Magnetic fiber reinforced polyether-ether-ketone composite material and additive manufacturing system and method thereof

Abstract

The invention belongs to the technical field of additive manufacturing, and relates to a magnetic fiber reinforced polyether-ether-ketone composite material and an additive manufacturing system and method thereof. The method comprises the following steps: S1, preparing a magnetic fiber reinforced polyether-ether-ketone composite material; s2, based on the magnetic fiber reinforced polyether-ether-ketone composite material, layer-by-layer accumulation printing is carried out through a selective laser sintering technology, so that a magnetic fiber reinforced polyether-ether-ketone composite part is manufactured, and during the period, when the sintering temperature reaches the preheating temperature range, magnetic modified fibers in a sintering molten pool are driven to deflect towards the Z axis through a directional magnetic field, and the magnetic modified fibers in the sintering molten pool are driven to deflect towards the Z axis; the Z-axis mechanical property of the magnetic fiber reinforced polyether-ether-ketone composite part is improved. The prepared magnetic fiber reinforced polyether-ether-ketone composite part is excellent in mechanical property in the Z-axis printing direction.

Description

Technical Field

[0001] This application belongs to the field of additive manufacturing technology, and relates to a magnetic fiber reinforced polyether ether ketone composite material and its additive manufacturing system and method. Background Technology

[0002] Polyetheretherketone (PEEK) is a semi-crystalline aromatic specialty engineering plastic. Due to its excellent mechanical properties, thermal properties, corrosion resistance, flame retardancy, and microwave absorption properties, it is widely used in aerospace, shipbuilding, rail transportation, automotive, and new energy fields. In these strategically important sectors, PEEK components are increasingly trending towards greater complexity, integration, and lightweighting. These components typically have irregular shapes and complex internal structures, making molding increasingly difficult and challenging to meet the requirements of traditional molding methods.

[0003] Selective laser sintering (SLS) technology, as one of the additive manufacturing technologies for engineering applications, has a natural advantage in the integrated molding of complex structures. In recent years, the integrated molding of polyetheretherketone (PEEEK) parts using SLS technology has been gradually applied to various fields. However, due to the layer-by-layer molding process principle of SLS technology and the limitations of the thermodynamic properties of PEEK itself, the mechanical properties of PEEK parts in the Z-axis printing direction are relatively weak (i.e., the mechanical properties in the layer thickness direction are relatively weak), and interlayer delamination may occur, which greatly limits the application of SLS PEEK parts. Therefore, how to improve the mechanical properties of PEEK parts in the Z-axis printing direction has become an urgent problem to be solved. Summary of the Invention

[0004] In response to the deficiencies or improvement needs of existing technologies, this application provides a magnetic fiber reinforced polyetheretherketone composite material and its additive manufacturing system and method, aiming to improve the mechanical properties of polyetheretherketone parts in the Z-axis printing direction.

[0005] This application provides a magnetic fiber reinforced polyetheretherketone composite material, specifically comprising polyetheretherketone powder and magnetically modified fibers.

[0006] As a further preferred embodiment, the mass fraction of magnetically modified fibers in the magnetically reinforced polyether ether ketone composite material is 1-10 wt%.

[0007] The additive manufacturing method for a magnetic fiber reinforced polyetheretherketone composite material provided in the second aspect of this application adopts the following technical solution: An additive manufacturing method for magnetic fiber reinforced polyetheretherketone composite material includes the following steps: S1. Formulate any of the magnetic fiber reinforced polyetheretherketone composite materials described in the first aspect; S2. Based on magnetic fiber reinforced polyether ether ketone composite material, a laser selective sintering process is used for layer-by-layer cumulative printing to obtain magnetic fiber reinforced polyether ether ketone composite parts. During this process, when the sintering temperature reaches the preheating temperature range, a directional magnetic field drives the magnetically modified fibers in the sintering molten pool to deflect towards the Z-axis to improve the Z-axis mechanical properties of the magnetic fiber reinforced polyether ether ketone composite parts.

[0008] As a further preferred embodiment, in step S1, the preparation of the magnetic fiber reinforced polyetheretherketone composite material includes: S11. Heat-treated polyetheretherketone powder, magnetically modified to reinforce fibers to obtain magnetically modified fibers; S12. Mix polyetheretherketone powder and magnetically modified fibers to obtain magnetically reinforced polyetheretherketone composite materials.

[0009] As a further preferred embodiment, in step S11, the magnetic modification treatment of the reinforcing fibers includes: The magnetic nanoparticles were dispersed to obtain a suspension containing the magnetic nanoparticles. Surface oxidation modification treatment is applied to the reinforcing fibers; Based on the suspension, the surface-oxidized reinforced fibers are subjected to fiber magnetization treatment to obtain magnetically modified fibers.

[0010] As a further preferred embodiment, in step S12, the heat-treated polyetheretherketone powder and magnetically modified fibers are mixed, and a high-frequency alternating magnetic field is applied to disrupt the directional arrangement of the fiber magnetic moments.

[0011] As a further preferred embodiment, in step S2, during each layer of printing, when the sintering temperature reaches the preheating temperature range, the time for which the magnetically modified fibers are affected by the directional magnetic field is controlled is as follows: t ,in:

[0012]

[0013] in, The maximum side length of the sintered layer cross section. n The irregularity coefficient of the sintered layer cross section is denoted as . P The perimeter of the cross-sectional shape of the sintered layer. A This represents the area of ​​the cross-sectional shape of the sintered layer.

