TW201406531A - Manufacturing method of hollow carbon fiber formed product and forming mold thereof - Google Patents

Abstract

The present invention provides a manufacturing method of hollow carbon fiber formed product and a forming mold thereof, which comprise: a forming step of wax mold to make a wax mold beforehand according to the interior and exterior configuration of a carbon fiber formed product; a forming step of carbon fiber blank to wind the exterior of wax mold with carbon fiber filament or to wrap with carbon fiber prepreg to make a carbon fiber blank; a mold-placing step to place the carbon fiber blank in a forming mold, the forming mold comprising an upper mold, a lower mold, and a side mold; a forming step to proceed hot press forming to the carbon fiber blank with the forming mold, so that the upper mold, the lower mold, and the side mold apply the upward, downward, and lateral pressure to the carbon fiber blank, while matched with the support of the interior wax mold, making the carbon fiber blank formed into the carbon fiber formed product in the mold; and a taking out step of wax mold to drill a flow-guiding hole for wax on the carbon fiber formed product, then hang the carbon fiber formed product in an environment having the temperature capable of melting wax, so that the wax mold is molten and flows out from the flow-guiding hole of wax.

Description

Method for manufacturing carbon fiber hollow molded product and molding die thereof

The present invention relates to a method for producing a carbon fiber hollow molded article, and a mold used in the method.

Regarding the manufacturing method of the carbon fiber hollow molded product, the bicycle rim is taken as an example, and the description of the related art is given in the Republic of China invention patent I308527 (hereinafter referred to as the 527 case). In the case of 527, the air bag forming method is adopted, and the carbon fiber prepreg is stacked and formed into a rim initial embryo having an inflatable space, and the air bag is placed in the inflatable space, and the rim initial embryo having the air bag inside is placed in the case. In the mold, the air bag is inflated in three stages in the mold, and the inflatable bag of the air bag is inflated, forcing the outer surface of the rim initial embryo to completely fit closely to the inner mold surface of the mold to form a shape. The rim of the cavity is completely molded into the embryo; then, the rim is taken out from the mold to form an embryo, and then a procedure of hot baking and surface processing is performed to complete a carbon fiber rim.

The Republic of China invention patent I341247 (hereinafter referred to as 247 case), 247 case shows that the use of air bag forming method may face the problem of failure of the formation of carbon fiber products due to the collapse of the air bag, and the case of 247 also shows that the air bag is easily deformed by force. Will affect the wall thickness uniformity of carbon fiber products. Therefore, in the case of 247, it is proposed to preform a rigid solid heat shrinkable core mold in the air bag, and the heat shrinkable core mold supports the air bag to ensure that the carbon fiber tow is not entangled by the force when the carbon fiber tow is wound around the air bag. After the carbon fiber tow is wound, the dissolved heat shrinkable core mold is taken out, and the air bag wrapped with the carbon fiber tow is placed in the mold, and the air bag is inflated to expand, and the carbon fiber layer is pressed against the inner wall of the cavity. And forming a finished product.

The forming method proposed in Cases 527 and 247 can only form a simple surface shape such as a round tube. The article does not propose a manufacturing scheme for the carbon fiber hollow molded article which requires a reinforcing rib or a complicated surface shape inside.

The method proposed by the Republic of China invention patent I356023 (hereinafter referred to as the 023 case) can make the inner peripheral surface of the carbon fiber hollow molded article have reinforcing ribs. In the case of 023, a hollow thin-walled mandrel is made of a foamed material, and the surface of the mandrel has at least one forming groove, and the carbon fiber is wound around the outside of the mandrel, and an air bag is placed inside the mandrel, and then enters the mold. The air bag is inflated and heated and pressurized, so that the carbon fiber is formed according to the surface shape of the mandrel and the shape of the inner wall of the cavity; the carbon fiber molded product is taken out from the mold, and the inner air bag and the mandrel are taken out, that is, the carbon fiber hollow is completed. The molded article has an inner peripheral surface of the molded article having reinforcing ribs corresponding to the grooves.

The method proposed by the Republic of China invention patent I357872 (hereinafter referred to as the 872 case) can form a carbon fiber hollow molded product having a complicated surface shape. Case 872 is the body of the carbon fiber rim formed by the upper mold, the middle mold and the lower mold, and the tire groove and the inverted hook.

