CN114309934A - A method for automatic laser welding of frame skin box-like structures - Google Patents

Abstract

The invention discloses a laser automatic welding method for a frame skin box structure, which comprises the following steps: clamping a product to be welded of a first workpiece; establishing a base coordinate system according to the position of a first product to be welded; teaching and storing coordinates of teaching points in all independent teaching programs on a welding track of a first product to be welded in a base coordinate system; writing a general program, and calling independent teaching programs in sequence according to a welding sequence; clamping the next product to be welded with the same model; updating the original point of the base coordinate system at the actual position of the next product to be welded with the same model to obtain a base' coordinate system; trial running the total program in a base' coordinate system; and welding after checking without errors. The invention can realize laser automatic welding, does not need special off-line programming software or a simulation system when editing programs, and can adapt to the size and position inconsistency which is possibly existed on a laser welding positioner by a plurality of products with the same type and exceeds the requirement of laser welding positioning accuracy.

Description

A method for automatic laser welding of frame skin box-like structures

technical field

The invention belongs to the technical field of laser welding, and in particular relates to a laser automatic welding method for a frame skin box-like structure.

Background technique

The frame skin form is a common form of box-like structures in the aerospace field. The frame is used as a load-bearing skeleton to assemble the skin and then perform integral welding. With the development of aviation weapons and equipment technology, higher and higher requirements are put forward for the dimensional accuracy of structural parts. Therefore, higher and higher requirements are also put forward for the pre-welding assembly accuracy of the structure, the design of welding tooling and the control of welding deformation.

As a high-energy beam welding method, laser welding has the advantages of high welding energy density, large aspect ratio, small welding deformation, narrow welding heat-affected zone, fast welding speed and beautiful weld formation. In addition, compared with electron beam welding, the equipment investment cost is low, the welding operation flexibility is high, and it is free from vacuum environment.

The processing methods of the laser welding workstation can be divided into two types: manual teaching and offline programming. At present, the processing method of most workstations at home and abroad is still manual teaching, which has the disadvantages of cumbersome teaching process and low efficiency, and the accuracy of manual teaching is determined by the operator's experience and visual inspection. The offline programming automatic welding technology is expected to realize the effect of automatic walking and welding of the robot according to the predetermined trajectory through the offline programming system and the simulation system, avoiding the disadvantages of manual teaching. However, the offline programming technology of domestic industrial robots is still immature, and the truly practical offline programming system has not been reported on welding robots except for the application of assembly robots.

The diameter of the laser welding spot is small (1mm~2mm), and the welding positioning accuracy is high (within 0.2mm). In actual industrial mass production, the assembly deviation may exceed the welding positioning accuracy requirements. Therefore, offline programming laser automatic welding There are still difficulties to be overcome in the promotion in practical industrial applications.

SUMMARY OF THE INVENTION

The technical solution of the present invention is to overcome the deficiencies of the prior art, and to provide a laser automatic welding method for a frame skin box-like structure, which can realize automatic laser welding, and does not need to use special offline programming software or a simulation system when editing a program. It can adapt to the inconsistency of the size and position of multiple products on the laser welding positioner that exceeds the requirements of laser welding positioning accuracy.

In order to solve the above technical problems, the present invention discloses a laser automatic welding method for frame skin box structure, including:

Clamp the first product to be welded;

The base coordinate system is established with the position of the first product to be welded;

In the base coordinate system, teach and store the coordinates of the teaching points in all independent teaching blocks on the welding track of the first product to be welded;

Write the general program, and call the independent program segments in sequence according to the welding sequence;

Clamp the next product to be welded; among them, the next product to be welded and the first product to be welded belong to the same type of product;

The actual position of the following product to be welded updates the origin of the base coordinate system to obtain the base' coordinate system;

Trial run the total program in base' coordinate system;

Welding is carried out after inspection.

In the above-mentioned automatic laser welding method of frame skin box structure, it also includes: arranging a special connection structure connected with the laser welding positioner on the welding tool to ensure the uniqueness of the clamping and ensure that each product to be welded is laser welded. The consistency of the clamping position and angle on the positioner.

