An in-situ electric pulse assisted additive manufacturing 3D printing device and method

Abstract

This invention relates to the field of additive manufacturing technology and provides an in-situ electrical pulse-assisted additive manufacturing 3D printing apparatus and method. The apparatus includes an additive manufacturing device and a power supply device. The additive manufacturing device contains an insulating substrate and a printing substrate for supporting the 3D printed workpiece. The insulating substrate is located at the bottom and / or side of the printing substrate. The power supply device has a pulse current module connected to a first set of electrical pulse cables. The first set of electrical pulse cables includes a first positive cable and a first negative cable, which pass through the insulating substrate and are arranged opposite to each other and respectively connected to both sides of the printing substrate. The in-situ electrical pulse-assisted additive manufacturing 3D printing apparatus and method provided by this invention achieves in-situ pulse electrical stimulation during the printing process without changing current mass-produced 3D printing equipment, which helps to eliminate defects in the 3D printed workpiece and improves the performance of the 3D printed workpiece.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, and particularly relates to an in-situ electrical pulse-assisted additive manufacturing 3D printing device and method. Background Technology

[0002] Additive manufacturing (AM) technology (3D printing technology) is a technique for manufacturing solid parts by gradually adding materials. Compared to traditional material removal and machining techniques, additive manufacturing involves the gradual addition of raw materials during the manufacturing process. In contrast, traditional methods such as arc melting, rolling, forging, and deep drawing require further machining and cutting, all of which are subtractive processes. Additive manufacturing has several significant advantages over traditional manufacturing methods:

[0003] 1. Can print structurally complex parts.

[0004] 2. High raw material utilization rate

[0005] 3. High formability.

[0006] In the process of fabricating parts using additive manufacturing equipment, although the material can be shaped, internal microcracks, pores, and other structural defects often occur, severely affecting the material's service performance. To address this problem, current methods mainly involve applying electrical pulses to the printed part to alter its microstructure and achieve densification. However, this is a post-processing method after forming, and based on current reports, the results are not very satisfactory. Existing technologies also include methods that apply pulsed currents in different directions to the substrate, but the pulsed current cannot flow sufficiently through the 3D printed workpiece, resulting in less than ideal results. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide an in-situ electrical pulse-assisted additive manufacturing 3D printing device and method. Without changing the current mass-produced 3D printing equipment, it introduces pulse current into the printing substrate to realize in-situ pulse electrical stimulation during the printing process, which helps to eliminate cracks and structural defects in 3D printed workpieces and improves the performance of 3D printed workpieces.

[0008] The technical solution of the present invention is: an in-situ electrical pulse-assisted additive manufacturing 3D printing device, comprising an additive manufacturing device and a power supply device. The additive manufacturing device is provided with an insulating substrate and a printing substrate for supporting the 3D printed workpiece. The insulating substrate is located at the bottom and / or side of the printing substrate. The power supply device has a pulse current module, which is connected to a first set of electrical pulse cables. The first set of electrical pulse cables includes a first positive cable and a first negative cable. The first positive cable and the first negative cable pass through the insulating substrate and are arranged opposite to each other and respectively connected to both sides of the printing substrate.

[0009] Optionally, the front side of the insulating substrate is provided with a mounting groove, and the printing substrate is mounted in the mounting groove;

[0010] A first wiring terminal is provided on one side of the bottom of the printing substrate, and a second wiring terminal is provided on the other side of the bottom of the printing substrate. The first positive cable is connected to the first wiring terminal, and the first negative cable is connected to the second wiring terminal.

[0011] Optionally, a leveling substrate is provided at the bottom of the insulating substrate, and both the leveling substrate and the insulating substrate are provided with wire through holes.

[0012] Optionally, the pulse current module is also connected to a second set of electrical pulse cables, which are connected to contact components for contacting the 3D printed workpiece.

[0013] Optionally, the contact component includes a resilient pin.

[0014] Optionally, the contact component is connected to a displacement driving component.

[0015] Optionally, the printing substrate is connected to a first temperature sensing device for monitoring the temperature of the printing substrate, and / or a second temperature sensing device for monitoring the temperature of the 3D printed workpiece is disposed above the printing substrate.

