A method for printing composite material workpieces based on FDM molding.

Abstract

This invention discloses a method for printing composite material workpieces based on FDM molding, comprising: constructing a three-dimensional model of the composite material workpiece to be printed, and performing layer-by-layer slicing to obtain two-dimensional slicing information; determining the printing strategy for the composite material workpiece; filling reinforcing material into the coverage area of ​​a thermoplastic sheet matrix, compacting the thermoplastic sheet matrix filled with reinforcing material, and then performing filament winding and overmolding of the compacted thermoplastic sheet matrix to obtain the composite material; setting the printing parameters of the FDM molding equipment, and controlling the FDM molding equipment to melt and deposit the composite material layer by layer to obtain the composite material workpiece. This method achieves differentiated performance requirements for composite material workpieces, ensures printing stability, and thus improves the overall performance and molding quality of the workpiece.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing and relates to a method for printing composite material workpieces based on FDM molding. Background Technology

[0002] 3D printing, also known as additive manufacturing, is a technology that uses a digital model to create three-dimensional solids by layer-by-layer accumulation of specific materials. Compared with traditional molding methods, this technology eliminates the need for molds for prototyping and machining, offering advantages such as short production cycles, freeform molding, and low production costs. It has been widely applied in aerospace, automotive, medical, and bioengineering fields. Among these methods, Fused Deposition Modeling (FDM) has become a commonly used 3D printing method due to its high material utilization, ability to directly create colored prototypes, and ease of operation. Its working principle involves heating and melting a filament of thermoplastic material through a nozzle. The nozzle moves according to the programmed cross-sectional contour and printing path, and the extruded material solidifies layer by layer to form a three-dimensional solid. Currently, most existing FDM printing materials are single thermoplastic materials, which are prone to warping, deformation, and cracking during the molding process. This results in limited performance in terms of strength, wear resistance, electrical conductivity, and thermal conductivity, failing to meet the requirements of high-performance structural components.

[0003] To improve the mechanical properties and functional characteristics of molded parts, reinforcing materials are typically introduced into thermoplastic materials to prepare composite materials. Existing methods mostly involve mixing raw materials to form filaments, which are then printed layer by layer using an FDM printer, or feeding the reinforcing material and hot-melt raw material into a nozzle simultaneously in a specific ratio, allowing the raw material to melt and then encapsulate the reinforcing material before extrusion. These methods have certain limitations. For example, the reinforcing material is often a single material, making it impossible to achieve performance differences in different areas of the same molded part; powdered materials are prone to sedimentation and stratification during mixing, leading to uneven cross-sectional composition of the composite material; the extrusion process requires complete melting of the thermoplastic material, resulting in high energy consumption, and the high-temperature environment can easily cause degradation and aging of some thermoplastic materials; extrusion difficulties and blockages can easily occur at the nozzle; and fiber materials are prone to entanglement and agglomeration in the hot-melt raw material, making uniform dispersion difficult. These problems make it difficult to ensure uniform composition of the composite material, ultimately affecting the quality and performance of the molded part. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite material workpiece printing method based on FDM molding, so as to realize the differentiated performance requirements of composite material workpieces, ensure printing stability, and thus improve the overall performance and molding quality of the workpieces.

[0005] To achieve the above objectives, the present invention employs the following technical solution: A method for printing composite material workpieces based on FDM molding includes the following steps: A three-dimensional model of the composite material workpiece to be printed is constructed, and the three-dimensional model is sliced ​​layer by layer to obtain two-dimensional slice information; Determine the printing strategy for composite material workpieces based on two-dimensional slice information; Based on the two-dimensional slicing information and printing strategy, the reinforcing material is filled into the covering area of ​​the thermoplastic sheet matrix, the thermoplastic sheet matrix filled with the reinforcing material is compacted, and the compacted thermoplastic sheet matrix is ​​wound and wrapped to obtain the composite material. Based on the printing strategy and the material properties of the composite material, the printing parameters of the FDM molding equipment are set. According to the printing strategy and printing parameters, the FDM molding equipment is controlled to melt and deposit the composite material layer by layer to obtain the composite material workpiece.

