JP5198336B2 - Resin injection molding method - Google Patents

Description

  The present invention relates to a resin injection molding method, and more particularly to a technique for improving the quality of a molded product in a resin transfer molding (hereinafter referred to as RTM) molding method.

  Conventionally, an RTM molding method has been used to mold resin products such as fiber reinforced plastics (hereinafter referred to as FRP) used for structural members and parts of vehicles and the like (for example, patents). Literature 1, Patent Literature 2). In the RTM molding method, a base material, which is a reinforcing fiber, is placed in a mold, a thermosetting resin is injected into the mold and impregnated in the base material, and then heat-cured to obtain a composite molding material. Is the method.

JP-A-8-323870 JP 2005-271551 A

  According to the technique described in Patent Document 1, a thermosetting resin is injected after a substrate is placed in a closed mold. For this reason, in order to increase the injection speed of the resin, it is necessary to increase the injection pressure after lowering the viscosity of the resin, but this may disturb the arrangement of the base material or wrinkles the surface of the molded product was there.

  Further, according to the technique described in Patent Document 2, the base material and the resin are put into the open molding space, and the resin is developed on the surface of the base material in the molding cavity in accordance with the mold closing, and the subsequent mold The substrate is impregnated with the resin by closing. However, since there is a gap between the mold and the base material, the base material containing the resin may be pushed and moved by the mold. Further, the resin is pushed out to the periphery by such movement of the base material, and fiber disturbance may occur in the part of the base material that does not contain the resin. Furthermore, if the resin is injected under atmospheric pressure, bubbles may enter the base material soaked in the resin, and it is difficult to remove the bubbles even if the molding cavity is in a negative pressure state. there were.

  Therefore, in view of the above situation, the present invention can improve the quality of a molded product by preventing the movement of the base material and the surface of the molded product from wrinkling without lowering the resin injection speed during RTM molding. The present invention provides a resin injection molding method.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, according to the first aspect, the fixed mold, the movable mold arranged to face the fixed mold and configured to be able to approach and separate from the fixed mold, and the position of the movable mold with respect to the fixed mold are set. A resin injection molding method performed by a resin injection molding apparatus comprising: a control device for controlling; and a resin injection device for injecting resin in a state where a base material is disposed between the fixed mold and the movable mold, The base material is disposed on a stationary mold, and after the base material placing process, the distance between the movable mold and the stationary mold is smaller than the apparent thickness of the base material in the atmosphere, and The movable mold is brought close to the fixed mold until it becomes larger than a molding thickness set in advance, and after the proximity process, between the fixed mold and the movable mold by the resin injection device Injecting resin into the resin injecting step, After fat injection process, the distance between the movable die and the stationary die is the until the molding thickness is close to the movable die for molding the molded product, those comprising a molding step.

  3. The resin injection molding apparatus according to claim 2, wherein the movable mold and the fixed mold are disposed in at least one of the fixed mold and the movable mold when the movable mold approaches the fixed mold. A seal structure that abuts against the movable mold side or the fixed mold side facing each other before the abutment, and maintains an airtight state between the fixed mold and the movable mold, and the fixed mold and the movable mold by the seal structure A pressure reducing device for reducing the pressure between the fixed mold and the movable mold while the airtight state between the molds is maintained, and in the proximity step, the movable mold is brought close to the fixed mold, By bringing the seal structure into contact with the movable mold side or the fixed mold side, the space between the fixed mold and the movable mold is brought into an airtight state, and the pressure reducing device is disposed after the proximity process and before the resin injection process. To reduce the space between the fixed mold and the movable mold. To, those with a vacuum process.

  In Claim 3, the said base material is comprised with a fiber material, and the apparent thickness in the air | atmosphere of the said base material is 1.4 times or more of the said shaping | molding thickness set beforehand, Comprising: The said proximity | contact In the step, the movable mold is brought close to the fixed mold until a fiber volume ratio of the base material to a space formed between the movable mold and the fixed mold becomes 35% or more.

