Telescopic infusion tube for crucible lifting printing and metal printing method

Abstract

The invention provides a telescopic liquid conveying pipe for crucible lifting printing and a metal printing method, and mainly relates to the technical field of liquid metal printing equipment. A telescopic liquid conveying pipe for crucible lifting printing comprises a fixing assembly, a telescopic conveying assembly, a buffering assembly, a connecting assembly and a printing crucible. The printing crucible is a cavity defined by a crucible right side plate, a crucible left side plate, a crucible front plate and a crucible rear plate, and the bottom of the printing crucible is sealed through a crucible bottom plate. The fixing assembly comprises a fixing flange barrel, a calcium silicate protective sleeve and a sectioning clamping sleeve and is used for being fixedly connected with an equipment body. The telescopic conveying assembly is composed of a small pipe unit and a large pipe unit, sliding stretching is achieved through step matching, and heat preservation cotton is arranged on the matching face for sealing. The buffer assembly comprises a buffer box and a filter buffer plate, is fixed in the crucible cavity, and can be used for filtering, stabilizing flow and preventing overflow; the connecting assembly comprises a nozzle plate, a pressing plate and a heating pipe, and nozzles are prevented from being blocked. The device can stretch and retract synchronously along with lifting of the crucible, stable approaching conveying of liquid metal is guaranteed, and the printing success rate and the printing piece quality are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of liquid metal printing equipment, in particular to a telescopic liquid conveying pipe for lifting printing of a crucible and a metal printing method. BACKGROUND

[0002] In the field of liquid metal printing, especially when using the melt impact printing process, it is necessary to stably convey liquid metal (such as aluminum liquid) from the conveying source to the printing crucible through the liquid conveying pipe. At the same time, in order to ensure the printing quality, the liquid conveying pipe needs to be kept close to the crucible to reduce the disturbance and oxidation of the liquid metal during the conveying process.

[0003] In the prior art, the scheme for conveying liquid metal with a drop difference usually adopts a lifting pipe or a fixed pipe made of other materials. The lifting pipe is usually suitable for low-pressure casting process, and its length is fixed and cannot be adjusted according to the lifting action of the crucible during the printing process. Other fixed pipes such as stainless steel pipes and ceramic pipes have certain heat resistance, but they also do not have telescopic ability and cannot meet the close conveying requirements of the melt impact printing. In addition, the existing pipes have insufficient heat insulation and sealing performance, which can easily cause the temperature of the liquid metal to decrease during the conveying process, resulting in local solidification, and even blockage of the pipe. Moreover, the pipes lack effective filtering and flow stabilizing structures, which cannot remove impurity particles in the metal liquid and cannot slow down the flow speed of the metal liquid, further exacerbating the quality problems of the printed parts. SUMMARY

[0004] To solve the problems of the prior art, the present application provides a telescopic liquid conveying pipe for lifting printing of a crucible, which can realize telescopic adjustment according to the lifting of the crucible and ensure stable close conveying of the liquid metal.

[0005] To achieve the above-mentioned purpose, the present application realizes the following technical scheme: A telescopic liquid conveying pipe for lifting printing of a crucible, comprising a fixed assembly, a telescopic conveying assembly, a buffer assembly, a connecting assembly and a printing crucible; the printing crucible comprises a crucible right side plate, a crucible left side plate and a crucible front and rear plate, and the crucible right side plate, the crucible left side plate and the crucible front and rear plate form a crucible cavity; the fixed assembly is used to connect with the equipment main body to realize overall structure fixation, the telescopic conveying assembly is connected with the fixed assembly and can slide and telescope relatively, the buffer assembly cooperates with the telescopic conveying assembly and is fixed in the cavity of the printing crucible, and the connecting assembly is used for assembly and fixation of the buffer assembly and the printing crucible.

[0006] Further, the fixing assembly comprises a fixing flange barrel, a calcium silicate sheath and a calcium silicate split sleeve; the calcium silicate sheath is arranged inside the fixing flange barrel, the calcium silicate split sleeve is embedded in the calcium silicate sheath, and the fixing flange barrel is connected with the equipment body. The fixing flange barrel serves as the installation basis of the overall structure, and realizes the fixed positioning of the liquid conveying pipe through the connection with the equipment body; the calcium silicate sheath has good heat insulation performance, and can reduce the heat loss in the liquid metal conveying process; the calcium silicate split sleeve is used for the assembly and fixation of the subsequent telescopic conveying assembly.

