3D printing device forming method and 3D printing head

Abstract

The application relates to a 3D printing device forming method, which comprises the following steps: preparing metal substrates; processing positioning holes and micro-channel through holes on the metal substrates respectively; manufacturing active metal plating layers on the bonding surfaces of the metal substrates; stacking all the processed metal substrates in a preset order on a positioning tool to make the micro-channel through holes on the metal substrates aligned and communicated to form internal micro-channels; applying pre-tightening force on the metal substrates through a fastening mechanism on the positioning tool to make the metal substrates closely adhere to each other; placing the stacked structure in a vacuum environment to heat and apply pressure for diffusion bonding, so that the metal substrates are combined to form an integrated 3D printing device. The application also relates to a 3D printing head. The scheme can solve the problems of seal failure of the adhesive jet 3D printing head caused by insufficient ink corrosion resistance of the adhesive in the prior art.

Description

Technical Field

[0001] This invention relates to the field of 3D printing equipment technology, and in particular to a 3D printing device forming method and a 3D printing head. Background Technology

[0002] Binder jetting is a powder bed additive manufacturing process whose core component is the printhead. This printhead typically consists of an orifice plate, a base (or manifold), ink channels, and piezoelectric / thermal bubble drive elements. During operation, the printhead selectively jets binder ink onto the powder bed surface along a preset trajectory, bonding powder material layer by layer to build a three-dimensional solid. The orifice plate, as a precision thin sheet at the end of ink jetting, is densely covered with micron-sized nozzles. The interface between the orifice plate and the base must simultaneously meet extremely high requirements for structural positioning accuracy, vibration resistance, and chemical resistance to long-term contact with organic solvent-based inks. It is a critical bonding area that determines print quality and reliability.

[0003] Currently, the mainstream method for fixing the nozzle plate to the base is using organic adhesives. However, this process has significant technical risks. Adhesive-jet inks typically contain strong solvents such as alcohols, ketones, or hydrocarbons, while conventional epoxy resins or acrylic adhesives are prone to swelling, softening, and even chemical degradation under long-term immersion conditions, leading to a gradual loss of adhesive strength and sealing performance. With accumulated printing cycles, micro-cracks or localized detachment can develop at the adhesive interface, causing ink leakage from the joint gaps. Ink leakage not only causes unstable pressure in the printhead's internal flow channels, ink jet interruptions, or an increase in satellite droplets, but in severe cases, it can corrode the drive circuit or contaminate the powder bed, rendering the entire printhead assembly unusable. This sealing failure due to insufficient chemical resistance of the adhesive has become one of the main bottlenecks restricting the service life of printheads and the long-term operational stability of equipment. Summary of the Invention

[0004] Therefore, it is necessary to provide a 3D printing device forming method and a 3D printing head to address the problems in existing adhesive jet 3D printing heads, such as sealing failure due to insufficient resistance of the adhesive to ink corrosion.

[0005] To solve the above problems, the present invention adopts the following technical solution: In a first aspect, embodiments of the present invention disclose a 3D printing device forming method, comprising: Prepare the metal substrates for each layer; Positioning holes and microchannel vias are fabricated on each layer of the metal substrate; An active metal plating layer is formed on the bonding surface of each of the metal substrates; All the processed metal substrates of each layer are stacked on the positioning fixture in a preset order, so that the microchannels on each layer of the metal substrate are aligned and connected to form internal microchannels. Pre-tightening force is applied by the fastening mechanism on the positioning fixture to ensure that the metal substrates of each layer are tightly bonded together. The stacked and aligned overall structure is placed in a vacuum environment, heated, and pressure is applied for diffusion bonding, so that the metal substrates of each layer are combined to form a whole 3D printing device.

[0006] In one embodiment, the microchannel vias are fabricated on each metal substrate layer, and the microchannel vias are fabricated using a combined processing method: first, guide holes are pre-fabricated on the metal substrate using laser processing, and then, based on the guide holes, the final forming of the microchannel vias is completed using chemical etching.

[0007] In one embodiment, after machining positioning holes and microchannel vias on each layer of the metal substrate, the method further includes cleaning each layer of the metal substrate with ultrapure water.