[0016] Optionally, the power supply is a power cabinet that is independent of the additive manufacturing apparatus; or, the power supply is integrated inside the additive manufacturing apparatus.

[0017] Optionally, the additive manufacturing apparatus includes a laser component disposed above the printing substrate, a hopper disposed on one side of the printing substrate for containing metal powder raw materials, and a scraping component disposed above the hopper for scraping metal powder of a set thickness from the hopper onto the printing substrate or 3D printed workpiece.

[0018] This invention also provides an in-situ electrical pulse-assisted additive manufacturing 3D printing method, which uses the above-mentioned in-situ electrical pulse-assisted additive manufacturing 3D printing apparatus and includes the following steps:

[0019] Before or during the layering process on the printing substrate by the additive manufacturing apparatus, a pulse current is passed through the printing substrate and / or the 3D printed workpiece via a pulse current module and a first set of electrical pulse cables.

[0020] The present invention provides an in-situ electrical pulse-assisted additive manufacturing 3D printing device and method, which introduces pulse current into the printing substrate without changing the current mass-produced 3D printing equipment, to achieve in-situ pulse electrical stimulation during the printing process, which helps to eliminate cracks and structural defects in 3D printed workpieces and improves the performance of 3D printed workpieces. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram illustrating the working principle of an in-situ electrical pulse-assisted additive manufacturing 3D printing device provided in an embodiment of the present invention;

[0023] Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle;

[0024] Figure 3 This is a three-dimensional exploded view of the printing substrate, insulating substrate, and leveling substrate in an in-situ electrical pulse-assisted additive manufacturing 3D printing device provided in an embodiment of the present invention.

[0025] Figure 4 This is another exploded perspective view of the printing substrate, insulating substrate, and leveling substrate in an in-situ electrical pulse-assisted additive manufacturing 3D printing device provided in an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or may have an intervening component present. When a component is referred to as "connected to" another component, it can be directly connected to the other component or may have an intervening component present.

[0028] Furthermore, in embodiments of this invention, terms such as "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are used to indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, or in a conventional placement or usage state. These terms are merely for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the structures, features, devices, or elements referred to must have a specific orientation or positional relationship, nor that they must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] The various specific technical features and embodiments described in the detailed embodiments can be combined in any suitable manner without contradiction. For example, different implementation methods can be formed by combining different specific technical features / embodiments. In order to avoid unnecessary repetition, the various possible combinations of the various specific technical features / embodiments in this invention will not be described separately.

[0030] like Figures 1 to 4As shown in the figure, an in-situ electrical pulse-assisted additive manufacturing 3D printing device provided by an embodiment of the present invention includes an additive manufacturing device and a power supply device 20. The additive manufacturing device 10 contains an insulating substrate 120 and a printing substrate 110 for supporting the 3D printed workpiece. The 3D printed workpiece is conductive and can be made of metal or conductive composite materials, etc. The front side of the printing substrate 110 is in direct contact with the 3D printed workpiece, and the printing substrate 110 is connected to the power supply device 20. The insulating substrate 120 is located at the bottom and / or side of the printing substrate 110 to prevent potential hazards such as leakage. The power supply device 20 has a pulse current module that can output a pulse current of a set intensity and a set period. The pulse current module is connected to a first set of electrical pulse cables 210, which includes a first positive cable 211 and a first negative cable 212. The first positive cable 211 and the first negative cable 212 pass through the insulating substrate 120. The first positive cable 211 and the first negative cable 212 are arranged opposite to each other and are respectively connected to both sides of the printing substrate 110. This allows the pulse current to flow fully through the substrate and the 3D printed workpiece. Without changing the current mass-produced 3D printing equipment, the pulse current is introduced into the printing substrate 110 to achieve in-situ pulse electrical stimulation during the printing process. When the pulse current passes through the 3D printed workpiece (metal material), it generates a large number of directional drifting free electrons (electron wind). Frequent, directional collisions of drifting electrons with dislocations create an electron wind similar to applied stress on the dislocation segments, promoting the movement of dislocations on their slip surfaces. When a pulsed current is applied, electrical energy, thermal energy, and stress are instantaneously input into the material. The random thermal motion of atoms gains sufficient kinetic energy to leave their equilibrium positions under the instantaneous impact force of the pulsed current, enhancing the diffusion ability of atoms and making dislocations easier to slip and climb. This helps eliminate cracks and structural defects in 3D printed workpieces, resulting in better performance of the 3D printed workpieces.

