JPS62199426A - Method and apparatus for partially increasing wall thickness in vacuum molding or pressure forming - Google Patents

Abstract

PURPOSE:To easily and certainly perform the partial increasing (padding) of the thickness of a sheet, by injecting a resin for padding molding in the part, where a thickness must be increased, of the sheet before performing vacuum molding. CONSTITUTION:A sheet like base material S is softened under heating to be placed on a mold 2 and air is vented from an air vent hole 2b to closely contact said base material S with the mold 2. Next, a reinforcing resin material J is allowed to fill areas FA, FS where the thickness of the sheet like base material S is partially increased from injection ports 3b, 3c to be introduced into the gap between an auxiliary molding surface 3a and the surface of the sheet like base material 3 closely contacted with the mold 2 under pressure. Subsequently, the sheet like base material S of which the thickness is partially increased is solidified under cooling and taken out from the mold 2 to obtain a partially reinforced door lining L.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a molding method for partially increasing the wall thickness of a molded article by vacuum or pressure molding, and an apparatus for performing this molding method. .

[Prior art] In the vacuum forming method or the pressure forming method, when a heated and softened sheet-like base material is brought into close contact with the shaping surface of a mold, the sheet-like base material conforms to the uneven shape of the shaping surface. They are expanded together.

The amount of elongation of this sheet-like base material varies depending on the unevenness of the forming surface, etc., and the elongation rate is higher in the convex top or concave bottom of the molded product than in other parts. Become.

As a result, the wall thickness becomes thinner in the portions where the elongation rate is high, resulting in a disadvantage that local thickness variations occur in the molded product.

In particular, when forming a molded product with a large difference in unevenness, the elongation rate of the sheet-like base material increases locally and the wall thickness in that area becomes thinner, resulting in a local lack of strength in the molded product. There was a risk that this would occur.

Therefore, various measures have been taken in the past in order to eliminate such local strength deficiencies.

For example, when molding a product with large unevenness where the elongation rate is locally high, the thickness of the product at the thinnest part due to high elongation should be made to ensure sufficient strength. However, there is a technology that uses a sheet-like base material that is thicker to accommodate this.

Another technique is to use an adhesive or the like to attach a separate reinforcing material to the back side of a thin part of a molded product that lacks strength.

In this case, the reinforcing material used is a reinforcing material pre-formed to match the shape of the thin part of the product, a cloth-like or mat-like glass fiber, or the like.

Furthermore, FIG. 3 shows another technique, in which a sheet-like base material 32 softened by heating is formed on a forming surface 3 formed in a mold 30 in a vacuum forming method using a mold 30 and an auxiliary mold 31.
Bring it into close contact with 0a. Then, reinforcing sheet pieces 33, which are separate members made of the same material as the sheet-like base material 32 and heated and softened at approximately the same temperature, are placed in the two deep recesses 32a and 32a where the elongation rate is high and the wall thickness is insufficient. Guess .33.

Then, the reinforcing sheet pieces 33, 33 are pressed by the auxiliary die 31 to be brought into close contact with the surface of the sheet-like base material 32 and integrated. In this way, there is a technique to partially increase the wall thickness for reinforcement.

[Problems to be Solved by the Invention] However, the first technique has the disadvantage that the overall thickness of the molded product increases, which increases the weight of the product.

There is also the problem that material costs are high because a thick sheet-like base material is used.

In addition, in the second technique, since an adhesive is applied to the reinforcing material and attached to the sheet-like base material, the work such as applying the adhesive to the reinforcing material and placing the reinforcing material in a predetermined location is troublesome. There was a problem.

In the third technique, the reinforcing sheet piece 33 is 2006
It is high temperature around C, soft and difficult to handle.

Therefore, workability is poor, and for example, since the sheet piece 33 is soft, there is also a problem that it is difficult to place the sheet piece 33 at a predetermined position on the sheet-like base material 32.

Further, as the working time becomes longer, the temperature of the sheet piece 33 decreases and becomes hard, making it difficult to join the sheet piece 32 to the sheet-like base material 32.

Furthermore, in order to place a reinforcing sheet piece 33, which is a separate member, on the sheet-like base material 32 and bring it into close contact, both sheets 32 are
．． It was difficult for air to escape between 33 and 33, and there was a risk that air would accumulate, resulting in poor adhesion.

