Metal 3D printing closed-loop control device

Abstract

The metal 3D printing closed-loop control device comprises a laser cladding spray head, a laser variable light spot mechanism, a flexible nozzle, an adjusting assembly and a CCD camera module, the CCD camera module is used for monitoring the state of a molten pool on a substrate in real time, and the laser variable light spot mechanism is used for adjusting the state of the molten pool according to monitoring data of the CCD camera module. And the adjusting assembly is used for adjusting the size of a laser beam spot generated by the laser cladding spray head, and the adjusting assembly is used for adjusting the size of the spraying end of the flexible spray nozzle according to monitoring data of the CCD camera module. The laser variable light spot mechanism and the adjusting assembly are matched with a closed-loop control system of the CCD camera module, so that the size of a light spot and the size of an opening of the flexible nozzle can be adjusted in real time according to the part forming requirement, real-time dynamic adjustment is achieved according to the working condition requirement, and the production efficiency is improved. Accumulation forming and green repairing of formed parts with different section sizes are completed, and it is guaranteed that the forming process is simple, rapid, efficient and accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of laser cladding, and particularly relates to a closed-loop control device for metal 3D printing. Background Art

[0002] After retrieval in the fields of advanced manufacturing technologies such as laser cladding and 3D printing, it is found that the patent numbers: CN106444049A laser broadband cladding device, CN105562951A laser in-beam wire feeding device for laser cladding, CN107627002A laser cladding device, CN107217257A laser cladding device, and CN106583726A laser multi-beam cladding device all adopt the combination of a beam splitter and a focusing lens to separate and focus a laser beam into a laser beam presenting a rectangular hollow or a circular hollow, and then the laser cladding material enters the hollow area of the light spot from one side, so that the laser cladding material ejection flow and the hollow light spot achieve a coaxial relationship, realizing the in-beam coaxial relationship in principle.

[0003] However, the above-mentioned publicly disclosed patented technologies still have the following deficiencies in part repair and forming: 1. When performing three-dimensional forming or repair of irregular parts such as variable cross-section overhanging structure parts, unequal wall thickness structure parts, and variable cross-section inverted suspension, due to the fixed light spot size and powder jet flow shape size of the currently publicly disclosed patents, generally, it is necessary to rely on a robot or an X, Y, Z motion guide rail to drive the nozzle to change the spatial position, and coordinate and adjust process parameters such as laser power, powder feeding rate, scanning speed, and defocus amount. However, in this adjustment process, the coordinated control system of process parameters and the spatial angle of the nozzle is extremely complex, resulting in high costs, long time consumption, and even the problem that the repair and forming of complex three-dimensional parts cannot be achieved.

[0004] 2. In the existing patent solutions, the shapes of the light spot and the powder flow lack the ability of flexible change and cannot be adjusted according to different working conditions, resulting in problems of single function, limited applicable working conditions, difficulty in meeting diverse usage requirements, and high usage costs.

[0005] 3. In the existing patented technologies, if the powder feeding hole diameter needs to be changed, it is necessary to stop the machine and replace nozzles with different diameters. Therefore, the nozzle aperture cannot be adjusted in real time during the green repair process of cladding, and further, the size of the powder beam delivered to the molten pool cannot be flexibly controlled, severely restricting the forming efficiency of complex parts and even causing the forming work of some complex parts to be unable to be carried out.

[0006] 4. In the existing patented technologies, if the light spot size needs to be changed, it needs to be achieved by adjusting the defocus amount position by changing the Z-axis of the nozzle. However, this method has low sensitivity and cannot quickly respond to changes in working conditions, having a greater impact on the forming efficiency and accuracy of complex parts such as variable cross-section overhanging structure parts, unequal wall thickness structure parts, and variable cross-section inverted suspension. Summary of the Invention

[0007] The present invention provides a closed-loop control device for metal 3D printing to solve the problems raised in the above-mentioned background art.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is: A closed-loop control device for metal 3D printing includes a laser cladding nozzle, a laser variable spot mechanism, a flexible nozzle, an adjustment component, and a CCD camera module. The CCD camera module is used to monitor the molten pool state on the substrate in real time. The laser variable spot mechanism is used to adjust the size of the laser beam spot generated by the laser cladding nozzle according to the monitoring data of the CCD camera module. The adjustment component is used to adjust the size of the ejection end of the flexible nozzle according to the monitoring data of the CCD camera module. The flexible nozzle is connected to one end of the powder delivery pipe inside the laser cladding nozzle, and the laser beam generated by the laser cladding nozzle is coaxially arranged with the flexible nozzle and is used to wrap the flexible nozzle.

