Prepreg compression molding (PCM) apparatus and method

Abstract

A prepreg compression molding (PCM) apparatus and method are disclosed. The prepreg compression molding (PCM) method includes the steps of: adjusting a temperature of a mold; moving a hydraulic-side mold connected to a hydraulic cylinder to a preset position; applying a preset pneumatic pressure to a pneumatic cylinder so as to move a pneumatic-side mold; returning the pneumatic-side mold to an initial position; and returning the hydraulic-side mold to an initial position. According to the present invention, by finely adjusting a pressure, a molded product having excellent characteristics can be manufactured, and defects such as bubbles generating during a manufacturing process can be reduced.

Description

Prepreg compression molding (PCM) apparatus and method

[0001] The present invention relates to a prepreg compression molding (PCM) apparatus and method, and in particular, by using a hydraulic cylinder and a pneumatic cylinder to precisely apply multiple pressures, operating the hydraulic cylinder at multiple speeds, and adding a process to prevent bubble defects, it is possible to manufacture prepreg compression molded products with high productivity and excellent quality.

[0002] Prepreg is an intermediate substrate for fiber-reinforced composites, consisting of a molding material in which reinforcing fibers are pre-impregnated with a matrix resin. A molded product is formed by laminating prepregs and curing the resin through heating and pressurization. Depending on the shape of the reinforcing fibers, prepregs are classified into unidirectional prepregs and cross prepregs. While thermosetting resins such as epoxy resins are mostly used, thermoplastic resins such as polyetherketone may also be used.

[0003] Prepreg is laminated differently depending on the molding shape. In the case of rod-shaped structures, it is laminated by rolling it around a steel rod called a mandrel, and in the case of plate-shaped structures, prepreg is laminated by attaching it layer by layer to the surface of the mold.

[0004] Prepreg forming processes include various methods such as press forming, sheet rolling, vacuum bag forming, and autoclave forming, depending on the application of heat and pressure. Among these, press forming is used for prepreg compression molding (PCM).

[0005] Registered Patent No. 10-2280820, published on July 23, 2021, relates to “automatic molding control method for prepreg compression molding” and discloses a control method capable of automatically molding by setting molding conditions for an optimal prepreg molded product.

[0006] Registered Patent No. 10-2203198, published on January 14, 2021, relates to a “dual composite molding device” and discloses a dual composite molding device configured to enable press molding and autoclave molding as the receiving body and the first molding table are combined and separated.

[0007] However, an apparatus and method for precisely controlling pressure during prepreg compression molding have not yet been specifically disclosed.

[0008] One objective of the present invention is to provide a prepreg compression molding (PCM) apparatus and method capable of manufacturing a prepreg compression molded product that is uniform and has excellent repeatability.

[0009] Another objective of the present invention is to provide a prepreg compression molding (PCM) apparatus and method capable of manufacturing prepreg compression molded products with high productivity and excellent characteristics.

[0010] Another objective of the present invention is to provide a prepreg compression molding (PCM) apparatus and method capable of preventing bubble defects and manufacturing prepreg compression molded products having excellent characteristics.

[0011] The problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description below.

[0012] According to one aspect of the proposed invention, a prepreg compression molding (PCM) device comprises a support frame, a hydraulic cylinder fixed to one side of the support frame, a pneumatic cylinder fixed to the other side of the support frame corresponding to the side where the hydraulic cylinder is fixed, a hydraulic mold connected to the hydraulic cylinder and moving up and down, a pneumatic mold connected to the pneumatic cylinder and moving up and down, a pneumatic mold support member that restricts the movement of the pneumatic mold toward the pneumatic cylinder, and a control unit that controls the operation of the hydraulic cylinder and the pneumatic cylinder.

[0013] According to an additional aspect, the control unit includes a temperature control unit that controls the temperature of the mold to a preset temperature, a hydraulic control unit that operates a hydraulic cylinder to move the hydraulic side mold to a preset hydraulic reference position or return it to an initial position, and a pneumatic control unit that applies a preset pneumatic pressure to a pneumatic cylinder or removes pneumatic pressure to move the pneumatic side mold or return it to an initial position.

[0014] According to an additional aspect, the control unit includes a speed control unit that controls the movement speed of the hydraulic mold. The speed control unit moves the hydraulic mold at a first speed from an initial position of the hydraulic mold to a first reference position between the initial position of the hydraulic mold and the hydraulic reference position, and moves the hydraulic mold at a second speed from the first reference position to a second reference position between the first reference position and the hydraulic reference position. At this time, the second speed is slower than the first speed.

