Carbon fiber tow pultrusion apparatus and method

Abstract

The application discloses a kind of carbon fiber tow pultrusion forming devices, including impregnation unit and forming unit, the impregnation unit includes impregnation groove, the impregnation roller for pressing tow is arranged in the impregnation groove, and the impregnation groove is located at the end slot of tow traction direction The edge of both sides is provided with the glue scraping roller for scraping the excess adhesion resin on tow;The forming unit includes positioning block, the drawing die of setting on positioning block and the positioning rod for the axial positioning of the drawing die;The upper edge height of the glue scraping roller is same with the center height of the drawing die;The drawing die has two kinds of state of opening and closing;The application further discloses a kind of carbon fiber tow pultrusion forming method.The device of the application has the characteristics of low cost, fast clamping, fast installation, simple operation, wherein the rotatable drawing die is more convenient to solve the problem of easy blockage and difficult cleaning of ordinary drawing die.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon fiber tow forming, in particular to a carbon fiber tow pultrusion forming device and method. BACKGROUND

[0002] Carbon fiber reinforced composite material is a composite material formed by taking carbon fiber or carbon fiber fabric as reinforcing body and taking resin, ceramic, metal, cement, carbon or rubber as matrix. Carbon fiber composite material is widely used in the fields of aerospace, rocket ship, automobile manufacturing, etc., and has the characteristics of small specific gravity, large specific strength, specific stiffness and specific modulus, excellent shock absorption, strong designability, good fatigue fracture resistance, corrosion resistance, good dimensional stability and easy large-area integral forming.

[0003] Carbon fiber tow is a no-twist long fiber bundle bundled with long filaments in a specified number, and is the most basic material in the carbon fiber product group. Carbon fiber tow forming methods include winding forming, pultrusion forming and mold pressing forming, etc. For example, the patent specification with publication number CN114715723A discloses a yarn collecting device for carbon fiber winding forming, which comprises: a yarn guide wheel set for guiding the tow; a wire arranging device provided with a rabbit head, the tow is wound on the wire arranging device after passing through the yarn guide wheel set; a chute, the length extension direction of the chute is vertical, and the wire arranging device is slidingly arranged in the chute; a driving mechanism; a spindle and a paper tube sleeved on the spindle, wherein the driving mechanism drives the spindle and the paper tube sleeved on the spindle to rotate continuously around their own axes; a driving device connected with the rabbit head, the rabbit head reciprocates along the axis of the spindle under the drive of the driving device; a back pressure roller fixed on the wire arranging device, the back pressure roller is in contact with the outer surface of the yarn roll; and a tension sensor arranged on the yarn guide wheel set.

[0004] Or the patent specification with publication number CN112793190A discloses a carbon fiber tow pre-impregnated material manufacturing device for fuel cell hydrogen energy automobile, which comprises a unwinding roller, an impregnation roller, a mold, a winding roller and a tank, the tank is provided with a fiber inlet and a fiber outlet, the unwinding roller is arranged directly above the fiber inlet, the impregnation roller is arranged in the tank, the mold is fixed at the fiber outlet, the winding roller is arranged beside the tank, the tank is filled with pre-impregnated liquid, and a heating device is further arranged in the tank, the heating device is used for heating the pre-impregnated liquid, the unwinding roller is wound with carbon fiber tow, the end of the carbon fiber tow passes through the fiber inlet and the fiber outlet, and is fixed on the winding roller, the impregnation roller presses the middle part of the fiber tow into the pre-impregnated liquid.

[0005] Among them, pultrusion is a process for producing polymer matrix composites in the form of continuous long products with constant cross section, which is a fast and economical material impregnation and curing method, and the resin content after molding can be accurately controlled. Pultrusion usually has processes such as impregnation, molding, curing, etc. At present, the carbon fiber tow pultrusion molding exists the problems of easy blockage of the molding die, high cost of the whole device, large floor area, complex disassembly and assembly, and difficult cleaning. SUMMARY

[0006] An object of the present application is to provide a carbon fiber tow pultrusion molding device which has the characteristics of low cost, fast clamping, fast installation and simple operation.

