JP3421101B2 - Composite molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite molding apparatus for molding a fiber-reinforced plastic composite without causing shrinkage holes, cracks, voids and the like.

[0002]

2. Description of the Related Art In recent years, fiber reinforced plastic composite materials have been used as materials for aircraft, ships, automobiles or industrial equipment. Is becoming increasingly important.

[0003] As a method of molding a fiber-reinforced plastic composite material, a reinforced fiber cloth (preform) formed into a substantially final part shape using a woven fabric obtained by subjecting a three-dimensional woven fabric or a two-dimensional woven fabric to a stitching process. ) Is set in a mold, and then the molten resin is transferred or injected by vacuum or pressure from the connecting pipe, and then heated and cured to form a composite material. T. M (resin transfer molding) molding methods are known.

This kind of R. T. The M molding method is disclosed in
No. 3,332,627 and in the 6th next-generation industrial base technology symposium (metal / composite material technology) in the three-dimensional textile composite molding technology.

[0005]

SUMMARY OF THE INVENTION The above-mentioned JP-A-4-332 / 1992
The composite material molding means disclosed in Japanese Patent No. 627 discloses a problem caused by the curing properties of a resin (mainly a thermosetting resin) when a molten resin is transferred or injected into a sealing mold and then heated and cured. When a molten resin is cured by being heated at a high temperature, the volatilization component of the resin is gasified or solidified from a liquid.
No effective method has been taken to prevent the occurrence of defects such as voids, sink marks, and cracks that occur inside and outside the molded product based on the volume shrinkage before and after).

In the three-dimensional woven fabric composite molding technique,
In order to prevent sinks and cracks caused by resin shrinkage due to curing shrinkage, heaters are built in the upper, middle and lower parts of the mold,
By giving a temperature difference to the mold, gelation (solidification) is performed from the upper part farther than the post-pressurization, and the resin contracted by curing is replenished from the middle and lower parts by the post-pressurization. In order to provide a temperature difference between the upper, middle and lower parts of the mold, a heater must be embedded in the mold or a large and complicated heating control device that controls the temperature in three stages is required. Since the mold is made of metal, it has high thermal conductivity and the temperature difference of the mold decreases in a short time, so the temperature difference between the upper, middle and lower parts of the mold Will reach the same temperature in a short time. for that reason,
The curing timing of the resin injected into the mold is almost at the same time, and the resin cannot be replenished for the curing shrinkage. Therefore, it is impossible to prevent sinks and cracks caused by the curing shrinkage of the resin.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has a temperature gradient mechanism having a different temperature depending on a part of a mold without incorporating a heater in the mold.
It is an object of the present invention to provide an apparatus for forming a composite material in which the occurrence of voids, sink marks, cracks, and the like generated inside and outside a molded product is prevented.

[0008]

According to the present invention, there is provided an apparatus for molding a composite material, comprising a reinforcing fiber woven fabric disposed in a mold comprising a lower mold and an upper mold via a pair of upper and lower spacers. In a composite molding apparatus for injecting a thermosetting resin into a resin reservoir space provided on one end side and heating and curing the reinforcing fiber woven fabric impregnated with the thermosetting resin to form the lower mold and the lower mold of the mold, The upper mold is provided with a plurality of cooling pipes and a plurality of heat insulating holes, and a coolant having a different cooling effect is caused to flow through the plurality of cooling pipes, thereby forming a temperature gradient mechanism having a different temperature depending on the part of the mold. Features.

The composite material molding apparatus of the present invention is characterized in that the composite material is formed of an aluminum alloy material having an alumite layer provided on the surfaces of a mold and a spacer. Further, the apparatus for forming a composite material according to the present invention is characterized in that the refrigerant is water or a mist of water and air.