[0015] According to an additional aspect, the control unit includes a bubble removal unit that removes bubbles from a prepreg molded product by reducing and increasing the gap between the hydraulic side mold and the pneumatic side mold by a predetermined number of repetitions.

[0016] According to an additional aspect, the control unit further includes a profile creation unit that outputs a pressure measured according to the molding time compared with a preset pressure.

[0017] According to another aspect of the proposed invention, a prepreg compression molding (PCM) method comprises a mold temperature control step of controlling the temperature of the mold to a preset temperature, a hydraulic mold movement step of moving a hydraulic mold connected to a hydraulic cylinder to a preset hydraulic reference position by operating a hydraulic cylinder, a pneumatic mold movement step of moving a pneumatic mold connected to a pneumatic cylinder by applying a preset pneumatic pressure to a pneumatic cylinder, a pneumatic mold return step of returning the pneumatic mold to an initial position by removing the pneumatic pressure from the pneumatic cylinder, and a hydraulic mold return step of returning the hydraulic mold to an initial position by operating a hydraulic cylinder.

[0018] According to an additional aspect, the hydraulic mold movement step comprises a first hydraulic mold movement step of moving the hydraulic mold at a first speed from an initial hydraulic mold position to a first reference position between the initial hydraulic mold position and the hydraulic reference position, and a second hydraulic mold movement step of moving the hydraulic mold at a second speed from the first reference position to a second reference position between the first reference position and the hydraulic reference position. In this case, the second speed is slower than the first speed.

[0019] According to an additional aspect, the prepreg compression molding (PCM) method further includes a bubble removal step for removing bubbles from a prepreg molded product by reducing and increasing the gap between the hydraulic side mold and the pneumatic side mold by a predetermined number of repetitions.

[0020] According to an additional aspect, the bubble removal step comprises the step of operating the hydraulic cylinder to move the hydraulic side mold toward the pneumatic side mold, the step of stopping the hydraulic cylinder to fix the position of the hydraulic side mold when the position of the hydraulic side mold reaches a predetermined bubble removal position, and the step of operating the hydraulic cylinder to return the hydraulic side mold when a predetermined bubble removal time has elapsed.

[0021] According to an additional aspect, the prepreg compression molding (PCM) method further includes a pressure profile output step that outputs a pressure measured according to the molding time compared with a preset pressure.

[0022] The prepreg compression molding (PCM) apparatus and method according to the present invention can precisely apply multiple pressures of high pressure and low pressure to a prepreg molded body, thereby enabling the production of a prepreg compression molded product that is uniform and has excellent repeatability.

[0023] The prepreg compression molding (PCM) apparatus and method according to the present invention can manufacture prepreg compression molded products with high productivity and excellent characteristics by operating a hydraulic cylinder at multiple speeds of high and low speeds.

[0024] The prepreg compression molding (PCM) apparatus and method according to the present invention can prevent bubble defects and manufacture prepreg compression molded products with excellent characteristics by adding a bubble removal process.

[0025] FIG. 1 is a front view showing the configuration of a prepreg compression molding (PCM) device according to one embodiment.

[0026] FIG. 2 is a configuration diagram showing the configuration of a control unit of a prepreg compression molding (PCM) device according to one embodiment.

[0027] FIG. 3 is a flowchart illustrating a prepreg compression molding (PCM) method according to one embodiment.

[0028] FIG. 4 is a flowchart showing a bubble removal step in a prepreg compression molding (PCM) method according to one embodiment.

[0029] FIG. 5 is a flowchart showing the hydraulic side mold movement step in a variation of the prepreg compression molding (PCM) method according to one embodiment.

[0030] FIG. 6 is an example graph showing changes in temperature, pressure, and prepreg thickness over time of a prepreg compression molding (PCM) device according to one embodiment.

[0031] FIG. 7 is a photograph showing the shape of a prepreg manufactured by a prepreg compression molding (PCM) apparatus and method according to one embodiment.

[0032] The foregoing and additional aspects are embodied through embodiments described with reference to the attached drawings. It is understood that the components of each embodiment may be combined in various ways within the embodiment or with components of other embodiments, unless otherwise stated or contradicted. Based on the principle that the inventor may appropriately define the concepts of terms to best describe his invention, the terms used in this specification and claims shall be interpreted in a meaning and concept consistent with the description or proposed technical idea.