[0007] Further, the telescopic conveying assembly comprises a small pipe unit and a large pipe unit; the small pipe unit comprises a small pipe lining and a small pipe outer sheath, the top end of the small pipe lining is stepped, the calcium silicate split sleeve is connected with the stepped end of the small pipe lining, and the upper end of the small pipe outer sheath is provided with a flange edge, which is connected with the lower bottom of the fixing flange barrel; the large pipe unit comprises a large pipe outer sheath and a large pipe lining, the upper end of the large pipe lining is provided with a step, the step is connected with the lower end flange of the small pipe outer sheath, and heat insulation cotton is arranged at the connecting surface to realize telescopic sealing, and the large pipe outer sheath is arranged outside the large pipe lining.

[0008] Further, the large pipe outer sheath is used for providing protection and reinforcement for the large pipe lining, and the small pipe outer sheath is used for bearing the weight of the overall liquid conveying pipe. The small pipe lining and the large pipe lining constitute the conveying channel of the liquid metal, and are connected through the step connection of the small pipe outer sheath and the large pipe lining. The heat insulation cotton at the connecting surface can not only ensure the sealing property in the telescopic process, prevent the leakage of liquid metal and the entry of air, but also further enhance the heat insulation effect; the flange edge of the small pipe outer sheath is connected with the clamping structure of the fixing flange barrel, so that the weight of the overall liquid conveying pipe is transmitted to the fixing assembly, and the structural stability is ensured; and the large pipe outer sheath forms a wrapping protection for the large pipe lining, so as to avoid damage of the large pipe lining due to external force impact or liquid metal impact during the telescopic and use processes.

[0009] Further, the buffer assembly comprises a buffer box and a filter buffer plate; the buffer box is matched with the gap of the large pipe lining, the filter buffer plate is arranged in the buffer box, the bottom of the buffer box is provided with a liquid passing hole, the bottom of the side edge end face is provided with an overflow groove, and the buffer box is fixed in the cavity surrounded by the crucible right side plate, the crucible left side plate and the crucible front and rear plate. The buffer box as a transition structure before the liquid metal enters the crucible is matched with the gap of the large pipe lining to adapt to the sliding action of the telescopic conveying assembly; the filter buffer plate can filter the conveyed liquid metal to remove impurity particles therein, and slow down the flow speed of the liquid metal to avoid stirring caused by too high flow speed; the bottom liquid passing hole is used for guiding the buffered liquid metal into the crucible cavity, and the side edge overflow groove can play an overflow buffering role when the conveying amount of the liquid metal is too large to prevent the metal liquid from overflowing; and the cavity surrounded by the crucible right side plate, the crucible left side plate and the crucible front and rear plate provides a stable installation space and a protection boundary for the buffer box.

[0010] Further, the connecting assembly comprises a nozzle plate, a nozzle pressing plate and a crucible bottom plate; the crucible bottom plate is connected with the crucible right side plate, the crucible left side plate and the crucible front and rear plate to close the bottom of the printing crucible, the nozzle plate is installed in the crucible bottom plate, the nozzle pressing plate is connected with the nozzle plate to realize compression and fixation, and the nozzle pressing plate is provided with a heating pipe. The crucible bottom plate, the crucible right side plate, the crucible left side plate and the crucible front and rear plate jointly constitute a complete printing crucible structure to provide a containing space for the liquid metal; the nozzle plate as an outlet structure for the liquid metal entering the printing area guarantees assembly sealing through compression and fixation of the nozzle pressing plate; and the heating pipe can heat and keep warm the nozzle plate to prevent the liquid metal from solidifying and blocking at the nozzle due to temperature reduction.

[0011] Compared with the prior art, the beneficial effects of the present application are: 1. Through the cooperative matching of the fixing assembly, the telescopic conveying assembly, the buffer assembly, the connecting assembly and the printing crucible, the device not only realizes the telescopic function of the liquid conveying pipe, can adjust the length synchronously with the lifting action of the crucible, accurately meets the close conveying requirement of the melt impact printing, but also provides a stable containing and protection space for the liquid metal conveying and printing process through the cavity structure of the printing crucible, solves the problem that the traditional fixed pipe cannot adapt to the lifting of the crucible and lacks integrated protection.

[0012] 2. The small pipe unit and the large pipe unit of the telescopic conveying assembly are connected through step matching, the heat preservation cotton of the matching surface has the functions of telescopic sealing and heat insulation, the small pipe outer guard plate and the large pipe outer guard plate respectively provide bearing and reinforcing effects for the lining structure, effectively solve the defect of insufficient strength of the traditional heat insulation material, and ensure the stability and reliability of the telescopic action.

[0013] 3. The filter buffer plate of the buffer assembly can remove impurities and stabilize the flow of liquid metal. The overflow groove design of the buffer box further improves the safety of the conveying process, significantly reduces the disturbance of liquid metal, and reduces the risk of oxidation and inclusion. Moreover, the buffer box is fixed in the cavity of the printed crucible and forms a linkage with the crucible structure to ensure the continuous stability of the close-range conveying state.

