁ via the switching valve 24, and the synthetic resin sheet S is vacuum-suctioned by the vacuum pump 25 ₁ .
The molded part 2a of the electroformed shell 2 has countless fine ventilation holes 5 throughout it, and the synthetic resin sheet S is sufficiently blended into the surface of the molded part 2a by the press die 29, so that The sheet S tightly adheres to the entire surface of the molding section 2a, whereby the uneven pattern p is accurately and clearly transferred to the surface of the sheet S, and at the same time, the sheet S is molded into the shape of the molding section 2a.
Since the forming part 2a is cooled by the cooling pipe 23, the sheet S is immediately cooled, and the uneven pattern p and shape collapse are prevented.

The vacuum pump 25 ₂ on the second movable part 9 ₂ is operated to press the molded body formed from the sheet S into the press mold 2.
9 and the surface of the core material C, and the first
The inside of the support frame 8 of the movable part ₉₁ is switched to the blower 26 side via the switching valve 24 to apply blow pressure to the molded article.

As a result, the molded body is released from the molded part 2a and is closely attached to the core material C to be integrally joined thereto.
Since the molded body is in close contact with the molded part 2a, the combination of the vacuum suction action and the blow pressure is
This is an extremely effective means for promoting mold release of the molded product.

The blower 26 is stopped, and the inside of the support frame 28 of the second movable part 9 ₂ is switched to the atmosphere, and then the first movable part 9
₁ is raised, and the second movable part ₉₂ is lowered to remove the instrument panel from the press die 29.

The surface of this instrument panel has a concavo-convex pattern P clearly formed thereon without running off, and the bonding strength between the molded body made of the synthetic resin sheet S and the core material C is high, resulting in excellent durability.

During the manufacturing process, an impact force is applied to the molded part 2a of the electroformed shell 2 when it fits into the press die 29, but since the molded part 2a is reinforced on the back side by the back-up body 19, the molding is not possible. There is no possibility that the portion 2a will be deformed.

Next, the production of the electroformed shell 2 will be explained with reference to the principle diagram shown in FIG.

(a) Process The uneven pattern p is made from cowhide using epoxy resin.
A precision model M having the following is produced.

(b) Process The surface of the precision model M having the uneven pattern p is subjected to silver mirror treatment to form a thin conductive layer C _O made of silver,
An uneven pattern p is made to appear on the entire surface of the conductive layer _CO .

(c) Process The precision model M is surrounded by an insulating cylinder T, and a conductive layer is placed around it.
Numerous polystyrene particles P _S with a diameter of 0.2 mm are laminated as fine particles that can be eluted over the entire surface of _CO to form a layer L, and on top of this, an anti-lifting body W with glass particles encased in a nylon net is formed. to bring the bottom layer of polystyrene particles P _S into close contact with the surface of the conductive layer _CO . This allows each polystyrene particle in the bottom layer to
P _S is in close contact with the surface of the conductive device C _O in point contact.

(d) Process: Put the precision model M into the nickel plating solution S _O in the electroforming tank Ta, connect the conductive layer C _O to the (+) pole of the power source E _S ,
In addition, the electrode E facing the anti-lifting body W is connected to the power source.
Connect each to the (-) pole of E _S and perform electroforming on precision model M. During this electroforming process, the precipitated nickel n is removed from the conductive layer C _O and the polystyrene particles P _S except for the areas in close contact with the polystyrene particles P _S of the conductive layer C _O.
The spaces between and adjacent polystyrene particles P _S are filled, thereby obtaining an electroformed shell 2 having an uneven pattern p. The thickness of the electroformed shell 2 is set to be thinner than the particle layer 1 so that the upper peripheral surface of the polystyrene particles P _S in the uppermost layer is slightly exposed from the electroformed shell 2.

After releasing the electroformed shell 2 obtained through the above steps and peeling the electroformed shell 2 from the conductive layer C _O , the polystyrene particles P _S are immersed in a solvent such as toluene or methylene chloride. It is eluted from the cast shell 2 and forms the vent hole 5 shown in FIG. In this case, a layer of particles l is formed on the front and back surfaces of the electroformed shell 2 having the uneven pattern p.
Since a part of the polystyrene particles P S are exposed, the polystyrene particles P _S melt from these exposed parts and form the openings 5a and 5b.
are formed inside the electroformed shell 2, and in the interior of the electroformed shell 2, there are pores 5c after elution of the polystyrene particles P _S and connections between the adjacent pores 5c at the points of contact between the adjacent polystyrene particles P _S , etc. A hole 5d is formed.