In the above-mentioned automatic laser welding method of frame skin box structure, clamping the first product to be welded includes: clamping the first product to be welded and the welding tool on the laser welding positioner as a whole to ensure the clamping angle and position uniqueness.

In the above-mentioned automatic laser welding method of frame skin box structure, when clamping the next product to be welded, the same clamping method as the first product to be welded is adopted to ensure the clamping position of the next product to be welded. , The angle is consistent with the clamping position and angle of the first product to be welded.

In the above-mentioned automatic laser welding method of frame skin box structure, the base coordinate system is established based on the position of the first product to be welded, including:

Determine the position and dimensional accuracy of each feature point on the first product to be welded;

Select the feature point with the highest position and dimensional accuracy as the coordinate origin to establish the base coordinate system.

In the above-mentioned automatic laser welding method for a frame-skin box-like structure, the relative position error between the feature point and the head to be welded is within 0.2 mm.

In the above-mentioned automatic laser welding method of frame skin box structure, in the base coordinate system, teach and store the coordinates of the teaching points in all the independent teaching program segments on the welding track of the first product to be welded, including: mobile welding robot Go to the starting point of the laser welding path, record the coordinates of this point in the base coordinate system; teach the teaching points on all the teaching programs on the welding track of the first product to be welded in the base coordinate system, and each teaching program is used as an independent display. The teaching block stores the coordinates of the teaching point.

In the above-mentioned automatic laser welding method of frame skinned box structure, the general program is written, and the independent program segments are called in sequence according to the welding sequence, including: integrating the original independent teaching program segments into a program, calling them in sequence according to the welding sequence, and Save as a template program.

The present invention has the following advantages:

(1) The present invention discloses a laser automatic welding method for frame skin box structure, which can realize laser automatic welding, does not need to use special offline programming software or simulation system when editing the program, and can adapt to the laser welding of multiple products. There may be inconsistencies in the size and position of the positioner that exceed the requirements of laser welding positioning accuracy.

(2) The present invention discloses a method for automatic laser welding of frame skin box-like structures, which reduces the number of manual teaching and realizes automatic laser welding to a certain extent when the domestic offline programming technology is still immature.

(3) The present invention discloses a method for automatic laser welding of a frame skin box structure. Using the method of the present invention to perform automatic laser welding, after calibrating the base' coordinates with the characteristic points of each product to be welded, run the total The program realizes the laser automatic welding of the circumference or the whole welding joint, free from the use of special offline programming software or simulation system.

Description of drawings

1 is a flow chart of the steps of a method for automatic laser welding of a frame-skin box-like structure in an embodiment of the present invention;

FIG. 2 is an example diagram of automatic laser welding of butt joints around a frame/sheet-welded skin structure box body in an embodiment of the present invention;

FIG. 3 is an example diagram of automatic laser welding of butt joints around a frame/extruded skin structure box body in an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

In this embodiment, as shown in FIG. 1 , the automatic laser welding method of the frame skin box structure includes:

Step S1, clamping the first product to be welded.

In this embodiment, a special connection structure for connecting with the laser welding positioner is provided on the welding tool. The setting of the special connection structure can ensure the uniqueness of the clamping and ensure that each product to be welded is connected to the laser welding positioner. Consistency of clamping position and angle.

Preferably, when clamping the first product to be welded, the first product to be welded and the welding tool are integrally clamped on the laser welding positioner to ensure the uniqueness of the clamping angle and position.

In step S2, a base coordinate system is established based on the position of the first product to be welded.

In this embodiment, first, the position and dimensional accuracy of each feature point on the first product to be welded is determined; then, the feature point with the highest position and dimensional accuracy is selected as the coordinate origin to establish a base coordinate system. Among them, the relative position error between the feature point and the head to be welded is within 0.2mm.

Step S3, in the base coordinate system, teach and store the coordinates of the teaching points in all the independent teaching program segments on the welding track of the first product to be welded.

