Aluminum is one of the most popular materials for CNC machined parts - here are six reasons why.
If you ask any CNC precision machine shop about machining aluminum, they will point out its simplicity. Aluminum is very dimensionally stable, so you can cut away a lot of it and still keep the residual stress within limits. Using carbide tools and modern coolants will give you an excellent finish. For a matte finish, you can bead blast the parts or anodizing them for a uniform aesthetic finish and added corrosion resistance.
Most importantly, this machinability helps keep the cost of your part down. However, you choose a material based on the properties you need for your part, so what else does aluminum have to offer?
Aluminum is lighter than most metals. So if you're looking to save weight, it's a great choice. While pure aluminum has a tensile strength of less than 100 Mpa, it can be hardened as follows:
* Alloying, mixing with other elements, improves the grain structure.
* Heat treatment, heating and then cooling within a certain time to produce crystals of ideal size.
* Work hardening, where the metal is intentionally deformed to change its grain structure. This is usually done during heat treatment (e.g., rolling), but can also be done after the fact (during forging).
A "temper" designation indicates the exact condition or strength of the resulting material, H for "hardened" and T for "thermal."
It is worth noting that most aluminum alloys have a higher strength-to-weight ratio or specific strength than 316L stainless steel.
While titanium clearly emerges as the winner from the table below, when stiffness and weight savings are important, the high-strength aluminum alloys are a great cost-effective alternative when budget is a concern.
Since aluminum is a good base material to work with, there are a variety of alloys with different properties and uses to meet your needs.
These are divided into nine different series, with each series numbered as a thousand, so 6000 series for example, which is then further subdivided by a number. Generally, the closer the aluminum grade number is to another, the more similar they are, so 5082 and 5083 are almost identical.
Here are some of the most popular grades:
* 2024 - Aerospace grade with high fatigue strength. Alloying with copper trades off tensile strength (UTS) for more ductility/toughness.
* 5083 - Marine grade, with good corrosion resistance due to higher magnesium content.
* 6082 - Universal use and aerospace grade. A good mix of strength, ductility and corrosion resistance conditions high versatility and widespread use. This is achieved by alloying with a mixture of magnesium and silicon (also roughly equivalent to 6061 grade).
* 7075 - High strength aerospace grade, well balanced properties, especially under high static loads. It can be heat treated and contains more zinc, as well as magnesium and chromium.
Corrosion resistance varies by grade, but aluminum is an excellent choice if that's what you expect from your material. The metal and its alloys have an ideal affinity for oxygen - metals that are too reactive, such as magnesium, oxidize easily, while less reactive metals form a loose oxide film, such as rust on iron and steel.
In contrast, aluminum, when exposed, forms a passivating layer of aluminum oxide that seals the surface and prevents further oxidation and erosion. This layer is "self-healing" even when scratched, so the material does not need to be painted or surface treated. This means a cost savings in manufacturing and life cycle costs. You can enhance this natural corrosion resistance by anodizing - but more on that later.
While copper is often the material of choice when it comes to conductivity, aluminum is often used for electrical components because it is much cheaper and lighter. In fact, it's often used for bus bars, battery cables and connectors, especially in the automotive industry and electric vehicles.
Its good thermal conductivity also means that it is often used for heat sinks and heat dissipation.
With sustainability high on most people's agendas, it's good news that an estimated 75% of all aluminum produced remains in circulation. Recycling aluminum uses much less energy than producing it, and as long as we can keep contaminants under control, it can be used again and again.
It's already been mentioned that you can get a great finish by machining this material, and that aluminum is naturally corrosion resistant. For even better aesthetics, you can even have it anodized in different colors.
This is a surface finishing process that not only increases the wear and corrosion resistance of a material, but also makes it easier to color. At Richconn, we offer both decorative anodizing (Type II) and Type III, in which an even thicker layer of 50µm provides additional protection.
The process increases the thickness of the passivating oxidized layer through the use of acids as well as an electrolytic process.
The choice of material for your part is critical and is based on what properties you want the part to have. Aluminum is often a good choice for the reasons mentioned above, but there are many other metal and plastic options. To help you make the right choice for custom cnc machining, we've created a pocket-sized CNC material selector to serve as a quick reference guide.
If you have any questions about our services at Richconn, please contact an applications engineer at email@example.com or +86-0755-28025755. Have a finished design for custom 3D printing? Upload it now to get a quote.