[0008] In one embodiment, the material of the active metal coating is gold, silver, copper, nickel, or an alloy thereof.

[0009] In one embodiment, the thickness of the active metal coating is 5-20 μm.

[0010] In one embodiment, the step of placing the stacked and aligned overall structure in a vacuum environment, heating it, and applying pressure for diffusion bonding specifically includes: The stacked and aligned overall structure is placed in a vacuum hot press furnace and a vacuum is drawn. Then, the temperature is raised to the preset bonding temperature and vertical pressure is applied to maintain the temperature and pressure. After cooling, the metal substrates of each layer are bonded together to form an integral structure.

[0011] In one embodiment, the vacuum level of the vacuum environment is 1×10^(-5)-1×10^(-1) Pa; the heating temperature is 800-1500°C; the applied pressure is 0.1-1 MPa; and the heat and pressure holding time is 1-3 hours.

[0012] In one embodiment, the positioning fixture includes a base, at least two positioning posts vertically disposed on the base, and a pressure plate that can slide along the axial direction of the positioning posts. The fastening mechanism includes a locking member disposed above the pressure plate, and a preload force in the vertical direction is applied to each layer of the metal substrate by tightening the locking member.

[0013] In one embodiment, the thickness of each layer of the metal substrate is 0.05 mm to 0.5 mm.

[0014] Secondly, embodiments of the present invention disclose a 3D printing head, which is manufactured using the 3D printing apparatus forming method described above.

[0015] The technical solution adopted in this invention can achieve the following beneficial effects: The 3D printing device molding method disclosed in this invention achieves high-strength metallurgical bonding between multi-layer metal substrates through a technical route of "all-metal substrate selection + active metal coating intermediate transition + one-time overall stacking + vacuum diffusion bonding". This method completely abandons traditional organic adhesives and uses a high-temperature and high-pressure diffusion bonding process to achieve atomic-level metallurgical bonding between metal substrates, fundamentally eliminating the risks of swelling, aging, and degradation of adhesives in strong solvents such as alcohols and ketones. The active metal coating does not melt during the bonding process, avoiding the risk of contamination or blockage caused by molten filler material flowing into the microchannels. At the same time, it avoids the cumulative damage to the microstructure and properties of the metal substrates caused by multiple thermal cycles, meeting the stringent requirements of high-precision 3D printing for fluid dynamic behavior. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the 3D printing device disclosed in an embodiment of the present invention; Figure 2 for Figure 1 A magnified view of a portion of the image; Figure 3 This is a schematic diagram of the structure of the metal substrate disclosed in an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 100 - Metal substrate, 110 - Positioning hole, 120 - Microchannel through hole. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0019] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," "top," "bottom," "end," "top," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] like Figures 1-3 As shown in the figure, this invention discloses a method for forming a 3D printing device, which specifically includes the following steps: Prepare the various metal substrates 100. Each metal substrate 100 can be used to form different functional layers of the 3D printing head. These functional layers include, but are not limited to, nozzle plates, flow dividers, and bases.

[0022] The material of each metal substrate 100 can be any one or a combination of stainless steel, nickel-based alloy, titanium alloy, and copper alloy. Preferably, each metal substrate 100 uses a metal material with the same or similar coefficient of thermal expansion to ensure that the deformation of each substrate is consistent during the heating and cooling process of diffusion bonding. More preferably, the material of each metal substrate 100 is 304 stainless steel or 316L stainless steel, which has excellent diffusion welding performance and low cost.

[0023] Positioning holes 110 and microchannel vias 120 are machined on each layer of the metal substrate 100. Specifically, firstly, positioning holes 110 are machined in one step on each layer of the metal substrate 100 using a milling cutter. The machining of positioning holes 110 precedes the machining of microchannel vias 120, and positioning holes 110 serve as a unified reference for the subsequent machining and stacking alignment of each layer of the metal substrate 100. That is, from the independent machining of each layer of the substrate to the final overall stacking, the same set of positioning references is used, thereby effectively eliminating the cumulative errors caused by multiple clamping and positioning in traditional processes.