[0007] A carbon fiber tow pultrusion molding device, comprising a dipping unit and a molding unit, the dipping unit comprising a dipping tank, a dipping roller for pressing down the tow is arranged in the dipping tank, and a scraping roller for scraping off the excess adhesive resin on the tow is arranged on the edge of the tank opening at the end of the tow pulling direction; the molding unit comprises a positioning block, a wire drawing die arranged on the positioning block, and a positioning rod for axial positioning of the wire drawing die; the upper edge height of the scraping roller is the same as the center height of the wire drawing die;

[0008] The wire drawing die comprises a male die, an inner end cover, an inner rotating body and a female die arranged in sequence, and the male die, the inner end cover, the inner rotating body and the female die are all provided with a center hole and a gap extending to the center hole; the male die and the inner rotating body are fixedly connected, the female die and the inner end cover are fixedly connected, and the male die and the inner rotating body can rotate relative to the female die and the inner end cover; after the male die or the female die rotates, the center holes of the male die and the female die can form a cylindrical hole at the center of the contact surface.

[0009] The rotatable wire drawing die has two states of opening and closing, which is convenient for the feeding and taking out of the carbon fiber tow and the molding, realizes the fast clamping of the device to the carbon fiber tow, and also solves the problems of easy blockage and difficult cleaning of the ordinary die.

[0010] As a preferred, the sidewall of the center hole of the outer entity of the male die and the female die is a spherical curved surface.

[0011] In the present scheme, the spherical curved surface hole with smooth surface can store more excess adhesive resin scraped off than the conical hole of the same size, thereby reducing the weight, and avoiding the scratching of the flat processing surface with the carbon fiber tow, which can cause internal filament breakage of the carbon fiber tow and affect the performance of the product after curing.

[0012] As a preferred, a V-shaped groove is arranged in the middle of the positioning block, the wire drawing die is in the form of a disc and stands in the V-shaped groove, and the positioning rod is provided with a pair of positioning rods respectively located on both sides of the wire drawing die, and the two ends of the positioning rod are adjustably fixed on the positioning block.

[0013] In the scheme, the V-shaped groove limits the drawing die in the radial direction, and the pair of positioning rods limits the drawing die in the axial direction, thereby ensuring the stability of the drawing die.

[0014] Preferably, the convex die is provided with a boss on the side in contact with the inner end cap, the boss is arranged in the central hole of the inner end cap and in contact with the edge of the central hole of the inner end cap; and the concave die is provided with an annular groove on the side in contact with the inner rotating body, and the inner rotating body is arranged in the annular groove.

[0015] Preferably, the contact pad is arranged on the edge of the first slot opening of the impregnation tank in the direction of the tow traction and can be in contact with the tow.

[0016] Further preferably, the material of the contact pad is soft rubber added with graphite or ceramic.

[0017] In the scheme, other smooth materials can also be added to the soft rubber to protect the carbon fiber tow.

[0018] Preferably, 2-4 impregnation rollers are arranged in the impregnation tank.

[0019] Preferably, 3-5 glue scraping rollers are arranged on the edges of the slot openings at the ends of the impregnation tank in the direction of the tow traction, and the upper edge of the last glue scraping roller has the same height as the center height of the drawing die.

[0020] Another object of the present application is to provide a carbon fiber tow pultrusion forming method using the carbon fiber tow pultrusion forming device.

[0021] a) Assembly: the device is assembled to ensure that the upper edge of the last glue scraping roller has the same height as the center height of the drawing die;

[0022] b) Loading: first, rotate the convex die or concave die of the drawing die to the open state, flatten the carbon fiber tow, and vertically send it from the gap to the center, rotate the convex die or concave die of the drawing die to the closed state, and position the drawing die by the positioning rods; then flatten the carbon fiber tow and place it under the impregnation rollers and stagger through the impregnation rollers; finally, flatten and straighten the carbon fiber tow to the natural state;

[0023] c) Resin addition: heat the resin at room temperature to a fluid state and add a curing agent, stir uniformly, and then add to the impregnation tank so that the resin covers the impregnation rollers;

[0024] d) Forming: pull the carbon fiber tow end of the right side of the drawing die until the required length of the carbon fiber tow is prepared;

[0025] e) Curing: cure the formed carbon fiber tow.

[0026] As preferred, in step a), the relative height of the upper edge of the last gluing roller to the center of the drawing die is judged by a laser pen or visual inspection.

[0027] Advantages of the present application:

[0028] (1) The rotatable drawing die provided by the present application has two states of opening and closing, which facilitates the feeding and taking out of the carbon fiber tows and the molding, realizes the quick clamping of the device to the carbon fiber tows, and also solves the problems of easy blocking and difficult cleaning of the drawing die.

[0029] (2) The device can be used in a laboratory environment, has simple structure, low manufacturing cost and simple operation, and can relatively simply realize the process flow of the pultrusion molding of the carbon fiber tows. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a structural schematic view of the device of the present application;

[0031] Figure 2 is a structural schematic view of the support frame;

[0032] Figure 3 is a structural schematic view of the drawing die in the open state;

[0033] Figure 4 is an exploded structural schematic view of the drawing die in the open state;

[0034] Figure 5 is another perspective exploded structural schematic view of the drawing die in the open state;

[0035] Figure 6 is a structural schematic view of the drawing die in the closed state.

