Views: 1 Author: hu Publish Time: 2021-09-22 Origin: dapeng
With the rapid development of industries such as the automotive, military, and heavy industries, the cutting of three-dimensional sheet metal parts and special profiles in these industries is showing a trend of small batches, diversification, and high precision. The robotic laser cutting system composed of industrial robots and fiber lasers, on the one hand, has the characteristics of industrial robots, which can freely and flexibly realize various complex three-dimensional curve processing trajectories. On the other hand, it adopts flexible and long-distance laser fiber as transmission. The medium does not restrict the movement path of the robot. Compared with traditional processing methods, the robotic laser cutting system can improve the flexibility of the entire laser cutting system while meeting the accuracy requirements, occupying less space, and having higher economy and competitiveness.
1. Robot laser cutting system related technology
Different from the motion control of spot welding and handling, laser cutting is based on the motion control under the continuous process. In addition to requiring the robot to have high precision of the movement point and repeat positioning accuracy, it also controls the trajectory of the robot movement, which is the robot. The accuracy of the linear and arc trajectory interpolation of this system puts forward very high requirements. The accuracy and stability of chamfer cutting and small circle cutting in laser cutting can be a good measure of the robot's motion control ability. ABB uses its strong R&D capabilities to develop a series of high-end technologies to meet the needs of the market. The developed TrueMove and QuickMove technologies can well solve the accuracy problem of chamfer cutting at high speed, while AdvancedShapeTuning and WristMove technologies can well solve the accuracy problem of small circle cutting.
1, TrueMove and QuickMove technology
As shown in Figure 1, the actual path of the traditional robot matches the programmed path at low speed, but when turning at high speed, the actual path will deviate from the programmed path. TrueMove based on advanced feedforward servo control technology greatly improves the accuracy of motion control, solves the problem that the actual motion path of the robot deviates from the programmed path at high speed, and truly realizes what is compiled is what you get.
As shown in Figure 2, the acceleration of the traditional robot remains unchanged during the speed increase and decrease, and the time to complete an action cycle is correspondingly longer. QuickMove based on advanced dynamic model control technology can accurately control the robot's acceleration, deceleration and stable speed, and reduce the motion cycle time by maximizing the robot's acceleration at any time.
2. AdvancedShapeTuning and WristMove technology
The AdvancedShapeTuning software developed by ABB can compensate the robot axis friction function, and make timely and accurate compensation for the small jitter and resonance of the robot when the robot is walking the complex three-dimensional cutting path. These functions are included in the options of the robot. During the application, the customer only needs to call the corresponding function module, and the robot can repeat the programmed path according to the instruction and automatically obtain the friction parameters of each axis.
WristMove is to make the robot do not move 1, 2, and 3 axes during cutting, and only the 4, 5, and 6 axes of the robot's movement end can move. This avoids the axis friction caused by the small circle cutting path when the 1, 2, and 3 axes are moving. The adverse effects.
3, offline programming simulation and human-computer interaction interface
RobotStudio is an offline programming and simulation software developed by ABB, which can complete almost all robot programming and simulation on a computer. As shown in Figure 3, a very realistic simulation can be achieved through RobotStudio, and all the robot programs and configuration files used are actually used. With the ABB AbsoluteAccuracy correction system, the simulation results can reach high accuracy. RobotStudio can also easily import mainstream CAD format data such as IGES, STEP, CATIA, and then compile robot programs based on these accurate data. Using the AutoPath function in the software, the robot position (path) required to track the processing curve can be automatically generated in only a few minutes, which solves the problem that the complicated cutting curve cannot be taught through teaching in laser cutting, and greatly saves Programming time.
The robot adopts the touch screen type teaching pendant FlexPendent, with the joystick and simple button design on the teaching pendant, it is very convenient to use. At the same time, ABB's newly developed special cutting operation software has a good laser cutting man-machine interface, which displays the cutting parameter setting, shaft friction adjustment and I/O monitoring interfaces on the teach pendant in the form of graphics and digitization. Very friendly, it is convenient for users to monitor and operate the system status.
2. Application cases related to robot laser cutting system
The laser cutting system constructed by the ABB2600 robot well embodies the robot's related technology in the laser cutting application field.
