A carbon fiber shell forming device and method for musical instrument production

Abstract

The present application provides a carbon fiber shell forming device and method for musical instrument production, belonging to the technical field of musical instrument production and processing, including a male mold, a female mold installed directly above the male mold, and a vacuum extraction tube penetrating through the bottom of the male mold; the female mold is composed of a lifting seat, a frame-shaped side mold, and a column-shaped top mold. The lifting seat is vertically slidably connected directly above the male mold. Both the frame-shaped side mold and the column-shaped top mold are vertically slidably connected inside the lifting seat through elastic members. The inner cavity of the frame-shaped side mold consists of a sliding sleeve cavity that fits with the column-shaped top mold and a side mold cavity that fits with the carbon fiber shell. There is a material extrusion gap reserved between the bottom edge of the sliding sleeve cavity and the corner edge of the inner top wall of the side mold cavity; a locking member matching the frame-shaped side mold is provided on the lifting seat; the present application can reduce the probability of excessive accumulation of resin on the upper surface of the carbon fiber shell.

Description

Technical Field

[0001] This application relates to the technical field of musical instrument production and processing, and particularly relates to a carbon fiber outer shell forming device and method for musical instrument production. Background Art

[0002] Carbon fiber is a lightweight, strong, and durable material that also has excellent impact resistance and environmental adaptability. The musical instrument outer shell made of carbon fiber can improve portability while providing effective protection for the internal parts of the musical instrument, and can also ensure that the sound quality of the musical instrument is not affected by the external environment. Therefore, carbon fiber outer shells have been widely used in musical instrument manufacturing.

[0003] Currently, the production and forming of carbon fiber outer shells are generally completed by the method of compression molding. In this method, personnel need to first adhere the carbon fiber material fully pre-impregnated with resin to the male mold to form the initial shape of the carbon fiber outer shell, and then buckle the female mold on the male mold to hot press the carbon fiber outer shell, so that the excess resin in the carbon fiber outer shell is extruded and a flash is formed at the bottom of the formed carbon fiber outer shell. Referring to the Chinese patent application document with the publication number CN117325484A, the publication date of January 2, 2024, and the name of a forming device and forming method for a carbon fiber composite material, which includes an upper module and a lower module, can completely extract the air inside the carbon fiber prepreg and form a vacuum state during the forming process to prevent bubbles from being generated in the carbon fiber prepreg during hot pressing.

[0004] Referring to the above technical solution, limited by the shape of some musical instruments, when the female mold is buckled on the male mold to extrude the carbon fiber outer shell, the upper surface of the carbon fiber outer shell will be directly pressured by the female mold, while the side surface of the carbon fiber outer shell will not be directly pressured by the female mold. Since the fluidity of the resin itself is poor, its penetration rate in the carbon fiber outer shell will also be affected to a certain extent. Therefore, when the excess resin on the upper surface of the carbon fiber outer shell is extruded outward, due to the blockage of the side wall of the female mold, the excess resin is likely to accumulate excessively between the top wall of the female mold and the upper surface of the carbon fiber outer shell, which may lead to uneven resin distribution on the upper surface and side surface of the carbon fiber outer shell, thereby affecting the final quality of the carbon fiber outer shell. Summary of the Invention

[0005] In view of this, this application provides a carbon fiber outer shell forming device and method for musical instrument production, mainly used to solve the problem that the excess accumulation of resin on the upper surface of the carbon fiber outer shell affects the final quality of the carbon fiber outer shell.

[0006] To solve the above technical problems, this application provides a carbon fiber outer shell forming device and method for musical instrument production.

[0007] In a first aspect, the present application provides a carbon fiber shell forming device for musical instrument production, including a male mold, a female mold installed directly above the male mold, and a vacuum extraction tube penetrating through the bottom of the male mold; the female mold is composed of a lifting seat, a frame-shaped side mold, and a column-shaped top mold. The lifting seat is vertically slidably connected directly above the male mold. Both the frame-shaped side mold and the column-shaped top mold are vertically slidably connected inside the lifting seat through elastic members. The inner cavity of the frame-shaped side mold consists of a sliding sleeve cavity that fits with the column-shaped top mold and a side mold cavity that fits with the carbon fiber shell. There is a material extrusion gap reserved between the bottom edge of the sliding sleeve cavity and the corner edge of the inner top wall of the side mold cavity; a locking member matching the frame-shaped side mold is provided on the lifting seat for locking or unlocking the height of the frame-shaped side mold on the lifting seat.

