JP7015268B2 - Method of attaching fiber bundles and method of manufacturing molded products - Google Patents

Description

The present invention relates to an apparatus and a technique for manufacturing a fiber reinforced plastic (FRP) molded product by attaching a fiber bundle impregnated with a resin to a surface to be attached.

A fiber bundle such as carbon fiber impregnated with a resin in advance to form a tape is often called a prepreg tape, a UD tape, or the like. Although not strictly, when the resin is semi-curable and thermosetting, it is often called prepreg tape, and when it is thermoplastic, it is often called UD tape, and this definition also applies to this specification. do.

These prepreg tapes and UD tapes are often used as intermediate materials for molding composite materials.

For example, prepreg tape and UD tape are wound around a core material (often called a mandrel) that rotates around one axis while applying tension, and when the desired outer shape is achieved, it is removed from the mandrel and molded. There is a manufacturing method to do. This is a kind of manufacturing method called tape winding and filament winding.

Further, there is a manufacturing method in which the prepreg tape and the UD tape are attached to the surface to be attached while being heated and pressurized to form a composite material having a desired shape. This manufacturing method has various names such as ATL (Auto Tape Layup), ATW (Auto Tape Welding), and AFP (Auto Fiber Placement), but is unified to ATL in the present specification. The fiber bundle pasting device based on ATL is referred to as an ATL device.

Further, there are cases where only one layer of the prepreg tape and UD tape is attached to the surface to be attached, and there are cases where the prepreg tape and the UD tape are laminated and attached over a plurality of layers on the surface to be attached. As a matter of course, in the case of laminating a plurality of layers, the prepreg tape and the UD tape, except for the bottom layer, are further affixed on top of these already affixed.

As an example of the former, there is a case where a prepreg tape or UD tape of a predetermined length is attached to a predetermined place for the purpose of partially reinforcing the molded product of a thermoplastic or thermosetting resin, improving the rigidity, and protecting the surface. ..

As an example of the latter, as in the manufacturing method such as tape winding, prepreg tape and UD tape are laminated on the mandrel and attached in multiple layers, and when the desired thickness and shape are obtained, they are removed to obtain the desired shape. There is a manufacturing method to obtain. When the desired shape is obtained by such a manufacturing method, in the case of prepreg tape, for complete curing, it is heated by a vacuum heating tank called an autoclave or the like to complete the thermosetting, and the molded product is completed. ..

In the case of UD tape, since it is a thermoplastic resin, it is not necessary to heat it in a subsequent step, and in many cases, molding as a composite material is completed only by a pasting step.

In the ATL device, when the prepreg tape or UD tape is attached to the affixed surface, the prepreg tape or UD tape is held at least temporarily, and the prepreg tape or UD tape is attached to the affixed surface along the affixed path. On the other hand, an ATL head is often used in which a prepreg tape or a UD tape is attached while being heated and pressurized while moving relatively.

Further, it is desired that the surface to be attached is a free curved surface, and therefore, the operation of the ATL head is often required to have a three-dimensional (translational, rotational) degree of freedom. Therefore, the ATL head is often attached to an articulated robot or to a so-called gantry structure that combines orthogonal and rotational movement systems.

Japanese Patent Publication No. 2014-511781

The ATL head as described above requires a prepreg tape, a UD tape, or a heating means for heating the surface to be attached. As described above, since the ATL head moves relative to the surface to be attached, non-contact heating is preferable when heating the surface to be attached. Therefore, this heating source has the feature of non-contact. Radiant light sources such as lasers and IR lamps are often used.

However, although the laser light source has the features of high output, high energy density, and easy output control, it is not expensive including the oscillation tube, optical fiber (light guide tube), optical system, power supply, and control device. In addition, there are many regular replacement parts such as an oscillation tube, and there is a problem that the initial cost and the running cost are high.

Also, in the case of a laser (not limited to a radiant light source whose wavelength is in the visible region), its absorption capacity differs depending on the surface condition such as the color and glossiness of the surface to be attached. There is also the problem that the heating efficiency changes.

Further, since the energy density of the IR lamp is lower than that of the laser light source, the heating efficiency is often low. This led to the problem that it was difficult to improve the sticking speed. Therefore, in order to obtain sufficient heating efficiency (pasting speed), there is no choice but to use a high-power IR lamp, which is not as expensive as a laser light source, but is still expensive.

On the other hand, as a substantially non-contact heating method, there is heating with a high-temperature gas (hot air heating). In this method, a high-temperature air flow is wiped from a nozzle or the like against the object to be heated to perform local heating. Although this hot air heating has a simple structure and is significantly cheaper than a laser light source or an IR lamp, it has a problem that the controllability of the heating temperature of the object to be heated is inferior to that of radiant heating such as a laser light source. This is because the gas is heated by a heating source such as electric heat, which is sprayed on the surface of the object to be heated, and the object to be heated is heated, which is a two-step energy transfer.

