CN-122007570-A - Automatic welding method and device for cabinet sheet metal

CN122007570ACN 122007570 ACN122007570 ACN 122007570ACN-122007570-A

Abstract

The invention relates to the technical field of industrial automatic welding, and discloses an automatic welding method and device for cabinet metal plates. The invention aims to solve the problems that the existing welding equipment lacks a seam self-adaptive adjustment mechanism, and is easy to cause sheet burning through, wrong edges to collapse and heat accumulation to induce deformation when continuously welding. The method comprises the steps of extracting gap width and offset drop in a feed-forward planning vision acquisition area, cooperatively adjusting wire feeding and moving speed in response to gap widening, maintaining constant heat input per unit length, controlling a welding gun to transversely deviate and execute asymmetric swing in response to offset exceeding tolerance, guiding a heat source to concentrate towards a bearing surface at a lower side, continuously accumulating step-length heat input quantity, cooperatively adjusting voltage and accelerating and activating a follow-up cooling device to directionally cool a heat affected zone when approaching a deformation critical point.

Inventors

PAN YINGPENG
Liu Atao
DUAN KAIYUAN
ZHANG SHUGUANG
HUANG ZHEN
SU DONGMING

Assignees

许昌东太智能科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260407

Claims (10)

1. An automatic welding method for a cabinet sheet metal is characterized by comprising the following steps: S1, a main control computer plans a data acquisition frame of laser scanning in advance according to the travelling speed and the travelling direction of a multi-axis linear moving mechanism, acquires point cloud data in the data acquisition frame through a single-line laser contour sensor arranged in front of an arc welding gun, and calculates the real gap width of a machine cabinet sheet metal seam and the height difference between two sheet metals; S2, the main control computer synchronously sends control instructions to the digitally controlled welding machine and the multi-axis linear movement mechanism according to the variation of the real gap width, and the walking speed of the multi-axis linear movement mechanism is increased in the same proportion while the wire feeding speed of the welding machine is increased; S3, the main control computer controls the arc welding gun to shift to the side of the sheet metal with the lower position according to the height drop, and controls the arc welding gun to increase the residence time on the side of the sheet metal with the lower position when swinging left and right; And S4, accumulating the total heat output to the metal plate in the whole welding process in real time by the main control computer, sending a voltage reducing instruction to the digitally controlled welding machine when the total heat reaches a preset deformation critical point, simultaneously improving the running speed of the multi-axis linear movement mechanism, and starting a follow-up cooling nozzle positioned behind the arc welding gun to perform targeted cooling.
2. The automatic welding method for the cabinet sheet metal according to claim 1, wherein the specific process of the dynamic acquisition area of the feedforward planning vision sensor in S1 is as follows: The main control computer obtains the current motion parameters of the mobile executing mechanism and the sampling period of the visual sensor, predicts the physical position interval of the area to be welded at the next moment based on the current motion parameters and the sampling period, and defines the dynamic acquisition area by taking the physical position interval as a reference, so as to control the visual sensor to only extract and process the contour data in the dynamic acquisition area, and shield the ambient light and splash interference outside the area.
3. The automatic welding method for the metal plates of the cabinet according to claim 2, wherein the specific process of calculating the actual gap width and the misalignment of the metal plate seam in S1 is as follows: the main control computer extracts the space height difference between adjacent data points in the dynamic acquisition area, eliminates abnormal interference points presenting abrupt change characteristics by setting a height difference change threshold, then fits the rest profile point cloud data to obtain flat line segments representing the surfaces of two metal plates, extracts discontinuous endpoints of the flat line segments as actual physical edges, further obtains the actual gap width by calculating the horizontal distance between the two actual physical edges, and obtains the offset drop by calculating the vertical distance between the two flat line segments.
4. The automatic welding method for the cabinet sheet metal according to claim 1, wherein the specific process of increasing the wire feeding rate of the welding machine in S2 is as follows: In response to the fact that the actual gap width is in an increasing trend, the main control computer calculates additional metal cladding amount required for filling the current increment gap based on a volume conservation principle and combined with the widened gap size and the preset welding wire specification, and issues a corresponding accelerating instruction to a wire feeding executing mechanism of the welding machine, and outputs welding wires matched with the additional metal cladding amount in unit time.