[0008] By adopting the above technical solution, the lifting seat, the frame-shaped side mold, and the column-shaped top mold move down in batches, which can avoid excessive accumulation of resin on the upper surface of the carbon fiber shell to a certain extent, and make the resin evenly distributed on the upper surface and the side surface of the carbon fiber shell.

[0009] Optionally, the bottom edge of the frame-shaped side mold is inclined downward from top to bottom towards the direction close to the vertical central axis of the frame-shaped side mold.

[0010] By adopting the above technical solution, it is beneficial to the resin pushing work and the subsequent flash removal work.

[0011] Optionally, the male mold, the frame-shaped side mold, and the column-shaped top mold are all made of aluminum alloy mold.

[0012] By adopting the above technical solution, utilizing the high thermal conductivity of the aluminum alloy material, using the male mold, the frame-shaped side mold, and the column-shaped top mold as heat conduction media can make the entire carbon fiber shell evenly heated.

[0013] Optionally, the locking member includes a supporting plate slidably connected inside the lifting seat and capable of supporting the frame-shaped side mold.

[0014] By adopting the above technical solution, the position of the frame-shaped side mold inside the lifting seat can be locked.

[0015] Optionally, a sealing ring is provided at the edge of the upper surface of the male mold for sealing the inner cavities of the female mold and the male mold when they are buckled.

[0016] By adopting the above technical solution, the sealing ring can seal the inner cavities of the female mold and the male mold when they are buckled to prevent the vacuum environment from being damaged.

[0017] In a second aspect, the present application provides a carbon fiber shell forming method for musical instrument production, which is applied to the carbon fiber shell forming device for musical instrument production described in the first aspect. The forming method includes:

[0018] S1. First, fully pre-impregnate the carbon fiber material in the resin, and then the operator adheres the carbon fiber material to the male mold with reference to the male mold to form the initial shape of the carbon fiber shell.

[0019] S2. Clamp the female mold on the male mold, and use an external heating device to heat the female mold and the male mold to complete the hot pressing of the carbon fiber shell, so that the excess resin in the carbon fiber shell is extruded. At the same time, an external vacuum pump, in cooperation with the vacuum tube, evacuates the air in the inner cavities of the female mold and the male mold to form a vacuum environment.

[0020] S3. After the hot pressing of the carbon fiber shell is completed, separate the female mold from the male mold and complete the demolding of the carbon fiber shell.

[0021] By adopting the above technical solution, the forming work of the carbon fiber shell can be completed quickly, and at the same time, the final forming quality of the carbon fiber shell can be guaranteed.

[0022] Optionally, in S2, when the female mold is clamped on the male mold, the frame side mold should be locked at the highest position of the lifting seat through the cooperation of the locking parts. Then the lifting seat moves downward preferentially to be clamped with the male mold. Subsequently, the columnar top mold moves downward under external pressure to extrude the upper surface of the carbon fiber shell. Then the locking of the frame side mold by the locking parts is released. Finally, the frame side mold moves downward again under external pressure to contact the side surface of the carbon fiber shell.

[0023] By adopting the above technical solution, it is possible to prevent the resin from accumulating excessively on the upper surface of the carbon fiber shell, and at the same time, the excess resin extruded from the upper surface of the carbon fiber shell can fill the possible gaps on the side surface of the carbon fiber shell.

[0024] Optionally, in S3, the external vacuum pump and the vacuum tube cooperate again to send cold air into the inner cavities of the female mold and the male mold, accelerating the cooling and curing of the carbon fiber shell while relieving the vacuum state of the two inner cavities.

[0025] By adopting the above technical solution, injecting cold air during demolding accelerates the cooling of the carbon fiber shell, which is beneficial to the development of the demolding work.

