CN115447141A - Recycling method for continuous fiber reinforced thermoplastic 3D printing composites - Google Patents

Abstract

The invention discloses a recovery method of a continuous fiber reinforced thermoplastic 3D printing composite material, which is characterized in that the composite material to be recovered is fixed at the bottom of a horizontal support plate, and a material receiving groove is arranged below the composite material; the heating head is moved to the lower surface contacting with the composite material, the mechanical arm is used for driving the heating head to move along the reverse direction of the 3D printing of the composite material, the resin matrix is melted by the heating head, the fiber in the melting area of the resin matrix is peeled off by the traction mechanism, and the melted resin matrix falls downwards into the material receiving groove. The method realizes the recovery of part of the resin matrix, improves the recovery benefit of the waste continuous fiber reinforced thermoplastic 3D printing composite material, also improves the recovery efficiency, and improves the economic benefit.

Description

Recycling method for continuous fiber reinforced thermoplastic 3D printing composites

technical field

The invention belongs to the technical field of recycling fiber composite materials, in particular to a method for recycling continuous fiber reinforced thermoplastic 3D printing composite materials.

Background technique

Continuous fiber-reinforced thermoplastic composites are based on thermoplastic resins, which have high damage tolerance, excellent mechanical properties, thermal properties and corrosion resistance, and have become a research hotspot for composite materials. High-end fields such as transportation, military industry, entertainment and leisure. The traditional preparation method of continuous fiber reinforced thermoplastic composites is mainly lamination-hot pressing technology. The emergence of 3D printing technology provides a process for the molding and processing of continuous fiber reinforced thermoplastic composites that can achieve a high degree of automation of composite products. The 3D printing technology of continuous fiber reinforced thermoplastic composites not only has the characteristics of forming complex composite products and high efficiency, but also can realize customized mechanical properties. Therefore, 3D printing technology has also received extensive attention and research. However, with the continuous fiber reinforced thermoplastic composite material 3D printing technology and the development of the composite material industry, a large amount of composite material waste is produced every year. The discarded composite material products not only pose a serious threat to the natural environment, but also a large number of Fibers, especially expensive carbon fibers and some high-performance thermoplastic special engineering plastics are difficult to recycle, which makes the development of composite materials encounter a bottleneck.

The common recycling methods of composite materials are mainly pyrolysis, crushing and incineration. The three methods do not meet the environmental requirements of energy saving and emission reduction, and cannot realize the recycling and reuse of printing filaments in composite materials. Therefore, it is necessary to develop a new recycling method for continuous fiber-reinforced thermoplastic composites waste, reduce the cost of 3D printing technology, realize efficient recycling of continuous fiber-reinforced thermoplastic composites, ensure the performance of recycled continuous fiber printing filaments, and reduce waste 3D printing. Printing composite parts will pollute the environment, and realizing the recycling of continuous fiber printing filament is crucial to the sustainable development of the composite material industry.

At present, the main challenges facing the recycling technology of continuous fiber reinforced thermoplastic 3D printing composites are: the development and research of new recycling devices and recycling processes; the recycled fiber printing filaments are damaged during the recycling process and cannot meet the requirements of reprinting The pyrolysis and combustion methods will produce a large amount of harmful gases during the recovery process and cause secondary pollution.

CN201610397940.8 discloses a method for recycling and remanufacturing 3D printed continuous fiber reinforced composite materials. A heat gun is used to move in the opposite direction of the 3D printing path of the composite material, and the resin matrix is heated to melt to extract the fibers. The heat gun in this way generally starts to heat from the upper layer of the composite material. After the fibers are stripped, part of the resin matrix stays on the top of the composite material and re-solidifies, resulting in a gradual increase in the thickness of the resin matrix on the top of the composite material. The stripping efficiency of the fibers Gradually lower, energy consumption gradually increased.

Contents of the invention

The purpose of the present invention is to provide a recycling method for continuous fiber-reinforced thermoplastic 3D printing composite materials, which can improve the fiber stripping efficiency without increasing energy consumption, and can recycle resin matrix materials.