In this embodiment, move the welding robot to the starting point of the laser welding path, record the coordinates of this point in the base coordinate system; teach the teaching points on all teaching programs on the welding track of the first product to be welded in the base coordinate system , and each segment of the teaching program stores the coordinates of the teaching point as an independent teaching segment.

In step S4, a general program is written, and the independent program segments are sequentially called according to the welding sequence.

In this embodiment, the original independent teaching program segments are integrated into one program, called sequentially according to the welding sequence, and stored as a template program.

Step S5, clamping the next product to be welded.

In this embodiment, when clamping the next product to be welded, the same clamping method as the first product to be welded is used to ensure that the clamping position and angle of the next product to be welded are the same as those of the first product to be welded. The clamping position and angle are the same.

Step S6, the actual position of the next product to be welded is updated to the origin of the base coordinate system to obtain the base' coordinate system.

Step S7, try to run the total program in the base' coordinate system.

In step S8, welding is performed after checking that it is correct.

On the basis of the above embodiment, a detailed implementation process is taken as an example for description below.

In this embodiment, the laser automatic welding method is carried out according to the following process steps:

(1) Sample clamping: The first piece of product to be welded and the welding tooling are fully clamped on the laser welding positioner to ensure the uniqueness of the clamping angle and position.

Preferably, the position and angle consistency of each product to be welded on the welding positioner can be achieved by means of the special connection structure and the connection and cooperation between the tooling and the positioner.

(2) Establish the base coordinate system: take a feature point on the first product to be welded as the base coordinate origin, establish the base coordinate system, and select the convenient x, y, and z directions accordingly.

Preferably, the feature points are selected as points on the first product to be welded with high relative positional accuracy to the head to be welded. For example, feature points whose relative position error with the head to be welded is within 0.2mm.

(3) Teach the sample welding trajectory: move the welding robot to the starting point of the laser welding path, and record the coordinates of this point in the base coordinate system; teach the first piece of the product to be welded on the welding trajectory of all teaching programs in the base coordinate system. Teaching point, each teaching program stores the coordinates of the teaching point as an independent teaching block.

Preferably, each independent teaching program segment, such as D1(), D2(), etc., is a basic teaching program such as a straight line and an arc used in manual teaching, and can independently complete basic trajectories such as a straight line segment or an arc segment. welding, including the basic steps of air supply, light output, arc starting, arc ending, light off, and gas off.

(4) General program editing: Integrate the original independent teaching blocks into one program, call them in sequence according to the welding sequence, and store them as a template program.

Preferably, the program integration is available: "INI D1() D2() D3()...Dx()" statements call each independent teaching block D1() D2() D3()...Dx().

(5) Clamping the next product to be welded: Clamp the next product to be welded in the same way as in step (1) to ensure the same clamping position and angle as the first product to be welded.

(6) Calibrate the coordinate system: move the laser welding robot to the feature point on the next product to be welded, and re-calibrate the feature on the next product to be welded as the coordinate origin to establish the base' coordinate system.

(7) Automatic laser welding of products: run the template program in the base' coordinate system, automatically move the welding robot to the welding starting point, check the alignment of the laser focus of the welding robot and the laser welding joint at this time, and try to run the general program.

Preferably, if the starting point in the general laser automatic welding program deviates from the actual product welding starting point, the base' coordinate system can be manually modified to calibrate the welding position.

A possible modification is:

Measure the deviation between the starting point in the laser automatic welding template program and the actual product welding starting point in X, Y, and Z directions, and define the starting point on the product to be welded as XP1 and the starting point on the product to be welded as XP2, there are:

Pianyi_A=XP2.A-XP1.A

Pianyi_B=XP2.B-XP1.B

Pianyi_C=XP2.C-XP1.C

Pianyi_X=XP2.X-XP1.X

Pianyi_Y=XP2.Y-XP1.Y

Pianyi_Z=XP2.Z-XP1.Z

and then:

base_data'.A=Base_data'.A+Pianyi_A

base_data'.B=Base_data'.B+Pianyi_B

base_data'.C=Base_data'.C+Pianyi_C

base_data'.X=Base_data'.X+Pianyi_X

base_data'.Y=Base_data'.Y+Pianyi_Y

base_data'.Z=Base_data'.Z+Pianyi_Z

After calibrating the base coordinates, recheck whether the starting point in the automatic laser welding program is consistent with the welding starting point of the product to be welded.