[0031] Specifically, the front side of the insulating substrate 120 is provided with a mounting groove 121, and the printing substrate 110 is mounted in the mounting groove 121, which has high reliability. The front side of the printing substrate 110 can be flush with or slightly protruding from the front side of the insulating substrate 120. Of course, the front side of the printing substrate 110 can also be lower than the front side of the insulating substrate 120.

[0032] Specifically, a first terminal block 111 is provided on one side of the bottom of the printing substrate 110, and a second terminal block 112 is provided on the other side of the bottom of the printing substrate 110. The first positive cable 211 is connected to the first terminal block 111, and the first negative cable 212 is connected to the second terminal block 112. The first terminal block 111 and the second terminal block 112 are wiring holes, and both the first terminal block 111 and the second terminal block 112 are directly formed on the printing substrate 110. In specific applications, clearance grooves 113 are respectively provided on the opposite sides of the printing substrate 110 near the bottom, and the clearance grooves 113 penetrate through the side and bottom surfaces of the printing substrate 110. The first terminal block 111 and the second terminal block 112 are respectively provided on the bottom wall of the clearance groove 113. The front ends of the first positive cable 211 and the first negative cable 212 may be provided with plug terminals. The plug terminals may be interference-connected to the first terminal 111 and the second terminal 112, or reliably connected to the first terminal 111 and the second terminal 112 by means of locking elements (such as bolts or clamps).

[0033] In specific applications, the printing substrate 110 can be an integral metal substrate. Specifically, a groove can be provided on the bottom surface of the printing substrate 110, located between the first terminal 111 and the second terminal 112, to facilitate better current flow through the 3D printed workpiece. Alternatively, the printing substrate 110 can be entirely flat, comprising a first metal plate, a second metal plate, and an intermediate connecting plate. The intermediate connecting plate has a higher resistivity. The first and second metal plates are located on both sides of the intermediate connecting plate, and the first terminal 111 and the second terminal 112 are respectively located on the first and second metal plates, allowing the 3D printed workpiece to be simultaneously connected to the first metal plate.

[0034] Specifically, a leveling substrate 130 is provided at the bottom of the insulating substrate 120. Both the leveling substrate 130 and the insulating substrate 120 are provided with wire holes. The leveling substrate 130 is connected to a leveling component so that the printing substrate 110 can be adjusted to the required state such as horizontal.

[0035] Specifically, as an optional implementation, the pulse current module is further connected to a second set of electrical pulse cables, which are connected to a contact component for contacting the 3D printed workpiece. One cable of the second set of electrical pulse cables can be connected to the printing substrate 110, and the other cable can be connected to the contact component. In practical applications, after the 3D printed workpiece completes the forming of a set number of layers or a set height, the contact component moves to contact the top of the 3D printed workpiece, and a set pulse current is passed through the second set of electrical pulse cables, allowing the pulse current to flow longitudinally through the 3D printed workpiece. This results in a denser bond between adjacent forming layers of the 3D printed workpiece, which is more conducive to eliminating interlayer defects.

[0036] Specifically, the contact component includes an elastic ejector pin to prevent rigid collision with the 3D printed workpiece. The contact component may be connected to a displacement driving component, which can move and rise under the action of the displacement driving component without affecting the layer-by-layer deposition of the 3D printed workpiece. The lifting and moving component may be a robotic arm component.

[0037] Specifically, the printing substrate 110 is connected to a first temperature sensing device for monitoring the temperature of the printing substrate 110, which can adjust the current according to the temperature of the printing substrate 110.

[0038] Specifically, a second temperature sensing device for monitoring the temperature of the 3D printed workpiece is provided above the printing substrate 110, and the current can be adjusted according to the temperature of the 3D printed workpiece.

[0039] Specifically, the power supply device 20 is a power cabinet that is independent of the additive manufacturing apparatus 10; or, the power supply device 20 is integrated inside the additive manufacturing apparatus 10.

