A welding torch that automatically adjusts the focus in manual laser welding operations

Abstract

The invention relates to a welding torch that automatically adjusts the focus in manual laser welding operations. The invention particularly relates to a welding torch used in laser welding applications that automatically adjusts the position of the focal point of the laser beam on the workpiece depending on the angular change made by manual laser welding torch with the workpiece surface.

Description

[0001] A WELDING TORCH THAT AUTOMATICALLY ADJUSTS THE FOCUS IN MANUAL LASER WELDING OPERATIONS

[0002] Technical Field

[0003] The invention relates to a welding torch (or welding gun) that automatically adjusts the focus in manual laser welding operations.

[0004] The invention particularly relates to a welding torch used in laser welding applications that automatically adjusts the position of the focal point of the laser beam on the workpiece depending on the angular change made by manual laser welding torch with the workpiece surface.

[0005] State of the Art

[0006] Manual laser welding operation is a welding method used for joining metal parts. This operation is based on concentrating heat between the parts to be joined, focusing on the metal surface of a laser beam. Manual laser welding is a preferred method of joining parts with particularly precise and complex geometry and is performed using a welding torch (gun).

[0007] Among the many parameters that affect the welding quality in the laser welding operation, the angle at which the laser beam hits the material and the depth of the focus of the laser beam on the material are two important variable parameters. Since the welding torch is used by an operator in manual welding operations, the hand skills of the operator are of great importance in obtaining a standard quality welding. Standardizing the welding quality not only ensures that the desired quality is achieved continuously, but also reduces the number of discarded parts that are discarded due to faulty production. In current applications, there is no support system to reduce operator induced errors.

[0008] During the laser welding operation, the weld pool profile in the region that melts and resolidifies varies according to the position of the focal point, which changes depending on the angle at which the laser beam hits the material. Changing the focal point, especially the type, thickness, reflectivity and thermal conductivity of the material to be welded, shows that it is necessary to obtain optimum weld seam quality. While the adjustment of the focal point can be carried out with high accuracy in robotic and CNC machine applications, the change in the angular position of the manual laser welding device operating in contact with the work material to be welded in manual welding operations changes the focal point.

[0009] Since the manual laser welding torch works closely by contacting the material, welding at steep angles is not preferred since there is a risk that the laser beam reflected from the material surface will enter the torch and damage the optical elements. Additionally, steep angles will block the torch nozzle, preventing the flow of gas that protects the lens. Since high-temperature microsplatters can enter and adhere to the lens when there is no gas flow in the nozzle, manual welding is done by keeping the tip at a certain angle while touching the surface and leaving enough clearance to allow gas flow. This clearance increases as the torch is tilted toward the surface. However, this changes the focus, and therefore, the quality of the source changes.

[0010] In current applications, especially when spot welding is to be made, the shape of the weld pool has a significant effect on the mechanical strength of the joined parts. Factors such as the angle at which the laser beam hits the material and the depth of the weld pool depend on the angle between the welded material and the laser beam, but the change of this angle causes positive and negative effects. This effect was previously studied by Reis et al. and an auxiliary device was developed to adjust the angular position. However, there is no device in the literature that automatically corrects the focus adjustment due to angular error.

[0011] The patent application numbered TR2022 / 021077 titled " Intelligent Hand Welding Torch System and Method for Manual Laser Welding” is a smart hand welding torch system for manual laser welding used in laser welding applications and comprises an angular position sensor that continuously measures the angle of the torch according to the welded surface at certain time intervals, a welding torch head that allows the laser beam I manual welding torch to be made perpendicular to the welding surface before the manual laser welding operation, a measurement button that allows the manual welding torch to become perpendicular to the welding surface through the welding torch head, a control card that calculates the suitability of the angle between the welding surface and the laser beam according to the angle data measured by the angular position sensor and allows the user to be warned by means of led or auditory stimulation. In the relevant application, there is no teaching that the focal point can be adjusted automatically. Laser power and duration applied to the material are essential parameters for obtaining spot welds with strong mechanical strength and visually desired shapes. In normal cases, changing the torch angle too much is impossible. Once the angle between the material surface and the torch changes, the focal point begins to rush away from the material surface. The energy density and its effect on the material are reduced by scattering the laser beam. Therefore, using angle as a variable parameter is inefficient. It is possible to adjust the laser's focus on the material at different angles. In that case, adjusting it with a new parameter that will increase the welding quality will be possible.