[0014] 4. In the connecting components, the cooperation between the crucible bottom plate and the crucible side plate achieves complete sealing of the printing crucible. The design of the nozzle plate and heating tube can effectively prevent nozzle clogging and ensure the continuity of the printing process. The overall structure provides stable proximity control and smooth delivery for liquid metal crucible printing, greatly improving the printing success rate and the quality of printed parts. Attached Figure Description

[0015] Figure 1 Layout diagram of the main body for printing the liquid metal crucible; Figure 2 A partial cross-sectional view of the main body of the liquid metal crucible printing arrangement; Figure 3 This is a diagram showing the overall layout of the telescopic infusion tubing.

[0016] The following are the labels shown in the attached diagram: 1. Fixed flange barrel; 2. Calcium silicate sleeve; 3. Calcium silicate split sleeve; 4. Small tube inner lining; 5. Small tube outer protective plate; 6. Large tube outer protective plate; 7. Large tube inner lining; 8. Buffer box; 9. Right side plate of crucible; 10. Left side plate of crucible; 11. Front and rear plates of crucible; 12. Filter buffer plate; 13. Crucible bottom plate; 14. Nozzle pressure plate; 15. Nozzle plate. Detailed Implementation

[0017] The present invention will be further described in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined in this application.

[0018] Example: A telescopic infusion tube for crucible lifting and printing The components include: a fixed flange barrel 1, a calcium silicate sleeve 2, a calcium silicate split sleeve 3, a small tube inner liner 4, a small tube outer protective plate 5, a large tube outer protective plate 6, a large tube inner liner 7, a buffer box 8, a filter buffer plate 12, a nozzle plate 15, a nozzle pressure plate 14, and a printing crucible composed of a right side plate 9, a left side plate 10, front and rear plates 11, and a bottom plate 13.

[0019] Assembly of the printing crucible: The crucible bottom plate 13 is connected and fixed to the crucible right side plate 9, the crucible left side plate 10 and the crucible front and rear plates 11 to form a closed crucible cavity, which serves as the basic structure for containing and printing liquid metal.

[0020] The assembly process of the fixed component is as follows: insert the calcium silicate sleeve 2 into the fixed flange barrel 1, then insert the calcium silicate split sleeve 3 into the preset position of the calcium silicate sleeve 2, and finally connect and fix the fixed flange barrel 1 to the main body of the printing equipment.

[0021] Assembly of the telescopic conveyor assembly: Align the stepped end of the top of the inner tube liner 4 with the calcium silicate split sleeve 3, and fix the inner tube liner 4 in the calcium silicate sleeve 2 by snap-fit; put the outer tube outer protective plate 5 on the outside of the inner tube liner 4, so that the flange edge of its upper end is snapped into the lower bottom of the fixed flange barrel 1 to fix the inner tube unit; align the step at the upper end of the inner tube liner 7 with the flange at the lower end of the outer tube outer protective plate 5, and add insulation cotton at the mating surface to complete the connection; finally, put the outer tube outer protective plate 6 on the outside of the inner tube liner 7 to complete the assembly of the telescopic conveyor assembly.

[0022] Assembly of the buffer assembly and connecting assembly: Install the filter buffer plate 12 into the buffer box 8, connect the buffer box 8 with the inner liner of the large tube 7 with clearance fit, and fix the buffer box 8 in the cavity enclosed by the right side plate 9, the left side plate 10 and the front and rear plates 11 of the crucible; install the nozzle plate 15 into the preset mounting hole of the crucible bottom plate 13, and press it firmly with the nozzle pressure plate 14 to ensure that the heating tube inside the nozzle pressure plate 14 is in the correct position.

[0023] The working process of this embodiment is as follows: The purified aluminum liquid is transported to the printing equipment through a chute. The aluminum passage hole at the bottom of the chute is connected to the calcium silicate sheath 2. The flow control switch at the aluminum passage hole of the chute adjusts the amount of aluminum to control the conveying speed. The aluminum liquid first enters the inner liner of the small tube 4, is transported to the inner liner of the large tube 7 through the small tube unit, and then flows into the buffer tank 8. In the buffer tank 8, the filter buffer plate 12 filters and removes impurities from the aluminum liquid and slows down its flow speed. The buffered aluminum liquid enters the cavity of the printing crucible through the liquid passage hole at the bottom of the buffer tank 8. If the amount of aluminum liquid transported is too large, the excess aluminum liquid is discharged through the side overflow trough to prevent overflow.