  In Claim 4, the said base material is comprised with the fiber material, and the apparent thickness in the air | atmosphere of the said base material exists in the range of 3.7 mm-4.1 mm, and the said shaping | molding preset The thickness is in the range of 2.5 mm to 2.9 mm, and in the proximity step, the fiber volume ratio of the base material to the space formed between the movable mold and the fixed mold is 35%. Until the above, the movable mold is brought close to the fixed mold.

  As effects of the present invention, the following effects can be obtained.

  According to the present invention, the quality of a molded product can be improved by preventing the movement of the base material and the surface of the molded product from wrinkling without lowering the resin injection rate during RTM molding.

Schematic which showed the resin injection molding apparatus which performs the resin injection molding method which concerns on this invention. The figure shown about the flowchart of the resin injection molding method which concerns on this invention. The figure shown about the base material arrangement | positioning process in the resin injection molding method which concerns on this invention. The figure similarly shown about the proximity | contact process. The figure similarly shown about the pressure reduction process. The figure similarly shown about the resin injection | pouring process. The figure similarly shown about the formation process.

Next, embodiments of the invention will be described.
It should be noted that the technical scope of the present invention is not limited to the following examples, but broadly covers the entire scope of the technical idea that the present invention truly intends, as will be apparent from the matters described in the present specification and drawings. It extends.

[Resin injection molding apparatus 10]
First, a resin injection molding apparatus that performs the resin injection molding method according to the present invention will be described with reference to FIG.
As shown in FIG. 1, a resin injection molding apparatus 10 that performs RTM molding is arranged so as to face a metal fixed mold 11 and the fixed mold 11, and can be moved close to and away from the fixed mold 11. And a control device 21 for controlling the position of the movable mold 12 with respect to the fixed mold 11.

  Specifically, the fixed mold 11 and the movable mold 12 are arranged in a press machine, and an actuator 22 composed of an electric cylinder or the like is connected to the movable mold 12, and the actuator 22 is a control device 21. Are electrically connected to each other. The actuator 22 is configured to move the movable mold 12 close to and away from the fixed mold 11 based on a control signal sent from the control device 21. That is, the control device 21 translates the movable mold 12 so as to be close to and away from the fixed mold 11 via the actuator 22 or stops the movable mold 12 with respect to the fixed mold 11. Is controlled.

In the present embodiment, as shown in FIG. 1, the fixed mold 11 and the movable mold 12 are formed in a flat plate shape with protruding peripheral edges, and are arranged so that the protruding peripheral edges face each other. Yes. A cavity is formed between the fixed mold 11 and the movable mold 12 when the movable mold 12 approaches the fixed mold 11 and the respective peripheral edge portions contact each other as shown in FIG. It is.
The shape of the fixed mold 11 and the movable mold 12, that is, the shape of the cavity, which is a space formed between the fixed mold 11 and the movable mold 12 when they abut, is a resin injection molding method. It can be formed corresponding to the shape of the molded product to be molded with, and is not limited to the shape of this embodiment.

  Further, the resin injection molding apparatus 10 is disposed in the movable mold 12 and before the movable mold 12 and the fixed mold 11 come into contact with each other when the movable mold 12 approaches the fixed mold 11. A seal member 15 is provided as a seal structure that contacts the fixed mold 11 and maintains an airtight state between the fixed mold 11 and the movable mold 12.

  Specifically, an annular seal member 15 formed of an elastic material such as a synthetic resin is disposed so as to protrude toward the stationary mold 11 along the peripheral edge of the movable mold 12. As shown in FIG. 4, when the movable mold 12 is close to the fixed mold 11, the seal member 15 is attached to the fixed mold 11 before the movable mold 12 contacts the fixed mold 11. It abuts on the peripheral edge. With the seal structure configured as described above, it is possible to maintain an airtight state between the fixed mold 11 and the movable mold 12 even before the movable mold 12 comes into contact with the fixed mold 11. It is. The seal member 15 may be arranged on the fixed mold 11 or on both the movable mold 12 and the fixed mold 11, that is, at least one of the movable mold 12 and the fixed mold 11. Any configuration may be used as long as it is arranged on one side.

