The Benefits of Using Magnesium for CNC Machining
Magnesium and its alloys are growing in popularity within the manufacturing sector. Here’s why.
Magnesium is the ninth most abundant element in the universe, the fourth most common element on Earth, and the third most commonly used structural metal (after iron and aluminum).
The material’s popularity in the manufacturing sector dates back to World War I, when it was used to build aviation components. In subsequent decades, magnesium became increasingly prevalent in the automotive, aerospace, and medical industries. In the last decade, its use has continued to grow in those industries, as well as in the technology sector in the building of laptop computers, televisions, cell phones, and countless other electronic devices.
Magnesium’s natural properties, along with the benefits it provides those using it, make it an attractive option for CNC machining.
The chief appeal of magnesium is its weight. Magnesium and its alloys are as light as plastic, but as tough as metal. When alloyed, magnesium’s strength-to-weight ratio exceeds all other structural metals. This gives the material a tensile strength on par with steel and aluminum, as well as a low density that’s helpful for reducing weight — and, in turn, increasing fuel efficiency — in automobiles.
Magnesium is also very easy to machine compared to other metals. Sawing, punching, drilling, milling, turning, and other processes are smoother when using magnesium, and machining the material requires a significantly lower cutting force and overall production time than other metals.
In addition, the short chips produced when machining magnesium will result in an excellent surface finish — a finish that isn’t impacted as much by the deep and quick cutting as it is the feed rate.
Magnesium’s unique and positive properties can produce some tangible benefits when it comes to CNC machining.
Not only do the short chips produced in the machining process have an excellent surface finish, but they also break evenly and consistently, making them easier and more accurate to work with than other metals.
Using magnesium also requires less power than other metals — roughly 55% lower than aluminum alloys, for example — and causes less wear and tear to cutting tools, thus prolonging their lifespan.
Perhaps most importantly, the savings realized by lower power consumption and prolonged tool life are compounded by the savings produced by magnesium’s high machining speeds and large feed rates, which reduce overall machining time, cut variable costs, and shrink your overall investment.
While magnesium’s lightness, strength, workability, and comparative affordability make it an attractive option for CNC machining, your team should follow a few best practices to ensure safe production.
While solid magnesium is difficult to ignite, magnesium powder, shavings, and chips — especially in ribbon form — are very flammable. Not only should your team avoid any open flames when working with magnesium, but they should also be diligent about cleaning out chip pans and avoiding mixing magnesium chips with any other chips.
If they can’t be recycled, chips should be kept dry at all times and stored in closed bins such as steel drums, separate from chips of other materials and away from flammable materials. If chips are wet, they should be stored in a remote location like an outdoor storage shed. While finished magnesium parts don’t need to be stored remotely, they should also be kept dry.
Your team should also keep tools in their proper condition, avoid tight clearance angles and water-based coolants, and use only an explosion-proof vacuum system for chip extraction.
It should also be noted that water will not extinguish fires involving magnesium, but rather make such a fire worse. As a result, in the event of a magnesium fire, your team will need to use a Class D fire extinguisher — designed specifically for metal fires — to extinguish it. A bucket of sand will work, as well.