(8) Laser automatic welding: After the inspection is correct, the laser automatic welding of the circumferential welding track is completed.

On the basis of the above-mentioned embodiment, the following takes the laser automatic welding process of the frame/sheet-welded skin structure box by adopting the solution of the present invention as an example for description.

The overall section of the frame/welded skin structure box is nearly square, and the end frame is a machined structural part with a dimensional accuracy of ±0.1mm, and the skin is a mechanically processed structural part with a dimensional accuracy of ±0.2mm. The cross-section of the welded joint and the welding sequence are shown in Figure 2.

Assemble the first box to be welded on the welding tool, and measure the unevenness of the four corners of the box to ensure that it is within 0.5mm. The first box to be welded is clamped and fixed with the welding positioner, and the uniqueness of the clamping position and angle is guaranteed by the structural design of the joint. Taking the "0" point shown in Figure 2, that is, a certain feature point on the butt joint between the end frame and the skin, as the origin of the base1 coordinate system, according to the right-hand rule of the space coordinate system, set the base1 coordinate y-axis parallel to the welding direction, Set the base1 coordinate x-axis perpendicular to the welding direction, and set the z-axis perpendicular to the welding plane to establish the base1 coordinate system. In this coordinate system, the original 15 independent teaching programs C1()C2()C3()...C15() are calibrated in sequence according to the welding sequence shown in Figure 2, and the positions of the manual teaching points are stored in the program. middle.

Write the general program:

Call C1()C2()C3()...C15() teaching blocks in sequence according to the welding sequence. Trial run the general program, check that the welding robot's running trajectory is correct, and complete the welding. Assemble the subsequent box products to be welded to ensure the same clamping position and angle as the first set of box products on the laser welding positioner. Use the base1 coordinate system, under this coordinate system, take the feature point at the same position on the upper end frame of this set of products and the skin butt joint as the base1 coordinate origin, update the coordinate system base1', and set x in the same direction as the first set of products. , y, z direction, base1 coordinate system calibration is completed. Directly run the general program in the base1' coordinate system to check whether there is any deviation between the laser welding robot's running trajectory, defocusing amount and the laser inclination angle. After checking, run the general program to automatically complete the welding of the peripheral weld.

On the basis of the above-mentioned embodiments, the following description will be given by taking the laser automatic welding process of the butt joint of the frame/extruded skin structure box perimeter ring as an example for description.

The overall section of the box body is nearly trapezoidal, the end frame is a machined structural part with a dimensional accuracy of ±0.1mm, and the skin is a thermoformed structural part with a dimensional accuracy of ±0.5mm. The cross-section and sequence of welded joints are shown in Figure 3.

After the first set of the box to be welded is assembled on the welding tool, it is firmly clamped on the positioner, and the clamping position angle is fixed by the connecting mechanism. The midpoint of the edge of the end frame is set as the origin of the base2 coordinate. According to the right-hand rule of the space coordinate system, the direction parallel to the edge of the end frame is the y direction, the direction perpendicular to the edge of the end frame is the x direction, and the plane of the vertical end frame is the z direction, and the base2 coordinates are established. . In this coordinate system, calibrate the independent arc segment teaching programs D1(), D2(), D3(), D4(), and the straight line segment teaching programs D5(), D6(), D7(), D8(), store the calibration point position in the program.