[0024] The crucible is initially positioned at a high level, and printing begins after it descends to the initial printing height. As the height of the printed part gradually increases, the lifting mechanism slowly raises the printing crucible, including the right side plate 9, left side plate 10, front and rear plates 11, and bottom plate 13. Simultaneously, the crucible moves the buffer box 8 upward, which in turn pushes the inner liner 7 of the large tube to slide upward along the lower flange of the outer protective plate 5 of the small tube. Since the inner liner 4 of the small tube is fixed by the calcium silicate split sleeve 3, and the outer protective plate 5 of the small tube is fixed by the fixed flange barrel 1, relative sliding expansion and contraction occurs between the large tube unit and the small tube unit, always keeping the buffer box 8 close to the crucible cavity until the entire printing process is completed.

[0025] Based on the above-mentioned device, a metal printing method for a telescopic infusion tube used for crucible lifting and printing includes the following steps: Step 1: Equipment Assembly and Debugging Printing crucible assembly: The crucible base plate 13 is connected and fixed to the crucible right side plate 9, crucible left side plate 10, and crucible front and rear plates 11 by welding. The welds must be non-destructive tested to ensure that there are no defects such as pores or cracks, forming a closed crucible cavity. This step is to provide a stable and sealed space for the subsequent containment and printing of liquid metal. Non-destructive testing of the welds is crucial to ensuring that the crucible does not leak or get damaged when bearing the weight of the liquid metal and the pressure during the printing process.

[0026] Fixed component assembly: Assemble components with a thickness of 50-80mm and a thermal conductivity ≤0.06W / (m²). The calcium silicate sleeve 2 (K) is inserted into the fixed flange barrel 1. Then, the calcium silicate segmented sleeve 3, composed of 2-4 arc-shaped segments, is inserted into the preset position of the calcium silicate sleeve 2. The joints are filled with high-temperature resistant sealant with a temperature resistance of not less than 1200℃. Finally, the fixed flange barrel 1 is fixed to the main body of the printing equipment with bolts, and the bolt tightening torque meets the equipment installation specifications. The low thermal conductivity of the calcium silicate sleeve 2 can effectively reduce heat loss of liquid metal during transportation. The use of high-temperature resistant sealant can prevent heat loss from the joints and avoid liquid metal leakage. The bolt connection and the adherence to the tightening torque specifications are important steps to ensure the stability of the connection between the fixed components and the main body of the equipment.

[0027] Telescopic conveyor assembly: Align the top stepped end of the small tube liner 4 (made of silicon nitride ceramic with an inner wall roughness Ra≤0.8μm) with the calcium silicate split sleeve 3 and fix it by snap-fit; fit the small tube outer protective plate 5 (8-12mm thick, made of 304 stainless steel) on the outside of the small tube liner 4, and snap its upper flange edge with the bottom of the fixed flange barrel 1 to ensure that the flange edge bearing strength meets the requirement of ≥20MPa; fit the upper stepped end of the large tube liner 7 (also made of silicon nitride ceramic) with the lower flange of the small tube outer protective plate 5, and add 15-25mm thick alumina ceramic fiber cotton insulation cotton with a compression rebound rate of ≥85% at the mating surface; finally, fit the large tube outer protective plate 6 (8-12mm thick, made of 304 stainless steel with an impact strength of ≥20J / cm²) on the outside of the large tube liner 7. Silicon nitride ceramic material has good high temperature resistance and corrosion resistance. Its low inner wall roughness can reduce the flow resistance of liquid metal during transportation and ensure smooth transportation. The outer protective plate made of 304 stainless steel can provide good protection and load-bearing capacity for the inner lining, meeting the requirements of load-bearing strength and impact resistance. The high compression resilience of alumina ceramic fiber cotton insulation cotton can not only ensure the sealing performance during expansion and contraction, but also further enhance the heat insulation effect.

[0028] Assembly of buffer and connecting components: Install the porous ceramic filter buffer plate 12 with a pore size of 0.1-0.5mm and a porosity of 30%-50% into the heat-resistant cast steel buffer box 8 with a temperature resistance upper limit of not less than 800℃; connect the buffer box 8 and the inner lining of the large tube 7 with a gap of 0.5-1.5mm, and fix the buffer box 8 in the crucible cavity; install the hard alloy nozzle plate 15 with a hardness ≥HRC60 into the preset mounting hole of the crucible bottom plate 13, and use 4-6 bolts of M8-M12 to connect and tighten the nozzle pressure plate 14 and the nozzle plate 15, ensuring that the stainless steel electric heating tube with a power of 500-1000W and a heating temperature range of 200-600℃ in the nozzle pressure plate 14 is accurately positioned, and fill the space between the heating tube and the nozzle pressure plate 14 with magnesium oxide insulating material to ensure that the insulation resistance is ≥100MΩ. The porous ceramic filter buffer plate 12 can effectively filter impurities in liquid metal and also plays a role in stabilizing the flow; the heat-resistant cast steel buffer box 8 can withstand the high temperature of liquid metal, and the gap fit with the inner lining of the large pipe facilitates the adaptation to expansion and contraction; the high-hardness hard alloy nozzle plate 15 can ensure the wear resistance and stability of the nozzle during long-term use; the setting of the heating tube can prevent liquid metal from solidifying and clogging at the nozzle; and the magnesium oxide insulation material ensures the electrical safety of the heating process.