1. System composition of robot laser cutting system
The external layout and internal layout of the robot laser cutting system are shown in Figure 4 and Figure 5, respectively. The whole system is mainly composed of ABBIRB2600 robot and MTC750 turntable (Figure 6a), IPG laser and water cooling equipment (Figure 6b), Precitec laser cutting head (Figure 6c), and RIP smoke purification equipment (Figure 6d).
1) The IRB2600 robot has the highest positioning accuracy and acceleration in its class, which can ensure high output and low scrap rate to increase productivity. The cut sheet metal parts are placed on the MTC750 turntable. Using the MultiMove function of the ABB robot, the robot and the turntable can move in coordination, and can achieve high motion accuracy, thereby ensuring the laser cutting accuracy of the workpiece.
2) The laser generator and water cooling equipment are made by IPG, the model is YLS-1000, and the maximum laser power is 1000W. The laser is transmitted by optical fiber and used as a cutting heat source after being focused to quickly melt the material at the irradiated part. At the same time, the high-speed airflow coaxial with the laser beam is used to blow away the molten material to form a cavity. The beam and the material follow a certain track Make relative movement, so that the hole continuously forms a slit of a certain shape, and completes the laser cutting of the workpiece.
3) The laser cutting head adopts the YRC type cutting head from Precitec. In addition to the focusing lens used to focus the laser, the corresponding optical fiber socket, water cooling and gas connection port, the cutting head also has a height sensor, which is capable of anti-collision protection and automatic floating focusing. This function can effectively improve the quality of laser cutting.
In addition, in order to prevent the laser radiation and smoke pollution generated during the laser cutting process, the 2600 robot and the MTC750 turntable are placed in the working room. The entire processing process is carried out in the working room to observe the cutting process and loading and unloading. The windows are all made of special laser protective glass, and the smoke and dust generated are removed in time by the RIP purification equipment during the processing process, thus ensuring the safety of the entire laser cutting system.
2, system features
1) The use of ABB offline programming and simulation technology significantly shortens the programming and debugging time of the entire system and improves the overall production efficiency. Most robot programming can be done in RobotStudio environment. First, import the relevant robot, turntable model, Precitec laser cutting head, and the 3D model of the processed workpiece into RobotStudio, and use the AutoPath function to automatically generate a programming path according to the shape model of the workpiece, and perform path optimization and collision detection if necessary. Then through the virtual running of the robot program, the robot's motion path can be visually observed in the RobotStudio virtual three-dimensional environment for modification and adjustment. Finally, download the determined robot program to the actual robot controller, and perform a small amount of actual debugging to complete the robot programming of the entire system. The application of this technology in actual production, whether it is production or line change, robot programming can be prepared in advance, greatly reducing the time for debugging at the production site and stopping production, improving production efficiency, and expanding the return on investment of the robot system.
2) Adopt ABB robot TrueMove and QuickMove technology to ensure the robot's motion accuracy and speed to the greatest extent. At the same time, AdvancedShapeTuning is used to compensate the friction of the 6 axes of the 2600 robot, which improves the robot's own motion accuracy and minimizes the adverse effects of robot motion errors on the quality of laser cutting.
3) In addition to the high-quality laser cutting effect, the robot itself should have a high trajectory accuracy, and a good cutting process is also an indispensable factor. The cutting process involves the comprehensive adjustment of multiple factors such as cutting speed and acceleration, laser power, focus position, and air blowing volume. Figure 7 shows the small circles cut after process adjustment. The diameters are Φ6, Φ8, Φ10, Φ12, Φ14, Φ16, Φ20, Φ30. It can be seen that the thermal deformation of the cut circles is small, the edges are smooth, and there are no obvious defects. .
3. Conclusion
The robot laser cutting system not only has the characteristics of flexible robot movement and high flexibility, but also has the advantages of laser cutting, such as fast cutting speed, good quality, and narrow cutting seam. It satisfies the requirements of the development of modern manufacturing. At the same time, the robot is used in laser Related technologies in the cutting field can not only technically meet the requirements of complex three-dimensional cutting, but also help improve the quality of industrial products, while reducing production costs, which can bring huge economic benefits to enterprises.