SYNCHRONOUS POWDER-FEEDING SPACE LASER MACHINING AND THREE-DIMENSIONAL FORMING METHOD AND DEVICE

Abstract

A method for synchronous powder-feeding space laser cladding and three-dimensional forming includes: dividing a three-dimensional solid into a plurality of forming units according to a form simplification and nozzle cladding scanning accessibility principle, and dividing each forming unit into a plurality of layers; employing a single-beam gas-carried power-feeding mode in a hollow annular laser; controlling a mechanical arm (7) to drive an in-laser powder-feeding nozzle (1) to move and scan along a predetermined trajectory in a filling area and a boundary area of the layer; and sequentially conducting cladding and stacking formation of the layer for the entire unit. A device includes an inside-laser powder-feeding nozzle (1), a laser generator (6), a mechanical arm (7), a control module (4), a transmission optical fiber (5), a gas-carried powder feeder (3) and a gas source (2).

Claims

1. A method for synchronous powder-feeding space laser cladding and three-dimensional forming, comprising the following steps: (1) dividing a multi-branch complex three-dimensional solid expected to be formed into at least one forming unit based on the principle of body simplification and nozzle cladding scanning accessibility, and selecting the forming sequence of each unit in turn, with each forming unit having a respective optimal forming growth direction and rule; (2) dividing the forming unit obtained in the step (1) into a number of layers in the stacking accumulating direction, each layer including at least one of a filling region and a boundary region; (3) using the hollow annular laser inside-laser single-beam gas-carried powder-feeding method to control a mechanical arm to drive an inside-laser powder-feeding nozzle to scan and move in the boundary region and the filling region of a layer along a predetermined track, so as to complete cladding, accumulating and forming of this layer, respectively; in scanning forming, the laser-powder spray axis of the inside-laser powder-feeding nozzle is always along the normal direction of the layer; when the filling region and the boundary region are inconsistent in the layering direction, i.e., the layers are not parallel to each other, the nozzle needs to be deflected to complete cladding forming of different regions, respectively; (4) after cladding forming of a layer, the nozzle retreats by a distance of thickness of one layer along the growth direction of a next layer, and completes scanning cladding forming of a new layer according to the step (3); repeating in this way, until the stacking accumulation of the entire forming unit is completed; wherein the nozzle needs to continuously change its position for each layer in forming the boundary of a curved surface, with the stacking forming always done along the bending direction of the boundary; and (5) after completing a forming unit, controlling the mechanical arm to move the inside-laser powder-feeding nozzle to the start position of a next forming unit, so as to repeat the steps (2), (3) and (4) for stacking accumulating forming of a new forming unit; repeating in this way, until completing all the unit accumulation of the entire three-dimensional solid.

2. The method for synchronous powder-feeding space laser cladding and three-dimensional forming according to claim 1, wherein in step (2), all the layers in the filling region, parallel to each other, are parallel to the base surface; when the boundary region is layered, it is sliced along the vertical direction of the boundary face; when the boundary face is straight faced, the layers are parallel to each other and equal in thickness; when the boundary face is a curved surface, the layers are neither parallel to each other nor equal in thickness.

3. A device for synchronous powder-feeding space laser cladding and three-dimensional forming, which characterized in, comprising an inside-laser powder-feeding nozzle, a laser generator, a mechanical arm, a control module, a transmission fiber, a gas-carried powder feeder and a gas source; the control module is connected with the mechanical arm, the laser generator, and the gas-carried powder feeder, respectively, the inside-laser powder-feeding nozzle is fixed at the front end of the mechanical arm, and the laser output of the laser generator is connected via the transmission fiber to the upper end of the inside-laser powder-feeding nozzle; a gas-supplying branch of the gas source is in communication with the gas-carried powder feeder, which is in communication with a powder spray tube in the inside-laser powder-feeding nozzle, with a collimating gas tube sleeved outside the powder spray tube; another gas-supplying branch of the gas source is in communication via a tube with the collimating gas tube in the inside-laser powder-feeding nozzle.