[0026] In summary, compared with the prior art, the present application includes at least one of the following beneficial technical effects:

[0027] 1. Adopting the design of the split female mold, applying pressure to different areas of the carbon fiber shell in stages when the female mold is clamped on the male mold can reduce the probability of excessive resin accumulation on the upper surface of the carbon fiber shell, and at the same time can fill the possible gaps on the side surface of the carbon fiber shell, thereby improving the final forming quality of the carbon fiber shell.

[0028] 2. The concave die and convex die made of high - thermal - conductivity materials are used as heat - conducting media. When heating the carbon fiber shell, heat transfer can be carried out by using the concave die and convex die that perfectly fit the carbon fiber shell, enabling the overall heating of the carbon fiber shell to be more uniform.

[0029] 3. During the demolding process, the vacuum state of the inner cavity formed by the concave die and convex die is released by introducing cold air, which can accelerate the cooling and solidification of the carbon fiber shell. Moreover, as the cold air continues to be introduced, the air pressure in the inner cavity formed by the concave die and convex die will gradually increase, which is beneficial to the separation of the concave die and convex die to complete demolding. Description of the Drawings

[0030] Figure 1 It is a schematic structural diagram of a carbon fiber shell forming device for musical instrument production in this application;

[0031] Figure 2 It is a cross - sectional view of the convex die and concave die in this application;

[0032] Figure 3 It is a cross - sectional view of the frame - type side die in this application;

[0033] Figure 4 It is a cross - sectional view of the frame - type side die and column - type top die in this application;

[0034] Figure 5 It is a cross - sectional view of the convex die in this application;

[0035] Figure 6 It is a schematic structural diagram of the frame - type side die and the supporting plate in this application.

[0036] Description of the reference numerals: 1. Convex die; 11. Vacuum extraction pipe; 2. Concave die; 21. Lifting seat; 22. Frame - type side die; 221. Sliding sleeve cavity; 222. Side die cavity; 223. Extrusion gap; 23. Column - type top die; 24. Elastic member; 3. Locking member; 31. Supporting plate; 4. Sealing ring; 5. Carbon fiber shell. Detailed Embodiments

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below in conjunction with the Figures 1-6 of the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. Based on the described embodiments of this application, all other embodiments obtained by those of ordinary skill in the art belong to the scope protected by this application.

[0038] In the first aspect, this application provides a carbon fiber shell forming device for musical instrument production, adopting the following technical solutions:

[0039] Refer to Figure 1 .Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 , this embodiment provides a carbon fiber shell forming device for musical instrument production, including a male mold 1, a female mold 2 installed directly above the male mold 1, and a vacuum extraction tube 11 penetrating through the bottom of the male mold 1.

[0040] Among them, the female mold 2 is composed of a lifting seat 21, a frame-shaped side mold 22, and a column-shaped top mold 23. The lifting seat 21 is vertically slidably connected directly above the male mold 1. Both the frame-shaped side mold 22 and the column-shaped top mold 23 are vertically slidably connected inside the lifting seat 21 through elastic members 24. The inner cavity of the frame-shaped side mold 22 is composed of a sliding sleeve cavity 221 that fits with the column-shaped top mold 23 and a side mold cavity 222 that fits with the carbon fiber shell 5. There is an extrusion material gap 223 reserved between the bottom edge of the sliding sleeve cavity 221 and the corner edge of the inner top wall of the side mold cavity 222.

[0041] A locking member 3 matching the frame-shaped side mold 22 is provided on the lifting seat 21 for locking or unlocking the height of the frame-shaped side mold 22 on the lifting seat 21.

[0042] First, with the male mold 1 as a reference, the carbon fiber material fully pre-impregnated in the resin is adhered to the male mold 1, so that the impregnated carbon fiber material forms the initial shape of the carbon fiber shell 5 on the male mold 1. Then, the female mold 2 is buckled on the male mold 1. During this process, the frame-shaped side mold 22 is locked at the highest position of the lifting seat 21 due to the cooperation of the locking member 3. After the lifting seat 21 moves down and is buckled with the male mold 1, the external vacuum pump, in cooperation with the vacuum extraction tube 11, evacuates the air in the inner cavities of the lifting seat 21 and the male mold 1 to form a vacuum environment.