The present invention was made in view of the above-mentioned problems, and provides a simple and reliable molding method that can partially increase the wall thickness of a molded product in a vacuum or pressure molding method using a mold and an auxiliary mold. The purpose of this invention is to provide a molding device that performs this molding method.

[Means and effects for solving the problems] As a means for solving the above problems, the method according to the present invention involves applying a heat-softened sheet-like base material to the forming surface of a mold using vacuum or compressed air. After they are brought into close contact, a predetermined gap is formed between the surface of the sheet-like base material and the auxiliary mold surface of the auxiliary mold. Next, a predetermined amount of heat-softened resin material is discharged from an injection hole opened at a predetermined position on the auxiliary mold surface of the auxiliary mold and press-fitted into the gap. In this way, a predetermined portion of the sheet-like base material is partially increased in thickness to be formed.

Therefore, if the injection hole is opened in the auxiliary mold surface of the auxiliary mold corresponding to the part where the elongation rate of the sheet-like base material is high (the part where the sheet thickness is thin and the strength is insufficient) and the resin material is replenished, it is possible to The thickness is increased and partially reinforced.

Further, since the work of pasting the reinforcing material with an adhesive or the like and the process of placing it in a predetermined location are no longer necessary, it is possible to fully automate the molding work, and furthermore, uniformity of the product can be achieved.

The apparatus according to the present invention includes a mold having a shaping surface, an auxiliary mold surface whose shape matches at least a portion of the shape of the shaping surface, and an injection hole opening at a predetermined position of the auxiliary mold surface. a resin material supply device that heats and melts the resin material and fills it into the injection hole, and an extrusion device that expels the resin material filled in the injection hole from an opening in the surface of the auxiliary mold. .

With this configuration, the thickness of the reinforced portion can be increased or decreased by adjusting the gap between the auxiliary mold surface and the shaping surface.

Furthermore, the reinforcing range can be expanded or reduced by adjusting the amount of resin material supplied per shot by the resin material supplying device and adjusting the amount of each time of supply.

[Example] Hereinafter, an example of the method and apparatus according to the present invention will be described based on the drawings.

However, as a matter of course, the components, other members, arrangement, etc. described or illustrated in the following explanation examples,
This is not intended to limit the invention, but is merely an illustrative example.

FIG. 1 shows a first embodiment, a method and a molding apparatus for a synthetic resin door lining for automobiles by vacuum forming, and FIG. A step of bringing the sheet-like base material into close contact with the shaping surface using a device;
FIG. 1(B) is a cross-sectional view showing the step of filling the injection hole with a reinforcing synthetic resin material. FIG. 1(C) is a sectional view showing the process of forming the flesh reinforcement part, and FIG. 1(D) is an enlarged sectional view showing the relationship between the shape of the auxiliary mold surface of the auxiliary mold and the tip shape of the piston. , is a cross-sectional view showing the finished door lining.

First, the apparatus for partially increasing the wall thickness using the vacuum forming method according to this embodiment will be described (see FIG. 1(A)).

The vacuum forming apparatus 1 includes a mold 2 mounted and fixed on a substantially horizontal base B, and an auxiliary mold 3 disposed above the mold 2.

A shaping surface 2a is formed on the upper surface side of the mold 2 (in FIG. 1(A)) to match the uneven shape of the door lining L (see FIG. 1(D)), which is the product to be molded. .

A deep recess FA and a deep recess FS are formed in this shaping surface 2a, and the deep recess FA is used for repairing the door lining L when repairing the vehicle body.
The armrest part LA that protrudes from the inside of the door to the inside of the room,
The deep concave portions FS each form a shoulder portion LS.

Further, the mold 2 is formed with a large number of air vent holes 2b that penetrate from the shaping surface 2a to the lower surface.

The plurality of air vent holes 2b are converged on the lower surface of the mold 2, and the piping H connected to the lower surface of the base B.
is connected to.

This pipe H has a branched end, and a vacuum pump P is connected to the end of one branch pipe H□ via a valve HB. Further, a near compressor C is connected to the tip of the other branch pipe H2 via a valve HB2.