[0033] In this specification, a module or part may be composed of a processor and memory and a set of program instructions stored in memory so as to be executed on the processor. Additionally, a module or part may be composed using a set of electronic components or circuits, such as an ASIC or FPGA, designed to execute these instructions. Furthermore, the operation of each module or part may be performed by one or more processors or devices.

[0034] Components marked with identical or similar symbols perform identical or similar functions, so their descriptions may be omitted. For components with omitted drawing symbols, reference may be made to the descriptions provided for components with identical or similar symbols.

[0035] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0036] FIG. 1 is a front view showing the configuration of a prepreg compression molding (PCM) device according to one embodiment.

[0037] According to one aspect of the proposed invention, a prepreg compression molding (PCM) device (100) comprises a support frame, a hydraulic cylinder (160), a pneumatic cylinder (190), a hydraulic side mold (150), a pneumatic side mold (130), a pneumatic side mold support member (120), and a control unit (200).

[0038] The support frame secures the hydraulic cylinder (160) and the pneumatic cylinder (190). The support frame includes a hydraulic cylinder support (170), a pneumatic cylinder support (110), and a connecting part (180). The hydraulic cylinder support (170) is configured to be located on one side of the support frame, for example, at the top in FIG. 1. The pneumatic cylinder support (110) is configured to be located on the other side of the support frame opposite to the hydraulic cylinder support (170), for example, at the bottom in FIG. 1. The connecting part (180) connects and secures the hydraulic cylinder support (170) and the pneumatic cylinder support (110).

[0039] The hydraulic cylinder (160) is fixed to a hydraulic cylinder support (170) on one side of the support frame. The hydraulic cylinder is positioned so that its movable part faces the pneumatic cylinder.

[0040] The hydraulic side mold (150) is configured to be connected to the movable part of the hydraulic cylinder so that it can move up and down when the hydraulic cylinder is operated. A pressure gauge (not shown) for measuring the pressure applied to the hydraulic side mold may be further provided.

[0041] The pneumatic cylinder (190) is fixed to a pneumatic cylinder support (110) located on the other side corresponding to one side of the support frame where the hydraulic cylinder is fixed. The pneumatic cylinder is positioned so that its movable part faces the hydraulic cylinder. To provide and control pneumatic pressure to the pneumatic cylinder, an air pipe (195), a valve (not shown), a pressure regulator (not shown), etc. may be further provided.

[0042] The pneumatic side mold (130) is configured to be connected to the movable part of the pneumatic cylinder so that it can move up and down when the pneumatic cylinder is operated.

[0043] Since the movable part of the hydraulic cylinder (160) and the movable part of the pneumatic cylinder (190) face each other, the hydraulic cylinder and the pneumatic cylinder can be operated to reduce the distance between the hydraulic side mold (150) and the pneumatic side mold (130), and pressure can be applied to the prepreg molded body (140) in between to perform compression molding. That is, the prepreg molded body (140) has the hydraulic side mold located at the top and the pneumatic side mold located at the bottom, so that pressure can be transmitted from both sides.

[0044] The pneumatic side mold support member (120) is configured to restrict the movement of the pneumatic side mold toward the pneumatic cylinder. It is preferable that the height of the pneumatic side mold support member (120) be the same as the height of the pneumatic cylinder. The pneumatic side mold support member (120) is provided with a mold support portion (123) capable of supporting the pneumatic side mold at the portion in contact with the pneumatic side mold (130). The pneumatic side mold support member (120) may be configured in a square or circular ring shape to surround the pneumatic cylinder.

[0045] In FIG. 1, when the hydraulic cylinder (160) operates and the hydraulic side mold (150) moves downward, the hydraulic side mold (150) applies pressure to the prepreg molded body (140). At this time, since the pneumatic side mold (130) is fixed to the pneumatic cylinder support member (110) by the pneumatic side mold support member (120), the pressure applied by the hydraulic side mold (150) can be transmitted directly to the prepreg molded body (140).

[0046] In order to compression mold the prepreg, pressure must be applied to the prepreg molded body (140) at a high pressure of tens of bar initially, and then at a low pressure of several bar after a certain period of time, so that the elasticity, strength, and other characteristics of the prepreg after compression molding are excellent and defects such as bubble formation are reduced.