[0029] Commissioning: Start the equipment and check the sliding and telescopic performance of the telescopic conveyor assembly to ensure that the large tube unit slides smoothly relative to the small tube unit without any jamming. Turn on the heating tube inside the nozzle pressure plate 14 and check whether the heating temperature can be stably maintained within the set range. At the same time, check the sealing of each connection to ensure there are no leaks. The commissioning stage is an inspection of the equipment assembly quality. The smoothness of the sliding and telescopic performance directly affects the synchronous adjustment of the delivery tube when the crucible is raised and lowered. The stability of the heating temperature and the sealing of the connection are key to ensuring the smooth progress of the printing process and the printing quality.

[0030] Step Two: Liquid Metal Preparation and Transfer Metal smelting: The metal to be printed (such as aluminum ingot) is placed into a smelting furnace and heated and smelted according to the metal material smelting process requirements. The smelting temperature is determined according to the type of metal. For example, the smelting temperature of aluminum liquid is controlled at 660-700℃. During the smelting process, refining agents are added to remove impurities and ensure the purity of the molten metal. If the metal to be printed is an aluminum alloy, an Al-Ti-B grain refiner needs to be added during smelting, at a rate of 0.1%-0.3% of the aluminum alloy mass, to refine the grains. Different metals have different smelting temperatures. Strictly controlling the smelting temperature is a prerequisite for ensuring that the metal is fully melted and that excessive oxidation or other adverse chemical reactions do not occur. The addition of refining agents can remove impurities in the molten metal and improve its purity. For aluminum alloys, the addition of Al-Ti-B grain refiners can refine the grains and improve the mechanical properties of the printed parts.

[0031] Metal molten metal transport: The purified metal molten metal is transported to the printing equipment through a chute. The aluminum through-hole at the bottom of the chute mates with the calcium silicate sleeve 2. The flow control switch at the aluminum through-hole of the chute is adjusted to control the metal molten metal transport speed at 1-3 L / min. The metal molten metal sequentially enters the inner lining of the small tube 4, the inner lining of the large tube 7, and finally flows into the buffer tank 8. Controlling the metal molten metal transport speed within a reasonable range can avoid excessive disturbance and oxidation of the liquid metal during transport due to excessive flow rate, or affect printing efficiency due to insufficient flow rate. The mating of the chute and the calcium silicate sleeve 2 ensures smooth and sealed metal molten metal transport and prevents metal molten metal leakage.

[0032] Step 3: Coordinating Buffering and Flow Stabilization with Crucible Lifting Buffering and Filtration: After the molten metal enters the buffer tank 8, it is filtered and impurities are removed by the filter buffer plate 12, which also slows down the flow rate to 0.5-1 m / s. The buffered molten metal then enters the crucible cavity through 3-5 evenly distributed liquid passage holes with a diameter of 10-20 mm at the bottom of the buffer tank 8. If the molten metal flow is too large, the excess molten metal is discharged through an overflow trough with a width of 8-15 mm and a depth of 5-10 mm on the side of the buffer tank 8 to prevent overflow. The filtering and flow stabilizing effects of the filter buffer plate 12 further improve the purity and stability of the molten metal entering the crucible cavity, reducing interference with the printing process. The size, number, and even distribution of the liquid passage holes ensure that the molten metal enters the crucible cavity evenly and stably. The overflow trough is a safety measure to prevent overflow of the crucible cavity due to abnormal molten metal flow, which would affect the normal operation of the equipment and the printing quality.

[0033] Crucible lifting control: Initially, the lifting mechanism is used to position the crucible at a high level, then lowers it to the starting printing height at a speed of 5-10 mm / s. After printing begins, as the height of the printed part increases, the lifting mechanism slowly raises the printing crucible at a speed of 2-5 mm / s. Simultaneously, the crucible moves the buffer box 8 upwards, pushing the inner liner 7 of the large tube upwards along the lower flange of the outer protective plate 5 of the small tube. The large and small tube units slide and extend relative to each other, maintaining the buffer box 8 close to the crucible cavity at a distance controlled within 1-3 mm. During the crucible lifting process, a displacement sensor monitors the crucible position in real time, with displacement accuracy controlled within ±0.1 mm, ensuring precise matching between the lifting action and the printing rhythm. Reasonable control of the crucible's lifting and lowering speed can ensure the continuity and stability of the printing process, while avoiding equipment vibration or adverse effects on the printed parts due to excessive speed. Maintaining the buffer box 8 in close proximity to the crucible cavity can reduce disturbance and oxidation of the liquid metal during its entry into the crucible cavity, thereby improving printing quality. Real-time monitoring and high-precision control by the displacement sensor are key to achieving precise coordination between the lifting and lowering actions and the printing rhythm, ensuring that the dimensional accuracy of the printed parts meets the requirements.