4. The device for synchronous powder-feeding space laser cladding and three-dimensional forming according to claim 3, wherein the pressure of the gas-carried powder sprayed out of the powder spray tube is between 0 to 0.2 Mpa.

5. The device for synchronous powder-feeding space laser cladding and three-dimensional forming according to claim 3, wherein the pressure of the annular collimating gas sprayed out of the collimating gas tube is between 0.05 to 0.3 Mpa.

6. The device for synchronous powder-feeding space laser cladding and three-dimensional forming according to claim 3, wherein the ratio of the diameters of the powder spray tube and the collimating gas tube is 1:2 to 1:6.

7. The device for synchronous powder-feeding space laser cladding and three-dimensional forming according to claim 3, wherein the outlet of the powder spray tube extends beyond the outlet of the collimating gas tube by a length of 0 to 20 mm.

8. The device for synchronous powder-feeding space laser cladding and three-dimensional forming according to claim 3, wherein the gas outputted from the gas source is an inert gas.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a schematic diagram of an existing outside-laser powder-feeding nozzle in the background of the invention.

[0025] FIG. 2 is a schematic diagram of an existing inside-laser powder-feeding nozzle in the background of the invention.

[0026] FIG. 3 is a schematic diagram of the horizontal layered dislocation of the existing curved boundary in the background of the invention.

[0027] FIG. 4 is a schematic diagram of the connection of the device for synchronous powder-feeding space laser cladding and three-dimensional forming of the present invention in Example 1.

[0028] FIG. 5 is a diagram of the relation between the powder spray tube and the collimating gas tube of the present invention in Example 1.

[0029] FIG. 6 is a schematic diagram of the method for forming unit by unit a multi-branch structural part of the present invention in Example 2.

[0030] FIG. 7 is a schematic diagram of the unit zoning forming method of the present invention in Example 3.

[0031] FIG. 8 is a schematic diagram of the normal layering forming method of the curved boundary of the present invention in Example 3.

[0032] FIG. 9 is a schematic diagram of the solid forming method of the multiple boundary regions of the present invention in Example 4.

[0033] FIG. 10 is a schematic diagram of the solid forming method of the boundary face with the same degree of curvature of the present invention in Example 5.

[0034] FIG. 11 is a schematic diagram of the method for forming a thin-walled rotating part of the present invention in Example 6.

[0035] FIG. 12 is a schematic diagram of the method for repairing defects on the base surface with any inclination of the present invention in Example 7.

[0036] List of reference signs: 1. An inside-laser powder-feeding nozzle; 2. a gas source; 3. a gas-carried powder feeder; 4. a control module; 5. a transmission fiber; 6. a laser generator; 7. a mechanical arm; 8. a forming part; 9. a powder spray tube; 10. a collimating gas tube; 11. a forming unit a; 12. a forming unit b; 13. a forming unit c; 14. gas-carried powder; 15. annular collimating gas; 16. a filling region; 17. a boundary face; 18. a boundary region; 19. a base surface; 20. a rotary table; 21. a surface to be repaired; 22. a laser beam; and 23. a powder beam.

DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention will be further described below with reference to drawings and examples.

EXAMPLE 1

[0038] A method for synchronous powder-feeding space laser cladding and three-dimensional forming is provided, comprising the following steps:

[0039] (1) Dividing a multi-branch complex three-dimensional solid expected to be formed into one or more forming units based on the body simplification and nozzle cladding scanning accessibility principle, and selecting the forming sequence of each unit in turn, with each forming unit having a respective optimal forming growth direction and rule;

[0040] (2) dividing the forming unit obtained in the step (1) into a number of layers along the stacking accumulating direction, each layer at least including one of the filling region and the boundary region;

