JP3168092B2 - Method and apparatus for making preforms - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to resin transfer molding (RTM) and reaction injection molding (SRI) for structural compositions.
M) Methods and apparatus for making structurally reinforced preforms for processing, and more particularly to techniques for making such structurally reinforced preforms by fiber orientation.

[0002]

2. Description of the Related Art In order to prepare a preform by a fiber orientation process, it is common to spray air cut into a mold holding a fiber in a fixed place together with a binder resin into a mold for holding the fiber. is there. Next, the mold holding the fiber and the binder resin is put into a hot air filled chamber (plenum),
Dry or cure to harden the binder resin. This process requires a large processing space for heating, drying, curing and cooling the preform. Therefore, this process also requires a large furnace and other equipment for handling preforms.

[0003] When preparing thermoformed preforms,
It is common to coat a continuous twisted fiber mat with a thermoplastic binder during fabrication. This mat is supplied in roll form. The mat is unwound and provided in a number of overlapping flat sheets to change the thickness of the preform and clamped at the ends into a holding frame. The frame is then placed in a furnace with a radiant heater and the reinforcing mat and thermoplastic binder are slowly heated from both sides. The thermoplastic binder softens in response to heating and transfers the frame into a cold mold while soft. The mold is then operated to press the reinforced mat into the desired shape. Upon cooling, the thermoplastic binder cures and maintains the thermoplastic mat in its new shape.

These processes are slow and require a large space and a large amount of electric power for heating and cooling.

[0005] The flexibility of the design requires the unnecessary use of material in the other area (layering) in order to meet the strength requirements in one area, which adds to the thickness and weight. Restricted. Furthermore, the above process does not allow the designer to add assembly parts such as ribs or closed parts to maximize design characteristics.

[0006] Eliminating the need for large rooms, constantly operating furnaces, cooled presses, etc., the assembly components (reinforced ribs,
New systems have been proposed that provide design flexibility in terms of providing closed parts and attachments and reinforcements, while at the same time saving power and materials.

[0007] These new processes have been specially developed with an irradiation energy system that solidifies the composite shape and attaches the structural components to the preform, using a suitable binder, and using RTM and SRIM resin systems, ie, polyesters. It is completely compatible with vinyl ester, urethane, epoxy, phenolic resin and acrylic resin. These new processes are fully automated and, if necessary, are designed to allow special distribution and installation of various reinforcements, etc., for the structural properties required of the preform. There is complete design freedom inherent in the process of matching the most desirable reinforcement types and structures with closed structural shapes and various wall sections to design criteria.

[0008] In the fiber orientation process, a preform that desires a mat of reinforcing material is cut into a desired shape that is two-dimensionally flattened. The cut mat is then coated with a binder that responds to electromagnetic energy, i.e., micro-radiation or ultraviolet radiation, and the cut mat is placed in a three-dimensional mold and pressed to duplicate a preform of the desired shape. .
The coating covers the fibers to an extent sufficient to cover the fibers without closing the gaps between the fibers. The mat formed in the mold is subjected to the appropriate electromagnetic radiation, ie, microwaves or ultraviolet light, to cure the binder resin, and is cured by heat curing in units of seconds rather than minutes or hours. At this point, the preform is placed in the next molding operation (RTM, SRI).
M) can be considered as a finished product for use in, or as a preform for mounting, such as a structural reinforcement, etc., before use in the next forming operation (RTM, SRIM).

[0009] Assuming that the preform is a preform for mounting, it is transferred from the mold to the station. There, the designated area, or the area of the interior or exterior surface, or the area of the assembly is further coated with an electromagnetic energy curing binder. Move the reinforcing member, etc., in close contact with the preform in the covered area, apply appropriate electromagnetic radiation (microwave or ultraviolet), and fasten this member to the mounting preform (binder Cure). If the final installation is performed with such strong fastening, the preform is itself a finished product and will be structurally reinforced preformed as part of another forming process that creates a structural composite Can be used as goods.

