November 18, 2022 15 min read

The last few years have seen a rising interest in CNC routers and CNC mills. Many people want to know if you can use a CNC router for aluminum processing. The simple answer is yes, but as with most things, there’s far more that you need to know.

In this article, we’ll take a closer look at the various aspects of using a CNC router for aluminum including:

  • When can you use a CNC router to cut aluminum?
  • How to cut aluminum with a CNC router
  • The different alloys of aluminum, and how to cut them
  • Differences between cutting aluminum sheets and aluminum plate
  • Tips and tricks for cutting aluminum with optimal efficiency

We’ll also take a detailed look at which tools and bits you should be using when cutting aluminum with a CNC router. Not all bits are equal, and buying the right ones can mean the difference between success and failure. Let’s get into it.

Can You Cut Aluminum with a CNC Router?

Yes, you can use a CNC router for aluminum processing. However, it offers a set of challenges and considerations that are usually absent when processing wood or plastic.

For instance, bits and tools are more likely to slip or rub over aluminum instead of cutting as you want them to. You also have to pay special attention to the debris created by the routing process.

Buildups of debris in the toolpath can lead to warping, bending, or even breaking the workpiece or cutting tool. We’ll investigate the various considerations in detail in the following sections.

How to Cut Aluminum with a CNC Router

Now that you know you can use a CNC router for aluminum, let’s take a closer look at precisely how to accomplish this somewhat finicky task.

While the low melting point and high malleability of aluminum mean that there are special considerations when routing aluminum, the basic process remains the same.

In short, the process consists of:

  1. Creating or downloading a design for the item you wish to produce, using Computer-Aided Design (CAD) software.
  2. Programming the type of workpiece, cutting tools, toolpaths, and other manufacturing aspects using Computer-Aided Manufacturing (CAM) software.
  3. Aligning the workpiece on the worktable and attaching it for a smooth cutting experience.
  4. Using a G-code sender and a control software program to control the machine and apply the programming functions you’ve already created.
  5. Cleaning up the workpiece and doing any finishing work that your project may require.

Using your CNC routers for aluminum mainly differs in the manufacturing stage. The bits you choose, the speeds you use, and other elements can play a significant role in the end result.
We’ll take a closer look at these elements in the section labeled ‘Tips for Cutting Aluminum Effectively’.

Aluminum Vs. Aluminum Alloys

In its pure state, aluminum is a highly malleable metal with an incredibly low melting point when compared to other metals. However, very rarely will a CNC machinist have the opportunity to work with aluminum in its pure form.

This is mainly because pure aluminum is considered ductile (able to be worked into thin wire without the addition of other materials). In layman’s terms, this metal is much too soft and bendable to be useful in its pure form.

Instead, most of the aluminum-based materials that you work with will probably be alloys of two different metals, with aluminum being the main component. The grade, or quality, of the alloy produced, depends on the type of metal added to the aluminum. Different grades of alloy are useful for different types of projects. Let’s take a closer look at some of the different alloy types.

One of the main differences between the aluminum alloys is that some get heat treated while others don’t:

  • Heat-treated alloys - Manufacturers produce these alloys at particularly high temperatures of up to 1,050 degrees Fahrenheit. These high temperatures allow both metals to achieve their optimal melting point, causing them to blend more completely. Heat treatment also increases the alloy’s strength and durability.
  • Non-heat treatable alloys - Instead of melting the metals to combine them, these alloys combine the metals through a purely physical process. Often, the metals get rolled or stretched to incorporate them into one another. During the process, area reduction occurs to stabilize the alloy.

Now that you understand the differences between the two types of manufacturing aluminum alloys, let’s look at some of the different alloys:

  • Aluminum MIC-6 - A heat-treatable alloy that’s primarily blended with zinc. This alloy is primarily used in the production of plate aluminum. It’s ideal for tools and projects which require a high degree of accuracy. This alloy isn’t good for welding projects.
  • Aluminum 2024 - A heat-treatable alloy that’s primarily blended with copper. This is considered a medium-high strength alloy and has a fantastic strength-to-weight ratio.
  • Aluminum 3003 - A non-heat treatable alloy that can be cold-wrought to produce various elements. It’s highly resistant to rust, and the main alloying component is manganese.
  • Aluminum 5052 - A non-heat treatable alloy primarily alloyed with a combination of manganese and chromium. It’s moderately strong and sports a high resistance to rust and fatigue. It also works well for welding applications, and doesn’t have the same tendency to crack and fracture as MIC-6.
  • Aluminum 5083 - A non-heat treatable alloy that’s highly resistant to corrosion, and the degrading qualities of seawater. It works moderately well for welding applications, but manufacturers don’t recommend using it in applications that attain temperatures of over 149 degrees Fahrenheit.
  • Aluminum 6061 - A heat-treatable alloy that’s primarily blended with magnesium and silicon. An excellent alloy for various functions but not recommended for high-stress applications. It has a fantastic strength-to-weight ratio and is naturally resistant to rust, making it ideal for applications where less than ideal conditions may be encountered.
  • Aluminum 6082 - A heat-treatable alloy that’s commonly used (in plate form) for machining. It’s a medium-strength metal (and the strongest of the 6,000 series alloys), with high rust resistance. Magnesium and silicon are the primary blending elements used in this alloy.
  • Aluminum 7075 - A heat-treatable alloy using zinc as the primary element for alloying. It’s tough, has high strength and resistance to fatigue, and it’s also extremely ductile. It has excellent mechanical properties and is often used for machining.