[0043] Subsequently, through external pressure, the column-shaped top mold 23 moves down prior to the frame-shaped side mold 22, so that the column-shaped top mold 23 extrudes the upper surface of the carbon fiber shell 5. At this time, the excess resin on the upper surface of the carbon fiber shell 5 will be squeezed towards the edge of the upper surface of the carbon fiber shell 5 and is vertically corresponding to the extrusion material gap 223.

[0044] Then the locking member 3 releases the locking of the frame side mold 22, and then the frame side mold 22 is moved downward by external pressure until the frame side mold 22 contacts the side of the carbon fiber shell 5. In this process, the frame side mold 22 will push the excess resin extruded from the upper surface of the carbon fiber shell 5 downward, and due to the existence of the extrusion gap 223, a small amount of excess resin will remain in the extrusion gap 223. When the corner of the top wall inside the side mold cavity 222 contacts the carbon fiber shell 5, the excess resin in the extrusion gap 223 will be vertically pressed by the corner of the top wall inside the side mold cavity 222. Since the upper surface of the carbon fiber shell 5 has been pressed by the column top mold 23, the excess resin in the extrusion gap 223 can only penetrate downward along the side of the carbon fiber shell 5 after being pressed, so as to fill the gap that may exist on the side of the carbon fiber shell 5, reduce the probability of excessive accumulation of resin on the upper surface of the carbon fiber shell 5, and thus improve the final molding quality of the carbon fiber shell 5.

[0045] After the carbon fiber shell 5 is formed, the external vacuum pump and the vacuum tube 11 cooperate again to send cold air into the inner cavity of the lifting seat 21 and the punch 1, thereby releasing the vacuum state of the inner cavities of the two and accelerating the cooling and solidification of the carbon fiber shell 5. When the cold air is injected, the frame side mold 22 and the columnar top mold 23 will move upward under the action of air pressure and the elastic member 24, separate from the carbon fiber shell 5 and complete demolding.

[0046] Reference Figure 2 and Figure 3 The bottom edge of the frame side mold 22 is inclined from top to bottom toward the direction close to the vertical center axis of the frame side mold 22.

[0047] During the downward movement of the frame side mold 22, the inclined bottom edge of the frame side mold 22 is conducive to the resin pushing work, and when the frame side mold 22 reaches the lowest point, it can produce an indentation on the flash at the bottom of the carbon fiber shell 5, which is conducive to the subsequent flash removal work.

[0048] Reference Figure 1 and Figure 2 The punch 1, the frame side mold 22 and the column top mold 23 are all aluminum alloy molds.

[0049] Due to the high thermal conductivity of the aluminum alloy material itself, when heating the carbon fiber shell 5, the punch 1, the frame side mold 22 and the column top mold 23 that are completely consistent with the carbon fiber shell 5 can be used for heat conduction, so that the carbon fiber shell 5 can be evenly heated as a whole.

[0050] Reference Figure 1 and Figure 6 The locking member 3 includes a supporting plate 31 , which is slidably connected to the inside of the lifting seat 21 and can support the frame-type side mold 22 .

[0051] When the frame side mold 22 is adjusted by personnel to the highest position of the lifting seat 21, the personnel can move the supporting plate 31 towards the direction close to the frame side mold 22, so that the frame side mold 22 is placed on the supporting plate 31 and cannot move downwards; conversely, when the personnel move the supporting plate 31 towards the direction away from the frame side mold 22, the frame side mold 22 can vertically move downwards inside the lifting seat 21 due to its own gravity and the action of external pressure.

[0052] Referring to Figure 4 and Figure 5 , a sealing ring 4 is arranged at the edge of the upper surface of the convex mold 1 for sealing the inner cavities of the concave mold 2 and the convex mold 1 when they are buckled.

[0053] The implementation principle of the carbon fiber shell forming device for musical instrument production in the embodiment of the present application is as follows:

[0054] The personnel first adhere the carbon fiber material fully pre-impregnated in the resin to the convex mold 1 with the convex mold 1 as a reference, so that the impregnated carbon fiber material forms the initial shape of the carbon fiber shell 5 on the convex mold 1, and then buckle the concave mold 2 on the convex mold 1. During this process, the frame side mold 22 is locked at the highest position of the lifting seat 21 due to the cooperation of the locking member 3. After the lifting seat 21 moves down and buckles with the convex mold 1, the external vacuum pump evacuates the air in the inner cavities of the lifting seat 21 and the convex mold 1 with the cooperation of the vacuum extraction pipe 11 to form a vacuum environment.

