l'usinage par extrusion

Understanding the Aluminum Extrusion Process Aluminium extrusion machining is a process of manufacturing products with a cross-sectional profile by forcing the material through a die. This process can be likened to putting toothpaste in a tube, in this case, the toothpaste is the heated cylindrical aluminum bar also called an ingot and the tube is the die. Here’s a step-by-step breakdown: Heating and Pressing: The aluminum ingot is then heated and passed through the die which gives it the required profile of the product. Cooling: After the shaped material has come out of the die it is cooled by air or water. Stretching: Although not fully set, the profiles are pulled to relieve internal stresses and achieve the proper dimensions. Cutting and Aging: The profiles are cut and then aged – hot or cold to reach their final strength. Finishing and Surface Treatment: The last processes include polishing or other treatments meant to improve the looks and protect against corrosion. What is an Aluminum Extrusion Machining Center? An extrusion machining center is a specific type of machining center that is used to accurately process extruded aluminium profiles into the final required parts. Sawing, deburring, drilling, turning, milling, and tapping are some of the techniques used to give the required shape with features such as pockets and holes. At CNM, we have different types of extrusion machining centers that are highly accurate, fast, and very reliable. These machines are very efficient in cutting down production time and minimizing wastage during the processing of the products and are thus very suitable for use by manufacturers. CNM’s extrusion machining centers facilitate the manufacturing process and produce quality work that guarantees the aluminum extrusions are cut and profiled to the required specifications. Factors Consideration For Machining Aluminium and Aluminium Alloys The below-mentioned factors greatly influence the cnc extrusion machining of aluminum alloys. Cutting Force The cutting force needed when machining aluminum alloys is much less compared to the force needed when machining steel. For instance, the force required to machine aluminum is about one-third of that required for low-carbon steel thus chip removal is three times more efficient. For instance, aluminum alloy 2017A has the same cutting force as low-carbon steel but has similar mechanical properties as the latter. Tooling The cutting tools used in the machining of aluminium alloys must have a certain geometry. The cutting edges should be as sharp as possible and the tool faces must be smooth so that they can shed the swarf and not stick to it. The cutting angles are different according to the type of alloy, but the rake angle should be more than 6° and can be even 12°. In the case of alloys with up to 7% silicon content, it is suggested to use the tools with the application of TiN or TiCN coatings using PVD deposition. For diamond coated carbide tools and polycrystalline diamond (PCD) tools, the recommended rake angle is 15 degrees. It is much longer than the ones used for machining steel due to the proper tools being used in this process. In the special machines, the high-speed spindles can attain the machining speed of 2000 to 3000 m/min for the 2000 and 7000 series alloys. For instance, a 12 mm diameter tool can reach 50,000 rpm of cutting speed with a feed rate of 10 m/min, which results in very thin sheets and lightweight components. Cutting Speed and Feed Rate Because of the low modulus of elasticity of aluminium alloys, it is recommended to avoid high rates of advance even in roughing operations. The feed rate should be limited to 0. 3 mm per revolution. For finishing operations, the feed rate will be affected by the required surface finish. The depth of cut will be influenced by the level of accuracy that is needed on the final product. Lubrication Lubrication is crucial in machining aluminium alloys for several reasons: it reduces the temperature of the cutting area, keeps the swarf from sticking to the tools, and clears the swarf from the machining area. There are three primary types of lubrication: The three types of cutting fluids are spray mists, full cutting oil, and oil emulsions, of which the oil emulsions are most frequently used because of the heat dissipation of approximately 200 kg/J. Coolants help in reducing friction and also in tapping operations. Spray mists are not very effective when there is high heat involved. The cutting fluid composition should not react with aluminum alloys, cause stains or corrosion, contain anti-bacterial agents to discourage fungal growth, and be environmentally friendly. Benefits of Aluminum Extrusion Machining: The following are the benefits of machined aluminum extrusion: Aluminum extrusion is a process that is commonly practiced in the present generation due to the following benefits associated with aluminum extrusion. It also allows one to achieve complex and accurate forms of the needed shapes and also to produce them in a way that they will fit the intended use, thus increasing productivity and saving money. The outcome is strong and light structures that are suitable for industries that require light structures such as the aeronautics, automobile, and construction industries. Also, it is an efficient technique, which does not require a lot of material and energy and generates a small amount of waste. In conclusion, machined aluminum extrusion is cost-efficient and sustainable which improves the quality of the end product and production process. Suitability of Aluminum for Cold Extrusion Cold extrusion is a process of extruding aluminum through a mold at a temperature of not more than 150°C (300°F). The aluminum remains rigid and thin-walled parts can be fabricated as in the case of radiators, windows, and door frames. This process is slower than hot extrusion but the surface quality is high and the shapes are more accurate therefore less post-processing is required. Warm Aluminum Extrusion Warm extrusion is done at moderate temperatures while the rate of hot extrusion and the accuracy of cold extrusion are intermediate. The exact temperature is therefore arrived at