[0036] Wherein: 100, carbon fiber tows, 1, impregnation tank, 2, impregnation roller, 3, gluing roller, 4, L-shaped upper positioning member, 5, L-shaped lower positioning member, 6, communication rod, 7, impregnation roller shaft, 8, T-shaped positioning member, 81, vertical part, 82, horizontal part, 9, contact pad, 10, slope, 11, connecting member, 12, positioning block, 121, T-shaped groove, 13, drawing die, 131, male die, 132, inner end cover, 133, inner rotating body, 134, female die, 135, positioning pin, 136, screw I, 137, screw II, 14, positioning rod, 141, T-shaped bolt. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] like Figure 1 As shown, a carbon fiber tow pultrusion molding device includes a dipping unit and a molding unit. The dipping unit includes a dipping tank 1, in which two dipping rollers 2 are arranged at intervals along the pulling direction of the carbon fiber tow 100; the dipping tank 1 is located along the pulling direction of the carbon fiber tow 100, and three scraping rollers 3 are arranged at intervals on both sides of the edge; wherein, the dipping roller 2 is used to press down the carbon fiber tow 100 to ensure that the carbon fiber tow 100 is completely dipped in glue, and the scraping roller 3 is used to scrape off excess adhesive resin on the pressed carbon fiber tow 100; during specific operation, the carbon fiber tow 100 passes through the dipping roller 2 in an interlaced manner.

[0039] The dipping roller 2 is fixed on the side wall of the notch of the dipping tank 1 through a support frame. Figure 2 As shown, the support frame includes an L-shaped upper positioning member 4 and an L-shaped lower positioning member 5, wherein the short side of the L-shaped upper positioning member 4 is fixed to the outer wall of the notch of the dipping tank 1 by screws, and the long side of the L-shaped upper positioning member 4 is located on the notch of the dipping tank 1; the short side of the L-shaped lower positioning member 5 is connected to the long side of the L-shaped upper positioning member 4 through a connecting rod 6, and both ends of the connecting rod 6 are tapped with internal threads, and the two ends are matched with nuts to realize the fixation of the L-shaped lower positioning member 5 and the L-shaped upper positioning member 4; the long side of the L-shaped lower positioning member 5 is located on the inner side of the dipping tank 1; one end of the dipping roller shaft 7 is tapped with an internal thread, and is fixed to the L-shaped lower positioning member 5 by a nut, and the dipping roller 2 is interference fit on the dipping roller shaft 7.

[0040] The scraper roller 3 is specifically fixed to the side wall of the notch at the end of the dipping tank 1 via a T-shaped positioning piece 8. The T-shaped positioning piece 8 is placed vertically, with the vertical portion 81 closely attached to the outer wall of the notch of the dipping tank 1 and fixed to the outer wall of the notch of the dipping tank 1 via screws located at the lower section of the vertical portion 81. The horizontal portion 82 is closely attached to the upper edge of the notch of the dipping tank 1. The upper section of the vertical portion 81 is connected to the dipping roller shaft 7 extending above the notch of the dipping tank 1 via a nut. The scraper roller 3 is also interference fit on the dipping roller shaft 7. In this embodiment, the T-shaped positioning pieces 8 are staggered on both sides of the upper edge of the notch of the dipping tank 1.

[0041] In the embodiment, the contact pad 9 is arranged on the edge of the first slot opening of the impregnation tank 1 along the pulling direction of the carbon fiber tows 100, which can contact the carbon fiber tows 100. The contact pad is made of soft rubber with smooth material such as graphite or ceramic, which can protect the carbon fiber tows 100. In addition, the impregnation tank 1 is provided with a slope 10 extending to the edge of the contact pad 9, which is used to guide the carbon fiber tows 100.

[0042] The forming unit comprises a positioning block 12, a wire drawing die 13 arranged on the positioning block 12, and a pair of positioning rods 14. The positioning block 12 is provided with a V-shaped groove in the middle, and the wire drawing die 13 is a disc and stands in the V-shaped groove, thereby playing a role of radial limiting. The pair of positioning rods 14 are located on both sides of the wire drawing die 13, and the two ends of the positioning rods 14 are adjustably fixed on the positioning block 12 and tightly contact the wire drawing die 13, thereby playing a role of axial limiting. Specifically, the positioning block 12 is provided with a T-shaped groove 121 on both sides of the V-shaped groove, and the two ends of the positioning rods 14 are adjustably fixed in the T-shaped grooves 121 through T-shaped bolts 141.

