Laser welding air management system with airflow-optimized deflector

Abstract

Air management systems are provided for optimizing air flow in laser welding using a deflector. A system for a welder includes a blower for generating an air flow. A plenum receives the air flow, directs it toward a workpiece, and defines an outlet facing the workpiece to discharge the air flow toward the workpiece. A deflector adjacent the outlet is formed as a tapered portion converging from the plenum toward the workpiece and is defined by an angled wall having a neutral opening. The deflector concentrates the air flow to impart an increase in velocity to the air flow after it exits the outlet and imparts a favorable directional component to the air flow toward the weld zone, as well as protects the laser lens by increasing the downward momentum force of the air flow to eliminate the possibility of spatter impacting the lens.

Description

Technical Field

[0001] This disclosure generally relates to laser welding, and more specifically, to airflow management and optimization in laser welding to avoid the effects of plume emissions in the welding zone, thereby positively impacting the weld quality of the workpiece. Background Technology

[0002] In laser welding, a high-density light source is used to melt the materials of the parts to be joined. Multiple parts are typically placed in contact with each other or with a gap of no more than a small gap at the joint interface between the parts. The laser beam passes through the joint interface via a welding machine to fuse the parts together. At the point where the laser beam intersects with the parts, a pool of molten material forms in the heated area, which mixes with the materials of the parts being joined.

[0003] In some forms of laser welding, both molten material and metal vapor can form. Metal vapor can displace areas of molten material in the weld pool, such as at the point where the laser beam enters the part. These displaced areas can be referred to as keyholes. Some material evaporation may occur, for example, as the material is heated to its boiling point by the high-density laser energy. As the evaporated material leaves the material surface, it creates a recoil pressure that pushes the melt surface, causing displacement. Small particles can be emitted as plumes of opaque material. These plumes can suppress the laser beam during its path to the workpiece. Metal vapor can also aggregate into larger particles, which, when approaching or exceeding the size of the laser beam wavelength, can significantly attenuate the laser power reaching the workpiece. The effects of plumes can include inconsistencies in the laser power reaching the material, which can lead to quality problems such as insufficient laser penetration, spatter, and cavities.

[0004] Therefore, it is desirable to provide a system for laser welding that effectively and efficiently overcomes the effects associated with plume formation and other emissions. Furthermore, other desirable features and characteristics of the invention will become apparent from the following detailed description and appended claims, taken in conjunction with the accompanying drawings and the foregoing technical and background information. Summary of the Invention

[0005] In various embodiments, systems with air management features are provided for laser welding to reduce the effects of plume formation and to optimize airflow using deflectors. In several embodiments, a system for a welding machine includes a blower to generate an airflow. An air chamber receives the airflow, directs it toward a workpiece, and defines an outlet facing the workpiece to discharge the airflow toward the workpiece. A deflector adjacent to the outlet is formed as a conical portion converging from the air chamber toward the workpiece and is defined by an angled wall with a neutral opening. The deflector concentrates the airflow to increase its velocity after it leaves the outlet and to impart a favorable directional component to the airflow toward the welding area.

[0006] In another embodiment, the deflector includes a smooth surface followed by the airflow, and the smooth surface is configured to reduce turbulence in the airflow.

[0007] In another embodiment, the angled wall of the deflector is set at an angle relative to the vertical direction in the range of approximately 35 to 40 degrees.

[0008] In another embodiment, the deflector extends from the top near the air chamber to the bottom away from the air chamber, wherein the top is radially positioned entirely inside the opening.

[0009] In another embodiment, the deflector extends from the top near the air chamber to the bottom away from the air chamber, wherein the top is radially positioned outside the opening.

[0010] In another embodiment, the deflector has a height of approximately three centimeters in the direction from the air chamber toward the workpiece.

[0011] In another embodiment, the deflector is formed by additive manufacturing, wherein the surface quality is configured to limit airflow friction.

