Fiber filament cutting device and method for 3D printing of continuous fiber reinforced composite materials

Abstract

A fiber filament cutting device and method for 3D printing of continuous fiber reinforced composite materials, comprising a print head bracket and a stepper motor module installed thereon, the print head bracket is connected to the printer; the stepper motor module provides power to a cutting unit, the cutting unit is located below the stepper motor module, the cutting unit is connected to a slider, the slider slides along a linear slide rail, and the linear slide rail is installed on the print head bracket through a fixing frame; a print head is provided below the cutting unit, and the print head is fixed on the print head bracket; when printing, the cutting unit is in a raised state; when cutting, the stepper motor pushes the cutting unit to move downward to reach the cutting position, the cylinder pushes the cutting slider to move downward, the arc-shaped cutter head closes, and the fiber filaments are cut; after cutting, the cylinder drives the cutting slider to move upward, the arc-shaped cutter head opens, and the stepper motor pulls the cutting unit to move upward to reset, completing the cutting process; the device of the present invention has a simple structure, high reliability, and low price.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing of composite materials, and in particular to a fiber filament cutting device and method for 3D printing of continuous fiber reinforced composite materials. Background Art

[0002] Composite materials have excellent performance. Their unique advantages such as high specific strength, high specific stiffness, high damage safety, good damping and shock absorption, good fatigue resistance, strong designability, corrosion resistance, and easy large-area integral forming have continuously expanded their application scope and have been widely used in high-tech fields such as aerospace.

[0003] At present, with the rapid development of 3D printing technology, 3D printing technology is applied to the field of composite materials, thus giving birth to continuous fiber reinforced composite material 3D printing technology, which not only reduces the manufacturing cost of composite materials, but also effectively improves its manufacturing efficiency. However, there are relatively few shearing devices developed specifically for composite material 3D printing technology. The existing shearing equipment usually cuts the fiber filaments in front of the print head, and then completes the next printing process through secondary re-feeding, which has the disadvantages of poor reliability, complex structure, and high price. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a fiber filament cutting device and method for 3D printing of continuous fiber reinforced composite materials. The device has a simple structure, high reliability, low price, and is applicable to common fiber reinforced composite materials.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A fiber filament cutting device for 3D printing of continuous fiber reinforced composite materials, comprising a print head bracket 1 and a stepper motor module 2 installed thereon, the print head bracket 1 is connected to the printer; the stepper motor module 2 provides power to a shearing unit 3, the shearing unit 3 is located below the stepper motor module 2, the shearing unit 3 is installed on a slider 4, the slider 4 slides on a linear slide rail 5, and the linear slide rail 5 is installed on the print head bracket 1 through a fixing frame 7; a print head 6 is provided below the shearing unit 3, and the print head 6 is fixed on the print head bracket 1.

[0007] There are two pairs of sliders 4 and linear guide rails 5 , which are respectively installed on the left and right sides of the shearing unit 3 .

[0008] The stepper motor module 2 includes a stepper motor 21, which is mounted on a motor mounting plate 22, which is connected to the print head bracket 1, and the motor shaft of the stepper motor 21 is cooperatively connected with a transmission nut 23, which is connected to a transmission bracket 24, and the transmission bracket 24 is connected to the shearing unit 3.

[0009] The motor shaft of the stepper motor 21 is a lead screw, and the driving nut 23 and the motor shaft transmit power through threads, converting the rotational motion of the motor shaft into the linear motion of the driving nut 23 .

[0010] The shearing unit 3 includes a cylinder 32, which is fixed on a shearing bracket 31, and the shearing bracket 31 is connected to a transmission bracket 24; the piston rod of the cylinder 32 has a threaded hole and is connected to a U-shaped bracket 33, and both ends of the U-shaped bracket 33 are connected to shearing sliders 35 on the left and right sides, and the shearing sliders 35 slide along shearing slide rails 34, and the shearing slide rails 34 are fixed to the shearing bracket 31; the shearing slider 35 is connected to the upper end of the connecting rod 36 through a fixed shaft 37, and the connecting rod 36 can rotate around the fixed shaft 37; the other end of the connecting rod 36 is connected to an arc-shaped cutter head 39 through another fixed shaft 37; the arc-shaped cutter head 39 is installed on a shell 38, and the shell 38 is fixed to the shearing bracket 31.

[0011] The fixed shaft 37 is installed with the arc-shaped cutter head 39 and the mounting holes on the shear slider 35 by interference fit, and is installed with the connecting rod 36 by clearance fit, so that the connecting rod 36 can rotate around the fixed shaft 37 .

[0012] The shell 38 is provided with a slideway inside, and the arc-shaped cutter head 39 slides left and right inside the shell 38. The shell 38 is made of wear-resistant material, and lubricating oil is added at the contact position.