[0024] Positioning holes 110 are provided at the same relative position on each layer of metal substrate 100. There are at least two positioning holes 110 on each layer of metal substrate 100. The number of positioning pins of the positioning fixture is the same as the number of positioning holes 110 and their positions correspond one-to-one, so as to achieve "one side and two pins" positioning, while restricting the translational and rotational degrees of freedom of the substrate in the horizontal plane.

[0025] Then, a laser processing technique can be used to pre-fabricate micro-guide holes on the metal substrate 100. The diameter of the guide holes is smaller than the final diameter of the microchannel via 120, and the guide holes are located at the geometric center of the microchannel via 120.

[0026] Subsequently, using the guide hole as a reference, the final forming of the microchannel via 120 is completed by chemical etching. Specifically, an anti-corrosion layer is formed on the surface of the metal substrate 100, the area around the guide hole is patterned to expose the area to be etched, the patterned metal substrate 100 is placed in an etching solution, and isotropic etching is performed by controlling the etchant concentration, temperature and time, so that the etching solution spreads uniformly from the guide hole to the surrounding area until the microchannel via 120 through the metal substrate 100 is formed.

[0027] This combined processing method of "laser pre-fabrication of guide holes + chemical etching" ensures both the dimensional accuracy of micron-level through holes and the smoothness of the inner wall.

[0028] After processing, each layer of the metal substrate 100 is rigorously cleaned with ultrapure water to remove surface oil, oxide layer, and processing residues, ensuring the cleanliness of the substrate surface. Specifically, each layer of the metal substrate 100 can be sequentially immersed in ultrapure water for ultrasonic cleaning for 5-30 minutes, followed by high-pressure spray rinsing with ultrapure water, and finally dried with inert gas, thereby effectively preventing contamination of the bonding interface or blockage of the flow channels in subsequent bonding processes.

[0029] Furthermore, an active metal plating layer is formed on the bonding surfaces of each metal substrate 100. Specifically, an active metal plating layer is prepared on the bonding surfaces of the cleaned and dried metal substrate 100.

[0030] The active metal coating is made of gold, silver, copper, nickel, or alloys thereof. It can be deposited on the bonding surfaces of each metal substrate 100 using electroplating, electroless plating, physical vapor deposition (PVD), or chemical vapor deposition (CVD) processes. The active metal coating covers the entire bonding surface of each metal substrate 100 to ensure that an active metal transition layer exists throughout the bonding interface, avoiding insufficient bonding in areas without coating.

[0031] The thickness of the active metal coating can be 5-20 μm, preferably 7-15 μm. This active metal coating serves as an intermediate transition layer to reduce the bonding activation energy and effectively promotes atomic interdiffusion and recrystallization between the various metal substrate layers 100 under subsequent high temperature and high pressure conditions, laying the foundation for high-strength metallurgical bonding. This coating does not melt during the bonding process and will not clog the flow channels or vias, unlike the brazing process in existing technologies where the filler material melts to achieve the connection.

[0032] All the processed metal substrates 100 are stacked in a predetermined order on a positioning fixture at once, so that the microchannel vias 120 on each metal substrate 100 are aligned and connected to form internal microchannels. This step adopts a one-time overall stacking method for assembly, that is, all the processed metal substrates 100 are stacked in a predetermined order at once, and then the whole assembly is put into the furnace for bonding, rather than being done in batches.

[0033] During assembly, the cleaned metal substrates 100 can be sequentially fitted onto the positioning posts of the positioning fixture in a preset order (e.g., base-distribution plate-orifice plate). The positioning posts are only inserted into the non-functional areas at the edges of each metal substrate 100 to avoid interference or damage to the functional areas of the microchannels, ensuring the structural integrity of the microchannel vias 120. The fit tolerance between the positioning posts and the positioning holes 110 is controlled within 10μm to ensure the relative positional accuracy between the substrates.

[0034] After each metal substrate 100 is fitted into the positioning post, the microchannel vias 120 on each metal substrate 100 are aligned and connected to each other to form an internal microchannel. This internal microchannel is a complete ink flow path from the ink supply channel through the distribution channel to the nozzle array.

