JPH06239295A - Forming method apparatus for composite blade - Google Patents

Abstract

PURPOSE:To lessen remaining bubbles by repeating the process of shutting off an outlet at resin injection discharging surplus resin after a specified time until bubbles are not contained in the discharged resin. CONSTITUTION:In a mold 1 for forming there occurs a portion (path) where resin flows easily and a portion (stagnation) where the flow is difficult, so that pressure difference locally appears within the mold 1. Then by closing an opening/closing valve 8 flow of resin stops and thus there is no pressure difference in the mold 1. Then, by opening the opening/closing valve 8 at a time when the pressure within the mold 1 is possibly uniform, resin in a portion where the flow is easy, flows to lower the pressure, so that resin stagnating in a portion where the flow is difficult is pushed out. Bubbles involved in the stagnant portion are thus discharged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a composite material blade using a resin injection molding method and an apparatus therefor, and in the process of injecting resin and letting excess resin flow out from a discharge port, bubbles are generated in the discharged resin. TECHNICAL FIELD The present invention relates to a method and an apparatus for molding a composite material blade having a high-quality molding layer with few residual bubbles by repeating discharging and blocking for the number of times until no longer contained.

[0002]

2. Description of the Related Art Blades such as aircraft propeller blades, turbofan blades, helicopter blades, and general industrial rotary blades are sometimes made of a composite material such as FRP instead of conventional metal. The method of forming a composite material blade generally includes a mold for forming the ventral surface of the blade and a mold for forming the back surface, and a blade insert having reinforcing fibers attached to the surface thereof is inserted to squeeze the mold, and a thermosetting resin is used. A resin injection molding method is employed in which excess resin is allowed to flow out through a discharge port while being injected, and then heated to a required temperature or held for a required time to solidify the resin and mold the resin.

[0003]

In the conventional resin injection molding method, bubbles were often left in the impregnation of the reinforcing fiber with the resin. The cause is that the density distribution of the reinforcing fibers varies, so that the flow resistance of the resin in the molding die is inconsistent, and there is a portion where the resin easily flows and a portion where the resin hard to flow and stays. . If a part of the resin entrained with air bubbles stays, no matter how much resin is injected and replaced, the new resin will flow through the above-mentioned passage part where the resin easily flows, and it will not be effectively replaced. there were.

An object of the present invention is to provide a method of molding a composite material blade having a high quality molding layer containing few residual bubbles in the method of molding a composite material blade using a resin injection molding method, and an apparatus therefor.

[0005]

According to the present invention, a blade insert having reinforcing fibers attached to the surface thereof is inserted between a mold for molding a ventral surface of a blade and a mold for molding a back surface of the blade, and the mold is squeezed and heat-cured. In the method of molding a composite material blade that uses a resin injection molding method in which excess resin is allowed to flow out of the discharge port while injecting the resin and then solidified, the discharge port is blocked when the resin is injected, and the excess resin is discharged after a predetermined time. The method for forming a composite material blade is characterized in that the step of carrying out is repeated until the discharged resin contains no bubbles.

A second aspect of the present invention is a resin injection molding apparatus comprising a molding die provided with a resin injection port and a discharge port, wherein an opening / closing valve is provided in the conduit between the discharge port and the resin reservoir container, and the resin is injected at the time of resin injection. A composite material blade characterized by having an on-off valve control means for repeating the shut-off and conduction cycle in which the valve is closed and the valve is opened after being held for a predetermined time to discharge excess resin in a pre-programmed step. It is a molding device.

[0007]

The operation of the method for molding a composite material blade according to the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing the structure of a molding apparatus for a composite material blade according to the present invention. Figure 2
FIG. 2 is an AA cross-sectional explanatory view of the molding die of FIG. 1. The molding die 1 of the molding apparatus is provided with a resin injection port 2 and a discharge port 3, and the resin injection port 2 has an injection pipe 5 from a resin pressure feed tank 4.
And the resin reservoir 7 through the conduit 6 to the discharge port 3.
An on-off valve 8 is attached in the middle of the conduit 6, and the on-off valve 8 is controlled by a valve controller 9.

When molding, first, the blade insert 1
The reinforcing fiber 11 is attached to 0, the cavity 1c of the molding die 1 is loaded, and the dies 1a and 1b are closed. The piston 4a of the resin pressure feed tank 4 is pushed down, and the resin in the tank is injected into the molding die 1 from the injection port 2 via the injection pipe 5. The resin flows through the gap between the wall of the cavity 1c and the blade insert 10, but since the gap is filled with the reinforcing fiber 11, the resin slowly flows so as to permeate the reinforcing fiber 11. Due to the variation in the density of the reinforcing fibers 11, the flow resistance of the clearance varies depending on the location in the molding die 1, and a location where the resin easily flows and a location where the resin does not easily flow are formed.