In view of the above problems, in the method for attaching a fiber bundle according to the first aspect of the present invention, a fiber bundle impregnated with a thermoplastic resin in at least a part thereof is heated and pressed to form the same thermoplastic resin as the fiber bundle. It is a method of attaching a fiber bundle to be attached to a surface to be attached to an injection-molded product, and the heating is performed by a plurality of types of heating means, one of which is a radiant heating means and the other of which is a hot air heating means.

In the fiber bundle sticking method according to the first aspect, the heating load ratio by the hot air heating means is preferably larger than that of the radiant heating means.

In the fiber bundle sticking method according to the first aspect, preferably, the surface temperature of the sticking surface and / or the fiber bundle is measured, and the output of the radiant heating means is controlled based on the measurement result.

In the fiber bundle sticking method according to the first aspect, the hot air ejected from the hot air heating means preferably contains an inert gas.

In the fiber bundle attaching method according to the first aspect, the fiber bundle preferably contains carbon fibers.

In the fiber bundle attaching method according to the first aspect, the resin preferably contains a thermoplastic resin.
The method for producing a molded product according to the second aspect of the present invention includes a step of attaching a fiber bundle to a surface to be attached by the fiber bundle attaching method according to claim 1.

In the inventions according to claims 1 and 2, by using the radiant heating means and the hot air heating means in combination, the output of the radiant heating means can be reduced, and the initial cost and the running cost can be reduced. can get.

According to the third aspect of the present invention, by controlling the output of the radiant heating means having excellent controllability based on the measurement result of the surface temperature measuring means, an ATL device having excellent heating controllability of the object to be heated can be realized. ..

According to the invention of claim 4, since the hot air contains an inert gas, the surface to be heated and the fiber bundle, which are mostly combustibles, can reduce the risk of ignition.

In the inventions of claims 5 and 6, an ATL device applicable to carbon fiber and thermoplastic UD tape can be realized.

It is a figure which shows one Embodiment of the ATL apparatus by this invention. It is a figure which shows the structure of the ATL head. It is a figure explaining the sticking operation of the ATL apparatus by this invention. It is a figure explaining the transfer of the fiber bundle from the fiber bundle supply means to the ATL head. It is a figure which shows the relative positional relationship of ATL head and work. It is a figure which shows the relative positional relationship of ATL head and work.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and below.

FIG. 1 is a diagram showing the entire ATL device 1 according to the present invention. The ATL device 1 accommodates an articulated robot 2, an ATL head 3 provided at the tip of an arm 2a of the articulated robot, a fiber bundle supply means 4 for supplying a fiber bundle A previously cut to the ATL head 3, and a fiber bundle A. It is composed of a supply table 13 which is a fiber bundle accommodating means, a work 5 having a surface to be attached 5a, a work table 6 on which the work 5 is mounted, and the like.

In the present embodiment, the work 5 is an injection-molded product of a thermoplastic resin, and a pre-cut UD tape A made of a carbon fiber bundle impregnated with the same thermoplastic resin is attached to the surface of the work 5 to reinforce the work 5. Is the purpose of pasting. As a matter of course, the shape of the work 5, the position where the UD tape A is attached, and the length to which the UD tape A is attached are predetermined in design.

As the articulated robot 2, a commercially available general-purpose industrial robot can be used. The ATL head 3 is attached to the tip of the arm 2a of the articulated robot 2.

The ATL head 3 covers the fiber bundle while sandwiching and pressing the infrared lamp 8 as the radiant heating means, the hot air nozzle 18, the feeder 9, and the fiber bundle as the hot air heating means on the base material 7. It has a pressing means 10 to be attached to the attachment surface 5a, a non-contact temperature sensor 17, and the like. (See also FIG. 2) The hot air nozzle 18 has a built-in heater itself, and heats nitrogen gas supplied from a supply system (not shown) and ejects it from the tip of the nozzle. It is also possible to use carbon dioxide gas instead of nitrogen gas.

The infrared lamp 8 has an optical system such as a reflector or a lens (not shown), and aims at a slightly upstream side of the attachment point shown by B in FIG. 2 and concentrates infrared rays in the region indicated by the double arrow C in the figure. The attached surface 5a existing in the region is mainly heated.

The hot air nozzle 18 ejects heated nitrogen gas at a predetermined temperature and a predetermined flow rate from its tip. As shown in FIG. 5, heated nitrogen gas is ejected slightly upstream from the sticking point B, approximately in the region indicated by the arrow E in the figure, and the hot air nozzle 18 also mainly heats the sticking surface 5a.