[0009] Preferably, the laser variable spot mechanism includes a cylinder connected to the bottom of the collimator mechanism in the laser cladding nozzle, a concave lens and a convex lens arranged inside the cylinder, and a cam mechanism connected to the concave lens. The cam mechanism is used to adjust the distance between the concave lens and the convex lens. The concave lens is arranged directly above the convex lens, and the laser beam generated by the collimator mechanism in the laser cladding nozzle passes through the concave lens and the convex lens in sequence.

[0010] Preferably, the cam mechanism includes a first motor installed on a connecting plate, an eccentric cam connected to the output end of the first motor, a connecting rod and a return spring connected to the concave lens. One end of the connecting rod extends to the outside of the cylinder and fits on the eccentric cam, and the end of the return spring away from the concave lens is connected to the inner wall of the cylinder.

[0011] Preferably, an adjustment opening is formed through the surface of the cylinder, and the connecting rod is movably arranged inside the adjustment opening.

[0012] Preferably, the adjustment component includes a spiral clamp surrounding the outer side of the flexible nozzle, a driving member for driving the spiral clamp to tighten or loosen, and a connecting ring arranged outside the connection part of the powder delivery pipe and the flexible nozzle. The spiral clamp and the driving member are respectively connected to the connecting ring.

[0013] Preferably, the spiral clamp includes a steel belt with ratchet grooves, a hoop shell connected to the steel belt, and a worm member arranged inside the hoop shell. The driving member is used to drive the worm member to tighten or loosen the steel belt, and the hoop shell is fixedly installed on the connecting ring.

[0014] Preferably, the driving member includes an electric torsion ring and a second motor. The second motor is fixedly installed on the connecting ring, and one end of the electric torsion ring is connected to the output end of the second motor, and the other end of the electric torsion ring is connected to one end of the worm rod member.

[0015] Preferably, the CCD camera module includes a camera and a signal transmitter. The CCD camera module is electrically connected to the laser variable spot mechanism and the adjustment component through the signal transmitter.

[0016] Preferably, the laser cladding nozzle includes a connecting plate, an upper cover installed on the connecting plate, a support frame connected to the bottom of the upper cover, a wire feeding pipe support connected to the support frame, and a collimator mechanism disposed above the upper cover. The bottom end of the laser variable spot mechanism is connected to the upper cover, the top end of the laser variable spot mechanism is connected to the collimator mechanism, and a beam splitter mechanism and a plurality of reflection focusing mirror mechanisms are installed on the top of the support frame. The plurality of reflection focusing mirror mechanisms are equidistantly distributed with the beam splitter mechanism as the center.

[0017] Preferably, a plurality of reflection optical path through holes corresponding to the reflection focusing mirror mechanisms one by one are formed on the support frame. The laser beam emitted from the collimator mechanism is projected through the through holes of the reflection optical path to realize the wrapping of the flexible nozzle.

[0018] By adopting the above technical solutions, the beneficial effects obtained by the present invention are as follows: In the present invention, through the closed-loop control system of the laser variable spot mechanism and the adjustment component in cooperation with the CCD camera module, the present invention can adjust the spot and the opening size of the flexible nozzle in real time according to the requirements of part forming, so as to realize real-time dynamic adjustment according to the working conditions, complete the stacking forming and green repair of forming parts with different cross-sectional sizes, ensure that the forming process is simple and fast, and reduce costs and increase efficiency.

[0019] In the present invention, according to the working condition requirements of laser cladding green repair or laser 3D printing forming, through CCD closed-loop feedback, the shape and size of the powder flow and the spot size are adaptively adjusted according to the requirements, so that the size of the powder flow and the energy size of the spot are adaptively adjusted until the working condition requirements are met, improving the forming quality, efficiency and functional diversity requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0021] Figure 2 It is a schematic diagram of the first position of the concave lens and the convex lens after the section of the present invention.

[0022] Figure 3Schematic diagram of the second position of the rear concave lens and convex lens of the present invention after sectioning.