  Further, the resin injection molding apparatus 10 reduces the pressure between the fixed mold 11 and the movable mold 12 while the sealing member 15 is maintaining the airtight state between the fixed mold 11 and the movable mold 12. A pressure reducing device 31 is provided.

  Specifically, the movable mold 12 is provided with a suction port portion 17, and the suction port portion 17 communicates with a decompression device 31 constituted by a suction pump or the like. Then, as shown in FIG. 5, the pressure reducing device 31 is in a state where the seal member 15 is in contact with the peripheral edge of the fixed mold 11 and the airtight state between the fixed mold 11 and the movable mold 12 is maintained. The pressure between the fixed mold 11 and the movable mold 12 is reduced by sucking the air between the fixed mold 11 and the movable mold 12.

  In addition, the resin injection molding apparatus 10 includes a resin injection apparatus 41 that injects a resin between the fixed mold 11 and the movable mold 12.

Specifically, the movable mold 12 is provided with a resin injection port portion 18 provided with a valve 19, and the resin injection port portion 18 is a resin injection device filled with a thermosetting resin. It communicates with the device 41. The resin is, for example, an epoxy resin, and is degassed before being injected. Then, after the pressure between the fixed mold 11 and the movable mold 12 is reduced, the valve 19 is opened, and resin is injected between the fixed mold 11 and the movable mold 12 from the resin injection device 41 as shown in FIG. It is configured as follows.
In the resin injection molding apparatus 10, when molding a resin product composed of a composite molding material such as FRP, a fiber material or the like is provided between the fixed mold 11 and the movable mold 12 (inside the mold) as will be described later. The resin is injected into the mold in a state where the base material P constituted by is placed.
In addition, it is also possible to employ a configuration in which a resin discharge port is opened in one of the movable mold 12 and the fixed mold 11 and excess resin is discharged from the resin discharge port.

[Resin injection molding method]
A resin injection molding method performed by the resin injection molding apparatus 10 configured as described above will be described with reference to FIGS. 3 and subsequent figures, the control device 21, the actuator 22, the decompression device 31, and the resin injection device 41 are not shown.
As shown in FIG. 2, the resin injection molding method according to the present invention includes a base material placement step (step S1) in which a base material P is placed on the fixed die 11, and the movable die 12 after the base material placement step. The movable mold 12 is fixed to the fixed mold 11 until the distance H1 from the fixed mold 11 is smaller than the apparent thickness Hp of the base material P in the atmosphere and larger than a preset molding thickness Hm. And the proximity mold (step S2) for making the space between the fixed mold 11 and the movable mold 12 airtight, and after the proximity process, the decompression device 31 is used to connect the fixed mold 11 and the movable mold 12 to each other. A pressure reducing step (step S3) for reducing the pressure, and a resin injecting step (step S4) for injecting a resin between the fixed mold 11 and the movable mold 12 by the resin injection device 41 after the pressure reducing process. After the resin injection step, Serial spacing H1 between the movable mold 12 and the fixed mold 11, the until the molding thickness Hm is close to the movable mold 12 for molding the molded product, comprising a forming step (step S5), and the.

The above-described resin injection molding method will be described in detail for each step.
In the resin injection molding method according to the present invention, first, as shown in FIG. 3, the base material P is placed in the portion where the cavity is formed in the fixed mold 11 (base material placement step / step S <b> 1). The base material P is an aggregate of high-strength and high-modulus fibers (for example, high-strength carbon fibers of an orthogonal biaxial cloth) that function as a reinforcing material such as FRP that is a molded product. It is formed so as to be impregnated with a curable resin.