The feeder 9 for holding and transporting the UD tape A has a set of transport belt pairs 11, and the UD tape A is sandwiched and transported between the transport belts 11a and 11b. Heaters 12a and 12b also exist in the conveyor belts 11a and 11b, and the conveyor belts 11a and 11b can be preheated to a predetermined temperature. By transporting the UD tape A between the preheated transport belts 11a and 11b, it is possible to preheat the UD tape A to a predetermined temperature before the UD tape A reaches the attachment point B. This preheating is not essential and may not be necessary depending on the material, thickness, etc. of the UD tape A and the work 5.

The pressing means 10 includes a pressing roller 10a that affixes the UD tape A to the affixed surface 5a while sandwiching and pressing the UD tape A with the affixed surface 5a, and an air cylinder 10b that is a pressing source of the pressing roller 10a.

The fiber bundle supply means 4 is a supply stand 13 (corresponding to a fiber bundle accommodating means) on which UD tape A cut to a predetermined length is loaded, and a pickup hand 14 that picks up one UD tape A from the supply stand 13. , Consists of gantry shafts 15 and 16 for moving the pickup hand 14 vertically and horizontally.

The pickup hand 14 has a plurality of vacuum suction chucks 14a, and picks up only one UD tape A loaded on the supply table 13 by the vacuum suction chucks 14a.

Next, the operation of attaching the UD tape A by the ATL device 1 will be described in order with reference to FIG. The part number notation is omitted for the members that are not directly related to the explanation of the pasting operation.

First, as shown in FIG. 3, the pickup hand 14 picks up only one UD tape A on the supply base 13 by the operation of the gantry shafts 15 and 16. At this time, as can be seen in FIG. 3, the vacuum chuck 14a sucks and picks up the UD tape A in a state where both ends (at least one end) of the UD tape A protrude from both ends of the pickup hand 14 in the extending direction.

Next, the pickup hand 14 moves to the delivery position. The UD tape A held by the pickup hand 14 at the delivery position is delivered to the feeder 9 in the ATL head 3. The delivery position is not particularly limited as long as it is within the common area of the movable area of the pickup hand 14 by the gantry axes 15 and 16 and the movable area of the ATL head 3 by the articulated robot 2.

At the delivery position, as shown schematically in FIG. 4, the articulated robot 2 is inserted so that one end of the UD tape A held by the pickup hand 14 is slightly inserted into the insertion port 20 of the feeder 9 in the ATL head 3. Works. When one end of the UD tape A is inserted into the feeder 9 to a predetermined length, the suction of the vacuum chuck 14a is added or removed, and the UD tape A is delivered to the ATL head 3. At the same time, the feeder 9 operates to convey the UD tape A to a predetermined standby position.

The articulated robot 2 is operated again to move the ATL head 3 to the attachment start position. Subsequently, the articulated robot 2 is operated to press the pressing roller 10a against the surface to be attached 5a. At this time, the feeder 9 operates at the timing when the pressing roller 10a comes into contact with the affixed surface 5a, and the UD tape A is conveyed so that the tip of the UD tape A is just sandwiched between the pressing roller 10a and the affixed surface 5a. .. At this time, the infrared lamp 8 and the hot air nozzle 18 also start lighting and operation in synchronization with this timing, and start heating the surface to be attached 5a.

The ATL head 3 moves and swings on the sticking surface 5a of the work 5 along the sticking path of the UD tape A, and sticks the UD tape A to the sticking surface 5a. During that time, the feeder 9 is operating (the state shown in FIG. 1), and the UD tape A is conveyed and supplied toward the attachment point B.

When the UD tape A has been attached to the rear end, the infrared lamp 8 is turned off, the operation of the hot air nozzle 18 is stopped, and the pressing of the pressing roller 10a and the attached surface 5a is released by the operation of the articulated robot 1, and one piece is released. The application of UD tape A is completed.

Hereinafter, the same operation is repeated, and the UD tape A is attached onto the surface to be attached 5a.

By the way, the ATL head 3 makes a so-called swinging motion so that the pressing roller 10a always presses the attached surface 5a via the UD tape A from the direction (normal direction) orthogonal to the attachment surface 5a (FIG. 6). reference). Therefore, as shown in FIG. 6, the relative positional relationship between the work 5 and the ATL head 3 changes depending on the unevenness (inclination direction) of the sticking surface 5a of the work 5. Therefore, the distance from the infrared lamp 8 or the hot air nozzle 18 to the sticking surface 5a also changes slightly. Therefore, although it is slight, the heating efficiency due to the infrared rays from the infrared lamp 8 and the hot air from the nozzle 18, specifically, the heating reaching temperature of the surface to be attached 5a changes.