[0047] When using hydraulic cylinders, applying high pressure of tens of bar does not pose a significant problem, but errors may occur when applying low pressure of several bar. Therefore, in order to manufacture a product with high precision and excellent repeatability, it is necessary to use a pneumatic cylinder capable of precisely controlling low pressure.

[0048] For example, when using a 10-ton hydraulic cylinder, a pressure of 70 to 210 bar can be applied to a diameter of 100 mm. If a pressure regulator is set to apply 100 bar, a pressure of 50 bar is applied when the diameter of the prepreg molded product is approximately 200 mm. When using such a high-pressure hydraulic cylinder, it is difficult to control low pressure below 10 bar. Pneumatic cylinders allow for easy pressure control below 10 bar. For example, if the low pressure is 8 bar, setting the pressure of the pneumatic cylinder to 8 bar allows for more precise control of the low pressure than with a high-pressure hydraulic cylinder.

[0049] Since the pneumatic side mold (130) is supported and fixed by the pneumatic side mold support member (120), when the hydraulic cylinder (160) is operated and the hydraulic side mold (150) is lowered, high pressure is applied to the prepreg molded body (140), and the thickness of the prepreg molded body is reduced. The hydraulic side mold (150) can be set to lower until a certain thickness is reached. The operation of the hydraulic cylinder (160) is stopped at a position or time when the prepreg molded body (140) reaches a certain thickness. To this end, a position sensor (155) may be provided. The position sensor (155) may be installed attached to the hydraulic side mold. The position sensor (155) can measure the distance from the pneumatic side mold (130).

[0050] When the hydraulic cylinder (160) stops operating, the prepreg molded body (140) remains in a compressed state, and the pressure applied to the prepreg molded body (140) decreases. In order to apply additional low pressure to the prepreg molded body (140), pneumatic pressure is injected into the pneumatic cylinder (190). When pneumatic pressure is applied to the pneumatic cylinder (190), the pneumatic side mold (130) moves toward the hydraulic side mold (150) and applies additional low pressure to the prepreg molded body (140).

[0051] By using a displacement sensor (not shown) to measure the displacement of the pneumatic cylinder, the thickness of the prepreg molded body to which pressure is applied can be calculated. When the thickness of the prepreg molded body (140) corresponds to the final thickness, the pneumatic pressure of the pneumatic cylinder (190) is released to return the pneumatic side mold (130) to its initial position. When molding is completed, the hydraulic cylinder (160) is activated to return the hydraulic side mold (150) to its initial position as well, preparing for the next operation.

[0052] A protrusion (125) may be formed on the upper end of the support portion (123) of the pneumatic side mold support member (120), and a groove (135) corresponding to the protrusion (125) may be formed in the pneumatic side mold (130). The protrusion (125) is formed to be narrower than the area of ​​the mold support portion (123). The protrusion (125) may be formed in the shape of a plurality of cylinders or may be formed in the shape of a ring. When the pneumatic side mold (130) moves up and down by the pneumatic cylinder (190), the protrusion (125) of the pneumatic side mold support member (120) can prevent movement of the pneumatic side mold (130), thereby enabling the production of a more uniform prepreg compression molded product.

[0053] The control unit (200) controls the operation of the hydraulic cylinder and the pneumatic cylinder. The control unit (200) will be further explained using FIG. 2.

[0054] FIG. 2 is a configuration diagram showing the configuration of a control unit of a prepreg compression molding (PCM) device according to one embodiment.

[0055] According to an additional aspect, the control unit (200) may include an input unit (210) that receives temperature and pressure setting reference data, a storage unit (230) that stores the input data and measured data such as temperature and pressure, and an output unit (220) that outputs the stored data.

[0056] According to an additional aspect, the control unit (200) includes a temperature control unit (240) that controls the temperature of the mold to a preset temperature, a hydraulic control unit (250) that operates a hydraulic cylinder to move the hydraulic side mold to a preset hydraulic reference position or return it to an initial position, and a pneumatic control unit (260) that applies a preset pneumatic pressure to a pneumatic cylinder or removes pneumatic pressure to move the pneumatic side mold or return it to an initial position.

[0057] The temperature control unit (240) heats part or all of the hydraulic side mold (150) or pneumatic side mold (130) to a preset temperature in order to heat the prepreg molded body to a constant temperature. For this purpose, a heater (not shown) may be provided inside the mold. The temperature is configured to be controllable between 50°C and 350°C, which is required for prepreg molding.