[0010]

In the apparatus for molding a composite material according to the present invention, a refrigerant having a different cooling effect flows through a plurality of cooling pipes provided in the lower mold of the mold and a plurality of cooling pipes provided in the upper mold of the mold. By setting the temperature of the mold according to the part, a temperature gradient mechanism with a different temperature is formed in the mold without incorporating a heater in the mold, and the curing shrinkage generated by solidification of the resin is reduced to the low temperature side By replenishment with the molten resin located, voids, sink marks, cracks and the like are prevented from being generated in the molded product, and a high-quality molded product can be molded.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIGS. 1 and 2 show a mold 1 to be incorporated in the composite material forming apparatus of the present invention. The mold 1 has a lower mold 3 having a concave portion 2 and a lower mold 3 having a lower mold 3. Recess 2 provided in
And an upper mold 4 arranged so as to hermetically close. The lower mold 3 and the upper mold 4 of the mold 1 are formed of, for example, a far-infrared radiation material having high heat efficiency for heating and cooling such as an aluminum alloy material having an alumite layer on the surface. The upper mold 4 has a flat plate shape having sufficient rigidity to withstand a high pressure supplied to the concave portion 2 of the lower mold 3, for example, a gas pressure of 25 kgf / cm ² G. And is fixed to the lower mold 3 by fixing means 6 such as bolts to form a sealed molding space between the lower mold 3 and the upper mold 4.

On one side of the lower mold 3 is formed a resin inlet 7 connected to the recess 2 of the lower mold 3, and on the other side, the resin inlet 7 of the lower mold 3 is formed.
Is formed. Resin inlet 7
Are connected to a gas pressurization line 10 via a valve 9 and a resin inflow line 12 via a valve 11,
Is connected to a gas cylinder filled with a pressurized gas such as a nitrogen gas (not shown). The resin inflow line 12 is connected to a thermosetting resin supply source (not shown). The resin outlet 8 provided in the lower mold 3 is connected to a resin outflow line 14 through a valve 13.
Connected to. A resin reservoir space 15 having a triangular cross section is provided on the resin inflow side of the concave portion 2 of the lower mold 3.
A resin reservoir space 16 is provided on the resin outflow side. The resin pool space 15 has a shape diverging in the resin inflow direction, and the resin pool space 16 has a shape diverging in the direction opposite to the resin inflow direction.

On the other hand, a cooling pipe 17, a heat insulating hole 18, a cooling pipe 19, a heat insulating hole 20, and a heat insulating hole 21 are arranged in a portion of the lower die 3 below the concave portion 2 in order from the upstream in the resin flow direction. And the lower mold 3 is divided into six sections A, B, C, D, E and F along the resin flow direction. Water or a mist that is a mixture of water and compressed air flows through the cooling pipe 17, and air flows through the cooling pipe 19. The reason why the refrigerant flowing through the cooling pipes 17 and 19 is water and air is that the difference in the specific heat of the refrigerant is large, the difference in the cooling effect is also large, and a large heat gradient is formed in the mold. is there.
The heat insulating hole 18, the heat insulating hole 20, and the heat insulating hole 21
The heat flowing from the sections 7, 19 and the mold 1 is saved. The diameter of the heat insulating hole is preferably about 1/2 to 1/3 of the thickness of the lower mold. The upper mold 4 is also provided with a cooling pipe 17a through which water or mist passes, a heat insulating hole 18a, a cooling pipe 19a through which air passes, a heat insulating hole 20a, and a heat insulating hole 21a corresponding to the lower mold 3. Also in this case, the diameter of the heat insulating hole is set to about 1/2 to 1/3 of the thickness of the upper die. Thus, the heat insulating holes 18, 18a, the heat insulating holes 20, 20a are spaced apart from each other in the mold.
By providing the heat insulating holes 21 and 21a, one end of the mold 1 can be set to a gelling (solidifying) temperature of the resin, and the other end can be set to a temperature (gelling) at which the molten state of the resin can be maintained. Temperature), thereby forming a temperature gradient mechanism in the mold 1 in which the temperature varies from one end to the other end.

On the other hand, the reinforcing fiber cloth 22 such as a three-dimensional woven fabric
The lower mold 3 is sandwiched between a pair of spacers 23 and 24 made of a far-infrared radiation material made of the same material as the mold.
Is arranged in the concave portion 2. A pair of spacers 23 and 24
Regulates the thickness of the composite material including the reinforcing fiber cloth 22.

In FIG. 2, reference numeral 25 denotes a thermocouple insertion hole provided in the upper die 4, and this thermocouple insertion hole 25 is provided at, for example, about four to six places at an appropriate position of the upper die. A thermocouple (not shown) is mounted in the thermocouple insertion hole 25. Thermocouples measure the temperature of the mold.

Next, the operation will be described.