[0035] A pre-tightening force is applied by a fastening mechanism on the positioning fixture to ensure that each layer of metal substrate 100 is tightly bonded. Specifically, after stacking, the pressure plate is slid along the axial direction of the positioning post above each layer of metal substrate 100. The fastening mechanism may include a locking member disposed above the pressure plate. By tightening the locking member, a vertical pre-tightening force is applied to each layer of metal substrate 100 to ensure that each layer of metal substrate 100 is tightly bonded and has no relative displacement before entering the hot press furnace.

[0036] The stacked and aligned overall structure is placed in a vacuum environment, heated, and pressure is applied for diffusion bonding, so that the various metal substrates 100 are combined to form a single 3D printing device. In this step, the fixed stack is placed in a vacuum hot press furnace for bonding.

[0037] First, the stacked and aligned overall structure is placed in a vacuum hot press furnace and evacuated to 1×10^(-5)-1×10^(-1) Pa to remove air between the interfaces of each metal substrate layer 100, prevent the metal substrate from oxidizing at high temperature, and provide a pure interface environment for atomic diffusion.

[0038] Then, the vacuum hot press furnace is heated to the preset bonding temperature of 800-1500°C at a heating rate of 0.5-2°C / min. This temperature is much lower than the melting point of each metal substrate layer 100. Vacuum is continuously evacuated during the heating process to maintain the vacuum level. Simultaneously, a vertical pressure of 0.1-1 MPa is applied through the upper pressure head of the vacuum hot press furnace. The pressure application area of ​​the upper pressure head covers the entire upper surface of the overall structure to ensure uniform pressure distribution and avoid substrate deformation or incomplete bonding caused by localized pressure concentration.

[0039] Maintaining the temperature and pressure at these parameters for 1-3 hours allows for sufficient atomic diffusion and recrystallization between the active metal coating and the base metal.

[0040] After the heat and pressure holding are completed, while maintaining a constant vertical pressure, the temperature of the vacuum hot press furnace is slowly cooled to room temperature at a rate of 0.5-3℃ / min. Slow cooling and pressure holding cooling avoid thermal stress and interface cracks caused by sudden temperature drops, ensuring that the interface remains in close contact after the interface atomic diffusion and recrystallization are completed and during the cooling and shrinkage process.

[0041] After cooling, the various metal substrates 100 are metallurgically bonded together to form a single 3D printing head structure. This metallurgical bonding interface is a continuous, gapless, atomic-level bonding interface, achieving a permanent airtight and liquid-tight connection.

[0042] As can be seen from the above, the 3D printing device molding method disclosed in this invention achieves high-strength metallurgical bonding between multi-layer metal substrates through the technical route of "all-metal substrate selection + active metal coating intermediate transition + one-time overall stacking + vacuum diffusion bonding". This method completely abandons traditional organic adhesives and uses high-temperature and high-pressure diffusion bonding process to achieve atomic-level metallurgical bonding between metal substrates, fundamentally eliminating the risk of swelling, aging and degradation of adhesives in strong solvents such as alcohols and ketones; the active metal coating does not melt during the bonding process, avoiding the risk of molten filler material flowing into the microchannels and causing pollution or blockage, while avoiding the cumulative damage to the microstructure and properties of the metal substrates caused by multiple thermal cycles, thus meeting the stringent requirements of high-precision 3D printing for fluid dynamic behavior.

[0043] In this embodiment of the invention, in the steps of processing positioning holes 110 and microchannel vias 120 on each layer of the metal substrate 100, the processing of the microchannel vias 120 can be carried out using a combined processing method: first, a guide hole can be pre-fabricated on the metal substrate 100 using laser processing technology, and then, using the guide hole as a reference, a chemical etching process can be used to complete the final forming of the microchannel via 120. In this case, the laser guide hole provides a precise starting positioning reference for chemical etching, avoiding the problems of uncertain etching start point and uneven etching caused by the lack of an initial guide hole in traditional chemical etching; isotropic etching allows the etching solution to spread uniformly from the guide hole to the surrounding area, with a smooth transition of the hole wall and the inner wall roughness can be controlled within Ra≤0.4μm, which is beneficial to the smooth flow of ink fluid.