  Moreover, since the base material P is an aggregate of fibers as described above, the apparent thickness Hp in the atmosphere shown in FIG. 3 is larger than a preset molding thickness Hm (see FIG. 7). . In other words, the base material P is pressed between the fixed mold 11 and the movable mold 12 as will be described later, so that the apparent thickness Hp in the atmosphere is reduced in the proximity direction of the movable mold 12. As a result, the molding is finally performed so as to have a preset molding thickness Hm.

Next, as shown in FIG. 4, the distance H1 between the movable mold 12 and the fixed mold 11 is smaller than the apparent thickness Hp of the base material P in the atmosphere, and the molding thickness Hm is set in advance. The movable mold 12 is brought close to the fixed mold 11 until it becomes larger (proximity step / step S2). That is, the control device 21 controls the position of the movable mold 12 with respect to the fixed mold 11 and translates the movable mold 12 in the direction of arrow A in FIG. Is stopped at a position where the interval H1 falls within the above range. Here, since the interval H1 is smaller than the apparent thickness Hp, the movable mold 12 comes into contact with the substrate P. That is, the base material P is pressed between the fixed mold 11 and the movable mold 12, and the thickness is reduced in the proximity direction of the movable mold 12 from the apparent thickness Hp in the atmosphere. And the width H1 between the fixed mold 11 and the fixed mold 11.
At this time, as shown in FIG. 4, the seal member 15 contacts the peripheral edge of the fixed mold 11, so that the space between the fixed mold 11 and the movable mold 12 is airtight.

In addition, as shown in the experiment result of the applicant of the present invention described later, the apparent thickness of the base material P in the atmosphere is in a range of 3.7 mm to 4.1 mm, and a preset molding thickness is set. When it is within the range of 2.5 mm to 2.9 mm, in this step, the fiber volume ratio to the space formed between the movable mold 12 and the fixed mold 11 of the substrate P is 35% or more. Until this occurs, it is desirable that the movable mold 12 be brought close to the fixed mold 11. However, the optimal fiber volume ratio varies depending on the type of the substrate P and the size of the molded product.
In the above case, since the fiber volume ratio is about 55% when the distance H1 between the movable mold 12 and the fixed mold 11 reaches a preset molding thickness Hm, in this step It is not desirable to bring the movable mold 12 close to the fixed mold 11 until the fiber volume ratio is about 55%.

  Next, as shown in FIG. 5, the pressure reducing device 31 reduces the pressure between the fixed mold 11 and the movable mold 12 (pressure reducing step / step S3). That is, the air between the fixed mold 11 and the movable mold 12 is sucked in the direction of the arrow B in FIG. At this time, since the sealing member 15 is airtight between the fixed mold 11 and the movable mold 12 as described above, the space between the fixed mold 11 and the movable mold 12 is substantially vacuum.

  Next, as shown in FIG. 6, a resin is injected between the fixed mold 11 and the movable mold 12 by the resin injection device 41 (resin injection step, step S4). That is, as described above, by opening the valve 19 provided in the resin injection port portion 18, the thermosetting resin filled in the resin injection device 41 is placed between the fixed mold 11 and the movable mold 12, that is, It is injected in the direction of arrow C in FIG. Here, the temperature of the resin and the fixed mold 11 and the movable mold 12 is set so that the resin can flow around and inside the substrate P.

In FIGS. 6 and 7, in the base material P, the darkly shaded portion indicates the portion impregnated with the resin, and the darkly shaded portion indicates the portion not impregnated with the resin.
In this embodiment, since the fixed mold 11 and the movable mold 12 are in a substantially vacuum state as described above, the resin is sucked between the fixed mold 11 and the movable mold 12 by negative pressure. The Further, at the time of injecting the resin, the thickness of the base material P is the distance H1 between the movable mold 12 and the fixed mold 11 and larger than the molding thickness Hm, and the fiber density of the base material P is higher than that after molding. Since it is low, the flow resistance of the resin can be reduced, and the resin can be quickly injected between the fixed mold 11 and the movable mold 12.
Further, since the space between the fixed mold 11 and the movable mold 12 is in a substantially vacuum state, bubbles do not enter the inside of the base material P soaked with resin.