The heating reached temperature is measured by the non-contact temperature sensor 17, and the output of the temperature sensor 17 is fed back to the output control device of the infrared lamp 8 and the control device of the hot air nozzle 18 (neither of them is shown) to them. In principle, it is possible to adjust the output of and compensate for the change in the temperature reached by heating.

However, as described above, the hot air nozzle 18 has a problem that the controllability of the heating temperature of the object to be heated is inferior. Therefore, even if an attempt is made to feed back the temperature measurement result to the hot air nozzle 18 to compensate for the change in the temperature reached by heating, sufficient responsiveness is often not obtained.

Therefore, the temperature measurement result of the temperature sensor 17 is compensated for the change in the temperature reached by heating only by the infrared lamp 8 having excellent responsiveness, or by preferentially ford backing to control the output of the infrared lamp 8.

Further, in this embodiment, the hot air nozzle 18 as a hot air heating means and the infrared lamp 8 as a radiant heating means are used in combination as a heating source to mainly heat the surface of the surface to be attached 5a. The burden ratio of the hot air nozzle 18 should be larger than that of the infrared lamp 8.

To briefly explain this, when it is necessary to heat the surface to be attached 5a from room temperature to 200 ° C., for example, a hot air heating means such as a hot air nozzle 18 is used for 150 ° C., and an infrared lamp 8 or the like is used for the remaining 50 ° C. It means setting each output so that the radiant heating means bears. By increasing the burden ratio of the relatively inexpensive hot air heating means and reducing the burden ratio of the expensive radiant heating means, it is possible to use a relatively inexpensive low output radiant heating means, resulting in an apparatus. The overall cost increase can be suppressed.

By setting the burden ratio in this way, the effect of suppressing the cost increase of the entire device is particularly effective when the surface to be attached has a surface having a low absorption of radiant energy such as white or high gloss.

In addition, this burden ratio is, for example, the reached temperature when the sticking operation is performed under the same conditions (speed, work, UD tape, etc.) and only the radiant heating means is operated, and when only the hot air heating means is operated. It can be determined by measuring and comparing the ultimate temperature. In this embodiment, the gantry structure is used for the fiber bundle supply means 4, but an articulated robot may be used instead.

By the way, in the present invention, a cutting step of cutting the fiber bundle to a predetermined length is required in advance, and various known cutting devices can be used for this. Further, since the cutting mechanism is not required in the ATL head 3, the ATL head 3 is suitable because it leads to weight reduction and simplification.

A step of supplying the cut fiber bundle A to the fiber bundle accommodating means (supply table 13) is also required, but this may be performed manually, or various known automatic transfer devices and mechanisms may be used. ..

Normally, in an assembly device using such a robot or the like, it is customary to surround the movable range of the robot with a safety fence or the like in order to ensure the safety of workers. At this time, regarding the present invention, for example, the fiber bundle accommodating means (supply table 13) is arranged outside the safety fence, etc., and the safety fence or the like is provided with an automatically opening / closing door member or the like, and is provided inside the safety fence or the like. The fiber bundle supply means may pick up the fiber bundle A via the door member. This is preferable because it is not necessary to stop the sticking operation of the ATL device 1 when the fiber bundle A is manually supplied to the supply table.

1 ATL device 2 Articulated robot 3 ATL head 4 Fiber bundle supply means 5 Work 6 Work base 7 Base material 8 Infrared lamp 9 Feeder
10 Pressing member
10a Pressing roller
11 Conveyor belt pair
11a, 11b Conveyor belt
12a, 12b heater
13 Supply stand
14 pickup hand
15, 16 gantry axis
17 Temperature sensor
18 Hot air nozzle

Claims (6)

A fiber bundle sticking method in which a fiber bundle impregnated with a thermoplastic resin at least partially in advance is attached to the surface to be adhered to an injection-molded product of the same thermoplastic resin as the fiber bundle while heating and pressurizing . A method for attaching a fiber bundle, wherein at least one of the heating is a radiant heating means and at least one of the other is a plurality of types of heating means which are hot air heating means. The fiber bundle sticking method according to claim 1, wherein the heating load ratio by the hot air heating means is larger than that of the radiant heating means. The method for attaching a fiber bundle according to claim 1 or 2, wherein the surface temperature of the surface to be attached and / or the surface temperature of the fiber bundle is measured, and the output of the radiant heating means is controlled based on the measurement result. The method for attaching a fiber bundle according to any one of claims 1 to 3, wherein the hot air ejected from the hot air heating means contains an inert gas. The method for attaching a fiber bundle according to any one of claims 1 to 4, wherein the fiber bundle contains carbon fiber. A method for manufacturing a molded product, which comprises a step of attaching a fiber bundle to a surface to be attached by the fiber bundle attaching method according to claim 1.

Images