[0023] Figure 4 Schematic diagram of the laser spot size changing mechanism of the present invention.

[0024] Figure 5 Schematic diagram of the structure of the adjusting assembly of the present invention.

[0025] Figure 6 Schematic diagram of the enlarged structure of the flexible nozzle of the present invention.

[0026] Figure 7 Schematic diagram of the reduced structure of the flexible nozzle of the present invention.

[0027] Figure 8 Schematic diagram of the laser beam shrinking path.

[0028] Figure 9 Schematic diagram of the laser beam expanding path.

[0029] Figure 10 Schematic diagram of the comparison after adjustment between the concave lens and convex lens of the present invention.

[0030] Figure 11 Schematic diagram of the present invention for the forming of complex workpieces.

[0031] Figure 12 Schematic diagram of the present invention for the forming of workpieces with unequal wall thicknesses.

[0032] Figure 13 Schematic diagram of the control flow of the present invention.

[0033] In the figure: 1. Laser cladding spray head; 11. Connecting plate; 12. Upper cover; 13. Support frame; 14. Wire feeding tube support; 15. Collimator mechanism; 16. Beam splitter mechanism; 17. Reflective focusing mirror mechanism; 18. Reflective light path through hole. 2. Laser spot size changing mechanism; 21. Cylinder; 22. Concave lens; 23. Convex lens; 24. Cam mechanism; 241. First motor; 242. Eccentric cam; 243. Connecting rod; 244. Return spring; 25. Adjusting port. 3. Powder feeding tube; 4. Flexible nozzle. 5. Adjusting assembly; 51. Spiral clamp; 511. Steel strip; 512. Hoop shell; 513. Spiral member; 52. Driving member; 521. Electric torsion ring; 522. Second motor. 6. CCD camera module; 7. Substrate; 8. Connecting ring. Detailed implementation manner

[0034] To better understand the above objects, features, and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0035] In the present invention, the term "plurality" refers to two or more, unless otherwise clearly defined. The term "and / or" used herein includes any and all combinations of one or more of the related listed items. Terms such as "installed", "connected", "joined", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "joined" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] It should be noted that when an element is referred to as "assembled on", "installed on", "fixed on", or "set on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation.

[0037] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the present invention is not limited by the specific embodiments disclosed in the following specification. Embodiment

[0038] As Figures 1 - 13 shown, the present invention provides a closed-loop control device for metal 3D printing, including a laser cladding nozzle 1, a laser variable spot mechanism 2, a flexible nozzle 4, an adjustment assembly 5, and a CCD camera module 6. The CCD camera module 6 is used to monitor the molten pool state on the substrate 7 in real time. The laser variable spot mechanism 2 is used to adjust the size of the laser beam spot generated by the laser cladding nozzle 1 according to the monitoring data of the CCD camera module 6. The adjustment assembly 5 is used to adjust the size of the ejection end of the flexible nozzle 4 according to the monitoring data of the CCD camera module 6. The flexible nozzle 4 is connected to one end of the powder delivery tube 3 in the laser cladding nozzle 1, and the laser beam generated by the laser cladding nozzle 1 is coaxially arranged with the flexible nozzle 4 and is used to wrap the flexible nozzle 4.

[0039] As a further aspect, the laser cladding nozzle 1 includes a connecting plate 11, an upper cover 12 mounted on the connecting plate 11, a support frame 13 connected to the bottom of the upper cover 12, a wire feeding pipe support 14 connected to the support frame 13, and a collimator mechanism 15 disposed above the upper cover 12. The bottom end of the variable laser spot mechanism 2 is connected to the upper cover 12, and the top end of the variable laser spot mechanism 2 is connected to the collimator mechanism 15. A beam splitter mechanism 16 and a plurality of reflecting and focusing mirror mechanisms 17 are mounted on the top of the support frame 13, and the plurality of reflecting and focusing mirror mechanisms 17 are equidistantly distributed around the beam splitter mechanism 16. Among them, the beam splitter in the beam splitter mechanism 16 is provided with at least two beam splitting surfaces, and each beam splitting surface is a plane. The reflecting and focusing mirrors in the plurality of reflecting and focusing mirror mechanisms 17 respectively correspond to the beam splitting surfaces on the beam splitter, so as to enable the reflecting and focusing mirrors to receive the reflected light beam emitted by the collimator mechanism 15 and simultaneously convert the reflected light beam into a focused light beam.

