KR20180031377A - Compression molding method for carbon fiber reinforced thermoplastics - Google Patents

Abstract

The present invention relates to a compression molding method for a thermoplastic composite material reinforced with carbon fiber. In a compression molding apparatus for a thermoplastic composite material reinforced with carbon fiber, a plurality of pressure cylinders is configured to be tuned to control each other, and tuning control driving of pressure cylinders is divided into an initial drive mode and a pressurization mode so that an initial follow-up error due to the tuning control is not transmitted to the bolster, thereby achieving a compact structure while preventing damage to a mold and obtaining a product with higher precision.

Description

TECHNICAL FIELD [0001] The present invention relates to a compression molding method for a carbon fiber-reinforced thermoplastic composite material,

The present invention relates to a compression molding method of a compression molding apparatus for a carbon fiber-reinforced thermoplastic composite material.

The use of synthetic resins has been widely used throughout the industry, and the use of synthetic resin molded articles has been rapidly increasing in applications where metals and the like have been used.

The problems to be solved by such synthetic resin molded articles can be summarized as weight saving and improvement of physical properties. Although there is a difference depending on the application field, a material that is gradually lighter but stronger in strength is required, and particularly in the fields of automobiles, electronics, precision machinery parts, and the like.

Among various synthetic resins, thermoplastic resins have excellent chemical resistance and moldability, but their heat resistance and mechanical strength are relatively weak. Due to the properties of the thermoplastic resin, it can not be applied to a field requiring high strength and has been reinforced with various organic and inorganic materials.

In particular, various attempts have been made to reinforce strength with reinforcing fibers. In reinforcing the strength by using the reinforcing fiber, it is very important to control the content of the reinforcing fiber and to contain the reinforcing fiber in the form of a long fiber without breakage in the final molded product.

CFRP (Carbon Fiber Reinforced Plastics) composites, which have recently been attracting attention as a lightweight material, can be used in various fields and have excellent mechanical properties. Therefore, in advanced countries such as Germany, Japan and USA, Various researches are being conducted on composite materials manufacturing systems and applied products.

Research on the development of parts using CFRP composite material is progressing actively in the automobile field in recent years, and this trend is accelerating as the emission regulation of automobile exhaust gas is strengthened around the world, and improvement of fuel efficiency by lightening is urgently required.

Non-ferrous metal materials such as aluminum and magnesium are used for lighter weight of automobiles, and polymer composite materials are used for non-ferrous metals. CFRP composites are used for these applications because of limited finite resources and difficulties in processing. And there is a need for intensive support to the auto parts industry.

The development of automobile parts using CFRP composite material is very important for productivity as well as light weight. In order to improve productivity, automation of manufacturing process and reduction of production time should precede.

As the matrix of CFRP composite material, thermosetting resin and thermoplastic resin are used. In the case of thermosetting resin, there are problems such as increase in molding cycle time due to curing reaction, impact resistance, and inability to recycle. .

In particular, the thermoplastic resin has the advantage of shortening the molding cycle time due to the fact that the curing reaction is unnecessary, and the productivity is high. However, the thermoplastic resin is put to practical use due to lack of original heat resistance and poor impregnation due to high viscosity at molding.

Currently, commercialized short fiber reinforced composite materials have not been able to increase the strength and stiffness characteristics as a general technique having a fiber length of about 0.2 to 0.5 mm in the manufacturing process. As a result, the length of the fiber is increased and the content of the fiber is increased, Development of thermoplastic composites using continuous fibers is needed.

The production process for manufacturing automobile parts using CFRP composite material is based on the manual production process by the early manual process, the injection process is used, and recently, the method of continuous production by directly inputting the fibers and the press molding Processes are being developed.

The LFT system using long fiber and thermoplastic resin is composed of LFT-G system for extrusion and press forming after manufacturing pellets impregnated with resin and fiber, LFT-D for compounding while impregnating with resin while cutting fiber to desired length System, LFT-G method is applied to the production of interior products mainly in large corporations in Korea, but there is no case where product production using LFT-D system is applied in domestic.

The LFT-D system, which is suitable for the production of structural parts with low production-molding cycle, can be produced by extruding composite materials directly by impregnating long fiber and thermoplastic resin, System, which can dramatically reduce the production time and increase the strength.

The production system using such a CFRP composite material can be largely composed of an extruder, a transfer device, and a press device.

