laser welding aluminum problem

Points for attention in laser welding aluminum alloy
As one of the most common light metals in the industrial market, aluminum alloy has the advantages of high strength, corrosion resistance, and low density, and is widely used in the automotive, new energy, and aerospace industries.

Laser welding is one of the main methods of aluminum alloy processing at present. Compared with other welding methods, laser welding has the advantages of concentrated heating, small thermal damage, large weld depth-to-width ratio, and small welding deformation. At the same time, laser processing is easy to be automated, integrated, agile, and flexible, and can achieve fast and high-precision welding in a mass production environment, especially suitable for high-precision welding of complex structures.

However, due to the low boiling point, low laser absorption rate, high thermal conductivity, and high expansion coefficient of the aluminum alloy itself, various unpredictable problems will occur during laser processing, including pores, thermal cracks, etc. These problems will weaken the compactness of the weld, reduce the effective welding area, and reduce the welding quality. Therefore, during the processing of laser welding aluminum alloys, attention must be paid to whether there are errors in key links and key parameters.

Surface treatment before welding

If there are pollutants such as oil stains or dust on the surface of aluminum alloy materials, it will greatly affect the quality of laser processing. Therefore, if the storage environment is not clean, it is necessary to judge whether it is necessary to clean the surface of the raw materials.

The commonly used surface treatment methods include physical treatment and chemical treatment. The physical method will not be described in detail. The chemical method is mainly to clean with metal cleaning agent, and then wash and dry. If there is pollution that is difficult to remove, you can use it here. Add pickling or alkali washing in the process.

Correct welding process parameters

The main process parameters of laser welding include laser power, beam focal spot, material absorption value, welding speed, etc. Taking laser power as an example, there is an energy density threshold in laser welding. Only when this threshold is reached or exceeded, plasma will be generated, and laser welding can run smoothly and effectively.

Therefore, the correct welding process parameters are also very important for laser welding. The current laser welding is developing towards comprehensive intelligence, and its equipped motion control system can also effectively solve most problems, but it still needs to be carefully checked before use. , to avoid parameter errors.

laser welding aluminum problem

Protective gas

Shielding gas is directly related to welding quality and welding efficiency. Inert gas is generally used to protect the molten pool in aluminum alloy welding, such as argon, helium, etc. Argon gas is cheaper, denser, and has a good protective effect. The welding surface using argon gas will be smoother than helium gas; but argon gas will shield part of the beam and reduce the energy density, thereby affecting the effective power of laser welding. Helium is not easy to ionize and has the least impact on the beam. It is the most efficient shielding gas, but compared with argon and Helium, helium is more expensive.

In addition, it should be noted that the gas flow of the shielding gas is also one of the key factors. If the gas flow is too small, the plasma generated by welding will not be blown away, which will affect the stability of the molten pool; if the gas flow is too large, part of the shielding gas will be destroyed. Blow into the molten pool to generate air holes; only the appropriate air flow can reduce the generation of air holes and ensure the quality of laser welding

Laser Welding Machine for Aluminum

Laser beam welding is one of our most popular services for welding aluminum. The process is ideal for fast, clean welds. The heat affected zone is minimized and weld penetration can range up to 0.25” in aluminum.

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FAQ

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What wire does a laser welder use?

Select the welding wire according to the requirements of the workpiece, such as stainless steel welding wire for stainless steel workpieces, copper welding wire for copper workpieces, aluminum welding wire for aluminum and aluminum alloy workpieces, etc.

What gas is used with laser welding machine?

The shielding gas will provide favorable conditions for the formation of the weld. When the welded material has surface oxidation, it is necessary to use the shielding gas; when the welded material does not care about the surface oxidation, it is also possible not to use the shielding gas. There are three kinds of maintenance gases used most by laser welding machines, namely helium, argon and nitr

Advantages and disadvantages of Laser welding

10 common defects and solutions of laser welding.Show the problems and solutions

How thick of metal can a Laser Welder weld?

First, the welding thickness determines how much power should be used, that is to say, the thicker the workpiece to be welded, the more powerful the laser welding machine should be selected. 1. 1000W laser welding machine: the welding effect is good for plates with a thickness of less than 3mm. 2. 1500W laser welding machine: the welding effect is good for plates with a thickness of less than 5mm.

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Q What are the parameters for Fibre laser welding?