On the other hand, on the lower surface side of the auxiliary mold 3, an auxiliary mold surface 3a is provided which is formed to match the uneven shape of the shaping surface 2a.

On this auxiliary mold surface 3a, a protrusion PA is formed at a position corresponding to the deep recess FA of the shaping surface 2a, and a protrusion PS is formed at a position corresponding to the deep recess FS.

This auxiliary type 3 has a vertical movement cylinder 4 vertically installed above.
It is suspended from the lower end of a rod 4a, and is driven in the vertical direction by the operation of the vertical movement cylinder 4, and can be stopped and fixed at a desired height.

The auxiliary mold 3 has a first injection hole 3b and a second injection hole 3c.
are formed through the upper surface 3d of the auxiliary mold 3 toward the auxiliary mold surface 3a.

The lower end of this first injection hole 3b is connected to a protrusion P of the auxiliary mold surface 3a.
It opens near A, and the lower end of the second injection hole 3c opens near protrusion PS.

Further, on the upper surface 3d of the auxiliary mold 3, a resin material supply device 5 is installed which melts the reinforcing synthetic resin material J and supplies it to the injection holes 3b and 3c.

This resin material supply device 5 is composed of a hopper section 6 and a cylinder section 7 connected below the hopper section 6.

The hopper section 6 has a band-shaped heater 6a wrapped around the lower half of its outer periphery, and heats and melts the reinforcing synthetic resin material J stored in the hopper section 6 to fluidize it.

Moreover, the cylinder part 7 communicates with the hopper part 6 at one end side (the right side in FIG. 1(A)), and a screw 7a is disposed inside thereof in the cylinder axial direction.

This screw 7a is a reinforcing synthetic resin material J in a molten state.
is transferred to the tip side of the cylinder where the discharge lower b is formed (left side in FIG. 1(A)) while stirring.

Further, the cylinder portion 7 is provided with a heater 7C.

This heater 7C uses information from temperature sensors such as thermocouples (not shown) disposed in the first injection hole 3b and the second injection hole 3c to provide fluidized reinforcement in the cylinder portion 7. The synthetic resin material J is heated and kept warm to maintain a predetermined melting temperature.

Therefore, the first injection hole 3b and the second injection hole 3c are always filled with reinforcing synthetic resin material J in an optimal state.

Furthermore, two pressure and heat resistant hoses 8 and 9 are connected to the discharge lower b of the cylinder portion 7.

The tip of one pressure- and heat-resistant hose 8 is disposed at the upper part of the first injection hole 3b formed in the auxiliary mold 3, and the tip of the other pressure- and heat-resistant hose 9 is arranged at the upper part of the second injection hole 3C. It is set up.

Further, valve devices 8a and 9a are provided at the respective distal end sides of both pressure and heat resistant hoses 8 and 9 to control the flow rate of the reinforcing synthetic resin material J supplied from the cylinder portion 7.

These valve devices 8a, 9a have - in each injection hole 3b, 3c.
It opens and closes in accordance with the set filling amount for one shot of reinforcing synthetic resin material J to be filled at a time.

Further, on the upper surface of the auxiliary mold 3, a cylinder device 10 for injection is provided.
．． 11 is installed on the axis extending in the hole forming direction of each of the first injection hole 3b or the second injection hole 3c. Each injection hole 3b,
The reinforcing synthetic resin material filled in 3c is applied to the auxiliary mold surface 3a.
Push it out through the opening.

In the cylinder device 10, a piston lOb provided at the lower end of the rod 10a is arranged in a slidable manner within the first injection hole 3b.

Further, in the cylinder device 11, the piston llb provided at the lower end of the rod 10a that similarly extends from the lower part is connected to the second injection hole 3.
It is arranged so that it can slide inside c.

Each piston 10b, llb of each cylinder device 10.11
The lower end surface of is formed to become a part of the auxiliary mold surface 3a.

Each piston 10b, llb is connected to the cylinder device 1.
The piston 10b rises and falls by the actuation of 0.11, and the respective lowering limits are the piston 10b.

The position where each lower end surface of 11b is flush with the auxiliary mold surface 3a (
(See Figure 1(C)).