The double press apparatus plays a role of compressing a CFRP composite material, and a pressing apparatus and a production process thereof which can compression-mold a CFRP composite material with high productivity and high precision are required.

Korean Patent No. 10-1419812 entitled " Compression Molding Apparatus and Compression Molding Method of Resin Molded Parts Containing Fiber "(registered on April 7, 2014) Korean Patent No. 10-1188374 entitled "Molding system and molding method of fiber-reinforced composite material" (2012. 9.27. Registration)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a compression molding apparatus for a carbon fiber-reinforced thermoplastic composite material, in which a plurality of pressure cylinders are tuned to each other, The drive is divided into the initial drive mode and the pressurizing mode so that the initial follow-up error due to the tuning control is not transmitted to the bolster, so that a compact configuration is possible, while the carbon fiber To provide a compression molding method of a reinforced thermoplastic composite material.

According to an aspect of the present invention, there is provided a cavity for a cavity, comprising: a lower mold cavity having an upper portion opened and a lower cavity formed at a lower portion thereof and having a vertical inner wall extending vertically downward from the opened upper portion to the cavity for cavity; ; A bolster in which the lower mold is provided at an upper portion; A bed on which the bolster is disposed; A plurality of tie rods extending perpendicularly to the bed; A slide disposed on an upper portion of the bolster, the slide including a plurality of vertically installed tie rods penetrating therethrough and guided by the plurality of tie rods; Tie rod clamping means provided on the slide for clamping the tie rod; And a vertical extending wall extending vertically upward from an edge of the upper surface of the cavity is formed, and a lower surface of the upper mold cavity An upper mold having an insertable upper mold projection; A plurality of transfer cylinders connected to the bed at the lower end and connected to the slider at an upper end to move the slides up and down; A plurality of pressing cylinders provided on the bed to move the bolster up and down and to provide a pressing force for compression molding to the bolster; Wherein the plurality of pressure cylinders are tuned to each other, wherein the cavity for the cavity of the lower mold is made of a carbon fiber-reinforced thermoplastic composite material in a state where the lower mold and the upper mold are separated from each other, A step of injecting a thermoplastic composite material; A lowering step of lowering the slide by lowering the slide in conjunction with a lowering of the slide by driving the transfer cylinder after the composite material loading step; A tie rod clamping step in which the tie rod clamping means clamps the tie rod after the top-type descending step; The bolster rises by the tuning control drive of the plurality of pressure cylinders after the tie-rod clamping step, and the lower mold is raised in conjunction with the elevation of the bolster so that the carbon fiber-reinforced thermoplastic composite material, Wherein the driving of the plurality of pressing cylinders to be driven by the tuning control is performed in an initial driving mode until the balls are in contact with the bolster in a state of being separated from the bolster, And a pressing mode for pressing the bolster while pressing the bolster after the initial driving mode. And a control unit.

As described above, according to the present invention, in a compression molding apparatus for a carbon fiber-reinforced thermoplastic composite material, a plurality of pressure cylinders are tuned to each other, wherein the plurality of pressure cylinders are tuned to be controlled in a driving mode and a pressure mode To provide a compression molding method of a carbon fiber-reinforced thermoplastic composite material capable of achieving a compact structure while preventing damage to a mold and obtaining a product with higher precision by preventing the initial follow-up error caused by the tuning control from being transmitted to the bolster do.

1 is a front view of a compression molding apparatus for a carbon fiber-reinforced thermoplastic composite material according to an embodiment of the present invention,
Fig. 2 is a side view of Fig. 1,
FIG. 3 is a detailed view of the tie rod portion in FIG. 1,
Fig. 4 is a detailed view of the mold of Fig. 1,
Fig. 5 is a view corresponding to Fig. 2 immediately after the phase-
Fig. 6 is an enlarged view showing the relationship between the pressurizing cylinder and the bolster in Fig. 5,
Fig. 7 is an enlarged view showing the relationship between the pressurizing cylinder and the bolster at the time when the pressurizing cylinder is in contact with the bolster,
Figure 8 corresponds to Figure 2 immediately after the compression molding step,
9 is an enlarged view showing the relationship between the pressurizing cylinder and the bolster in Fig.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention in the drawings, portions not related to the description are omitted, and like reference numerals are given to similar portions throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

The term " cylinder " refers to a device that mechanically performs a reciprocating linear motion of a piston or plunger by hydraulic pressure or pneumatic pressure. In the present specification, the cylinder is made up of a piston or a plunger. Generally, a hydraulic cylinder is used in a press apparatus.

