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CN-121997567-A - Prediction method for laser swing welding track energy distribution

CN121997567ACN 121997567 ACN121997567 ACN 121997567ACN-121997567-A

Abstract

The invention discloses a prediction method of laser swing welding track energy distribution, and belongs to the technical field of laser welding processes. The method comprises the following steps of defining welding process parameters, establishing a mathematical model of an instantaneous movement track of a laser spot, establishing an energy source model based on Gaussian distribution, dividing the surface of a workpiece into grids through space-time discretization, calculating the position of the spot and energy contribution of the spot to surrounding grids in each time step, carrying out iterative accumulation to obtain accumulated energy distribution, and finally outputting a visual energy distribution map and optimizing welding parameters based on the map. The invention can rapidly and accurately predict the energy distribution forms under different swing parameters, realize the digital mapping of the process parameters and the energy distribution, provide scientific basis for the process development and optimization of laser swing welding, and remarkably reduce the test cost and period.

Inventors

  • YUAN LIANGWEN
  • SONG GANG
  • LIU WANCUN
  • FENG DONGXU
  • MENG XIANGDONG
  • LI ZHIJIE
  • Duan Lilei
  • ZHANG YIFEI
  • LIU LIMING

Assignees

  • 大连理工大学
  • 一重集团大连核电石化有限公司

Dates

Publication Date
20260508
Application Date
20251230

Claims (8)

  1. 1. The method for predicting the energy distribution of the laser swing welding track is characterized by comprising the following steps of: Step 1, defining welding process parameters, wherein the welding process parameters comprise laser total power P, beam waist radius r, welding speed V, laser swing track type SM, swing amplitude A and swing frequency f; step 2, establishing mathematical modeling of an instantaneous motion trail of the laser light spot, and constructing a kinematic equation (x (t), y (t)) of the laser light spot center in a two-dimensional workpiece coordinate system along with time t according to the welding motion parameters and the laser welding swing parameters in the step 1, wherein the kinematic equation is vector synthesis of welding linear motion and swing trail motion; Step 3, establishing an instantaneous energy source model, and calculating the instantaneous power density of any point around the light spot at any time t based on the central coordinate of the light spot on the assumption that the energy of the laser beam is in two-dimensional Gaussian distribution inside the light spot; Step 4, performing accumulated energy distribution calculation based on space and space-time discretization, defining a calculation area on the surface of the workpiece, dividing the calculation area into a two-dimensional grid matrix G, and dividing the total welding time into tiny time steps ; Step 5, performing iterative computation and energy accumulation, initializing time t=0, and performing each time step Sequentially calculating the instantaneous position and the energy increment of the light spot, and updating the accumulated energy of the grid unit until the total welding time T is reached; Step 6, generating and outputting an energy distribution map, and carrying out visualization processing on the two-dimensional grid matrix G to obtain a two-dimensional or three-dimensional energy density distribution map; And 7, optimizing welding parameters based on the energy distribution diagram, judging a risk area according to the uniformity of the energy distribution diagram, and returning to the step 1 for recalculation after adjusting the process parameters until the energy distribution diagram meets the requirements.
  2. 2. The prediction method according to claim 1, wherein the laser swing track type SM in step 1 includes a clockwise circular swing (CW), a counterclockwise circular swing (CCW), a Linear swing (Linear), an 8-shaped swing (weight), an Infinity-shaped swing (Infinity), and a regular laser welding mode (SLW).
  3. 3. The prediction method according to claim 1, wherein the X-direction grid number of the two-dimensional grid matrix G in step 4 Number of y-direction grids =550 The resolution of the grid cell is adjusted according to the prediction accuracy and the computation time requirement =550.
  4. 4. The prediction method according to claim 1, wherein in step 4 S to ensure that the movement distance of the spot is much smaller than the spot radius r in one time step.
  5. 5. The prediction method according to claim 1, wherein the instantaneous power density q (x, y, t) in step 3 is expressed as: 。
  6. 6. The method according to claim 1, wherein the parameter adjustment rules in step 7 include increasing the laser wobble amplitude A or decreasing the welding speed V when the edge energy is insufficient, decreasing the laser power P, increasing the wobble frequency f or changing the laser wobble pattern when the center energy is too high.
  7. 7. A prediction method according to claim 1, wherein the visualization process in step 6 comprises generating a pseudo-color two-dimensional map or three-dimensional curved map, characterizing different energy density values by different colors or heights.
  8. 8. The prediction method according to claim 1, wherein the kinematic equation in step 2 is applicable to a wobble track described by any parameterized equation, and is not limited to CW, CCW, linear, eight, infinity and SLW modes.