Prior to molding the composite material, first, the lower mold 3,
A release agent is applied to the upper mold 4 and the spacers 23 and 24.
Then, the reinforcing fiber cloth 22 is sandwiched between the pair of spacers 23 and 24 to which the release agent is applied. The distance between the spacers 23 and 24 is determined by the composite material to be molded.

Next, the reinforcing fiber cloth 22 sandwiched between the spacers 23 and 24 is disposed at a predetermined position in the concave portion 2 of the lower mold 3, and is placed on the lower mold 3 via the elastic packing 5.
The upper mold 4 is placed so as to cover the upper mold 4, and the upper mold 4 and the lower mold 3 are connected and fixed by the fixing means 6. Thereby, the arrangement of the reinforcing fiber cloth 22 in the concave portion is completed.

Next, with the mold 1 in a state in which the valve 9 of the gas pressurizing line 10 is closed, the resin inflow port 7 faces downward,
And the resin outflow line 1
4 is connected to a vacuum device (not shown). Then, by opening the valve 13 provided in the resin outflow line 14, a vacuum is drawn from the resin outlet 8, and the concave portion 2 of the lower mold 3 is brought into a reduced pressure state.

Next, the pressurized thermosetting resin is sent from the resin inlet 7 to the concave portion 2 of the lower mold 3 by opening the valve 11 of the resin inflow line 12, and the heat is applied to the reinforcing fiber cloth 22 arranged in the concave portion 2. Inject the curable resin. Then, the reinforcing fiber cloth 2
Excess resin of the thermosetting resin injected into 2 is discharged from the resin outlet 8 to the outside. Thus, the reinforcing fiber cloth 22 is impregnated with the thermosetting resin.

Next, the valve 1 provided in the resin outflow line 14
3 and the valve 11 of the resin inflow line 12 are closed,
The mold 1 is turned 180 degrees or turned 90 degrees so that the resin inlet 7 is on the upper side and the resin outlet 8 is on the lower side, and is set in a horizontal state. When the setting of the mold is completed, the valve device 9 of the gas pressurizing line 10 is opened, and a pressurized gas such as a nitrogen gas is supplied to the concave portion 2 of the lower mold 3 through the gas pressurizing line 10, and is placed in the concave portion 2. The thermosetting resin injected into the reinforced fiber cloth 22 is directly pressed. The pressure for directly pressing the thermosetting resin injected into the reinforcing fiber cloth 22 is such that the higher the pressure, the more the occurrence of voids, sink marks, cracks and the like generated inside and outside the molded product can be prevented. / cm ² G
At a moderate level of pressure, the intended purpose is fully achieved.

Next, in order to mold the composite material, the mold 1 in which the reinforcing fiber cloth 22 impregnated with the thermosetting resin is disposed in the recess 2 is placed in a heating furnace 30 such as an oven (see FIG. 4). A cooling pipe 17 of the lower mold 3 and a cooling pipe of the upper mold 4 are connected to the cooling pipe 17 of the lower mold 3 and the cooling pipe 17a of the upper mold 4 by connecting a heat-resistant silicon hose (not shown) connected to the mist supply device. A heat-resistant silicone hose (not shown) connected to the compressed air supply device is connected to 19a. This completes the preparation for supplying the refrigerant to the cooling pipe.

Next, a thermocouple is mounted in each of a plurality of thermocouple insertion holes 25 provided in the upper die 4. These thermocouples
The temperatures of the six sections A, B, C, D, E and F defined by the mold are monitored.

