CN116475577B

CN116475577B - Weld joint control method for welding process of CT tube and titanium window

Info

Publication number: CN116475577B
Application number: CN202310753019.2A
Authority: CN
Inventors: 丁凯; 余以智; 章迎朝; 杨和汶
Original assignee: HANGZHOU KAILONG MEDICAL INSTRUMENTS CO Ltd
Current assignee: HANGZHOU KAILONG MEDICAL INSTRUMENTS CO Ltd
Priority date: 2023-06-26
Filing date: 2023-06-26
Publication date: 2023-09-12
Anticipated expiration: 2043-06-26
Also published as: CN116475577A

Abstract

The invention provides a weld joint control method for a welding process of a CT tube and a titanium window, which comprises the following steps: the welding line monitoring module tracks the moving path of the laser welding module in real time and monitors the groove morphology of the welding line in real time in the welding process; the welding control module compares the moving path of the laser welding module with a preset path, calculates the displacement deviation of the laser welding module, and controls the laser welding module to move in a space coordinate system so as to rectify the laser welding module; the welding control module controls welding parameters of the laser welding module according to the groove morphology of the welding line so as to adapt to different groove morphologies. Aiming at the welding requirement of the CT tube and the titanium window, the real-time adjustment of the welding seam path and welding parameters is realized, the closed loop corrects the welding seam offset caused by non-human factors such as path error, thermal deformation, installation dislocation and the like, and the welding quality and the welding precision are improved.

Description

Weld joint control method for welding process of CT tube and titanium window

Technical Field

The invention belongs to the technical field of welding, and relates to a welding seam control method for a welding process of a CT tube and a titanium window.

Background

The conventional CT tube is generally required to be provided with a titanium window as a radiation window, the CT tube has very high requirements on tightness and cannot leak a little, otherwise, the CT tube is invalid; at present, when a titanium window is installed, the titanium window is basically fixedly connected through welding, the existing CT tube shell is basically made of Monel alloy, the titanium window is made of titanium, when welding is carried out through welding materials in the prior art, the welding materials of the titanium window and the CT tube shell have stronger affinity, and the titanium window has poorer affinity, so that the titanium window is welded on the CT tube shell in an infirm manner due to overlarge gap between the titanium window and the CT tube shell, and the radiation leakage and the falling-off of the titanium window outside the CT tube due to insufficient strength are caused due to infirm welding.

The patent with the application publication number of CN113000963A discloses a welding method for a titanium window of a CT tube, firstly, the titanium window and welding flux are pre-welded, a pressing component is arranged on a CT tube shell, the pre-welded titanium window and welding flux are fixed on the CT tube shell through the pressing component, then, when the titanium window is welded on the CT tube shell, a piece of welding flux is added between the titanium window and the CT tube shell, and when the welding flux is connected with the welding flux on the CT tube shell and the titanium window, so that the phenomenon that the welding of the titanium window is unstable due to the reason of affinity of the welding flux is avoided.

In the technical scheme, the CT tube and the titanium window are fixed through the compression assembly, but the welding seam is offset in the welding process due to the existence of thermal deformation in the welding process, so that the welding performance is affected; in addition, as the welding seam between the CT tube and the titanium window is arc-shaped, the groove morphology of the welding seam is continuously changed in the welding process, and the welding parameters cannot adapt to the change of the groove morphology, so that the welding defect is easy to occur.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention aims to provide a welding seam control method for a welding process of a CT tube and a titanium window, aiming at the welding requirement of the CT tube and the titanium window, the real-time adjustment of a welding seam path and welding parameters is realized, the closed loop corrects the welding seam offset caused by non-human factors such as path error, thermal deformation, installation dislocation and the like, and the welding quality and the welding precision are improved.

To achieve the purpose, the invention adopts the following technical scheme:

the invention provides a weld joint control method for a welding process of a CT tube and a titanium window, which comprises the following steps:

pre-welding the titanium window and the first solder in a vacuum environment;

(II) fixing the pre-welded titanium window on the shell of the CT tube, and filling a second welding flux into the joint of the titanium window and the shell of the CT tube;

(iii) soldering the first solder with the second solder in a vacuum environment;

in the step (III), welding equipment adopted in the welding process comprises a welding seam monitoring module, a laser welding module and a welding control module, wherein the welding seam monitoring module is electrically connected with the welding control module, and the welding control module is used for controlling the laser welding module in a feedback manner;

in step (iii), the welding process comprises:

the welding line monitoring module tracks the moving path of the laser welding module in real time and monitors the groove morphology of the welding line in real time in the welding process;

the welding control module compares the moving path of the laser welding module with a preset path, calculates the displacement deviation of the laser welding module, and controls the laser welding module to move in a space coordinate system so as to rectify the laser welding module;

the welding control module controls welding parameters of the laser welding module according to the groove morphology of the welding line so as to adapt to different groove morphologies.

As a preferred embodiment of the present invention, in the step (iii), the welding process at least includes the following steps:

(1) Carrying out surface treatment on the welding area, and preheating the treated surface to be welded;

(2) Carrying out laser welding on the welding area by adopting a laser welding module, wherein in the welding process, laser beams emitted by the laser welding module periodically swing in the welding area;

(3) A target moving path of the laser welding module is input in the welding control module in advance, and in the welding process, the welding seam monitoring module tracks the moving path of the laser welding module in real time and monitors the groove morphology of the welding seam in real time;

(4) The welding control module collects a real-time moving path of the laser welding module, calculates a path deviation correction amount of the laser welding module according to comparison of the real-time moving path and a target moving path, and adjusts a moving track of the laser welding module according to the path deviation correction amount;

(5) The welding control module collects the groove morphology of the welding line, the groove morphology at the welding line is slightly changed along with the continuous progress of the welding process, and the welding control module adjusts laser welding parameters according to the changed groove morphology.

The welding seam control method provided by the invention aims at the welding requirements of the CT tube and the titanium window, realizes real-time adjustment of a welding seam path and welding parameters, corrects the welding seam offset caused by non-human factors such as path error, thermal deformation, installation dislocation and the like in a closed loop, and improves the welding quality and the welding precision.

As a preferred embodiment of the present invention, in the step (1), the surface treatment process of the welding area includes:

polishing the welding area, and removing an oxide layer and dirt on the surface to be welded;

the polished surface to be welded may be preheated to 100 to 150 ℃, for example, 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, 145 ℃ or 150 ℃, but is not limited to the values listed, and other values not listed in the range are equally applicable.