[0013] The connecting rod 36 and the shearing slider 35 and the arc-shaped cutter head 39 connected thereto together form a set of double-slider structures, which convert the longitudinal movement from the cylinder 32 into lateral movement to realize the opening and closing of the arc-shaped cutter head 39.

[0014] The arc-shaped cutter head 39 is composed of a left arc-shaped cutter head 391 and a right arc-shaped cutter head 392. When shearing, the two cutter heads move toward each other to form a shearing force.

[0015] A method for using a fiber filament cutting device for 3D printing of a continuous fiber reinforced composite material comprises the following steps:

[0016] 1) Move the print head bracket 1 upward;

[0017] 2) starting the stepper motor 21 to drive the shearing unit 3 to move downward, and the fiber filaments drawn out of the print head 6 enter the middle of the arc-shaped cutter head 39;

[0018] 3) The solenoid valve controls the cylinder 32 to push the arc-shaped cutter head 39 to close and cut the fiber filaments;

[0019] 4) After the fiber is cut, the solenoid valve controls the cylinder 32 to open the arc-shaped cutter head 39;

[0020] 5) The stepping motor 21 drives the shearing unit 3 to move upward and reset, and the lowest point of the shearing unit 3 after reset is higher than the lowest point of the print head 6;

[0021] 6) Move the print head support 1 downward and start executing the remaining printing instructions.

[0022] The beneficial effects of the present invention are:

[0023] The present invention creatively proposes to use an arc-shaped cutter head 39 to cut pre-impregnated fiber filaments. During the cutting process, the print head bracket 1 is first moved upward; the stepper motor 21 is started to drive the cutting unit 3 to move downward, and the fiber filaments led out of the print head 6 enter the middle of the arc-shaped cutter head 39; the solenoid valve controls the cylinder 32 to close the arc-shaped cutter head 39 to cut the fiber filaments; since the cross-section of the fiber filaments is circular, the arc-shaped cutter head 39 is subjected to more uniform force than straight-blade scissors during shearing, which can better ensure that the cross-section of the fiber after cutting maintains its original shape and is not flattened.

[0024] The present invention uses a double slider mechanism to transmit shear force. Through the force analysis of the double slider mechanism, it can be known that when the thrust of the cylinder 32 is constant, the shear force of the scissors will gradually increase with the closing of the arc-shaped blade 39, so the double slider mechanism can generate a larger shear force, better solve the problem of incomplete shearing, and has a better shearing effect on common fibers.

[0025] The present invention has a simple structure and a more reasonable layout. It realizes lateral shearing by means of a longitudinal arrangement, thus saving space for the position of the print head 6. The lowest point of the shearing unit 3 after reset is higher than the lowest point of the print head 6. The shearing unit 3 will not interfere with the secondary printing, thus ensuring the technical effect of 3D printing continuity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the device of the present invention.

[0027] Figure 2 Schematic diagram of the stepper motor module of the device of the present invention.

[0028] Figure 3 Schematic diagram of the shear unit of the device of the present invention.

[0029] Figure 4 It is a schematic diagram of the installation of the housing of the device of the present invention and the arc-shaped cutter head.

[0030] Figure 5 yes Figure 4 AA cross-section diagram.

[0031] Figure 6 It is a schematic diagram of the shear bracket of the device of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings.

[0033] Reference Figure 1 A fiber filament cutting device for 3D printing of continuous fiber reinforced composite materials comprises a print head bracket 1 and a stepper motor module 2, a shearing unit 3, a slider 4, a linear slide 5, a print head 6 and a fixing bracket 7 installed thereon, wherein the print head bracket 1 is connected to the printer through bolts; the stepper motor module 2 provides power to the shearing unit 3, the shearing unit 3 is located below the stepper motor module 2, the shearing unit 3 is connected to the slider 4, the slider 4 can slide along the linear slide 5, the linear slide 5 is installed on the print head bracket 1 through the fixing bracket 7, there are two pairs of sliders 4 and linear slides 5, which are respectively installed on the left and right sides of the shearing unit 3; a print head 6 is arranged below the shearing unit 3, the print head 6 is fixed to the print head bracket 1 through bolts, a heating rod and a temperature measuring probe are installed inside the print head 6, and the print head 6 can be heated to a set temperature and keep the temperature constant.

[0034] Reference Figure 2 The stepper motor module 2 includes a stepper motor 21, a motor mounting plate 22, a transmission nut 23 and a transmission bracket 24. The stepper motor 21 is mounted on the motor mounting plate 22. The motor mounting plate 22 is fixed to the print head bracket 1 by bolts. The motor shaft of the stepper motor 21 and the transmission nut 23 are cooperatively connected. The transmission nut 23 is connected to the transmission bracket 24. The transmission bracket 24 is connected to the shearing unit 3.

