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CN-122007606-A - Local atmosphere protection device and method for laser fuse additive manufacturing

CN122007606ACN 122007606 ACN122007606 ACN 122007606ACN-122007606-A

Abstract

The invention discloses a local atmosphere protection device for laser fuse additive manufacturing, which relates to the technical field of metal additive manufacturing and comprises a printing substrate, a laser, a supporting component and a main protection air curtain component, wherein the laser is arranged above the printing substrate, the supporting component is arranged on the printing substrate and is used for supporting the laser, and the supporting component comprises an elastic upper cover body and a rigid lower cover body. Through the upper and lower split structure of 'upper moving and lower static' and dynamic sealing connection design, the upper cover body moves along with the laser, the rigid lower cover body keeps fixed relative to the printing substrate and maintains the cooperative relation of constant gaps, and the contradiction that the traditional rigid cover is difficult to consider between dynamic movement and stable gaps is effectively solved.

Inventors

  • GUO WEI
  • FENG LINGYUN
  • Mi Hangbiao

Assignees

  • 华中科技大学

Dates

Publication Date
20260512
Application Date
20260123

Claims (10)

  1. 1. The utility model provides a local atmosphere protection device of laser fuse vibration material disk, includes printing base plate and laser instrument, the laser instrument sets up in the top of printing base plate, its characterized in that still including set up in supporting component and main protection air curtain subassembly on the printing base plate, supporting component is used for supporting the laser instrument, and supporting component includes elasticity upper portion cover body and rigidity lower part cover body, elasticity upper portion cover body passes through dynamic seal connecting portion and is connected with rigidity lower part cover body, and forms a cavity between elasticity upper portion cover body and the rigidity lower part cover body, main protection air curtain subassembly and cavity intercommunication, main protection air curtain subassembly is used for letting in gas to the cavity in order to maintain the atmospheric pressure balance in the cavity, in the vibration material vibration manufacturing process, laser instrument drive elasticity upper portion cover body removes and takes place elastic deformation, and rigidity lower part cover body then keeps fixedly for dynamic seal connecting portion adaptation upper and lower cover body relative displacement and keep the cavity sealed.
  2. 2. The local atmosphere protection device for laser fuse additive manufacturing of claim 1, wherein the laser is disposed on the resilient upper housing.
  3. 3. The local atmosphere protection device for laser fuse additive manufacturing according to claim 2, wherein the rigid lower cover is fixedly arranged on an annular rigid structure of the equipment lathe bed, an opening is formed in the bottom of the rigid lower cover, and a gap of 0.5-3mm is reserved between the bottom edge of the rigid lower cover and the surface of the printing substrate.
  4. 4. A local atmosphere protection device for laser fuse additive manufacturing according to claim 3, wherein the main protective gas curtain component comprises an annular pressure equalizing cavity and an annular micro-pore plate communicated with and annularly distributed at the bottom of the rigid lower cover body, and a plurality of circles of dense micro-pores are arranged on the annular micro-pore plate and are used for spraying high-purity inert protective gas in an inclined direction in the cavity body perpendicular to the surface of the printing substrate or relative to the normal direction of the printing substrate, forming a laminated gas curtain above the surface of the printing substrate and overflowing through the gap.
  5. 5. The local atmosphere protection device for laser fuse additive manufacturing according to claim 4, wherein the main protective gas curtain assembly further comprises an annular exhaust hole strip, which is arranged near the upper end of the rigid lower cover body and the dynamic sealing connection part, and is provided with a plurality of exhaust micropores along the circumferential direction, and the exhaust micropores are used for exhausting mixed gas in the cavity and maintaining micro-positive pressure and ultra-low oxygen environment in the cavity; Wherein, the protective gas is continuously introduced through the main protective gas curtain component and flows from bottom to top, and an organized gas flow channel from bottom to top is formed in the cavity by combining bottom gap overflow and annular vent hole strip exhaust.
  6. 6. The local atmosphere protection device for manufacturing the laser fuse additive according to claim 5, wherein the diameter of micropores on the annular micropore plate is 0.1-0.5mm, the hole pitch is 2-5 times of the aperture, and the air outlet direction of the micropores is perpendicular to the surface of the printing substrate or inclined towards the inside of the cover body by 0-15 degrees relative to the normal direction of the printing substrate.
  7. 7. The local atmosphere protection device for laser fuse additive manufacturing of claim 6, wherein a gap between a bottom edge of the rigid lower cap and the print substrate surface is 0.5-3mm.
  8. 8. The local atmosphere protection device for laser fuse additive manufacturing according to claim 7, wherein the elastic upper cover body is made of a high-temperature-resistant flexible material, and a wire feeding guide pipe and a side air blowing pipe are arranged on the elastic upper cover body; the side wall of the elastic upper cover body is provided with at least one rigid mounting seat which is used for fixing the wire feeding guide pipe and the side air blowing pipe so as to realize the integrated arrangement of wire feeding and local protection.
  9. 9. The local atmosphere protection device for laser fuse additive manufacturing according to claim 8, wherein the diameter of the exhaust micropore of the annular exhaust hole strip is 0.5-2mm, so as to achieve stable maintenance of exhaust capacity and local micro-positive pressure.
  10. 10. A local atmosphere protection method for metal laser fuse additive manufacturing, which is applied to the local atmosphere protection device for laser fuse additive manufacturing according to claim 9, and is characterized in that the local atmosphere protection method for metal laser fuse additive manufacturing comprises the following steps: Firstly, introducing high-purity inert protective gas into a main protective gas curtain component, then spraying the protective gas through micropores on an annular micropore plate after buffering the protective gas through an annular pressure equalizing cavity, forming a laminated laminar gas curtain above the surface of a printing substrate, overflowing through gaps, and simultaneously establishing micro positive pressure in a cavity enclosed by an elastic upper cover body and a rigid lower cover body; Starting a laser and an external wire feeding mechanism, wherein the laser outputs a laser beam and forms a molten pool on the surface of a printing substrate, and feeding a metal wire material into a preheating zone in front of the molten pool through a wire feeding conduit; in the additive manufacturing process, the laser drives the elastic upper cover body to move and elastically deform, and the rigid lower cover body is kept fixed, so that the dynamic sealing connecting part adapts to the relative displacement between the upper cover body and the lower cover body and keeps the cavity sealed, thereby protecting gas continuously flows from bottom to top and forming a stable local low-oxygen environment around a molten pool and the tail end of the metal wire; Step three, along with the increase of the number of forming layers, the formed target member gradually grows upwards in the inner cavity of the rigid lower cover body, the height of the interface where the molten pool is located is increased along with the increase, but the rigid lower cover body is fixed on the equipment bed body through the supporting structure, the gap between the bottom edge of the rigid lower cover body and the printing substrate is kept constant in the whole material adding process, and the bottom annular gap is positioned in the outer edge area of the target member and is not blocked by the target member, so that the molten pool is always in the range of the low-oxygen cavity filled with inert gas in the whole material adding process; and fourthly, after the formation of the target component is completed, closing the laser and the external wire feeding mechanism, continuously operating the main protective gas curtain component at a lower flow rate, cooling the molten pool area and the high Wen Mubiao component in a low-oxygen environment, gradually reducing the flow rate of protective gas and closing the gas supply after the temperature is reduced to a safe range, releasing the device, and checking and cleaning the elastic upper cover body, the annular micro-pore plate and the dynamic sealing connection part.