[0058] According to an additional aspect, the control unit (200) further includes a speed control unit (255) that controls the movement speed of the hydraulic mold. The speed control unit (255) moves the hydraulic mold at a first speed from the initial position of the hydraulic mold to a first reference position between the initial position of the hydraulic mold and the hydraulic reference position, and moves the hydraulic mold at a second speed from the first reference position to a second reference position between the first reference position and the hydraulic reference position. At this time, the second speed is slower than the first speed. The operation of the speed control unit (255) is further explained with reference to FIG. 5.

[0059] According to an additional aspect, the control unit (200) further includes a displacement measuring unit (265). The displacement measuring unit (265) receives a signal measured from a displacement sensor (not shown) and calculates the displacement of the pneumatic side mold (130). Additionally, the distance between the hydraulic side mold (150) and the pneumatic side mold (130), which are stopped at a hydraulic reference position, can be calculated to determine the thickness of the prepreg molded body. The displacement measuring unit (265) determines the return of the pneumatic side mold (130) based on the displacement of the pneumatic side mold (130), the distance between the hydraulic side mold and the pneumatic side mold, or the thickness of the prepreg molded body.

[0060] According to an additional aspect, the control unit includes a bubble removal unit (270) that removes bubbles from a prepreg molded product by reducing and increasing the gap between the hydraulic side mold and the pneumatic side mold by a predetermined number of repetitions. The operation of the bubble removal unit (270) will be described later with reference to FIG. 4.

[0061] According to an additional aspect, the control unit further includes a profile creation unit (280) that compares a pressure measured according to the molding time with a preset pressure and outputs it. The profile creation unit (280) can output temperature, pressure, and thickness data over time as shown in FIG. 6.

[0062] FIG. 3 is a flowchart illustrating a prepreg compression molding (PCM) method according to one embodiment.

[0063] According to another aspect of the proposed invention, a prepreg compression molding (PCM) method comprises a mold temperature control step (S320) for controlling the temperature of the mold to a preset temperature, and a hydraulic mold movement step (S330) for operating a hydraulic cylinder to move the hydraulic mold connected to the hydraulic cylinder to a preset hydraulic reference position. The hydraulic reference position is checked based on the driving time or position sensor (S340), and if it corresponds to the hydraulic reference position, the driving of the hydraulic cylinder is stopped (S350).

[0064] The prepreg compression molding (PCM) method further includes a pneumatic mold movement step (S360) in which a preset pneumatic pressure is applied to a pneumatic cylinder to move the pneumatic mold connected to the pneumatic cylinder. A measurement value of a displacement sensor corresponding to the thickness of the prepreg molded body is compared with a reference displacement value (S370), and if it becomes larger than the reference displacement, the pneumatic pressure is removed (S380). That is, the prepreg compression molding (PCM) method further includes a pneumatic mold return step (S380) in which the pneumatic pressure of the pneumatic cylinder is removed to return the pneumatic mold to its initial position.

[0065] The prepreg compression molding (PCM) method includes a hydraulic mold return step (S390) in which a hydraulic cylinder is operated to return the hydraulic mold to an initial position in preparation for the next product.

[0066] According to an additional aspect, the prepreg compression molding (PCM) method may further include a bubble removal step (S310). It is preferable to perform the bubble removal step (S310) before starting compression molding. The bubble removal step (S310) is explained using FIG. 4.

[0067] According to an additional aspect, the prepreg compression molding (PCM) method further includes a pressure profile output step (S395) that outputs a pressure measured according to the molding time compared with a preset pressure. The pressure profile can be output as, for example, as shown in (b) of FIG. 6.

[0068] FIG. 4 is a flowchart showing a bubble removal step in a prepreg compression molding (PCM) method according to one embodiment.

[0069] According to an additional aspect, the prepreg compression molding (PCM) method further includes a bubble removal step (S310) for removing bubbles from a prepreg molded product by reducing and increasing the gap between the hydraulic side mold and the pneumatic side mold by a predetermined number of repetitions.

[0070] According to an additional aspect, the bubble removal step (S310) includes the step of operating the hydraulic cylinder to move the hydraulic side mold toward the pneumatic side mold (S430), the step of stopping the hydraulic cylinder to fix the position of the hydraulic side mold when the position of the hydraulic side mold reaches a predetermined bubble removal position (S450), and the step of operating the hydraulic cylinder to return the hydraulic side mold when a predetermined bubble removal time has elapsed (S470).