[0006] Optionally, the process of obtaining two-dimensional slice information includes: Obtain the geometric dimensions, surface quality requirements, composite material type information, and composite material distribution information of the composite material workpiece to be printed; A 3D model is designed based on geometric dimensions, surface quality requirements, composite material types, and composite material distribution information. Perform format conversion for storing 3D models; Preprocessing is performed on the 3D model after format conversion to fix model defects; The placement of the 3D model for printing is determined based on surface quality requirements, support structure design, and molding time. The 3D model is sliced ​​layer by layer according to the printing orientation to obtain the 2D slice information of each 2D contour.

[0007] Optionally, the two-dimensional slice information includes the contour data, size parameters, spatial location information, layer thickness, number of layers, support type, infill path, composite material type information, and composite material distribution information corresponding to the two-dimensional slice.

[0008] Optionally, the process of determining the printing strategy for composite material workpieces includes: The printing range, printing path, infilling strategy, type of reinforcing material, and distribution of reinforcing material for composite workpieces are determined based on two-dimensional slice information. The printing path adopts a partitioned path strategy, which is as follows: an offset path is applied to the outer contour area; a zigzag reciprocating printing method is applied to the inner filling area; and two sets of intersecting straight lines are used to generate a diamond or square grid in the support area.

[0009] Optionally, the printing strategy includes segmented and material-specific printing methods; The process of printing in segments and materials includes: The material distribution information of the 3D model is converted into data on the distribution of multiple types of reinforcing materials and their locations in various regions of the composite workpiece. The location distribution data is transmitted to the FDM molding equipment; FDM molding equipment controls the type and content of reinforcing materials in each area based on location distribution data and printing strategies; The composite material is mapped to the printing path and slice length to perform the printing.

[0010] Optionally, the process of filling the reinforcing material into the coverage area of ​​the thermoplastic sheet matrix includes: The two layers of thermoplastic sheet substrate are transported synchronously and continuously, divided into upper and lower layers. Assemble a hopper between the upper and lower thermoplastic sheet substrates; The hopper conveys the reinforcing material between the upper and lower thermoplastic sheet substrates via a screw-feeding method or a vibration-feeding method. Adjust the conveying rate, filling density, and discharge area position of the reinforcing material to distribute the reinforcing material within the coverage area of ​​the thermoplastic sheet matrix.

[0011] Optionally, the process of compacting the thermoplastic sheet matrix filled with reinforcing material includes: The three-layer composite structure material consisting of the upper and lower thermoplastic sheet matrix filled with reinforcing material and the reinforcing material is transported to the compaction device; The compaction device applies a pressure of 10MPa to 50MPa and a vibration frequency of 30HZ to 100HZ to the three-layer composite material, and heats the three-layer composite material at a temperature of 150℃ to 250℃.

[0012] Optionally, the process for preparing the composite material includes: The compacted three-layer composite structural material is conveyed to the spiral winding device; The spiral winding device rolls and wraps the thermoplastic sheet matrix from both sides toward the center of the three-layer composite material to cover the reinforcing material. The spiral winding device has a spiral angle of 360°, a rotation speed of 10r / min to 40r / min, and a winding tension of 1N to 3N.

[0013] Optionally, the process of setting the printing parameters for the FDM molding equipment includes: Adjust the position of the printing platform and preheat it to a temperature of 50℃~110℃; set the layer thickness to 0.1mm~0.4mm; the layer height to 0.1mm~0.4mm; the printhead temperature to 180℃~280℃; and the printing speed to 30mm / s~80mm / s.