[0043] In the embodiment, the forming unit is located at the end of the impregnation tank 1, and the positioning block 12 and the impregnation tank 1 are positioned and connected through the connecting piece 11. Specifically, the two ends of the connecting piece 11 are threaded, and the side walls of the positioning block 12 and the impregnation tank 1 are provided with threaded holes. The two ends of the connecting piece are screwed into the corresponding threaded holes, thereby realizing the quick positioning of the impregnation unit and the forming unit. In addition, the height of the upper edge of the glue scraping roller 3 should be the same as the height of the center of the wire drawing die 13 during positioning and installation.

[0044] As shown in Figures 3-6 The wire drawing die 13 comprises a male die 131, an inner end cover 132, an inner rotating body 133 and a female die 134 arranged in sequence. The male die 131, the inner end cover 132, the inner rotating body 133 and the female die 134 are all provided with a central hole and an opening extending to the central hole. The male die 131 and the inner rotating body 133 are fixed through the screw I 136 passing through the central hole of the inner end cover 132, and the female die 134 and the inner end cover 132 are fixed through the screw II 137. In the embodiment, the contact surface of the male die 131 and the inner end cover 132 is provided with a boss, which is arranged in the central hole of the inner end cover 132 and contacts the edge of the central hole of the inner end cover 132. The contact surface of the female die 134 and the inner rotating body 133 is provided with an annular groove, and the inner rotating body 133 is arranged in the annular groove.

[0045] The center hole side wall of the outer side entity of the male die 131 and the female die 134 is a spherical curved surface, and is a thin cylindrical hole at the contact surface, so that the center hole of the male die 131 and the female die 134 can form a cylindrical hole with a certain thickness at the contact surface. Specifically, the drawing die 13 has two states of opening and closing, that is, the male die 131 and the inner rotating body 133 can rotate relative to the female die 134 and the inner end cover 132. In the open state, the openings of the male die 131, the inner end cover 132, the inner rotating body 133 and the female die 134 are directed to one side, which is convenient for the feeding and taking out of the carbon fiber tows 100. The male die 131 and the inner rotating body 133 are rotated to make the openings on the male die 131 and the inner rotating body 133 be out of position with the openings on the female die 134 and the inner end cover 132, so as to adjust to the closed state. In the closed state, the cylindrical hole formed by the center hole of the male die 131 and the female die 134 at the contact surface can be used to shape the carbon fiber tows 100. In the open or closed state, the male die 131, the inner end cover 132, the inner rotating body 133 and the female die 134 are positioned by a pair of positioning pins 135.

[0046] A carbon fiber tow pultrusion molding method using the above device, the carbon fiber tow pultrusion molding method comprising the following steps:

[0047] a) Assembly: Assemble the device to ensure that the upper edge height of the last end glue roller 3 is the same as the center height of the drawing die 13;

[0048] The relative height of the upper edge of the last end glue roller 3 and the center of the drawing die 13 is determined by a laser pen or visual observation;

[0049] b) Loading: First, pull out the positioning pin 135, rotate the male die 131 or the female die 134 of the drawing die 13 to the open state, the carbon fiber tows 100 are flattened and vertically fed from the opening to the center, and the male die 131 or the female die 134 of the drawing die 13 is rotated to the closed state, and the diagonal line is inserted into the two positioning pins 135 for positioning; move a pair of positioning rods 14 to position the drawing die 13; then place the carbon fiber tows 100 flat under the impregnation roller 2 and stagger through the impregnation roller 2; finally, the carbon fiber tows 100 are flattened and straightened to the natural state;

[0050] c) Add resin: Heat the resin at room temperature to a fluid state and add a curing agent, stir uniformly and add to the impregnation tank, so that the resin covers the impregnation roller;

[0051] Specifically, the resin uses epoxy resin E51, the curing agent uses triethylene tetramine, the epoxy resin E51 is viscous at room temperature, is heated to a fluid state by being placed in an oven with the temperature adjusted to 60°C, and then the curing agent triethylene tetramine is added and stirred uniformly and added to the impregnation tank 1. The mass ratio of the epoxy resin E51 to the curing agent triethylene tetramine is 8:1, and the resin covers the impregnation roller 2 to ensure that the carbon fiber tows 100 are completely impregnated.