[0041] (3) using a hollow annular laser inside-laser single-beam gas-carried powder-feeding method to control a mechanical arm to drive an inside-laser powder-feeding nozzle to scan and move in the boundary region and the filling region of a layer along a predetermined track, so as to complete cladding accumulating forming of this layer, respectively; in scanning forming, the laser-powder spray axis of the inside-laser powder-feeding nozzle is always along the normal direction of the layer; when the filling region and the boundary region are inconsistent in the slicing direction, i.e., the layers are not parallel to each other, the nozzle may need to be deflected to complete cladding forming of the different regions, respectively;

[0042] (4) after cladding forming of a layer, the nozzle can retreat by a distance of thickness of one layer along the growth direction of a next layer, and completes scanning cladding forming of a new layer according to the step (3); the nozzle needs to get its position continuously changed in forming the boundary region of each layer, stacking forming always along the bending direction of the boundary, with the upper and lower layers all covered without dislocation, avoiding the laser-powder leakage caused by a stacking fault, removing the “step effect”; repeating in this way, until the stacking accumulation of the entire forming unit is completed; and

[0043] (5) after completing a forming unit, controlling the mechanical arm to move the inside-laser powder-feeding nozzle to the start position of a next forming unit, so as to repeat the steps (2), (3) and (4) for stacking accumulating forming of a new forming unit; repeating in this way, until completing all the unit accumulation of the entire three-dimensional solid.

[0044] In this example, the layering principle of the boundary region is as follows: Slicing along the vertical direction, i.e. the normal direction of the boundary face. When the boundary face is straight faced, the layers are parallel to each other and equal in thickness; when the boundary face is a curved surface, the layers can be neither parallel to each other nor equal in thickness. The layering principle of the filling region is as follows: The layers are all parallel to the base surface and also parallel to each other.

[0045] As shown in FIGS. 4 and 5, a device for synchronous powder-feeding space laser cladding and three-dimensional forming is provided, comprising an inside-laser powder-feeding nozzle 1, a laser generator 6, a mechanical arm 7, a control module 4, a transmission fiber 5, a gas-carried powder feeder 3 and a gas source 2; the control module 4 is connected with the mechanical arm 7, the laser generator 6 and the gas-carried powder feeder 3, respectively, and controls movement of the mechanical arm 7; the inside-laser powder-feeding nozzle 1 is fixed at the front end of the mechanical arm 7, and can move in the space with the mechanical arm 7, so as to form on any angular base surface in the space and continuously change position and pose for cladding forming according to the path plan given by the control module 4, thus producing a forming part 8. The laser output of the laser generator 6 is connected via the transmission fiber 5 to the upper end of the inside-laser powder-feeding nozzle 1; a gas-supplying branch of the gas source 2 is in communication with the gas-carried powder feeder 3, which is in communication with a powder spray tube 9 in the inside-laser powder-feeding nozzle 1, so as to transport the gas-carried powder 14; with a collimating gas tube 10 sleeved outside the powder spray tube 9, another gas-supplying branch of the gas source 2 is in communication via a tube with the collimating gas tube 10 for transporting the annular collimating gas 15.

[0046] In this example, the pressure of the gas-carried powder 14 sprayed out of the powder spray tube 9 can be adjusted to 0-0.2 Mpa, the pressure of the annular collimating gas 15 sprayed out of the collimating gas tube 10 can be adjusted to 0.05-0.3 Mpa, the ratio of the diameters of the powder spray tube 9 and the collimating gas tube 10 is 1:2-1:6, the outlet of the powder spray tube 9 extends beyond the outlet of the collimating gas tube 10 by a length of 0-20 mm, and the gas outputted from the gas source 2 is an inert gas.

