Gradient functional material BJ printing device and method based on array nozzles

Abstract

The invention discloses a gradient functional material BJ printing device and method based on array nozzles. Comprising a printing base plate which is vertically and movably arranged, three independent powder feeding spray heads, a binder spray head, a binder storage tank, a spray head fixing disc, a high-speed camera used for synchronously capturing the bonding condition of a binder and powder, a horizontal sliding rail, a water balance beam and a leveling roller used for leveling the set powder. Wherein the three powder feeding spray heads and the binder spray head are fixedly arranged on a spray head fixing disc which is horizontally and movably arranged, and the high-speed camera is arranged on the lower surface of the spray head fixing disc and right faces a printing substrate. Ceramic / ceramic, ceramic / metal, metal / metal and other gradient functional materials are prepared through array multi-nozzle coaxial powder feeding and binder spraying by adopting a binder spraying-powder conveying method.

Description

Technical Field

[0001] The present invention relates to a technology in the field of composite materials, specifically a binder jetting (BJ) printing device and method for functionally graded materials based on an array of nozzles. Background Art

[0002] Functionally Graded Materials (FGM) have unique properties and are widely used in industries such as aerospace, medicine, electro-optics, and energy. The traditional preparation methods of functionally graded materials mainly include chemical vapor deposition, physical vapor deposition, powder metallurgy, self-propagating high-temperature synthesis, centrifugal casting, electrodeposition, and plasma spraying. However, these traditional preparation methods usually have high costs, long cycles, complex processes, and it is difficult to prepare parts with complex shapes and high forming accuracies. Summary of the Invention

[0003] Aiming at the problems of complex processes, long cycles, and poor material versatility in the existing additive preparation of functionally graded materials, as well as the deficiency that the existing multi-nozzle preparation technology cannot print multi-component functionally graded materials, the present invention proposes a BJ printing device and method for functionally graded materials based on an array of nozzles; and by coaxially feeding powder and jetting binder with an array of multi-nozzles, functionally graded materials such as ceramic / ceramic, ceramic / metal, and metal / metal are prepared by the method of jetting binder - conveying powder.

[0004] The present invention is realized by the following technical solutions:

[0005] The present invention relates to a binder jetting printing device for functionally graded materials based on an array of nozzles, including: a printing substrate vertically movably arranged, three independent powder feeding nozzles, a binder nozzle, a binder storage tank, a nozzle fixing plate, a high-speed camera for synchronously capturing the bonding situation of the binder and the powder, a horizontal slide rail, a horizontal balance beam, and a leveling roller for leveling the settled powder, wherein: the three powder feeding nozzles and the binder nozzle are respectively fixedly arranged on the horizontally movably arranged nozzle fixing plate, and the high-speed camera is arranged on the lower surface of the nozzle fixing plate and is directly opposite to the printing substrate.

[0006] Technical Effects

[0007] The present invention transforms the traditional BJ printer device of powder bed powder spreading - binder jetting into a new device with an array of multi - nozzles for coaxial powder feeding and binder jetting: several nozzles are designed to respectively convey powders of different materials and jet binders, and the nozzles for conveying powders of different materials and the nozzles for jetting binders are fixed on the same disc. The disc can achieve precise movement of the nozzles in the X - Y plane through a horizontal slide rail, a horizontal cross - beam, and a motion control system; the fixed disc can rotate in the X - Y plane through a motor control system, enabling coaxial switching between the binder nozzle and different powder nozzles. The printing substrate descends one layer every time one layer is printed through a lifting rod and a motor control system. Meanwhile, the printing process is designed as a new method of binder jetting - powder conveying: the binder nozzle first jets the binder onto the printing substrate according to the pattern designed by CAD, and then the powder nozzle precisely conveys the powder to the already jetted binder pattern through coaxial powder feeding, thereby realizing the fixation of the powder, reducing powder dusting, and the disturbance after powder falling. The powder is conveyed in an air - borne manner, and the conveying pipeline is equipped with a piezoelectric switching valve and a powder feeding flow rate detection device: the powder feeding flow rate detection device can detect the conveying amount of the air - powder particle flow in real - time through a diode laser and a photodiode; the piezoelectric switching valve realizes the opening and closing of the air - powder particle flow through a pulsed voltage, a piezoelectric ceramic, and an elastomer. At the same time, a high - speed camera is mounted to capture the real - time combination situation of the binder and the powder, and adjustments can be made in a timely manner when problems occur. Description of the Drawings

[0008] Figure 1 Schematic diagram of the BJ printer equipped with an array of multi - nozzles according to the present invention;

[0009] Figure 2 Fixed disc for coaxial precise powder feeding and binder jetting (can move and rotate in the X - Y plane);

[0010] Figure 3 Powder feeding flow rate detection device;