FIG. 1 is a front view of a compression molding apparatus for a carbon fiber-reinforced thermoplastic composite material according to an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, FIG. 3 is a detailed view of a tie rod portion in FIG. 4 is a detailed view of the mold of Fig. 1, Fig. 5 is a view corresponding to Fig. 2 immediately after the upper mold lowering step, Fig. 6 is an enlarged view showing the relationship between the pressurizing cylinder and bolster of Fig. Fig. 8 is an enlarged view showing the relationship between the pressurizing cylinder and the bolster at the time when the pressurizing cylinder is in contact with the bolster, Fig. 8 is a view corresponding to Fig. 2 immediately after the compression molding step, This is an enlarged view showing the relationship between the cylinder and the bolster.

First, a compression molding apparatus for a carbon fiber-reinforced thermoplastic composite material used in the present invention will be described.

The compression molding apparatus includes a press 200, a mold 200 including a lower mold 210 and a top mold 220.

1 to 3, the press apparatus 100 includes a bolster 120 and a bed 110 sequentially disposed below a mold 200, a slide 110 disposed sequentially on the upper side of the mold 200, (130), and a crown (140).

The bolster 120 is provided with a lower mold 210 on an upper portion thereof and the bolster 120 is provided on an upper portion of the bed 110.

In the bed 110, a plurality of tie rods 150 (four tie rods 150 in this embodiment) are vertically arranged.

Each tie rod 150 has an intermediate portion passing through the slide 130 and an upper end fixed to the crown 140.

A tie rod 150 is disposed on the slide 130 so that the slide 130 is guided by the tie rod 150 in the upward and downward directions.

The slide 130 is provided with a tie rod clamping means 160 coupled to the male thread 151 of the tie rod 150 for clamping the tie rod 150. The slide 130 can be fixed to a predetermined position of the tie rod 150 by the tie rod clamping means 160 despite the driving of the pressing cylinder 180. [

The tie rod clamping means 160 includes a half nut screwed to the male thread 151 of the tie rod 150 and a half nut driving cylinder for driving the half nut.

Since the tie rod clamping means 160 is a known one, a detailed description thereof will be omitted.

The bed 110 is provided with a plurality of conveying cylinders 170 and a plurality of pressing cylinders 180.

The lower end of the transfer cylinder 170 is connected to the bed 110 and the upper end of the transfer cylinder 170 is connected to the slide 130 to move the slide 130 up and down.

That is, the transfer cylinder 170 is a driving source for moving the slide 130 up and down.

The pressurizing cylinder 180 is provided on the bed 110 to move the bolster 120 up and down and provide a pressing force to the bolster 120.

That is, the pressurizing cylinder 180 is a driving source that not only moves the bolster 120 up and down, but also provides a pressing force for compression molding.

In this embodiment, the pressurizing cylinder 180 and the bolster 120 are not assembled with each other, and the pressurizing cylinder 180 can only push the bolster 120 upward.

A bolster clamp 190 is provided on the pressurizing cylinder 180 (see Fig. 6).

A leaf spring 191 is provided between the bolster clamp 190 and the pressing cylinder 180 to elastically support the bolster clamp 190 downward to clamp the bolster 120. In addition, So that the bolster clamp 190 can release the clamping of the bolster 120. As shown in FIG.

In this embodiment, the bolster 120 is configured to be movable, and the bolster clamp 190 can release the clamping to the bolster 120 when the bolster 120 is to be moved. In the compression molding operation, (120).

Next, the mold 200 will be described with reference to Figs. 1 and 4. Fig.

The mold 200 includes a lower mold 210 and a top mold 220.

A lower mold groove 211 having an opened upper surface is formed at the upper portion of the lower mold 210.

A cavity groove 211a is formed in a lower portion of the lower mold cavity 211 and a vertical inner side wall 211b extending vertically downward from the opened upper portion to the cavity groove 211a is formed . In other words, the lower mold cavity 211 has a vertically concave groove shape.

The cavity groove 211a is a portion where a carbon fiber-reinforced thermoplastic composite material 10 to be described later is charged and compression molded.

The lower mold 210 is fixed to the upper portion of the bolster 120.