Further, although not shown, the vacuum forming apparatus 1 is equipped with a sheet heating heater for heating and softening the sheet-like base material S.

Note that reference numeral 12.12 is a clamp device for fixing both ends of the sheet-like base material S. Further, the pressure and heat resistant hoses 8 and 9 and the auxiliary type 3 may be provided with a heater as necessary.

Next, an example of partially reinforcing the door lining L using the partial wall thickness increasing molding method will be described using the apparatus 1 described in the above embodiment.

However, as the sheet-like base material S used for molding the door lining L, various thermoplastic resins can be used. for example,
It is possible to use a thin plate-like material made by adding filler such as talc or wood flour to polypropylene and formed into a long length with a width matching the height dimension of the door lining L.

Further, as the reinforcing synthetic resin material J, it is possible to use the same material as the sheet-like base material S used in combination, or a material made of an equivalent material.

In FIGS. 1A and 1B, first, the auxiliary mold 3 is pulled up by the vertical movement cylinder 4, and the auxiliary mold surface 3a of the auxiliary mold 3 is sufficiently spaced from the forming surface 2a of the mold 2.

Next, the sheet-like base material S is stretched over the shaping surface 2a of the mold 2 with both ends thereof fixed by clamps 12 and 12.

Then, the sheet-like base material S is heated to approximately 180° C. to 220° C. using a sheet heating heater (not shown) to soften it.

After opening the valve HB with the sheet-like base material S softened by heating to a predetermined temperature, the vacuum pump P is activated to remove the air between the sheet-like base material S and the shaping surface 28 of the mold 2. The air is extracted through a large number of air bleed holes 2b.

At this time, the sheet-like base material S softened by heating is
As the air between them is sucked, both ends are clamped 12.
12, the central part is not stretched but is pulled toward the shaping surface 2a, and first comes into close contact with the shallow part of the shaping surface 2a.

When it is further sucked, the sheet-like base material S is stretched and adheres to the deeper parts one by one. And finally, shaping surface 2
It is attracted to the inner surfaces of the armrest part FA and the shoulder part FS, which are the deep recesses of a, and comes into close contact with the entire shaping surface 2a.

Therefore, the heat-softened sheet-like base material S has the maximum elongation rate in the armrest part FA of the shaping surface 2a, which is a deep concave part, and the part in close contact with the shoulder part FS, and the thickness of these image parts is the highest. It becomes thinner and has the weakest strength.

At this time, the reinforcing synthetic resin material J is put into the hopper section 6 of the resin material supply device 5, and the heater 6a is heated.

70 etc. to give fluidity by heating and melting in advance.

Then, the auxiliary mold 3 is lowered by the vertical movement cylinder 4, and a gap of an appropriate distance is formed between the auxiliary mold surface 3a and the surface of the sheet-like base material S that is in close contact with the shaping surface 2a.

In the gap between the two, that is, the gap between the auxiliary mold surface 3a and the surface of the sheet-like base material S, the reinforcing synthetic resin material J is formed to be thicker as the distance increases.

Moreover, if the amount of reinforcing synthetic resin material J filled into each injection hole 3b, 3c is constant, if the gap is increased,
Although it is formed thicker, the reinforcement range is narrower.

At this time, the amount of reinforcing synthetic resin J filled into each injection hole 3b, 3c at one time is set to 1 shot, and this 1 shot amount is set in advance from the relationship between the thickness and the reinforcement range. Ru.

Then, the reinforcing synthetic resin material J for the set l shots is
is injected into each injection hole 3b, 3c, the valve device 8a,
9a automatically closes to control the filling amount (see FIG. 1(A) above).

In this way, by driving the screw 7a of the resin material supply device 5, the reinforcing synthetic resin material J in the cylinder portion 7 is transferred to the discharge hole 7b.
From there, it is sent to the first injection hole 3b and injection hole 3c via the pressure and heat resistant ports 8 and 9.

Next, the injection cylinder 10.11 is actuated to lower the pistons 10b and llb, respectively.

When each piston 10b, llb descends, each injection hole 3b
, 3c is pushed downward and extruded from the opening of the auxiliary mold surface 3a, which is the lower end of each injection hole 3b', 3c.