[0071] Referring to FIG. 4, a more detailed embodiment is described as follows: the bubble removal step (S310) first sets a temperature suitable for bubble removal (S410). Bubble removal can be performed at a temperature of about 50°C, which is relatively lower than the compression molding temperature of the prepreg molded product.

[0072] If necessary, the air pressure can be set (S420) to perform the bubble removal operation while low pressure is applied to the air-pressure side mold.

[0073] The hydraulic cylinder is operated to lower the hydraulic mold (S430), and it is checked whether the position of the hydraulic mold reaches a predetermined reference position, which is the bubble removal position (S440). A position sensor can be used to configure the lowering to stop automatically when a certain position is reached (S450).

[0074] When the bubble removal position is reached, the mold is maintained in a stationary state for a predetermined holding time, which is the bubble removal time (S460). Once the holding time has elapsed, the hydraulic cylinder is activated to raise the hydraulic side mold back up and return it to its original position (S470). At this time, the return position may be lower than the initial position before the bubble removal process is completely finished. This is intended to improve productivity through rapid repetition.

[0075] The hydraulic side mold is repeatedly lowered and raised using a hydraulic cylinder until a predetermined number of repetitions is reached (S480). When bubble removal has been performed for the number of repetitions, a prepreg compression molding process is performed (S490).

[0076] For example, as a result of repeating the experiment 5 times by applying a pressure of about 20 bar at about 50°C for a holding time of 3 seconds before performing the prepreg compression molding process, it was confirmed that bubbles were effectively removed during actual molding, as shown in Figure 7 (b).

[0077] FIG. 5 is a flowchart showing the hydraulic side mold movement step in a variation of the prepreg compression molding (PCM) method according to one embodiment.

[0078] According to an additional aspect, the hydraulic mold movement step (S330) includes a hydraulic mold first movement step (S530) and a hydraulic mold second movement step (S540). The hydraulic mold first movement step (S530) moves the hydraulic mold at a first speed until it reaches a first reference position from the initial position of the hydraulic mold (S535). The first reference position is set between the initial position of the hydraulic mold and the hydraulic reference position. The hydraulic mold second movement step (S540) moves the hydraulic mold at a second speed until it reaches a second reference position from the first reference position (S545). The second reference position is set between the first reference position and the hydraulic reference position. The second reference position can be set to be the same as the hydraulic reference position. In this case, it is preferable to set the second speed slower than the first speed. That is, pressure is applied to the mold body at a high speed initially, and then pressure is applied slowly at a low speed thereafter. When the hydraulic reference position is the second reference position, the hydraulic cylinder is deactivated (S550).

[0079] FIG. 6 is an example graph showing changes in temperature, pressure, and prepreg thickness over time of a prepreg compression molding (PCM) device according to one embodiment.

[0080] Figure 6 (a) is a graph showing an example of the mold temperature of a prepreg compression molding (PCM) device over time.

[0081] Figure 6(b) is a graph showing an example of pressure change of a prepreg compression molding (PCM) device over time. The thick line represents the set value, and the dotted line represents an example of the actual measured value when the operation is performed according to the set value.

[0082] Figure 6 (c) is an example graph showing the thickness of a prepreg molded body over time. The thickness of the prepreg molded body can be calculated using the distance between the hydraulic side mold and the pneumatic side mold.

[0083] FIG. 7 is a photograph showing the shape of a prepreg manufactured by a prepreg compression molding (PCM) apparatus and method according to one embodiment.

[0084] Figure 7 (a) shows the appearance of a prepreg molded body with bubble defects, and Figure 7 (b) shows the appearance of a normal prepreg molded body without bubble defects.

[0085] In FIG. 7 (a), the horizontal curved portion (710) is the part marked with a pen to identify bubble defects. Multiple bubbles (730) can be seen in the marked portion.

[0086] FIG. 7(b) is a photograph of a prepreg molded body in which the bubble removal process described using FIG. 4 is added. Referring to FIG. 7(b), bubble defects cannot be observed in the prepreg compression molded body to which the bubble removal method (S310) according to one embodiment of the present invention is applied. Therefore, it can be seen that the bubble removal method (S310) according to one embodiment has the effect of preventing bubble defects.

