5 ways to fabricate aluminum partsadmin
What are the 5 ways to fabricate aluminum parts ?
Aluminum is a widely used material to produce mechanical parts. Because it is an easy to process, its light and it is a strong material. In addition, there are different methods to apply a surface finish to protect aluminum from corroding and to give it a beautiful look.
Because aluminum is used in a broad range of applications, there are 5 different ways to fabricate aluminum parts.
1. Machining a full block or bar
This is the most straight forward ways of processing aluminum. A block of aluminum is mounted to a milling machine. Or, a bar is processed with a turning machine. The principle of both ways is to cut chips of metal with a cutting tool in order to obtain the desired shape of the product. In case of a milling machine, the cutting tool is rotating. Where as with a turning machine it is the product that rotates. Machining of aluminum parts allows fast cutting speeds. When there is good liquid cooling, the surface of the part will be nice. However, there will often be a difference in surface roughness depending on the feed direction compared to the rotation direction of the tool. Did you know that alcohol is a very good cooling agent to cut aluminum ? It makes the processed surface shiny.
The advantage is that almost any shape can be machined. However, we need to turn and clamp the part to process each surface. Unless we use a 5-axis CNC machine. And there is a lot of wasted material, which has an impact on the unit cost.
2. Aluminum extrusion
Extrusion is a process to make half fabricates. A bar of aluminum is heated to the deforming temperature. A piece of about 500 millimeter is cut of. This piece is put into the feeder of the extrusion machine. Next, the aluminum is pressed with high force through an extrusion mold, made of hardened steel. The result is a long piece of aluminum with the desired section of the product. Those pieces are usually 12 meters long. After extrusion, the strips are pulled to make the straight.
Now, the long pieces are cut to the desired length of the final product. In most cases the product still needs to be machined.
The advantage of extruded aluminum products is that there is a large reduction of wasted material in order to obtain the final part. However, the section of the product is fixed and the number of integrated features is limited.
Sheetmetal processing is a different way of 5 ways to fabricate aluminum parts. We start from a thin sheet of aluminum. Next the aluminum must be cut into the correct shape. Cutting of aluminum is done with a laser cutting machine, with a punching machine or with a press. There are flat sheetmetal parts and bended products. Bending of the aluminum sheets happens with a bending machine but also with punching machines and presses.
4. Molding and casting
There are different ways of molding aluminum parts. We can do injection molding where liquid aluminum is injected under high pressure into an injection mold. The result is a part with almost all desired features present after it comes out of the mold. This technique is suitable for production large quantities, because the injection mold is relatively expensive. The mold cost is a lot cheaper with sand casting but you have to accept the rougher shape and surface of the produce. There are bigger tolerances and the material is more brittle because of the casting under low pressure. In most cases the casted aluminum parts still need machining of certain features. Cavities with narrow tolerances are machined by CNC. Threaded holes are drilled and tapped after molding. Casted aluminum parts are not suitable for anodizing. Therefore they are usually powder coated.
5. Aluminum forging
Forging of aluminum parts is another way to reduce scrap material. We literally press a block of material between a positive and negative side of a hard steel mold. We us a large press with a pressure of 5 tons. The result is an perfectly shaped part. Just like with the other molding process, we machine burrs, holes and threaded holes afterwards to obtain a more accurate product. Aluminum products processed with a press are suitable for anodizing because the material structure is similar to extruded aluminum.
This manufacturing process for aluminum parts starts to be viable at production runs above 3000 pieces.
I hope you learned a bit more about the 5 ways to fabricate aluminum parts.