I. Key Points for Welding Aluminum Alloy Materials with Welding Robots
Welding challenges of aluminum alloy materials:
1. Aluminum alloys have a thermal conductivity 1 to 3 times higher than steel, making them prone to heating. However, this material is not resistant to high temperatures and has a large coefficient of thermal expansion, which easily leads to welding deformation. Moreover, this material is also prone to cracking and burn-through during welding, especially thin aluminum sheets, which are even more difficult to weld.
2. During the welding of aluminum alloys, a certain amount of hydrogen gas will be generated in the molten pool. If this gas is not discharged before the weld is formed, it will leave pores in the weld, affecting the quality of the welded parts.
3. Aluminum alloy welding also has problems such as joints being prone to softening and low surface tension in the molten state, which easily leads to defects.
Welding robots achieve stable welding of aluminum alloy materials:
1. Preparations before welding:
Before welding, the surface of the aluminum alloy must be cleaned, and all dust and oil must be removed. Acetone can be used to clean the surface of the aluminum alloy welding area. For thick aluminum alloy plates, first clean with a wire brush, and then clean with acetone.
2. Stable welding during the welding process:
During the welding process of aluminum alloys, the welding robot selects the dual-pulse function. The dual-pulse current is fixed and switches periodically between the peak current and the base current at the frequency of low-frequency pulses, so that the weld seam forms a regular fish scale pattern.
The welding wire material used should be as close as possible to the base material. Whether to choose aluminum-silicon welding wire or aluminum-magnesium welding wire depends on the requirements of the weld.
When the plate is thick, it is necessary to preheat the plate beforehand, otherwise incomplete welding may occur. When finishing the arc, a small current should be used to finish the arc and fill the crater.
3. Quality inspection is carried out after welding is completed:
Operators can visually inspect the filler content of the weld. A well-formed weld is characterized by a weld surface that is higher than the surface of the workpiece after welding, smooth and beautiful weld ripples, and no welding defects such as weld beads, cracks, weld burn-through, porosity, or spatter on the surface of the workpiece.
Weld flaw detection can perform penetration testing without damaging the weld. Various testing methods are available, and the appropriate method can be selected based on the material of the weldment and the specifications of the weld, thereby detecting the weld repair rate.
II. The Role of Welding Robots
1. The control system has input and output functions. Most welding robots use offline programming. Technicians pre-write welding programs and then input them into the control system. The control system intelligently identifies the weld specifications through sensors, selects appropriate welding parameters, and places suitable welding material to fill the weld, resulting in a beautiful and strong weld.
2. Weld point position control. The control system drives the actuator to make the robotic arm move along the welding path. After this series of actions is completed, it will automatically save the data through memory and can be recalled when welding the workpiece again. Weld point control improves welding accuracy and precision.
3. Intelligent welding material delivery. Traditional welding is done manually based on experience, resulting in inconsistent weld quality. The control system of the welding robot can automatically identify the weld specifications and deliver the exact amount of welding material to fill the weld according to the programmed parameters. This saves welding materials and reduces material costs for enterprises while ensuring the aesthetics of the weld.
4. Connection with auxiliary equipment. The control cabinet has multiple interfaces that can be connected to auxiliary equipment. The welding program can also be added to the auxiliary equipment's program, allowing the auxiliary equipment to work in conjunction with the welding robot. This improves the flexibility of automated welding, extends the welding path, greatly increases welding efficiency, and ensures consistent quality.
5. Controlling the coordinated movement of various mechanisms. The welding robot has input/output functions, allowing it to input programmed data and perform welding on workpieces through teach-and-playback. Coordinated movement of each axis can improve welding speed and stabilize welding quality. The welding robot can be considered a major part of the robot and is an important component of the welding robot.