[0012] In another embodiment, the welding machine is configured to generate a laser beam configured to follow a path. The gas chamber is an annular gas chamber with a neutral opening. The deflector is an annular deflector with its neutral opening aligned with the neutral opening of the gas chamber around the path of the laser beam.

[0013] In another embodiment, the deflector is connected to the air chamber via an airtight connector.

[0014] In another embodiment, the welding machine includes a fixing device with clamps configured to engage workpieces. The welding zone is defined between the clamps, and a deflector is configured to concentrate and direct airflow to a point between the clamps.

[0015] In several other embodiments, the welding machine is configured to weld a workpiece at a welding zone. A blower is configured to generate an airflow, and an air chamber is connected to the blower to receive and direct the airflow toward the workpiece. The air chamber defines an annular outlet configured to face the workpiece and discharge the airflow toward it. A deflector is disposed near the outlet and is formed as a tapered portion converging from the top near the air chamber to the bottom away from the air chamber. The deflector is defined by an annular wall with a neutral opening to concentrate the airflow, thereby imparting an increase in velocity to the airflow after it leaves the outlet and imparting a directional component toward the welding zone to the airflow.

[0016] In another embodiment, the deflector includes a smooth surface adjacent to the airflow. The airflow follows the smooth surface, and the smooth surface reduces turbulence in the airflow.

[0017] In another embodiment, the annular wall of the deflector is set at an angle of approximately 35 to 40 degrees relative to the vertical direction, and the deflector is axisymmetric.

[0018] In another embodiment, the top of the deflector is radially positioned entirely inside the opening.

[0019] In another embodiment, the top of the deflector is radially positioned outside the opening.

[0020] In another embodiment, the deflector has a height of no more than three centimeters from top to bottom.

[0021] In another embodiment, the deflector is formed from a rigid material by additive manufacturing, wherein the surface quality is configured to limit airflow friction.

[0022] In another embodiment, the welding machine generates a laser beam configured to follow a path. The gas chamber includes an annular gas chamber with a neutral opening. The deflector includes an annular deflector that also has a neutral opening. The neutral opening is aligned around the path of the laser beam, and the deflector extends radially inward beyond the gas chamber.

[0023] In another embodiment, the deflector is connected to the gas chamber via an airtight connector. The gas chamber is spaced apart from the welding machine by a gap, and the deflector is configured to induce a flow through the gap.

[0024] In several other embodiments, a system includes a welding machine configured to weld a workpiece at a welding zone. A blower is configured to generate an airflow. An air chamber is configured to receive the airflow and direct it toward the workpiece. The air chamber defines an annular outlet configured to face the workpiece and discharge the airflow toward it. A deflector is configured adjacent to the outlet. The deflector is formed as a conical portion converging from the air chamber toward the workpiece. The deflector is defined by a wall having a neutral opening. The wall is positioned at an angle of approximately 35 to 40 degrees relative to the vertical direction. The deflector is configured to concentrate the airflow to impart an increase in velocity to the airflow after it leaves the outlet and to impart a directional component toward the welding zone. The welding machine includes a clamping device configured to engage the workpiece. The welding zone is defined between the clamps, and the deflector is configured to concentrate and direct the airflow to a point between the clamps. Attached Figure Description

[0025] Exemplary embodiments will be described below in conjunction with the accompanying drawings, wherein the same reference numerals denote the same elements, and wherein:

[0026] Figure 1 These are schematic diagrams of laser welding systems according to various embodiments;

[0027] Figure 2 According to various embodiments Figure 2 A partial schematic diagram of a portion of a laser welding system, showing the gas chamber and deflector area;

[0028] Figure 3 It is generally based on various embodiments. Figure 2 The cross-sectional view taken by line 3-3 indicated in the figure;

[0029] Figure 4 According to various embodiments Figure 2 A partial schematic diagram of a portion of a laser welding system, showing the gas chamber and deflector area;

[0030] Figure 5 It is generally based on various embodiments. Figure 4 The cross-sectional view taken by line 5-5 indicated in the figure; and

[0031] Figure 6 According to various embodiments Figure 1 The diagram illustrates the welding process application of the laser welding system. Detailed Implementation

[0032] The following detailed description is merely exemplary in nature and is not intended to limit application or use. Furthermore, it is not intended to be bound by any express or implied theory presented in the foregoing technical field, background art, invention summary, or the following detailed description.