The object of the present invention is achieved in the following way: the recycling method of continuous fiber reinforced thermoplastic 3D printing composite material, the composite material to be recycled is fixed on the bottom of a horizontal support plate, and a receiving tank is arranged below the composite material;

Move the heating head to the lower surface of the composite material, use the mechanical arm to drive the heating head to move in the opposite direction of the 3D printing of the composite material, the heating head will melt the resin matrix, and use the traction mechanism to peel off the fibers in the melting area of the resin matrix, and the melted The resin matrix falls down into the spout.

Further, the traction mechanism includes a recovery roller, a forming die, and a guide roller, and the fiber passes through the guide roller and the forming die in sequence, and then is wound on the recovery roller.

Further, the composite material to be recovered is fixed on the lower surface of the horizontal support plate through a clamping mechanism, and the clamping mechanism includes a vertical first clamping plate, a vertical second clamping plate, a first fixing frame and a second fixing frame , the first clamping plate and the second clamping plate are parallel to each other, a clamping cavity is formed between the first clamping plate and the second clamping plate, the upper ends of the first clamping plate and the second clamping plate are slidably connected with the horizontal support plate, the first clamping plate A fixed frame is provided with a first push rod threaded with the first fixed frame, and the second fixed frame is provided with a second push rod threaded with the second fixed frame, and the end of the first push rod contact with the first splint, and the end of the second push rod is in contact with the second splint;

When fixing the composite material, put the composite material into the clamping cavity, turn the first push rod and the second push rod, push the first splint and the second splint to move towards the composite material, until the first splint and the second splint are pressed together both sides of the material.

Further, anti-skid bosses are provided on the clamping surfaces of the first clamping plate and the second clamping plate.

Further, a tungsten slurry heater is arranged inside the heating head.

Further, the heating head is provided with a temperature sensor and a pressure sensor.

Further, when recycling, the heating head is inserted between the fibers of the lowest layer of the composite material and the second-to-last layer of fibers, and then moves in the opposite direction of the 3D printing of the composite material to melt the resin matrix outside the fibers of the lowest layer and make the lowermost layer Fiber stripping.

The beneficial effects of the present invention are: the present invention fixes the composite material to be recycled on the lower surface of the horizontal support plate, strips the fibers of the composite material to be recycled from bottom to top during recycling, and the melted resin matrix material drops under the action of gravity It falls into the receiving trough below to prevent the resin matrix from accumulating on the surface of the composite material to be recycled and cause the thickness of the resin matrix to gradually increase. The power of the heating head can be kept stable to avoid increased energy consumption without affecting the fiber stripping efficiency. In addition, part of the resin matrix can also be recycled and reused, which improves recycling efficiency.

Description of drawings

Fig. 1 is the overall schematic diagram of the present invention;

Fig. 2 is a schematic cross-sectional view of A-A in Fig. 1;

Fig. 3 is a schematic diagram of the heating head of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

In the recycling method of continuous fiber reinforced thermoplastic 3D printing composite materials of the present invention, the composite material 1 to be recycled is fixed on the lower surface of a horizontal support plate 2, and a receiving tank 3 is arranged below the composite material 1;

Move the heating head 5 to the bottom of the composite material 1, and use the mechanical arm 4 to drive the heating head 5 to move in the opposite direction of the 3D printing of the composite material 1. The heating head 5 melts the resin matrix, and uses the traction mechanism to melt the resin matrix. The fibers 6 are peeled off, and the molten resin matrix falls down into the receiving tank 3 .

As shown in FIG. 1 , the horizontal support plate 2 adopts a metal plate with a certain thickness and is installed on a bracket so that the horizontal support plate 2 is located at an appropriate height. The receiving tank 3 is naturally placed under the horizontal support plate 2 for receiving the dripping molten resin matrix. The receiving trough 3 adopts a trough body made of metal materials such as aluminum alloy, which can withstand a certain high temperature. The robot arm 4 can be an existing commonly used robot arm, which can move in a certain range of three-dimensional space, thereby driving the heating head 5 to move in the opposite direction of the 3D printing of the composite material 1 .