[0040] As a further aspect, a plurality of reflecting light path through holes 18 corresponding to the reflecting and focusing mirror mechanisms 17 one by one are formed on the support frame 13, and the laser beam emitted from the collimator mechanism 15 is projected through the through holes of the reflecting light path through holes 18 to wrap the flexible nozzle 4. Combining Figure 2 、 Figure 3 and Figure 8 As shown, when the light beam is input into the collimator mechanism 15 from the QBH head, the light beam is emitted from the collimating mirror in the collimator mechanism 15 to the concave lens 22, and then projected onto the beam splitter of the beam splitter mechanism 16 through the convex lens 23. Then, the beam splitter can split the laser beam into multiple light beams and project them onto the reflecting and focusing mirrors of the corresponding reflecting and focusing mirror mechanisms 17. Finally, the laser beam reflected by the reflecting and focusing mirror is projected through the reflecting light path through hole 18 to form an envelope spot below the flexible nozzle 4.

[0041] It should be noted that in this embodiment, three focused laser beams are used for illustration; and the beam splitter in the beam splitter mechanism 16 uses three beam splitting surfaces. Therefore, the beam splitter mechanism 16 with three beam splitting surfaces can form a triangular prism as shown in the figure of this solution; and, the reflecting and focusing mirror described above is a reflecting mirror.

[0042] As a further aspect, the focused light beam generated by the laser cladding nozzle 1 and the flexible nozzle 4 are in a coaxial relationship to wrap the flexible nozzle 4 and the powder beam, effectively ensuring that the powder flow passing through the flexible nozzle 4 can be fully and uniformly wrapped by the laser beam, improving the powder utilization rate and forming accuracy.

[0043] It should be noted that the multi-beam technology formed by the above-described laser cladding nozzle 1 is a known and publicly disclosed technology. For more details, reference can be made to the publicly cited patents in the background technology, and this article will not elaborate further on this.

[0044] As a further improvement, protective mirrors are respectively installed in the reflection optical path through holes 18 on the support frame 13, and the protective mirrors are used to prevent pollutants from contaminating the lenses inside the upper cover 12.

[0045] As a further improvement, the laser spot size changing mechanism 2 includes a cylinder 21 connected to the bottom of the collimator mechanism 15 in the laser cladding nozzle 1, a concave lens 22 and a convex lens 23 arranged inside the cylinder 21, and a cam mechanism 24 connected to the concave lens 22. The cam mechanism 24 is used to adjust the distance between the concave lens 22 and the convex lens 23. The concave lens 22 is arranged directly above the convex lens 23, and the laser beam generated by the collimator mechanism 15 in the laser cladding nozzle 1 sequentially passes through the concave lens 22 and the convex lens 23.

[0046] Combined with Figure 2 、 Figure 4 and Figure 8 As shown, the concave lens 22 in the laser spot size changing mechanism 2 is on the top and the convex lens 23 is at the back. When the laser beam is emitted, the laser beam can first pass through the concave lens 22, so that the concave lens 22 can diverge the light, promoting the divergence of the light beam; and after the diverged light enters the convex lens 23, the convex lens 23 can converge the diverged light into parallel light. Therefore, with the combined action of the divergence of the concave lens 22 and the convergence of the convex lens 23, the diameter of the outgoing light beam passing through the laser spot size changing mechanism 2 is enlarged or reduced compared with the incident light beam and remains parallel, which is beneficial to the subsequent conversion into laser beams with different diameters for irradiating the spot, achieving the effect of variable spot size, so as to meet the needs of green repair of parts under different working conditions and ensure the forming efficiency and precision of complex parts.

[0047] As a further improvement, the cam mechanism 24 includes a first motor 241 installed on the connecting plate 11, an eccentric cam 242 connected to the output end of the first motor 241, a connecting rod 243 and a return spring 244 connected to the concave lens 22. One end of the connecting rod 243 extends outside the cylinder 21 and fits on the eccentric cam 242, and the end of the return spring 244 away from the concave lens 22 is connected to the inner wall of the cylinder 21. Among them, an adjustment opening 25 is formed through the surface of the cylinder 21, and the connecting rod 243 is movably arranged inside the adjustment opening 25.