[0011] Figure 4 Piezoelectric switching valve for controlling the air - powder particle flow;

[0012] In the figure: horizontal cross - beam 1, first horizontal slide rail 2, second horizontal slide rail 3, binder storage tank 4, nozzle fixed disc 5, binder nozzle 6, leveling roller 7, first powder feeding nozzle 8, second powder feeding nozzle 9, third powder feeding nozzle 10, high - speed camera 11, printing substrate 12, lifting rod 13, slide rail connecting rod 14, diode laser 15, photodiode 16, powder conveying pipe 17, piezoelectric ceramic stack 18, driving wire inlet / outlet hole 19, adjusting screw hole 20, end cover 21, housing 22, elastomer 23. Detailed Description of the Invention

[0013] As Figures 1 - 4As shown in the figure, this embodiment relates to a binder jetting forming and printing device for gradient functional materials based on an array of nozzles, including: a vertically movable printing substrate 12, three independent powder feeding nozzles 8, 9, 10, a binder nozzle 6, a binder storage tank 4, a nozzle fixing plate 5, a high-speed camera 11 for synchronously capturing the combination of the binder and the powder, horizontal slide rails 2, 3, a horizontal balance beam 1, and a leveling roller 7 for leveling the settled powder. Among them: the three powder feeding nozzles 8, 9, 10 and the binder nozzle 6 are respectively fixedly arranged on the horizontally movable nozzle fixing plate 5, and the high-speed camera 11 is arranged on the lower surface of the nozzle fixing plate 5 and is directly opposite to the printing substrate 12.

[0014] The so-called horizontally movable setting means that: the nozzle fixing plate 5 is arranged on the horizontal cross beam 1 through a slide rail connecting rod 14, and the horizontal balance beam 1 is arranged on the horizontal slide rails 2, 3 so as to achieve precise movement and rotation in the X-Y plane.

[0015] The so-called vertically movable setting means that: the printing substrate 12 can achieve lifting movement in the Z-axis direction through the connected lifting rod, and after each layer is printed, the substrate descends by one layer.

[0016] The three powder feeding nozzles 8, 9, 10 are respectively connected to the corresponding powder supply bins through their respective corresponding powder conveying pipes 17, and are equipped with servo motors, piezoelectric switching valves, and powder feeding flow detection devices.

[0017] The so-called array of nozzles means that: the nozzles for conveying powder can be 2, 3 or several, and the nozzle for jetting the binder is 1.

[0018] The high-speed camera has a shooting speed exceeding 100 frames per second and a resolution not lower than 1024×1024. It is fixed on the nozzle fixing plate together with the binder and powder nozzles to synchronously capture the combination of the binder and the powder, and in case of problems, it will feedback to the system in time for adjustment.

[0019] As Figure 2 As shown in the figure, the powder nozzles and the binder nozzle of different materials are fixed on a disc, and the disc drives the nozzles to achieve precise movement and rotation in the X-Y plane, so as to realize coaxial precise powder feeding and jetting of the binder. Compared with the traditional printing method of powder bed laying - jetting binder, this device fundamentally solves the problem of powder cleaning after the green body printing is completed.

[0020] After the binder nozzle jets the binder onto the printing substrate according to the computer-aided design graphics, the powder nozzles precisely convey the corresponding powder to the already jetted binder through coaxial movement to fix the powder, reduce powder dusting, and the disturbance after powder falling.

[0021] As Figure 3As shown, a powder flow detection device is provided in the powder delivery pipe 17. The powder flow detection device includes a diode laser 15 and a photodiode 16 which are oppositely arranged. Specifically: the laser beam emitted by the diode laser passes horizontally through the gas-powder particle flow in the powder delivery pipe and is received by the photodiode; when the powder delivery flow fluctuates, the diffusion, absorption, and reflection of the laser by the gas-powder particle flow will change, resulting in a change in the laser energy received by the photodiode, and its output voltage also changes accordingly; by using the quantitative relationship between the output voltage and the powder delivery flow, real-time detection of the gas-powder particle flow rate can be achieved.

[0022] As Figure 4 shown, a piezoelectric switch valve is provided in the powder delivery pipe 17. The piezoelectric switch valve includes: a housing 22 and a piezoelectric ceramic stack 18, an elastic body 23, an adjusting screw hole 20, and an end cap 21 arranged therein. As Figure 4 (b) shown, under the action of a pulsed voltage signal, the piezoelectric ceramic stack in the valve elongates downward against the resistance of the elastic body below, forcing the elastic body to close the valve port; as Figure 4 (a) shown, after the pulsed signal is removed, the piezoelectric ceramic stack shortens, the elastic body resets, and the valve port opens.

