WO2023124037A1

WO2023124037A1 - Method and device for forming continuous fiber composite material by combining additive and subtractive manufacturing

Info

Publication number: WO2023124037A1
Application number: PCT/CN2022/107547
Authority: WO
Inventors: 单忠德; 林初明; 范聪泽; 宋文哲; 刘琳; 张蕾; 刘东榕
Original assignee: 南京航空航天大学; 山东中康国创先进印染技术研究院有限公司
Priority date: 2021-12-28
Filing date: 2022-07-23
Publication date: 2023-07-06
Also published as: CN114683534A

Abstract

The present invention provides a method and device for forming a continuous fiber composite material by combining additive and subtractive manufacturing. According to the present invention, a resin filament and a continuous fiber are fed into a printing head and are melt and deposited, to first form a continuous fiber reinforced composite material by additive manufacturing by means of melt deposition forming; and after forming is completed, size and morphology data acquisition is performed to obtain the actual size of a part; a subtractive path is planned, and subtractive forming is carried out by a laser. According to the present invention, additive and subtractive forming is used for the continuous fiber composite material, additive forming is carried out by means of melt deposition, laser subtractive machining is performed, so that a device structure is simplified, machining stress and mechanical deformation are reduced, three-dimensional measurement and subtractive planning are carried out on the part, the automation degree is improved, and forming precision of the part made of the continuous fiber composite material is comprehensively improved.

Description

A continuous fiber composite material forming method and device used for adding and subtracting materials

technical field

The invention belongs to the technical field of composite manufacturing of additive and subtractive materials, and in particular relates to a composite forming method of additive and subtractive materials of continuous fiber composite materials and a device used therefor.

Background technique

Due to its excellent performance, the research and development of composite materials presents a rapid growth trend, and two or more materials can complement each other to obtain more superior performance. Traditional continuous fiber composite molding and manufacturing generally require a series of complex and inefficient processes, which limit the shape and application range of continuous fiber composite materials. At the same time, the process includes high temperature, chemical decomposition, etc., which pollutes the environment. .

Fused deposition modeling (FDM) heats the resin filament at the printing nozzle to melt it, and then the material is extruded under the action of the extrusion mechanism, gradually cooled and solidified, and deposited on the printing platform. After one layer is printed, the next layer is carried out Printing, layer by layer superposition to get the final entity. Compared with the traditional molding process of fiber-reinforced resin-based composite materials, FDM technology is used for 3D printing of continuous fiber composite materials. The molding process is simple, the material utilization rate is high, and it does not depend on mold manufacturing and molding, and the integration of complex structural parts can be realized. take shape. However, there is a step effect in the parts printed by the FDM process, and the forming efficiency is limited by the size of the part. The larger the thickness of the layer, the faster the part is formed, but the more serious the step effect is, the dimensional accuracy and surface quality will be affected.

Aiming at the error of forming accuracy, the compound manufacturing method of adding and subtracting materials can be adopted, but the traditional method of reducing materials such as turning and milling needs to design fixtures to fix the parts, which increases the complexity of the equipment, the structure of the working platform is complicated, and the parts fixed by the fixtures will also cause Parts are deformed by force, and different resin and fiber materials need to be researched and optimized for tool materials and cutting processes. The process is complex and time-consuming, and improper selection of cutting processes and tool materials may damage parts.

Contents of the invention

In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to research and design a new continuous fiber composite material forming method combined with addition and subtraction materials, so as to improve the forming accuracy of FDM process printing continuous fiber composite material parts.

In order to achieve the above object, the present invention proposes a continuous fiber composite material forming method of adding and subtracting materials, the method comprising the following steps:

(1) Convert the 3D model of the part to be manufactured into an STL format file, slice the STL format file to obtain the contour information of each layer, and plan the additive path;

(2) Continuous fibers and thermoplastic resin filaments enter the printing nozzle, are extruded by melt extrusion, and deposited on the forming platform. According to the current layer information, the nozzle moves according to the designed additive path to print continuous fiber and thermoplastic resin materials. After the printing of the current layer is completed, the forming platform is lowered to a height, and this step is repeated to complete the additive manufacturing of parts;

(3) Detect the actual size of the part through the three-dimensional measuring device, compare it with the ideal model size of the part, and collect the appearance data information of the part at the same time, obtain the surface defect of the part, and plan the material reduction according to the obtained size difference data and appearance data path;

(4) Use the laser to perform laser material reduction and contour refinement on the part according to the planned material reduction path, so that the final formed part is consistent with the ideal part size, and complete the part addition and subtraction material manufacturing process.