Reinforcing synthetic resin material J extruded from the opening of the auxiliary mold surface 3a
is press-fitted into the gap between the auxiliary mold surface 3a and the surface of the sheet-like base material S that is in close contact with the shaping surface.

At this time, the temperature of the reinforcing synthetic resin material J press-fitted into the gap is preferably about 20°C higher than that of the sheet-like base material S, which is softened by heating to about 180°C to 200°C.

When each piston iob, tib reaches its lower limit, one shot of reinforcing synthetic resin material J is press-fitted into the gap and spreads over the area to be reinforced to a predetermined thickness.

At this time, the reinforcing synthetic resin material J is extruded into the gap at a slightly higher temperature or approximately the same temperature than the sheet-like base material S, so it easily adapts to the surface of the sheet-like base material S and is press-fitted. There are no air pockets, and they fit tightly together.

Also, both pistons 10b that push out the reinforcing synthetic resin material J,
At the lower limit, each tip surface of Llb continues flush with the auxiliary mold surface 3a.

Therefore, no protrusion or recess is formed in the press-fitted reinforcing synthetic resin material J facing the opening position of the auxiliary mold surface 3a, and the reinforcement wall thickness can be increased to a predetermined thickness.

Then, while maintaining the above state, the sheet-like base material S, whose thickness has been partially increased, is cooled and solidified by cooling air or the like (see FIG. 1(B) above).

Although not shown, once the sheet-like base material S has solidified, it is trimmed. After that, first, the vacuum pump P is stopped and the valve HB is closed. Then, after opening the valve HB 2, the near compressor C is driven to blow air into the numerous air vent holes 2b through the pipe H. Due to the blown air, the trimmed sheet-like base material S is demolded from the forming surface 2a of the mold 2, resulting in a door lining L (FIG. 1(D)) which is a partially reinforced completed part. ) is obtained.

Further, FIG. 2 shows a pressure forming apparatus for performing a partial thickness increasing forming method according to a second embodiment.

While the vacuum forming apparatus of the first embodiment is equipped with piping equipped with a vacuum pump or the like below the mold, this pressure forming apparatus is equipped with a compressed air box that covers the upper part of the mold. Hereinafter, the same components as in the first embodiment will be denoted by the same reference numerals, and detailed explanation thereof will be omitted.

The air pressure forming apparatus 21 includes a mold (female mold) 2 placed and fixed on a substantially horizontal base B, and an auxiliary mold 3 disposed above the mold 2.

The auxiliary mold 3 is driven in the vertical direction by a cylinder device 4 for vertical movement.

A shaping surface 2a is formed on the upper surface of this mold 2, and an auxiliary mold 30? On the lower surface, there is an auxiliary mold surface 3 shaped to match the shaping surface 2a.
a is formed. By aligning the mold surfaces in this way, the molding surface can be expressed more sharply.

In this example, the auxiliary mold surface 3a was formed to match the mold 2, but in pressure molding, it is not necessarily necessary to match the mold.

Further, the mold 2 is formed with an air vent hole 2b that penetrates from the shaping surface 2a to the lower surface, and the lower end of the air vent hole 2b is exposed to the atmosphere through the opening of the base B.

On the other hand, the auxiliary mold 3 has a first injection hole 3b and a second injection hole 3c.
and a re-injection hole 3b.

The lower end of 3C is open to the auxiliary mold surface 3a which faces the part where the wall thickness is to be increased. A large number of small holes (not shown) are formed in the auxiliary mold surface 3a.

The auxiliary type 3 is connected to a pipe CH equipped with a near compressor C that sends high-pressure air, and the pipe CH is provided with an atmosphere release valve CB.

Then, high-pressure air is sent through the holes in the auxiliary mold surface 3a and pressed against the mold surface.

Further, on the upper surface 3d of the auxiliary mold 3, there is a resin material supplying device 5 for filling the reinforcing synthetic resin material J into both the injection holes 3b and 3c, and a reinforcing synthetic resin material J in the re-injection holes 3b and 3c, respectively. Extrusion injection cylinders to, ii are installed.