[0014] The additive manufacturing system provided in the third aspect of this application adopts the following technical solution: An additive manufacturing system for manufacturing magnetic fiber reinforced polyetheretherketone composite parts, comprising: A mixing device is used to provide a high-frequency alternating magnetic field environment and to mix magnetically modified fibers and heat-treated polyetheretherketone powder under the high-frequency alternating magnetic field environment to form a magnetically modified fiber-reinforced polyetheretherketone material. A laser sintering apparatus is used to laser sinter the magnetically modified fiber-reinforced polyetheretherketone (PEEK) material to produce magnetically modified PEEK composite parts, and to generate a directional magnetic field when the sintering temperature reaches the preheating temperature range, causing the magnetically modified fibers in the sintering molten pool to deflect towards the Z-axis.

[0015] As a further preferred embodiment, the laser sintering apparatus includes: The powder spreading unit is used to carry and spread magnetically modified fiber-reinforced polyetheretherketone material to form a powder layer with a preset thickness. A laser scanning sintering unit is located above the powder spreading and forming unit and is used to sinter a preset area of ​​the powder layer, so that the magnetically modified fiber-reinforced polyether ether ketone material is melted and solidified to form a magnetic fiber-reinforced polyether ether ketone composite part. A temperature detection unit is located above the powder spreading and forming unit to detect the temperature of the powder layer in real time. A magnetic field generating unit is arranged around the powder layer to generate a directional magnetic field when the sintering temperature reaches the preheating range.

[0016] The fourth aspect of this application provides a magnetic fiber reinforced polyetheretherketone composite part, which is manufactured using the additive manufacturing method described in the second aspect.

[0017] In summary, compared with the prior art, the technical solutions conceived in this application have the following main technical advantages: 1. This application adds magnetically modified fibers to polyetheretherketone powder. These magnetically modified fibers can improve the mechanical properties of the parts in the Z-axis printing direction when manufacturing magnetically reinforced polyetheretherketone composite parts. The magnetically modified fibers also have good wave absorption properties. This material and the parts made from it have good application prospects in the aerospace and military fields.

[0018] 2. This application can directionally twist the magnetically modified fibers in the molten pool by adding a magnetic field (making them rotate towards the Z-axis), which greatly enhances the mechanical properties of the parts along the Z-axis and solves the problem of insufficient mechanical properties in the Z-direction and easy interlayer separation.

[0019] 3. This application uses a ball mill with an external high-frequency alternating magnetic field to mix polyether ether ketone powder and magnetically modified fibers. Under the combined action of centrifugal force and alternating magnetic field, the adsorption and agglomeration of magnetically modified fibers can be effectively suppressed. Attached Figure Description

[0020] Figure 1This is a flowchart of the main additive manufacturing method provided in the embodiments of this application; Figure 2 This is a detailed flowchart of the additive manufacturing method provided in the embodiments of this application; Figure 3 This is a coordinate system diagram of the square coil provided in the embodiments of this application; Figure 4 This is a schematic diagram of the mixing device provided in the embodiments of this application; Figure 5 This is a schematic diagram of the laser sintering apparatus provided in the embodiments of this application; Figure 6 This is a microstructure diagram of the magnetic fiber reinforced polyetheretherketone composite part provided in the embodiments of this application.

[0021] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1. Mixing device; 1-1. Ball mill jar; 1-2. Magnetic field generating device; 2. Laser sintering device; 2-1. Forming cylinder; 2-2. Powder spreading roller; 2-3. Powder feeding cylinder; 2-4. Laser; 2-5. Galvanometer scanning assembly; 2-6. Thermal imager; 2-7. Second magnetic induction coil; 2-8. Heating tube. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0023] The following is in conjunction with the appendix Figures 1-6 This application will be described in further detail.

[0024] This application discloses an additive manufacturing method. (Refer to...) Figures 1-2 The additive manufacturing method includes the following steps: S1. Prepare magnetic fiber reinforced polyether ether ketone composite material.

[0025] S2. Based on magnetically modified fiber-reinforced polyetheretherketone (PEEK) material, a laser selective sintering process is used for layer-by-layer cumulative printing to produce magnetically reinforced PEEK composite parts. During this process, a directional magnetic field is generated when the sintering temperature reaches the preheating temperature range to drive the magnetically modified fibers in the sintering molten pool to deflect towards the Z-axis (i.e., the layer thickness direction in the printing operation), thereby improving the Z-axis mechanical properties of the magnetically reinforced PEEK composite material.

[0026] In this design, by adding magnetically modified fibers to polyetheretherketone (PEEK) powder, these fibers can act on the magnetically reinforced PEEK composite parts to improve the mechanical properties of the parts in the Z-axis printing direction. Furthermore, by applying a magnetic field to twist the magnetically modified fibers in the molten pool, causing them to deflect towards the Z-axis, the mechanical properties of the parts in the Z-axis are significantly enhanced, solving the problems of insufficient mechanical properties and easy interlayer separation in the Z-axis direction. The resulting parts exhibit excellent mechanical properties and good wave absorption performance, which has promising applications in aerospace and military fields.

[0027] Specifically, in step S1, the preparation of the magnetic fiber reinforced polyetheretherketone composite material includes: S11. Heat-treated polyetheretherketone powder is magnetically modified to reinforce fibers to obtain magnetically modified fibers.

[0028] The heat-treated polyether ether ketone powder includes: screening polyether ether ketone powder with a particle size range of 10-100μm, placing it in an oven for heat treatment, wherein the heat treatment temperature is preferably 280-300℃, and the heat treatment time is preferably 8-12h.

[0029] The process of magnetically modifying fiber materials to obtain magnetically modified fibers includes: dispersing magnetic nanoparticles to obtain a suspension containing magnetic nanoparticles; performing surface oxidation modification on reinforcing fibers; and magnetizing the surface-oxidized reinforcing fibers based on the suspension to obtain magnetically modified fibers.

[0030] Specifically, magnetic nanoparticles with a size of 50-200 nm are dispersed to obtain a suspension containing magnetic nanoparticles, which is then cooled to room temperature for later use. Reinforcing fibers (i.e., fiber-reinforced materials) with a diameter of 5-10 μm and a length of 20-200 μm are screened and subjected to surface oxidation modification treatment. The magnetically modified fibers and an aqueous solution of aniline are added to the suspension, and the magnetically modified fibers are obtained through in-situ polymerization and rinsing and drying processes.