As a further preference, when the additive path is planned, the outline path is biased outward, so that the actual additive manufacturing part size is slightly larger than the ideal model size, leaving a margin for the subtractive manufacturing; the continuous fiber is carried out inside the layer slice outline Infill printing, outlines are printed in pure thermoplastic resin-based materials.

As a further preference, the continuous fibers include one or more of carbon fibers, Kevlar fibers, glass fibers, carbon nanotube fibers, basalt fibers, aramid fibers, ceramic fibers, and metal fibers.

As further preferred, the thermoplastic resin includes polylactic acid material, ABS resin material, nylon material, polycarbonate material, polyether ether ketone material, polyarylether ketone material, polyamide sub-material, PPSU material, polyether imide One or more of amine materials and polyphenylene sulfone resin materials.

Compared with the prior art, the present invention has the advantages of:

(1) The additive and subtractive material composite manufacturing method is adopted for continuous fiber composite materials, which improves the forming accuracy of FDM process printing; the laser subtractive material processing method is adopted to simplify the equipment structure, and there is no need for fixture design or special forming platform design;

(2) The part slicing process and the continuous fiber filling path are optimized, the fiber is only reinforced inside, and the laser processing allowance is left on the contour, which avoids the damage of the laser to the fiber;

(3) The laser belongs to non-contact processing, which reduces the processing stress and mechanical deformation, can be completed instantaneously, and has high processing efficiency; the space control and time control of the laser are very good, and the freedom of the material and shape of the processing object is very good. Large, the process of process research is greatly simplified compared to tool cutting.

(4) A non-contact binocular camera is used for part size measurement and material reduction path planning, without manual observation and addition of material reduction paths, which improves the degree of automation, avoids the interference of measurement on parts, and determines the The trajectory and position of the subtractive manufacturing are determined, which provides a basis for the subtractive manufacturing, and further improves the forming accuracy of the parts.

The present invention also provides the device used in the above-mentioned continuous fiber composite material forming method of adding and subtracting materials, adopting the following technical scheme: comprising a forming platform, a frame located on both sides of the forming platform, a first beam and a second beam located on the frame , a wire feeding mechanism and a printing nozzle located on the first beam, and a laser located on the second beam; the frames on both sides are provided with a first longitudinal beam and a second longitudinal beam extending perpendicularly to the first beam, and the The second longitudinal beam is located above the first longitudinal beam; the first transverse beam and the second transverse beam both straddle the first longitudinal beams on both sides and reciprocate along the extending direction of the first longitudinal beam; the printing nozzle extends along the first transverse beam The laser moves back and forth in the extending direction of the second beam; the first longitudinal beams on both sides are respectively provided with a three-dimensional measuring device; the three-dimensional measuring device moves back and forth along the extending direction of the first longitudinal beam.

As a further preference, the three-dimensional measurement device is a camera-type structured light three-dimensional scanner.

As a further preference, the laser includes one of a femtosecond laser, a picosecond laser, and a nanosecond laser.

As a further preference, the printing nozzle is driven by the first beam to move according to the material-adding path, and the thermoplastic resin material is melted after entering the printing nozzle through the wire feeding mechanism, impregnated with continuous carbon fibers, and deposited on the forming platform together. The current layer is completed to form the next layer, and the additive forming process is completed layer by layer. When forming, only thermoplastic resin is used for additive forming on the contour of the part, and thermoplastic resin and continuous fiber are used for additive forming inside the contour.

Description of drawings

Fig. 1 is a flow chart of the forming method of the continuous fiber composite material combined with the addition and subtraction materials implemented in the present invention.

Figure 2 is a schematic diagram of additive path planning.

Fig. 3 is a perspective view of a device used in the continuous fiber composite material forming method of adding and subtracting materials.

Figure 4 is a diagram of the additive manufacturing process for the device used.

Figure 5 is a schematic of the subtractive manufacturing process for the device used.

Detailed ways

In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with examples, but the content of the present invention is not limited to the following examples. In addition, those skilled in the art may make various changes or modifications to the present invention after reading the content described in the present invention, and these equivalent forms are also applicable to the scope defined by the appended claims of the present application.