[0048] When the first motor 241 works to drive the eccentric cam 242, the eccentric cam 242 can cause the connecting rod 243 to drive the concave lens 22 to move downward, thereby reducing the distance between it and the fixed convex lens 23. And, at the initial distance, given the respective focal lengths of the concave lens 22 and the convex lens 23 and the condition of parallel light incident, according to the lens combination formula, the focal length of the combined lens changes, enhancing the beam convergence ability; therefore, after the concave lens 22 is adjusted downward, the laser beam irradiation spot will become smaller.

[0049] Conversely, when the first motor 241 operates to drive the eccentric cam 242, the eccentric cam 242 can cause the connecting rod 243 to drive the concave lens 22 to move upward. During this period, the return spring 244 synchronously drives the concave lens 22 to move upward, thereby increasing the distance between it and the fixed convex lens 23. Moreover, under the conditions of known incident beam characteristics and the respective focal lengths of the concave lens 22 and the convex lens 23, according to the lens imaging formula and the principle of reversibility of light paths, the distance is accurately adjusted to ensure that the light beam is first diverged by the concave lens 22 and then re-converged by the convex lens 23, ultimately achieving beam amplification. After the concave lens 22 is adjusted to move upward, the irradiation spot of the laser beam will become larger.

[0050] As a further aspect, the adjusting assembly 5 includes a spiral clamp 51 surrounding the outer side of the flexible nozzle 4, a driving member 52 for driving the spiral clamp 51 to tighten or loosen, and a connecting ring 8 provided on the outer side of the connection part of the powder delivery pipe 3 and the flexible nozzle 4. The spiral clamp 51 and the driving member 52 are respectively connected to the connecting ring 8, and the connecting ring 8 is used to surround the object to be connected to achieve sealing or fastening connection at the connection of the powder delivery pipe 3 and the flexible nozzle 4.

[0051] Combined with Figure 5 、 Figure 6 and Figure 7 As shown, as a further aspect, the spiral clamp 51 includes a steel strip 511 with ratchet grooves, a hoop shell 512 connected to the steel strip 511, and a worm member 513 provided inside the hoop shell 512. The driving member 52 is used to drive the worm member 513 to tighten or loosen the steel strip 511, and the hoop shell 512 is fixedly installed on the connecting ring 8. Among them, the driving member 52 includes an electric torsion ring 521 and a second motor 522. The second motor 522 is fixedly installed on the connecting ring 8, and one end of the electric torsion ring 521 is connected to the output end of the second motor 522, and the other end of the electric torsion ring 521 is connected to one end of the worm member 513.

[0052] Among them, the spiral clamp 51 is fixed at the connection position of the flexible nozzle 4 and the powder delivery pipe 3 through the connecting ring 8. When the second motor 522 drives the electric torsion ring 521 to rotate, the electric torsion ring 521 can drive the worm member 513 inside the hoop shell 512 to rotate, causing the steel strip 511 to tighten or loosen when the worm member 513 rotates, thereby realizing the adjustable inner diameter of the flexible nozzle 4, ensuring real-time adjustment of the powder output of the flexible nozzle 4, eliminating the need for shutdown for replacement, saving time and effort, and effectively improving the forming efficiency of the workpiece.

[0053] As a further aspect, the CCD camera module 6 includes a camera and a signal transmitter. The CCD camera module 6 is electrically connected to the laser variable spot mechanism 2 and the adjustment assembly 5 through the signal transmitter. The morphology of the molten pool is monitored online by the CCD real-time monitoring camera, and the monitoring data is transmitted to the control system of the device in real time. And based on the intelligent algorithm, the control system precisely adjusts the cam mechanism 24. At the same time, with the real-time feedback mechanism, dynamic adaptive adjustment strategy, and intelligent data analysis, the efficiency of the repair operation is greatly improved.

[0054] As an embodiment, in combination with Figure 2 and Figure 8 as shown, after the light beam enters from the QBH head, it enters the collimating mirror in the collimator mechanism 15 and becomes a parallel light beam through refraction. Thus, when the first motor 241 drives the eccentric cam 242 to drive the concave lens 22 downward, the distance between it and the convex lens 23 is shortened, causing the parallel light beam to diverge first through the concave lens 22 and then converge into a parallel light beam again through the convex lens 23, realizing the reduction of the light beam diameter (see D4 in Figure 8 ). Furthermore, the distance between the light beam and the triangular prism is reduced, thereby changing the position where the light beam is refracted to the reflecting mirror to make it decrease, and finally causing the spot diameter reflected on the substrate 7 to become smaller (see D2 in Figure 8 ), ensuring the laser utilization rate.