[0010] Unwind and cut individually into the desired shape,
Regarding the processing of the reinforcing material supplied by rollers, which must be loaded into the respective mold storage locations, a binder is applied to the overlapping webs before cutting, and the overlapping webs are pressed to remove the binder and the adjacent web. The binder is cured in locally spaced areas to enhance the surface contact of the fibers and to temporarily hold the web together prior to or during the cutting process, thereby pre- or simultaneously with cutting such layers. At the time of fastening (called strong temporary fastening), the process is simplified,
The fastening is unique.

This technique localizes the tack, first cuts the two-dimensional spread of the desired three-dimensional shape from the tacked web, and then cures to secure the multilayer mat to the desired three-dimensional shape. It has also proven to be effective in that sufficient binder remains.

After the preform has hardened, powerful fastening techniques can still be used to attach assembly parts, such as reinforcing members and mounting members, to the preform.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to apply a radiation energy technique to a basic fiber orientation process to produce a preform having a structure and, at the same time, temporarily fix a mat strongly. SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved fiber orientation process and apparatus which eliminates the need to treat a web of material in a prior art manner, such as by handling or holding a single layer mat.

[0014]

According to the present invention, there is provided, in accordance with the present invention, a porous first mold part and a second mold part for pressing, wherein when both mold parts are closed, It becomes the desired three-dimensional shape of the preform, and it is arranged inclined to each other,
A method for making a preform having a rigid three-dimensional structure using a separable mold having an inner surface forming an inner corner and an outer corner, the method comprising the steps of: The fibers are sprayed on the cut fibers with an electromagnetic energy-curing binder, and the fibers are at least partially covered with the binder without closing the gaps between the fibers, and the cut fibers are partially covered with the binder. To the first mold part, and at the same time, direct the air flow so as to pass through the first mold part. The second mold part is closed, the binder is coated and the cut fibers are pressed, and the fibers bridging the inner corners and the outer corners of the closed mold are closed. The second metal for pressing the closed mold so that it can be transformed into the desired shape determined by the part Forming the desired three-dimensional shape of the preform between the part and the porous first mold part, applying electromagnetic energy to the coated and pressed fibers, curing the binder in the closed mold during that time, This is accomplished by combining the fibers to form a rigid three-dimensional structure preform, opening the mold, and removing the rigid three-dimensional structure preform from the mold.

Further, the object of the present invention is to provide an apparatus for producing a preform having a solid three-dimensional structure according to the present invention, wherein one mold part is complementary to the inner surface of the other mold part. Having an inner surface, both complementary inner surfaces of which duplicate the desired three-dimensional structure of the preform, including any inner and outer corners of the preform, wherein the inner surface of the first mold portion is porous. The first and second molds are materials that support the air flow through this mold part, and that both mold parts are permeable to predetermined electromagnetic radiation at least on the inner surface. A separable mold consisting of parts, means for directing airflow past the first mold part, directing the fibers towards the surface of the first mold part and adhering the entire surface to a predetermined thickness; Cutting means for cutting the reinforcing material into short fibers, and cutting the cut fibers on the first mold part A discharge means for discharging and holding the discharge means therewith in a flow of air passing through the first mold part, a reinforcement material supply section for supplying a reinforcement material, a binder for supplying a binder which hardens in response to the predetermined electromagnetic radiation A source, spray means connected to the binder source and spraying a binder on the cut fibers at least partially by covering the cut fibers without closing gaps between the fibers; fibers bridging the inner corners and the outer corners The binder is coated and the cut fibers are pressed to deform into the desired shape of the corners of the closed mold and separable to form a desired three-dimensional structure preform between both mold parts Means for closing the mold part, means for applying electromagnetic energy to the coated and pressed fibers covering the binder, curing the binder in the closed mold, bonding the fibers and forming a preform having a solid three-dimensional structure, the mold Means to open the hard three It has been solved by comprising the original structure preforms means removed from the mold from.

[0016] Further advantageous configurations according to the invention are set out in the dependent claims.

[0017]

The processing method according to the present invention does not require heated air for subsequent directed energy curing, but assists the flow of air through the mold when placed in the plenum. A porous mold is used.