[0014] Optionally, the process of obtaining composite material workpieces includes: The composite material is fed into the drive unit at a constant speed via a wire storage device; The motor inside the drive unit drives the rotation to feed the composite material toward the heating element; The heating element heats and melts the composite material; The composite material is extruded from a nozzle after being heated and melted; The printhead melts and deposits a support structure on the printing platform; The printing platform descends a distance via connecting rods according to the layer thickness increments; The nozzle melts and deposits layer by layer along the printing path and filling path to produce composite material workpieces.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention uses two layers of thermoplastic sheets as the matrix, with reinforcing material filled in the middle. The sheets are then spirally wound from both sides towards the center to form filaments. This physical coating method avoids matrix aging caused by prolonged mixing at extremely high temperatures. Furthermore, the thermoplastic sheets, through their own curling during winding, firmly lock the powder or fibers inside, maintaining a predetermined uniform distribution. This completely solves the problems of reinforcing material agglomeration and uneven dispersion. Simultaneously, due to the stable shrinkage rate of the thermoplastic sheets, it effectively suppresses uneven shrinkage of the internal reinforcing material during molding, significantly reducing the risk of warping, delamination, and cracking in the final printed workpiece.

[0016] Furthermore, prior to spiral winding, the three-layer composite structure filled with reinforcing material is compacted under specific pressure, vibration frequency, and temperature. High-frequency vibration causes the internal powder or fiber particles to rearrange and tightly fill the gaps; suitable heating temperature keeps the thermoplastic sheet in a semi-molten or softened state, increasing surface adhesion; and the external pressure forces out the air between the material layers. This process ensures a gapless, tight bond between the upper and lower thermoplastic sheets and the middle reinforcing layer, eliminating internal delamination defects and greatly improving the bonding strength between the composite structure interfaces, thereby guaranteeing the overall mechanical properties of the printed part.

[0017] Furthermore, the feed rate and type of reinforcing material are adjusted in real time by a quantitative feeding mechanism, and the prepared filament is directly fed into the FDM printhead through a filament storage device. Since the filament is continuously customized online, the computer can precisely control the composition of the reinforcing material in different sections of the filament based on the 3D model slicing information (for example, one section coated with carbon fiber for tensile strength, and another coated with copper powder for conductivity), thus enabling the printing of multiple types of composite materials from a single filament. In addition, because the prepared composite filament enters the printer directly without needing to be wound onto a feed tray like traditional filaments, it physically avoids the huge internal stress, springback deformation, and subsequent filament feeding jams and breakage problems caused by bending. This not only enables personalized customization of complex workpieces with varying performance across multiple areas but also greatly improves the smoothness of filament feeding and printing stability of the FDM equipment. Attached Figure Description

[0018] Figure 1 This is a flowchart of the composite material workpiece printing method based on FDM molding of the present invention; Figure 2 This is a schematic diagram of the printing strategy of the present invention; Figure 3 This is a schematic diagram illustrating the preparation of the composite material according to the present invention; Figure 4 This is a schematic diagram of the integrated structure of the FDM printing device and the composite material of the present invention.

[0019] Wherein: 1-hopper; 2-thermoplastic sheet substrate; 3-compacting device; 4-spiral winding device; 5-composite material; 6-filament storage device; 7-drive device; 8-heating element; 9-nozzle; 10-composite material workpiece; 11-support structure; 12-printing platform; 13-connecting rod. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] like Figure 1 As shown, this embodiment provides a method for printing composite material workpieces based on FDM molding, including the following processes: S1. Construct a three-dimensional model of the composite material workpiece 10 to be printed, store and convert it through a specific format file, and perform layer-by-layer slicing processing on the three-dimensional model to obtain two-dimensional slicing information; S2, determine the printing strategy for the composite material workpiece 10 based on the slice information; S3, according to the slicing information and printing strategy, the reinforcing material is filled into the covering area of ​​the thermoplastic sheet matrix 2, and the material is tightly bonded by compaction treatment. The composite material is prepared by filament wrapping molding process. S4, Set the printing parameters of the FDM molding equipment according to the printing strategy and the material properties of the composite material; S5. According to the preset printing strategy and printing parameters, the composite material is melt-deposited layer by layer using an FDM molding equipment to obtain the composite material workpiece 10.

[0023] The specific process of the above method is as follows: S1. Obtain the geometric dimensions, surface quality requirements, and composite material type and distribution information of the composite material workpiece 10 to be printed. Design a three-dimensional model of the composite material workpiece 10 in the computer, save and convert the three-dimensional model in STL format, and process it with professional slicing software. The process is as follows: First, preprocess the STL file to repair model defects to ensure there are no voids, intersections, or overlapping surfaces; then, comprehensively consider the workpiece surface quality, support structure design, and molding time to determine the printing placement of the three-dimensional model; finally, slice the preprocessed three-dimensional model layer by layer to obtain the two-dimensional contour slice information of each layer.