The heating head 5 can be an electric heating head, and an electric heating wire is arranged inside. Preferably, as shown in FIG. 3 , a tungsten slurry heater 15 is arranged inside the heating head 5 . The tungsten slurry heater 15 generates high temperature after being energized, which can melt the resin matrix. In order to control the heating temperature of the tungsten paste heater 15 for melting different resin substrates, the heating head 5 is provided with a temperature sensor 16 .

The pulling mechanism is used to pull the fiber 6 so that the fiber 6 is peeled off from the composite material 1 . The traction mechanism specifically includes a recovery roller 7 , a forming die 8 and a guide roller 9 , and the fiber 6 passes through the guide roller 9 and the forming die 8 in turn and is wound on the recovery roller 7 . The recovery roller 7 rotates under the drive of a motor and other equipment, thereby pulling the fiber 6 to be wound up and providing the power for the fiber 6 to be stripped. The forming die 8 has a passage for the fiber 6 to pass through and a heating mechanism inside. When the fiber 6 passes through the passage, the resin matrix remaining on the fiber 6 is melted and scraped off. A container for receiving the resin matrix may also be provided below the forming die 8, and the scraped resin matrix flows along the channel to the channel opening and drops into the container, further realizing the recovery of the resin matrix. The guide roller 9 is used for turning the fiber 6 to make the fiber 6 move along the set direction.

The composite material 1 to be recycled is fixed on the lower surface of the horizontal support plate 2 by a clamping mechanism. As shown in Figure 2, the clamping mechanism includes a vertical first clamping plate 9, a vertical second clamping plate 10, a first The fixed frame 11 and the second fixed frame 12, the first clamping plate 9 and the second clamping plate 10 are parallel to each other, a clamping cavity is formed between the first clamping plate 9 and the second clamping plate 10, and the first clamping plate 9 and the second clamping plate 10 are parallel to each other. The upper ends of the two splints 10 are slidably connected with the horizontal support plate 2, the first push rod 13 threaded with the first fixed mount 11 is provided on the first fixed mount 11, and the first push rod 13 connected with the first fixed mount 11 is provided on the described second fixed mount 12. The second push rod 14 that is threadedly connected to the two fixed mounts 12, the end of the first push rod 13 is in contact with the first splint 9, and the end of the second push rod 14 is in contact with the second splint 10;

When fixing the composite material 1, put the composite material 1 into the clamping cavity, turn the first push rod 13 and the second push rod 14, and push the first splint 9 and the second splint 10 to move toward the composite material 1 until the first splint 9 and the second splint 10 to press the two sides of the composite material 1. There are four first push rods 13 and two second push rods 14, which can ensure sufficient pressing force. The upper ends of the first clamping plate 9 and the second clamping plate 10 can be provided with a dovetail-shaped slide block, and the lower surface of the horizontal support plate 2 can be provided with a dovetail-shaped chute, and the slide block and the chute can be slidably matched. The clamping surfaces of the first splint 9 and the second splint 10 are provided with anti-skid bosses, which can improve the stability of the composite material 1 .

The existing technology only uses the heat of hot air to melt the resin matrix, but does not provide the force to promote the peeling of the fibers 6, and the efficiency is relatively low. In order to improve the peeling efficiency, when recycling, first insert the heating head 5 into the fiber 6 of the lowest layer of the composite material 1 and Between the penultimate layer of fibers 6 , and then move along the opposite direction of the 3D printing of the composite material 1 , so that the resin matrix outside the lowermost layer of fibers 6 is melted and the lowermost layer of fibers 6 is peeled off. After the fibers 6 of the lowest layer are stripped, the fibers 6 of the penultimate layer become the fibers 6 of the bottom layer, and the above-mentioned method is repeated for stripping.