Each of the above documents mentions the technology for making carbon fiber hollow molded articles, and they all focus on how to shape the carbon fiber material into a predetermined shape. As for the structural solidity and uniformity of the carbon fiber product, the problems are not asked. However, it can be expected that the conventional molding die of the carbon fiber hollow molded product adopts the conventional type of the upper die and the lower die, and is matched with the inflating means inside the carbon fiber primary embryo to shape the initial embryo into a molded article. This is a means of internal and external pressurization that promotes the shaping of carbon fibers, but does not ensure the solidity and uniformity of the carbon fiber structure. For example, the internal and external pressurization means that the longitudinal space between the individual carbon fiber tows is compressed, but the lateral space is not, so that during the molding process, the carbon fiber tow may be laterally displaced due to the longitudinal thrust. This situation is not recognized by the naked eye, but it does affect the structural density, uniformity, and structural strength of the carbon fiber, and the shape variation rate of the carbon fiber molded article increases. Solve this problem The method is currently to increase the amount of winding or stacking of carbon fibers, and to increase the structural thickness of the carbon fibers. However, the problem is that the cost of the carbon fiber material increases and the weight of the finished product becomes heavier.

The purpose of the present invention is to provide a method for manufacturing a carbon fiber hollow molded article and a mold thereof, which can improve the structural compactness and uniformity of the carbon fiber product, thereby improving the structural toughness of the carbon fiber product.

The invention uses a wax mold as an inner mold of a carbon fiber primordial, and the carbon fiber tow is wound and tied to the outside of the wax mold to form a carbon fiber primordial, the wax mold provides comprehensive support for the interior of the carbon fiber primordial, avoiding carbon fiber primordial Collapse occurred.

The carbon fiber primordial and the internal wax mold are placed in a molding die, and the carbon fiber primordial is molded into a carbon fiber molded product according to the cavity shape of the mold through a heating and pressurizing step. During the molding process, the molding die provides upper, lower and lateral pressure to the carbon fiber primord, and cooperates with the internal support of the wax mold to compress the longitudinal and lateral spaces between the carbon fiber tows, thereby improving the structural rigidity of the carbon fiber. Property, uniformity, in this way to achieve the structural strength and toughness of the carbon fiber product, so the present invention does not need to increase the amount of carbon fiber tow, the amount of stacking and structural thickness, so it does not increase the cost of carbon fiber, nor increase The weight of the finished carbon fiber.

The outer shape of the wax mold can be set, and the shape of the cavity of the mold can be matched to produce a hollow structure with a reinforcing structure or a multi-chamber carbon fiber, and the reinforcing structure can be a reinforcing rib along the inner circumferential surface of the finished carbon fiber, or It is a reinforcing rib that spans the opposite inner wall. Further, the present invention can additionally attach a reinforcing member to a predetermined position of the carbon fiber hollow molded article.

After the carbon fiber is finished and demolded, a small hole can be drilled to melt and flow the internal wax mold by heating. The melted wax taken out can be recycled and reused to make a new wax mold, which reduces the cost of molding.

For the convenience of the description, the central idea expressed in the column of the above summary of the present invention is expressed by a specific embodiment. Various items in the embodiments are depicted in terms of ratios, dimensions, amounts of deformation, or displacements that are suitable for illustration, and are not drawn to the proportions of actual elements, as set forth above. In the following description, the description of the up, down, left, and right directions is defined in accordance with the orientation of our views, and is not intended to limit the present invention.

The method for manufacturing a carbon fiber hollow molded article of the present invention comprises: a wax molding step of prefabricating a wax mold according to internal and external forms of the carbon fiber molded article; and a carbon fiber initial embryo forming step of winding the carbon fiber tow or coating on the outside of the wax mold. a carbon fiber prepreg, forming a carbon fiber primordial; a molding step, placing the carbon fiber primordial with an internal wax mold in a molding die, the molding die comprising an upper die, a lower die and a side die; and a molding step The carbon fiber primordial is subjected to hot press forming using the molding die at a temperature of 120 ° C to 140 ° C and a pressure of 6 kg / cm 2 to 17 kg / cm 2 , and the carbon fiber primordial through the upper mold, the lower mold and the side mold Applying the above, lower, and lateral pressures to mold the carbon fiber primordial in the mold, and then removing the carbon fiber molded product from the mold; the wax mold removing step, drilling the wax guiding hole on the carbon fiber molded product, and then molding the carbon fiber molded product Hanging in an environment with a molten wax temperature causes the wax mold to melt out of the wax flow guiding hole. The wax mold removal step and the wax mold forming step may be combined, that is, the wax which is conducted out of the wax is dropped into one mold, and another new wax mold is produced while the wax mold is taken out.