[0044] Furthermore, the guide hole is located at the geometric center of the final flow channel, ensuring the concentricity and dimensional consistency of the flow channel after forming. This combined processing method takes into account both the dimensional accuracy of the micron-level through hole (the hole diameter tolerance can be controlled within ±5μm) and the smoothness of the inner wall, which has significant advantages over single laser processing (which has a heat-affected zone and recast layer) or single chemical etching (which is difficult to position precisely).

[0045] In this embodiment of the invention, after processing positioning holes 110 and microchannel vias 120 on each layer of the metal substrate 100, the process may further include cleaning the processed metal substrates 100 with ultrapure water. Ultrapure water cleaning effectively removes oil, oxide layers, and processing residues (such as etching residues and photoresist residues) from the substrate surface, ensuring the cleanliness of the substrate surface and preventing contamination of subsequent bonding interfaces or blockage of the flow channels. Ultrasonic cleaning utilizes the cavitation effect of ultrasound to peel off fine residues inside the microchannel vias 120; high-pressure spray rinsing thoroughly removes the peeled contaminants; and inert gas drying avoids secondary contamination caused by dust in the air during the drying process. This three-stage cleaning process of "ultrasonic cleaning + high-pressure spray rinsing + inert gas drying" ensures the thoroughness and reliability of the cleaning.

[0046] In one optional embodiment, the active metal coating can be made of gold, silver, copper, nickel, or alloys thereof. All of these metal materials possess excellent diffusion properties, effectively reducing bonding activation energy and promoting interlayer atomic diffusion as an intermediate transition layer. Gold coatings exhibit excellent chemical stability and electrical conductivity, making them suitable for applications requiring high corrosion resistance and electrical performance; silver coatings offer optimal electrical and thermal conductivity; copper coatings are cost-effective and have good diffusion properties; nickel coatings have high hardness, good wear resistance, and excellent lattice compatibility with stainless steel substrates; alloy coatings can achieve customized performance through composition adjustments. The active metal coating exhibits excellent lattice compatibility and atomic affinity with the metal substrate.

[0047] Furthermore, the thickness of the active metal coating can be 5-20 μm. Within this thickness range, the active metal coating provides sufficient atoms for interfacial diffusion without causing prolonged bonding time or increased interfacial brittleness due to excessive thickness. In this invention, the active metal coating serves as an intermediate transition layer for pure diffusion bonding, requiring sufficient thickness to provide a continuous source of atomic diffusion.

[0048] In this embodiment of the invention, the step of placing the stacked and aligned overall structure in a vacuum environment for heating and applying pressure to perform diffusion bonding may specifically include: The stacked and aligned integral structure is placed in a vacuum autoclave, and a vacuum is evacuated. The vacuum autoclave has a controllable vacuum system, heating system, and pressurization system. The integral structure is placed on the worktable of the vacuum autoclave, the furnace door is closed, and the vacuum system is activated to perform the vacuum evacuation operation.

[0049] Then, the temperature is raised to the preset bonding temperature and vertical pressure is applied for heat and pressure maintenance. After reaching the preset vacuum level, the heating system is activated to raise the furnace temperature to the preset bonding temperature at a certain heating rate. At the same time or slightly afterward, the pressurization system is activated to apply vertical pressure to the top of the overall structure through the upper pressure head. When both temperature and pressure reach the preset values, the heat and pressure maintenance stage begins.

[0050] After cooling, the various metal substrates 100 are bonded together to form a single 3D printing head structure. After the heat preservation and pressure holding process is completed, the heating system is turned off, and the furnace temperature is slowly cooled to room temperature while maintaining pressure. After cooling, the furnace door is opened, the bonded integral structure is removed, and the positioning fixture is disassembled, thus obtaining the 3D printing head structure in which the various metal substrates 100 are metallurgically bonded together.