Therefore, even if the injection is continued for a long time, the resin forms a steady passage in a place where the resin easily flows and tends to drift. On the other hand, a place that is difficult to flow forms a steady pool. Further, it is difficult to discharge air bubbles generated in the initial stage of injection when the resin is entrained to form a pool, and if cured as it is, a molded product containing residual air bubbles is obtained. Here, if the opening / closing operation of the opening / closing valve 8 is added, the stabilized flow path distribution can be destroyed, and such a pool is discharged. However, after a while, since it becomes steady again, it is necessary to repeat the opening / closing operation.

That is, the flow of the resin in the molding die 1 constantly has a portion (passage) that easily flows and a portion (pump) that does not easily flow, and a pressure difference locally occurs in the die 1. However, when the on-off valve 8 is closed, the resin flow stops,
The pressure difference in the mold 1 is also eliminated. When the on-off valve 8 is opened in anticipation of the time when the pressure in the mold 1 becomes uniform, the resin in the easy-to-flow portion flows, and the pressure also decreases, so the resin that has accumulated in the difficult-to-flow portion is pushed to the easy-to-flow portion. Air bubbles trapped in the pool are discharged. However, since the flow distribution becomes steady again after it has been flowing for a while, it is possible to break the steady flow passage by closing the opening / closing valve 8 again. The opening / closing valve 8 is opened / closed by the valve controller 9, and the opening / closing interval is appropriately selected according to the molding die, the shape of the material to be molded, the type of resin, and the like.

[0011]

EXAMPLES Using the molding apparatus according to the present invention shown in FIG. 1, a composite material blade was molded using carbon fiber as the reinforcing fiber and epoxy resin as the resin. When the resin is injected, the on-off valve is closed to block the discharge port, and after holding for 5 minutes, the on-off valve is opened to discharge excess resin for 10 minutes, and the on-off valve is closed to inject the resin. This was repeated until no air bubbles were contained in the resin, and then heated and held to cure the resin to complete the molding. Further, when the same composite material blade was formed by a conventional resin injection molding method having no on-off valve in the discharge system, a plurality of bubble traces were found on the blade surface layer portion. On the other hand, in the above-described molding method according to the present invention, there are no bubbles in the surface layer portion, and a high-quality composite material blade is obtained.

[0012]

EFFECT OF THE INVENTION The present invention is a method for molding a composite material blade using a resin injection molding method, in which the resin is injected by repeating the steps of blocking the discharge port at the time of resin injection and discharging the excess resin after a predetermined time. The part that is difficult to flow (accumulation), that is, the steady flow path can be destroyed, and the discharge of bubbles remaining in the mold is promoted until the discharged resin does not contain bubbles, resulting in a shorter molding time and residual bubbles. It is possible to form a composite blade with less
A remarkable effect is obtained in improving the quality of the composite material blade.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a configuration of a molding apparatus for a composite material blade according to the present invention.

FIG. 2 is an AA cross-sectional explanatory view of the molding die of FIG.

[Explanation of symbols]

 1 Mold 1a, 1b Cavity 1c Cavity 2 Injection port 3 Discharge port 4 Resin pressure feed tank 5 Injection pipe 6 Conduit 7 Resin reservoir 8 Open / close valve 9 Valve controller 10 Blade insert 11 Reinforcing fiber

Claims (2)

[Claims] 1. A blade insert having a reinforcing fiber attached to the surface thereof is inserted between a mold for forming a ventral surface of a blade and a mold for forming a back surface of the blade, and the mold is squeezed, while a thermosetting resin is injected to remove excess material. In the molding method of the composite material blade using the resin injection molding method in which the resin is allowed to flow out from the outlet and then solidified, the step of blocking the outlet at the time of resin injection and discharging the excess resin after a predetermined time is changed to the discharged resin. A method for forming a composite material blade, which is repeated until bubbles are not contained. 2. A resin injection molding apparatus comprising a molding die provided with a resin injection port and a discharge port, wherein an opening / closing valve is provided in the conduit between the discharge port and the resin reservoir, and the valve is closed at the time of resin injection. An apparatus for molding a composite material blade, comprising: an opening / closing valve control means for repeating a shutoff / conduction cycle in which the valve is opened after the time is held to discharge excess resin in a preprogrammed step.