[0033] As disclosed herein, a system is provided that includes airflow optimization via an air management system that generates a plume-managed airflow during laser welding operations. In several embodiments, a forced and induced airflow is generated near the source of the laser beam of the welding machine. Deflectors concentrate the airflow, increase its velocity, give it a strong directional vector, and counteract airflow interference. The deflectors effectively and efficiently reduce the effects of plumes and other emissions generated above the welding zone. The resulting flow distribution consistently moves the plume away from the welding zone, avoiding laser energy loss due to the plume effect and improving weld quality. In several embodiments, the deflectors are configured as tapered sections, such as tapered converging nozzles. The deflectors reduce airflow turbulence and define an effective airflow direction. The generated airflow enhances protection for the laser's optical lenses and also increases the amount and magnitude of the airflow toward the welding zone, causing more plume to move away from the welding zone. Improvements of up to 25% in mass flow rate from the welding zone have been demonstrated. The results include improved weld quality.

[0034] refer to Figure 1The diagram illustrates a welding system 20 that employs aspects of generating optimized gas flow for high-quality weld production. Typically, the welding system 20 includes a welding machine 22, an air management system 24, and a workpiece 28. The welding machine 22 can be any of various types of welding machines, and in the current embodiment, it is a laser welding machine. Therefore, the welding machine 22 includes a light source 30, a reflector 32, optics 34, a power supply 36, and a controller 38. The light source 30 is powered and controlled by the power supply 36 and the controller 38 to generate light into a resonant cavity 40. The light is spread and then reflected by the reflector 32 through the optics 34 to appear as a focused beam 42 focused at a point on the workpiece 28. The welding machine 22 is configured to move the beam along a designated welding path on the workpiece 28. The air management system 24 may include an airflow module 25 disposed below the laser optics 34. In embodiments, the optics and airflow module may be held by a robotic arm / stand system 26. In some embodiments, such as automotive applications, the laser power used can range from 1 kW to 10 kW. The generator can be configured as a stand-alone device that stands on the floor, where an optical fiber delivers the laser from the laser generator to the laser optics 34 for laser welding.

[0035] The laser beam 42 is directed at the workpiece 28 and thus traverses an air space subjected to air movement and contaminant exposure. The workpiece 28 may be multiple components, for example, for joining at a joint interface 44. The laser beam 42 is directed at the joint interface 44, thereby creating a molten pool 50. In the current embodiment, keyhole laser welding is employed. As the high-energy-density laser beam 42 traverses along the joint interface 44, the molten pool 50 develops. The surface material directly struck by the beam is heated to its evaporation point and evaporates. As the metal vapor leaves the surface, it generates a recoil pressure that forces the underlying melt to leave, forming a deep and narrow cavity, referred to as a keyhole 52 penetrating the molten material. Near-surface plasma emission 54 may occur, and particles may flow out of the weld pool 50 and the keyhole 52, thus forming a plume 56. The plume 56 can inhibit the laser beam 42 from reaching the workpiece 28. It has been found that the characteristics of the plume 56 may be related to the velocity and direction of the surrounding airflow. It has been further found that the fixture of the welding machine 22 near the weld pool 50 produces an airflow profile that exacerbates the effect of the plume 56. For example, clamps 60, 62 used to hold workpiece 28 to maintain an acceptable gap size at the joint interface 44 can generate an airflow vector in the path guiding the plume 56 to the beam 42. Additionally, fixing devices such as clamps 60, 62 can block or redirect the airflow that concentrates the plume 56. It has also been found that beam damping from the plume 56 can cause varying laser power reduction at workpiece 28. Even with monitoring, the controller 38 may not be able to adjust to compensate for these variations. Therefore, consistently maintaining the keyhole 52 may not result in increased spatter, plume discharge during opening and closing, and could lead to reduced weld quality. Besides the damping of the beam 42 by the plume 56, spatter can blur or damage the optics 34 of the welding machine 22, which is therefore undesirable.