[0055] As an embodiment, in combination with Figure 3 and Figure 9 as shown, after the light beam enters from the QBH head, it enters the collimating mirror in the collimator mechanism 15 and becomes a parallel light beam through refraction. Thus, when the first motor 241 drives the eccentric cam 242 to drive the concave lens 22 upward, the distance between it and the convex lens 23 is increased, causing the parallel light beam to diverge first through the concave lens 22 and then converge into a parallel light beam again through the convex lens 23, and expanding the light beam diameter (see D5 in Figure 9 ). The distance between the light beam and the triangular prism is expanded, thereby changing the position where the light beam is refracted to the reflecting mirror to make it expand, and finally causing the spot diameter reflected on the substrate 7 to become larger (see D2 in Figure 9 ), ensuring the laser utilization rate.

[0056] In combination with Figure 10 and Figure 12 as shown, for the forming of complex workpieces, the cross-sectional shape of the workpiece changes from large to small. During the forming process, it starts from the widest place of the cross-section of the workpiece. During this period, the powder feeding amount in the flexible nozzle 4 and the spot generated by the laser cladding nozzle 1 change synchronously. The specific manufacturing process is as follows: The CCD camera module 6 collects the state of the molten pool in real time and sends the collected information to the control center system. Based on the information data, the control center system sends a control signal to the cam mechanism 24, so that when the eccentric cam 242 rotates, it pushes the concave lens 22 upward, increasing the distance between the concave lens 22 and the convex lens 23, making the light spot larger to completely melt and clad more powder. At the same time, the driving member 52 drives the spiral clamp 51 to rotate, so that when the spiral clamp 51 is relaxed, the opening of the flexible nozzle 4 is enlarged, increasing the powder feeding amount, which is used to complete the forming of the widest part of the cross section of the workpiece.

[0057] Subsequently, with the continuous forming, the control center system continuously sends signals to the cam mechanism 24, so that the eccentric cam 242 drives the concave lens 22 to move downward through the connecting rod 243, reducing the distance between the concave lens 22 and the convex lens 23, and accurately reducing the diameter of the light spot. At the same time, the driving member 52 drives the spiral clamp 51 to rotate, so that when the spiral clamp 51 is tightened, the opening of the flexible nozzle 4 is reduced, reducing the powder feeding amount, which is used to complete the forming of the narrowest part of the cross section of the workpiece.

[0058] Combined Figure 11 and Figure 12 As shown, when forming a workpiece with unequal wall thickness, the cross-sectional shape of the workpiece changes from large to small. During the forming process, it starts from the widest part of the cross section of the workpiece. During this period, the powder feeding amount in the flexible nozzle 4 and the light spot generated by the laser cladding head 1 change synchronously. The specific manufacturing process is as follows: The CCD camera module 6 collects the state of the molten pool in real time and sends the collected information to the control center system. Based on the information data, the control center system sends a control signal to the cam mechanism 24, so that when the eccentric cam 242 rotates, it pushes the concave lens 22 upward, increasing the distance between the concave lens 22 and the convex lens 23, making the light spot larger to completely melt and clad more powder. At the same time, the driving member 52 drives the spiral clamp 51 to rotate, so that when the spiral clamp 51 is relaxed, the opening of the flexible nozzle 4 is enlarged, increasing the powder feeding amount, which is used to complete the forming of the widest part of the cross section of the workpiece.

[0059] Subsequently, with the continuous forming, the control center system continuously sends signals to the cam mechanism 24, so that the eccentric cam 242 drives the concave lens 22 to move downward through the connecting rod 243, reducing the distance between the concave lens 22 and the convex lens 23, and accurately reducing the diameter of the light spot. At the same time, the driving member 52 drives the spiral clamp 51 to rotate, so that when the spiral clamp 51 is tightened, the opening of the flexible nozzle 4 is reduced, reducing the powder feeding amount, which is used to complete the forming of the narrowest part of the cross section of the workpiece.

