CN106002010A - Automatic robot welding and deformation controlling method for box type structural members made of HG785D plates - Google Patents

Abstract

The robot automatic welding and deformation control method of HG785D sheet metal box-shaped structural parts belongs to the welding technology field of truck chassis, crane lifting arm and various high-strength load-bearing beams. Robotic automatic welding technology with consistent weld position and dimensional accuracy of structural parts, the technical content adopted: follow the following steps: 1. Laser cutting the shape of the cover plate, vertical plate, bottom plate and channel steel of box-shaped structural parts, The tolerance is controlled within ±0.5mm; 2. The shape of the parts after the first step of laser cutting is corrected, and the flatness is controlled within 1mm; 3. The parts after the second step of calibration are assembled into a box-shaped structure through the assembly positioning device 4. The robot uses the welding positioning device to weld and position the box-shaped structural parts assembled in the third step; 5. The robot uses the mature welding process parameters at the test board level to weld the box-shaped structural parts after the fourth step of positioning; The invention is applied to the automatic welding of box-shaped structural beams.

Description

Robot automatic welding and deformation control method for HG785D plate box structure parts

technical field

The HG785D robot automatic welding and deformation control method for plate box-shaped structural parts belongs to the welding technical field of truck chassis, crane lifting arms, and various high-strength load-bearing beams.

Background technique

The box-shaped structural part is the main component of the product, consisting of a cover plate, a vertical plate, a bottom plate and a channel steel (see Figure 1 for specific structure, size and weld requirements). The main material is HG785D low-alloy high-strength welded steel plate with a thickness of 6mm and 8mm (see Table 1 for the mechanical properties of HG785D steel plate).

HG785D steel plate is a low-alloy high-strength steel plate for welding structures independently developed in China. This material has the characteristics of high strength, high elasticity, excellent mechanical properties and welding performance. Load-bearing beams and other welded structures that require high strength, high bending resistance, high torsion resistance, light weight and super heavy load. At present, the common welding methods for this material are mainly electrode arc welding and semi-automatic gas shielded welding. The welding method is backward, the production efficiency is low, and the welding quality and welding deformation are not easy to control.

In recent years, the development of manufacturing industries such as aerospace, transportation, ocean engineering, and electronic appliances has greatly promoted the development of welding technology. Welding robots have controllable welding processes, stable welding parameters, high welding speed, and easy production. Features such as automation and improvement of workers' working conditions have shown great vitality. As an irreplaceable important equipment and means in advanced manufacturing, it has become one of the important symbols to measure the manufacturing level and technological level of a country or an enterprise. In order to improve product welding production efficiency, improve welding quality, reduce welding deformation, reduce labor intensity of workers, and improve the advanced manufacturing level of enterprises, it is necessary to introduce a robot welding system to carry out robot welding research on box-shaped structural parts made of HG785D steel plate, but At present, robot welding is mainly used in the welding structure of ordinary plates. For the welding of high-strength steel plates, the research level remains at the test plate level, and there is still a lack of research on how to successfully apply it to product welding structures.

From Figure 1, we can see that its structure is a box-shaped structure. There are mainly 4 welds in the structure, the lengths are 1070mm and 1325mm, and the height of the weld angle is 6mm. There are few welds and the height of the weld angle is not large, but the welds are The length and width of the structure are symmetrical, and the height direction is asymmetrical. The distance between the weld between the vertical plate and the cover plate and the central axis is relatively large, and the distance between the vertical plate and the bottom plate is relatively small.

According to the structural characteristics and assembly requirements, the possible problems of robot welding for such structures mainly include:

a. The large deviation of the outer dimensions of the parts and the poor flatness cause the assembly gap to be too large, and the robot cannot weld;

b. The reserved length of the part is unreasonable, and the welding process causes the shrinkage in the length direction, resulting in the failure to guarantee the quality of the subsequent welding with the longitudinal beam;

c. Distortion or upward deflection caused by improper welding sequence;

d. At present, the common robot welding belongs to the "trial-teaching-reproduction" robot, with a low level of intelligence, and mainly operates according to the path and requirements of the program. The positioning accuracy of assembly and welding is poor, which cannot meet the repeated positioning requirements of robots.

Contents of the invention

The technical problem to be solved by the present invention is to provide a robotic automatic welding technology that satisfies the consistency of weld position and dimensional accuracy of HG785D plate box-shaped structural parts.

The structure of the box-shaped structural member in the present invention is as follows: two vertical plates are arranged side by side, the cover plate is located above the two vertical plates and welded together with the two vertical plates. The bottom plate is located below the two vertical plates and welded together with the two vertical plates along the lower line of the two vertical plates. There are square holes near both ends of the two vertical plates, and the opposite two square holes form a group. A channel steel component is interspersed and fixed in the two groups of square holes, and the channel steel component is two channel steels relatively fixed together. What the present invention aims to solve is the robot automatic welding technology of the weld seam between the cover plate and the vertical plate, and between the bottom plate and the vertical plate.