[0034] Step 4: Monitoring and Ending of the Printing Process Process Monitoring: During printing, the temperature of the molten metal, the conveying speed, the crucible lifting speed, and the temperature of the nozzle plate 15 are monitored in real time. The temperature fluctuation of the molten metal is controlled within ±10℃, and the temperature of the nozzle plate 15 is maintained within ±5℃ of the set value through the heating tube. If any parameter abnormality occurs, the equipment automatically alarms and pauses printing, resuming only after the fault is resolved. An infrared thermometer is used to monitor the temperature of the molten metal with an accuracy of ±1℃, and a flow meter is used to monitor the conveying speed of the molten metal with a flow accuracy of ±0.1L / min, ensuring the accuracy of parameter monitoring during the printing process. Real-time monitoring of various parameters and control within a reasonable fluctuation range is an important means to ensure the stability of the printing process and the quality of the printed parts; high-precision monitoring equipment can provide accurate basis for parameter adjustment, promptly detect and handle abnormalities, and avoid printing failures or defects in printed parts due to parameter abnormalities.

[0035] Printing Completion: Once the printed part reaches the preset size, first turn off the chute flow switch to stop the molten metal delivery. After the remaining molten metal in the crucible has finished printing, turn off the nozzle heating tube, control the lifting mechanism to lower the crucible to the initial position, remove the printed part, and clean and maintain the equipment. Remove any residual metal slag from the delivery pipes and crucible, and check the integrity of all components to prepare for the next print. This post-printing procedure ensures the normal service life of the equipment, provides a good equipment condition for the next print, avoids residual metal slag affecting subsequent printing processes and print quality, and allows for timely detection and repair of potential equipment problems.

[0036] In step 1.3, after the telescopic conveying assembly is assembled, an airtightness test is required. Compressed air at 0.3-0.5 MPa is introduced into the infusion tube and held at that pressure for 30 minutes. The pressure drop should be ≤0.02 MPa to ensure the insulation cotton's sealing performance meets the requirements. In step 1.4, after the buffer tank 8 is fixed, a levelness test is required. The levelness deviation should be ≤0.1 mm / m to prevent uneven flow of the molten metal within the buffer tank 8. The airtightness test is a crucial inspection step to ensure that the infusion tube does not leak during the transport of molten metal. The levelness test ensures that the molten metal flows uniformly within the buffer tank 8, avoiding uneven flow that could affect the buffering and filtration effects, and consequently, the printing quality.

[0037] In explaining this invention, it should be noted that the terms indicating location are used only for ease of description and understanding, and are not intended to limit the installation location of specific technical features. Other possible installation methods are not excluded.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A telescopic infusion tube for crucible lifting and printing, characterized in that, The device includes a fixing component, a telescopic conveying component, a buffer component, a connecting component, and a printing crucible. The printing crucible includes a right side plate (9), a left side plate (10), and front and rear plates (11). The right side plate (9), the left side plate (10), and the front and rear plates (11) together form a crucible cavity. The fixing component is used to connect with the main body of the device to achieve overall structural fixation. The telescopic conveying component is connected to the fixing component and can slide and extend relative to it. The buffer component cooperates with the telescopic conveying component and is fixed in the cavity of the printing crucible. The connecting component is used to assemble and fix the buffer component and the printing crucible.

2. The telescopic infusion tube for crucible lifting and printing according to claim 1, characterized in that, The fixing assembly includes a fixing flange barrel (1), a calcium silicate sleeve (2), and a calcium silicate split sleeve (3); the calcium silicate sleeve (2) is located inside the fixing flange barrel (1), the calcium silicate split sleeve (3) is embedded in the calcium silicate sleeve (2), and the fixing flange barrel (1) is connected to the main body of the equipment.

3. The telescopic infusion tube for crucible lifting and printing according to claim 2, characterized in that, The telescopic conveying assembly includes a small tube unit and a large tube unit; the small tube unit includes a small tube liner (4) and a small tube outer protective plate (5), the top of the small tube liner (4) is stepped, the calcium silicate split sleeve (3) is engaged with the stepped end of the small tube liner (4), the upper end of the small tube outer protective plate (5) is provided with a flange edge, and the flange edge is engaged with the lower bottom of the fixed flange barrel (1); the large tube unit includes a large tube outer protective plate (6) and a large tube liner (7), the upper end of the large tube liner (7) is provided with a step, the step is engaged with the lower flange of the small tube outer protective plate (5), and the mating surface is provided with heat insulation cotton to achieve telescopic sealing, and the large tube outer protective plate (6) is sleeved on the outside of the large tube liner (7).