[0060] In summary, through the closed-loop control system of the laser spot-changing mechanism 2 and the adjustment component 5 in cooperation with the CCD camera module 6, the present invention can, according to the requirements of part forming, adjust the spot and the opening size of the flexible nozzle 4 in real time, so as to achieve real-time dynamic adjustment according to the working conditions, complete the stacked forming and green repair of formed parts with different cross-sectional sizes, and ensure that the forming process is simple and fast.

[0061] In addition, according to the working condition requirements of laser cladding green repair or laser 3D printing forming, through CCD closed-loop feedback, the powder flow shape and size as well as the spot size are adaptively adjusted according to the requirements, so that the powder flow size and the spot energy size are adaptively adjusted until the working condition requirements are met, improving the forming quality, efficiency and functional diversity requirements.

[0062] Combined Figure 12 As shown, when the CCD camera module 6 monitors in real time that the powder feeding of the flexible nozzle 4 is excessive, according to the working condition requirements, the cam mechanism 24 can be controlled to drive the concave lens 22 to move upward, so as to make the spot irradiated by the laser cladding nozzle 1 become larger, or the driving part 52 can be controlled to tighten the spiral clamp 51, so as to make the opening size of the flexible nozzle 4 shrink, achieving less powder feeding and meeting diverse usage requirements.

[0063] When the CCD camera module 6 monitors in real time that the powder feeding of the flexible nozzle 4 is too little, according to the working condition requirements, the cam mechanism 24 can be controlled to drive the concave lens 22 to move downward, so as to make the spot irradiated by the laser cladding nozzle 1 become smaller, or the driving part 52 can be controlled to loosen the spiral clamp 51, so as to make the opening size of the flexible nozzle 4 expand, achieving more powder feeding and meeting diverse usage requirements.

[0064] When the CCD camera module 6 monitors in real time that the spot diameter is large, according to the working condition requirements, the cam mechanism 24 can be controlled to drive the concave lens 22 to move downward, so as to make the spot irradiated by the laser cladding nozzle 1 become smaller, or the driving part 52 can be controlled to loosen the spiral clamp 51, so as to make the opening size of the flexible nozzle 4 expand, achieving more powder feeding and meeting diverse usage requirements.

[0065] When the CCD camera module 6 monitors in real time that the spot diameter is small, according to the working condition requirements, the cam mechanism 24 can be controlled to drive the concave lens 22 to move upward, so as to make the spot irradiated by the laser cladding nozzle 1 become larger, or the driving part 52 can be controlled to tighten the spiral clamp 51, so as to make the opening size of the flexible nozzle 4 shrink, achieving less powder feeding and meeting diverse usage requirements.

[0066] It should be noted that the adjustment of the spiral clamp 51 in the present invention can not only be implemented by the driving member 52 proposed in this solution, but also be adjusted manually in an embodiment. Specifically: use a screwdriver to tighten the worm rod 513 clockwise and evenly, so that the worm rod 513 drives the steel belt 511 to tighten, thereby ensuring that the spiral clamp 51 contracts and the opening of the flexible nozzle 4 decreases, reducing the powder delivery amount. On the contrary, use a screwdriver to slowly and evenly rotate the worm rod 513 counterclockwise, so that the spiral clamp 51 can be relaxed, ensuring that the opening of the flexible nozzle 4 increases and the powder delivery amount increases.

[0067] It should be emphasized that this solution aims to protect the physical structure and does not protect the circuit and software control. The proposal of the electronic control part in this article is only a supplementary explanation of the feasibility and authenticity of the present invention, and the present invention does not require protection for algorithms and circuit technologies. More importantly: although this solution does not elaborate on the electronic control program part, those skilled in the art can be familiar with and apply it based on professional knowledge.

[0068] In the description of this specification, the descriptions of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0069] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A closed-loop control device for metal 3D printing, characterized in that, It includes a laser cladding nozzle (1), a laser variable spot mechanism (2), a flexible nozzle (4), an adjustment assembly (5) and a CCD camera module (6). The CCD camera module (6) is used to monitor the molten pool state on the substrate (7) in real time. The laser variable spot mechanism (2) is used to adjust the size of the laser beam spot generated by the laser cladding nozzle (1) according to the monitoring data of the CCD camera module (6). The adjustment assembly (5) is used to adjust the size of the ejection end of the flexible nozzle (4) according to the monitoring data of the CCD camera module (6). The flexible nozzle (4) is connected to one end of the powder delivery pipe (3) inside the laser cladding nozzle (1), and the laser beam generated by the laser cladding nozzle (1) is coaxially arranged with the flexible nozzle (4) and is used to wrap the flexible nozzle (4).