As a preferred embodiment of the present invention, in the step (2), the periodically oscillating path includes a curve or a spiral;

the curved swing path is as follows: the laser beam moves linearly along the welding line direction on the surface of the welding line at a uniform speed, and meanwhile, the laser beam performs single pendulum periodic motion in a plane vertical to the welding line direction, and the uniform speed linear motion and the single pendulum periodic motion are combined to form sinusoidal oscillation in a welding area;

the spiral swing path is specifically as follows: the laser beam moves linearly on the surface of the welding seam along the welding seam direction at a uniform speed, and simultaneously, the laser beam moves circularly in a plane parallel to the welding area, and the uniform speed linear movement and the circular movement are combined to form spiral propelling swing in the welding area.

In the welding method provided by the invention, the laser beam emitted by the laser welding module periodically swings in the welding molten pool according to different moving tracks, so that a larger gradient temperature change is formed in the molten pool, and the surface tension of the molten pool is influenced, so that the effect of refining welding structure grains is realized. In addition, in the periodic swinging process of the laser beam, the solidified melt can be remelted, and the effect of refining weld joint structure grains can be achieved.

As a preferable technical scheme of the invention, the welding seam monitoring module comprises a path tracking unit and a morphology detection unit which are respectively and electrically connected with the welding control module; in the welding process, the path tracking unit and the morphology detection unit synchronously move along with the laser welding module so as to track the moving path of the laser welding module and the morphology of the weld groove in real time;

the appearance detection unit is positioned at the front end of the laser welding module, and enters a region to be welded before the laser welding module in the welding process, and scans the groove appearance of a welding line before the region to be welded is not welded so as to determine the operation parameters of the region to be welded in the welding process;

The path tracking unit comprises an exciting coil, an induction coil, an exciting power supply, a power amplifying circuit, a shaping filter circuit, an operational amplifying circuit and an analog-to-digital conversion circuit;

the exciting power supply is provided with a first output end and a second output end, and the first output end is electrically connected with the exciting coil through the power amplifying circuit; the second output end is electrically connected with the welding control module; the excitation power supply simultaneously sends excitation current signals to the excitation coil and the welding control module through the first output end and the second output end;

the output end of the induction coil is electrically connected with the shaping filter circuit, the operational amplification circuit and the analog-to-digital conversion circuit in sequence, and the output end of the analog-to-digital conversion circuit is electrically connected with the welding control module;

the induction coil is positioned above the welding line, and the exciting coil is positioned above the induction coil;

in the step (3), the real-time tracking process of the moving path of the laser welding module includes:

the excitation power supply outputs an excitation current signal of a sine waveform, the excitation current signal drives the excitation coil through the power amplification circuit, and the excitation coil generates an induction magnetic field;

The induction coil converts an induction magnetic field generated by the excitation coil into an induction current signal, and the induction current signal is processed by the shaping filter circuit, the operational amplification circuit and the analog-to-digital conversion circuit and then is synchronously input to the welding control module with an excitation current signal output by the excitation power supply;

the welding control module calculates the displacement of the deflection of the welding seam according to the waveform of the induction current signal, thereby obtaining the real-time moving path of the laser welding module.

The welding seam control method provided by the invention realizes real-time tracking of the welding seam generation path, corrects the path deviation of the laser welding module in time, ensures that the laser welding module moves according to the preset welding seam direction, and prevents welding deviation. The tracking principle is as follows:

after excitation current signals are introduced into the excitation coil, the excitation coil generates an alternating magnetic field in the surrounding space, and the surface of the welding seam induces the alternating current field due to the existence of skin effect. Before soldering, since the materials of the first solder and the second solder are the same, the resistivity in the solder joint region is almost the same everywhere, and thus, the electric field lines in the alternating current field are parallel and uniformly distributed to each other. When the welding seam is welded, a welding joint is formed at the welding seam, the resistivity at the edge of the welding seam is obviously larger than that of surrounding areas, the alternating current field is distorted due to the change of the resistivity, the uniform distribution of the electric field lines is destroyed, the electric field lines can be converged and deflected at the edge of the welding seam, the current density at the edge of the welding seam is reduced, the distribution of the electric field lines at the edge of the welding seam is looser, and the density distribution of the alternating magnetic field generated by the exciting coil is correspondingly changed. The induction electromotive force generated by the change of the density distribution of the alternating magnetic field can be obtained by measuring the magnetic flux change of the induction coil, the induction coil converts the induction electromotive force into an induction current signal, and the welding control module compares the excitation current signal with the induction current signal to obtain the path information of the welding seam.

As a preferred technical solution of the present invention, step (2) further includes:

in the welding process, exciting current signals are led into the exciting coil through the exciting power supply, so that an induction magnetic field is generated around the exciting coil, and the induction magnetic field carries out electromagnetic stirring on the solder melt in the molten pool so as to refine a weld joint structure;

the peak current value of the exciting current signal outputted from the exciting power supply is 100-200A, for example, 100A, 110A, 120A, 130A, 140A, 150A, 160A, 170A, 180A, 190A or 200A, but is not limited to the listed values, and other non-listed values within the range of values are equally applicable.

The frequency of the exciting current signal output by the exciting power supply is 20-30Hz, for example, 20Hz, 21Hz, 22Hz, 23Hz, 24Hz, 25Hz, 26Hz, 27Hz, 28Hz, 29Hz or 30Hz, but is not limited to the recited values, and other non-recited values within the range of the values are equally applicable.

The duty ratio of the excitation current signal output by the excitation power supply is 0.2-0.5, for example, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 or 0.5, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In the invention, the induction magnetic field generated by the exciting coil can be used for tracking a welding seam, and can also be used for simultaneously carrying out electromagnetic stirring on the melt in the molten pool, so that the solder melt in the molten pool forms vortex, the interaction between the vortex and the magnetic field generates Lorentz force and magnetic pressure, the strength of the magnetic field is far greater than the dynamic pressure of the solder melt, so that the solder melt generates strong vibration, the welding pool is promoted to be fully stirred, and the stirring vibration has the effects that:

(1) The supercooling degree in the solidification of the melt is increased, and the nucleation rate is improved, so that the crystallization condition of the solder melt in a welding pool is improved, and the welding solidification process and the temperature field distribution are changed;

(2) Forced convection is caused in the melt by magnetic stirring vibration, so that the growth process of dendrites in the solidification process is inhibited, or broken dendrite fragments are formed, and broken dendrite particles are dissociated in the melt at the front of crystallization to become new nucleation centers, so that the equiaxed crystal proportion is increased, coarse dendrites are reduced, the crystallization orientation is improved, and finally, the tissue refinement is realized;

(3) And air holes in the solder melt are discharged through electromagnetic stirring, so that the welding defect rate is reduced, and the toughness of the welding seam is improved.