[0012] In current applications, the manual laser welding torch tip (gun tip) has a screw mechanism. One turn of the screw gun tip extends or shortens the gun tip to the screw pitch. The operator can manually adjust the tip length, that is, the focus, by turning the screw mechanism.

[0013] As a result, due to said disadvantages and the insufficiency of the current solutions regarding the subject matter, a development is required to be made in the relevant technical field.

[0014] Objective of the Invention

[0015] The object of the invention is to solve said disadvantages by being inspired from the current situations.

[0016] The main object of the invention is to enable automatic adjustment of the position of the focal point of the laser beam on the workpiece depending on the angular change made by the welding torch with the material surface.

[0017] Another object of the invention is to provide a focus in the region below the material surface (negative focus) or a focus in a region above the material surface (positive focus) if the focal point is desired.

[0018] Another object of the invention is to provide ease of use for operators with the buttons and visual information display on it.

[0019] Another object of the invention is to prevent possible operator errors by eliminating the use of the threaded nozzle tip structure. A welding torch that automatically adjusts the focus of the laser beam on the workpiece to perform the welding operation according to the grip angle during manual laser welding on a workpiece in order to achieve said objects, comprising the following:

[0020] • a collimator lens located in the interior of said welding torch body to enable the collimation of said laser beam entering said welding torch,

[0021] • a focusing lens for enabling the laser beam emanating from said collimator lens to focus at one point,

[0022] • an outlet chamber located at the end of said welding torch,

[0023] • a movable nozzle positioned at the end of said outlet chamber to enable said laser beam focused in said focusing lens to pass through said outlet chamber and reach over said workpiece,

[0024] • an information display showing the active length of said movable nozzle to the operator,

[0025] • a gear mechanism capable of translating rotational motion into linear motion and is positioned on the inner walls of said outlet chamber to enable said movable nozzle to move linearly,

[0026] • a focus adjustment motor that provides rotational motion to said gear mechanism,

[0027] • focus adjustment buttons controlling said focus adjustment motor,

[0028] • a pressure sensor located in said outlet chamber for measuring the variation of the pressure of the shielding gas in said outlet chamber relative to the width of the shielding gas outlet range at said movable nozzle end depending on the position of said movable nozzle on said workpiece surface,

[0029] • a control unit comprising software for reading analog signal information received from said pressure sensor and determining the openness and closedness ratio at the outlet of said movable nozzle to calculate the angle of said movable nozzle relative to the surface of said workpiece and the deviation in the predetermined position of said focal point; determining, in accordance with its calculations, how far said movable nozzle should move forward or backward to correct the deviation in the predetermined position of said focal point and sending a command to said focus adjustment motor to move said gear mechanism,

[0030] The structural and characteristic features and all the advantages of the invention will be understood more clearly by means of the figures and the detailed description with reference to these figures provided below and therefore, the evaluation should be made by taking these figures and the detailed description into consideration.

[0031] Figures for a Better Understanding of the Invention

[0032] Figure 1 is isometric view of the welding torch.

[0033] Figure 2 is sectional view of the welding torch.

[0034] Figure 3 is sectional view of the lengths used in the calculations.

[0035] Figure 4 is sectional view showing the stroke of the movable nozzle and the focal point of the laser beam on the workpiece.

[0036] Figure 5 is sectional view showing the stroke of the movable nozzle, the flow of the shielding gas, and the openness-closedness ratio at the outlet of the movable nozzle.