[0040] Specifically, the additive manufacturing apparatus 10 includes a laser component disposed above the printing substrate 110, a hopper disposed on one side of the printing substrate 110 for containing metal powder raw materials, and a scraping component disposed above the hopper for scraping metal powder of a set thickness from the hopper onto the printing substrate 110 or the 3D printed workpiece. Through holes can be provided in the front or rear cover plate of the 3D printer (additive manufacturing apparatus 10), with two first-set electrical pulse cables (which can be cables with a cross-section of not less than 10 square centimeters) entering the 3D printer through the through holes. After entering the 3D printer, the cables run from the bottom of the printer, through the forming shaft of the 3D printer, and successively through a customized leveling substrate 130, a heat insulation substrate, and an insulating substrate 120 to reach the bottom of the printing substrate 110, and then connect through two connection ports at the bottom of the printing substrate 110.

[0041] This invention also provides an in-situ electrical pulse-assisted additive manufacturing 3D printing method, which uses the in-situ electrical pulse-assisted additive manufacturing 3D printing apparatus as described above, and includes the following steps:

[0042] Before or during the layering process on the printing substrate 110 by the additive manufacturing apparatus 10, a pulse current is passed through the printing substrate 110 and / or the 3D printed workpiece via a pulse current module and a first set of electrical pulse cables 210. The power supply device 20 has a voltage adjustment knob and a frequency adjustment knob. The voltage adjustment knob controls the output voltage, and the frequency adjustment knob controls the frequency of the pulse current. In this embodiment, the voltage range can be 0-130V, and the frequency range can be 0-800Hz. In specific applications, the frequency of the pulse current can be greater than 400Hz. That is, by using high-frequency pulse current, a skin effect can be achieved on the 3D printed workpiece, causing uneven current distribution inside the 3D printed workpiece. The current is concentrated in the "skin" part of the conductor (3D printed workpiece); that is, the current is concentrated in a thin layer on the surface of the conductor (3D printed workpiece), and the current density is greater closer to the conductor surface, while the actual current inside the conductor is smaller. Without altering existing mass-production 3D printing equipment, pulsed current can be introduced into the printing substrate 110 to achieve in-situ pulsed electrical stimulation during the printing process. When the pulsed current passes through the 3D printed workpiece (metal material), it generates a large number of directional drifting free electrons (electron wind). The frequent directional collisions of these drifting electron groups with dislocations create an electron wind force on the dislocation segments, similar to applied stress, promoting the movement of dislocations on their slip surfaces. When pulsed current is applied, electrical energy, thermal energy, and stress are instantaneously input into the material. The random thermal motion of atoms gains sufficient kinetic energy to leave their equilibrium positions under the instantaneous impact force of the pulsed current, enhancing atomic diffusion and making dislocations easier to slip and climb. This helps eliminate cracks and structural defects in the 3D printed workpiece, resulting in better performance.