[0031] Preferably, the dispersion treatment of magnetic nanoparticles includes: adding magnetic nanoparticles and deionized water in a beaker at a ratio of 3-10 g: 100 mL, ultrasonically dispersing for 2 h, then stirring for 1 h (stirring speed 200-300 rad / min), then adding oleic acid and SDBS (oleic acid: SDBS: deionized water = 1 g: 1 g: 100 mL), and heating to 80 °C and maintaining the temperature for 2-4 h to obtain a suspension containing magnetic nanoparticles. Here, SDBS refers to sodium dodecylbenzenesulfonate, an anionic surfactant.

[0032] Preferably, the surface oxidation modification treatment of the reinforcing fiber includes: using 40%-80% concentrated nitric acid to perform surface oxidation modification treatment on the reinforcing fiber for a treatment time of 4-8 hours.

[0033] Preferably, the process of magnetizing the surface-oxidized reinforcing fibers based on the suspension to obtain magnetically modified fibers includes: adding the magnetically modified fibers and an aqueous aniline solution to the suspension, and obtaining the magnetically modified fibers through an in-situ polymerization reaction and a rinsing and drying process.

[0034] The process specifically includes: adding the modified reinforcing fiber and a 10% (w / w) aqueous solution of aniline hydrochloride to the above suspension, sonicating at room temperature for 1-3 hours (aqueous solution of aniline hydrochloride: reinforcing fiber: suspension = 5-10 g: 10-20 g: 100 mL) to make it uniformly dispersed, adding 1-butyl-3-methylimidazolium tetrafluoroborate antimagnetic dispersant to avoid agglomeration of the magnetically modified fiber during mixing, then stirring (stirring speed is 200-300 rad / min), adding APS solution dropwise for in-situ polymerization reaction for 8-16 hours, then washing three times with 0.01 mol / L acetone and hydrochloric acid, washing with distilled water until pH is 6.5-7.5, filtering, drying, and preparing the magnetically modified fiber.

[0035] Preferably, the mass fraction of the added 1-butyl-3-methylimidazolium tetrafluoroborate is 0.1-1%, and the addition of this dispersant can suppress the agglomeration of the magnetically modified fibers during the mixing process.

[0036] Preferably, the magnetic nanoparticles include at least one of iron oxide powder, iron-silicon-aluminum powder, and neodymium-iron-boron magnetic powder.

[0037] Preferably, the reinforcing fiber includes at least one of carbon fiber, glass fiber, quartz fiber and basalt fiber.

[0038] S12. Mix polyetheretherketone powder and magnetically modified fibers to obtain magnetically modified fiber-reinforced polyetheretherketone material.

[0039] Specifically, the polyetheretherketone powder after heat treatment in step S11 is mixed with the magnetically modified fibers obtained by magnetic modification using a mechanical mixing method, and a high-frequency alternating magnetic field is applied to disrupt the directional arrangement of the fiber magnetic moments in the composite powder, thereby obtaining a magnetically modified fiber reinforced polyetheretherketone material.

[0040] Preferably, in step S12, a planetary ball mill is used to dry mix the polyetheretherketone powder and the magnetically modified fibers, maintaining a rotation speed of 250-350 rpm / min for 2-4 hours. The magnetically modified fibers account for 1-10 wt% of the mass fraction of the magnetically modified fiber-reinforced polyetheretherketone material. During the mixing process, a high-frequency alternating magnetic field (frequency 1-10 kHz, intensity 50-200 mT) is applied to disrupt the directional alignment of the fiber magnetic moments and suppress the adsorption and agglomeration of the magnetically modified fibers caused by magnetic dipole-dipole interactions.

[0041] Furthermore, in step S2, the preheating temperature of laser selective sintering is 320-330℃, the laser filling scanning power (i.e., filling power) is 5-25W, the filling spacing is 0.2mm, the laser filling scanning rate is 500-5000mm / s, the powder layer thickness is 0.1-0.3mm, the contour power (power used to scan the contour of a two-dimensional graphic) is 3-6W, and the contour scanning rate is 4000mm / s.

[0042] If the filling power is too high (e.g., exceeding 25W), it will cause the polyetheretherketone (PEEK) on the surface of the composite powder (i.e., magnetically modified fiber-reinforced PEEK material) to degrade. If the filling power is too low (e.g., less than 5W), the composite powder will ultimately fail to sinter into shape. Laser selective sintering is an existing technology and will not be discussed in detail here.

[0043] Furthermore, in step S2, the preheating temperature is preferably 380-420℃, and a temperature detection unit (such as a thermal imager) is used to detect the sintering area during the laser selective sintering process. When the temperature is detected to reach the preheating temperature range, the magnetic field generating device starts working and generates a directional magnetic field (the directional magnetic field is generated by magnetic induction coils that are pre-positioned).

[0044] The preheating temperature is preferably 380-420℃ because when the temperature is below 380℃, the melt viscosity is too high, and the magnetically modified fibers cannot move smoothly; forced movement will affect the aggregation of powder particles. When the temperature is above 420℃, polyetheretherketone is prone to aging. The magnetic response time is preferably 5-15s, and the coil current is preferably 5-100A.

[0045] Under this design, as the powder layer is laid layer by layer, the laser selective sintering operation will also have intermittent changes such as "pausing the operation during the powder laying process and starting the sintering operation after the powder laying is completed". This also causes temperature fluctuations throughout the additive manufacturing process, while the magnetic field only occurs when the temperature fluctuates to a relatively high temperature level of 380~420℃, causing the magnetic field to occur intermittently throughout the additive manufacturing process.