  Further, as described above, the base material P is pressed between the fixed mold 11 and the movable mold 12 and is disposed with a reduced width in the proximity direction of the movable mold 12. That is, a frictional force acts between the base P and the fixed mold 11 and the movable mold 12, and the degree of freedom of the base P in the direction perpendicular to the proximity direction of the movable mold 12 is restricted. -ing For this reason, even when the resin is quickly injected as in the present embodiment, it is possible to prevent the base material P from moving or the arrangement from being disturbed.

Next, as shown in FIG. 7, the movable mold 12 is brought close to each other until the distance H1 between the movable mold 12 and the fixed mold 11 reaches the molding thickness Hm (molding process / step). S5). That is, when the movable mold 12 approaches in the direction of arrow D in FIG. 7, the substrate P is compressed, and at the same time, the resin is formed between the fixed mold 11 and the movable mold 12. It is spread throughout and uniformly within.
At this time, since the resin has already spread over a wide portion of the base material P in the resin injection step, the flow resistance for spreading the whole in the cavity can be reduced. Moreover, since the base material P is not pushed by a large flow resistance, it becomes possible to prevent the generation of wrinkles in the molded product.
Thereafter, the temperature of the resin injection molding device 10 is increased by an overheating device (not shown), or the resin is cured at the same temperature and then the movable mold 12 is separated from the fixed mold 11 and the molded product is taken out. is there.

  According to the resin injection molding method of the present invention, by configuring as described above, it is possible to prevent the movement of the base material P and the surface of the molded product from wrinkling without lowering the resin injection speed during RTM molding. Thus, the quality of the molded product can be improved.

  Specifically, the base material P is sandwiched between the fixed mold 11 and the movable mold 12, and the degree of freedom of the base material P in the direction orthogonal to the proximity direction of the movable mold 12 is regulated. Thus, even when the resin is quickly injected as in the present embodiment, it is possible to prevent the base material P from moving or the arrangement from being disturbed.

  In addition, since the resin can be spread over a wide portion of the base material P during the resin injection process, the flow resistance for spreading the whole in the cavity can be reduced, and the fiber disturbance in the base material P can be reduced. It is possible to prevent the generation of wrinkles in the molded product.

  In the resin injection step, the resin injection device 41 is constituted by an injection machine, and the resin is injected between the fixed mold 11 and the movable mold 12 by injecting the resin with the injection machine. It is also possible to adopt a configuration to do so. In this case, the resin can be injected between the fixed mold 11 and the movable mold 12 even if the space between the fixed mold 11 and the movable mold 12 is not substantially in a vacuum state. .

In addition, in the resin injecting step, the space between the fixed mold 11 and the movable mold 12 is set in a substantially vacuum state, and the width of the base material P is set as an interval H1 between the movable mold 12 and the fixed mold 11 to form a molding thickness Hm. In the case of larger than that, the resin can be quickly injected between the fixed mold 11 and the movable mold 12, and air bubbles can be prevented from entering the base material P infiltrated with the resin. .
Further, since the resin is easily impregnated into the substrate P, it is not necessary to increase the number of resin injection ports in order to facilitate the resin impregnation.

[Experimental result]
Next, the experimental results conducted by the applicant of the present application for the resin injection molding method according to the present invention will be described.
In this experiment, in the above-described resin injection molding method, an experimental object (that is, a base material P) in which the apparent thickness Hp in the atmosphere is 3.9 mm and a preset molding thickness Hm is 2.7 mm (that is, the base material). In the case where the distance H1 between the movable mold 12 and the fixed mold 11 is set to 3.8 mm for an experimental object in which the apparent thickness Hp of P in the atmosphere is 1.4 times or more the molding thickness Hm (see above) The fiber volume ratio with respect to the space formed between the movable mold 12 and the fixed mold 11 of the base material P is about 35%, and when the distance H1 is 4.5 mm (also the fiber volume ratio is About 25%) was conducted under the same procedure and conditions.