Because the welding process of the CT tube and the titanium window has extremely strict requirements on the welding tightness, the structure grains at the welding seam are required to be thinned as far as possible, so that the structure grains are uniform, and the phenomenon of stress concentration is prevented from occurring, thereby causing the cracking at the welding seam. Therefore, in order to ensure the welding requirement, the invention is applied to the narrow gap welding process of the CT tube and the titanium window in a mode of combining the laser beam space spiral swing mode and the pulsed magnetic field vortex disturbance, and realizes the refinement of the narrow gap weld joint structure grains of the CT tube and the titanium window on the premise of ensuring the welding quality, so that the impact toughness of a welding joint between the CT tube and the titanium window is greatly improved by about 50 percent compared with a base metal.

As a preferable technical scheme of the invention, the appearance detection unit comprises an industrial camera, a laser transmitter, a collimating lens, a vibrating mirror and a driving motor, wherein the vibrating mirror is close to the transmitting end of the laser transmitter, the collimating lens is arranged between the vibrating mirror and the laser transmitter, and the driving motor drives the vibrating mirror to rotate;

in the step (3), the real-time monitoring process of the groove morphology of the welding line comprises the following steps:

the laser transmitter transmits scanning laser, the scanning laser forms structural light with grating stripes after being reflected by the reflecting surface of the vibrating mirror and projects the structural light to a weld groove of an unwelded part, and the bent grating stripes are formed at the weld groove;

The reflection surface of the vibrating mirror is driven by the driving motor to reciprocally rotate at a preset frequency within a preset angle, so that grating stripes reciprocally move at a weld groove, and different positions of the weld groove are projected;

the industrial camera shoots a grating image formed at a welding groove and transmits the grating image to the welding control module, and the welding control module processes the grating image to obtain the morphological parameters of the welding groove;

the processing process of the grating image comprises the following steps:

the welding control module performs windowing on the original grating image according to the historical information, reduces the pixel size of the original grating image by 90-95%, for example, 90%, 90.5%, 91%, 91.5%, 92%, 92.5%, 93%, 93.5%, 94%, 94.5% or 95%, but is not limited to the recited values, and other non-recited values in the range of values are equally applicable.

Filtering the reduced grating image by using a Gaussian-Laplace operator, and removing the reflected light interference of the grating at the weld groove to obtain a grating image with clear stripes;

calculating the dimension parameters of the weld groove morphology according to the processed grating image, wherein the dimension parameters comprise: the total height of the first solder and the second solder, the height of the gap between the first solder and the second solder, the width of the gap between the first solder and the second solder, and the bevel angle between the first solder and the second solder.

In the present invention, the grating image obtained by the structured light needs to be subjected to noise reduction processing, and noise can be classified into stationary noise and non-stationary noise according to statistical characteristics, the stationary noise being non-time-varying, and the non-stationary noise being time-varying. In the weld control method provided by the invention, electromagnetic wave interference generated by the exciting coil and the induction coil is stable noise, and noise generated by splash, arc light, weldment reflection and the like is non-stable noise. In order to filter stationary noise and non-stationary noise simultaneously, the invention adopts a Gaussian-Laplacian operator for filtering, and the filtering method has maximum response at the center point of the grating stripe, and can separate the grating stripe from interference noise such as electromagnetic wave interference, splash interference, arc light interference, weldment reflection and the like.

In the invention, the width of the grating stripe at the weld groove is 5 pixels, and the grating stripe is positioned at the maximum response value of the Gaussian-Laplacian operator. Therefore, in the raster image, noises such as arc light, spatter, smoke dust, and weldment reflection, which have a pixel width of more than 5 pixels, are suppressed. After being processed by a Gaussian-Laplace operator, the grating has uniform stripe width, and the stripe strength is inhibited in a wider stripe area; in the area where the stripes are narrower, the stripe strength is enhanced. The processed grating image has clear and sharp edges, no noise interference such as electromagnetic waves, arc lights, splashes, smoke dust, weldment reflection and the like, and various dimension parameters of a welding groove can be more accurately calculated according to the grating image, so that the follow-up accurate adjustment of the welding parameters is facilitated.

In addition, as the welding line between the CT tube and the titanium window is a curve, the invention is preferably provided with the industrial cameras on two sides of the welding line respectively, and the two industrial cameras shoot grating images of the welding line surface from different sides, so that the curvature calculation of the curve welding line can be realized, the curve welding line is used for predicting the trend of the welding line, reliable data is provided for the posture adjustment and the path adjustment of the laser welding module, and the accurate control capability of the movement track of the laser welding module is improved.

In step (4), the welding control module calculates a path offset according to the real-time path of the laser welding module and the weld target path acquired by the path tracking unit, and controls the moving path of the laser welding module, and specifically includes the following steps:

inputting a target path parameter consisting of a target x coordinate and a target y coordinate into the welding control module, wherein the target x coordinate is arranged along the welding line direction, and the target y coordinate is arranged along the direction perpendicular to the welding line direction;

the path tracking unit acquires real-time x coordinates and real-time y coordinates of real-time path parameters and inputs the real-time x coordinates and the real-time y coordinates into the welding control module;

The welding control module calculates welding path offset delta x in the x direction according to the target x coordinate and the real-time x coordinate, and calculates welding path offset delta y in the y direction according to the target y coordinate and the real-time y coordinate;

and the welding control module controls the moving path of the laser welding module according to the welding path offset delta x and delta y.

As a preferred embodiment of the present invention, in the step (5), the adjusting process of the laser welding parameter includes:

t < th > at the time of welding _n At moment, acquiring the weld groove morphology parameters at the current moment through the morphology detection unit comprises the following steps: the total height M of the first solder and the second solder _n A gap height N between the first solder and the second solder _n Gap width S between the first solder and the second solder _n The bevel angle alpha between the first solder and the second solder _n ；

T < th > at the time of welding _n+1 At moment, acquiring the weld groove morphology parameters at the current moment through the morphology detection unit comprises the following steps: the total height M of the first solder and the second solder _n+1 A gap height N between the first solder and the second solder _n+1 Gap width S between the first solder and the second solder _n+1 The bevel angle alpha between the first solder and the second solder _n+1 ；

According to t _n Calculating the t-th weld groove morphology parameter at the moment _n Groove area D at time _n ，D _n The calculation formula of (2) is as follows:

formula (1);

according to t _n+1 Calculating the t-th weld groove morphology parameter at the moment _n+1 Groove area D at time _n+1 ，D _n+1 The calculation formula of (2) is as follows:

formula (2);

according to D _n And D _n+1 Calculating corrected welding parameters including welding current and laser power;

the welding current before correction is I _n The corrected welding current is I _n+1 ，I _n+1 The calculation formula of (2) is as follows:

formula (3);

the welding power before correction is P _n The corrected welding current is P _n+1 ，P _n+1 The calculation formula of (2) is as follows:

formula (4);

the laser welding module emits a laser beam to the welding area according to the corrected welding current and welding power.