[0036] Therefore, to reduce the impact of the plume 56, the current embodiment employs an air management system 24 to generate an optimized airflow profile to effectively remove the plume 56 from the path of the beam 42, including overcoming any effects, such as those caused by the clamps 60, 62. The air management system 24 typically includes a blower 72, an air chamber 74, and a deflector 76. The blower 72 generates a pressurized airflow delivered to the air chamber 74. The blower 72 can have various configurations, such as a motor-driven squirrel-cage centrifugal fan or other arrangements. The air chamber 74 can be a closed annular configuration and can completely surround the beam 42 near the exit of the beam 42 from the optics 34. The air chamber 74 has a neutral opening 78 through which the beam 42 can pass. The pressurized airflow, along with the induced airflow drawn in through the gap 78, is discharged through the deflector 76 as a flow 80 toward the workpiece 28. The flow 80 is optimized to disperse the plume 56 outside the path of the beam 42 and away from the welding area, thereby reducing or eliminating the effects of the unwanted plume 56. For example, flow 80 is generated as a vector with sufficient velocity and uniform directional intensity to redirect plume 56. Furthermore, flow 80 is directed over a relatively small region of interest, which increases the downward momentum force of airflow 80 and overcomes airflow disturbances, such as those caused by stationary or turbulent flow. As a result, optics 34 is protected from contamination, and the airflow in the welding zone is beneficially guided for better quality laser welding.

[0037] refer to Figure 2 The schematic diagram shows the area of ​​the air management system 24 facing the workpiece 28 (i.e., Figure 1 (At the bottom of the air management system 24). Blower 72 directs airflow into air chamber 74 via duct 82. Air chamber 74 is typically annular in shape with a neutral opening 79. See also... Figure 3 Air chamber 74 defines cavity 84, conduit 82 guides airflow into cavity 84, and air chamber 74 includes outlet 86 pointing toward workpiece 28. In the current embodiment, outlet 86 is in the form of an annular groove through which airflow is guided generally downward toward workpiece 28. Deflector 76 is attached to or integrally formed with air chamber 74 near outlet 86 and at or near its bottom surface 88.

[0038] The deflector 76 is shaped as a tapered portion defined by an annular wall 90 and can be described as a tapered converging nozzle having an open center 89 aligned with the neutral opening 79 of the air chamber 74. The annular wall 90, having an inner surface 92 and an outer surface 94, is formed of a relatively thin material. The bottom 96 of the deflector 76 has a smaller diameter than the top 98 of the deflector 76, thereby drawing the airflow 80 toward the beam 42. In this embodiment, the deflector 76 is positioned slightly above the bottom surface 88, such that the outlet 86 is located radially outward of the deflector 76. Therefore, the airflow 80 exiting the outlet 86 passes along the outer surface 94 of the deflector 76. As the flow 80 passes through the bottom 96 of the deflector 76, additional induced airflow 100 is drawn through the gap 78, thus joining the flow 80.