The reinforcing material is withdrawn from the roving supply on the bobbin, cut, and thrown into a stream of air toward the porous mold section by spraying. The air flow sprays the electromagnetic energy-curing binder into the fibers and at least partially coats the fibers with the binder during movement to the porous mold portion and after the mold reaches its destination. The binder is applied to an extent sufficient to cover the fibers without closing the gaps between the fibers. While adding the fiber and binder, rotate the porous mold section to obtain a complete coverage of the desired thickness of the fiber. The fibers and binder are directed from the end of the robot arm to thicken and flatten the coating. The robot arm is operated in accordance with the program to scan the porous mold section and ensure that all areas including the inner corners are covered.

After the fibers and the binder have been added to the porous mold portion, the mold is closed, a second mold portion having a complementary shape is pressed against the porous mold portion, and the added fibrous shape is added. The mat is pressed into a preform of the desired shape. This is a low pressure pressing operation, which ensures that the fibers bridging the inner and outer corners of the formed mat will deform and conform to the shape of these corners.

While still in the mold, the pressed mat of fibers coated with the binder is irradiated with appropriate electromagnetic radiation (microwave or ultraviolet) to cure the binder and solidify the fibrous mat into a pressed shape. Let it. At this time, the solidified three-dimensional fibrous mat is a preform, which can be transferred to a molding process for producing a structural composite, or can be regarded as a mounting preform having a reinforcing member or the like attached thereto.

If the preform is considered a mounting preform, it is transferred from the mold to a station that applies an electromagnetic energy curing binder to at least one selected surface of the preform or assembly. The assembly, i.e., the reinforcement member, is brought into intimate contact with the preform in the coating area, appropriate electromagnetic energy is applied to the coating area to cure the binder, and the reinforcement member is attached to the preform. This operation is called strong fastening, and it is desired to attach an assembly (reinforcement, fastener, mounting member, etc.) to the preform before moving the preform to a molding process such as an RTM or SRIM process. Occurs many times each time.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the embodiments shown in the drawings. According to FIG. 3, the basic treatment of the oriented fiber and the irradiation energy is performed in five stages consisting of a molding stage 1, an adhesion stage 2, a supply stage 3, a strong fastening stage 4 and an ejection stage 5. It is generally indicated as being performed.

The molding stage 1 (FIG. 1) is a lower first mold part 6 supported by a plenum 7 for rotation. The first mold part 6 is a porous member, and the plenum 7 assists the air flow through this mold and is inclined with respect to each other,
A mat is formed on the surface 8 defining the inner and outer corners. This mold part 6 is complementary to the upper second mold part 10 and both mold parts have complementary inner surfaces which define the desired three-dimensional shape of the preform replicating the preform. .

The mold parts 6 and 10 are parts of a low-pressure stamping mold and comprise, as is known for stamping dies, one or more rams, suitable guides and connections. It is shown as being mechanically coupled to the opening and closing mechanism 12 of the resulting mold. When the mold is opened, short fibers of a reinforcing material, such as a glass fiber reinforced material, and a binder resin that cures in response to the selected electromagnetic radiation are determined by the plenum and the porous mold portion 6, The outside is the airflow (arrow A)
). In order to improve the coating, the mold part 6 is rotated as indicated by the arrow 38, and the fibers and the binder are directed to the mold part 6 by the robot 14 of the adhesion stage 2 via the air flow.

The robot is shown as having a vertical axis and at least two horizontal axes. Therefore, the fibers and the binder emerging from the ends of the arm structures 16 and 18 can be directed to all the portions of the rotatable mold portion 6.

The adhering stage 2 is connected to a robot having arms 16 and 18 and roving yarns 22, 24, 24, via a tube 28 attached to the arm 18 from the roving frame of the supply stage 3.
It is shown as consisting of a cutting machine 20 for receiving 26, a conduit 30 for carrying a binder 32 supplied to a spray nozzle 36 by a pump 34, and an outlet port 28 'for the cut fibers.

The supply stage 3 is shown as comprising a plurality of bobbins of rovings 22, 24, 26 of reinforcement material to be supplied to the tube 28, a supply of binder 32 and a pump 34.