Because the welding seam control method provided by the invention aims at the welding process of the CT tube and the titanium window, the welding seam between the CT tube and the titanium window is a curved surface, the morphology of a welding seam groove changes along with the advancing time of the welding process, and if the same welding parameters are adopted, the welding seam is penetrated or the welding seam cannot be completely melted, so that the welding performance is affected. Therefore, the welding parameters are adjusted in real time by utilizing the groove morphology of the welding seam detected by the groove morphology unit, the dynamic adjustment of the welding parameters is realized, the welding current and the welding power corresponding to the current groove morphology condition are calculated in real time according to the size parameters such as the solder height, the gap width, the groove angle and the like obtained by the groove morphology unit, the laser welding module is controlled by the welding control module to adjust the welding current and the welding power in time, the problem of weld defect caused by groove morphology change and unmatched heat input can be solved, meanwhile, the cost of labor materials is reduced, the production period is shortened, and the welding efficiency is improved.

As a preferable technical scheme of the invention, the laser welding module comprises two welding devices which are distributed on two sides of the welding seam in a mirror symmetry mode;

the welding device comprises a mobile station and a laser welding gun arranged on the mobile station, wherein the laser welding gun simultaneously emits laser beams with the same parameters to two sides of the welding seam, and an included angle between the laser beams emitted by the laser welding gun and the plane of the welding seam area is 30-40 degrees;

the welding seam monitoring module is arranged on the mobile station and moves synchronously with the laser welding gun;

the mobile station and the laser welding gun are respectively connected with the welding control module, and the welding control module is used for controlling the mobile station to move so as to adjust the moving path of the laser welding gun and adjusting the laser parameters sent by the laser welding gun.

The laser welding gun, the path tracking unit and the morphology detection unit which are configured on the mobile station provided by the invention have a certain arrangement sequence, and the morphology detection unit, the laser welding gun and the path tracking unit are sequentially arranged along the moving direction of the mobile station. In the welding process, along with the movement of the mobile station, the morphology detection unit firstly enters a welding area and scans the groove morphology of an unwelded welding line; the moving table continues to move, the laser welding guns enter the area to be welded, the laser welding guns on two sides of the welding line simultaneously emit laser to the welding line, and the first welding flux and the second welding flux at the welding line are subjected to fusion welding; the mobile station continues to move, the path tracking unit finally enters the welding area, the area to be welded at the moment is welded by laser to form a welding joint, and the path tracking unit positions the welding joint to monitor whether the welding path is deviated or not.

Compared with the prior art, the invention has the beneficial effects that:

(1) The welding seam control method provided by the invention aims at the welding requirements of the CT tube and the titanium window, realizes real-time adjustment of a welding seam path and welding parameters, corrects the welding seam offset caused by non-human factors such as path error, thermal deformation, installation dislocation and the like in a closed loop, and improves the welding quality and the welding precision;

(2) In the welding method provided by the invention, the laser beam emitted by the laser welding module periodically swings in the welding molten pool according to different moving tracks, so that a larger gradient temperature change is formed in the molten pool, and the surface tension of the molten pool is influenced, so that the effect of refining welding structure grains is realized. In addition, in the periodic swinging process of the laser beam, the solidified melt can be remelted, and the effect of refining weld joint structure grains can be achieved;

(3) The induction magnetic field generated by the path tracking unit can be used for tracking welding seams, and can also be used for simultaneously carrying out electromagnetic stirring on the melt in the molten pool, so that the solder melt in the molten pool forms vortex, the vortex and the magnetic field interact to generate Lorentz force and magnetic pressure, the strength of the magnetic field is far greater than the dynamic pressure of the solder melt, so that the solder melt generates strong vibration, the welding molten pool is promoted to be fully stirred, the structure grains at the welding seams are thinned, the structure grains are uniform, and the conditions of stress concentration and cracking at the welding seams are prevented;

(4) According to the invention, the welding parameters are adjusted in real time by utilizing the groove morphology of the welding seam detected by the groove morphology unit, so that the dynamic adjustment of the welding parameters is realized, the welding current and the welding power corresponding to the current groove morphology condition are calculated in real time according to the size parameters such as the solder height, the gap width, the groove angle and the like obtained by the groove morphology unit, and the laser welding module is controlled by the welding control module to adjust the welding current and the welding power in time, so that the problem of weld defects caused by groove morphology change and unmatched heat input can be solved, meanwhile, the cost of labor materials is reduced, the production period is shortened, and the welding efficiency is improved.

Drawings

FIG. 1 is a schematic view of a welding apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a path tracking unit according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a topography detection unit according to an embodiment of the present invention;

fig. 4 is a graph of weld path deviation correction provided in an embodiment of the present invention.

Wherein: 1-a first solder; 2-a second solder; 3-a mobile station; 4-a laser welding module; a 5-path tracking unit; 6-a morphology detection unit; 7-welding seams; 8-an industrial camera; 9-a laser emitter; 10-a collimating lens; 11-vibrating mirror; 12-driving a motor; 13-an excitation power source; 14-a welding control module; 15-exciting coil; 16-an induction coil; 17-shaping filter circuits; an 18-operational amplifier circuit; a 19-analog-to-digital conversion circuit; 20-a power amplifying circuit.

Detailed Description

The technical scheme of the application is described in detail below with reference to specific embodiments and attached drawings. The examples described herein are specific embodiments of the present application for illustrating the concept of the present application; the description is intended to be illustrative and exemplary in nature and should not be construed as limiting the scope of the application in its aspects. In addition to the embodiments described herein, those skilled in the art can adopt other obvious solutions based on the disclosure of the claims and the specification thereof, including those adopting any obvious substitutions and modifications to the embodiments described herein.

The drawings in the present specification are schematic views, which assist in explaining the concept of the present application, and schematically show the shapes of the respective parts and their interrelationships. It should be understood that for the purpose of clearly showing the structure of various parts of embodiments of the present application, the drawings are not drawn to the same scale and like reference numerals are used to designate like parts in the drawings. The technical scheme of the application is further described by the following specific embodiments.

It is to be understood that in the description of the present application, the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the drawings, are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus are not to be construed as limiting the present application. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.

It should be noted that, in the description of the present invention, unless explicitly specified and limited otherwise, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art in a specific case.

