With the vigorous promotion and advocacy of production automation, industrial robots are being used more and more, especially in the welding industry. There are many benefits to using robots for welding, but robots are still machines, and there are many welding defects that still need to be resolved by humans. Today, let's talk about those welding defects.
Composition of welding robots
Welding robots are industrial robots that perform welding (including cutting and spraying). They mainly consist of two parts: the robot and the welding equipment.
The robot consists of the robot body and a control cabinet (hardware and software); while the welding equipment, taking arc welding and spot welding as examples, consists of a welding power source (including its control system), a wire feeder (for arc welding), and a welding torch (or clamp). For intelligent robots, a sensing system should also be provided, such as laser or camera sensors and their control devices. There are spot welding, servo, and arc welding robots.
Problems and solutions of welding robots
1. Welding misalignment: This may be due to incorrect welding position or problems when searching for the welding torch.
At this point, it's necessary to check the accuracy of the TCP (welding torch center point position) and adjust it accordingly. If this situation occurs frequently, check the zero position of each axis of the robot and recalibrate to correct it.
2. Undercut problem: This may be due to improper selection of welding parameters, incorrect welding torch angle or position. Adjustments can be made accordingly.
3. Porosity problem: This may be due to poor gas protection, excessively thick primer on the workpiece, or insufficiently dry protective gas. Adjustments can be made accordingly to resolve the issue.
4. Excessive spatter: This may be due to improper selection of welding parameters, gas composition issues, or excessively long welding wire extension. The welding parameters can be changed by adjusting the machine power, adjusting the gas ratio meter to adjust the mixed gas ratio, and adjusting the relative position of the welding torch and the workpiece.
5. Problem of an arc crater forming at the end of the weld after cooling: Add an arc crater function to the working step during programmable operation to fill the crater.
Common system failures during welding
1. Gun collision: This may be due to workpiece assembly deviation or inaccurate welding torch contact (TCP). Check the assembly or correct the welding torch TCP.
2. Arc failure occurs and arc cannot be ignited: This may be due to the welding wire not contacting the workpiece or the process parameters being too small. You can manually feed the wire, adjust the distance between the welding torch and the weld, or adjust the process parameters appropriately.
3. Protective gas monitoring alarm: There is a fault in the supply of cooling water or protective gas. Check the cooling water or protective gas pipeline.
Use in conjunction with the Hawker stress relief robot to eliminate welding stress.
Programming skills for welding robots
1. Select a reasonable welding sequence to reduce welding deformation and welding torch travel path length.
2. The spatial transition of the welding torch requires a short, smooth, and safe movement trajectory.
3. Optimize welding parameters. In order to obtain the best welding parameters, make working specimens for welding tests and process evaluation.
4. Employ appropriate positioner positioning, welding torch posture, and welding torch-to-joint position. After the workpiece is fixed on the positioner, if the weld seam is not in the ideal position and angle, the positioner must be continuously adjusted during programming to ensure that the weld seam gradually reaches a horizontal position according to the welding sequence. Simultaneously, the positions of each robot axis must be continuously adjusted to reasonably determine the position, angle, and wire extension length of the welding torch-to-joint. Once the workpiece position is determined, the position of the welding torch-to-joint must be observed visually by the programmer, which is quite challenging. This requires programmers to be adept at summarizing and accumulating experience.
5. Insert the torch cleaning program in a timely manner. After writing a welding program of a certain length, the torch cleaning program should be inserted in a timely manner. This can prevent welding spatter from clogging the welding nozzle and contact tip, ensure the cleanliness of the welding torch, improve the life of the nozzle, ensure reliable arc ignition, and reduce welding spatter.
6. Programming is generally not something that can be done in one step. It requires continuous testing and modification during the robot welding process, as well as adjustments to welding parameters and welding torch posture, to create a good program.
Operating costs and management of welding robots
Imported robot parts are expensive, so efforts should be made to reduce operating costs in all aspects. For lubricants, cheaper alternatives with similar performance and effectiveness can be found domestically. Strengthen maintenance during the welding process to extend the lifespan of consumable parts such as nozzles and contact tips. Furthermore, preventative maintenance of the robot system can effectively extend the lifespan of its components.
Highly qualified managers, technicians, and operators are essential for robots to achieve maximum efficiency. The effectiveness of a company's welding robot utilization largely depends on its workforce; therefore, maintaining a stable workforce is crucial.