The cutter 20 pulls and cuts the roving yarns 22-26, and includes one or more gears and cutting blades for throwing the cut fibers into the air stream toward the porous mold part 6. It consists of the above fiber spinning members. Here, an electromagnetic energy source consisting of a pair of ultraviolet lamps 40 and 42 is attached to the end of the robot arm 18.

In operation, the cutting machine 20 controls the roving yarns 22-2.
6 is cut and cut, and the cut fibers are cast into a porous mold part 6. At the same time, the binder is sprayed from the spray nozzle 36 to at least partially coat the porous mold part 6 and the fibers directed on the passages thereof. The mold part 6 is rotated as indicated by the arrow 38 while the fibers are directed to the mold part 6, and the robot is operated to scan the entire inner surface of the porous mold part 6 in time with the rotation. As a result, the fibers can be uniformly attached to the predetermined thickness over the entire inner surface of the mold portion 6.

After the fibers are put into the mold part 6, the mold is closed by the mold operating mechanism 12, the mold part 10 is put on the mold part 6, the fibrous mat is pressed, and the desired preform is obtained. Adjust to three-dimensional shape. The mold is formed of a material that transmits ultraviolet radiation, such as a general purpose transparent acrylic material that does not contain a linear lattice or an ultraviolet blocking agent. While the mold is closed, auxiliary lamps (or microwave sources) such as lamps 40, 42 and 43 are operated to irradiate the pressed fibrous mat with ultraviolet radiation to cure the ultraviolet energy curing binder. The fibers are combined and the pressed mat solidifies into a solid three-dimensional preform.

At this point, a preform is used to form the structural composite. Thus, the mold is opened and the preform is removed from the mold by another robot (not shown) similar to robot 14 and placed on conveyor 60 of discharge station 5 for storage or other molding operations. Put on.

Assuming that the preform has the characteristics of a preform for mounting and that it has an assembly to attach to, either the robot or any other robot will hold the preform 44 in the desired position, Alternatively, the preform 44 on the workbench is placed in a desired position to attach the reinforcing member with the strong fastening stage 4. Here, the preform 44 is shown as being located at a desired location on the workbench. Operating another robot 54 with the preform in this position, applying a UV energy curing binder from the storage container 52 via a pump 50 through a distributor or spray nozzle 48 attached to the end of the robot arm 56 of the robot 54, The binder is applied to at least one selected surface of the preform and / or assembly. Then
As with other robots, the reinforced insert 46 is placed in the desired location and brought into intimate contact with the preform at a selected area having a binder over it. Next, the robot 5
4 is positioned to deliver intense ultraviolet radiation to a selected area of the binder at an ultraviolet wall 58, which is connected to an ultraviolet light source (not shown). Alternatively, microwave radiation can be used for this purpose.

Prior to use in making the structural composite, a final operation known as "strong fastening" is performed a number of times to attach the reinforcing member or mounting member (reinforced structural member) to the preform. After the last assembled part is strongly fastened, the preform 44 carrying the additional member is transferred to the conveyor 60 of the discharge stage 5 by another robot (not shown).

The binder is cured with microwave technology or electron beam using the other binder of choice.

Referring to FIG. 2, the structure and features of a typical preform are illustrated. Here, the preform 4
4 is a plurality of generally horizontal or slightly inclined panels 62 having a plurality of outwardly extending vertical walls 64, 66 with generally U-shaped profile portions 68, 70, 72, respectively. Other shapes can be formed, which is consistent with directing the fibers to a capture support surface defined by the inner surface of the upper and lower mold parts, including the insertion plug.

Referring to FIG. 3, the process for making the structural composite is shown in flow chart form. This process includes the concept of oriented fiber and irradiation energy of the present invention. As already described, the roving yarn is drawn from the supply stage 3, cut by the cutter 20, rotated as indicated by arrow 38, and directed through the plenum structure to the porous member containing the sucked air. The cut fibers toward the porous member are sprayed together with the binder exiting from the spray nozzle 36.
Rotation of the porous member and scanning by the cutter 20 and spray nozzles 36 provide a uniform coating or mat of binder coated fibers deposited to a predetermined thickness.