[0035] The motor shaft of the stepper motor 21 is a lead screw, and the transmission nut 23 and the motor shaft transmit power through threads, converting the rotational motion of the motor shaft into the linear motion of the transmission nut 23. The transmission nut 23 transmits the motion to the shearing unit 3 through the transmission bracket 24, thereby enabling the shearing unit 3 to achieve lifting and lowering actions.

[0036] Reference Figure 3 , Figure 4 , Figure 5 and Figure 6The shearing unit 3 comprises a shearing bracket 31, a cylinder 32, a U-shaped bracket 33, a shearing slide rail 34, a shearing slider 35, a connecting rod 36, a fixed shaft 37, a housing 38 and an arc-shaped cutter head 39; the cylinder 32 is fixed on the shearing bracket 31, and the shearing bracket 31 and the transmission bracket 24 are connected by bolts; the piston rod of the cylinder 32 has a threaded hole and is connected to the U-shaped bracket 33 by bolts, and the two ends of the U-shaped bracket 33 are connected to the shearing sliders 35 on the left and right sides by bolts, so as to transmit the telescopic movement of the cylinder 32 to the shearing slider 35; the shearing slider 3 5 slides along the shearing slide rail 34, which is fixed on the shearing bracket 31; the shearing slider 35 is connected to the upper end of the connecting rod 36 through a fixed shaft 37, and the connecting rod 36 can rotate around the fixed shaft 37; the other end of the connecting rod 36 is connected to the arc cutter head 39 through another fixed shaft 37; the arc cutter head 39 is installed on the housing 38, and the housing 38 is fixed to the shearing bracket 31 by bolts to play a supporting role; the two sides of the shearing bracket 31 are connected to the print head bracket 1 through the sliders 4 and the linear slide rails 5, and can slide up and down under the drive of the stepper motor 21.

[0037] The fixed shaft 37 is installed with an interference fit with the arc-shaped cutter head 39 and the mounting holes on the shear slider 35 , and is installed with a clearance fit with the connecting rod 36 , so that the connecting rod 36 can rotate around the fixed shaft 37 .

[0038] The shell 38 is designed with a slideway inside, and the arc-shaped cutter head 39 slides left and right inside the shell 38. The shell 38 is made of wear-resistant material, and a proper amount of lubricating oil should be added at the contact position to reduce the friction resistance generated during relative sliding.

[0039] The connecting rod 36 and the shearing slider 35 and the arc-shaped cutter head 39 connected thereto together form a set of double-slider structures, which convert the longitudinal movement from the cylinder 32 into lateral movement to realize the opening and closing of the arc-shaped cutter head 39.

[0040] Reference Figure 5 The arc-shaped cutter head 39 is composed of a left arc-shaped cutter head 391 and a right arc-shaped cutter head 392. When shearing, the two cutter heads move toward each other to form a shearing force.

[0041] During printing, the shearing unit 3 is in a raised state; during shearing, the stepper motor 21 pushes the shearing unit 3 to move downward to the shearing position, the cylinder 32 pushes the shearing slider 35 to move downward, and the longitudinal displacement is converted into lateral displacement through the connecting rod 36, the arc-shaped cutter head 39 closes, and the fiber filaments are cut; after shearing, the cylinder 32 pulls the shearing slider 35 to move upward, the arc-shaped cutter head 39 opens, and the stepper motor 21 pulls the shearing unit 3 upward. After resetting, the lowest point of the shearing unit 3 is higher than the lowest point of the print head 6, and the shearing process is completed.

[0042] A method for using a fiber filament cutting device for 3D printing of a continuous fiber reinforced composite material comprises the following steps:

[0043] 1) Move the print head bracket 1 upward;

[0044] 2) starting the stepper motor 21 to drive the shearing unit 3 to move downward, and the fiber filaments drawn out of the print head 6 enter the middle of the arc-shaped cutter head 39;

[0045] 3) The solenoid valve controls the cylinder 32 to push the arc-shaped cutter head 39 to close and cut the fiber filaments;

[0046] 4) After the fiber is cut, the solenoid valve controls the cylinder 32 to open the arc-shaped cutter head 39;

[0047] 5) The stepping motor 21 drives the shearing unit 3 to move upward and reset, and the lowest point of the shearing unit 3 after reset is higher than the lowest point of the print head 6;

[0048] 6) Move the print head support 1 downward and start executing the remaining printing instructions.