[0023] This embodiment relates to a method for preparing a ceramic / ceramic / ceramic integrated ceramic shell and ceramic core based on the above-mentioned BJ printer equipped with an array of multi-nozzles, including:

[0024] 1) After designing the model of the ceramic / ceramic / ceramic integrated ceramic shell and ceramic core through auxiliary software and performing slicing processing, the obtained sliced model is imported into a BJ printer equipped with an array of multi-nozzles.

[0025] 2) Configure the raw and auxiliary materials, including: binders (epoxy resin, furan resin) and ceramic powders of different materials (corundum powder, zircon powder, mullite powder, quartz powder, yttrium oxide powder). Specifically: the ceramic shell consists of a dense surface layer and a porous back layer, and usually the materials of the surface layer and the back layer are also different; therefore, three kinds of ceramic powders need to be prepared.

[0026] The binder mentioned above can be an organic binder or an inorganic binder, depending on the powder to be printed.

[0027] The different material powders mentioned refer to ceramic / ceramic, ceramic / metal, and metal / metal.

[0028] 3) After setting the printing parameters and performing printing, the obtained green body is subjected to impregnation strengthening and roasting treatments.

[0029] The above specific embodiments can be locally adjusted in different ways by those skilled in the art without departing from the principles and purposes of the present invention. The protection scope of the present invention is subject to the claims and is not limited by the above specific embodiments. All implementation solutions within its scope are subject to the present invention.

Claims

1. A gradient functional material BJ printing device based on an array nozzle, characterized in that Including: A vertically movable printing substrate, three independent powder feeding nozzles, a binder nozzle, a binder storage tank, a nozzle fixing disk, a high-speed camera for synchronously capturing the combination of the binder and the powder, a horizontal slide rail, a horizontal balance beam, and a leveling roller for leveling the settled powder. Among them: the three powder feeding nozzles and the binder nozzle are respectively fixedly arranged on the horizontally movable nozzle fixing disk, and the high-speed camera is arranged on the lower surface of the nozzle fixing disk and is directly opposite to the printing substrate.

2. The gradient functional material BJ printing device based on an array nozzle according to claim 1, wherein The so-called horizontally movable setting means that: the nozzle fixing disk is arranged on the horizontal cross beam through a slide rail connecting rod, and the horizontal balance beam is arranged on the horizontal slide rail to achieve precise movement and rotation in the X-Y plane.

3. The gradient functional material BJ printing device based on an array nozzle according to claim 1, characterized in that, The so-called vertically movable setting means that: the printing substrate can achieve lifting movement in the Z-axis direction through the connected lifting rod, and after each layer is printed, the substrate descends one layer.

4. The gradient functional material BJ printing device based on an array nozzle according to claim 1, characterized in that, The three powder feeding nozzles are respectively connected to the corresponding powder supply bins through their respective corresponding powder conveying pipes. The powder nozzles of different materials and the binder nozzle are fixed on a disk, and the disk drives the nozzles to achieve precise movement and rotation in the X-Y plane, so as to achieve coaxial precise powder feeding and binder spraying.

5. The gradient functional material BJ printing device based on an array nozzle according to claim 1, characterized in that After the binder nozzle sprays the binder onto the printing substrate according to the graphics designed by computer-aided design, the powder nozzle accurately conveys the corresponding powder to the sprayed binder through coaxial movement to achieve the fixation of the powder body, reduce the dusting of the powder and the disturbance after the powder falls.

6. The gradient functional material BJ printing device based on an array nozzle according to claim 1, characterized in that, A powder feeding flow detection device is provided in the powder conveying pipe. The powder feeding flow detection device includes a diode laser and a photodiode arranged oppositely. Among them: the laser beam emitted by the diode laser passes horizontally through the gas-powder particle flow in the powder conveying pipe and is received by the photodiode; when the powder feeding flow fluctuates, the diffuse reflection, absorption and reflection of the laser by the gas-powder particle flow will change, resulting in a change in the laser energy received by the photodiode, and its output voltage also changes accordingly; by using the quantitative relationship between the output voltage and the powder feeding flow, the real-time detection of the gas-powder particle flow can be realized.

7. The gradient functional material BJ printing device based on an array nozzle according to claim 1, characterized in that, A piezoelectric switch valve is provided in the powder conveying pipe.

8. A method for preparing a ceramic / ceramic / ceramic integrated ceramic shell and ceramic core based on the device according to any one of claims 1-7, characterized in that, Including: 1) After designing the model of the ceramic / ceramic / ceramic integrated ceramic shell and ceramic core through auxiliary software and performing slicing processing, the obtained sliced model is imported into a BJ printer equipped with an array of multiple nozzles; 2) Configuring the raw and auxiliary materials, including: epoxy resin and / or furan resin as the binder, and corundum powder, zircon powder, mullite powder, quartz powder and / or yttrium oxide powder as the ceramic powder; 3) After setting the printing parameters for printing, the obtained green body is subjected to impregnation strengthening and roasting treatment.

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