[0046] Furthermore, during the printing process, each layer of magnetically modified fibers needs to be subjected to a sufficient magnetic field for a certain period of time, and different magnetic response times are used for different cross-sections of different models to achieve better magnetic fiber deflection effects.

[0047] Specifically, in each layer of printing, when the sintering temperature reaches the preheating temperature range (e.g., 380-420 ℃), the time during which the magnetically modified fibers are affected is t, and the time during which the magnetically modified fibers are affected by the directional magnetic field is... t Its expression is:

[0048] in, The maximum side length of the sintered layer cross-section, in units of mm ; n The irregularity coefficient of the sintered layer cross section is denoted as . n The expression is:

[0049] in, P The perimeter of the cross-sectional shape of the sintered layer. A This represents the area of ​​the cross-sectional shape of the sintered layer.

[0050] Preferably, in step S2, in order to ensure that the magnetically modified fibers of each layer are subjected to sufficient magnetic field influence time during the printing process, after scanning, the laser quickly scans and heats areas with temperatures below 380°C based on data fed back from the thermal imager.

[0051] Furthermore, the distribution of magnetic field strength at different points on the working plane is quantified, and the required current is determined based on the required magnetic field strength, thus establishing a mapping relationship between various process parameters.

[0052] Specifically, taking a square magnetic induction coil as an example, a Cartesian coordinate system is established with the center point of the magnetic field as the origin and the direction perpendicular to the square magnetic induction coil (or other shapes of magnetic induction coils in other embodiments) as the coordinate axis. One side of the coil is parallel to the X-axis of the coordinate system, and the other side is parallel to the Y-axis of the coordinate system. The magnetic field generating device is located at a point on the central plane. x , y ) magnetic field strength B z ( x , y The expression is:

[0053] in, It is the vacuum permeability; I It refers to the magnitude of the current inside the coil; x i ,y i Fixed corresponding to the four sides x Value, fixed y value, d The differential symbol; x ， and y ， Let be the integral variables of the left and right sides and the top and bottom sides of the coil, respectively, with a range of (- ). L / 2, L / 2); L is the side length of the coil.

[0054] Specifically, such as Figure 3 As shown, with side length as L Taking a square coil as an example, the coordinate expression of a point on the left side of the coil is (- L / 2, y ), - L / 2 is the fixed position on the left. x The value, the coordinate expression of a point on the upper part of the coil is ( x , L / 2), L / 2 is the fixed part above. y value.

[0055] Furthermore, additive manufacturing methods also include: S3. After the magnetic fiber reinforced polyetheretherketone composite parts are formed, they are allowed to cool naturally and then annealed to reduce gaps and residual stress in the magnetic fiber reinforced polyetheretherketone composite parts. The annealing temperature is preferably 200-270℃, and the annealing time is preferably 2-4 hours.

[0056] For ease of understanding, the following specific embodiments are provided to further illustrate the technical solutions provided in this application.

[0057] Example 1: S1: Screen polyetheretherketone powder with a particle size range of 10-50 μm and heat-treat it in an oven at 280℃ for 8 hours; add iron oxide powder with a particle size of 50-100 nm and deionized water to a beaker at a ratio of 5 g: 100 mL, ultrasonically disperse for 2 hours, then stir for 1 hour (stirring speed 200 rad / min), then add oleic acid and SDBS (oleic acid: SDBS: deionized water = 1 g: 1 g: 100 mL), heat to 80℃ and hold for 2 hours to form a suspension, then cool to room temperature for later use; perform surface oxidation modification treatment on carbon fiber with 40% concentrated nitric acid for 4 hours; the modified... Carbon fiber material and a 10% (w / w) aqueous solution of aniline hydrochloride were added to the above suspension. The mixture was ultrasonicated at room temperature for 1 hour (aqueous solution of aniline hydrochloride: carbon fiber: suspension = 5 g: 10 g: 100 mL) to ensure uniform dispersion. 0.5 wt% of 1-butyl-3-methylimidazolium tetrafluoroborate antimagnetic dispersant was added to prevent agglomeration of the magnetically modified fibers during mixing. The mixture was then stirred (stirring speed 200 rad / min), and APS solution was added dropwise for in-situ polymerization for 10 hours. After washing three times with 0.01 mol / L acetone and hydrochloric acid, the mixture was washed with distilled water until the pH reached 6.5. The mixture was then filtered, dried, and the magnetically modified fibers were prepared.

[0058] S2: The heat-treated polyetheretherketone powder from step S1 was dry-mixed with the magnetically modified fibers obtained through magnetic modification using a planetary ball mill to obtain magnetically modified fiber-reinforced polyetheretherketone material. The mixing speed was maintained at 350 rpm / min, the mixing time was 4 h, and the magnetically modified fibers accounted for 5 wt% of the composite powder (i.e., the magnetically modified fiber-reinforced polyetheretherketone material). A high-frequency alternating magnetic field with a frequency of 5 kHz and an intensity of 200 mT was applied during the mixing process.

[0059] S3: Based on magnetically modified fiber-reinforced polyetheretherketone (PEEK) material, a three-dimensional magnetic fiber-reinforced PEEK composite part is formed using laser selective sintering (SSC). The preheating temperature is 325℃, the laser filling scanning power is 25W, the filling spacing is 0.2mm, the laser filling scanning rate is 2000mm / s, the powder layer thickness is 0.1mm, the contour power is 6W, the contour scanning rate is 4000mm / s, and the current in the magnetic induction coil is 20A.

[0060] S4: After molding, the magnetic fiber reinforced polyether ether ketone composite parts are naturally cooled down and then annealed at a temperature of 270℃ for 2 hours.