[0037] Figure 6 is sectional view showing the backward movement of the movable nozzle from its position in Figure 4 due to changes in the grip angle of the welding torch.

[0038] Figure 7 is sectional view showing the changes in the flow of shielding gas and the openness-closedness ratio at the outlet of the movable nozzle due to changes in the grip angle of the welding torch compared to Figure 5.

[0039] Descriptions of Part References

[0040] Detailed Description of the Invention

[0041] In this detailed description, the preferred embodiments of welding torch (1 ) of the invention are described only for a better understanding of the subject.

[0042] The welding torch (1 ) of the invention is manually triggered equipment that focuses laser beam (12), which is the focused electromagnetic radiation that will perform the welding operation. The welding torch (1 ) is handled by an operator by holding the grip (16). The generated laser beam (12) to be used in the welding torch (1 ) is carried to the welding torch (1 ) with a fiber optic cable (9). At the point where the cable (9) is connected to the welding torch (1 ), there is also a tube (not shown in the figures) carrying the shielding gas to ensure that the shielding gas is supplied.

[0043] The laser beam (12) carried by the cable (9) to the welding torch (1 ) passes through a collimator lens (6) located inside the body of the welding torch (1 ). The collimator lens (6) allows the laser beam (12) to be collimated before focusing.

[0044] The laser beam (12) emanating from the collimator lens (6) reaches to a focusing lens (8). The focusing lens (8) functions to focus the laser beam (12) to a single point. Said collimator lens (6) and the focusing lens (8) are fixed to the inner wall of the welding torch (1 ) body with a lens mount (7).

[0045] The laser beam (12) focused on the focusing lens (8) passes through the outlet chamber (17) at the end of the welding torch (1 ) and reaches the workpiece (10) to be welded through a movable nozzle (13). The movable nozzle (13) is positioned at the end of the outlet chamber (17) and can move linearly. The movable nozzle (13) is connected to a gear mechanism (5) positioned on the inner walls of the outlet chamber (17). Said gear mechanism (5) is capable of converting the rotational motion into linear motion and enables the movable nozzle (13) to move linearly with the drive it receives from a focus adjustment motor (4). The stroke (e), which is the range in which the movable nozzle (13) can move, is shown in Figures 4 and 5.

[0046] There is a pressure sensor (2) in the outlet chamber (17) and said pressure sensor (2) measures the change of the pressure of the shielding gas in the outlet chamber (17) depending on the angular position of the movable nozzle (13) on the surface of the workpiece (10). This measurement process takes place according to the width of the shielding gas outlet range at the end of the movable nozzle (13). According to the change in pressure, the angle between the movable nozzle (13) and the surface of the workpiece (10) is calculated, and the deviation at the predetermined position of the focal point can be detected.

[0047] During the shielding gas flow, the analog signal information received from the pressure sensor (2) is transmitted to a control unit (3), and the control unit (3) reads this pressure value and determines the openness-closedness ratio at the outlet of the movable nozzle (13). This ratio allows the control unit (3) to calculate the angle of stop of the movable nozzle (13) relative to the surface of the workpiece (10). The control unit (3) also enables the calculation of the deviation at the predetermined distance between the focus and the sheet metal surface. The active length of the torch nozzle shown in Figure 3 is calculated with the \BF\ following equation.

[0048] Here, |XE| is the fixed focal length of the lens. |4C| is the distance between the focal point and the sheet metal surface. This value can be determined as negative, positive or zero by the user. |CD| is calculated using the following formula derived from right triangle relationships.

[0049] Here d, is the outer diameter of the cylindrical movable nozzle (13) and is equal to \DB |= d / 2.