In the embodiment shown, the porous member is a lower mold part 6 having a complementary upper mold part 10, which lower mold part 6 moves so as to close the mold so that the mat of fibers is reduced. Replicate exactly the desired dimensions and shapes of the preform.
The binder is an electromagnetic energy curing binder, here an ultraviolet energy curing binder, here the mold parts 6 and 1
The pressed mat is illuminated and cured with a number of UV lamps, shown as being incorporated into a zero.
The mold portions 6 and 10 are formed of a UV transparent material, such as a grid or a clear acrylic material that does not contain UV blocking agents for general purposes.

Next, the mold parts 6 and 10 are separated, the mold is opened, and a cured three-dimensional preform is taken out. The preforms here are 44P and 44CP, of which the characteristics of the final member 44P moving to the RTM or SRIM molding processing section 90 via the discharge stage 5 are assumed, or the preforms 44CP for mounting are used. Assuming features, these are moved to a fastening stage 4 for attaching assemblies such as reinforcing ribs, cores, covers and the like.

In the strong fastening station 4, the mounting preform 44CP has an external rib 74 connected thereto.
(And / or internal ribs), stiffener corners 76, core 78 and cover 80, the connection being made to the binder source 8
2 to 7 is performed by applying an ultraviolet energy curing binder to the preform 44CP for mounting, the ribs 74, the corners 76, and the selected surface area of the cover 80. The cover 80 holds the core 78 in the mounting preform 44CP,
8 does not necessarily need to be temporarily fastened to the preform for mounting. The purpose of the core 78 is to conserve material in subsequent RTM / SRIM molding processes. In this process, the plastic material travels through the hollow porous walls of the preform into pockets or cavities, which results in overuse of the material, increased weight of the applied plastic, and extended cure times.

Preform 4 for mounting binder and assembly
After mounting on the 4CP, the selected area is coated with a binder and further exposed to ultraviolet radiation through a number of ultraviolet lamps 84, 86, 88 or with a robotically operated ultraviolet beam as described above.

Finally, the strong fastening forms a preform SP with a patterned structure, which is then transferred via the discharge stage 5 to the RTM / SRIM processing section 90.

Although the applicant has described the invention in particular embodiments, many modifications and improvements of the present invention will readily occur to those skilled in the art without departing from the spirit and scope of the invention.
However, it goes without saying that all the inventions defined in the claims belong to the invention.

[0043]

The advantages provided by the method and apparatus of the present invention include the use of irradiation energy techniques, particularly for the basic fiber orientation process, to produce structured preforms while simultaneously matting. This eliminates the need to treat the web of material in a conventional manner, such as by hard tacking or handling and holding a single layer mat.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an improved oriented fiber and irradiation energy treatment method and apparatus for performing a treatment method according to the present invention including strong fastening.

2 is a perspective view of a preform formed by the method and apparatus of FIG.

FIG. 3 is a flow chart of a process for making a structural composite using the oriented fiber and irradiation energy processing methods of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Molding stage 2 Application stage 3 Supply stage 4 Strong fastening stage 5 Discharge stage 6 First mold part (lower mold part) 7 Plenum (air filled chamber) 8 Surface 10 Second mold part (upper mold) 12) Mold opening / closing mechanism 14, 54 Robot 20 Cutting machine 22, 24, 26 Roving 28 Tube 28 'Exit port 32 Binder 34 Pump 36, 48 Spray nozzle 40, 42, 43 Lamp 44, 44P, 44CP Preformed product 46 Reinforcement Insertion Section 50 Pump 52 Storage Container 60 Conveyor 74 Rib 76 Reinforced Corner 78 Core 80 Cover 90 Molding Processing Section

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) D04H 1/00-18/00

Claims (10)