[0051] Under the above conditions, the four sub-steps of vacuuming, heating and pressurizing, holding at temperature and pressure, and cooling are executed sequentially in a specific order, forming a complete vacuum diffusion bonding process. The vacuuming step provides a pure interface environment for subsequent heating and pressurizing; simultaneous heating and pressurizing avoids interface oxidation or substrate thermal deformation caused by heating before pressurizing; holding at temperature and pressure provides sufficient time for atomic diffusion and recrystallization; and holding pressure during cooling ensures that the interface remains in close contact during cooling and shrinkage, preventing interface separation.

[0052] Furthermore, the vacuum level of the vacuum environment can be 1×10^(-5)-1×10^(-1) Pa; the heating temperature can be 800-1500°C; the applied pressure can be 0.1-1 MPa; and the holding time can be 1-3 hours. By controlling these four key parameters—vacuum level, temperature, pressure, and time—high-quality vacuum diffusion bonding is achieved. The vacuum environment eliminates air between interfaces, preventing oxidation and promoting atomic diffusion; the bonding temperature is much lower than the substrate melting point, avoiding damage to the substrate's properties at high temperatures; the appropriate pressure ensures interface contact without causing substrate deformation; and the reasonable holding time ensures sufficient diffusion bonding without affecting production efficiency.

[0053] In one optional embodiment, the positioning fixture may include a base, at least two positioning posts vertically disposed on the base, and a pressure plate slidable along the axial direction of the positioning posts. The fastening mechanism includes a locking member disposed above the pressure plate, which applies a vertical preload to each metal substrate 100 by tightening the locking member. Specifically, the base of the positioning fixture may be a flat plate structure. The positioning posts are vertically fixed on the base, and the number of positioning posts is at least two (preferably four, distributed near the four corners of the substrate) to ensure the positioning accuracy of each metal substrate 100 in the horizontal plane. The diameter of the positioning posts is determined according to the diameter of the positioning holes 110, and the positioning posts and positioning holes 110 are clearance fits, with the clearance controlled within 10 μm.

[0054] The pressure plate is a flat plate with through holes corresponding to the positions of the positioning posts. The pressure plate is fitted onto the positioning posts through the through holes and can slide freely along the axial direction of the positioning posts. A locking element is located above the pressure plate and can be a lock nut or a quick-release clamp. When a lock nut is used, the upper end of the positioning post has an external thread. The lock nut engages with this external thread. By tightening the lock nut, the pressure plate moves downward, applying a vertical preload to each metal substrate 100. When a quick-release clamp is used, the quick-release clamp is fixed to the top of the positioning post. By operating the handle of the quick-release clamp, the clamp's pressure head moves downward, pushing the pressure plate to apply a preload to each metal substrate 100.

[0055] To ensure a uniform distribution of preload, an elastic gasket can be provided between the pressure plate and the uppermost metal substrate 100 to buffer the pressure and compensate for the thickness tolerance between the substrates.

[0056] The specific structural design of the positioning fixture makes the stacking and alignment of the multilayer metal substrates 100 simple, efficient, and precise. The base provides a flat support reference surface, ensuring the flatness of the bottom surface of the overall structure after stacking; the precise fit between the positioning pins and positioning holes 110 ensures the precise alignment of each substrate layer in the horizontal plane; the sliding pressure plate can adapt to stacks of different total thicknesses; the locking element can apply a uniform and controllable vertical preload to each substrate layer, ensuring that each substrate layer is tightly bonded and has no relative displacement before entering the hot press furnace, providing uniform interface contact conditions for subsequent diffusion bonding.

[0057] In this embodiment of the invention, the thickness of each metal substrate 100 layer is 0.05 mm to 0.5 mm. At this time, each metal substrate 100 layer adopts a differentiated thickness design. For example, the nozzle plate can use multiple metal substrates with a thickness of 0.05 mm to 0.15 mm, the flow divider plate can use multiple metal substrates with a thickness of 0.1 mm to 0.3 mm, and the base can use a metal substrate with a thickness of 0.2 mm to 0.5 mm. Designing metal substrates of different thicknesses for different functional modules ensures that different functional areas of the 3D printing head achieve optimal performance. Furthermore, limiting the thickness range of the metal substrate to 0.05-0.5 mm ensures both the structural stability of each substrate layer during the chemical etching process (too thin a substrate is prone to deformation) and the matching of heat capacity during vacuum diffusion bonding (too thick a substrate results in large differences in heat capacity, affecting bonding uniformity).