Next, in order to form a temperature gradient mechanism in the mold, a mist or water in which air and water are mixed is passed from a mist supply device to a cooling pipe 17 and a cooling pipe 17a. Through the cooling pipe 19 and the cooling pipe 19a. This temperature gradient mechanism is temperature-controlled so that the thermosetting resin is solidified in the six sections A, B, C, D, E, and F, for example, which partition the mold. This temperature control is performed by a controller (not shown) that receives a signal from a thermocouple provided in the upper mold, and solidifies the thermosetting resin in the mold by controlling the temperature of the oven and the flow rate of the cooling refrigerant. . That is, the entire mold 1 is heated in a state where it is cooled by the mist or water mixed with air and water passing through the cooling pipe 17 and the cooling pipe 17a and the compressed air passing through the cooling pipe 19 and the cooling pipe 19a. Since the cooling pipe is provided at an intermediate position between one end of the mold 1 and the mold 1, the mold 1 heated by the heating furnace has a temperature at which one end maintains the thermosetting resin in a molten state (a temperature at which gelling does not occur). It is cooled and heated to a temperature at which the thermosetting resin is gelled (solidified) at the other end.
As a result, a temperature gradient mechanism in which the temperature varies sequentially from one end to the other end is formed in the mold 1. The temperature gradient mechanism of the mold includes the sections E and F cooled by the cooling pipe 17 and the cooling pipe 17a, the sections D and C cooled by the cooling pipe 19 and the cooling pipe 19a, and the sections A and B to be heated. It is formed by a temperature difference. In other words, the temperature gradient mechanism of the mold provides the heat insulating holes 18 and 18a between the area E and the area D, the heat insulating holes 20 and 20a between the area C and the area B, and the area between the area B and the area A. By providing heat insulation holes 21 and 21a, respectively, and determining the diameter of the heat insulation holes, the heat insulation area between the sections can be reduced to 1/2 to 1/3.
To maintain zone A at the gelation temperature by transferring the reduced thermal energy to the adjacent zone,
Is maintained at a temperature in the molten state.

However, the thermosetting resin impregnated in the reinforcing fiber cloth 22 provided in the concave portion 2 by the temperature gradient mechanism formed in the mold and the internal pressure pressurization by the high-pressure gas is first applied to the high-temperature zone A. Is solidified, and the volumetric shrinkage of the thermosetting resin generated due to the solidification of the area A is replenished by the thermosetting resin which is still under the pressure of the high-pressure gas in the area B in a molten state. . Then, the area B is solidified by controlling the refrigerant passing through the cooling pipe. The volume contraction of the thermosetting resin at this time is replenished by the thermosetting resin which is receiving the pressure of the high-pressure gas in the area C which is still in a molten state. Thereafter, the solidification is performed up to the area F while controlling the refrigerant and the heating in order. In the area F, the volumetric shrinkage of the thermosetting resin is replenished by the thermosetting resin stored in the resin reservoir 15.

Further, by the function of the far-infrared radiation member used in the mold, heating to the thermosetting resin is performed by heat conduction and heat radiation (heat radiation). Since the external resin is heated simultaneously (organic resin such as plastic absorbs heat energy well against radiation), the volume shrinkage is found in the center of the molded product, which has been confirmed by conventional heating with only heat conduction. No concentrated defects occur. Further, the presence of the high-pressure gas for pressurizing the resin in the mold suppresses gasification of volatile components contained in the thermosetting resin.

FIG. 4 shows a state in which the mold (A) of the present invention and the conventional mold (B) are arranged in the oven 30 in order to compare the temperature change of each part of the mold when the heat treatment is performed. FIG.

In the mold (A) of the present invention, the mold 1 and the spacers 23, 24 are formed of an aluminum alloy material having an alumite layer on the surface, and the upper mold 4 has a1, a2, a
Thermocouples are arranged at positions 3 and a4.

In the conventional mold (B), molds 1 and 2
The spacers 3 and 24 are made of an aluminum material, and thermocouples are arranged at positions b1, b2, b3 and b4 of the upper die 4.

FIG. 5 shows a temperature record when the mold 10 is heated.

The results of measurement with a thermocouple are shown in the table below.

Table 1 Kim measurement points a ₁ a ₂ a ₃ a ₄ inch Temperature (℃) 61.0 67.5 74.0 77.0 Temperature difference 0 6.5 13.5 16.0 a A a ₁ Kim measurement points b ₁ b ₂ b ₃ b ₄ Type Temperature (℃) 57.5 63.0 67.0 71.5 Temperature difference 0 5.5 9.5 14.0 a B b ₁ As is clear from the measurement results, the mold (A) of the present invention
In comparison with the conventional mold (B), the heat efficiency of heating and heat radiation is about 14% better, and the molding time is shortened.

FIGS. 6 to 8 show another embodiment of the present invention. The mold shown in FIG. 6 is for molding a cylindrical or cylindrical composite material. Except that the internal shape and the spacer are formed following the molded product,
It has the same configuration as the mold shown in FIGS.