[0024] The slice information includes the contour data, size parameters, spatial location information, layer thickness, number of layers, support type, filling path, and composite material type and distribution information corresponding to each two-dimensional slice, which guides the movement of the nozzle and material control during the printing process.

[0025] S2, as Figure 2 As shown, the printing strategy for the composite material workpiece 10 is determined based on the slice information.

[0026] Based on the slicing information from S1, the printing range, printing path, infill strategy, and type and distribution of reinforcing material for the composite workpiece are determined. Specifically, the printing range is determined in the slicing software by selecting the printer model and observing the view to determine if the model exceeds the printing frame.

[0027] The printing path adopts a partitioned path strategy, including an outer contour area, an internal filling area, and a support structure area. An offset path is used for printing in the outer contour area of ​​the workpiece, a zigzag reciprocating printing method is used in the internal filling area, and two sets of intersecting straight lines are used to form a regular rhombus or square grid for printing in the support area.

[0028] The types and distribution of composite materials are achieved through segmented, material-specific printing. The specific process is as follows: The computer converts the material distribution information of the 3D model of the composite material into data on the distribution of multiple types of reinforcing materials and their locations in each region of the printed workpiece, and transmits this data to the FDM molding equipment. Based on this data and a preset printing strategy, the driver program of the FDM molding equipment controls the types and amounts of reinforcing materials required for each printing region. The composite material 5 is then mapped to the printing path and slice length, and printed according to the slice information and printing strategy. This method enables multi-material design of the workpiece, meeting the performance differences in different regions.

[0029] S3, according to the slicing information and printing strategy, the reinforcing material is filled into the covering area of ​​the thermoplastic sheet matrix 2, and the material is tightly bonded by compaction treatment. The composite material 5 is prepared by filament wrapping molding process.

[0030] The preparation process of composite material 5 is as follows Figure 3 As shown, the steps are as follows: S31: Feeding control.

[0031] Two layers of thermoplastic sheet substrate 2 are used, which are conveyed synchronously and continuously in two layers by a conveying device. An independent hopper 1 is set between the upper and lower layers of thermoplastic sheet substrate 2. The hopper 1 is used to store and convey reinforcing material. The distribution density of the reinforcing material is adjusted by screw quantitative feeding or vibration feeding, so that the discharge rate of the hopper 1 is flexibly adjustable. By adjusting the conveying rate, filling density and discharge area position of the reinforcing material, uniform distribution of the reinforcing material in the area covered by the two layers of thermoplastic sheet substrate can be achieved. It can also be used to fill in segments and materials according to the needs of the reinforcing area of ​​the composite material workpiece 10 to be printed, thereby meeting the functional requirements of specific areas.

[0032] The reinforcing material is one or more of powder and fiber, wherein the powder material includes, but is not limited to, one or more of metal powder, ceramic powder, and carbon-based nanoparticles; the metal powder is one or more of copper powder, tungsten powder, stainless steel powder, iron powder, and nickel powder; the ceramic powder is one or more of alumina powder, zirconium oxide powder, silicon carbide powder, and silicon nitride powder; and the carbon-based nanoparticles are one or more of graphene powder and carbon nanotube powder. The fiber material is one or more of short fiber and continuous fiber, which can be flexibly selected according to the mechanical properties and molding performance requirements of the composite material workpiece 10 to ensure the compatibility of the reinforcing material with the thermoplastic sheet matrix 2.