Write the general program:

Call the independent teaching programs in sequence according to the welding sequence, d1()d2()d3()...d8(). Trial run the general program, check that the welding robot's running trajectory is correct, and complete the first set of product welding. Assemble the subsequent box products, and connect them with the laser welding positioner through the connecting mechanism to ensure the same clamping position angle as the first set of box products. Re-calibrate the base2 coordinate origin with the feature point of the midpoint of the edge of the end frame of this set of products, and set the x, y, and z directions in the same direction as the first set of products, and the base2' coordinate system calibration is completed. Trial run the general program to check whether there is any deviation between the laser welding robot's running trajectory, defocusing amount and the laser inclination angle. According to the welding starting point, it is found that the actual welding starting point XP2 of the product does not coincide with the welding starting point XP1 of the welding robot, namely:

Pianyi_A=XP2.A-XP1.A

Pianyi_B=XP2.B-XP1.B

Pianyi_C=XP2.C-XP1.C

Pianyi_X=XP2.X-XP1.X

Pianyi_Y=XP2.Y-XP1.Y

Pianyi_Z=XP2.Z-XP1.Z

Manually update base2' coordinate origin position:

base_data[2].A=Base_data[2].A+Pianyi_A

base_data[2].B=Base_data[2].B+Pianyi_B

base_data[2].C=Base_data[2].C+Pianyi_C

base_data[2].X=Base_data[2].X+Pianyi_X

base_data[2].Y=Base_data[2].Y+Pianyi_Y

base_data[2].Z=Base_data[2].Z+Pianyi_Z

Trial run the general program, check the running track of the welding robot, run the general program after correct, and automatically complete the laser welding of the peripheral weld.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can use the methods and technical contents disclosed above to improve the present invention without departing from the spirit and scope of the present invention. The technical solutions are subject to possible changes and modifications. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention belong to the technical solutions of the present invention. protected range.

Contents that are not described in detail in the specification of the present invention belong to the well-known technology of those skilled in the art.

Claims (8)

1. a frame skin box type structure laser automatic welding method, is characterized in that, comprises: Clamp the first product to be welded; The base coordinate system is established with the position of the first product to be welded; In the base coordinate system, teach and store the coordinates of the teaching points in all independent teaching blocks on the welding track of the first product to be welded; Write the general program, and call the independent program segments in sequence according to the welding sequence; Clamp the next product to be welded; among them, the next product to be welded and the first product to be welded belong to the same type of product; The actual position of the following product to be welded updates the origin of the base coordinate system to obtain the base' coordinate system; Trial run the total program in base' coordinate system; Welding is carried out after inspection. 2. The method for automatic laser welding of frame-skin box-like structures according to claim 1, further comprising: setting a special connection structure connected to the laser welding positioner on the welding tool to ensure the uniqueness of the clamping , to ensure the consistency of the clamping position and angle of each product to be welded on the laser welding positioner. 3. The method for automatic laser welding of frame-skin box-like structures according to claim 2, wherein the clamping of the first product to be welded comprises: clamping the first product to be welded and the welding tool on the laser welding machine as a whole. On the positioner, the uniqueness of the clamping angle and position is guaranteed. 4. The laser automatic welding method for frame skin box structure according to claim 3, characterized in that, when clamping the next product to be welded, the same clamping method as the first product to be welded is adopted to ensure that The clamping position and angle of the next product to be welded are the same as the clamping position and angle of the first product to be welded. 5. The method for automatic laser welding of frame-skin box-like structures according to claim 1, wherein the base coordinate system is established with the position of the first product to be welded, comprising: Determine the position and dimensional accuracy of each feature point on the first product to be welded; Select the feature point with the highest position and dimensional accuracy as the coordinate origin to establish the base coordinate system. 6 . The automatic laser welding method for frame-skin box-like structures according to claim 5 , wherein the relative position error between the feature point and the head to be welded is within 0.2 mm. 7 . 7. The method for automatic laser welding of frame-skin box-like structures according to claim 1, characterized in that, in the base coordinate system, teaching and storing all the independent teaching program segments on the welding track of the first product to be welded The coordinates of the teaching point, including: moving the welding robot to the starting point of the laser welding path, recording the coordinates of this point in the base coordinate system; teaching the teaching of all teaching programs on the welding track of the first product to be welded in the base coordinate system point, each teaching program as an independent teaching block stores the coordinates of the teaching point. 8 . The method for automatic laser welding of frame, skin, box-like structures according to claim 1 , wherein writing a general program and sequentially calling independent program segments according to the welding sequence, comprising: integrating the original independent teaching program segments into one In the program, they are called in sequence according to the welding sequence and stored as a template program.

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