The mold 40 shown in FIGS. 7 and 8 is for molding a disc-shaped composite material.
Are the cooling pipes 41 and 42 provided and the heat insulating holes 4
3 differ in position and form.

That is, the mold 40 shown in FIGS.
Here, cooling pipes 41, 41a made of water or mist are arranged at the outermost periphery of the molded article, and cooling pipes 42, 42a made of mist or air are arranged at the center of the molded article. An annular heat insulating hole 43 is arranged in the middle. In this case, the molded product is solidified from the center of the mold, and then solidified on the outer periphery of the molded product, whereby a high-quality molded product is obtained as in FIGS.

[0037]

As described above, according to the present invention, a plurality of cooling pipes and a plurality of heat insulating holes are provided in the lower and upper molds of the mold, and a refrigerant having a different cooling effect is provided in the plurality of cooling pipes. Shed
By forming a temperature gradient mechanism with different temperatures depending on the part of the mold, it is possible to obtain a set temperature and an indicated temperature difference without using a complicated control device for the temperature gradient mechanism. Effective replenishment of resin by shifting the resin solidification timing to prevent voids, sink marks, cracks, etc., occurring inside and outside the molded product, and to obtain a high quality composite material molded product Can be.

Further, since the mold and the spacer are formed of an aluminum alloy material provided with an alumite layer on the surface, the resin inside and outside of the molded product is simultaneously heated by radiating action, thereby obtaining the conventional heat. Concentration of the volume shrinkage at the center of the molded product caused by heating only by conduction is prevented, and a uniform and high-quality molded composite material can be obtained.

Further, gasification of volatile components contained in the resin can be suppressed by the presence of the high-pressure gas for pressurizing the resin in the mold.

[Brief description of the drawings]

FIG. 1 is a plan view showing a cross section of a part of a composite material forming apparatus according to the present invention.

FIG. 2 is a front view showing a cross section of a part of a composite molding apparatus according to the present invention.

FIG. 3 is a side view of a composite molding apparatus according to the present invention.

FIG. 4 is a diagram for comparing a thermal gradient state of a composite material forming apparatus according to the present invention and a conventional composite material forming apparatus.

FIG. 5 is a temperature recording model diagram of a composite material forming apparatus.

FIG. 6 is a view showing another embodiment of the composite material forming apparatus according to the present invention.

FIG. 7 is a plan view showing another embodiment of the composite material forming apparatus according to the present invention.

FIG. 8 is a side view of the composite material forming apparatus of FIG. 7;

[Explanation of symbols]

1 Mold 2 recess 3 lower mold 4 Upper type 6 Fixing means 7 Resin inlet 8 Resin outlet 9 Gas line valve 10 Gas pressurization line 11 Resin inflow line valve 12 Resin inflow line 13 Resin outflow line valve 14 Resin outflow line 15 Resin pool space 16 Resin pool space 17, 17a Cooling pipe 18, 18a Insulation hole 19,19a Cooling pipe 20, 20a Insulation hole 21, 21a Thermal insulation hole 22 Reinforced fiber cloth 23, 24 spacer

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-210644 (JP, A) JP-A-4-339608 (JP, A) JP-A-61-263714 (JP, A) JP-A-61-263 271302 (JP, A) JP-A-5-237858 (JP, A) JP-A-5-192945 (JP, A) JP-A-4-332627 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) B29C 33/38 B29C 33/04 B29C 70/06

Claims (3)

(57) [Claims] 1. A reinforcing fiber cloth is arranged in a mold comprising a lower mold and an upper mold via a pair of upper and lower spacers, and a thermosetting resin is filled in a resin reservoir space provided at one end of the mold. In a molding apparatus of a composite material for injecting and heating and curing the reinforcing fiber cloth impregnated with the thermosetting resin, a plurality of cooling pipes and a plurality of heat insulating holes are provided in a lower mold and an upper mold of a mold. A molding apparatus for a composite material, characterized in that a refrigerant having a different cooling effect is caused to flow through a plurality of cooling pipes to form a temperature gradient mechanism having a different temperature depending on a part of a mold. 2. The composite molding apparatus according to claim 1, wherein the mold and the spacer are formed of an aluminum alloy material having a surface provided with an alumite layer. 3. The composite material molding apparatus according to claim 1, wherein the refrigerant is water or a mist of water and air.