[0049] 3D printing of glass fiber reinforced resin-based composite materials. When it reaches the shearing point, the print head bracket 1 rises 5mm, the shearing unit 3 drops 7mm, and the shearing is performed at air pressures of 3, 4, 5, and 6kgf / cm² respectively. It is found that when the pressure of cylinder 32 is 3kgf / cm², the fiber filaments are not cut off at all; when the pressure of cylinder 32 is 4 or 5kgf / cm², only part of the fiber filaments are cut off, and there are more burrs at the incision; when the pressure of cylinder 32 is 6kgf / cm², the fiber filaments are completely cut off, and the fracture is relatively smooth. Therefore, when the cylinder pressure is 6kgf / cm², the shearing effect of glass fiber reinforced resin-based composite materials is best.

Claims

1. A fiber filament cutting device for 3D printing of continuous fiber reinforced composite materials, comprising a print head support (1) and a stepper motor module (2) mounted thereon, the print head support (1) being connected to a printer; characterized in that: The stepper motor module (2) provides power to the shearing unit (3). The shearing unit (3) is located below the stepper motor module (2). The shearing unit (3) is mounted on a slider (4). The slider (4) slides on a linear slide rail (5). The linear slide rail (5) is mounted on a print head bracket (1) via a fixing frame (7). A print head (6) is provided below the shearing unit (3). The print head (6) is fixed on the print head bracket (1). The stepper motor module (2) comprises a stepper motor (21), the stepper motor (21) is mounted on a motor mounting plate (22), the motor mounting plate (22) is connected to a print head bracket (1), a motor shaft of the stepper motor (21) and a transmission nut (23) are cooperatively connected, the transmission nut (23) is connected to a transmission bracket (24), and the transmission bracket (24) is connected to a shearing unit (3); The shearing unit (3) comprises a cylinder (32), the cylinder (32) being fixed on a shearing bracket (31), the shearing bracket (31) being connected to a transmission bracket (24); a piston rod of the cylinder (32) having a threaded hole connected to a U-shaped bracket (33), the two ends of the U-shaped bracket (33) being connected to shearing sliders (35) on the left and right sides; the shearing sliders (35) slide along shearing slide rails (34), the shearing slide rails (34) being fixed on the shearing bracket (31); the shearing sliders (35) being connected to the upper ends of the connecting rods (36) via a fixed shaft (37), the connecting rods (36) being able to rotate around the fixed shaft (37); the other end of the connecting rods (36) being connected to an arc-shaped cutter head (39) via another fixed shaft (37); the arc-shaped cutter head (39) being mounted on a housing (38), the housing (38) being fixed on the shearing bracket (31); The connecting rod (36) and the shearing slider (35) and the arc-shaped cutter head (39) connected thereto together form a double-slider structure, which converts the longitudinal movement from the cylinder (32) into lateral movement, thereby realizing the opening and closing of the arc-shaped cutter head (39); There are two pairs of sliders (4) and linear guide rails (5), which are respectively installed on the left and right sides of the shearing unit (3).

2. The fiber filament cutting device for 3D printing of continuous fiber reinforced composite materials according to claim 1, characterized in that: The motor shaft of the stepper motor (21) is a lead screw, and power is transmitted between the transmission nut (23) and the motor shaft via a thread, thereby converting the rotational motion of the motor shaft into the linear motion of the transmission nut (23).

3. The fiber filament cutting device for 3D printing of continuous fiber reinforced composite materials according to claim 1, characterized in that: The fixed shaft (37) is installed with an interference fit on the arc-shaped cutter head (39) and the mounting holes on the shear slider (35), and is installed with a clearance fit with the connecting rod (36), so that the connecting rod (36) can rotate around the fixed shaft (37).

4. The fiber filament cutting device for 3D printing of continuous fiber reinforced composite materials according to claim 1, characterized in that: A slideway is provided inside the shell (38), and the arc-shaped cutter head (39) slides left and right inside the shell (38). The shell (38) is made of wear-resistant material, and lubricating oil is added at the contact position.

5. The fiber filament cutting device for 3D printing of continuous fiber reinforced composite materials according to claim 1, characterized in that: The arc-shaped blade head (39) is composed of a left arc-shaped blade head (391) and a right arc-shaped blade head (392). When shearing is performed, the two blade heads move towards each other to generate a shearing force.

6. A method for using a fiber filament cutting device for 3D printing of a continuous fiber reinforced composite material according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) Move the print head bracket (1) upwards; 2) starting the stepper motor (21) to drive the shearing unit (3) to move downward, and the fiber filaments drawn out of the print head (6) enter the middle of the arc-shaped cutter head (39); 3) The solenoid valve controls the cylinder (32) to push the arc-shaped cutter head (39) to close and cut the fiber filaments; 4) After the fiber is cut, the solenoid valve controls the cylinder (32) to open the arc-shaped cutter head (39); 5) The stepping motor (21) drives the shearing unit (3) to move upward and reset, and the lowest point of the shearing unit (3) after reset is higher than the lowest point of the print head (6); 6) Move the print head support (1) downward and start executing the remaining printing instructions.

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