[0033] The choice of reinforcing materials is related to the service performance requirements of the workpiece. For structural areas requiring high tensile strength, bending stiffness, and resistance to alternating loads, carbon fiber can be used as the reinforcing material; for workpieces requiring electrical conductivity, thermal conductivity, or lightweighting, metal powder is selected as the reinforcing material; while for surfaces or contact areas requiring high hardness, wear resistance, and high temperature resistance, ceramic powder is selected as the reinforcing material; for thin and functional layers requiring microscale reinforcement or electromagnetic shielding, graphene powder can play a good role in reinforcement and functionalization; when a single reinforcing material cannot meet the comprehensive performance requirements, combinations of fibers and powders, or multiple powders, can be used to achieve a synergistic improvement in mechanical properties and functional characteristics, thereby meeting the multi-objective performance requirements under complex working conditions.

[0034] The thermoplastic sheet substrate 2 is made of one or more of polylactic acid (PLA), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene terephthalate (PETG), nylon (PA), and thermoplastic polyurethane (TPU); wherein the thermoplastic sheet substrate 2 is a long strip continuous sheet with a thickness of 0.05mm to 0.3mm and a width of 2mm to 15mm.

[0035] S32: Compact bonding.

[0036] After the reinforcing material is filled, a three-layer composite structure is obtained. This composite structure uses two upper and lower thermoplastic sheet substrates 2 as the matrix, with the middle layer being the reinforcing material. The composite structure is then conveyed to a compaction device 3, where it is subjected to top and bottom pressure, vibration, and heat treatment. The pressure is 10~50MPa, the vibration frequency is 30~100HZ, and the temperature is 150℃~250℃. Through the combined effect of these parameters, a tight bond is ensured between the upper and lower thermoplastic sheet layers and the middle reinforcing material, without gaps or delamination, thus improving the bonding strength of the composite structure.

[0037] S33: Winding molding.

[0038] The compacted composite material is conveyed to the spiral winding device 4. The spiral winding device 4 gradually rolls and wraps the thermoplastic sheet matrix 2 from both sides to the center, so that the intermediate reinforcing material is tightly wrapped around the thermoplastic sheet matrix 2 to form the composite material 5. The spiral angle is 360°, the rotation speed is 10~40 r / min, and the winding tension is 1~3 N.

[0039] The prepared composite material 5 can achieve the printing of multiple types of composite materials from a single strand by controlling the type and content of reinforcing materials. In addition, the composite material 5 does not require winding on the feed roller or filament spool. It can be stored and fed through the filament storage device 6 in the form of segmented cutting, straight strip storage, boxed stacking, or flexible guided storage according to actual printing needs. When in use, it is directly fed into the drive device 7 and nozzle 9 of the printing equipment, avoiding problems such as bending internal stress, springback deformation, and filament feeding jamming caused by filament spool winding, ensuring the flatness of the filament and the stability of filament feeding, and improving the stability of the formed parts.

[0040] In this step, composite material 5 is completed through an integrated process of coating, compaction, and wire winding. The compaction pressure controls the density of composite material 5 and the matrix, ensuring that composite material 5 does not shift and the wire winding does not disrupt the original distribution, thus maintaining the preset distribution pattern and position.

[0041] S4: Based on the printing strategy and the material properties of the composite material, adjust the position of the printing platform and preheat it to 50℃~110℃. Set the printing parameters, such as layer thickness, nozzle temperature, and printing speed. Optimal parameters are: layer thickness 0.1mm~0.4mm, layer height 0.1mm~0.4mm, nozzle temperature 180℃~280℃, and printing speed 30mm / s~80mm / s. These parameters can be adjusted according to the specific needs of the composite material to ensure good bonding between layers and high-quality molding results during printing.

[0042] S5: According to the preset printing strategy and printing parameters, the composite material is melt-deposited layer by layer using FDM molding equipment to obtain composite material workpiece 10.

[0043] The aforementioned composite material is FDM printed into a composite material workpiece 10, which is formed by... Figure 4 The printing device shown is implemented in this way. The drive device 7, heating device 8 and nozzle 9 move synchronously in the XY plane under the command of the control system to execute the printing path. The connecting rod 13 causes the printing platform 12 to descend layer by layer along the Z-axis to achieve the layer-by-layer stacking of three-dimensional solids.