[0061] Example 2: S1: Screen polyetheretherketone powder with a particle size range of 10-50 μm and heat-treat it in an oven at 280℃ for 8 hours; add neodymium iron boron magnetic powder with a particle size of 50-100 nm and deionized water in a beaker at a ratio of 10 g: 100 mL, ultrasonically disperse for 2 hours, then stir for 1 hour (stirring speed 300 rad / min), then add oleic acid and SDBS (oleic acid: SDBS: deionized water = 1 g: 1 g: 100 mL), heat to 80℃ and hold for 2 hours to form a suspension, then cool to room temperature for later use; perform surface oxidation modification treatment on glass fiber with 50% concentrated nitric acid for 6 hours; the modified... The glass fiber material and a 10% (w / w) aqueous solution of aniline hydrochloride were added to the above suspension. The mixture was ultrasonicated at room temperature for 1 hour (aqueous solution of aniline hydrochloride: glass fiber: suspension = 6 g: 10 g: 100 mL) to ensure uniform dispersion. 1 wt% of 1-butyl-3-methylimidazolium tetrafluoroborate antimagnetic dispersant was added to prevent agglomeration of the magnetically modified fibers during mixing. The mixture was then stirred (stirring speed 200 rad / min), and APS solution was added dropwise for in-situ polymerization for 16 hours. After washing three times with 0.01 mol / L acetone and hydrochloric acid, the mixture was washed with distilled water until the pH reached 7. The mixture was then filtered, dried, and the magnetically modified fibers were prepared.

[0062] S2: The heat-treated polyetheretherketone powder from step S1 was dry-mixed with the magnetically modified fibers obtained through magnetic modification using a planetary ball mill to obtain magnetically modified fiber-reinforced polyetheretherketone material. The mixing speed was maintained at 300 rpm / min, the mixing time was 4 h, and the magnetically modified fibers accounted for 10 wt% of the composite powder (i.e., the magnetically modified fiber-reinforced polyetheretherketone material). A high-frequency alternating magnetic field with a frequency of 5 kHz and an intensity of 150 mT was applied during the mixing process.

[0063] S3: Based on magnetically modified fiber-reinforced polyetheretherketone (PEEK) material, magnetic fiber-reinforced PEEK composite parts are formed using laser selective sintering (SSC) process. The preheating temperature is 329℃, the laser filling scanning power is 21W, the filling spacing is 0.2mm, the laser filling scanning rate is 2000mm / s, the powder layer thickness is 0.1mm, the contour power is 3W, the contour scanning rate is 4000mm / s, and the current in the magnetic induction coil is 50A.

[0064] S4: After molding, the magnetic fiber reinforced polyether ether ketone composite parts are naturally cooled down and then annealed at 250℃ for 2 hours.

[0065] Example 3: S1: Screen polyetheretherketone powder with a particle size range of 10-50 μm and heat-treat it in an oven at 290℃ for 10 h; add iron-silicon-aluminum powder with a particle size of 50-100 nm and deionized water in a beaker at a ratio of 10 g: 100 mL and ultrasonically disperse for 2 h, then stir for 1 h (stirring speed 300 rad / min), then add oleic acid and SDBS (oleic acid: SDBS: deionized water = 1 g: 1 g: 100 mL), heat to 80℃ and hold for 2 h to form a suspension, then cool to room temperature for later use; perform surface oxidation modification treatment on quartz fibers with 80% concentrated nitric acid for 8 h; and then modify... The treated quartz fiber material and a 10% (w / w) aqueous solution of aniline hydrochloride were added to the above suspension. The mixture was sonicated at room temperature for 1 hour (aqueous solution of aniline hydrochloride: quartz fiber: suspension = 6 g: 10 g: 100 mL) to ensure uniform dispersion. 1 wt% of 1-butyl-3-methylimidazolium tetrafluoroborate antimagnetic dispersant was added to prevent agglomeration of the magnetically modified fibers during mixing. The mixture was then stirred (stirring speed 200 rad / min), and APS solution was added dropwise for in-situ polymerization for 12 hours. After washing three times with 0.01 mol / L acetone and hydrochloric acid, the mixture was washed with distilled water until the pH reached 7. The mixture was then filtered, dried, and the magnetically modified fibers were prepared.

[0066] S2: The heat-treated polyetheretherketone (PEEK) powder from S1 was dry-mixed with the magnetically modified fibers obtained through magnetic modification using a planetary ball mill to obtain magnetically modified fiber-reinforced PEEK material. The mixing speed was maintained at 320 rpm / min, and the mixing time was 3.5 h. The magnetically modified fibers accounted for 10 wt% of the composite powder (i.e., the magnetically modified fiber-reinforced PEEK material). A high-frequency alternating magnetic field with a frequency of 5 kHz and an intensity of 150 mT was applied during the mixing process.

[0067] S3: Based on magnetically modified fiber-reinforced polyetheretherketone (PEEK) material, a three-dimensional magnetic fiber-reinforced PEEK composite part is formed using a laser selective sintering process. The preheating temperature is 326℃, the laser filling scanning power is 25W, the filling spacing is 0.2mm, the laser filling scanning rate is 2000mm / s, the powder layer thickness is 0.1mm, the contour power is 6W, the contour scanning rate is 4000mm / s, and the current in the magnetic induction coil is 60A.

[0068] S4: After molding, the magnetic fiber reinforced polyether ether ketone composite parts are naturally cooled down and then annealed at a temperature of 270℃ for 4 hours.