(57) [Claims] 1. A mold having a porous first mold part and a second mold part for pressing, wherein when both mold parts are closed, the desired three-dimensional shape of the preform is obtained and is arranged inclined to one another. In a method of making a preform having a solid three-dimensional structure using a separable mold having an inner surface forming an inner corner portion and an outer corner portion, the following steps are performed. Then, the electromagnetic energy curing binder is sprayed on the cut fibers,
At least partially cover the fiber with the binder without closing the gap between the fibers, cut and advance the fiber partially covered with the binder to the porous first mold part, and at the same time, pass through the first mold part The air flow is directed so that the fibers are directed toward the surface of the first mold part and adhere to the entire surface to a predetermined thickness, the second mold part is closed, and the binder is coated and cut. Press the closed fiber so that the fibers bridging the inner and outer corners of the closed mold deform into the desired shape determined by the corners of the closed mold. The desired three-dimensional shape of the preform between the second mold part and the porous first mold part, applying electromagnetic energy to the coated and pressed fibers in the closed mold. Hardens the binder and binds the fibers to form a solid three-dimensional preform Papermaking, the mold is opened, wherein the consisting of extracts preforms rigid three-dimensional structure from the mold. 2. The step of spraying the electromagnetic energy-curable binder further comprises spraying the binder simultaneously during the step of advancing the cut fibers to the porous mold portion, and coating the fibers while cutting and advancing the fibers. 2. A process according to claim 1, wherein
The method described in. 3. The method according to claim 1, wherein the step of spraying the electromagnetic energy-curing binder is a step of advancing the cut fibers to a mold portion and then spraying the binder on the cut fibers. . 4. The step of spraying a binder and the step of applying electromagnetic energy are respectively a step of spraying an ultraviolet energy curing binder onto the cut fibers and a step of applying ultraviolet radiation to the pressed fibers in a mold. The method of claim 1, wherein the method comprises: 5. The method of claim 5, further comprising: moving the rigid three-dimensional preform to a strong fastening position; applying an ultraviolet energy curable binder to at least one selected area of the preform; Moving the at least one selected binder-coated area into close contact with the preform; and radiating ultraviolet energy to the at least one selected binder-coated area to cure the binder and pre-assemble the assembly. 5. The method of claim 4, further comprising the step of attaching to a molded article. 6. An apparatus for making a rigid three-dimensional structure preform, wherein one mold portion has an inner surface that is complementary to an inner surface of the other mold portion, and both complementary inner surfaces. Replicates the desired three-dimensional structure of the preform, including any inner or outer corners of the preform, and passes through the mold portion because the inner surface of the first mold portion is porous. A separable mold consisting of first and second mold parts, wherein the mold part is a material that supports airflow and is transparent to predetermined electromagnetic radiation at least on the inner surface, Means for directing the air flow through one mold part, directing the fibers to the surface of the first mold part and adhering the entire surface to a predetermined thickness, cutting means for cutting the reinforcing material into short fibers And the cut fibers are discharged onto the first mold part and pass through the first mold part A reinforcing material supply unit for supplying a reinforcing material including discharge means to be retained therein by an air flow; a binder source for supplying a binder that cures in response to the predetermined electromagnetic radiation; Spraying means for spraying a binder onto the cut fibers at least partially without closing the gaps, and forming the corners of the mold that closes the fibers bridging the inner and outer corners into the desired shape Means for closing the separable mold parts so as to deform and press the cut and cut fibers into a preform of the desired three-dimensional structure between the two mold parts; Applying electromagnetic energy to the stiffened fibers, curing the binder in a closed mold, bonding the fibers to form a solid three-dimensional structure preform, opening the mold, rigid three-dimensional structure preform From the mold Apparatus for producing a preform of the rigid three-dimensional structure characterized by comprising means from issuing Ri. 7. The preform of claim 6, wherein the spraying means is arranged for spraying the fibers into the mold while cutting the fibers. Equipment to do. 8. Apparatus according to claim 6, wherein the spraying means is arranged for spraying the fibers after placing the fibers in the mold. . 9. The three-dimensional structure of claim 6, wherein the binder source provides a binder that cures in response to ultraviolet energy, and wherein the mold portion is formed of a material that transmits ultraviolet energy. Equipment for producing preforms with a structure. 10. A means for applying an ultraviolet energy curable binder to at least one selected area of the preform received from the mold, and moving the assembly to at least one selected area coated with the binder. And means for irradiating the selected binder-coated area with ultraviolet energy to cure the binder and attach the assembly to the preform. An apparatus for producing a preform having a solid three-dimensional structure according to claim 9.