In one embodiment, a method for controlling a weld 7 for a welding process of a CT tube and a titanium window is provided, comprising:

pre-soldering the titanium window with the first solder 1 in a vacuum environment;

(II) fixing the pre-welded titanium window on the shell of the CT tube, and filling a second welding flux 2 at the joint of the titanium window and the shell of the CT tube;

(iii) soldering the first solder 1 with the second solder 2 in a vacuum environment;

in the step (iii), as shown in fig. 1, the welding equipment adopted in the welding process comprises a welding seam monitoring module, a laser welding module 4 and a welding control module 14, wherein the welding seam monitoring module is electrically connected with the welding control module 14, and the welding control module 14 feedback controls the laser welding module 4;

In step (iii), the welding process comprises:

the welding line monitoring module tracks the moving path of the laser welding module 4 in real time and monitors the groove morphology of the welding line 7 in real time in the welding process;

the welding control module 14 compares the moving path of the laser welding module 4 with a preset path, calculates the displacement deviation of the laser welding module 4, and controls the laser welding module 4 to move in a space coordinate system so as to rectify the laser welding module 4;

the welding control module 14 controls the welding parameters of the laser welding module 4 according to the groove morphology of the welding line 7 so as to adapt to different groove morphologies.

In some embodiments, in step (iii), the welding process comprises at least the steps of:

(2) The welding area is welded by adopting a laser welding module 4, and in the welding process, the laser beam emitted by the laser welding module 4 periodically swings in the welding area;

(3) A target moving path of the laser welding module 4 is input in the welding control module 14 in advance, and in the welding process, the welding seam monitoring module tracks the moving path of the laser welding module 4 in real time and monitors the groove morphology of the welding seam 7 in real time;

(4) The welding control module 14 collects real-time moving paths of the laser welding module 4, calculates path deviation correction amount of the laser welding module 4 according to comparison between the real-time moving paths and target moving paths, and adjusts moving tracks of the laser welding module 4 according to the path deviation correction amount;

(5) The welding control module 14 collects the groove morphology of the welding line 7, the groove morphology at the welding line 7 is slightly changed along with the continuous progress of the welding process, and the welding control module 14 adjusts the laser welding parameters according to the changed groove morphology.

The welding seam 7 control method provided by the embodiment aims at the welding requirements of the CT tube and the titanium window, realizes real-time adjustment of the path and welding parameters of the welding seam 7, corrects the deviation of the welding seam 7 caused by non-human factors such as path error, thermal deformation, installation dislocation and the like in a closed loop, and improves the welding quality and the welding precision.

In some embodiments, in step (1), the surface treatment process of the welding region includes:

polishing the welding area, and removing an oxide layer and dirt on the surface to be welded; preheating the polished surface to be welded to 100-150 ℃.

In some embodiments, in step (2), the periodically oscillating path comprises a curve or a spiral.

The curved swing path is: the laser beam moves linearly on the surface of the welding line 7 along the direction of the welding line 7 at a constant speed, and simultaneously, the laser beam performs single pendulum periodic motion in a plane perpendicular to the direction of the welding line 7, and the constant speed linear motion and the single pendulum periodic motion are combined to form sinusoidal oscillation in a welding area.

The spiral swing path is specifically: the laser beam moves linearly on the surface of the welding line 7 along the direction of the welding line 7 at a uniform speed, and simultaneously, the laser beam moves circularly in a plane parallel to the welding area, and the uniform speed linear movement and the circular movement are combined to form spiral propelling swing in the welding area.

In the welding method provided by the embodiment, the laser beam emitted by the laser welding module 4 periodically swings in the welding molten pool according to different moving tracks, so that a larger gradient temperature change is formed in the molten pool, and the surface tension of the molten pool is affected, so that the effect of refining welding structure grains is realized. In addition, during the periodic oscillation of the laser beam, the solidified melt can be remelted, and the effect of refining the structural grains of the weld joint 7 can be achieved.

In some embodiments, the weld monitoring module includes a path tracking unit 5 and a profile detection unit 6 electrically connected to the welding control module 14, respectively; in the welding process, the path tracking unit 5 and the profile detection unit 6 synchronously move along with the laser welding module 4 so as to track the moving path of the laser welding module 4 and the profile of the groove of the welding line 7 in real time.

The appearance detection unit 6 is located at the front end of the laser welding module 4, and in the welding process, the appearance detection unit 6 enters the to-be-welded area before the laser welding module 4, and the appearance detection unit 6 scans the groove appearance of the welding seam 7 before the to-be-welded area is not welded so as to determine the operation parameters of the to-be-welded area during welding.

In the embodiment shown in fig. 2, the path tracing unit 5 includes an exciting coil 15, an induction coil 16, an exciting power supply 13, a power amplifying circuit 20, a shaping filter circuit 17, an operational amplifying circuit 18, and an analog-to-digital conversion circuit 19.

The exciting power supply 13 has a first output end and a second output end, and the first output end is electrically connected with the exciting coil 15 through the power amplifying circuit 20; the second output end is electrically connected with the welding control module 14; the excitation power source 13 simultaneously sends excitation current signals to the excitation coil 15 and the welding control module 14 through the first output terminal and the second output terminal.

The output end of the induction coil 16 is electrically connected with the shaping filter circuit 17, the operational amplifier circuit 18 and the analog-to-digital conversion circuit 19 in sequence, and the output end of the analog-to-digital conversion circuit 19 is electrically connected with the welding control module 14.

An induction coil 16 is located above the weld 7 and an excitation coil 15 is located above the induction coil 16.

In step (3), the real-time tracking process of the moving path of the laser welding module 4 includes:

the excitation power supply 13 outputs an excitation current signal with a sine waveform, the excitation current signal drives the excitation coil 15 through the power amplification circuit 20, and the excitation coil 15 generates an induction magnetic field;

the induction coil 16 converts the induction magnetic field generated by the exciting coil 15 into an induction current signal, and the induction current signal is processed by the shaping and filtering circuit 17, the operational amplification circuit 18 and the analog-to-digital conversion circuit 19 and then is input to the welding control module 14 in synchronization with the excitation current signal output by the excitation power supply 13.

The conductivity at the center of the welding line 7 is different from that at the vicinity of the groove of the welding line 7, when the center of the welding line 7 deflects, the normal magnetic field component at the center of the welding line 7 changes, so that the waveform of the induced current signal is influenced, and the welding control module 14 calculates the deflection displacement of the welding line 7 according to the waveform of the induced current signal, so that the real-time moving path of the laser welding module 4 is obtained.

