Electron beam welding scanning waveform dynamic regulation method and device

Abstract

The application provides an electron beam welding scanning waveform dynamic regulation method and device, the method comprises the following steps: pre-reading a welding numerical control program, obtaining a welding motion trajectory, and generating a pre-stored trajectory point set based on the welding motion trajectory; in the welding process, the current welding position is acquired in real time; based on the current welding position and the pre-stored trajectory point set, the current motion direction of the welding is determined; according to the current motion direction, the direction of the electron beam scanning waveform is dynamically adjusted, so that the extension direction of the scanning waveform matches the current motion direction. The device provided by the application can be configured on an electron beam welding equipment, and the scanning waveform parameters during electron beam welding are dynamically adjusted by the method, the welding seam forming quality is optimized, and the device is suitable for high-precision and high-complexity welding scenes.

Description

Technical Field

[0001] This invention relates to the field of electron beam welding technology, and more specifically, to a method and apparatus for dynamic control of electron beam welding scanning waveform. Background Technology

[0002] Vacuum electron beam welding is a high-energy beam welding technology that uses a high-speed, focused electron beam to bombard a workpiece, causing it to melt locally and form a weld. It features high energy density, a large weld depth-to-width ratio, and minimal thermal deformation, and is widely used in the welding of precision components in aerospace, nuclear energy, and military industries.

[0003] In existing vacuum electron beam welding equipment, the control of electron beam deflection scanning (i.e., applying a specific waveform to make the electron beam oscillate periodically near the welding point) mostly adopts a preset waveform mode. The specific workflow is as follows: Before welding, the operator or CNC system selects a fixed scanning waveform (such as circular, sinusoidal, figure-eight, etc.) from the waveform library in the equipment's memory and presets the corresponding digital waveform data. At the start of welding, the control system reads this waveform data at a fixed frequency, converts it into an analog voltage signal via a digital-to-analog converter (DAC), amplifies it by a power amplifier, and then drives the deflection scanning coil of the electron gun. The alternating magnetic field generated by the coil controls the electron beam to repeatedly scan along a preset fixed trajectory.

[0004] However, this control method with a fixed preset waveform has significant limitations: 1. Mismatch between scanning direction and welding motion direction: During electron beam welding, the electron gun is usually stationary while the workpiece moves. When the welding trajectory is curved (such as an arc or S-curve) or has corners, the workpiece's motion direction changes in real time. The fixed scanning waveform's spatial orientation (extension direction) is static in the workpiece coordinate system and cannot rotate synchronously with the workpiece's motion direction. This causes the electron beam's scanning energy to be unable to be symmetrically distributed along the instantaneous weld centerline. High-energy areas may over-melt the base material, while low-energy areas may suffer from insufficient fusion, easily causing asymmetrical flow of molten metal to the low-energy area, resulting in external and internal defects such as one-sided undercut, weld bulges or collapses, and weld misalignment.

[0005] 2. Mismatch between scanning amplitude and welding energy: Welding beam current is a key parameter determining the welding energy input and is often dynamically adjusted according to changes in plate thickness and bevel. A scanning waveform with a fixed amplitude means that the oscillation amplitude of the electron beam remains constant regardless of the beam current. At low beam currents, an excessively large amplitude may lead to excessive energy dispersion, resulting in excessively wide weld beads and insufficient penetration; at high beam currents, an excessively small amplitude may lead to excessive energy concentration, exacerbating the risk of undercut or burn-through. The inability to dynamically adjust the scanning amplitude with the beam current limits the width of the process window and the stability of the welding process.

[0006] 3. Mismatch between scanning frequency and welding speed: Variations in welding speed affect the distribution density of heat input on the weld. A fixed scanning frequency may result in "overly dense" scanning at high-speed welding and "overly sparse" scanning at low-speed welding, failing to guarantee the uniformity of the scanning cycle per unit weld length, which may affect the uniformity of the weld structure and surface formation.

[0007] In summary, the existing fixed and static scanning waveform control methods are difficult to adapt to dynamically changing welding paths, beam currents, and speeds, which is a technical bottleneck that restricts the improvement of electron beam welding quality and limits its application in more complex components. Summary of the Invention

[0008] (a) Technical problems to be solved The technical problem to be solved by this invention is that the scanning waveform is fixed during electron beam welding, making it impossible to match the welding trajectory in real time.