[0039] The deflector 76 is positioned at or near the bottom of the air chamber 74, with its top 98 adjacent to the interior 102 of the outlet 86 and positioned close to the air chamber 74. The bottom 96 of the deflector 76 is positioned away from the air chamber relative to the top 98. This allows the area of ​​the outlet 86 to be fully open from its interior 102 to its exterior 104 and unobstructed all the way to the workpiece 28. The proximity of the deflector 76 to the outlet 86 optimizes the deflector's ability to define the characteristics of the flow 80 as it is directed to the workpiece 28. This capability is improved by providing an airtight joint 106 between the top 98 of the deflector 76 and the air chamber 74. Furthermore, the deflector 76 generates optimized airflow by having a height 108 of three centimeters or approximately three centimeters from the top 98 to the bottom 96, and has an axisymmetric shape to generate an axisymmetric flow 80. The height 108 is chosen to minimize airflow loss due to friction on the wall 90. The material of deflector 76 is chosen to have surface qualities that limit friction and provide laminar flow, where air flows efficiently and its velocity increases smoothly across the boundary layer. The material of deflector 76 can be plastic, metal, or polymer, exhibiting a smooth inner surface 92 to reduce turbulence and a sufficiently rigid form to maintain its shape under applied airflow. In several embodiments, deflector 76 can be economically manufactured using additive manufacturing processes.

[0040] refer to Figure 4 and Figure 5 An alternative arrangement of the deflector 76 is shown. In this configuration, the deflector is positioned such that the top 98 of the wall 90 is at the bottom surface 88, radially outward from and adjacent to the outer edge 104 of the outlet 86. Other properties of the deflector 76 are similar to... Figure 2 and Figure 3The properties of the arrangement are the same or similar. The deflector 76 is again shaped as a converging nozzle, with its neutral opening 89 aligned with the neutral opening 79 of the air chamber 74. The deflector 76 is formed of a relatively thin material by an annular wall 90 having an inner surface 92 and an outer surface 94. The bottom 96 of the deflector 76 has a smaller diameter than the top 98 of the deflector 76, thereby guiding the airflow 80 toward the beam 42. In this embodiment, the deflector 76 is disposed at the bottom surface 88 such that the outlet 86 is disposed radially inward of the deflector 76. Therefore, the airflow 80 exiting the outlet 86 passes along the inner surface 92 of the deflector 76. As the flow 80 passes through the deflector 76, an additional induced airflow 100 is drawn through the gap 78, thereby incorporating into the flow 80.

[0041] The deflector 76 is positioned at the bottom of the air chamber 74 such that its top 98 is positioned adjacent to the outer 104 of the outlet 86. This positions the deflector 76 between the outlet 86 and the workpiece 28 in the region from its interior 102 to its exterior 104. The proximity of the deflector 76 to the outlet 86 optimizes the deflector's ability to define the characteristics of the flow 80 as it is directed toward the workpiece 28. This capability is further enhanced by providing an airtight joint 106 between the top 98 of the deflector 76 and the air chamber 74. Furthermore, the deflector 76 generates optimized airflow by having a height 108 of three centimeters, or approximately three centimeters, from its top 98 to its bottom 96, and an axisymmetric shape to produce an axisymmetric flow 80. The height 108 is chosen to minimize airflow losses due to friction on the wall 90. The material of the deflector 76 is selected to provide laminar flow, where air flows at a velocity that increases effectively and smoothly at the boundary layer. The material can be plastic, metal, or polymer, exhibiting a smooth inner surface 92 to reduce turbulence, and having a sufficiently rigid form to maintain its shape under an applied airflow. Similarly, the deflector 76 can be economically manufactured using an additive manufacturing process.

[0042] refer to Figure 6 The welding machine 22 has a fixing device 110 including clamps 60 and 62. The welding zone 112 is defined between clamps 60 and 62 and at the workpiece 28. The interior of the deflector 76 ( Figure 2-3 ) and external ( Figure 4-5The positions are optimized to guide the airflow 80 to the welding zone 112. In each case, the deflector 76 extends radially inward beyond the air chamber 74. Specifically, the flow 80 is guided between fixtures 60 and 62 and along and around the beam 42. By including the deflector 76, a gain of up to 25% in mass flow rate from the welding zone has been demonstrated. The wall 90 of the deflector 76 is angled / conical, such that it is set at an angle 114 relative to the vertical direction 116. The angle 114 is consistent around the perimeter of the deflector 76 and can be in the range of 35 to 40 degrees (35° to 40°) relative to the vertical direction 116. In one embodiment, the flow 80 is optimized to have an angle 114 of thirty-seven and a half degrees (37.5°). These parameters have been found to effectively disperse and redirect the plume 56 away from the welding zone 112 and away from the path of the beam 42.