Embodiment one

As shown in Figure 1 and Figure 2, the process flow of the continuous fiber composite material forming method of additive and subtractive materials is shown in Figure 1. The continuous fiber is selected from carbon fiber, and the thermoplastic resin matrix material is selected from polylactic acid material. The additive and subtractive materials are combined according to the following steps.

(1) Model the required 3D parts, convert the 3D model into STL format files, and import the STL format files into slicing software for slicing to obtain the contour information of each layer.

(2) Plan the additive path for each layer slice information, and set the printing process parameters, in which the outline path is offset by a certain distance, which is an integer multiple of the nozzle diameter of the melt nozzle, so that the actual additive manufacturing part size is slightly It is larger than the ideal model size, leaving a margin for subtractive manufacturing. The outline is printed with pure polylactic acid material, and the interior is filled with continuous carbon fiber. The schematic diagram of the additive path planning is shown in Figure 2.

(3) The continuous carbon fiber and polylactic acid filament enter the printing nozzle under the action of the wire feeding mechanism, the printing nozzle is heated above the melting point of polylactic acid, the polylactic acid is heated to impregnate the continuous carbon fiber, and is extruded and deposited on the forming platform. According to the current layer information, the nozzle first prints the continuous fiber internal filling path according to the designed additive path, and then prints the pure resin outline part. After the printing is completed, the forming platform is lowered by a height, and the next layer of additive printing is performed. material manufacturing.

(4) The photo-type structured light 3D scanner detects the actual size of the part, constructs the actual 3D part model, and compares it with the ideal model size of the part, and at the same time collects the appearance and shape data information of the part through image recognition and other programs to obtain the part surface Defect forms and defect positions such as polylactic acid protrusions and wire drawing, and the material reduction path is planned according to the obtained size difference data and appearance data.

(5) Use the femtosecond laser for material reduction processing, set the laser material reduction process parameters, the laser is driven by the movement mechanism to perform laser material reduction on the parts according to the planned material reduction path, and then perform a contour refinement after material reduction , so that the final molded part is consistent with the ideal part size, and a better surface quality is obtained, and the part addition and subtraction material manufacturing process is completed.

Embodiment two

Please refer to FIG. 3 , this embodiment is the device used in the continuous fiber composite material forming method using the addition and subtraction materials in the first embodiment. The device includes a forming platform 12, a frame 3 located on both sides of the forming platform, a first beam 8 and a second beam 9 located on the frame 3, a second wire feeding mechanism 6 and a printing nozzle 7 located on the first beam 8, and a The laser device 10 on the second crossbeam 9, the wire material disc 4 installed on the side frame, the fiber take-up and release shaft 2, and the first wire feeding mechanism 5. The forming platform 12 and the print head 7 can be preheated.

The frames on both sides are provided with a first longitudinal beam 13 and a second longitudinal beam 14 extending perpendicular to the first cross beam 8 . The second longitudinal beam 14 is located above the first longitudinal beam 13 . Both the first beam 8 and the second beam 9 straddle the first longitudinal beams 13 on both sides and reciprocate along the extending direction of the first longitudinal beams 13 . The print head 7 reciprocates along the extending direction of the first beam 8 . The laser 10 moves back and forth in the extending direction of the second beam 9 . A three-dimensional measuring device is respectively provided on the first longitudinal beams 13 on both sides; the three-dimensional measuring device moves back and forth along the extending direction of the first longitudinal beams 13 . In this embodiment, the three-dimensional measuring devices on both sides are the first binocular camera 1 and the second binocular camera 11 respectively.

When the device is used to shape the material, the polylactic acid resin filament is drawn out from the wire tray 4, passed through the first wire feeding mechanism 5, and introduced into the printing nozzle 7, and the continuous carbon fiber is drawn out from the fiber take-up and release shaft 2, and passed through the first wire feeding mechanism 5. The second wire feeding mechanism 6 is introduced into the print head 7 .

The printing nozzle 7 is driven by the first movement mechanism 8 to move according to the material-adding path, the first wire feeding mechanism 5 and the second wire feeding mechanism 6 perform wire feeding, and the polylactic acid filament enters the printing nozzle 7 and is melted and impregnated Continuous carbon fibers are deposited on the forming platform 12 together to complete the current layer and form the next layer, and the additive forming process is completed layer by layer. When forming, the part outline is only made of thermoplastic resin for additive forming, and the inside of the outline is made of thermoplastic resin and fiber. For additive forming, see Figure 4 for the additive process. The second wire feeding mechanism 6 can realize the functions of fiber tensioning and shearing, and can shear the fibers to realize the pure resin additive molding of the outline part of the part.