[0069] Example 4: S1: Screen polyetheretherketone powder with a particle size range of 10-100μm and heat-treat it in an oven at 290℃ for 9h; add iron-cobalt-nickel powder with a particle size of 50-100nm and deionized water in a beaker at a ratio of 10g:100mL and ultrasonically disperse for 2h, then stir for 1h (stirring speed 250rad / min), then add oleic acid and SDBS (oleic acid:SDBS:deionized water = 1g:1g:100mL), heat to 80℃ and hold for 2h to form a suspension, then cool to room temperature for later use; perform surface oxidation modification treatment on quartz fibers with 50% concentrated nitric acid for 6h; the modified... The quartz fiber material and a 10% (w / w) aqueous solution of aniline hydrochloride were added to the above suspension. The mixture was ultrasonicated at room temperature for 1 hour (aqueous solution of aniline hydrochloride: quartz fiber: suspension = 8 g: 15 g: 100 mL) to ensure uniform dispersion. 0.3 wt% of 1-butyl-3-methylimidazolium tetrafluoroborate antimagnetic dispersant was added to prevent agglomeration of the magnetically modified fibers during mixing. The mixture was then stirred (stirring speed 200 rad / min), and APS solution was added dropwise for in-situ polymerization for 16 hours. After washing three times with 0.01 mol / L acetone and hydrochloric acid, the mixture was washed with distilled water until the pH reached 7. The mixture was then filtered, dried, and the magnetically modified fibers were prepared.

[0070] S2: The heat-treated polyetheretherketone (PEEK) powder from S1 was dry-mixed with the magnetically modified fibers obtained through magnetic modification using a planetary ball mill to obtain magnetically modified fiber-reinforced PEEK material. The mixing speed was maintained at 300 rpm / min, and the mixing time was 4 hours. The magnetically modified fibers accounted for 6 wt% of the composite powder (i.e., the magnetically modified fiber-reinforced PEEK material). A high-frequency alternating magnetic field with a frequency of 2 kHz and an intensity of 50 mT was applied during the mixing process.

[0071] S3: Based on magnetically modified fiber-reinforced polyetheretherketone (PEEK) material, a three-dimensional magnetic fiber-reinforced PEEK composite part is formed using a laser selective sintering process. The preheating temperature is 326℃, the laser filling scanning power is 25W, the filling spacing is 0.2mm, the laser filling scanning rate is 2000mm / s, the powder layer thickness is 0.1mm, the contour power is 6W, the contour scanning rate is 4000mm / s, and the current in the magnetic induction coil is 50A.

[0072] S4: After molding, the magnetic fiber reinforced polyether ether ketone composite parts are naturally cooled down and then annealed at 250℃ for 4 hours.

[0073] Example 5: S1: Screen polyetheretherketone powder with a particle size range of 10-100μm and heat-treat it in an oven at 280℃ for 8 hours; add iron oxide powder with a particle size of 50-100nm and deionized water to a beaker at a ratio of 10g:100mL and ultrasonically disperse for 2 hours, then stir for 1 hour (stirring speed 300rad / min), then add oleic acid and SDBS (oleic acid:SDBS:deionized water = 1g:1g:100mL), heat to 80℃ and hold for 4 hours to form a suspension, then cool to room temperature for later use; perform surface oxidation modification treatment on glass fiber with 80% concentrated nitric acid for 6 hours; The treated glass fiber material and a 10% (w / w) aqueous solution of aniline hydrochloride were added to the above suspension. The mixture was ultrasonicated at room temperature for 1 hour (aqueous solution of aniline hydrochloride: glass fiber: suspension = 5 g: 10 g: 100 mL) to ensure uniform dispersion. 1 wt% of 1-butyl-3-methylimidazolium tetrafluoroborate antimagnetic dispersant was added to prevent agglomeration of the magnetically modified fibers during mixing. The mixture was then stirred (stirring speed 200 rad / min), and APS solution was added dropwise for in-situ polymerization for 12 hours. After washing three times with 0.01 mol / L acetone and hydrochloric acid, the mixture was washed with distilled water until the pH reached 7. The mixture was then filtered, dried, and the magnetically modified fibers were prepared.

[0074] S2: The polyetheretherketone powder after heat treatment in step S1 is dry-mixed with the magnetically modified fibers obtained through magnetic modification using a planetary ball mill to obtain a magnetically modified fiber-reinforced polyetheretherketone material. The mixing speed is maintained at 350 rpm / min, the mixing time is 4 h, and the magnetically modified fibers account for 10 wt% of the composite powder (i.e., the magnetically modified fiber-reinforced polyetheretherketone material). A high-frequency alternating magnetic field with a frequency of 10 kHz and an intensity of 150 mT is applied during the mixing process.

[0075] S3: Based on magnetically modified fiber-reinforced polyetheretherketone (PEEK) material, a three-dimensional magnetic fiber-reinforced PEEK composite part is formed using a laser selective sintering process. The preheating temperature is 325℃, the laser filling scanning power is 23W, the filling spacing is 0.2mm, the laser filling scanning rate is 2000mm / s, the powder layer thickness is 0.1mm, the contour power is 6W, the contour scanning rate is 4000mm / s, and the current in the magnetic induction coil is 60A.

[0076] S4: After molding, the magnetic fiber reinforced polyether ether ketone composite parts are naturally cooled down and then annealed at a temperature of 260℃ for 4 hours.

[0077] This application also discloses an additive manufacturing system. (Refer to...) Figures 4-6The additive manufacturing system includes a mixing device 1 and a laser sintering device 2. The mixing device 1 is used to provide a high-frequency alternating magnetic field environment and to mix magnetically modified fibers and heat-treated polyetheretherketone powder under the high-frequency alternating magnetic field environment to prepare magnetically modified fiber-reinforced polyetheretherketone material. The laser sintering device 2 is used to laser sinter the magnetically modified fiber-reinforced polyetheretherketone material to produce magnetically reinforced polyetheretherketone composite parts, and to generate a directional magnetic field when the sintering temperature reaches the preheating temperature range, causing the magnetically modified fibers in the sintering molten pool to deflect towards the Z-axis.