4. The telescopic infusion tube for crucible lifting and printing according to claim 3, characterized in that, The outer protective plate (6) of the large tube is used to provide protection and reinforcement for the inner lining (7) of the large tube, and the outer protective plate (5) of the small tube is used to bear the weight of the entire infusion tube.

5. A telescopic infusion tube for crucible lifting and printing according to claim 4, characterized in that the buffer assembly includes a buffer box (8) and a filter buffer plate (12); the buffer box (8) is fitted with the inner lining (7) of the large tube with a clearance, the filter buffer plate (12) is disposed in the buffer box (8), the bottom of the buffer box (8) has a liquid passage hole, the bottom of the side end face has an overflow groove, and the buffer box (8) is fixed in the cavity enclosed by the right side plate (9) of the crucible, the left side plate (10) of the crucible and the front and rear plates (11) of the crucible.

6. A telescopic infusion tube for crucible lifting and printing according to claim 5, characterized in that the connecting assembly includes a nozzle plate (15), a nozzle pressure plate (14), and a crucible bottom plate (13); the crucible bottom plate (13) is connected to the crucible right side plate (9), the crucible left side plate (10), and the crucible front and rear plates (11) to seal the bottom of the printing crucible; the nozzle plate (15) is installed in the crucible bottom plate (13); the nozzle pressure plate (14) is connected to the nozzle plate (15) to achieve clamping and fixing; and a heating tube is provided inside the nozzle pressure plate (14).