[0009] (II) Technical Solution To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for dynamically controlling the scanning waveform of electron beam welding, comprising the following steps: S1. Pre-read the welding CNC program to obtain the welding motion trajectory, and generate a pre-stored trajectory point set based on the welding motion trajectory; S2. During the welding process, the current welding position is acquired in real time; S3. Based on the current welding position and the pre-stored trajectory point set, determine the current direction of welding movement; S4. Based on the current direction of motion, dynamically adjust the direction of the electron beam scanning waveform to match the extension direction of the scanning waveform with the current direction of motion. By pre-reading the trajectory and matching the direction in real time, ensure that the extension direction of the scanning waveform is always consistent with the current welding motion direction (i.e., the instantaneous tangent direction of the weld), thereby ensuring that the electron beam energy is symmetrically distributed along the weld centerline. This effectively eliminates inherent defects such as one-sided undercut, weld offset, and uneven width caused by direction mismatch in welding of complex trajectories such as curves and corners, significantly improving the forming quality and consistency of complex path welding.

[0010] Preferably, in step S3, determining the current direction of welding movement specifically includes the following steps: In the pre-stored set of trajectory points, query the next trajectory point closest to the current welding position; Calculate the current motion direction angle based on the current welding position and the coordinates of the next trajectory point. θ .

[0011] Preferably, in step S4, the dynamic adjustment of the direction of the electron beam scanning waveform specifically includes: The preset original scan waveform data is rotated and transformed based on the current motion direction angle θ to obtain the final waveform data after direction adjustment.

[0012] Preferably, the method further includes the following steps: S5. During the welding process, the current welding beam current value is acquired in real time; S6. Dynamically adjust the amplitude of the electron beam scanning waveform based on the ratio of the current welding beam current value to a reference beam current value. Specifically, the reference beam current value is a preset maximum beam current value. I max Amplitude scaling factor ,in, I now This represents the current welding beam current value. Further, the original scan waveform data... (x', y') After adjusting the direction and amplitude, the final waveform data is obtained. (x″, y″) ,satisfy: in, θ This represents the current direction angle of motion.

[0013] The above technical solution solves the problem that fixed amplitude scanning cannot adapt to variable beam current processes. By dynamically scaling the amplitude proportionally to the real-time beam current value, intelligent matching between the scanning range and the welding input energy is achieved: when the beam current is large, the amplitude is automatically increased to disperse energy and prevent local overheating or burn-through; when the beam current is small, the amplitude is automatically decreased to concentrate energy and prevent incomplete fusion or excessively wide weld beads. This significantly widens the process window and improves the adaptability and stability of the welding process to varying plate thicknesses, arc initiation / outitiation parameters, and other scenarios.

[0014] Preferably, the method further includes the following steps: S7. During the welding process, the current welding speed is obtained in real time; S8. The frequency of the electron beam scanning waveform is dynamically adjusted according to the ratio of the current welding speed to a reference welding speed. Specifically, the frequency of the clock signal controlling the waveform data output is adjusted by the ratio to achieve dynamic adjustment of the scanning waveform frequency.

[0015] The above technical solution solves the problem of uneven scanning cycles per unit length of weld when the welding speed varies with fixed-frequency scanning. By making the waveform output frequency change proportionally with the welding speed, it ensures that the number of scanning thermal cycles applied by the electron beam per unit weld length remains essentially constant regardless of the welding speed. This helps to obtain welds with more uniform microstructure and properties, reduces differences in weld microstructure and properties caused by speed fluctuations, and is particularly beneficial for improving the quality consistency of long welds or variable-speed welding.

[0016] Secondly, the present invention also provides a dynamic control device for electron beam welding scanning waveform, comprising a waveform memory, a main control unit, and a signal processing and output unit; the waveform memory is used to store preset original scanning waveform data; the main control unit is configured to communicate with the upper digital control system of the electron beam welding equipment and is electrically connected to the waveform memory, for pre-reading the digital control program, acquiring real-time parameters of the welding process, and executing the dynamic control method for electron beam welding scanning waveform as described in any one of claims 1-8 to generate control commands; the signal processing and output unit is electrically connected to the main control unit and is used to convert the control commands of the main control unit into amplified analog signals and output them to the electron beam deflection coil.

[0017] Preferably, the signal processing and output unit includes a digital-to-analog converter and a signal amplifier; the digital-to-analog converter is used to convert the processed digital waveform signal into an analog voltage signal; the signal amplifier is used to amplify the analog voltage signal to drive the deflection scanning coil.