Description

Prediction method for laser swing welding track energy distribution Technical Field The invention relates to the technical field of laser welding processes, in particular to a prediction method of laser swing welding track energy distribution. Background Laser welding technology is widely used in modern manufacturing because of its high energy density, high precision and high speed. However, the energy of the conventional linear laser welding is in gaussian distribution, and the energy is too concentrated in the center of the welding seam, so that various welding defects such as collapse of the center of the welding seam, serious splashing, air hole generation, poor tolerance to gaps and the like are easily caused. In order to solve the above problems, laser swing welding technology is applied. In laser swing welding, due to the complexity of the swing track, the actual distribution of laser energy on the surface of a workpiece is difficult to visually obtain, and under an unreasonable track, the laser energy distribution can cause welding defects, and different swing parameter combinations, including different swing tracks, swing frequencies and swing amplitudes, can generate distinct weld center energy distribution modes. The uniformity of the energy distribution, the peak position and the size directly influence the flow behavior of the molten pool, the solidification process and the final weld forming quality and mechanical properties. The prior art lacks a fast, accurate, low-cost and effective prediction means, so that the process development can only depend on a trial-and-error method, and the period is long and the cost is high. The prior art generally adopts Gaussian heat source or double-ellipsoid heat source to simulate the temperature field or stress field of the linear welding process. For the prior art, firstly, the swing track is simplified into a static and enlarged light spot, and the residence time difference and the energy superposition effect of the light spot at different positions in space in the high-speed swing process of the laser are completely ignored. Second, the simulation is for theoretical analysis rather than direct guidance of process parameter optimization, apart from the actual control process. It does not establish a complete technical closed loop from "trajectory parameter equations" to "energy distribution visualization" to "process parameter optimization decisions". Thirdly, the calculation is complex and low in efficiency, and the general finite element software is generally adopted to perform multi-physical field coupling calculation, so that the calculation is accurate but takes very long time, and the requirement of a rapid development test process on a production site cannot be met. The prior art scheme either compromises accuracy due to oversimplification of the model or efficiency due to oversimplification of calculation, and fails to provide a laser swing welding energy distribution prediction method which has the advantages of accuracy, calculation efficiency and universality. Disclosure of Invention According to the technical problem, the method for predicting the laser swing welding track energy distribution abandons complex finite element simulation and excessively simplified analysis integration, adopts an efficient numerical calculation strategy, and can accurately predict an actual track motion diagram and a two-dimensional energy density distribution diagram under any given technological parameter in second-level time. The method can rapidly, accurately and low-cost predict the accumulated energy distribution form of the workpiece surface under any given laser parameter and swing parameter, convert abstract process parameters into visual energy distribution images, provide scientific basis for process development, parameter optimization and welding quality pre-control, and solve the problems of blindness and inefficiency in the current laser swing welding process development. The invention adopts the following technical means: A prediction method of laser swing welding track energy distribution comprises the following steps: Step 1, defining welding process parameters, wherein the welding process parameters comprise laser total power P, beam waist radius r, welding speed V, laser swing track type SM, swing amplitude A and swing frequency f; step 2, establishing mathematical modeling of an instantaneous motion trail of the laser light spot, and constructing a kinematic equation (x (t), y (t)) of the laser light spot center in a two-dimensional workpiece coordinate system along with time t according to the welding motion parameters and the laser welding swing parameters in the step 1, wherein the kinematic equation is vector synthesis of welding linear motion and swing trail motion; Step 3, establishing an instantaneous energy source model, and calculating the instantaneous power density of any point around the light spot at any time t based on the centra