[0044] The specific printing process is as follows: The prepared composite material 5 is fed directly into the drive device 7 at a constant speed through the filament storage device 6. The motor drives the rotation to feed the composite material into the heating element 8. Under its action, the composite material is heated and melted and extruded by the nozzle 9. Driven by the motion mechanism, the nozzle 9 first melts and deposits the support structure 11 on the printing platform 12 according to the printing strategy. After one layer is deposited, the printing platform descends by a layer thickness distance according to the predetermined increment through the connecting rod 13. Then the nozzle 9 continues to melt and deposit layer by layer according to the printing path and filling path, repeating the above steps until the composite material workpiece 10 is formed.

[0045] The composite workpiece 10 obtained by the FDM molding method is composed of one or more reinforcing materials selected from thermoplastic matrix material, powder, and fiber. The reinforcing material forms a reinforcing region or reinforcing layer structure inside the workpiece, thereby improving at least one of the properties of the workpiece in terms of strength, wear resistance, electrical conductivity, or thermal conductivity.

[0046] This embodiment uses FDM technology, which can realize the integrated molding of workpieces. It has the characteristics of fast molding speed and high design freedom, which can improve the printing quality and molding stability of composite material workpiece 10, thereby effectively broadening the application prospects of this technology.

[0047] This embodiment proposes a method for forming composite materials by wrapping reinforcing materials with thermoplastic sheets and then forming them through spiral winding. This effectively avoids the problems of agglomeration and uneven dispersion that occur during raw material mixing, and fully utilizes the reinforcing effect. During the spiral winding process, the thermoplastic sheet tightly bonds with the reinforcing material through its own curling and wrapping, improving the bonding strength between the reinforcing material and the thermoplastic sheet matrix 2. Furthermore, the thermoplastic sheet has a stable shrinkage rate, and the spiral winding process effectively suppresses the problem of uneven shrinkage of the reinforcing material, reducing the risk of warping, delamination, and peeling of the molded parts. Secondly, it solves the problem of limited reinforcing material filling ratio, allowing for flexible adjustment of the powder or fiber filling ratio according to performance requirements. This method is simple, energy-efficient, and enables continuous production, improving production efficiency. It has a wide range of applications and can prepare composite materials with different properties and uses.

[0048] This embodiment can adjust the type, distribution location, and filling density of reinforcing materials in real time to complete the preparation of the precursor, and combine the printing strategy to complete the printing of composite materials in different areas of the workpiece, so as to meet the needs of personalized customization and functionalization.

[0049] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0050] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0051] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0052] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0053] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

[0054] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this patent should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A method for printing a composite workpiece based on an FDM forming method, characterized in that, The process comprises the following steps: constructing a three-dimensional model of a composite material workpiece (10) to be printed, slicing the three-dimensional model to obtain two-dimensional slice information; determining a printing strategy for the composite material workpiece (10) based on the two-dimensional slice information; filling the reinforcing material into the cladding area of the thermoplastic sheet substrate (2) according to the two-dimensional slice information and the printing strategy, compacting the thermoplastic sheet substrate (2) filled with the reinforcing material, and performing a filament winding cladding molding on the compacted thermoplastic sheet substrate (2) to obtain a composite material (5); setting the printing parameters of the FDM forming equipment based on the printing strategy and the material properties of the composite material (5); controlling the FDM forming equipment to melt and deposit the composite material (5) layer by layer according to the printing strategy and the printing parameters to obtain the composite material workpiece (10).

