Can a CNC Router Cut Aluminum?

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Can a CNC router cut aluminum? This is one of the most asked questions; the answer to it is YES. Any CNC router is capable of cutting aluminum when it is done correctly. In this article, we shall be discussing this, and once you discover this secret, you will not only find cutting aluminum with a CNC router to be relatively easy but also very productive. With extra care and preparation, using a CNC router in cutting aluminum can be very efficient.

Tips for cutting aluminum using CNC router

1. Do not rush things

CNC can be used in cutting aluminum; however, it is not perfect for cutting out significant aerospace parts such as wing spars. The price you will have to pay for a successful cut is to slow the activity down. This does not mean you literally slowing down the speed as well as feeds, however, slowing down the overall material removal rates, which will become lesser than what you can attain when using a purpose-built CNC mill. Therefore, it is best if you relax and let your machine operate accordingly.

2. Using a feed and speed calculator

You should note that cutting aluminum with a CNC is not just a walk in the park, it is best if you do it right. You can benefit from using a feed and a speed calculator; nevertheless, you should take caution as you near the edge of the performance envelope. You should ensure that you have the appropriate feature for the CNC router. Some very essential features for CNC router that are available in a speed calculator include;

  • Minimum RPM setting. A speed calculator will be of no help if it always keeps telling you to go slower than you can possibly go.
  • The type of CNC router cutter. V-Bits, downcut bits, and compression bits are all essential for any CNC router user. You should always ensure that your new calculator can handle things accordingly.
  • Deflection. Tool deflection is accountable for various broken tools. Therefore, you should ensure that your calculator is capable of figuring out the deflection and has the ability to find solutions that helps in preventing excessive deflection.
  • Rubbing warning. Whenever you slow down feedrates excessively, then your cutter will quit slicing off some nice clean chips and begin plowing on the surface. This is known as rubbing, and it is responsible for reducing tool life because of the amount of heat being generated. It is best to get yourself a calculator that features rubbing warning.
  • Chip thinning. Whenever you take light cuts with a width that is less than half the diameter of your cutter, you will end up having chip thinning. Your calculator will have to compensate for that, or you will end up wearing out your tool prematurely.
  • The ability to derate horsepower for less rigid machines. It is best if your calculator features various machine profiles so that you can switch from full rating to derated profiles easily whenever you want to.

Once you have a calculator that will be able to handle the above aspects, your first issue, you will have to deal with will be the right RPMs becoming very low. Usually, the main issue with most CNC routers is that spindle moves faster when compared to various CNC mills. A typical new CNC mill has a maximum of 10,000 RPM, and most CNC routers cannot move that slow. Usually, life for most CNC begins at 20,000 RPM.

3. Using CNC router bits in cutting aluminum

CNC routers operate using various specialized cutters, which is not recommended for use with aluminum. Compression cutters, downcut spirals, and their likes are not ideal for cutting aluminum.

If you are looking for cutters that are ideal for cutting aluminum, 2 or 3 flute carbide endmills will be suitable for this project. These cutters will help you bump up the right RPM in which CNC spindles operate with. The measurement that is used in determining this process is known as Surface Speed. Carbide cutters are capable of moving at a higher speed when compared to HSS cutters. Therefore, you should not use HSS and Cobalt cutters when dealing with aluminum.

4. Using cutters with a much smaller diameter 

Another way in which you can bump up RPMs is by using a smaller diameter cutter. You should not use ½ inch endmills; however, drop it down to ¼ inch maximum and typically less. Since you will be going for a smaller diameter, it will be best to use a more rigid cutter for fear that tool deflection will start becoming a problem. It would help if you always remember to use a feed as well as a speed calculator that is ideal for tool deflection. Usually, carbide cutters are more rigid when compared to HSS, making it perfect for working with aluminum.

5. You should be paranoid on clearing chips

This is not something to stress much on, especially when the material has an affinity of bonding with a cutter. Recutting chips often destroys more cutters; therefore, you should always be paranoid when clearing the chip.

6. Lubricating using mist

Let’s assume you are paranoid about the chips, the best thing to do is to use lubricants in cutting down the tendency for chips sticking in a cutting edge. Most CNC router users are loathed messing with any coolant; however, you will have to use some lubricant in cutting anything.

7. Do not slow down feedrate excessively 

When you go slowly on the feedrate, you will be risking your tool rub instead of cutting. This is by far higher risk for a CNC router user than a mill user since the spindle features a much higher speed. To maintain the appropriate chip load with RPMs moving at high speed, you will have to keep your cutter moving smartly.

Final Thoughts

Cutting aluminum using a CNC router is doable with almost any router. It is all about matching your machine’s capability to the appropriate feed and speed required when dealing with metal and selecting the right tools and cutting parameters. This will be achieved by having the best feed and speed calculator. Furthermore, you should keep in mind the need for lubrication as well as being paranoid about the chips pilling up, and you should be ready to use a CNC router to cut aluminum.

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