[0018] (III) Beneficial Effects The above-described technical solution of the present invention has at least the following advantages: 1. This invention ensures that the electron beam energy is symmetrically distributed along the weld centerline by adjusting the scanning waveform direction in real time to align it with the welding motion direction. This fundamentally avoids asymmetrical flow of molten metal caused by a fixed scanning direction, effectively eliminating defects such as one-sided undercut, weld misalignment, and uneven width commonly found in curved or corner welding, resulting in a uniform and smooth weld appearance and stable internal quality.

[0019] 2. This invention achieves adaptive matching between scanning range and welding energy by dynamically correlating the scanning amplitude with the real-time beam current. In variable beam current welding (such as arc initiation, arc termination, and thickness variation areas), it can automatically optimize the energy distribution state, preventing incomplete fusion at low energy and avoiding overburning or burn-through at high energy, thus widening the process window and improving the robustness of the welding process to parameter fluctuations.

[0020] 3. This invention ensures uniform scanning thermal cycling per unit weld length by dynamically adjusting the scanning frequency to match the welding speed. This is beneficial for obtaining welds with more uniform microstructure and properties, reducing microstructural differences caused by speed variations, and is of great significance for improving the overall performance consistency of components.

[0021] 4. The method provided by this invention enables electron beam scanning to intelligently follow any complex welding path (such as a three-dimensional spatial curve or an S-shaped path), solving the application bottleneck of traditional fixed waveform scanning in this field and providing an advanced welding solution for products with complex weld structures such as aerospace engine blades and nuclear energy components.

[0022] 5. The device provided by this invention can be integrated into the existing CNC system of electron beam welding equipment as an independent functional module. This can be achieved through software algorithm upgrades and hardware board expansions, without the need for major modifications to the main structure of the equipment. The implementation cost is low and the upgrade is convenient. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the implementation process of the electron beam welding scanning waveform dynamic control method provided in the embodiments of the present invention.

[0025] Figure 2 This is a schematic diagram of the X-channel waveform being a sine wave provided in an embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the Y-channel waveform being a sine wave provided in an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the figure-eight waveform synthesized by the XY channels provided in an embodiment of the present invention.

[0028] Figure 5 This is a schematic diagram of the waveform after rotation angle provided in an embodiment of the present invention.

[0029] Figure 6 This is a schematic diagram of the state after dynamic adjustment of the scanning waveform direction provided in an embodiment of the present invention.

[0030] Figure 7 This is a schematic diagram of the dynamic adjustment of the scanning waveform frequency provided in an embodiment of the present invention.

[0031] Figure 8 This is a schematic diagram of the structure of the electron beam welding scanning waveform dynamic control device provided in an embodiment of the present invention.

[0032] The labels for the attached figures are as follows: 100. Upper digital control system; 200. Deflection scanning coil; 1. Main control unit; 2. X waveform memory; 3. Y waveform memory; 4. Digital-to-analog converter; 5. Signal amplifier. Detailed Implementation

[0033] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0034] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be located directly on or indirectly on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component.

[0035] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate that the device or element must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating relative importance or the number of technical features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. The specific implementation of this invention will be described in more detail below with reference to specific embodiments: like Figure 1 As shown, this embodiment of the invention provides a method for dynamically adjusting the scanning waveform of electron beam welding, comprising the following steps: The method includes the following basic steps: S1. Trajectory Pre-reading and Discretization: Before welding begins, the control system pre-reads the welding CNC machining program, parsing out the complete welding motion trajectory (composed of straight lines, arcs, etc.). Subsequently, this welding motion trajectory is discretized and interpolated to generate a high-density, sequentially arranged set of welding trajectory points, which is stored in memory. This step provides a reference path for subsequent real-time direction calculations. More specifically, the motion trajectory of complex welds on a plane typically consists of straight lines and arcs. For straight lines, the starting and ending points of the welding motion trajectory can be obtained from the CNC program, a straight line equation can be established, and discretization can be performed to obtain a set of straight line trajectory points. For arcs, the center, radius, and ending point are read from the CNC program, a circular trajectory equation is established, and discretization can be performed to obtain a set of arc trajectory points. These points are then combined to obtain the welding motion trajectory point set.

[0037] S2. Real-time position acquisition: During the welding process, the current welding position of the welding torch (electron torch) relative to the workpiece is acquired in real time. (x 0, y 0 ) This information can be read directly from the CNC system.