The following description describes a wax mold, a carbon fiber primordial, a molding die, and a carbon fiber molded article in the production method of the present invention.

In the above wax molding step, the wax pattern 10 is made according to the internal and external types of the carbon fiber molded article, and the first drawing describes only one of the aspects, and is not intended to limit the present invention. The wax pattern 10 has a contour shape conforming to the shape of the carbon fiber molded article, and the surface thereof is provided with the molding groove 11 or the reinforcing object placement groove 12 in accordance with the inner shape of the carbon fiber molded article.

As shown in the second figure, when the carbon fiber tow or the carbon fiber prepreg is wound on the outside of the wax mold 10 to form the carbon fiber primordial 20, the basic shape of the carbon fiber primordial 20 is defined according to the outline of the wax pattern 10, according to which The reinforcing groove rib 21 is formed in the inside of the carbon fiber priming head 20 in the molding groove 11, and the reinforcing member 22 is preset in the reinforcing object placing groove 12. The wax mold 10 is used as an inner mold of the carbon fiber primordial 20 to provide comprehensive support for the interior of the carbon fiber primordial 20 to prevent collapse of the carbon fiber primordial.

The third figure depicts the use of a plurality of wax patterns 10 to form reinforcing rib beams 23 (or forming a multi-chamber configuration) across the sidewalls within the interior of the carbon fiber preform 20. The first wax pattern 101 is wound around the carbon fiber tow, and then the second wax pattern 102 is wound, so that the first wax pattern 101 and the second wax pattern 102 become the internal support of the carbon fiber priming unit 20.

The fourth figure depicts a molding die 30 of the present invention, which includes an upper die 31, a lower die 33, and a side die 35. The upper mold 31 and the lower mold 33 are upper and lower molds, each having a corresponding cavity 32, 34. The shape of the cavity 32, 34 is determined according to the appearance of the carbon fiber molded article, and the carbon fiber primordial 20 Placed in the cavities 32, 34. The side mold 35 is coupled to the side edges of the upper mold 31 and the lower mold 33, and the means for bonding may be screw-locked. An airtight gasket 37 is disposed between the side mold 35 and the upper mold 31 and the lower mold 33. The side mold 35 has a one side pressure introduction structure 38 for applying a side pressure to the carbon fiber primordial. The side pressure introduction structure 38 may be a pressure chamber 381 and a gas pressure film 382. The air line 383 communicates with the air pressure chamber 381, and the air pressure chamber 381 is injected with air. The air pressure causes the gas pressure film 382 to swell toward the carbon fiber primordial 20, thereby forming a side pressure on the carbon fiber primordial.

As shown in the fifth figure, the side pressure introduction structure 38 may be an air bag 384, and the air bag 384 is filled with air to be inflated, thereby forming a side pressure on the carbon fiber primordial.

The molding die 30 provides upper, lower and lateral pressure to the carbon fiber primordial 20, and cooperates with the internal support of the wax mold 10 to compress the longitudinal and lateral spaces between the carbon fiber tows of the carbon fiber primordial 20, thereby increasing the carbon fiber. The structural compactness and uniformity are used to improve the structural toughness of the finished carbon fiber product.

As a sixth drawing, the manner in which the carbon fiber molded article 40 after demolding is subjected to dewaxing will be described. A wax guide hole 41 is drilled in the carbon fiber molded product 40, and the carbon fiber molded product 40 is hung in an environment having a temperature of melting wax, and the wax mold is melted and discharged from the wax flow guiding hole 41. The carbon fiber molded article 40 having a plurality of wax patterns 10 is respectively drilled with wax guiding holes 41 in accordance with the position of the wax pattern 10 so as to be drawn out of each of the wax patterns 10. The drawn wax can be dropped into a mold 50, and another new wax mold is produced while the wax mold is taken out.

The dewaxed carbon fiber molded article 40 is described as the seventh and eighth figures, and the seventh drawing is formed by the wax mold 10 of the first drawing, which is a hollow molded article along the inner circumference of the carbon fiber molded article 40. The face has reinforcing ribs 42 and has an additional reinforcing member 43. The eighth figure is formed by the wax pattern 10 of the second figure, with a reinforcing rib 44 extending across the opposite inner wall or forming a multi-chamber configuration 45.

The present invention is described by taking a bicycle rim as an example. However, the implementation of the present invention is not limited thereto, and the carbon fiber hollow molded article can adopt the method and the mold of the present invention.