[0055] Subsequently, through external pressure, the columnar top mold 23 moves down prior to the frame side mold 22, so that the columnar top mold 23 extrudes the upper surface of the carbon fiber shell 5. At this time, the excess resin on the upper surface of the carbon fiber shell 5 will be squeezed towards the edge of the upper surface of the carbon fiber shell 5 and vertically correspond to the material extrusion gap 223.

[0056] Then the locking member 3 releases the locking of the frame side mold 22, and then through external pressure, the frame side mold 22 moves down until the frame side mold 22 contacts the side surface of the carbon fiber shell 5. During this process, the frame side mold 22 will push down the excess resin extruded from the upper surface of the carbon fiber shell 5. And due to the existence of the material extrusion gap 223, a small part of the excess resin will remain in the material extrusion gap 223. When the corner of the inner top wall of the side mold cavity 222 contacts the carbon fiber shell 5, the excess resin in the material extrusion gap 223 will be vertically pressed by the corner of the inner top wall of the side mold cavity 222. Since the upper surface of the carbon fiber shell 5 has been pressed by the columnar top mold 23, the excess resin in the material extrusion gap 223 can only penetrate downward along the side surface of the carbon fiber shell 5 after being pressed, so as to fill the possible gaps on the side surface of the carbon fiber shell 5, reduce the probability of excessive accumulation of resin on the upper surface of the carbon fiber shell 5, and further improve the final forming quality of the carbon fiber shell 5.

[0057] After the carbon fiber outer shell 5 is formed, the external vacuum pump and the vacuum extraction pipe 11 cooperate again to send cold air into the inner cavities of the lifting seat 21 and the punch 1. While relieving the vacuum state of the two inner cavities, the carbon fiber outer shell 5 is cooled and solidified at an accelerated rate. When the cold air is injected, the frame side mold 22 and the column top mold 23 will move upward under the action of air pressure and the elastic member 24 and separate from the carbon fiber outer shell 5 to complete demolding.

[0058] Second, the present application provides a method for forming a carbon fiber outer shell for musical instrument production, which is applied to a device for forming a carbon fiber outer shell for musical instrument production in the first aspect. The forming method includes:

[0059] S1. First, fully pre-impregnate the carbon fiber material in the resin, and then the operator adheres the carbon fiber material to the punch 1 with reference to the punch 1 to form the initial shape of the carbon fiber outer shell 5.

[0060] S2. Fasten the female mold 2 to the punch 1, and heat the female mold 2 and the punch 1 through an external heating device to complete the hot pressing work on the carbon fiber outer shell 5, so that the excess resin in the carbon fiber outer shell 5 is extruded. At the same time, the external vacuum pump, in cooperation with the vacuum extraction pipe 11, evacuates the air in the inner cavities of the female mold 2 and the punch 1 and forms a vacuum environment.

[0061] S3. After the hot pressing of the carbon fiber outer shell 5 is completed, separate the female mold 2 from the punch 1 and complete the demolding of the carbon fiber outer shell 5.

[0062] In S2, when the female mold 2 is fastened to the punch 1, the frame side mold 22 should be locked at the highest position of the lifting seat 21 through the cooperation of the locking member 3. Then, the lifting seat 21 preferentially moves downward to fasten to the punch 1. Subsequently, the column top mold 23 moves downward through external pressure to extrude the upper surface of the carbon fiber outer shell 5. Then, the locking member 3 releases the locking of the frame side mold 22. Finally, the frame side mold 22 moves downward again through external pressure to contact the side surface of the carbon fiber outer shell 5.

[0063] In S3, the external vacuum pump and the vacuum extraction pipe 11 cooperate again to be able to send cold air into the inner cavities of the female mold 2 and the punch 1. While relieving the vacuum state of the two inner cavities, the carbon fiber outer shell 5 is cooled and solidified at an accelerated rate.