Description

Local atmosphere protection device and method for laser fuse additive manufacturing Technical Field The invention relates to the technical field of metal additive manufacturing, in particular to a local atmosphere protection device and method for laser fuse additive manufacturing. Background The core principle of the paraxial laser fuse additive manufacturing is based on laser cladding, and continuous metal wires are fed into a molten pool by arranging laser beams and a wire feeding mechanism at a certain side included angle, so that efficient additive forming of metal components with complex structures and large sizes is realized. Compared with the traditional powder bed melting or powder feeding laser cladding process, the paraxial laser fuse additive has the advantages of high material utilization rate, low wire cost, small dust hazard, high forming efficiency and the like, and has wide application prospect in the manufacturing and repairing fields of high-activity metal components such as high-strength aluminum alloy, magnesium alloy, titanium alloy and the like. However, high-activity metals such as magnesium, aluminum, titanium and the like have extremely high affinity for oxygen at high temperature, and severe oxidation occurs even in an environment with low oxygen content, so that defects such as oxide inclusion, element burning loss, air holes and the like are caused, and the strength, plasticity and fatigue life of a formed part are seriously affected. Therefore, in the paraxial laser fuse additive manufacturing process, a stable low-oxygen or ultra-low oxygen local protective atmosphere needs to be established and maintained near the molten pool and the wire preheating zone. The invention discloses an invention patent document of an authority notice number 200910122291.0, the authority notice day is 2012-04-18, the name is a controllable atmosphere protection device for laser rapid forming of titanium alloy parts, the controllable atmosphere protection device comprises a rigid sealing box body and a flexible bag type sealing cover, an air charging port and an air discharging port are arranged on the rigid sealing box body, valves are respectively arranged on the air charging port and the air discharging port, in the air discharging process, air in a cavity is pumped out along with the air discharging port, the flexible bag type sealing cover is gradually close to the inner wall and the cavity bottom of the rigid sealing box body under the negative pressure effect and is finally tightly attached to the inner wall and the cavity bottom of the rigid sealing box body to discharge all air in the cavity, then the valves on the air discharging port are closed, the valves on the air charging port are opened, and in the process of charging the protective gas, and the flexible bag type sealing cover is lifted and inflated accordingly, so that the required protective atmosphere state is formed in the cavity. In the prior art, the common atmosphere protection mode for paraxial laser fuse additive manufacturing mainly comprises (1) a side blowing protection gas mode, namely, inert gas is sprayed to a molten pool area through one or more side nozzles so as to reduce the oxygen concentration around the molten pool. The method has the advantages of simple structure and easy integration, but has obvious defects that firstly, the tail end of the metal wire is in a high-temperature preheating state before entering a molten pool, is often positioned at the edge or dead angle of a side blowing air flow, is insufficient in protection and is easy to oxidize, secondly, the side blowing air flow is open turbulence, a uniform protective air curtain is difficult to form at the tail part of the molten pool and in a complex geometric area, local mixing is serious, the protection effect is unstable, thirdly, the side blowing air field is easy to be disturbed by the environmental air flow and the operation condition, and the flow field repeatability is poor. (2) And in the mode of an integral atmosphere glove box, the integral processing system is arranged in a large-scale closed cavity, and an integral low-oxygen environment is formed by filling high-purity inert gas, so that the protection of the integral processing area is realized. The mode has good protection effect, but needs a huge closed box body and a complex atmosphere control system, the equipment cost and the operation and maintenance cost are extremely high, and the size of the cavity limits the size and the movement range of a workpiece, so that the mode is not suitable for large-size components and flow line production scenes. Therefore, when the high-activity metal is processed in the current paraxial laser fuse additive manufacturing, a local atmosphere device which can dynamically move along with a laser, keep a proper constant gap with a substrate and can provide continuous, uniform and stable protection for a molten pool and a wire preheating zone is still