2. The FDM-based composite workpiece printing method according to claim 1, wherein, The process of obtaining two-dimensional slice information comprises the following steps: obtaining the geometric structure size, surface quality requirement, composite material type information, and composite material distribution information of the composite material workpiece (10) to be printed; designing a three-dimensional model based on the geometric structure size, surface quality requirement, composite material type information, and composite material distribution information; format storage conversion of the three-dimensional model; preprocessing the three-dimensional model after format storage conversion to repair model defects; determining the printing placement orientation of the three-dimensional model according to the surface quality requirement, support structure design, and molding time; slicing the three-dimensional model according to the printing placement orientation to obtain two-dimensional slice information of each two-dimensional contour. 3.The FDM-based composite workpiece printing method of claim 1, wherein, The two-dimensional slice information comprises contour data, size parameters, spatial position information, layer thickness, layer number, support type, filling path, composite material type information, and composite material distribution information corresponding to each two-dimensional slice. 4.The FDM-based composite workpiece printing method of claim 1, wherein, The process of determining the printing strategy of the composite material workpiece (10) comprises the following steps: determining the printing range, printing path, filling strategy, reinforcing material type, and reinforcing material distribution of the composite material workpiece (10) based on the two-dimensional slice information; the printing path adopts a zoning path strategy, which is: applying a bias path in the outer contour area; applying a zigzag reciprocating printing method in the internal filling area; and applying two groups of intersecting straight lines to generate a diamond grid or a square grid in the support area. 5.The FDM-based composite workpiece printing method of claim 1, wherein, The printing strategy includes a segmented material printing method. The process of the segmented material printing method comprises the following steps: converting the material distribution information of the three-dimensional model into multi-type reinforcing material and position distribution data in each area of the composite material workpiece (10); transmitting the position distribution data to the FDM forming equipment; controlling the type and content of the reinforcing material in each area by the FDM forming equipment based on the position distribution data and the printing strategy; corresponding the composite material (5) to the printing path and slice length to perform printing. 6.The FDM-based composite workpiece printing method of claim 1, wherein, The process of filling the reinforcing material into the cladding area of the thermoplastic sheet substrate (2) comprises the following steps: synchronously and continuously conveying two layers of thermoplastic sheet substrates (2) as upper and lower layers; assembling a hopper (1) between the upper and lower layers of thermoplastic sheet substrates (2); feeding the reinforcing material into the space between the upper and lower layers of thermoplastic sheet substrates (2) by the screw quantitative feeding method or the vibration feeding method of the hopper (1); The delivery rate, packing density and discharge area position of the reinforcing material are adjusted to distribute the reinforcing material in the cladding area of the thermoplastic sheet substrate (2). 7.The FDM-based composite workpiece printing method of claim 1, wherein, The process of compacting the thermoplastic sheet substrate (2) filled with the reinforcing material includes: The three-layer composite structure material composed of the upper and lower thermoplastic sheet substrates (2) filled with the reinforcing material and the reinforcing material is delivered to the compacting device (3); The compacting device (3) applies a pressure of 10 MPa to 50 MPa, a vibration frequency of 30 HZ to 100 HZ, and heats the three-layer composite structure material at a temperature of 150 ℃ to 250 ℃. 8.The FDM-based composite workpiece printing method of claim 1, wherein, The process of preparing the composite material (5) includes: The three-layer composite structure material after the compacting treatment is delivered to the spiral winding device (4); The spiral winding device (4) rolls and wraps from both sides to the center of the three-layer composite structure material to cladding the thermoplastic sheet substrate (2) with the reinforcing material; The spiral angle of the spiral winding device (4) is 360°, the rotation rate is 10 r / min to 40 r / min, and the winding tension is 1 N to 3 N. 9.The FDM-based composite workpiece printing method of claim 1, wherein, The process of setting the printing parameters of the FDM forming equipment includes: Adjust the position of the printing platform (12) and preheat at a temperature of 50 ℃ to 110 ℃; set the layer thickness to 0.1 mm to 0.4 mm; the layer height to 0.1 mm to 0.4 mm; the temperature of the nozzle (9) to 180 ℃ to 280 ℃; and the printing speed to 30 mm / s to 80 mm / s. 10.The FDM-based composite workpiece printing method of claim 1, wherein, The process of obtaining the composite material workpiece (10) includes: The composite material (5) is fed into the driving device (7) at a constant speed through the wire storage device (6); The motor in the driving device (7) drives the rotation to feed the composite material (5) to the heating element (8); The heating element (8) heats and melts the composite material (5); The heated and melted composite material (5) is extruded by the nozzle (9); The nozzle (9) melts and deposits a layer of support structure (11) on the printing platform (12); The printing platform (12) is lowered by the layer thickness increment through the connecting rod (13); The nozzle (9) melts and deposits the composite material workpiece (10) layer by layer along the printing path and the filling path.

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