The control method for the welding seam 7 provided by the embodiment realizes real-time tracking of the generation path of the welding seam 7, corrects the path deviation of the laser welding module 4 in time, ensures that the laser welding module 4 moves along the preset direction of the welding seam 7, and prevents the welding deviation. The tracking principle is as follows:

After excitation current signals are introduced into the excitation coil 15, the excitation coil 15 generates an alternating magnetic field in the surrounding space, and the surface of the welding line 7 induces the alternating current field due to the existence of skin effect. Before soldering, since the materials of the first solder 1 and the second solder 2 are the same, the resistivity in the region of the solder joint 7 is almost the same everywhere, and thus, the electric field lines in the alternating current field are parallel to each other and uniformly distributed. When the welding seam 7 is welded, a welding joint is formed at the welding seam 7, the resistivity at the edge of the welding seam 7 is obviously larger than that of surrounding areas, the alternating current field is distorted due to the change of the resistivity, the uniform distribution of the electric field lines is destroyed, the electric field lines can be converged and deflected at the edge of the welding seam 7, the current density at the edge of the welding seam 7 is reduced, the distribution of the electric field lines at the edge of the welding seam 7 is looser, and the density distribution of the alternating magnetic field generated by the exciting coil 15 is correspondingly changed. By measuring the magnetic flux change of the induction coil 16, the induced electromotive force generated by the change of the density distribution of the alternating magnetic field can be obtained, the induction coil 16 converts the induced electromotive force into an induced current signal, and the welding control module 14 compares the excited current signal with the induced current signal, so that the path information of the welding seam 7 can be obtained.

In some embodiments, step (2) further comprises:

in the welding process, excitation current signals are introduced into the excitation coil 15 through the excitation power supply 13, so that an induction magnetic field is generated around the excitation coil 15, and the induction magnetic field carries out electromagnetic stirring on the solder melt in the molten pool so as to refine the structure of the welding seam 7.

The peak value of the exciting current signal output by the exciting power supply 13 is 100-200A, the frequency of the exciting current signal output by the exciting power supply 13 is 20-30Hz, and the duty ratio of the exciting current signal output by the exciting power supply 13 is 0.2-0.5.

In this embodiment, the induced magnetic field generated by the exciting coil 15 may be used to track the weld 7, and also may be used to simultaneously perform electromagnetic stirring on the melt in the molten pool, so that the solder melt in the molten pool forms an eddy current, the eddy current and the magnetic field interact to generate lorentz force and magnetic pressure, the strength of the lorentz force and the magnetic pressure is far greater than the dynamic pressure of the solder melt, so that the solder melt generates strong vibration, and the welding molten pool is caused to be sufficiently stirred, where the stirring vibration has the effects that:

(3) And air holes in the solder melt are discharged through electromagnetic stirring, so that the welding defect rate is reduced, and the toughness of the welding seam 7 is improved.

Because the welding process of the CT tube and the titanium window has extremely strict requirements on the welding tightness, the structure grains at the welding seam 7 are required to be thinned as far as possible, so that the structure grains are uniform, and the phenomenon of stress concentration is prevented from occurring, thereby causing the cracking at the welding seam 7. Therefore, in order to ensure the welding requirement, the method of combining the laser beam space spiral swing mode and the pulsed magnetic field vortex disturbance is applied to the narrow gap welding process of the CT tube and the titanium window, and on the premise of ensuring the welding quality, the structure grain refinement of the narrow gap welding seam 7 of the CT tube and the titanium window is realized, so that the impact toughness of a welding joint between the CT tube and the titanium window is greatly improved, and the impact toughness is improved by about 50% compared with a base metal.

In the embodiment shown in fig. 3, the morphology detection unit 6 includes an industrial camera 8, a laser transmitter 9, a collimating lens 10, a vibrating mirror 11 and a driving motor 12, the vibrating mirror 11 is close to the transmitting end of the laser transmitter 9, the collimating lens 10 is arranged between the vibrating mirror 11 and the laser transmitter 9, and the driving motor 12 drives the vibrating mirror 11 to rotate.

In the step (3), the process of monitoring the groove morphology of the weld 7 in real time comprises the following steps:

the laser emitter 9 emits scanning laser, the scanning laser forms structural light with grating stripes after being reflected by the reflecting surface of the vibrating mirror 11 and projects the structural light to the groove of the welding line 7 at the non-welded position, and the curved grating stripes are formed at the groove of the welding line 7;

the reflecting surface of the vibrating mirror 11 is driven by a driving motor 12 to reciprocally rotate at a preset frequency within a preset angle, so that grating stripes reciprocally move at the groove of the welding seam 7, and different positions of the groove of the welding seam 7 are projected;

the industrial camera 8 shoots a grating image formed at the groove of the welding line 7 and transmits the grating image to the welding control module 14, and the welding control module 14 processes the grating image to obtain the morphological parameters of the groove of the welding line 7.

The processing process of the grating image comprises the following steps:

the welding control module 14 windows the original raster image according to the history information, reducing the pixel size of the original raster image by 90-95%.

And filtering the reduced grating image by adopting a Gaussian-Laplacian operator, and removing the reflected light interference of the grating at the groove of the welding line 7 to obtain the grating image with clear stripes.

Calculating the dimension parameters of the shape of the groove of the welding line 7 according to the processed grating image, wherein the dimension parameters comprise: the total height of the first solder 1 and the second solder 2, the height of the gap between the first solder 1 and the second solder 2, the width of the gap between the first solder 1 and the second solder 2, and the bevel angle between the first solder 1 and the second solder 2.

In this embodiment, the grating image obtained by the structured light needs to be subjected to noise reduction processing, and noise can be classified into stationary noise and non-stationary noise according to statistical characteristics, the stationary noise being non-time-varying, and the non-stationary noise being time-varying. In the control method of the weld joint 7 provided in the present embodiment, electromagnetic wave interference generated by the exciting coil 15 and the induction coil 16 is stationary noise, and noise generated by spatter, arc light, weldment reflection, and the like is non-stationary noise. In order to filter stationary noise and non-stationary noise simultaneously, the present embodiment uses a gaussian-laplace operator for filtering, and the filtering method has the maximum response at the center point of the grating stripe, and can separate the grating stripe from interference noise such as electromagnetic wave interference, splash interference, arc interference, weldment reflection, and the like.

In this embodiment, the width of the grating stripe at the groove of the weld 7 is 5 pixels, which is at the maximum response value of the gaussian-laplace operator. Therefore, in the raster image, noises such as arc light, spatter, smoke dust, and weldment reflection, which have a pixel width of more than 5 pixels, are suppressed. After being processed by a Gaussian-Laplace operator, the grating has uniform stripe width, and the stripe strength is inhibited in a wider stripe area; in the area where the stripes are narrower, the stripe strength is enhanced. The processed grating image has clear and sharp edges, no noise interference such as electromagnetic waves, arc light, splashes, smoke dust, weldment reflection and the like, and various size parameters of the groove of the welding line 7 can be more accurately calculated according to the grating image, so that the follow-up accurate adjustment of the welding parameters is facilitated.