[0050] Said calculation process takes place as a result of the digital processing of the analog pressure signal information from the pressure sensor (2) by a software located in the control unit (3). The control unit (3), based on its calculations, determines the movement that the movable nozzle (13) needs to make to correct the deviation from the predetermined position of the focal point and sends commands to the focus adjustment motor (4) to move the gear mechanism (5). Accordingly, the focus adjustment motor (4) is driven, and the gear mechanism (5) is rotated. The rotational motion of the gear mechanism (5) allows the nozzle (13) to reciprocate and the focal point to be adjusted. The changes in the grip angle of the welding torch (1 ) affect the shielding gas flow, the angle of the movable nozzle (13) with respect to the workpiece (10), the openness- closedness ratio at the outlet of the movable nozzle (13), and the focal points, as shown in Figures 4, 5, 6, and 7.

[0051] There is a welding button (1 1 ) on the welding torch (1 ) of the invention and pressing the said welding button (1 1 ) triggers the start of the welding operation.

[0052] Focus adjustment can be made manually on the operator side with the focus adjustment buttons (14) on the welding torch (1 ). Once the focus adjustment is set, the error due to the angular grip is automatically corrected by the control unit (3) by measuring the pressure in the outlet chamber (17).

[0053] With an information display (15) on the welding torch (1 ), values such as the focal position, the pressure of the gas outlet chamber (17) and the angle between the surface of the workpiece (10) and the movable nozzle (13) calculated using the pressure value can be shown to the operator. While the focal point is set manually, the linear position of the movable nozzle (13) can be shown to the operator on the information display (15) with numerical values or visual indicators.

[0054] The use and working principle of the welding torch (1) of the invention are as follows:

[0055] The movable nozzle (13) length (focus adjustment) of the welding torch (1 ) is made by the operator with the help of the focus adjustment buttons (14) controlling the focus adjustment motor (4). The correct setting can be found with experience or predetermined by the operator. The tip length (focus adjustment position) of the movable nozzle (13) is reflected in a digital or analog manner on the information display (15). With the help of the information display (15), the operator knows exactly the length of the movable nozzle (13). In this way, it is easier to make adjustments and to catch the predetermined movable nozzle (13) length. Once the focus adjustment is made, the invention is programmed to adjust itself to maintain this focal point at the same depth on the workpieces (10) to be welded, regardless of the grip angle of the welding torch (1 ). Before starting the welding operation, the movable nozzle (13), collimator lens (6), and focusing lens (8) channel, where the shielding gas exits freely from the open end, are cleaned and the pressure in the outlet chamber (17) is measured using a pressure sensor (2) with the press of the button (11 ) once in the idle state. In this way, both the potential dust in the lens channel is expelled and the minimum pressure value of the outlet chamber (17) is measured by the pressure sensor (2). With pressure measurement, the movable nozzle (13) warns the operator on the information display (15) by determining whether there is a possible obstruction or narrowing in the lens channel. Since any obstruction in the channel will complicate the flow, it causes the pressure value in the outlet chamber (17) to increase. Welding spatter can also frequently enter this channel, causing it to narrow. If the lens channel is narrowed by pollutants, it is cleaned before starting the welding operation and the refraction of the laser beam (12) in the narrowing channel is prevented. At the same time, it is ensured that the pressure value returns to the calibration value.

[0056] When the movable nozzle (13) contacts the surface of the workpiece (10) to be welded at different angles, there is a narrowing at the outlet depending on the grip angle of the welding torch (1 ). This narrowing complicates the shielding gas flow and causes the pressure value measured in the outlet chamber (17) to be higher than the pressure measured in the idle state (calibration pressure). The width of the output gap varies proportionally with the relative angle of the movable nozzle (13) to the surface of the workpiece (10). In this way, the extent to which the outlet of the movable nozzle (13) narrows from the pressure rise and then the relative angle between the movable nozzle (13) and the welding surface of the workpiece (10) is calculated by the control unit (3). With the pressure information received as an input to the processor in the control unit (3), it is calculated through the mathematical model how much the movable nozzle (13) attached to the end of the welding torch (1 ) should be in or how long it should be out so that the point where the laser beam (12) is focused is not displaced in the vertical plane. The motion control command signal required to move the movable nozzle (13) to this position is generated by means of the focus adjustment motor (5) and the gear mechanism (5). In this way, holding the manual laser welding torch (1 ) at different angles intentionally or unintentionally by the operator, especially in overlap welding type applications, will not have a negative effect on the welding quality. It is also possible for the welding quality improvement studies to focus not only on the material surface, but also elsewhere in the material, to the extent permitted by the range of motion in the axis in which the movable nozzle (13) is linearly bedded.

