Quelle est l'efficacité des machines de soudage au laser de l'aluminium ?
Sep 2, 2024
Aluminum can be a challenging material to weld. Contamination and porosity issues can arise as a result of oxidation issues. However, when properly cleaned and handled, aluminum welds well with a laser.
The Difficulties of Welding Aluminum has properties that make it more difficult to weld than other metals. Because of its relatively high thermal conductivity (approx. 209 W/m K) and low melting point (1,221°F/660.3°C), it can only be welded using fusion welding processes.
To melt the material in the intended weld region, the MIG, TIG, laser, and electron beam fusion welding methods provide tremendous heat in a small area. Because of aluminum’s excellent thermal conductivity, heat spreads throughout the work piece, potentially melting too much material or deforming the entire item, making this small heat-affected zone crucial.
The amount of heat applied, as well as the location to which it is applied, must be precisely controlled. Manual welding techniques like MIG and TIG depend on the operator’s competence and heat sinking to regulate these variables. Because aluminum does not change color as it gets closer to its melting point, welding procedures that depend on visual assessment of material preparation may be inaccurate. Automatic techniques, including Laser and Electron Beam, use computers to regulate feed rate, power, and weld placement, providing more accurate and reliable weld quality.
Aluminum Oxidation
Another difficulty in welding aluminum is the formation of an oxide film on the work surface. Aluminum oxide has a melting point that is approximately three times that of pure aluminum, which can result in particles of aluminum oxide contaminating the weld and causing porosity issues. Prior to welding, the oxide film must usually be removed mechanically or chemically. Aluminum oxide can interfere with laser welding because it changes the reflectivity of the part’s surface, reducing the amount of laser energy that reaches the base metal.
Hydrocarbon Contamination
Hydrocarbon contamination of aluminum during storage and preparation can cause welding issues. Prior to welding, aluminum parts are frequently formed, sheared, sawed, and machined. If a lubricant is used during any of these pre-weld operations, it must be completely removed prior to welding to avoid bad welds. Prudence dictates that aluminum parts that are to be welded be pre-weld processed in such a way that minimal to no lubricants are used — sawing and machining of aluminum should be done dry, if possible, and thoroughly cleaned if not.
Aluminum Laser Welding Laser beam welding is one of our most popular aluminum welding services. This process works well for making fast, neat welds. There is a smaller heat-affected zone and up to 0.25′′ of weld penetration in aluminum. Laser beam welding can be applied to materials that are prone to cracking, such the 6000 series of aluminum alloys, provided that it is paired with a suitable filler material, like 4032 or 4047 aluminum. There are several types of lasers that work well with aluminum, and using a cover gas is often recommended.
Pre-Weld Preparation
The amount of pre-weld preparation required is largely determined by the condition of the aluminum parts to be welded, which is generally determined by storage conditions and the cleanliness of the machine procedures used to produce the part thus far.
Aluminum that will be laser welded must be thoroughly cleaned to avoid oxide films and hydrocarbon contamination. To remove any oxides, this is frequently accomplished mechanically by using stainless steel wire brushes, grinding, filing, or scraping. Chemical cleaning methods that use immersions in caustic solutions and water, on the other hand, are effective at removing aluminum oxide.
In general, acetone or alcohol-based solvents can be used to remove hydrocarbon residue from aluminum parts. When heated, chlorinated solvents can produce toxic gases, so avoid using them in the welding area. Before abrading the surface to remove aluminum oxide, hydrocarbon contamination must be removed.
Laser Welding Modes of Operation
There are several ways to apply laser beam energy to the work piece: as a continuous beam, as a sequence of pulses, or as a laser stir weld. The application, the material’s qualities, and other factors influence the process selected.
Pulsed Laser Welding
A pulsed laser is exactly that: the beam is switched on and off at a very high rate (10-1000 hz), resulting in a series of separate bursts of energy being applied to the work piece. Each pulse melts a small area of the work piece, which is then moved slightly and another pulse is applied, resulting in a series of overlapping welds that form a continuous bead.
Because each pulse-created weld patch cools quickly, the heat in the surrounding material is reduced, limiting the part’s maximum temperature and minimizing melting and distortion. When minimal heat input is needed, a pulsed laser works best for laser welding aluminum because of its high thermal conductivity.
Continuous Wave Laser Welding
Continuous wave laser welding, also known as keyhole welding, is used for deep penetration welds. The work item is moved underneath a steady laser light beam that is aimed at it. The material on the leading edge of the laser beam melts while the trailing edge cools. Continuous wave lasers normally feed at speeds between 25 and 100 inches per minute in order to prevent scorching the parts. Because heat is applied continuously rather than the item being constantly heated and cooled by a pulsed laser, continuous wave welding may be a preferable option for some of the more delicate aluminum alloys.
Superstar, l'un des principaux laser welding machine supplier, offers state-of-the-art solutions for various industries, including the aluminum machine à souder au laser. Our Aluminium laser welding machine are designed to deliver precise and reliable results, making them the ideal choice for welding aluminum and other materials with high efficiency and minimal distortion.