5. The automatic welding method for the cabinet sheet metal according to claim 4, wherein the specific process of cooperatively lifting the traveling speed of the moving actuator in S2 is as follows: The main control computer calculates the target moving speed required for maintaining the constant heat input quantity of the sheet metal in unit length according to the additional electric arc heat input quantity caused by the lifting of the wire feeding speed and the allowable thermal deformation threshold value of the sheet metal material, synchronously drives the moving executing mechanism to accelerate to the target moving speed, and counteracts the additional electric arc heat input quantity by shortening the acting time of the heat source on the unit path.
6. The automatic welding method for the cabinet sheet metal according to claim 1, wherein the specific process of controlling the lateral offset of the energy center position of the welding gun at the sheet metal side with the lower position in S3 is as follows: and responding to the deviation of the edge drop exceeds a set tolerance range, the main control computer calculates a transverse offset distance for avoiding the suspended edge at a high position, and drives the moving executing mechanism to drive the welding gun to transversely move the transverse offset distance, so that the energy center of the welding gun deviates from the original joint center, and the energy center of the welding gun is transferred and aligned with the bearing surface of the metal plate with the lower position.
7. The automatic welding method for cabinet sheet metal according to claim 6, wherein the specific process of assigning a larger residence time ratio to the sheet metal side with the lower position in S3 is as follows: Under the condition that the welding gun is driven to execute transverse swing welding, the main control computer performs asymmetric time distribution on the swing period, so that the residence time ratio of the welding gun on the surface of the sheet metal with lower position is larger than the skimming time ratio of the edge of the sheet metal with higher position, the heat source and the molten pool are guided to be preferentially attached to the bearing surface on the lower side, and the adhesion fusion of the edge at the higher position is realized by the heat attached by the skimming action.
8. The automatic welding method for the metal plate of the cabinet according to claim 1, wherein the specific process of the accumulated heat input amount in the welding process of the continuous integral operation in S4 is as follows: the main control computer synchronously collects real-time output current and real-time output voltage of the welding machine and real-time walking speed of the mobile executing mechanism according to discrete time steps, and obtains corresponding step input line energy in the time steps by carrying out product integral operation on the real-time output current, the real-time output voltage and the real-time walking speed, and accumulates all the step input line energy from a welding starting point to a current position to obtain accumulated heat input quantity reflecting the accumulated heated state of the current sheet metal.
9. The automatic welding method for the cabinet sheet metal according to claim 8, wherein the specific process of adjusting down the output energy parameter of the welding machine and further improving the traveling speed of the moving executing mechanism and synchronously activating the follow-up cooling device in S4 is as follows: Under the condition that the welding gun moves to a preset welding seam rear section and the accumulated heat input quantity is monitored to approach to the deformation critical point, the main control computer downwards adjusts the output voltage of the welding machine as a reduction means of the output energy parameter according to a preset gradient under the condition of maintaining the existing wire feeding filling quantity, simultaneously sends an acceleration instruction to the mobile executing mechanism again to drive away from a high-temperature influence area as soon as possible, synchronously activates the follow-up cooling device which moves along with the welding gun, and directionally sprays cooling medium to the residual heat influence area where welding is completed.
10. An automatic welding device for sheet metal of cabinets, characterized in that it is adapted to perform the method according to any one of claims 1 to 9, comprising in particular: The mobile unit (100), the mobile unit (100) comprises a base (101), transverse guide rails (102) are arranged on two sides of the base (101) in parallel, a longitudinal cross beam (103) is slidably mounted on the transverse guide rails (102), a Z-axis sliding block (104) is slidably mounted on the longitudinal cross beam (103), a bearing cross beam (105) is slidably mounted on the Z-axis sliding block (104), and a clamping device (106) is arranged on the base (101); The welding unit (200), the welding unit (200) comprises a connecting seat (201) arranged on the bearing beam (105), a wire feeding motor (202) arranged on the connecting seat (201), a wire feeding mechanism (203) connected to the bottom end of the wire feeding motor (202), a wire guide tube (204) connected to the output end of the wire feeding mechanism (203), and an arc welding gun (205) arranged on one side of the wire guide tube (204); The auxiliary control unit (300), auxiliary control unit (300) include guide wire pipe (204) with be provided with fixed bolster (301) on arc welder (205), hang support (302) are being connected to fixed bolster (301) one end, be provided with laser profile sensor (303) on hanging support (302), the fixed bolster (301) other end is provided with cooling nozzle (304).