Of course, there are many other alloys as well. We’ve only looked at a few of the most commonly used alloys.

Sheet Aluminum Vs. Aluminum Plate

If you’re milling aluminum with a router, it’s essential to understand the differences between sheet aluminum and aluminum plate.

The primary difference between the sheets and the plates is the thickness of the product. Aluminum sheets have thicknesses of under .249”, while aluminum plate has thicknesses of .250” or more.

Sheets and plates are also generally used for different applications:

  • Sheets - The most common way to buy aluminum, and therefore the most regularly used. Sheet aluminum often finds use in creating tins, and other types of aluminum packaging. Other uses include the automotive industry, awnings, and roofing.
  • Plates - Most commonly used for heavy-duty applications, including aerospace and military industries. It’s generally much harder to mill than sheet, due to the density and thickness.

Likely, you’ll mostly use sheets in your workshop since they’re the most common and easier to work with.

Advantages and Disadvantages of Cutting Aluminum with a CNC Router

When using a CNC for routing aluminum, there are both pros and cons to consider. As with any machinery, there are great advantages. However, under certain conditions, you can put yourself at a disadvantage as well. Let’s get into it.


The advantages of using your CNC as an aluminum router are manifold, and include:

  • Speed - When done correctly, using CNC routers for aluminum can make processing aluminum significantly faster. Compared to manual cutting techniques, and even some other types of machinery, CNCs are incredibly fast. This is partially because you can combine steps that you’d implement individually with other cutting devices.
  • Ease-of-use - Once you know the ins and outs of milling aluminum with a CNC router, routing aluminum becomes incredibly easy. It allows you to set and forget the machine, as long as you have a good lubrication system in place.
  • A smooth finish - As long as you stick to a few basic criteria, using a CNC router for aluminum creates a fantastic finish. Unlike many other ways of cutting aluminum, your machine will produce a perfect finish that requires no additional smoothing.
  • Requiring less manpower - Since CNC machines are easy to use, and work quickly, you’ll require fewer people to accomplish the same tasks.
  • Versatility - By simply changing the bits on the machine, and/or the orders being sent to the machine, you can have your CNC accomplish various things. From cutting materials to size to rounding edges and creating tabs or slots, it can do it all.


As we’re sure you expected, cutting aluminum with a CNC router isn’t an entirely problem-free task. Some of the disadvantages of aluminum that make it difficult to route include:

  • A low melting point - While this metal’s melting point is one of the things that makes its alloys useful, it can be a con. Since aluminum melts relatively easily, the material that the router removes can begin to melt and glob together. This process is known as welding.
  • Extreme stickiness - Aluminum tends to stick to anything it comes into contact with. This is especially true when the metal is in the form of chips or shavings.
  • Aluminum alloys have often found use in toys that require metal filings to move together. In the context of your CNC, this can lead to clumping together, which increases the chances of chips welding to your bits and each other.
  • Prone to chipping - Aluminum alloys are extremely prone to chipping. This means that you have to be cautious when cutting this metal with a CNC. If you try to remove too much material at once or to cut too quickly, you can easily chip the edges.
  • Requires more expensive bits - Since aluminum is a metal (albeit a relatively soft one), it requires harder bits than most materials. Unlike wood, foam, plastic, or other soft materials, you’d want a high-strength steel (HSS) tool at the very least. We’d recommend a carbide-coated or solid carbide bit for most applications.
  • Takes a heavy toll on cutting tools - Not only will you need more expensive bits to cut aluminum, but this material takes a heavy toll. Especially at the beginning, you’re likely to burn through quite a lot of bits and cutting tools. This is mainly due to aluminum’s low melting point and stickiness. However, since the CNC needs to make so many passes, you’ll also find that the lower cutting edge of your tools blunts quite quickly.
  • Low speed compared to other materials - While this may sound directly contrary to the advantage of speed, it’s not. Cutting aluminum with a CNC is significantly faster than using most other tools. However, if you’re used to working with wood and soft materials, you may find the slower process required by aluminum to be tedious.