In addition, the upper die 220 is fixed to a lower portion of the slide 130.

The upper mold 220 has an upper mold protrusion 221 insertable into the lower mold cavity 211.

The upper mold projection 221 has a cavity upper surface 221a formed on the lower surface thereof for forming a cavity together with the cavity groove 211a and a vertically extending wall 221b extending vertically upward from the edge of the cavity upper surface 221a. (Not shown).

The upper mold protrusion 221 of the upper mold 220 and the lower mold 210 are inserted into the lower mold cavity 211 of the lower mold 210 to be inserted into the cavity 211a of the lower mold 210, Is closed by the cavity top surface 221a of the upper mold 220 to form a cavity

At this time, the vertical inner wall 211b of the lower mold 210 and the vertically extending wall 221b of the upper mold 220 are arranged in parallel with each other extending in the vertical direction.

When the upper mold protrusion 221 of the upper mold 220 is inserted into the lower mold recess 211 of the lower mold 210, the vertical inner wall 211b of the lower mold 210 and the vertically extending wall 221b of the upper mold 220 ) Are arranged parallel to each other over a considerable length. In the case of this embodiment, it reaches about 60 mm.

The reason why the vertical inner wall 211b of the lower mold 210 and the vertically extending wall 221b of the upper mold 220 have a long length is that the carbon fiber-reinforced thermoplastic composite material 10 leaks to the outside during compression molding It is surely to stop.

On the other hand, in this embodiment, the plurality of pressure-applying cylinders 180 are tuned to each other. In this embodiment, two pressure cylinders 180 are provided, one of which is a master pressurizing cylinder and the other is a slave pressurizing cylinder that follows the position of the master pressurizing cylinder , This system adopts master slave tuning control.

The use of the positional tuning control system using the multiple hydraulic cylinders as described above can prevent eccentricity and improve the product accuracy, and the whole facility can be made more compact by employing a plurality of hydraulic cylinders.

The operation of the above-described compression molding apparatus will be described.

(1) Step of applying composite material

The carbon fiber-reinforced thermoplastic composite material 10 is first placed in the cavity groove 211a of the lower mold 210 in a state where the lower mold 210 and the upper mold 220 are separated from each other (that is, the mold 200 is opened) .

At this time, the carbon fiber-reinforced thermoplastic composite material 10 is formed by extruding pellets and carbon fibers for resin composition into an extruder and kneading the carbon fiber with the resin composition, and cutting the extruded resin into a predetermined length. And is transferred to the press apparatus 100 and put into the cavity 211a of the lower mold 210. [

(2) Upside down step

The slide 130 is lowered by driving the conveying cylinder 170 after the composite material injecting step and the upper die 220 is lowered in conjunction with the lowering of the slide 130 (see FIGS. 5 and 6).

In this state, the carbon fiber-reinforced thermoplastic composite material 10 is not yet compressed.

The slide cylinder 130 and the upper mold 220 are lowered at a higher speed to increase the compression molding speed.

(3) Tie rod clamping step

The tie rod clamping means 160 clamps the tie rod 150 after the top-down step.

Thus, the slide 130 is firmly fixed to the tie rod 150, and the slide 130 and the upper mold 220 can maintain their positions even during the compression molding process of the pressing cylinder 180 described later.

(4) compression molding step

After the tie rod clamping step, the bolster 120 is lifted by the tuning control of the plurality of pressurizing cylinders 180, and the lower mold 210 is lifted in conjunction with the bolster 120 lifting up to the cavity groove 211a The inserted carbon fiber-reinforced thermoplastic composite material 10 is compression molded between the upper mold protrusion 221 of the upper mold 220 and the lower mold cavity 211 of the lower mold 210. 8 is a state immediately after the compression molding is completed.

At this time, driving of the plurality of pressure-applying cylinders 180 to be tuned-controlled is divided into an initial driving mode and a pressing mode.

The initial driving mode refers to driving until the pressing cylinder 180 is in contact with the bolster 120 in a state where the pressing cylinder 180 is spaced apart from the bolster 120. In the initial drive mode, since the pressurizing cylinder 180 and the bolster 120 are spaced apart from each other, the pressurizing cylinder 180 is raised while the bolster 120 is kept stationary.