7. A metal printing method for a telescopic infusion tube for crucible lifting printing according to any one of claims 1-6, characterized in that it includes the following steps: Step 1: Equipment Assembly and Debugging 1.1 Printing crucible assembly: The crucible bottom plate (13) is connected and fixed to the crucible right side plate (9), crucible left side plate (10) and crucible front and rear plates (11) by welding. The welds need to be non-destructive tested to ensure that there are no defects such as pores and cracks, forming a closed crucible cavity; 1.2 Assembly of fixed components: Assemble components with a thickness of 50-80mm and a thermal conductivity ≤0.06W / (m²). The calcium silicate sleeve (2) of K) is inserted into the fixed flange barrel (1), and then the calcium silicate segmented sleeve (3) composed of 2-4 arc-shaped structures is inserted into the preset position of the calcium silicate sleeve (2). The splicing gap is filled with high-temperature resistant sealant with a temperature resistance of not less than 1200℃. Finally, the fixed flange barrel (1) is fixed to the main body of the printing equipment by bolts. The bolt tightening torque meets the equipment installation specifications. 1.3 Assembly of telescopic conveyor components: Align the top step of the small tube liner (4) made of silicon nitride ceramic material with an inner wall roughness Ra≤0.8μm with the calcium silicate split sleeve (3) and fix it by snap-fit; put the small tube outer protective plate (5) made of 304 stainless steel with a thickness of 8-12mm on the outside of the small tube liner (4) and snap its upper flange edge with the bottom of the fixed flange barrel (1) to ensure that the flange edge bearing strength meets the requirement of ≥20MPa; fit the upper step of the large tube liner (7) made of silicon nitride ceramic material with the lower flange of the small tube outer protective plate (5), add alumina ceramic fiber cotton insulation cotton with a thickness of 15-25mm and a compression rebound rate of ≥85% at the mating surface, and finally put the 304 stainless steel outer protective plate (6) with a thickness of 8-12mm and an impact strength of ≥20J / cm² on the outside of the large tube liner (7); 1.4 Assembly of Buffer Components and Connecting Components: Install the porous ceramic filter buffer plate (12) with a pore size of 0.1-0.5mm and a porosity of 30%-50% into the heat-resistant cast steel buffer box (8) with a temperature resistance upper limit of not less than 800℃; connect the buffer box (8) with the inner lining of the large pipe (7) with a gap of 0.5-1.5mm, and fix the buffer box (8) in the crucible cavity; install the hard alloy nozzle plate (15) with a hardness ≥ HRC60 into the preset mounting hole of the crucible bottom plate (13), using a 4-6 nozzle with a specification of M8-M12. One bolt connects and tightens the nozzle pressure plate (14) and the nozzle plate (15) to ensure that the stainless steel electric heating tube with a power of 500-1000W and a heating temperature range of 200-600℃ inside the nozzle pressure plate (14) is accurately positioned, and magnesium oxide insulating material is filled between the heating tube and the nozzle pressure plate (14) to ensure that the insulation resistance is ≥100MΩ. 1.5 Debugging: Start the equipment and check the sliding and telescopic performance of the telescopic conveyor components to ensure that the large pipe unit slides smoothly relative to the small pipe unit without any jamming; turn on the heating tube inside the nozzle pressure plate (14) and check whether the heating temperature can be stably maintained within the set range. At the same time, check the sealing of each connection part to ensure that there is no leakage. Step Two: Liquid Metal Preparation and Transfer 2.1 Metal smelting: The metal to be printed (such as aluminum ingot) is put into the smelting furnace and heated and smelted according to the requirements of the metal material smelting process. The smelting temperature is determined according to the type of metal. For example, the smelting temperature of aluminum liquid is controlled at 660-700℃. Refining agents are added during the smelting process to remove impurities and ensure the purity of the molten metal. 2.2 Metal liquid transportation: The purified metal liquid is transported to the printing equipment through a chute. The aluminum hole at the bottom of the chute is connected to the calcium silicate sheath (2). The flow control switch at the aluminum hole of the chute is adjusted to control the metal liquid transportation speed at 1-3L / min. The metal liquid enters the inner lining of the small tube (4) and the inner lining of the large tube (7) in sequence, and finally flows into the buffer tank (8). Step 3: Coordinating Buffering and Flow Stabilization with Crucible Lifting 3.1 Buffering and Filtration: After the molten metal enters the buffer tank (8), it is filtered and impurities are removed by the filter buffer plate (12). At the same time, the flow rate is slowed down, so that the flow rate of the molten metal is reduced to 0.5-1m / s. The buffered molten metal enters the crucible cavity through 3-5 evenly distributed liquid passage holes with a diameter of 10-20mm at the bottom of the buffer tank (8). If the molten metal is transported in large quantities, the excess molten metal is discharged through the overflow groove with a width of 8-15mm and a depth of 5-10mm on the side of the buffer tank (8) to prevent overflow. 3.2 Crucible lifting control: In the initial state, the lifting mechanism is controlled to keep the crucible in a high position, and then the crucible is lowered to the printing start height. The lowering speed is controlled at 5-10 mm / s. After the printing operation starts, as the height of the printed part increases, the lifting mechanism drives the printing crucible to rise slowly at a speed of 2-5 mm / s. The crucible drives the buffer box (8) to move upward. The buffer box (8) pushes the inner liner of the large tube (7) to slide upward along the lower flange of the outer protective plate (5) of the small tube. The large tube unit and the small tube unit slide and extend relative to each other, always keeping the buffer box (8) and the crucible cavity close to each other. The close distance is controlled at 1-3 mm. Step 4: Monitoring and Ending of the Printing Process 4.1 Process monitoring: During the printing process, the temperature of the molten metal, the conveying speed, the lifting speed of the crucible and the temperature of the nozzle plate (15) are monitored in real time. The temperature fluctuation of the molten metal is controlled within ±10℃. The temperature of the nozzle plate (15) is maintained within the set value ±5℃ through the heating tube. If any parameter is abnormal, the equipment will automatically alarm and stop printing. It will continue after the fault is cleared. 4.2 Printing Completion: After the printed part reaches the preset size, first turn off the chute flow switch to stop the metal liquid delivery. After the remaining metal liquid in the crucible has finished printing, turn off the nozzle heating tube, control the lifting mechanism to lower the crucible to the initial position, take out the printed part, clean and maintain the equipment, remove the liquid delivery tube and residual metal slag in the crucible, check the integrity of each component, and prepare for the next printing.

8. The metal printing method according to claim 7, characterized in that, In step 2.1, if the metal to be printed is aluminum alloy, an Al-Ti-B grain refiner needs to be added during melting, with an addition amount of 0.1%-0.3% of the aluminum alloy mass, in order to refine the grains; in step 3.2, during the crucible lifting process, the position of the crucible is monitored in real time by a displacement sensor, and the displacement accuracy is controlled within ±0.1mm to ensure that the lifting action is precisely matched with the printing rhythm.

9. The metal printing method according to claim 7, characterized in that, In step 4.1, an infrared thermometer is used to monitor the temperature of the molten metal with an accuracy of ±1℃, and a flow meter is used to monitor the flow rate of the molten metal with an accuracy of ±0.1L / min, to ensure the accuracy of the parameters monitored during the printing process.

10. The metal printing method according to claim 7, characterized in that, In step 1.3, after the telescopic conveying component is assembled, an airtightness test is required. Compressed air of 0.3-0.5MPa is introduced into the infusion pipe and the pressure is maintained for 30 minutes. The pressure drop is ≤0.02MPa to ensure that the insulation cotton's sealing performance meets the requirements. In step 1.4, after the buffer box (8) is fixed, a levelness test is required. The levelness deviation is ≤0.1mm / m to prevent uneven flow of molten metal in the buffer box (8).

Images