[0043] Therefore, the system includes a laser welder with an airflow management system that effectively avoids plume and spatter effects, resulting in high-quality welds. Forced and induced airflow can be generated near the source of the laser beam in the welder. Deflectors concentrate the generated airflow, increasing its velocity and giving it a strong directional vector. The effects of airflow disturbances such as turbulence are overcome to reduce the impact of plumes generated above the weld area. The airflow management system amplifies and directs the airflow to the weld area and deflects the plumes. This provides consistent laser energy input to the workpiece and consistent weld quality.

[0044] While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be understood that numerous variations exist. It should also be understood that the one or more exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of this disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing one or more exemplary embodiments. It should be understood that various changes can be made to the function and arrangement of the elements without departing from the scope of this disclosure as set forth in the appended claims and their legal equivalents.

Claims

1. A system for a welding machine, the welding machine being configured to weld a workpiece at a welding zone, the system comprising: Welding machine; A blower, the blower being configured to generate an airflow; An air chamber, the air chamber defining a cavity configured to receive the airflow and the air chamber defining an outlet configured to direct the airflow toward the workpiece, the air chamber defining a structure defining a cavity having an outlet configured to face the workpiece and discharge the airflow toward the workpiece, the air chamber being spaced apart from the welding machine by a gap; A deflector, disposed adjacent to the outlet, is formed as a conical portion defined by an angled wall converging from the air chamber toward the workpiece. The deflector is also defined by an angled wall having a neutral opening. The deflector is positioned at the bottom of the air chamber, with the converging portion extending from the air chamber toward the workpiece. The deflector is positioned downstream of the outlet in the airflow, such that the airflow exits the chamber through the outlet before reaching the deflector. The angled walls of the deflector are configured to concentrate the airflow generated by the blower and induce the induced airflow to pass through the gap and enter the neutral opening. The induced airflow merges with the airflow generated by the blower within the deflector to form a combined flow. The angled walls of the deflector increase the velocity of the combined flow after the airflow leaves the outlet and impart a directional component toward the welding area to the combined flow, and are configured to induce the induced airflow through the gap.

2. The system according to claim 1, wherein, The deflector includes a smooth surface that the airflow follows, the smooth surface being configured to reduce turbulence in the airflow.

3. The system according to claim 1, wherein, The angled wall of the deflector is set at an angle of 35 to 40 degrees relative to the vertical direction.

4. The system according to claim 1, wherein, The top of the deflector is radially disposed inside the opening.

5. The system according to claim 1, wherein, The top of the deflector is radially positioned outside the opening.

6. The system according to claim 1, wherein, The deflector has a height of three centimeters in the direction from the air chamber toward the workpiece.

7. The system according to claim 1, wherein, The deflector is formed by additive manufacturing, wherein the surface quality is configured to limit airflow friction.

8. The system according to claim 1, wherein: The welding machine is configured to generate a laser beam, the laser beam being configured to follow a path. The air chamber includes an annular air chamber with a neutral opening. The deflector is a ring-shaped deflector with a neutral opening, and The neutral opening of the gas chamber and the neutral opening of the deflector are aligned around the path of the laser beam.

9. The system according to claim 1, wherein, The deflector is connected to the air chamber via an airtight connector.

10. The system according to claim 1, wherein: The welding machine includes a fixing device having a first clamp configured to engage the workpiece and a second clamp configured to engage the workpiece. The welding area is defined between the first clamp and the second clamp, and The deflector is configured to focus and direct the airflow to a point between the first clamp and the second clamp.

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