[0064] In addition, it should be noted that in the description of the present application, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0065] The above are the preferred embodiments of the present application. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A carbon fiber shell molding device for musical instrument production, comprising a male mold (1), a female mold (2) installed directly above the male mold (1), and a vacuum tube (11) penetrating through the bottom of the male mold (1), characterized in that: The female mold (2) is composed of a lifting seat (21), a frame-type side mold (22) and a column-type top mold (23); the lifting seat (21) is vertically slidably connected to the top of the male mold (1); the frame-type side mold (22) and the column-type top mold (23) are vertically slidably connected to the inside of the lifting seat (21) through an elastic member (24); the inner cavity of the frame-type side mold (22) is composed of a sleeve cavity (221) that matches the column-type top mold (23) and a side mold cavity (222) that matches the carbon fiber shell (5); an extrusion gap (223) is reserved between the bottom edge of the sleeve cavity (221) and the corner edge of the top wall of the side mold cavity (222); the extrusion gap (223) and the column-type top mold (23) are staggered in the horizontal direction; The lifting seat (21) is provided with a locking member (3) matching the frame-type side mold (22) and used for locking the height of the frame-type side mold (22) on the lifting seat (21) or unlocking the frame-type side mold (22).

2. The carbon fiber shell molding device for musical instrument production according to claim 1, characterized in that: The bottom edge of the frame-type side mold (22) is arranged to be inclined from top to bottom in a direction close to the vertical center axis of the frame-type side mold (22).

3. The carbon fiber shell molding device for musical instrument production according to claim 1, characterized in that: The male mold (1), the frame-type side mold (22) and the column-type top mold (23) are all aluminum alloy molds.

4. The carbon fiber shell molding device for musical instrument production according to claim 1, characterized in that: The locking member (3) comprises a supporting plate (31) which is slidably connected to the inside of the lifting seat (21) and is capable of supporting the frame-type side mold (22).

5. The carbon fiber shell molding device for musical instrument production according to claim 1, characterized in that: A sealing ring (4) is provided at the edge of the upper surface of the male mold (1) for sealing the inner cavities of the female mold (2) and the male mold (1) when they are buckled together.

6. A method for molding a carbon fiber shell for musical instrument production, applied to the carbon fiber shell molding device for musical instrument production according to claim 1, the molding method comprising: S1, firstly fully pre-impregnate the carbon fiber material in the resin, and then adhere the carbon fiber material to the convex mold (1) with the convex mold (1) as a reference to form the initial shape of the carbon fiber shell (5); S2, the concave mold (2) is buckled onto the convex mold (1), and the temperature of the concave mold (2) and the convex mold (1) is increased by an external heating device to complete the hot pressing of the carbon fiber shell (5), so that the excess resin in the carbon fiber shell (5) is squeezed out, and at the same time, the external vacuum pump, in cooperation with the vacuum pumping tube (11), extracts the air in the inner cavity of the concave mold (2) and the convex mold (1) to form a vacuum environment; S3, after the hot pressing of the carbon fiber shell (5) is completed, the concave mold (2) and the convex mold (1) are separated and the carbon fiber shell (5) is demoulded.

7. A method for forming a carbon fiber shell for musical instrument production according to claim 6, characterized in that: In S2, when the female mold (2) and the male mold (1) are engaged, the frame-type side mold (22) should be locked at the highest position of the lifting seat (21) through the cooperation of the locking member (3), and then the lifting seat (21) should be moved down first to engage with the male mold (1), and then the column-type top mold (23) is moved down by external pressure and squeezes the upper surface of the carbon fiber shell (5), and then the locking member (3) releases the lock on the frame-type side mold (22), and finally the frame-type side mold (22) is moved down again by external pressure and contacts the side of the carbon fiber shell (5).

8. The method for forming a carbon fiber shell for musical instrument production according to claim 6, characterized in that: In S3, the external vacuum pump and the vacuum tube (11) cooperate again to deliver cold air into the inner cavities of the concave mold (2) and the convex mold (1), thereby relieving the vacuum state of the inner cavities of the two and accelerating the cooling and solidification of the carbon fiber shell (5).

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