Welding Robot Its Stability And Can Improve The Welding Quality And Productivity
The welding robot is an advanced welding equipment developed on the basis of industrial robots. Its main advantage lies in its stability and can improve the welding quality and productivity, and improve the working conditions of the workers. In the manufacture of power station boilers, one of the important parts of high temperature and high pressure is one of the important parts in the container shell. The length of the box shell is usually welded with a large number of tightly connected pipes, some short pipe joints with length less than 300mm, some long pipe joints The In view of the current situation, most of the welding of domestic long-term container joints still remain in the electrode arc welding level, the use of welding robots can eliminate the impact of human factors on product quality, to ensure product quality.
1. Composition and characteristics of welding robot system
The welding robot workstation is made up of the Japanese motomansk-16 arc welding robot and the yasnac mrc ii controller and the corresponding welding power supply, wire feeding mechanism, cooling system and preheating device.
motomansk-16 arc welding robot mechanism for the vertical multi-articular shape, with 6 degrees of freedom, repeat the positioning accuracy of plus or minus 0.1 mm, each axis are used ac servo motor drive, the maximum weight of 6 kg.
Robot with a welding torch and the corresponding wire structure, water, gas, through the programmer input instructions, the implementation of welding procedures to achieve the welding of pipe joints. The controller memory capacity can perform 2 200 steps. In the teaching state of the program, the main program can be added to the welding process, trolley moving procedures and filigree, clean up the nozzle program, to achieve a number of continuous welding pipe joints.
For the thicker alloy steel tube box, the welding process requires preheating and postheating of the workpiece. The heating device installed in the robot trolley, the heating time and the distance of the heating gun can be set in the main program. Welding is due to continuous welding, conductive resistance heat is very high, welding heat generated when the larger, so in order to avoid overheating welding torch, in addition to the system in the use of closed water purification cooling system, in addition to the program to join the filigree The In this way, on the one hand to prevent corrosion; the other hand, there will be no dirt blocking the nozzle affect the wire and aspiration.
For different diameter of the box, you can use the design of the highly adjustable v-shaped frame to ensure that the parts to be welded in the same height.
2. Determination of teaching trajectory
Arc welding robot is in strict accordance with the operator to prepare the teaching procedures to complete the action trajectory. Usually according to the diameter of the pipe to choose the first circle 5 to 8 teaching points, according to the depth and width of the weld groove to determine the way the weld and the number of welding layers. Before the teaching of the preferred welding gun positioning and reference point settings, and then through the programmer to complete the welding process of teaching programming.
3. Setting and control of welding parameters
Since the pipe joint and the cartridge cylinder are round workpieces, the depth and width of the groove are varied over the entire circumference. In order to ensure that the welding metal after welding evenly fill the groove, in addition to sub-section set welding current, arc voltage, but also according to the need for different locations of the welding speed were set.
In addition, the welding process according to the formation of different groove can be used sub-road welding, swing welding and other processes. When the wobble welding, should choose the corresponding conditions of the welding conditions, through the provision of welding shape, the speed of welding, welding amplitude and frequency and other parameters, to achieve swing welding function.
The arc welding process can be controlled and managed by welding auxiliary condition documents.
Before welding, the reference point is set so that the user coordinate system is reset before each welding. The welding procedure can be translated as the center of the reference point. The detector at the front of the robot detects the vertical and horizontal positional deviation of the header by detecting the header and the pipe joint, and corrects it in the welding system. Because of its high repeatability, it can eliminate the need for machining and The error of the welded pipe joint. At the same time because of its high precision reproduction, a set of welding procedures, as long as the welding box diameter, pipe joints of the same diameter, you can repeatedly apply the same teaching procedures, without repeated teaching, it can greatly improve production efficiency.
In addition, in the workpiece placement and welding heating process will inevitably appear horizontal, vertical and deflection direction deviation, in addition to the detector through the inspection, you can also set the hosei program to achieve dynamic changes, Welding bias to make up.
4. Common defects prevention measures and application examples
(1) common defects to prevent measures In the robot welding, often resulting in defects mainly stomatal, undercut, non-fusion layer and welding and so on.
Robot welding is used ar + co2 mixed gas shielded welding, ar gas and co2 gas mixing ratio is 4: 1. The main reason for the formation of the stomata is the gas flow is too large, or the air is not smooth air flow caused by too small and gas and so on. In this way, in addition to the welding before the careful examination of the gas dryer is energized, adjust the gas flow, the welding process should also regularly clean the nozzle to prevent splash blocking the gas path caused by stomata.
Improper teaching position may also lead to stomatal, welding and non-fusion welding defects such as the need to continue to explore in practice, the accumulation of experience, so that teaching point closer to perfection. Robot welding common defects and precautions.
(2) Application example At the end of 2000 the company in the Fushun boiler project header joint manufacturing for the first time the successful application of the robot for pipe joints welding. The size of the product set is 426 mmx20 mmx9 000 mm diameter; pipe fittings specifications for the diameter of 89 mmx7 mm, length of 120 mm; pipe joint welding net spacing of 200 mm, the average number of 90 sets of each tube tube joints. The entire welding process is stable and the weld is beautiful.
After the welding of the product samples for macro inspection, welding joint fusion is good.