As a result, when the distance H1 was 3.8 mm, no wrinkles occurred on the surface of the molded product, whereas when the distance H1 was 4.5 mm, wrinkles occurred on the surface of the molded product.
That is, in the proximity process, the distance H1 between the movable mold 12 and the fixed mold 11 is smaller than the apparent thickness Hp = 3.9 mm of the base material P in the atmosphere, and a preset molding thickness Hm = 2. The movable mold 12 was brought close to the fixed mold 11 until H1 = 3.8 mm, which was larger than 0.7 mm (until the fiber volume ratio was about 35%), and the resin was injected between the fixed mold 11 and the movable mold 12. As a result, wrinkles on the surface of the molded product can be prevented, and the quality of the molded product has been successfully improved.
In other words, by carrying out the resin injection molding method according to the present invention, it is possible to prevent the movement of the substrate P and the surface of the molded product from wrinkling without lowering the resin injection speed during RTM molding. It was confirmed that the quality of the product was improved.

DESCRIPTION OF SYMBOLS 10 Resin injection molding apparatus 11 Fixed type 12 Movable type 15 Seal member 21 Control apparatus 31 Pressure reduction apparatus 41 Resin injection apparatus

Claims (4)

Fixed type,
A movable mold that is arranged to face the fixed mold and is configured to be able to approach and separate from the fixed mold;
A control device for controlling the position of the movable mold with respect to the fixed mold;
A resin injection molding method performed by a resin injection molding apparatus comprising: a resin injection device that injects a resin in a state where a base material is disposed between the fixed mold and the movable mold;
A base material placement step of placing the base material on the fixed mold;
After the base material arranging step, until the distance between the movable mold and the fixed mold is smaller than the apparent thickness of the base material in the atmosphere and larger than the molding thickness of the preset molded product, A proximity process for bringing the movable mold close to the fixed mold;
A resin injection step of injecting a resin between the fixed mold and the movable mold by the resin injection device after the proximity step;
After the resin injection step, a molding step is performed in which the movable mold is brought close to the molding until the distance between the movable mold and the fixed mold reaches the molding thickness, and a molded product is formed.
A resin injection molding method. In the resin injection molding device,
The movable mold is disposed on at least one of the fixed mold and the movable mold, and the movable mold is opposed to the movable mold when the movable mold approaches the fixed mold before the movable mold and the fixed mold come into contact with each other. A seal structure that contacts the fixed mold side and maintains an airtight state between the fixed mold and the movable mold;
A pressure reducing device that reduces the pressure between the fixed mold and the movable mold while the airtight state between the fixed mold and the movable mold is maintained by the seal structure;
In the proximity step, the movable mold is brought close to the fixed mold, and the seal structure is brought into contact with the movable mold side or the fixed mold side to make an airtight state between the fixed mold and the movable mold,
A pressure reducing step of reducing the pressure between the fixed mold and the movable mold with the pressure reducing device after the proximity step and before the resin injection step;
The resin injection molding method according to claim 1, wherein: The base material is composed of a fiber material,
The apparent thickness of the base material in the atmosphere is at least 1.4 times the preset molding thickness,
In the proximity step, the movable mold is brought close to the fixed mold until a fiber volume ratio is 35% or more with respect to a space formed between the movable mold and the fixed mold of the base material.
The resin injection molding method according to claim 1, wherein the resin injection molding method is characterized by the above. The base material is composed of a fiber material,
The apparent thickness of the base material in the atmosphere is in the range of 3.7 mm to 4.1 mm, and the molding thickness set in advance is in the range of 2.5 mm to 2.9 mm,
In the proximity step, the movable mold is brought close to the fixed mold until a fiber volume ratio is 35% or more with respect to a space formed between the movable mold and the fixed mold of the base material.
The resin injection molding method according to any one of claims 1 to 3, characterized in that:

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