This results in extremely small diameter openings 5 on both the front and back sides.
An electroformed shell 2 having numerous ventilation holes 5 having holes 5a and 5b is obtained.

In addition to the polystyrene particles _PS , paraffin particles, aluminum particles, etc. can be used as elutable particles. Paraffin particles are eluted from the electroformed shell 2 by heating, and aluminum particles are eluted from the electroformed shell 2 by heating. Alternatively, it is eluted from the electroformed shell 2 by chemical etching treatment.

Next, the demolding work of the electroformed shell 2 will be explained.As shown in Fig. 11, the electroformed shell 2 on the precision model M is
A large number of nut members 6 ₁ and 6 ₂ are welded to the back surface of the holder as described above. Further, the fiber-reinforced synthetic resin body 3 is joined to the entire back surface of the mounting flange portion 2b as described above.

Next, as shown in FIG. 12, the electroformed shell 2 is covered with the support frame 8 to which the top wall 10 is not welded, and the electroformed shell 2 is attached to each crosspiece 8b and each angle member 16 as described above.
Cylindrical spacers 17 ₁ , 17 ₂ and suspension bolt 1
Suspended via 8 ₁ and 18 ₂ .

Thereafter, the support frame 8 is pulled up and the electroformed shell 2 is released from the precision model M.

At the time of this mold release, the composite part 7 and the support frame 8
Since the electroformed shell 2 retains its shape, deformation of the electroformed shell 2 due to internal stress generated in the electroforming process is prevented.

Figure 13 shows a modification in which a large number of suspension bolts 18 ₃ , 18 ₄ are welded to the back surface of the electroformed shell 2 by stud welding, and nuts 33 ₁ , 33 ₂ are screwed onto each bolt 18 ₃ , 18 ₄ . Give an example.

C Effects of the Invention According to the present invention, the molded part of the electroformed shell is reinforced with a back-up body, so even if an impact force is applied to the molded part during mold matching or manufacturing of the molded product, the molded part will deform. There's nothing to do. Further, since the mounting flange portion of the electroformed shell is overlappingly connected to the support flange portion of the support frame and the molded portion is suspended by the suspension member, the molded portion is not deformed by the weight of the back-up body. Therefore, the vacuum forming mold according to the present invention has excellent durability.

Furthermore, since a support frame is installed on the back side of the electroformed shell, before the electroformed shell is released from the precision model, the electroformed shell is suspended from the support frame and the mold release operation is performed via the support frame. This makes it possible to easily perform the mold release operation and to maintain the shape of the electroformed shell with the support frame to prevent deformation of the electroformed shell due to internal stress generated during the electroforming process.

[Brief explanation of drawings]

Figure 1 is a rear view of the electroformed shell, Figure 2 is Figure 1-
3 is a front view of the electroformed shell, FIG. 4 is a sectional view taken from line 3 - FIG. FIG. 5 is a line sectional view, FIG. 7 is an enlarged sectional view of a part of the first layer in the backup body, FIG. 8 is an enlarged sectional view of a part of the second layer in the backup body, and FIG. 9 is an enlarged sectional view of a part of the second layer in the backup body. A longitudinal cross-sectional view during manufacturing work, Fig. 10 is an explanatory diagram of the manufacturing process of the electroformed shell, Fig. 11 is a longitudinal cross-sectional view showing the relationship between the electroformed shell and the precision model, and Fig. 12 is the demolding work of the electroformed shell. FIG. 13 is a longitudinal sectional view of a main part of a modified example of a suspension structure for an electroformed shell. S...Synthetic resin sheet, 2...Electroformed shell, 2a...
...Molding part, 2b...Mounting flange part, 8...Support frame, 8a...Frame body, 11...Support flange part,
19... Backup type, 6 ₁ , 8b, 18 ₁ ...
A nut member, a crosspiece, and a suspension bolt that constitute a suspension member.

Claims (1)

[Claims] 1. A breathable electroformed shell with a mounting flange connected to the outer periphery of a molding part that molds a synthetic resin sheet into a predetermined shape; a downward opening of the frame body is covered by the molding part; a support frame that overlaps and connects a support flange on the periphery of the part to the mounting flange, and suspends the molded part by a suspension member provided on the frame main body; A vacuum forming mold consisting of a breathable back-up body integrally joined to the back surface of the mold.