[0087] Although the present invention has been described above with reference to embodiments with reference to the accompanying drawings, it is not limited thereto and should be interpreted to encompass various variations that can be obviously derived from them by those skilled in the art. The claims are intended to encompass such variations.

[0088] The present invention has industrial applicability as a technology used for prepreg compression molding.

Claims

1. In the prepreg compression molding (PCM) method, Mold temperature control step for controlling the mold temperature to a preset temperature; A hydraulic mold movement step of operating a hydraulic cylinder to move a hydraulic mold connected to the hydraulic cylinder to a preset hydraulic reference position; A pneumatic mold movement step of moving a pneumatic mold connected to a pneumatic cylinder by applying a preset pneumatic pressure to the pneumatic cylinder; A pneumatic side mold return step for returning the pneumatic side mold to its initial position by removing the pneumatic pressure from the pneumatic cylinder; and A hydraulic mold return step comprising operating a hydraulic cylinder to return the hydraulic mold to its initial position; Prepreg compression molding (PCM) method.

2. In Paragraph 1, The above hydraulic mold movement step is, A first hydraulic mold movement step for moving the hydraulic mold at a first speed from an initial hydraulic mold position to a first reference position between the initial hydraulic mold position and the hydraulic reference position; and A second hydraulic mold movement step for moving the hydraulic mold at a second speed from the first reference position to a second reference position between the first reference position and the hydraulic reference position; The above second speed is slower than the above first speed, Prepreg compression molding (PCM) method.

3. In Paragraph 1, A bubble removal step further comprising reducing and increasing the gap between the hydraulic side mold and the pneumatic side mold by a predetermined number of repetitions to remove bubbles from the prepreg molded product. Prepreg compression molding (PCM) method.

4. In Paragraph 3, The above bubble removal step is, A step of operating the hydraulic cylinder to move the hydraulic side mold toward the pneumatic side mold; When the position of the hydraulic mold reaches a predetermined bubble removal position, the step of stopping the hydraulic cylinder to fix the position of the hydraulic mold; and A step comprising: activating the hydraulic cylinder to return the hydraulic side mold when a predetermined bubble removal time has elapsed; Prepreg compression molding (PCM) method.

5. In Paragraph 1, A pressure profile output step that outputs a pressure measured according to the molding time by comparing it with a preset pressure; further comprising Prepreg compression molding (PCM) method.

6. In a prepreg compression molding (PCM) device, Support frame; A hydraulic cylinder fixed to one side of the above support frame; A pneumatic cylinder fixed to the other side corresponding to the one side where the hydraulic cylinder of the support frame is fixed; A hydraulic mold connected to the above hydraulic cylinder and moving up and down; A pneumatic mold connected to the above pneumatic cylinder and moving up and down; A pneumatic mold support member that restricts the movement of the above pneumatic mold toward the above pneumatic cylinder; and A control unit for controlling the operation of the above hydraulic cylinder and the above pneumatic cylinder; comprising Prepreg compression molding (PCM) device.

7. In Paragraph 6, The above control unit is, A temperature control unit that controls the temperature of the mold to a preset temperature; A hydraulic control unit that operates a hydraulic cylinder to move the hydraulic side mold to a preset hydraulic reference position or return it to an initial position; and A pneumatic control unit that applies a preset pneumatic pressure to a pneumatic cylinder or removes pneumatic pressure to move the pneumatic side mold or return it to an initial position; Prepreg compression molding (PCM) device.

8. In Paragraph 7, The above control unit is, A speed control unit for controlling the movement speed of the above hydraulic mold; is included, The above speed control unit is, Moving the hydraulic mold at a first speed from the initial position of the hydraulic mold to a first reference position between the initial position of the hydraulic mold and the hydraulic reference position, and Moving the hydraulic mold at a second speed from the first reference position to a second reference position between the first reference position and the hydraulic reference position, and The above second speed is slower than the above first speed, Prepreg compression molding (PCM) device.

9. In Paragraph 6, The above control unit is, A bubble removal unit that removes bubbles from a prepreg molded product by reducing and increasing the gap between the hydraulic side mold and the pneumatic side mold by a predetermined number of repetitions; Prepreg compression molding (PCM) device.

10. In Paragraph 6, The above control unit is, A profile creation unit that outputs a pressure measured according to molding time by comparing it with a preset pressure; Prepreg compression molding (PCM) device.

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