[0043] This invention provides an in-situ electrical pulse-assisted additive manufacturing 3D printing device and method. Without altering existing mass-produced 3D printing equipment, it introduces pulsed current into the printing substrate 110 to achieve in-situ pulsed electrical stimulation during the printing process. When the pulsed current passes through the 3D-printed workpiece (metal material), it generates a large number of directionally drifting free electrons (electron wind). The frequent directional collisions of these drifting electrons with dislocations create an electron wind force similar to applied stress on the dislocation segments, promoting the movement of dislocations on their slip surfaces. When pulsed current is applied, electrical energy, thermal energy, and stress are instantaneously input into the material. The random thermal motion of atoms gains sufficient kinetic energy to leave their equilibrium positions under the instantaneous impact force of the pulsed current, enhancing atomic diffusion and making dislocations easier to slip and climb. Simultaneously, utilizing the skin effect, the current distribution inside the 3D-printed workpiece becomes uneven, with the current concentrated in the "skin" of the conductor (3D-printed workpiece), which helps eliminate cracks and structural defects in the 3D-printed workpiece, resulting in better performance.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An in-situ electro-pulse assisted additive manufacturing 3D printing device, characterized in that, The device includes an additive manufacturing apparatus and a power supply. The additive manufacturing apparatus is provided with an insulating substrate and a printing substrate for supporting 3D printed workpieces. The insulating substrate is located at the bottom and side of the printing substrate. The power supply device has a pulse current module for outputting pulse current with a set intensity and a set period. The power supply device has a voltage adjustment knob and a frequency adjustment knob. The frequency range of the pulse current is 400-800Hz. The pulse current module is connected to a first set of electrical pulse cables. The first set of electrical pulse cables includes a first positive cable and a first negative cable. The first positive cable and the first negative cable pass through the insulating substrate. The first positive cable and the first negative cable are arranged opposite to each other and are respectively connected to both sides of the printing substrate. A leveling substrate is provided at the bottom of the insulating substrate. Both the leveling substrate and the insulating substrate are provided with wire through holes. The additive manufacturing apparatus includes a laser component disposed above the printing substrate and a hopper disposed on one side of the printing substrate for containing metal powder raw materials. The additive manufacturing apparatus also includes a scraping component disposed above the hopper for scraping metal powder of a set thickness from the hopper onto the printing substrate or 3D printed workpiece. A through hole is provided on the front or rear cover plate of the additive manufacturing apparatus. Two first-set electrical pulse cables enter and exit through the through hole. The first-set electrical pulse cables are cables with a cross-section of not less than 10 square centimeters and enter the additive manufacturing apparatus through the through hole. After entering the additive manufacturing apparatus, the cables pass through the forming shaft of the additive manufacturing apparatus from the bottom, and successively pass through the leveling substrate, the heat insulation substrate, and the insulating substrate to reach the bottom of the printing substrate. Then, they are connected through two connection ports at the bottom of the printing substrate. The front side of the insulating substrate is provided with a mounting groove, and the printing substrate is installed in the mounting groove. The front side of the printing substrate is flush with the front side of the insulating substrate; the printing substrate is connected to a first temperature sensing device for monitoring the temperature of the printing substrate, and a second temperature sensing device for monitoring the temperature of the 3D printed workpiece is provided above the printing substrate. The printing substrate is an integral metal substrate. A first terminal is provided on one side of the bottom of the printing substrate, and a second terminal is provided on the other side of the bottom of the printing substrate. The first positive cable is connected to the first terminal, and the first negative cable is connected to the second terminal. The first and second terminals are wiring holes, and both the first and second terminals are directly formed on the printing substrate. Recessed grooves are provided on opposite sides of the printing substrate near the bottom. The recessed grooves penetrate the side and bottom surfaces of the printing substrate. The first and second terminals are respectively provided on the bottom walls of the recessed grooves. The front ends of the first positive and first negative cables are provided with plug terminals, which are interference-fitted to the first and second terminals. A partition groove is provided on the bottom surface of the printing substrate, and the partition groove is located between the first and second terminals.

2. An in-situ electric pulse assisted additive manufacturing 3D printing device as claimed in claim 1, wherein, The pulse current module is also connected to a second set of electrical pulse cables, which are connected to contact components for contacting the 3D printed workpiece. After the 3D printed workpiece completes the forming of a set number of layers or a set height, the contact components move to contact the top of the 3D printed workpiece and pass a set pulse current through the second set of electrical pulse cables.

3. An in-situ electric pulse assisted additive manufacturing 3D printing device as claimed in claim 2, wherein, The contact component includes a resilient pin.

4. An in-situ electric pulse assisted additive manufacturing 3D printing device as claimed in claim 2, wherein, The contact component is connected to a displacement driving component.

5. An in-situ electro-pulse assisted additive manufacturing 3D printing method, characterized in that, The in-situ electrical pulse-assisted additive manufacturing 3D printing apparatus according to any one of claims 1 to 4 includes the following steps: Before or during the layering process on the printing substrate in the additive manufacturing apparatus, a pulse current is introduced into the printing substrate and / or the 3D printed workpiece through a pulse current module and a first set of electrical pulse cables. The frequency range of the pulse current is 400-800Hz. The 3D printed workpiece made of metal material is in direct contact with the front surface of the printing substrate. The pulse current is concentrated on the thin layer on the surface of the 3D printed workpiece, thereby achieving in-situ pulse electrical stimulation during the printing process.

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