A Laser welding is one of the important aspects of the application of laser processing technology, and it is the most watched and most promising welding technology in the 21st century. Compared with traditional welding methods, laser welding has many advantages, such as higher welding quality and faster efficiency. At present, laser welding technology has been widely used in manufacturing, powder metallurgy, automobile industry, electronics industry, biomedicine and other fields. First, the principle of laser welding Laser welding belongs to fusion welding, using laser beam as the welding heat source. The welding principle is: the active medium is excited by a specific method to make it oscillate back and forth in the resonant cavity, and then converted into a beam of stimulated radiation. When the beam and the workpiece are in contact with each other , its energy is absorbed by the workpiece, and welding can be performed when the temperature reaches the melting point of the material. △Laser welding principle According to the formation mechanism of welding pool, laser welding has two basic welding mechanisms: heat conduction welding and deep penetration (small hole) welding. The heat generated during heat conduction welding diffuses to the inside of the workpiece through heat transfer, melting the surface of the weld seam, and basically does not produce vaporization. It is often used for welding low-speed thin-walled components. Deep penetration welding vaporizes the material and forms a large amount of plasma. Due to the high heat, small holes will appear at the front of the molten pool. Deep penetration welding can completely penetrate the workpiece, and the input energy is large and the welding speed is fast. It is currently the most widely used laser welding mode. Second, the main process parameters of laser welding There are many process parameters that affect the quality of laser welding, such as power density, laser pulse waveform, defocus, welding speed and auxiliary blowing shielding gas. 1. Laser power density Power density is one of the most critical parameters in laser processing. With a higher power density, the surface layer can be heated to the boiling point within microseconds, resulting in a large amount of vaporization. Therefore, high power density is very beneficial for material removal processes such as drilling, cutting, and engraving. For a lower power density, it takes several milliseconds for the surface temperature to reach the boiling point. Before the surface layer vaporizes, the bottom layer reaches the melting point, which is easy to form a good fusion weld. Therefore, in heat conduction laser welding, the power density is in the range of 104-106W/cm2. 2. Laser pulse waveform The laser pulse waveform is not only an important parameter to distinguish material removal from material melting, but also a key parameter to determine the volume and cost of processing equipment. When the high-intensity laser beam hits the surface of the material, 60-90% of the laser energy will be reflected and lost on the surface of the material, especially gold, silver, copper, aluminum, titanium and other materials with strong reflection and fast heat transfer. During a laser pulse signal, the reflectivity of the metal changes with time. When the surface temperature of the material rises to the melting point, the reflectance will drop rapidly, and when the surface is in a molten state, the reflectance stabilizes at a certain value. △Laser welding pulse waveform of different materials 3. Laser pulse width Pulse width is an important parameter for pulsed laser welding. The pulse width is determined by the penetration depth and the heat-affected zone. The longer the pulse width, the larger the heat-affected zone, and the penetration depth increases with the 1/2 power of the pulse width. However, increasing the pulse width will reduce the peak power, so increasing the pulse width is generally used for heat conduction welding, and the weld size formed is wide and shallow, especially suitable for lap welding of thin and thick plates. However, lower peak power results in excess heat input, and each material has an optimum pulse width that maximizes penetration. 4. Defocus amount Laser welding usually requires a certain amount of defocus, because the power density in the center of the spot at the laser focus is too high, and it is easy to evaporate into holes. On each plane away from the laser focus, the power density distribution is relatively uniform. There are two ways to defocus: Positive and negative defocus. If the focal plane is above the workpiece, it is positive defocus, otherwise it is negative defocus. According to the theory of geometric optics, when the distance between the positive and negative defocus planes and the welding plane is equal, the power density on the corresponding planes is approximately the same, but in fact the obtained molten pool shape is somewhat different. Wh

Q What materials can the handheld laser welding process weld?

Q What are the safety precautions for laser welding machine?

A Laser welding machines are generally used for tailor welding and repair welding of metal materials. The working principle of laser welding is to use high-energy laser pulses to heat a small area of the material. The high-temperature energy diffuses from the surface of the material to the inside, and forms a specific molten pool after melting. The material in the whole process is in a high temperature state, so how should we use the laser welding machine safely? Precautions for safe use of laser welding machine 1. During the operation, if there is an emergency, such as water leakage or abnormal sound of the laser, it is necessary to immediately press the emergency stop button and quickly cut off the power supply. 2. The external circulating water switch of laser welding must be turned on before operation. Since the laser system adopts water cooling mode and the laser power supply adopts air cooling mode, if the cooling system fails, it is strictly forbidden to start the machine. 3. It is strictly forbidden to touch all circuit components in the machine while working. When the laser welding machine is working, the circuit is in a state of high voltage and strong current. Untrained personnel are prohibited from operating the machine. 4. It is strictly forbidden to use the eyes to scan the laser directly when the laser is working, so as to avoid eye injury. It is forbidden to use external equipment to reflect the laser light when the laser light is working. 5. Do not disassemble any parts of the machine at will, and do not weld when the safety door of the machine is open, and do not aim the laser head at the equipment parts. 6. Do not place flammable and explosive materials in the laser light path or where the laser beam can be irradiated, so as not to cause fire and explosion.

Q What are the limitations of laser welding?

laser welding aluminum problem- Laser Welding Machine for Aluminum

laser welding aluminum problem