10‧‧‧ wax mold

101‧‧‧The first wax mold

102‧‧‧Second wax mold

11‧‧‧Molding trough

12‧‧‧Reinforcing object placement slot

20‧‧‧Carbon fiber embryo

21‧‧‧Reinforced ribs

22‧‧‧Reinforcing objects

23‧‧‧Reinforced rib beam

30‧‧‧Molding mould

31‧‧‧上模

32‧‧‧ cavity

33‧‧‧Down

34‧‧‧ cavity

35‧‧‧ side mode

37‧‧‧Airtight gasket

38‧‧‧ Side pressure introduction structure

381‧‧‧Pneumatic chamber

382‧‧‧Pneumatic membrane

383‧‧‧Air line

384‧‧‧Airbag

40‧‧‧Carbon fiber moldings

41‧‧‧Wax diversion

42‧‧‧Reinforced ribs

43‧‧‧Reinforcing objects

44‧‧‧Reinforced rib beam

45‧‧‧Multi-cavity structure

50‧‧‧ model

The first figure is a schematic cross-sectional view of a wax mold of the present invention.

The second figure is a schematic view of the present invention in which a carbon fiber tow or a carbon fiber prepreg is wrapped around a wax mold to form a carbon fiber primordial.

The third figure is a schematic diagram of several wax molds supported inside the carbon fiber primordial.

The fourth figure is a first embodiment of the molding die of the present invention.

The fifth figure is a second embodiment of the molding die of the present invention.

Fig. 6 is a view showing the manner in which the carbon fiber molded article of the present invention is dewaxed.

Figure 7 is a cross-sectional view showing an embodiment of a carbon fiber molded article of the present invention.

Figure 8 is a cross-sectional view showing the second embodiment of the carbon fiber molded article of the present invention.

10‧‧‧ wax mold

20‧‧‧Carbon fiber embryo

22‧‧‧Reinforcing objects

30‧‧‧Molding mould

31‧‧‧上模

32‧‧‧ cavity

33‧‧‧Down

34‧‧‧ cavity

35‧‧‧ side mode

37‧‧‧Airtight gasket

38‧‧‧ Side pressure introduction structure

381‧‧‧Pneumatic chamber

382‧‧‧Pneumatic membrane

383‧‧‧Air line

Claims (5)

A method for manufacturing a carbon fiber hollow molded article, comprising: a wax molding step of prefabricating a wax mold according to internal and external forms of a carbon fiber molded product; and a carbon fiber initial embryo forming step of winding carbon fiber tow or coating on the outside of the wax mold a carbon fiber prepreg, forming a carbon fiber primordial; a molding step, placing the carbon fiber primordial with an internal wax mold in a molding die, the molding die comprising an upper die, a lower die and a side die; and a molding step The carbon fiber primordial is subjected to hot press forming by using the molding die, and the upper, lower and lateral pressures of the carbon fiber primordial are applied through the upper mold, the lower mold and the side mold, so that the carbon fiber primordial embryo is shaped in the mold. Demolition of the carbon fiber molded product; wax mold removal step, drilling a wax guide hole on the carbon fiber molded product, and suspending the carbon fiber molded product in an environment having a temperature of melting wax to melt the wax mold from the wax guide The orifice flows out. The method for producing a carbon fiber hollow molded article according to claim 1, wherein the wax mold removing step further comprises injecting the outflowing wax into a mold to prepare a new wax mold. A molding die for a carbon fiber hollow molded product, comprising: an upper die and a lower die, wherein the upper die and the lower die are upper and lower combined molds each having a corresponding cavity, and a carbon fiber primordial having a wax mold inside And placed in the cavity; a side mold, the side mold is coupled to the side of the upper mold and the lower mold, the side mold has a side pressure introduction structure for applying a side pressure to the carbon fiber primordial. The molding die for a carbon fiber hollow molded article according to claim 3, wherein the side pressure introducing structure comprises a gas pressure chamber formed in the side mold, and a gas pressure film disposed in the gas pressure chamber, the air pressure The chamber injects air, and the air pressure causes the diaphragm to bulge and deform, thereby The carbon fiber primordial is formed on one side. The molding die for a carbon fiber hollow molded article according to claim 4, wherein the side pressure introducing structure comprises an air bag provided in the side mold, and the air bag is filled with air to bulge, thereby the carbon fiber The primordial formation is pressed on one side.