Yes, a CNC can cut through steel. However, if you have a little idea about CNC, then you already know that the above question is itself an amalgamation of a couple of other questions. How?
When we talk about CNC (Computerized Numeric Controller), then it can be either a CNC mill or a CNC router. In fact, both have a wide difference between them. Having said that, steel can be of multiple types, like stainless steel, mild steel, or so. Each of these require different CNC machines(maybe router or mill) to cut through.
We will discuss all the possible cutting processes to cut steel using a CNC machine. Plus, we will also answer some FAQs that may help you achieve the best and simplest steel cutting results.
CNC Laser Cutting Technique
This technique is ideally suited for Cutting a range of materials, primarily including stainless steel, mild steel, and other sorts of metal alloys. It is a sheet steel manufacturing procedure conducted by CNC laser cutters. The machine primarily follows a "vaporization cutting" technique where the laser ray melts the steel surface, while a high pressure gas separates the molten steel.
CNC Laser cutters are basically of three types:
1. Moving material: Its function is akin to conventional punch presses in which the laser beam is in a stationary position with the metal material moving along the X and Y axes beneath.
2. Flying optic: It features a fixed cutting bed for the material to be cut with the laser ray moving along X and Y axes above.
3. Hybrid laser cutters: It generally moves the cutting material along a single axis; X, while the optical head moves perpendicularly along the Y axis.
- The cutting range for CNC laser cutters lies between 0.3 mm to 25 mm for the CNC models with higher power.
- Laser cutting method uses different types of gases like oxygen, nitrogen, and compressed air to ease the steel cutting procedure.
If you are looking for precise and intricate cutting works on steel material, then laser based steel cutting technique should be your first preference.
CNC Router Cutting Technique
As mentioned earlier, both CNC router and CNC mill have a wider difference in terms of the types of materials they cut. While CNC routers are programmed to make projects that require intricate, precise, and repeated cuts on the materials including low elevation or flat wood or plastic, CNC mills are used to transform steel blocks to varied engine parts, components, and other creative metal pieces.
However, you can still have your CNC router work like a CNC mill but for cutting mild steel only. You just need to select the right router bits and cutters (with smaller diameters) to achieve precision cutting.
Note: According to the CNC experts, it is better to avoid using a CNC router for cutting stainless steel. This is because the cutting action on such a ferrous and high chromium-content material might produce high sparks unless a liquid is used to cool down the cutting process.
CNC Plasma Cutting Technique
This sort of steel cutting is a fast and cost-effective technique, typically utilized to cut stainless steel with absolute ease. The modern plasma cutting systems give you an extensive array of amperages and gases to generate a favorable cutting speed and get a desired quality of cutting result, as per the requirement.
Note: CNC Plasma Cutting is the best and most appropriate of all the three methods in terms of cutting stainless steel. So, I have answered some FAQs regarding plasma based steel cutting further below. Check out those to get more details if you wish to move ahead with this steel cutting technique.
Yes, absolutely. CNC Plasma is the most effective technique of cutting stainless steel of almost any thickness. But, the type of plasma source and stainless steel cutting table you choose can make a wide difference.
The cut quality of the CNC plasma cutter is significantly influenced by the machine's build quality in the long run. Typically, the cutting angles and edge quality (ripples vs no ripples) may be affected by the mechanical defects of the cutting table.
You must check the gantry stiffness (Y-axis which moves over the steel surface to be cut), also assess if the rail construction can be impacted by the heat produced during the cutting process.
Note: Though the steel cutting quality will remain the same when the CNC machines are still new, the heat dissipated every time while cutting might bend the metal build of the table over time, affecting the straightness of the plasma cutter.
Talking about the source of plasma, the primary difference between an industrial type and a low-cost air plasma system is the type of gas and pressure applied at which plasma gas will be emitted from the torch to conduct the cutting process. These two factors greatly impact the end-result of steel cutting.
This system only uses air to cut through stainless steel. Low-cost CNC air plasma system is fit for cutting a steel material of 25 mm width.
Since 78% of Nitrogen and 21% of Oxygen are two gases abundantly available in the atmosphere, the first gas is responsible for giving a black finish, while the second one raises a burning tendency. Consequently, the end result may not be as per the expectation, especially on thicker steel.
Overall, if you are looking for a decent steel cutting result, that too at an affordable price, then low-cost air CNC system is the best.
Industrial CNC plasma cutting system
This type of plasma cutter utilizes a couple of gas combinations for cutting stainless steel. This mechanism is mostly found in the latest industrial CNC plasma cutting models and is equipped to smoothly cut through sharp edges leaving behind a shiny texture. Systems like the Kjellberg HiFocus 600i Neo or HyPerformance® HPR800XD® are capable of cutting through a steel sheet of around 160 mm width.
However, apart from gas combinations, there is one more factor you must consider before using an industrial CNC plasma cutter that includes the output currents. Both these factors impact the achievable cut speeds and cut edge results.
For instance, Nitrogen based plasma helps cut the steel faster than usual but may produce a top-edged round, whereas using Oxygen in the system results in oxidation of the steel on the surface of its cut which needs cleaning. Well, this is just a secondary operation which you may avoid to save time.
Conversely, if you use a non-oxidizing plasma gas like argon-hydrogen (H35), then cutting gets slower but it produces chrome-like bright edges which do not need an added preparation before welding. Using Hydrogen based gases like F5, too, may produce sharper cut edges.
Industrial CNC plasma sources like Hypertherm’s X-Definition™ XPR300™ plasma cutting system is one of the most recent types of its kind that allows using mixed gases to conduct cutting. This way, you can achieve a blend of high cut quality derived from argon-hydrogen, and cut-speeds of Nitrogen and air.
Whether you use a me handled CNC plasma cutter or an air CNC plasma system, either way, you will get clean cutting of stainless steel. But, the latter CNC plasma type leaves a rougher cut on the steel surface compared to the former.
While choosing and trying to settle for a CNC plasma machine to cut stainless steel, first try to prioritize your requirements and purpose. In some cases, productivity is the sole utility of using this CNC machine. Whereas, edge quality is another most crucial factor to count on.
Next, decide a budget that you will stick to while buying a CNC plasma cutter model. Affordable air plasma options are readily available on the market. The only setback is that you may have to compromise with the cut and speed quality that a higher quality precision plasma cutter can provide.
Using a CNC plasma cutter for slicing stainless steel is not only favorable but also the best solution to get swift and consistent delivery of brilliant cutting results.
We hope the above information has helped you understand more about the various types of steel and also the methods used to cut through them using different types of CNC.