Claims

CLAIMS1. A welding torch (1 ) which automatically adjusts the focus of the laser beam (12) to perform the welding operation on workpiece (10) according to the grip angle during manual laser welding on said workpiece (10), characterized by comprising:• a focusing lens (8) for enabling said laser beam (12) to focus at one point,• an outlet chamber (17) located at the end of said welding torch (1 ),• a movable nozzle (13) positioned at the end of said outlet chamber (17) to enable said laser beam (12) focused on said focusing lens (8) to pass through said outlet chamber (17) and reach over said workpiece (10),• a gear mechanism (5) capable of translating the rotational motion into linear motion and positioned on the inner walls of said outlet chamber (17) to enable said movable nozzle (13) to move linearly,• a focus adjustment motor (4) that provides rotational motion to said gear mechanism (5),• a pressure sensor (2) in said outlet chamber (17) for measuring the variation of the pressure of the shielding gas in said outlet chamber (17) relative to the width of the shielding gas outlet gap at the end of said movable nozzle (13) depending on the position of said movable nozzle (13) on the surface of said workpiece (10),• a control unit (3) comprising a software for sending a command to the said focus adjustment motor (4) to move the said gear mechanism (5) by determining how far forward or backward the said movable nozzle (13) must move in order to correct the deviation at the predetermined position of the focal point and to calculate the deviation at the predetermined position of the focal point and the angle of stop of the said movable nozzle (13) relative to the surface of said workpiece (10) by reading the analog signal information received from said pressure sensor (2) and determining the openness and closedness ratio at the outlet of the said movable nozzle (13).

2. The welding torch (1 ) according to claim 1 , characterized by comprising grip (16) to allow said welding torch (1 ) to be held by hand.

3. The welding torch (1 ) according to claim 1 or 2, characterized by comprising a fiber optic cable (9) to move said laser beam (12) to said welding torch (1 ).

4. The welding torch (1 ) according to any of the preceding claims, characterized by comprising a tube which transports shielding gas in order to provide shielding gas feeding.

5. The welding torch (1 ) according to any of the preceding claims, characterized by comprising a collimator lens (6) which is located in the inner body of said welding torch (1 ) in order to ensure the collimation of said laser beam (12) that enters said welding torch (1 ).

6. The welding torch (1 ) according to any of the preceding claims, characterized by comprising lens mounts (7) that ensure that said collimator lens (6) and said focusing lens (8) are fixed on the inner wall of the body of said welding torch (1 ).

7. The welding torch (1 ) according to any of the preceding claims, characterized by comprising a welding button (1 1 ) which triggers the start of the welding operation.

8. The welding torch (1 ) according to any of the preceding claims, characterized by comprising focus adjustment buttons (14) which ensures that the focus adjustment can be made manually on the operator side.

9. The welding torch (1 ) according to any of the preceding claims, characterized by comprising information display (15) that uses numerical values or visual indicators to display the focal position, the deviation at the predetermined position of the focus, the length of the said movable nozzle (13), the pressure of said outlet chamber (17) and the angle value between said workpiece (10) surface and said movable nozzle (13) by calculations using pressure value.

10. The welding torch (1 ) according to any of the preceding claims, characterized in that said control unit’s (3) measurements are carried out with the following formulas:andwherein,\BF\, said movable nozzle (13) active length;|X£|, said focusing lens’ (8) fixed focal length;|XC|, the distance between the focus and the surface of said workpiece (10) to be determined by the user as negative, positive or zero; d, the outer diameter of the cylindrical movable nozzle (13) and is equal to \DB\= d / 2

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