[0052] d) forming: pulling the right end of the carbon fiber tow 100 in the drawing die 13 until the desired length of the carbon fiber tow 100 is prepared;

[0053] e) cutting: cutting the end and only keeping the carbon fiber tow 100 after forming;

[0054] f) curing: placing the carbon fiber tow 100 after forming in the oven to adjust the temperature to 60°C for 40 minutes for curing;

[0055] g) cleaning: cleaning the impregnation tank 1, the impregnation roller 2, the scraping roller 3, and the drawing die 13, and disassembling the device.

[0056] As another optional embodiment, the resin formula is epoxy resin E51 and medium-temperature curing agent with a mass ratio of 1:0.84, and during curing, the oven temperature is 120°C for one hour, and then the temperature is adjusted to 140°C for one hour for further curing.

[0057] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions recorded in the foregoing embodiments or make equivalent replacements to some of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A carbon fiber tow pultrusion apparatus, characterized by, The device comprises a dipping unit and a forming unit, the dipping unit comprises a dipping tank, a dipping roller is arranged in the dipping tank for pressing the tow, and a scraping roller is arranged on the edge of the tank opening at the end of the tow traction direction for scraping the excess resin adhered to the tow; the forming unit comprises a positioning block, a wire drawing die arranged on the positioning block, and a positioning rod for axial positioning of the wire drawing die; the upper edge height of the scraping roller is the same as the center height of the wire drawing die; The wire drawing die comprises a male die, an inner end cover, an inner rotating body and a female die arranged in sequence, the male die, the inner end cover, the inner rotating body and the female die are all provided with a center hole and a gap extending to the center hole; the male die and the inner rotating body are fixedly connected, the female die and the inner end cover are fixedly connected, and the male die and the inner rotating body can rotate relative to the female die and the inner end cover; after the male die or the female die rotates, the center holes of the male die and the female die can form a cylindrical hole at the center of the contact surface; The contact surface of the male die and the inner end cover is provided with a boss, the boss is arranged in the center hole of the inner end cover and is in contact with the edge of the center hole of the inner end cover; the contact surface of the female die and the inner rotating body is provided with an annular groove, and the inner rotating body is arranged in the annular groove.

2. The carbon fiber tow pultrusion apparatus of claim 1, wherein, The sidewall of the center hole of the outer entity of the male die and the female die is a spherical curved surface.

3. The carbon fiber tow pultrusion apparatus of claim 1, wherein, A V-shaped groove is arranged in the middle of the positioning block, the wire drawing die is in the form of a disc and stands in the V-shaped groove, and the positioning rod is arranged in pairs and is arranged on both sides of the wire drawing die, and the two ends of the positioning rod are adjustably fixed on the positioning block.

4. The carbon fiber tow pultrusion apparatus of claim 1, wherein, A contact pad is arranged on the edge of the tank opening at the beginning of the tow traction direction and can be in contact with the tow.

5. The carbon fiber tow pultrusion apparatus of claim 4, wherein, The material of the contact pad is soft rubber added with graphite or ceramic.

6. The carbon fiber tow pultrusion device according to claim 1, characterized in that: Two to four dipping rollers are arranged in the dipping tank at intervals.

7. The carbon fiber tow pultrusion apparatus of claim 1, wherein, Three to five scraping rollers are arranged on the edges of the tank opening at the end of the tow traction direction, and the upper edge height of the last scraping roller is the same as the center height of the wire drawing die.

8. A carbon fiber towpreg pultrusion process characterized by, The carbon fiber tow pultrusion forming device comprises the device according to any one of claims 1 to 7, and the carbon fiber tow pultrusion forming method comprises the following steps: a) assembly: the device is assembled to ensure that the upper edge height of the last scraping roller is the same as the center height of the wire drawing die; b) loading: first, rotate the male die or the female die of the wire drawing die to the open state, flatten the carbon fiber tow, and send it vertically from the gap to the center, then rotate the male die or the female die of the wire drawing die to the closed state, position the wire drawing die through the positioning rod, then place the carbon fiber tow under the dipping roller and stagger through the dipping roller, and finally flatten and straighten the carbon fiber tow to the natural state; c) resin adding: heat the resin at room temperature to a fluid state, add a curing agent, stir uniformly, and then add it to the dipping tank so that the resin covers the dipping roller; d) forming: pull the carbon fiber tow end at the right side of the wire drawing die until the required length of the carbon fiber dipped tow is prepared; e) curing: cure the carbon fiber dipped tow after forming.

9. The carbon fiber tow pultrusion method according to claim 8, characterized by, In step a), the relative height of the upper edge of the last scraping roller and the center of the wire drawing die is determined by a laser pen or visual observation.

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