[0038] S3. Real-time motion direction calculation: Based on the current welding position obtained in step S2. (x 0 , y 0 ) A fast search (such as nearest neighbor search) is performed on the welding trajectory point set generated in step S1 to find the next target trajectory point after the current point. (x 1 , y 1 ) Based on the coordinates of the current point and the next target point, establish a straight line equation, calculate the vector direction from the current point to the target point, and quantify it as the current motion direction angle. θ ,Right now .

[0039] S4. Dynamic adjustment of scanning waveform direction: Based on the current motion direction angle calculated in step S3... θ An online geometric rotation transformation is performed on the raw scan waveform data (such as circular dot matrix data of one cycle) pre-stored in the waveform memory. The transformation formula is: in (x, y) These are the original waveform data points. (x ’ , y ’ ) This is the final waveform data after rotational transformation. After this transformation, the overall direction of the scanning waveform on the workpiece plane is consistent with the current welding torch movement direction (i.e., the weld tangent direction), ensuring that the oscillation center line of the electron beam coincides with the weld direction.

[0040] Specifically, the principle of electron beam deflection is to change the current in the deflection coils in both the X and Y directions, thereby generating a change in the magnetic field of the coils, which deflects the electron beam passing through the magnetic field. The signals in the X and Y directions are combined to obtain the final electron beam deflection position. For example, when the waveforms in the X and Y directions are sine waves (such as...), the electron beam deflection position is determined by combining the signals in both directions. Figure 2 The X-channel waveform shown, and as... Figure 3 The Y-channel waveform shown is ultimately synthesized into an "8"-shaped deflection waveform, see... Figure 4 The final waveform data after rotation transformation is as follows: Figure 5 As shown. The final scanning waveform combined with the welding motion trajectory is as follows. Figure 6 As shown.

[0041] S5. Real-time beam current acquisition: During the welding process, the current electron beam current value is acquired in real time. .

[0042] S6. Dynamic adjustment of scanning waveform amplitude: based on real-time beam current value. With a preset reference beam current value (preferably the maximum beam current allowed by the process) ) proportional relationship, calculate amplitude scaling factor The coefficients k The final waveform data obtained in step S4 is applied (x', y') Amplitude scaling: This allows the swing amplitude of the scanning waveform to be adjusted linearly in proportion to the welding energy (beam current). When the energy is high, the swing range is appropriately increased to disperse the energy, and when the energy is low, the swing range is appropriately reduced to concentrate the energy.

[0043] Combining steps S4 and S6, the joint adjustment of direction and amplitude can be achieved through a composite transformation matrix: S7. Real-time speed acquisition: Acquire the current welding speed in real time during the welding process. .

[0044] S8. Dynamic adjustment of scanning waveform frequency: based on real-time welding speed. With a preset reference welding speed The ratio of the clock signal frequency for dynamic adjustment of the control waveform data reading and output is used. f' Satisfying the relation: ,in f The reference clock frequency is used. Dynamic adjustment of the scan waveform frequency is as follows: Figure 7 As shown, by increasing or decreasing the output rate of the waveform data, the spatiotemporal frequency of the electron beam scanning on the workpiece is equivalently changed, matching it with the welding speed and ensuring a constant number of scanning cycles per unit weld length, thereby achieving uniform thermal effect.

[0045] like Figure 8 As shown, this embodiment of the invention also provides a dynamic control device for electron beam welding scanning waveform for implementing the above method.

[0046] The device includes: Waveform memory (specifically including X waveform memory 2 and Y waveform memory 3): electrically connected to the main control unit 1, used for non-volatile storage of various preset original scan waveform digital data (such as triangular wave, sine wave, square wave, sawtooth wave, etc.).

[0047] Main Control Unit 1: This unit serves as the core processor of the device. It is configured to communicate with the upper-level CNC system 100 of the electron beam welding equipment (via a serial port). Its functions include: pre-reading and parsing the CNC program to generate a pre-stored trajectory point set; specifically, acquiring process parameters such as welding position, beam current, and speed from the upper-level CNC system 100 in real time; and executing the orientation angle... θ Scaling factor k The system calculates parameters such as frequency ratio; performs real-time calculations such as waveform data rotation transformation and amplitude scaling; and generates control commands. More specifically, the main control unit 1 (microprocessor) establishes a timed loop task to calculate the current deflection rotation angle. θ and the current scaling factor k First, the current welding position information is read from the upper CNC system 100, and the rotation angle is calculated according to the aforementioned method. θ The rotation angle is stored in the system variable. The current beam size is read from the CNC system, and the scaling factor is calculated according to the formula. k The data is also stored in system variables. Each clock cycle, the main control unit 1 retrieves the original scan waveform data from the waveform memory and then calculates the final waveform data according to the formula.