While the heating head 5 is heating the resin matrix, it also provides a peeling force, so that the lowermost layer of fibers 6 is separated from the penultimate layer of fibers 6 faster, thereby reducing the peeling resistance of the lowermost layer of fibers 6, which can realize The lowermost fiber 6 is stripped faster, thereby improving the stripping efficiency. In order to facilitate the control of the peeling force at the end of the heating head 5 , a pressure sensor 17 is also provided at the end of the heating head 5 . The heating temperature and the magnitude of the peeling force can be adjusted according to the detection results of the pressure sensor 17 and the temperature sensor 16, so as to control the peeling speed of the fiber 6. In order to reduce the resistance of the heating head 5 entering the resin matrix, the end of the heating head 5 is tapered, and its thickness gradually increases from the front to the rear.

In summary, the present invention realizes the recycling of part of the resin matrix, improves the recycling efficiency of waste continuous fiber reinforced thermoplastic 3D printing composite materials, improves the recycling efficiency, and reduces the recycling cost.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. The recovery method of the continuous fiber reinforced thermoplastic 3D printing composite material is characterized by comprising the following steps: fixing a composite material (1) to be recycled at the bottom of a horizontal support plate (2), and arranging a material receiving groove (3) below the composite material (1);

the heating head (5) is moved to be in contact with the lower surface of the composite material (1), the mechanical arm (4) is used for driving the heating head (5) to move along the reverse direction of 3D printing of the composite material (1), the heating head (5) melts the resin matrix, the fiber (6) in the melting area of the resin matrix is peeled off by the traction mechanism, and the melted resin matrix falls downwards into the material receiving groove (3).

2. The method of recycling a continuous fiber reinforced thermoplastic 3D printing composite according to claim 1, characterized in that: the traction mechanism comprises a recovery roller (7), a forming opening die (8) and a guide roller (9), and the fibers (6) sequentially pass through the guide roller (9) and the forming opening die (8) and then are wound on the recovery roller (7).

3. The method of recycling a continuous fiber reinforced thermoplastic 3D printing composite according to claim 1, characterized in that: the composite material (1) to be recycled is fixed on the lower surface of a horizontal support plate (2) through a clamping mechanism, the clamping mechanism comprises a vertical first clamping plate (9), a vertical second clamping plate (10), a first fixing frame (11) and a second fixing frame (12), the first clamping plate (9) and the second clamping plate (10) are parallel to each other, a clamping cavity is formed between the first clamping plate (9) and the second clamping plate (10), the upper ends of the first clamping plate (9) and the second clamping plate (10) are in sliding connection with the horizontal support plate (2), a first push rod (13) in threaded connection with the first fixing frame (11) is arranged on the first fixing frame (11), a second push rod (14) in threaded connection with the second fixing frame (12) is arranged on the second fixing frame (12), the end of the first push rod (13) is in contact with the first clamping plate (9), and the end of the second push rod (14) is in contact with the second clamping plate (10);

when the composite material (1) is fixed, the composite material (1) is placed into the clamping cavity, the first push rod (13) and the second push rod (14) are rotated, the first clamping plate (9) and the second clamping plate (10) are pushed to move towards the composite material (1), and the first clamping plate (9) and the second clamping plate (10) are pressed against two side faces of the composite material (1).

4. The method of recycling a continuous fiber reinforced thermoplastic 3D printed composite according to claim 3, characterized in that: and anti-skidding bosses are arranged on the clamping surfaces of the first clamping plate (9) and the second clamping plate (10).

5. The method of recycling a continuous fiber reinforced thermoplastic 3D printed composite according to claim 1, characterized in that: and a tungsten slurry heater (15) is arranged in the heating head (5).

6. The method of recycling a continuous fiber reinforced thermoplastic 3D printed composite according to claim 5, characterized in that: and a temperature sensor (16) and a pressure sensor (17) are arranged on the heating head (5).

7. The method of recycling a continuous fiber reinforced thermoplastic 3D printing composite according to claim 1, characterized in that: during recovery, the heating head (5) is inserted between the lowest layer fiber (6) and the penultimate layer fiber (6) of the composite material (1), and then the heating head moves along the direction opposite to the 3D printing direction of the composite material (1), so that the resin matrix outside the lowest layer fiber (6) is melted, and the lowest layer fiber (6) is peeled.

Images