[0078] Among them, such as Figure 4 As shown, the mixing device 1 preferably includes a planetary ball mill. A magnetic field generating device 1-2 is installed in the slots of the four grinding jars 1-1 of the planetary ball mill. The magnetic field generating device 1-2 is used to generate a high-frequency alternating magnetic field during the ball milling process. Preferably, the magnetic field generating device 1-2 includes a first magnetic induction coil, which is preferably made of nickel-zinc ferrite and is externally connected to an AC power supply via a frequency converter.

[0079] Among them, such as Figure 5 As shown, the laser sintering device 2 is mainly based on high-temperature laser selective sintering equipment. Preferably, a magnetic field generating device is added to the equipment to provide a controllable online magnetic field, and a thermal imager 2-6 is additionally installed to monitor the temperature of the scanning area, thereby controlling the switching and intensity of the magnetic field generating device 1-2. The magnetic field generating device 1-2 includes a coil, preferably made of nickel-iron alloy. To facilitate magnetic field realization and parameter control, the magnetic field generating device 1-2 can employ a dynamic alternating electromagnetic device.

[0080] Furthermore, in some specific embodiments, the laser sintering apparatus 2 includes a powder spreading and forming unit, a laser scanning sintering unit, a temperature detection unit, and a magnetic field generating unit. The powder spreading and forming unit is used to carry and spread the magnetically modified fiber-reinforced polyetheretherketone (PEEK) material to form a powder layer with a preset thickness. The laser scanning sintering unit is positioned above the powder spreading and forming unit and is used to sinter a preset area of ​​the final layer, causing the magnetically modified fiber-reinforced PEEK material to melt and solidify to obtain a magnetic fiber-reinforced PEEK composite part. The temperature detection unit is positioned above the powder spreading and forming unit and is used to detect the temperature of the powder layer in real time. The magnetic field generating unit is arranged around the powder layer and is used to generate a directional magnetic field when the sintering temperature reaches the preheating range.

[0081] Preferred, such as Figure 5 As shown, the powder spreading and forming unit includes a forming cylinder 2-1, a powder spreading roller 2-2, and a powder feeding device. The cylinder bodies of the powder feeding cylinder 2-3 and the forming cylinder 2-1 are made of materials such as silicon carbide or alumina.

[0082] The forming cylinder 2-1 is used to support the magnetically modified fiber-reinforced polyetheretherketone (PEEK) material. Generally, the forming cylinder 2-1 is equipped with an adjustable support platform. The magnetically modified fiber-reinforced PEEK material is laid on the support platform.

[0083] The powder spreading roller 2-2 is laterally positioned above the forming cylinder 2-1 to evenly spread the magnetically modified fiber-reinforced polyetheretherketone (PEEK) material onto the surface of the forming cylinder 2-1 to form a powder layer. Generally, the lateral movement of the powder spreading roller 2-2 is driven by a power source such as a motor, pneumatic cylinder, or hydraulic cylinder; even more specifically, multiple motors and mechanical transmission structures can be combined to form a multi-degree-of-freedom motion mechanism to drive the lateral movement and rotation of the powder spreading roller 2-2, ensuring the smooth and uniform spreading of the magnetically modified fiber-reinforced PEEK material.

[0084] The powder feeding device is used to convey magnetically modified fiber-reinforced polyetheretherketone (PEEK) material to the forming cylinder 2-1. The powder feeding device preferably includes a powder feeding cylinder 2-3, which may also have a powder spreading roller 2-2 on its upper part for spreading and pushing the powder. Generally, the powder feeding cylinder 2-3 uses a conveyor belt, pusher plate, or other mechanism to convey the powder, such as a belt conveyor or auger conveyor.

[0085] Preferably, the laser scanning sintering unit includes a laser 2-4 and a galvanometer scanning assembly 2-5. The laser 2-4 outputs a laser beam, and the galvanometer scanning assembly 2-5 deflects and conducts the laser beam, rapidly deflecting it via built-in optical devices such as a reflector to scan the sintering area along a preset path. The galvanometer scanning assembly 2-5 is prior art and will not be described in detail here.

[0086] The temperature detection unit is preferably a thermal imager 2-6, which is positioned above the powder spreading and forming unit to detect the temperature of the powder layer in real time.

[0087] Preferably, the magnetic field generating unit includes a second magnetic induction coil 2-7, which is arranged circumferentially around the forming cylinder 2-1 to generate a directional magnetic field. Generally, the magnetic field generating unit is used to intermittently operate based on feedback data from the thermal imager 2-6 to generate a directional magnetic field distributed along the Z-axis of the printing direction, causing the magnetically modified fibers in the molten pool to deflect towards the Z-axis. For ease of understanding, Figure 6 (a) shows the approximate distribution of the magnetically modified fibers before the application of a directional magnetic field. Figure 6 (b) shows the approximate distribution of the magnetically modified fibers after the application of a directional magnetic field.

[0088] Furthermore, the laser sintering apparatus 2 also includes a preheating unit and a controller. The preheating unit is used to preheat the powder and maintain the cylinder temperature of the forming cylinder 2-1. Preferably, the preheating unit includes heating tubes 2-8. Preferably, the heating tubes 2-8 are mounted above the forming cylinder 2-1 to heat the powder layer in the forming cylinder 2-1. The heating tubes 2-8 are preferably arranged in a circular pattern. More preferably, in some embodiments, the preheating unit also includes a drive mechanism for adjusting the height of the heating tubes 2-8. The drive mechanism is prior art and will not be described in detail here.

[0089] Furthermore, the controller is electrically connected to the laser scanning sintering unit, powder spreading and forming unit, temperature detection unit, and magnetic field generating unit, and is used to control the operation of each unit. The control principle of the controller is existing technology and will not be elaborated on here.

[0090] In actual use of the laser sintering device 2, the powder spreading and forming unit spreads powder onto the surface of the forming cylinder 2-1 through the powder supply cylinder to form a thin layer (the thickness is set according to process requirements). Under the control of the controller, the laser scanning sintering unit scans the target area according to the slice data. After the powder absorbs the laser energy, it melts or softens locally, forming a dense sintered layer.