In order to solve the above-mentioned technical problems, the technical content adopted in the present invention: The robot automatic welding and deformation control method of the HG785D plate box-shaped structural part is carried out according to the following steps:

1. The shape of the cover plate, vertical plate, bottom plate and channel steel of the box-shaped structural parts are respectively cut and formed by laser, and the tolerance is controlled within ±0.5mm. According to the cover plate, vertical plate, bottom plate and the box-shaped structure To determine whether the vertical plate, bottom plate, and cover plate are reserved in the length direction and the reserved length according to the grouping relationship between other structural parts connected by the component and the difference in welding seam requirements;

2. Correct the shape of the cover plate, vertical plate, bottom plate and channel steel after the first step of cutting, and control the flatness within 1mm;

3. Assemble the cover plate, vertical plate, bottom plate and channel steel after the second step of shaping into a box-shaped structural part by assembling the positioning device;

4. The robot welds and positions the box-shaped structural parts assembled in the third step through the welding positioning device;

5. The robot uses the mature welding process parameters at the test board level to weld the box-shaped structural parts after the fourth step of positioning; during the welding process, the welds that are closer to the neutral axis are welded first, and then the welds that are farther away from the neutral axis are welded. welds, and all welds start in the same direction.

In the first step, a welding shrinkage margin of 1 mm is reserved in the length direction of the vertical plate and the bottom plate, and no reserve is made in the length direction of the cover plate.

In the third step, the bottom plate and the vertical plate are selected as the positioning reference, and the positioning accuracy is controlled within ±0.5mm.

In the welding process in the fifth step, the weld seam between the cover plate and the two vertical plates is welded first, and then the weld seam between the bottom plate and the two vertical plates is welded.

Compared with the prior art, the present invention has the following beneficial effects.

1. Robot welding belongs to the "trial-reproduction" type of robot, which has high requirements on the consistency of weld position and dimensional accuracy of structural parts, which requires parts to have high forming accuracy, assembly accuracy and positioning accuracy. Therefore, determining reasonable welding process parameters, part forming accuracy, assembly welding sequence, and assembly welding positioning accuracy is the key to realizing robot automatic welding and deformation control.

The present invention starts from the key point and actual operation of automatic robot welding and deformation control, analyzes the influence of part forming accuracy, assembly positioning accuracy and welding positioning accuracy on welding quality and production efficiency, and adopts laser cutting to control part accuracy, reasonable Arranging the assembly and welding sequence, developing assembly and welding positioning process equipment and other process integration methods, realized the automatic welding and deformation control of HG785D box-shaped structural parts robot, and improved the automation level of product production.

2. Box-type structural parts The assembly sequence of structural parts can be taken in three ways: ① T-type → groove type → box type; ② groove type → box type; ③→②→①, based on the principle that the greater the stiffness, the smaller the welding deformation, the present invention adopts the third assembly, which greatly reduces the influence on the welding deformation.

3. In the welding process of the present invention, the weld seam closer to the neutral axis is welded first, so that the welding deformation is small; all weld seams are welded from the same direction, which can avoid distortion and deformation.

4. The present invention selects the bottom plate and vertical plate with high processing precision as the positioning reference, and the positioning accuracy is controlled within ±0.5mm, which satisfies the assembly positioning accuracy and welding positioning accuracy, so that the robot automatic welding can be realized smoothly.

5. The robot welding adopts the mature welding process parameters at the test board level, which effectively guarantees the welding quality.

Description of drawings

Figure 1 is a structural schematic diagram of a box-shaped structural member.

FIG. 2 is a side view of FIG. 1 .

Among the figure, 1 is a base plate, 2 is a vertical plate, and 3 is a cover plate.

detailed description

As shown in Figure 1 and Figure 2, the robot automatic welding and deformation control method of HG785D plate box-type structural parts is carried out according to the following steps:

1. The shape of the cover plate 3, vertical plate 2, bottom plate 1, and channel steel of the box-shaped structural member are cut and formed by laser, and the tolerance is controlled within ±0.5mm. According to the cover plate 3, vertical plate 2, bottom plate 1 and The combination relationship between other structural members connected with the box-shaped structural member and the difference in welding seam requirements determine whether the vertical plate 2, the bottom plate 1, and the cover plate 3 are reserved in the length direction and the reserved length;

2. Correct the shape of the cover plate 3, vertical plate 2, bottom plate 1, and channel steel after the first step of cutting, and control the flatness within 1mm;

3. Assemble the cover plate 3, vertical plate 2, bottom plate 1, and channel steel after the second step of shaping into a box-shaped structural member by assembling the positioning device;

4. The robot welds and positions the box-shaped structural parts assembled in the third step through the welding positioning device;

5. The robot uses the mature welding process parameters at the test board level to weld the box-shaped structural parts after the fourth step of positioning; during the welding process, the welds that are closer to the neutral axis are welded first, and then the welds that are farther away from the neutral axis are welded. welds, and all welds start in the same direction.