In addition, since the weld 7 between the CT tube and the titanium window in the present embodiment is a curve, in the present embodiment, one industrial camera 8 is preferably disposed on each of two sides of the weld 7, and the two industrial cameras 8 shoot the grating images of the surface of the weld 7 from different sides, so that curvature calculation of the curve weld 7 can be implemented, which is used for predicting the trend of the weld 7, reliable data is provided for posture adjustment and path adjustment of the laser welding module 4, and the precise control capability of the movement track of the laser welding module 4 is improved.

In some embodiments, in step (4), the welding control module 14 calculates the path offset according to the real-time path of the laser welding module 4 and the target path of the weld 7 acquired by the path tracking unit 5, and controls the moving path of the laser welding module 4, and specifically includes the following steps:

inputting a target path parameter consisting of a target x coordinate and a target y coordinate into the welding control module 14, wherein the target x coordinate is arranged along the direction of the welding line 7, and the target y coordinate is arranged along the direction perpendicular to the direction of the welding line 7;

the path tracking unit 5 acquires a real-time x coordinate and a real-time y coordinate of the real-time path parameter and inputs the real-time x coordinate and the real-time y coordinate into the welding control module 14;

the welding control module 14 calculates a welding path offset deltax in the x-direction from the target x-coordinate and the real-time x-coordinate, and calculates a welding path offset deltay in the y-direction from the target y-coordinate and the real-time y-coordinate;

the welding control module 14 controls the movement path of the laser welding module 4 according to the welding path offsets deltax and deltay.

In some embodiments, in step (5), the adjusting of the laser welding parameters includes:

t < th > at the time of welding _n At moment, the morphology parameters of the groove 7 of the welding line at the current moment are obtained through the morphology detection unit 6, and the method comprises the following steps: total height M of first solder 1 and second solder 2 _n Gap height N between first solder 1 and second solder 2 _n Gap width S between first solder 1 and second solder 2 _n The bevel angle alpha between the first solder 1 and the second solder 2 _n ；

T < th > at the time of welding _n+1 At moment, the morphology parameters of the groove 7 of the welding line at the current moment are obtained through the morphology detection unit 6, and the method comprises the following steps: total height M of first solder 1 and second solder 2 _n+1 Gap height N between first solder 1 and second solder 2 _n+1 Gap width S between first solder 1 and second solder 2 _n+1 The bevel angle alpha between the first solder 1 and the second solder 2 _n+1 ；

According to t _n Calculating the t-th weld joint 7 groove morphology parameter at the moment _n Groove area D at time _n ，D _n The calculation formula of (2) is as follows:

formula (1);

formula (2);

formula (3);

formula (4);

The laser welding module 4 emits a laser beam to the welding region according to the corrected welding current and welding power.

Because the control method of the welding seam 7 provided by the embodiment aims at the welding process of the CT tube and the titanium window, the welding seam between the CT tube and the titanium window is a curved surface, the morphology of the groove of the welding seam 7 changes along with the advancing time of the welding process, and if the same welding parameters are adopted, the welding seam is penetrated or the welding seam cannot be completely melted, so that the welding performance is affected. Therefore, the embodiment utilizes the groove morphology of the welding seam 7 detected by the groove morphology unit to adjust the welding parameters in real time, realizes the dynamic adjustment of the welding parameters, calculates the corresponding welding current and welding power under the current groove morphology condition in real time according to the size parameters such as the solder height, the gap width, the groove angle and the like acquired by the groove morphology unit, controls the laser welding module 4 to adjust the welding current and the welding power in time through the welding control module 14, can solve the problem of weld defect caused by groove morphology change and unmatched heat input, simultaneously reduces the cost of labor materials, shortens the production period and improves the welding efficiency.

In the embodiment shown in fig. 1, the laser welding module 4 comprises two welding devices which are distributed mirror symmetrically on both sides of the weld 7; the welding device comprises a movable table 3 and a laser welding gun arranged on the movable table 3, wherein the laser welding gun simultaneously emits laser beams with the same parameters to two sides of the welding line 7, and an included angle between the laser beams emitted by the laser welding gun and the plane where the welding line 7 is located is 30-40 degrees.

The weld monitoring module is arranged on the mobile station 3 and moves synchronously with the laser welding gun. The mobile station 3 and the laser welding gun are respectively connected with a welding control module 14, and the welding control module 14 is used for controlling the mobile station 3 to move so as to adjust the moving path of the laser welding gun and adjusting the laser parameters sent by the laser welding gun.

The laser welding gun, the path tracking unit 5, and the profile detection unit 6 disposed on the mobile station 3 provided in this embodiment have a certain arrangement order, and the profile detection unit 6, the laser welding gun, and the path tracking unit 5 are sequentially disposed along the moving direction of the mobile station 3. In the welding process, along with the movement of the mobile station 3, the morphology detection unit 6 firstly enters a welding area to scan the groove morphology of the unwelded weld 7; the moving table 3 continues to move, the laser welding guns enter the area to be welded, the laser welding guns on two sides of the welding seam 7 simultaneously emit laser to the welding seam 7, and the first welding flux 1 and the second welding flux 2 at the welding seam 7 are subjected to fusion welding; the moving table 3 continues to move, and the path tracking unit 5 finally enters the welding area, at which time the area to be welded has been laser welded to form a welded joint, and the path tracking unit 5 positions the welded joint to monitor whether the welding path is deviated.

Examples

The embodiment provides a welding method of a CT tube and a titanium window, and the disclosed welding method of the CT tube and the titanium window realizes the control of a welding seam between the CT tube and the titanium window on the basis of the welding method of the CT tube and the titanium window by referring to the patent with the publication number of CN 113000963A; the method specifically comprises the following steps:

(1) Polishing the welding area, removing the oxide layer and dirt on the surface to be welded, and preheating the polished surface to be welded to 150 ℃.