[0091] Then, the powder-spreading forming unit re-spreads the material, and the laser scanning sintering unit continues to sinter the new layer, which is naturally supported and combined with the already formed part by the unsintered powder. This process is repeated to obtain the final product, resulting in a magnetic fiber reinforced polyether ether ketone composite part.

[0092] When necessary, the magnetic fiber reinforced polyether ether ketone composite parts are cooled to room temperature and annealed to reduce gaps and residual stress in the magnetic fiber reinforced polyether ether ketone composite parts and avoid deformation caused by residual stress. Then, the unsintered powder is removed, and if necessary, post-treatments such as impregnation, sintering or metal infiltration are performed to improve the strength of the magnetic fiber reinforced polyether ether ketone composite parts and achieve powder removal and cleaning.

[0093] This application also discloses a magnetic fiber reinforced polyetheretherketone (PEEK) composite material, which comprises PEEK powder and magnetically modified fibers. The mass fraction of the magnetically modified fibers in the magnetic fiber reinforced PEEK composite material is 1-10 wt%.

[0094] This application also discloses a magnetic fiber reinforced polyetheretherketone composite part, which is manufactured by the above-described additive manufacturing method or by the above-described additive manufacturing system.

[0095] It should be understood that expressions such as "comprising" and "may include" as used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "comprising" and / or "having" may be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or combination thereof, but should not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0096] It should be understood that the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0097] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0098] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0099] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A magnetic fiber reinforced polyetheretherketone composite material, characterized in that, Including polyetheretherketone powder and magnetically modified fibers.

2. The magnetic fiber reinforced polyetheretherketone composite material as described in claim 1, characterized in that, The mass fraction of magnetically modified fibers in the magnetically reinforced polyetheretherketone composite material is 1-10 wt%.

3. An additive manufacturing method for manufacturing magnetic fiber reinforced polyetheretherketone composite parts, characterized in that, Includes the following steps: S1. Formulate the magnetic fiber reinforced polyetheretherketone composite material as described in any one of claims 1-2; S2. Based on magnetic fiber reinforced polyether ether ketone composite material, a laser selective sintering process is used for layer-by-layer printing to obtain magnetic fiber reinforced polyether ether ketone composite parts. During this process, when the sintering temperature reaches the preheating temperature range, the magnetically modified fibers in the sintering molten pool are driven by a directional magnetic field to deflect towards the Z-axis, thereby improving the Z-axis mechanical properties of the magnetic fiber reinforced polyether ether ketone composite parts.

4. The additive manufacturing method as described in claim 3, characterized in that, In step S1, the preparation of the magnetic fiber reinforced polyetheretherketone composite material includes: S11. Heat-treated polyetheretherketone powder, magnetically modified to reinforce fibers to obtain magnetically modified fibers; S12. Mix polyetheretherketone powder and magnetically modified fibers to obtain magnetically reinforced polyetheretherketone composite materials.

5. The additive manufacturing method as described in claim 4, characterized in that, In step S11, the magnetic modification treatment of the reinforcing fibers includes: The magnetic nanoparticles were dispersed to obtain a suspension containing the magnetic nanoparticles. Surface oxidation modification treatment is applied to the reinforcing fibers; Based on the suspension, the surface-oxidized reinforced fibers are subjected to fiber magnetization treatment to obtain magnetically modified fibers.

6. The additive manufacturing method as described in claim 4, characterized in that, In step S12, the heat-treated polyetheretherketone powder and magnetically modified fibers are mixed, and a high-frequency alternating magnetic field is applied to disrupt the directional arrangement of the fiber magnetic moments.

7. The additive manufacturing method according to any one of claims 3-6, characterized in that, In step S2, during each layer of printing, when the sintering temperature reaches the preheating temperature range, the time for the magnetically modified fibers to be affected by the directional magnetic field is controlled as follows: t ,in: in, The maximum side length of the sintered layer cross section. n The irregularity coefficient of the sintered layer cross section is denoted as . P The perimeter of the cross-sectional shape of the sintered layer. A This represents the area of ​​the cross-sectional shape of the sintered layer.

8. An additive manufacturing system for manufacturing magnetic fiber reinforced polyetheretherketone composite parts using the additive manufacturing method as described in any one of claims 3-7, characterized in that, include: A mixing device (1) is used to provide a high-frequency alternating magnetic field environment and to mix magnetically modified fibers and heat-treated polyether ether ketone powder in a high-frequency alternating magnetic field environment to form a magnetically modified fiber-reinforced polyether ether ketone material. Laser sintering device (2) is used for laser sintering of the magnetically modified fiber-reinforced polyether ether ketone material to obtain magnetically modified fiber-reinforced polyether ether ketone composite parts, and is used to generate a directional magnetic field when the sintering temperature reaches the preheating temperature range, so that the magnetically modified fibers in the sintering molten pool deflect towards the Z-axis.

9. The additive manufacturing system as described in claim 8, characterized in that, The laser sintering apparatus (2) includes: The powder spreading unit is used to carry and spread magnetically modified fiber-reinforced polyetheretherketone material to form a powder layer with a preset thickness. A laser scanning sintering unit is located above the powder spreading and forming unit and is used to sinter a preset area of ​​the powder layer, so that the magnetically modified fiber-reinforced polyether ether ketone material is melted and solidified to form a magnetic fiber-reinforced polyether ether ketone composite part. A temperature detection unit is located above the powder spreading and forming unit to detect the temperature of the powder layer in real time. A magnetic field generating unit is arranged around the powder layer to generate a directional magnetic field when the sintering temperature reaches the preheating range.

10. A magnetic fiber reinforced polyetheretherketone composite part, characterized in that, It is manufactured using the additive manufacturing method as described in any one of claims 3-7.

Images