The first binocular camera 1 and the second binocular camera 11 detect the actual size of the part, establish the actual three-dimensional model size of the part and compare it with the ideal model size of the part, and at the same time collect the appearance and shape data information of the part, and obtain the surface protrusions of the part, For defects such as wire drawing, the material reduction path is planned according to the obtained size difference data and appearance data, and the process parameters of the material reduction process are set;

Driven by the second motion mechanism 9 , the laser 10 performs rough laser material reduction on the pure resin material at the contour of the part according to the planned material reduction path, and then conducts a contour refinement after the rough material reduction is completed. The material reduction process is shown in FIG. 5 .

Claims

A continuous fiber composite material forming method of increasing and subtracting materials is characterized in that, comprising the following steps:

(1) Convert the 3D model of the part to be manufactured into an STL format file, slice the STL format file to obtain the contour information of each layer, and plan the additive path;

(2) Continuous fibers and thermoplastic resin filaments enter the printing nozzle, are extruded by melt extrusion, and deposited on the forming platform. According to the current layer information, the nozzle moves according to the designed additive path to print continuous fiber and thermoplastic resin materials. After the printing of the current layer is completed, the forming platform is lowered to a height, and this step is repeated to complete the additive manufacturing of parts;

(3) Detect the actual size of the part through the three-dimensional measuring device, compare it with the ideal model size of the part, and collect the appearance data information of the part at the same time, obtain the surface defect of the part, and plan the material reduction according to the obtained size difference data and appearance data path;

(4) Use the laser to perform laser material reduction and contour refinement on the part according to the planned material reduction path, so that the final formed part is consistent with the ideal part size, and complete the part addition and subtraction material manufacturing process.
According to claim 1, a continuous fiber composite material forming method based on additive and subtractive materials, characterized in that, when the additive path is planned, the contour path is biased outward, so that the actual additive manufacturing part size is slightly larger than the ideal Model size, with allowance for subtractive manufacturing; continuous fibers are infill printed inside the ply slice outlines, which are printed in pure thermoplastic resin-based materials.
The continuous fiber composite material forming method of adding and subtracting materials according to claim 1, wherein the continuous fiber comprises carbon fiber, Kevlar fiber, glass fiber, carbon nanotube fiber, basalt fiber, aramid fiber, One or more of ceramic fibers and metal fibers.
The continuous fiber composite material forming method of adding and subtracting materials according to claim 1, wherein the thermoplastic resin comprises polylactic acid material, ABS resin material, nylon material, polycarbonate material, polyether ether ketone material, One or more of polyaryletherketone materials, polyamide sub-materials, PPSU materials, polyetherimide materials, and polyphenylene sulfone resin materials.
A device used in the continuous fiber composite material forming method of adding and subtracting materials according to any one of claims 1 to 4, characterized in that it includes a forming platform, frames located on both sides of the forming platform, and a frame located on the frame. The first beam and the second beam, the wire feeding mechanism and the print head on the first beam, and the laser on the second beam; the frames on both sides are provided with the first longitudinal beam and the vertical extension of the first beam. The second longitudinal beam, the second longitudinal beam is located above the first longitudinal beam; the first cross beam and the second cross beam both straddle the first longitudinal beams on both sides and reciprocate along the extending direction of the first longitudinal beam; The printing nozzle moves back and forth along the extending direction of the first beam; the laser moves back and forth in the extending direction of the second beam; a three-dimensional measuring device is respectively installed on the first longitudinal beams on both sides; the three-dimensional measuring device reciprocates along the extending direction of the first longitudinal beam move.
The device according to claim 5, wherein the three-dimensional measurement device is a camera-type structured light three-dimensional scanner.
The device according to claim 5, wherein the laser comprises one of a femtosecond laser, a picosecond laser, and a nanosecond laser.
The device according to claim 5, characterized in that the printing nozzle is driven by the first beam to move according to the material-adding path, and the thermoplastic resin material is melted after entering the printing nozzle through the wire feeding mechanism, and impregnated with continuous carbon fiber , are deposited together on the forming platform, the current layer is completed and the next layer is formed, and the additive forming process is completed layer by layer. When forming, only thermoplastic resin is used for the part contour, and thermoplastic resin and continuous fiber are used for the internal contour. take shape.
The device according to claim 5, wherein the laser comprises one of a femtosecond laser, a picosecond laser, and a nanosecond laser.