2. The closed-loop control device for metal 3D printing according to claim 1, characterized in that The laser variable spot mechanism (2) includes a cylinder body (21) connected to the bottom of the collimator mechanism (15) in the laser cladding nozzle (1), a concave lens (22) and a convex lens (23) arranged inside the cylinder body (21), and a cam mechanism (24) connected to the concave lens (22). The cam mechanism (24) is used to adjust the distance between the concave lens (22) and the convex lens (23). The concave lens (22) is arranged directly above the convex lens (23), and the laser beam generated by the collimator mechanism (15) in the laser cladding nozzle (1) passes through the concave lens (22) and the convex lens (23) in sequence.

3. The closed-loop control device for metal 3D printing according to claim 2, wherein The cam mechanism (24) includes a first motor (241) installed on the connecting plate (11), an eccentric cam (242) connected to the output end of the first motor (241), and a connecting rod (243) and a return spring (244) connected to the concave lens (22). One end of the connecting rod (243) extends to the outside of the cylinder body (21) and fits on the eccentric cam (242), and the end of the return spring (244) far from the concave lens (22) is connected to the inner wall of the cylinder body (21).

4. The closed-loop control device for metal 3D printing according to claim 3, wherein An adjustment opening (25) is penetrated and opened on the surface of the cylinder body (21), and the connecting rod (243) is movably arranged inside the adjustment opening (25).

5. The closed-loop control device for metal 3D printing according to claim 1, wherein The adjustment assembly (5) includes a spiral clamp (51) surrounding the outer side of the flexible nozzle (4), a driving member (52) for driving the spiral clamp (51) to achieve tightening or loosening work, and a connecting ring (8) arranged outside the connecting part of the powder delivery pipe (3) and the flexible nozzle (4), and the spiral clamp (51) and the driving member (52) are respectively connected to the connecting ring (8).

6. The closed-loop control device for metal 3D printing according to claim 5, wherein, The spiral clamp (51) includes a steel strip (511) with ratchet grooves, a hoop shell (512) connected to the steel strip (511), and a worm member (513) arranged inside the hoop shell (512). The driving member (52) is used to drive the worm member (513) to achieve the tightening or loosening of the steel strip (511), and the hoop shell (512) is fixedly installed on the connecting ring (8).

7. The closed-loop control device for metal 3D printing according to claim 6, wherein The driving member (52) includes an electric torsion coil (521) and a second motor (522). The second motor (522) is fixedly installed on the connecting ring (8), and one end of the electric torsion coil (521) is connected to the output end of the second motor (522), and the other end of the electric torsion coil (521) is connected to one end of the worm rod member (513).

8. The closed-loop control device for metal 3D printing according to claim 1, characterized in that The CCD camera module (6) includes a camera and a signal transmitter. The CCD camera module (6) is electrically connected to the laser spot-changing mechanism (2) and the adjustment assembly (5) through the signal transmitter.

9. The closed-loop control device for metal 3D printing according to claim 1, wherein The laser cladding nozzle (1) includes a connecting plate (11), an upper cover (12) installed on the connecting plate (11), a support frame (13) connected to the bottom of the upper cover (12), a wire feeding pipe support (14) connected to the support frame (13), and a collimator mechanism (15) disposed above the upper cover (12). The bottom end of the laser spot-changing mechanism (2) is connected to the upper cover (12), the top end of the laser spot-changing mechanism (2) is connected to the collimator mechanism (15), and a beam splitter mechanism (16) and a plurality of reflection focusing mirror mechanisms (17) are installed on the top of the support frame (13). The plurality of reflection focusing mirror mechanisms (17) are equidistantly distributed around the beam splitter mechanism (16).

10. The metal 3D printing closed-loop control device according to claim 9, characterized in that, A plurality of reflection optical path through holes (18) corresponding to the reflection focusing mirror mechanisms (17) one by one are formed in the support frame (13). The laser beam emitted from the collimator mechanism (15) is projected through the through hole reflection optical path through holes (18) to wrap the flexible nozzle (4).

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