That is, the initial driving mode of the pressurizing cylinder 180 refers to driving up to the contact with the bolster 120 as shown in FIG. 7 in a state where the initial driving mode is separated from the bolster 120 as shown in FIG.

This is because the plurality of pressure-applying cylinders 180 to be controlled in tuning are designed so that a relatively large follow-up error occurs at the beginning of the drive and that the follow-up error does not affect the rise of the bolster 120 to the lower die 210. If a plurality of pressing cylinders 180 raise the bolster 120 to the lower mold 210 at the beginning of the driving of the plurality of pressing cylinders 180, the following error generated in the plurality of pressing cylinders 180 is transmitted to the lower mold The vertical inner wall 211b of the lower mold 210 causes extreme wear and contact with the vertical extending wall 221b of the upper mold 220 so that the mold 200 is damaged In addition, there is a risk of product failure.

After the initial drive mode, the pressurizing cylinder 180 operates in a pressurizing mode in which the bolster 120 is pressed while being pressed.

That is, the pressurizing mode of the pressurizing cylinder 180 refers to driving up to a state in which the bolster 120 is lifted as shown in Figs. 8 and 9 while in contact with the bolster 120 as shown in Fig.

The carbon fiber-reinforced thermoplastic composite material 10 is compression molded between the upper mold 220 and the lower mold 210 by the pressing mode.

(5) Takeout step

The slide 130 and the upper mold 220 are moved upward by the driving cylinder 170 after the compression molding step and the bolster 120 and the lower mold 210 are moved downward by the driving of the pressing cylinder 180, The mold 200 is opened, and then the carbon fiber-reinforced thermoplastic composite material 10 after compression molding is taken out.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the embodiments described above are intended to be illustrative, but not limiting, in all respects. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

10: Carbon Fiber Reinforced Thermoplastic Composite
100: Press apparatus
110: Bed
120: Bolster
130: Slide
140: Crown
150: tie rod 151: male thread portion
160: tie rod clamping means
170: Feeding cylinder
180: Pressure cylinder
190: Bolster clamp 191: leaf spring
200: Mold
210: lower mold 211: lower mold groove
211a: Cavity groove 211b: Vertical inner side wall
220: upper mold 221: upper mold projection
221a: upper surface for cavity 221b: vertically extending wall

Claims (1)

A lower mold having a lower mold cavity in which an upper portion is opened and a cavity for a cavity is formed in the lower portion and a vertical inner side wall extending downward from the upper portion vertically to the cavity for cavity is formed;
A bolster in which the lower mold is provided at an upper portion;
A bed on which the bolster is disposed;
A plurality of tie rods extending perpendicularly to the bed;
A slide disposed on an upper portion of the bolster, the slide including a plurality of vertically installed tie rods penetrating therethrough and guided by the plurality of tie rods;
Tie rod clamping means provided on the slide for clamping the tie rod;
And a vertical extending wall extending vertically upward from an edge of the upper surface of the cavity is formed, and a lower surface of the upper mold cavity An upper mold having an insertable upper mold projection;
A plurality of transfer cylinders connected to the bed at the lower end and connected to the slider at an upper end to move the slides up and down;
A plurality of pressing cylinders provided on the bed to move the bolster up and down and to provide a pressing force for compression molding to the bolster;
A compression molding apparatus for a carbon fiber-reinforced thermoplastic composite material comprising:
Wherein the plurality of pressure cylinders are tuned to each other:
A step of injecting a carbon fiber-reinforced thermoplastic composite material into a cavity for a cavity of the lower mold with the lower mold and the upper mold separated from each other;
A lowering step of lowering the slide by lowering the slide in conjunction with a lowering of the slide by driving the transferring cylinder after the loading of the composite material;
A tie rod clamping step in which the tie rod clamping means clamps the tie rod after the top-type descending step;
The bolster rises by the tuning control drive of the plurality of pressure cylinders after the tie-rod clamping step, and the lower mold is raised in conjunction with the rising of the bolster, so that the carbon fiber-reinforced thermoplastic composite material injected into the cavity- Wherein the driving of the plurality of pressing cylinders to be driven by the tuning control is performed in an initial driving mode until the balls are in contact with the bolster in a state of being separated from the bolster, And a pressing mode for pressing the bolster while pressing the bolster after the initial driving mode.
Wherein the carbon fiber-reinforced thermoplastic composite material is a carbon fiber-reinforced thermoplastic composite material.

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