The base ends of pressure- and heat-resistant hoses 8 and 9 are connected to the discharge hole 7b of the cylinder portion 7 of the resin material supply device 5, and the tip of one pressure- and heat-resistant hose 8 is connected to the inner upper part of the first injection hole 3b, and the other The tip of the pressure- and heat-resistant hose 9 is connected to the inner upper part of the second injection hole 3C.

Above the shaping surface 2a formed on the mold 2,
A compressed air box 22 is provided.

This compressed air box 22 is vertically driven together with the auxiliary mold 3 by the vertically moving cylinder 4, and when lowered, the lower end peripheral edge 22a is brought into close contact with the sheet-like base material S on the shaping surface 2a so as to airtightly cover it. It has become.

The partial wall thickness increasing molding method performed using the pressure forming apparatus 21 configured as described above is different from that in the first embodiment in that the vacuum forming method and the pressure forming method are different. A sheet-like base material S brought into close contact with the shaping surface 2a by a molding method,
The step of press-fitting the reinforcing synthetic resin material J into the gap with the auxiliary mold surface 3a to partially increase the wall thickness is performed in the same manner.

In addition, in the second embodiment, if a groove or a protrusion is formed near the part where the thickness of the auxiliary mold surface 3a is increased,
Simple-shaped reinforcing ribs and the like can be formed at the same time in the thickened portion.

[Effects of the Invention] As explained above, according to the present invention, partial wall thickness can be easily and reliably increased.

Furthermore, the reinforcement range can be easily expanded or reduced.

Furthermore, it becomes possible to fully automate the molding work, and has the effect of achieving uniformity of products.

[Brief explanation of drawings]

FIGS. 1(A), (B), (C), and (D) show the first embodiment of the present invention, and FIG. 1(A) shows a sheet-like material formed by the vacuum forming apparatus according to the present embodiment. A cross-sectional view showing the process of bringing the base material into close contact with the imprinting surface and the process of filling the injection hole with reinforcing synthetic resin material, Figure 1 CB) shows the synthetic resin material in the injection hole as a sheet-like base material. A cross-sectional view showing the process of forming a thick reinforcing part by injecting it into the gap with the auxiliary mold, Figure 1 (
C) is an enlarged partial sectional view showing the relationship between the shape of the auxiliary mold surface and the tip shape of the piston, FIG. 1(D) is a sectional view showing the door lining of the completed product, and FIG. 2 is the present invention the second of
A sectional view showing a pressure forming apparatus according to an embodiment, and FIG. 3 is a sectional view showing a conventional example. 1... Vacuum forming device, 2...
Molding mold, 2a... Shaping surface, 3...
...Auxiliary type, 3a...Auxiliary type surface, 3b...
...First injection hole, 3C...Second injection hole, 5...Resin material supply device, 10.11...Injection cylinder, P...・・・
・Vacuum pump, C...Near compressor, S...Sheet-like base material, J...Synthetic resin material for reinforcement, Patent applicant Tokyo Sheet Co., Ltd. Agent Patent attorney Atsushi Akiyama (Cause (A)
) Straw 2 diagram procedure? F-original letter (spontaneous) Date: 75th month, 1986

Claims (2)

[Claims] (1) In a vacuum or pressure forming method using a mold and an auxiliary mold, a step of bringing a heat-softened sheet-like base material into close contact with the shaping surface of the mold by vacuum or pressure, and shaping the mold. forming a predetermined gap between the surface of the sheet-like base material that is in close contact with the surface and the auxiliary mold surface of the auxiliary mold;
A step of discharging a predetermined amount of heat-softened resin material from an injection hole opened at a predetermined position on the auxiliary mold surface of the auxiliary mold and press-fitting it into the gap, A method for forming a partial increase in wall thickness in vacuum forming or pressure forming, which is characterized in that forming is performed by partially increasing the wall thickness. (2) A mold with a shaping surface, an auxiliary mold surface whose shape matches at least a portion of the shape of the shaping surface, and an injection hole that opens at a predetermined position on the auxiliary mold surface that matches the shape of the shaping surface. A resin material supply device that heats and melts the resin material and fills it into the injection hole, and an extrusion device that extrudes the resin material filled in the injection hole from an opening in the surface of the auxiliary mold. A forming device for partially increasing wall thickness in vacuum forming or pressure forming.