Description

Automatic welding method and device for cabinet sheet metal Technical Field The invention relates to the technical field of industrial automatic welding, in particular to an automatic welding method and device for cabinet metal plates. Background The invention relates to the technical field of industrial automatic welding, in particular to an automatic welding method and device for cabinet metal plates. Along with the continuous promotion of intelligent manufacturing, industrial robots and automatic welding special machines are widely applied to the assembly and manufacture of sheet metal structures such as machine shells, electric control cabinets and the like. In general, cabinet products are mostly formed by splicing thin-wall materials such as thinner cold-rolled steel plates, and have extremely high process requirements on the flatness of the appearance, the continuity of welding seams and the overall structural rigidity. Existing automated welding equipment mostly relies on a fixed trajectory taught manually in advance and preset constant welding parameters for pipelining, or is equipped with only a basic visual tracking system to correct the travel route of the welding gun. However, in the actual batch processing process of the cabinet sheet metal, due to unavoidable processing tolerances in the previous bending, shearing and assembling procedures, the long-distance seam often has physical defects of gap width fluctuation and local high-low misalignment. In addition, because the metal has good heat conductivity, the heat source input is extremely easy to generate residual stress accumulation at the rear section in the welding seam under the condition of continuous welding for a long time and a long distance, thereby inducing irreversible wavy thermal deformation. The existing means are difficult to control the forming quality of complex gaps and global thermal deformation, so that the rejection rate of products is high or huge labor cost is required to be consumed for post-welding correction. Accordingly, there is a need in the art to address the above-described technical problems. Disclosure of Invention In view of the problems that the existing welding equipment lacks a seam self-adaptive adjustment mechanism and is easy to cause sheet burning through, seam misalignment and collapse and heat accumulation induced deformation caused by continuous welding, the invention provides the following technical scheme for solving the technical problems: The invention provides an automatic welding method for cabinet metal plates, which comprises the following steps, S1, a main control computer plans a data acquisition frame of laser scanning in advance according to the travelling speed and the travelling direction of a multi-axis linear moving mechanism, acquires point cloud data in the data acquisition frame through a single-line laser contour sensor arranged in front of an arc welding gun, and calculates the real gap width of a machine cabinet sheet metal seam and the height difference between two sheet metals; S2, the main control computer synchronously sends control instructions to the digitally controlled welding machine and the multi-axis linear movement mechanism according to the variation of the real gap width, and the walking speed of the multi-axis linear movement mechanism is increased in the same proportion while the wire feeding speed of the welding machine is increased; S3, the main control computer controls the arc welding gun to shift to the side of the sheet metal with the lower position according to the height drop, and controls the arc welding gun to increase the residence time on the side of the sheet metal with the lower position when swinging left and right; And S4, accumulating the total heat output to the metal plate in the whole welding process in real time by the main control computer, sending a voltage reducing instruction to the digitally controlled welding machine when the total heat reaches a preset deformation critical point, simultaneously improving the running speed of the multi-axis linear movement mechanism, and starting a follow-up cooling nozzle positioned behind the arc welding gun to perform targeted cooling. The method for automatically welding the cabinet sheet metal comprises the following steps that the main control computer obtains the current motion parameters of the mobile executing mechanism and the sampling period of the vision sensor, predicts the physical position interval of an area to be welded at the next moment based on the current motion parameters and the sampling period, and defines the dynamic acquisition area based on the physical position interval, so that the vision sensor is controlled to only extract and process contour data in the dynamic acquisition area, and ambient light and splash interference outside the area are shielded. The method for automatically welding the cabinet sheet metal comprises the following steps that S1, the main control compu