(2) The welding area is welded by adopting a laser welding module 4, and in the welding process, the laser beam emitted by the laser welding module 4 swings in a curve type period in the welding area;

(4) In the welding process, excitation current signals are introduced into the excitation coil 15 through the excitation power supply 13, so that an induction magnetic field is generated around the excitation coil 15, and the induction magnetic field carries out electromagnetic stirring on the solder melt in the molten pool so as to refine the structure of the welding seam 7;

the current peak value of the excitation current signal output by the excitation power supply 13 is 150A, the frequency is 25Hz, and the duty ratio is 0.3;

(5) The welding control module 14 collects real-time moving paths of the laser welding module 4, calculates path deviation correction amount of the laser welding module 4 according to comparison between the real-time moving paths and target moving paths, and adjusts moving tracks of the laser welding module 4 according to the path deviation correction amount;

(6) The welding control module 14 collects the groove morphology of the welding line 7, the groove morphology at the welding line 7 is slightly changed along with the continuous progress of the welding process, and the welding control module 14 adjusts the laser welding parameters according to the changed groove morphology.

In the welding process, the path deviation of the welding seam 7 is recorded, and a graph shown in fig. 4 is obtained after summarizing, and as can be seen from fig. 4, the deviation correcting effect of the welding seam 7 provided by the embodiment is good, and under the condition that the deviation is 6mm, the welding is pushed to within 1mm of the length of the welding seam 7, so that the deviation correcting of the laser welding gun can be completed; the welding is advanced to the position 6mm of the length of the welding line 7 under the condition that the deviation is 1mm, and the deviation correction can be completed; when the welding is advanced to 50mm of the length of the welding line 7, the deviation can be reduced to below 0.1mm and almost coincides with the target path of the welding line 7, and the industrial requirements of tracking and correcting the welding line 7 can be completely met.

It should be noted that, the welding control module 14 provided in this embodiment may include a processor, a memory, and a computer program stored in the memory and executable on the processor. The welding control module 14 refers to a terminal having data processing capabilities, including but not limited to a computer, workstation, server, and even some Smart phones, palmtop computers, tablet computers, personal Digital Assistants (PDAs), smart televisions (Smart TVs), etc. that are excellent in performance. The welding control module 14 typically has an operating system installed thereon, including but not limited to: windows operating system, LINUX operating system, android operating system, symbian operating system, windowsmbian operating system, and iOS operating system, etc. Specific examples of the welding control module 14 are set forth above in detail, and those skilled in the art will appreciate that the welding control module 14 is not limited to the examples set forth above.

The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.

Claims

1. A weld control method for a CT tube and titanium window welding process, the weld control method comprising:

pre-welding the titanium window and the first solder in a vacuum environment;

the welding seam monitoring module comprises a path tracking unit and a morphology detection unit which are respectively and electrically connected with the welding control module; in the welding process, the path tracking unit and the morphology detection unit synchronously move along with the laser welding module so as to track the moving path of the laser welding module and the morphology of the weld groove in real time;

The path tracking unit comprises an exciting coil, an induction coil, an exciting power supply, a power amplifying circuit, a shaping filter circuit, an operational amplifying circuit and an analog-to-digital conversion circuit; the exciting power supply is provided with a first output end and a second output end, and the first output end is electrically connected with the exciting coil through the power amplifying circuit; the second output end is electrically connected with the welding control module; the excitation power supply simultaneously sends excitation current signals to the excitation coil and the welding control module through the first output end and the second output end; the output end of the induction coil is electrically connected with the shaping filter circuit, the operational amplification circuit and the analog-to-digital conversion circuit in sequence, and the output end of the analog-to-digital conversion circuit is electrically connected with the welding control module; the induction coil is positioned above the welding line, and the exciting coil is positioned above the induction coil;

the appearance detection unit is positioned at the front end of the laser welding module, and enters a region to be welded before the laser welding module in the welding process, and scans the groove appearance of a welding line before the region to be welded is not welded so as to determine the operation parameters of the region to be welded in the welding process; the appearance detection unit comprises an industrial camera, a laser transmitter, a collimating lens, a vibrating mirror and a driving motor, wherein the vibrating mirror is close to the transmitting end of the laser transmitter, the collimating lens is arranged between the vibrating mirror and the laser transmitter, and the driving motor drives the vibrating mirror to rotate;

In step (iii), the welding process comprises:

the welding control module controls welding parameters of the laser welding module according to the groove morphology of the welding line so as to adapt to different groove morphologies;

in the step (iii), the welding process at least includes the following steps:

(5) The welding control module collects the groove morphology of the welding line, the groove morphology at the welding line is slightly changed along with the continuous progress of the welding process, and the welding control module adjusts the laser welding parameters according to the changed groove morphology;

the excitation power supply outputs an excitation current signal with a sine waveform, the excitation current signal drives the excitation coil through the power amplification circuit, and the excitation coil generates an induction magnetic field;

the welding control module calculates the displacement of the deflection of the welding seam according to the waveform of the induction current signal, thereby acquiring the real-time moving path of the laser welding module;

and the industrial camera shoots a grating image formed at the weld groove and transmits the grating image to the welding control module, and the welding control module processes the grating image to obtain the morphological parameters of the weld groove.

2. The method for controlling a weld joint in a process of welding a CT tube to a titanium window according to claim 1, wherein in step (1), the surface treatment process of the welding region comprises:

preheating the polished surface to be welded to 100-150 ℃.

3. The weld control method for a CT tube to titanium window welding process of claim 1, wherein in step (2), the periodically oscillating path comprises a curved or spiral shape;

4. The weld control method for a CT tube to titanium window welding process of claim 1, wherein step (2) further comprises:

the current peak value of the exciting current signal output by the exciting power supply is 100-200A;

the frequency of the exciting current signal output by the exciting power supply is 20-30Hz;

The duty ratio of the exciting current signal output by the exciting power supply is 0.2-0.5.

5. The weld control method for a CT tube to titanium window welding process of claim 1, wherein the processing of the raster image comprises:

the welding control module opens a small window on the original grating image according to the historical information, and reduces the pixel size of the original grating image by 90-95%;

6. The welding seam control method for a welding process of a CT tube and a titanium window according to claim 1, wherein in step (4), the welding control module calculates a path offset according to the real-time path of the laser welding module and a target path of the welding seam acquired by the path tracking unit, and controls a moving path of the laser welding module, and specifically comprises the steps of:

7. The method for controlling a weld joint in a process of welding a CT tube to a titanium window according to claim 1, wherein in step (5), the process of adjusting the laser welding parameters comprises:

t < th > at the time of welding _n At moment, acquiring the weld groove morphology parameters at the current moment through the morphology detection unit comprises the following steps: the total height M of the first solder and the second solder _n A gap height N between the first solder and the second solder _n A seam between the first solder and the second solderGap width S _n The bevel angle alpha between the first solder and the second solder _n ；

formula (1);

formula (2);

formula (3);

formula (4);

8. The weld control method for a CT tube and titanium window welding process of claim 1, wherein said laser welding module comprises two welding devices, said two welding devices being mirror symmetrically distributed on both sides of said weld;