In the first step, a welding shrinkage margin of 1mm is reserved in the length direction of the vertical plate 2 and the bottom plate 1, and no reserve is made in the length direction of the cover plate 3.

In the third step, the bottom plate 1 and the vertical plate 2 are selected as the positioning reference, and the positioning accuracy is controlled within ±0.5mm.

In the welding process in the fifth step, the weld seam between the cover plate 3 and the two vertical plates 2 is welded first, and then the weld seam between the bottom plate 1 and the two vertical plates 2 is welded.

In the first step, when the welding shrinkage margin is reserved or not and the reserved length is determined, the pairing relationship and welding seam requirements are: the box-shaped structural part is used as a beam, and it must be welded with the longitudinal beam, and the box-shaped structural part is neutral. The welds between the plate 2, the bottom plate 1 and the longitudinal beams are fillet welds, and the welds between the cover plate 3 and the longitudinal beams are single-side groove butt welds.

In the present invention, according to the assembly accuracy and repeated positioning requirements of robot welding, assembly positioning and welding positioning process equipment are equipped, wherein the assembly positioning device described in the third step includes a horizontal operating table, two pads, a first movable clamp, The second movable clamp, the third movable clamp, the C-shaped clamp, the first positioning component, the second positioning component and the third positioning component;

The two pads, the first movable clamp, the second movable clamp, the third movable clamp, the C-shaped clamp, the first positioning assembly, the second positioning assembly and the third positioning assembly are all installed on the horizontal operating table top;

The two pads are simultaneously arranged at both ends of the bottom of the box-shaped structural member to adjust the height of the box-shaped structural member, and the C-shaped clamp is simultaneously arranged in the middle of the box-shaped structural member. The first movable clamp , the second moving clamp, and the third moving clamp are respectively arranged in the length direction and the width direction of the box-shaped structural member, and the first positioning assembly, the second positioning assembly, and the third positioning assembly are respectively arranged in the box-shaped structural member. Both ends are used to locate the position of the box-shaped structural member in the length direction and width direction.

Wherein the welding positioning device described in the fourth step includes two pads arranged at intervals at the bottom of the box-shaped structural member, positioning pins arranged at both ends of the box-shaped structural member and an adjusting bolt arranged on one side of the middle of the box-shaped structural member, A pressing plate that can move up and down along the adjusting bolt is arranged on the upper part of the adjusting bolt.

Using the mature welding process parameters at the test plate level, according to the above technical scheme, two sets of 1:1 product parts were put into the welding production verification, and the weld quality and longitudinal shrinkage were tested.

The test equipment is composed of REIS robot, EWM welding power supply, REIS positioner, etc. The rotation and flip of the positioner are controlled by the robot. As the external control axis of the robot, the linkage between the robot and the positioner can be realized through the robot controller. .

See Table 2 and Table 3 for the test results of weld quality and longitudinal shrinkage.

It can be seen from the test results that the welding quality of the product meets the requirements of the indicators, the allowance for welding shrinkage is reasonable, and the process plan is reasonable and feasible, which can be used for automatic welding production of products.

Claims (4)

1. The robot automatic welding and deformation control method of HG785D plate box-type structural parts is characterized in that it is carried out in accordance with the following steps: 1. The shape of the cover plate, vertical plate, bottom plate and channel steel of the box-shaped structural parts are respectively cut and formed by laser, and the tolerance is controlled within ±0.5mm. According to the cover plate, vertical plate, bottom plate and the box-shaped structure To determine whether the vertical plate, bottom plate, and cover plate are reserved in the length direction and the reserved length according to the grouping relationship between other structural parts connected by the component and the difference in welding seam requirements; 2. Correct the shape of the cover plate, vertical plate, bottom plate and channel steel after the first step of cutting, and control the flatness within 1mm; 3. Assemble the cover plate, vertical plate, bottom plate and channel steel after the second step of shaping into a box-shaped structural part by assembling the positioning device; 4. The robot welds and positions the box-shaped structural parts assembled in the third step through the welding positioning device; 5. The robot uses the mature welding process parameters at the test board level to weld the box-shaped structural parts after the fourth step of positioning; during the welding process, the welds that are closer to the neutral axis are welded first, and then the welds that are farther away from the neutral axis are welded. welds, and all welds start in the same direction. 2. The robot automatic welding and deformation control method for HG785D plate box-shaped structural parts according to claim 1, characterized in that: in the first step, a welding shrinkage margin of 1mm is reserved in the length direction of the vertical plate and the bottom plate, and the cover The length direction of the plate is not reserved. 3. The robot automatic welding and deformation control method for HG785D plate box-shaped structural parts according to claim 1, characterized in that: in the third step, the bottom plate and the vertical plate are selected as the positioning reference, and the positioning accuracy is controlled within ±0.5mm . 4. The robot automatic welding and deformation control method for HG785D plate box-shaped structural parts according to claim 1, characterized in that: in the welding process in the fifth step, first weld the cover plate and the two vertical plates Weld, after welding the weld between the bottom plate and the two vertical plates.