EXAMPLE 2

[0047] As shown in FIG. 6, dividing the three-branch three-dimensional forming into three simple-shaped forming units a, b and c according to the body simplification and inside-laser powder-feeding nozzle accessibility principle; wherein the forming unit a11 has a forming growth direction a1, the forming unit b12 has a forming growth direction b1, and the forming unit c13 has a forming growth direction c1. The forming sequence is as follows: First forming the forming unit a11, then controlling the mechanical arm 7 to move the inside-laser powder-feeding nozzle 1 to the start position of the forming unit b12 to form the forming unit b12 on the sidewall of the forming unit a11, and then controlling the mechanical arm 7 to move the inside-laser powder-feeding nozzle to the start position of the forming unit c13 to form the forming unit c13 on the other side of the forming unit a11, and so on, until completing the unit accumulation of the entire three-branch three-dimensional solid.

EXAMPLE 3

[0048] The synchronous powder-feeding space laser cladding and three-dimensional forming of the curved overhanging structural part is shown in FIGS. 7 and 8, which uses a zoning method, dividing the forming unit along the optimal growth accumulation direction into a number of layers, with each layer divided into a boundary region 18 and a filling region 16. The layering principle of the boundary region 18 is as follows: Always slicing along a direction perpendicular to the boundary face 17, i.e. along the normal direction of the boundary face; when the boundary face is straight faced, the layers are parallel to each other; when the boundary face is a curved surface, the layers can be neither parallel to each other nor equal in thickness. The layering principle of the filling region 16 is as follows: All the layers are parallel to the base surface 19 and also parallel to each other. After cladding forming a layer, the nozzle retreats by a distance of thickness of one layer along the growth direction of the layers, so as to complete scanning cladding forming of a new layer. Repeating in this way, until the stacking accumulation of the entire forming unit is completed. For the curved boundary region 18, the position of the nozzle needs to be continuously changed for forming each layer, and stacking forming is carried out always along the normal direction of the boundary. The zoning forming method can make the upper and lower layers entirely covered without dislocation, avoid the laser-powder leakage caused by a stacking fault, and remove the “step effect”.

EXAMPLE 4

[0049] In Example 3 as shown in FIG. 9, the forming unit can include one or more boundary faces 17, i.e. including one or more boundary regions 18.

EXAMPLE 5

[0050] As shown in FIG. 10, when multiple boundary faces 17 of the forming unit are parallel to each other or have the same degree of curvature, the filling region 16 can be consistent with the boundary region 18 in the layering direction, that is, both the filling region 16 and the boundary region 18 are based on the layering principle of always layering along a direction perpendicular to the boundary face 17, i.e. along the normal direction of the boundary face.

EXAMPLE 6

[0051] As shown in FIG. 11, for the synchronous powder-feeding space laser cladding and three-dimensional forming of the thin-walled rotating part, the part is only divided into the boundary region 18 according to characteristics of the thin-walled structure, layered along the vertical direction of the curved boundary face 17. Controlling the mechanical arm 7 to retain the inside-laser powder-feeding nozzle 1 to the normal direction of the boundary face for cladding forming, meanwhile driving the base surface 19 to rotate by the rotary table 20 by accumulating one layer per revolution, and then controlling the mechanical arm 7 along the predetermined track to retain the inside-laser powder-feeding nozzle 1 to retreat by a distance of thickness of one layer for accumulating a next layer, until the stacking accumulation of the entire thin-walled rotating part is completed.

EXAMPLE 7

[0052] As shown in FIG. 12, for the space laser cladding and three-dimensional forming repair method for the damaged parts on the base surface with any inclination, layering the filling region 16 by taking the damaged part of the surface 21 to be repaired as the filling region 16, with all the layers parallel to the surface 60 to be repaired. Controlling the mechanical arm 7 to retain the inside-laser powder-feeding nozzle 1 to complete cladding forming of a layer, and then controlling the mechanical arm 7 along the predetermined track to retain the inside-laser powder-feeding nozzle 1 to retreat by a distance of thickness of one layer for accumulating a next layer, until completing stacking filling accumulating repairing forming of the entire damaged part.