[0058] Based on the 3D printing device forming method described in the embodiments of the present invention, the present invention also discloses a 3D printing head, which is manufactured using the 3D printing device forming method described in any of the above embodiments. Specifically, the 3D printing head includes a multi-layer metal substrate 100 structure formed integrally by metallurgical bonding. Each metal substrate 100 includes, but is not limited to, different functional layers such as nozzle plates, flow dividers, and bases stacked sequentially, and there is a continuous and gapless atomic-level metallurgical bonding interface between each metal substrate 100. The microchannel through-holes 120 on each metal substrate 100 are aligned and connected to each other to form an internal microchannel—that is, a complete ink flow path from the ink supply channel of the base through the flow divider channel of the flow divider to the nozzle array of the nozzle plate.

[0059] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for forming a 3D printing device, characterized in that, include: Prepare each layer of metal substrate (100). Positioning holes (110) and microchannel through holes (120) are respectively processed on each metal substrate (100). An active metal plating layer is formed on the bonding surface of each of the metal substrates (100); All the processed metal substrates (100) are stacked on the positioning fixture in a preset order, so that the microchannel vias (120) on each metal substrate (100) are aligned and connected to each other to form internal microchannels. The pre-tightening force is applied by the fastening mechanism on the positioning fixture to make the metal substrates (100) of each layer fit together tightly; The stacked and aligned overall structure is placed in a vacuum environment, heated and pressure is applied for diffusion bonding, so that the metal substrates (100) of each layer are combined to form an integral 3D printing device.

2. The 3D printing device forming method according to claim 1, characterized in that, In the process of machining positioning holes (110) and microchannel through holes (120) on each layer of metal substrate (100), the machining of the microchannel through holes (120) adopts a combined machining method: first, a guide hole is pre-made on the metal substrate (100) using laser machining process, and then, based on the guide hole, the final forming of the microchannel through hole (120) is completed by chemical etching process.

3. The 3D printing device forming method according to claim 1, characterized in that, After machining positioning holes (110) and microchannel vias (120) on each layer of the metal substrate (100), the method further includes cleaning each layer of the metal substrate (100) with ultrapure water.

4. The 3D printing device forming method according to claim 1, characterized in that, The active metal coating is made of gold, silver, copper, nickel, or an alloy thereof.

5. The 3D printing device forming method according to claim 1, characterized in that, The thickness of the active metal coating is 5-20 μm.

6. The 3D printing device forming method according to claim 1, characterized in that, The step of placing the stacked and aligned overall structure in a vacuum environment, heating it, and applying pressure to perform diffusion bonding specifically includes: The stacked and aligned overall structure is placed in a vacuum hot press furnace and a vacuum is drawn. Then, the temperature is raised to the preset bonding temperature and vertical pressure is applied to maintain the temperature and pressure. After cooling, the metal substrates (100) of each layer are bonded together to form an integral structure.

7. The 3D printing device forming method according to claim 6, characterized in that, The vacuum level of the vacuum environment is 1×10^(-5)-1×10^(-1) Pa; the heating temperature is 800-1500°C; the applied pressure is 0.1-1 MPa; and the heat and pressure holding time is 1-3 hours.

8. The 3D printing device forming method according to claim 1, characterized in that, The positioning fixture includes a base, at least two positioning posts vertically arranged on the base, and a pressure plate that can slide along the axial direction of the positioning posts. The fastening mechanism includes a locking member arranged above the pressure plate. By tightening the locking member, a preload force in the vertical direction is applied to each layer of the metal substrate (100).

9. The 3D printing device forming method according to claim 1, characterized in that, The thickness of each layer of the metal substrate (100) is 0.05 mm to 0.5 mm.

10. A 3D printing head, characterized in that, It is manufactured using the molding method of the 3D printing apparatus as described in any one of claims 1 to 9.

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