[0048] The signal processing and output unit includes a digital-to-analog converter 4 and a signal amplifier 5. The digital-to-analog converter 4 is electrically connected to the main control unit 1. The digital-to-analog converter 4 is used to convert the final control command into an analog voltage signal. This analog voltage signal is then amplified by the signal amplifier 5 to form a current signal sufficient to drive the deflection scanning coil 200 of the electron beam welding gun, thereby controlling the electron beam to scan according to the dynamically adjusted waveform.

[0049] This invention can be widely applied to precision welding scenarios in fields such as aerospace engine components, high-temperature resistant components for nuclear reactors, and power batteries for new energy vehicles.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for dynamically controlling the scanning waveform in electron beam welding, characterized in that, Includes the following steps: S1. Pre-read the welding CNC program to obtain the welding motion trajectory, and generate a pre-stored trajectory point set based on the welding motion trajectory; S2. During the welding process, the current welding position is acquired in real time; S3. Based on the current welding position and the pre-stored trajectory point set, determine the current direction of welding movement; S4. Based on the current direction of motion, dynamically adjust the direction of the electron beam scanning waveform so that the extension direction of the scanning waveform matches the current direction of motion.

2. The method for dynamic control of electron beam welding scanning waveform as described in claim 1, characterized in that, In step S3, the current direction of welding movement is determined, which specifically includes the following steps: In the pre-stored set of trajectory points, query the next trajectory point closest to the current welding position; Calculate the current motion direction angle based on the coordinates of the current welding position and the next trajectory point. θ .

3. The method for dynamic control of electron beam welding scanning waveform as described in claim 2, characterized in that, In step S4, the dynamic adjustment of the direction of the electron beam scanning waveform specifically includes: The preset original scan waveform data is rotated and transformed based on the current motion direction angle θ to obtain the final waveform data after direction adjustment.

4. The method for dynamic control of electron beam welding scanning waveform as described in any one of claims 1-3, characterized in that, It also includes the following steps: S5. During the welding process, the current welding beam current value is acquired in real time; S6. Based on the ratio of the current welding beam current value to a reference beam current value, dynamically adjust the amplitude of the electron beam scanning waveform.

5. The method for dynamic control of electron beam welding scanning waveform as described in claim 4, characterized in that, In step S6, the reference beam current value is a preset maximum beam current value. I max Amplitude scaling factor ,in, I now This represents the current welding beam current value.

6. The method for dynamic control of electron beam welding scanning waveform as described in claim 5, characterized in that, Raw scan waveform data (x', y') After adjusting the direction and amplitude, the final waveform data is obtained. (x″, y″) ,satisfy: in, θ This represents the current direction angle of motion.

7. The method for dynamic control of electron beam welding scanning waveform as described in claim 1, characterized in that, It also includes the following steps: S7. During the welding process, the current welding speed is obtained in real time; S8. The frequency of the electron beam scanning waveform is dynamically adjusted according to the ratio of the current welding speed to a reference welding speed.

8. The method for dynamic control of electron beam welding scanning waveform as described in claim 7, characterized in that, Step S8 specifically includes the following steps: adjusting the frequency of the clock signal for the control waveform data output by adjusting the ratio of the current welding speed to a reference welding speed, so as to achieve dynamic adjustment of the scanning waveform frequency.

9. A dynamic control device for electron beam welding scanning waveform, characterized in that, include: Waveform memory, used to store preset raw scan waveform data; The main control unit is configured to communicate with the upper digital control system of the electron beam welding equipment and is electrically connected to the waveform memory. It is used to pre-read the digital control program, acquire real-time parameters of the welding process, and execute the dynamic control method for electron beam welding scanning waveform as described in any one of claims 1-8 to generate control commands. The signal processing and output unit is electrically connected to the main control unit and is used to convert the control commands of the main control unit into amplified analog signals and output them to the electron beam deflection coil.

10. The electron beam welding scanning waveform dynamic control device as described in claim 9, characterized in that, The signal processing and output unit includes: A digital-to-analog converter is used to convert processed digital waveform signals into analog voltage signals; A signal amplifier is used to amplify the analog voltage signal to drive the deflection scanning coil.

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