Welding Robot Breaking The Traditional Way Of Welding Rigid Automation
Industrial robots, as the main automation equipment in modern manufacturing industry, have made revolutionary progress in welding automation, which breaks through the traditional way of welding rigid automation and opens up a new way of flexible automation. To enhance the technological level of enterprises, stabilize product quality, improve production efficiency and achieve a civilized production and so has a significant role. Over the years, with the rapid development of domestic automobile manufacturing, robot welding technology as the main means of advanced manufacturing technology can be widely used.
1 welding robot features and functions
Now widely used welding robots are the first generation of industrial robots, its basic principle is to show reproduction [3,4]. As the robot show the performance of the performance of the welding robot to complete a welding task, just a teaching, you can accurately reproduce the teaching of the action, such as the robot to do another job, without changing any hardware, just And then do a teaching can, therefore, in a welding robot production line, can automatically produce a number of welding parts, welding robot on the production conditions of adaptability is very strong. Welding robot is a programmable flexible automation equipment, flexibility is very strong, especially in a narrow space operation with six degrees of freedom of the robot, in the automotive industry attracted much attention. Figure 1 shows a mainstream brand welding robot, its main features are as follows:
1) high speed, smooth and other similar types of robots compared to the highest speed, high acceleration, thus shortening the idle time and cycle time, improve productivity.
2) wide range of action due to the use of an independent joint structure, the scope of action, the maximum extension of the distance of 1360mm, horizontal stroke range of 1017mm, and because the color of the bias wrist structure, easier access to welding parts, welding gun rotation angle increases, Thus expanding the scope of action when welding the workpiece.
3) small size, saving space in the design of the use of a place without the need to choose a compact design, the use of hollow shaft on the reducer, reducing the installation space.
4) excellent control performance, strong operation of the main controller CPU and calculus CPU independence, to ensure a more smooth high-speed movement to ensure that the track of high precision; and memory FLASH in memory, greatly improving the storage capacity.
2 Automotive cleaner shell welding example
At present, the robot in the industrial welding, especially in the automotive industry has been more and more widely used. Car purifier shell using Q235 low carbon steel plate, the shear, forming clamping, positioning, welding, hot dip infiltration made of aluminum and other technology. Low-carbon steel plate aluminizing process can replace stainless steel, and long-term use of high temperature below 900 ℃ without damage, low cost of raw materials. The purifier shell is finished by spot welding and arc welding, and the upper and lower shell interface is composed of straight weld and both ends of the flange ring weld. The workstation uses two welding stations of the robot welding system, the first purifier placed in the tooling, through the table of floating support, auxiliary support and fixture positioning and clamping by the welding robot, locator and with it Matching the surrounding facilities to each other accurately with the completion of the entire purifier process contains the welding parts of the welding. Production can also be based on equipment utilization after the use of manual spot welding by the robot automatically completed the welding process welding.
2.1 The composition and action design of welding robot workstation
The welding robot system consists of the frame (base, support seat), the table floating support, auxiliary support and fixture (2 sets of positioners, 2 stations), the robot and its control system, pneumatic system, Board, light curtain, welding power supply, welding torch, electrical system and other auxiliary devices.
2.1.1 Robot control system
As the programmable controller (PLC) is designed for the application of the factory environment designed for an industrial control computer, with anti-interference ability, high reliability, small size, is to achieve the ideal mechanical and electrical integration control device, etc., Therefore, the workstation uses it as the main control device, responsible for the centralized scheduling of the entire system, through the bus and I / O interface to obtain the status of the implementation of the elements, the welding task is divided into various sub-tasks, distribution and coordination of the work of the various stations.
The control system is mainly composed of the main control box, the main operation panel, sub-operation panel and other components, the core of the Japanese Mitsubishi programmable controller . The main control box is the center of the control, mainly to complete the coordination of the robot, the control panel; sub-operation panel with a touch screen, to complete all operations and provide a variety of instructions, power "into, cut," "manual, automatic" conversion Switch, "run ready", "abnormal release", "alarm stop", "very stop" and other buttons, as well as a variety of alarm lights; the main operation panel to complete the work start, stop control.
For the installation of welding robots, flip positioners, auxiliary support, workstations and other components. Which horizontal flip positioner drag 2 sets of fixture with welding robot so that the workpiece weld in the best welding position.
2.1.3 Pneumatic systems
Pneumatic system by the pneumatic valve, cylinder and other components, to achieve the lifting of the workpiece, positioning and other tightening action.
2.2 Operation control of welding system
The system is initialized and the status of each actuator is detected. Due to the different types of welding workpieces, different welding parameters are required. Control welding torch operation of the welding controller can store a variety of welding process parameters, each set of welding parameters corresponding to a welding process. The robot sends a welding reservation signal to the PLC. The PLC outputs the required welding parameters to the welding torch through the welding controller.
The system technology is that the work of safe and reliable, two welding stations exist independently, interactive operation. When the station 1 completes the welding of the type I purifier, the welding robot will automatically go to the left station 2 for the welding of the type II purifier according to the procedure. At the same time, the operator can carry out the loading and unloading of the workpiece in the station 1 and shorten the welding production Auxiliary time, increased productivity. The workpiece in the fixture positioning accurate and reliable, repeat the positioning of high precision, good welding quality. Each station of the welding fixture are used to drag the shifter, so that the welding process can change the workpiece welding attitude, with the robot's action, the quality and quantity to complete the welding of the purifier. The system's action is as follows:
Start → spot welding → vertical welding seam welding (at the same time station 2 folder workpiece, start) → above the end of welding, the shifter flip change → below the vertical weld welding → welding the end of the following; (Welding sequence is the same as station 1), spot welding and ring welding are completed on the station 1.
Press the station 1 to start the switch → the robot start the operation station 1 → press the station 2 switch, the station 1 action after the end of the station 2 program automatically run → remove the workpiece 1, put the new workpiece → press the station 2 switch → After the station 2 program is completed, the station 1 program runs automatically, and Figure 2 shows the relationship between the two stations.
According to the order of action for no-load operation, in the correct action after the clamping of the workpiece teaching, through the robot's teaching device to determine the welding process parameters of the station, the final test welding.
At present, the automobile manufacturing industry in the welding method to spot welding, arc welding. In the harsh welding conditions, as a set of mechanical, electronic, computer, control, sensors and other disciplines theory and technology in one of the welding robot, its working condition is stable, to ensure the quality of welding. The successful use of the workstations described in this article in the auto parts manufacturer fully demonstrates the versatility and flexibility of the workstation. As long as a slight adjustment of tooling and control procedures can meet the needs of different parts of the welding, and robot automatic welding cleaner size consistency, fixture positioning accuracy, sealing plays a vital role.