While all of these things are true, many of aluminum’s disadvantages can be mitigated with some experience. In the next section, we’ll share some handy hints and tips that will help you make the most of your aluminum routing experience.

Tips for Cutting Aluminum Effectively

When you’re using CNC routers for aluminum, there are a few things you ought to know. Let’s take a closer look at some essential tips that can help you cut aluminum well.

By following our sage advice, you’ll probably save yourself a pretty penny by cutting down on tool wear, material wastage, and other unnecessary expenses.

1- Choose the Right Tools and Bits

Although aluminum is a relatively soft metal, it’s still a fair bit harder than most woods and plastics. Taking this into account, you need to choose the right tools and bits to deal with its unique challenges.

Some of the things that matter most when it comes to choosing bits are:

  • What the bit is made of - Bits for cutting aluminum generally consist of carbide or high-strength steel (HSS). We recommend carbide because it’s generally stronger and more durable than HSS, especially when working with thicker sheets or plates.
  • The shape of the bit - Different types of CNC bits have different shapes which accomplish different things.

When using your CNC as an aluminum router, you need exceptional chip clearance. Aluminum tends to make plenty of chips as you cut it. This can lead to a build-up of aluminum shavings, which leads to friction and warped bits.

The best types of bits for this kind of project include compression bits, downcut bits, and V-bits. Each of these types is specially formulated to help remove debris from the workpiece as the machine cuts.

  • The number of flutes - You’ll want to use a bit with at least two or three flutes. Again, the intense chipping process when cutting aluminum means that you want as much debris removal as possible. More flutes result in a higher portion of the aluminum shavings being swept up by the bit, leading to cleaner cuts.

So, considering all these requirements, which kind of bit do we recommend when using a CNC router for aluminum? Our top choice would have to be a carbide endmill sporting multiple flutes. This type of bit is well-equipped to handle all the unique challenges that come with aluminum.

If you find carbide bits are a bit expensive, you may want to opt for carbide-coated bits instead. They have much of the durability of carbide, but with a much lower price tag.

As a last resort, consider trying HSS. Steel is considerably cheaper, but doesn’t have the same lifespan. However, when you’re learning and burning through a ton of tools, cheaper is often better. Once you’ve familiarized yourself with the process, upgrade to the more expensive options.

2- Lubricate the Workpiece

Since aluminum sheets and plates are both smooth, and aluminum alloys are prone to rubbing and chipping, we strongly recommend lubricating the workpiece.

If you leave the router unattended for extended periods during the cutting process, lubrication is essential. If you neglect this one thing, you can easily come back to find your work materials, cutting tools, and machine damaged by friction and overheating.

Many machinists recommend setting up an oil misting system. In the grand scheme of things, these systems are easy to install and reasonably inexpensive. However, they’re only worth it if you regularly work with materials that need lubrication.

Alternatively, you can lubricate by hand and ensure that you don’t leave the machine alone for too long. One of the easiest lubricants to use this way is WD-40. Most workshops have some on hand anyway, so it’s easy enough to spray down the tool and workpiece now and then while routing.

You could also consider cutting wax, though this may not work well for all applications. Your best bet might be to try it out on a piece of scrap aluminum before applying it to your workpiece. You’d also need to apply fresh layers of wax to the inside of cuts and channels.

The potential is vast and varied, but most machinists recommend lubrication when working with aluminum on a CNC machine. Other machinists prefer using a blower to keep the workpiece free of chips and prevent welding.

If you do decide to use a compressor to blow the workpiece free of debris, instead of using a lubricant, we’d recommend sticking around to see how the process progresses. A tiny problem, like a loose air tube, or some aluminum chips that don’t blow away can lead to your bit welding to the machine.

Another oft-recommended option when working with aluminum is to use a type of coolant, rather than a lubricant. Instead of keeping the material lubricated, it deals with the overheating aspect of the process. However, using coolant can lead to the aluminum chips globbing together, which doesn’t solve the problem.

3- Pay Careful Attention to Speeds and Feeds

If you’ve been using CNC routers for a while, then you know that every CNC machine has a “sweet spot.” The sweet spot is the place where feed rate, speed, and optimal tool operation intersection.

The sweet spot varies depending on the material in use because each type of material reacts differently to specific feed rates and RPMs. For metals like aluminum, the sweet spot is considerably smaller than it would be for wood, foam, or plastic.

Why? Well, they have different textures and melting points. If your tool moves too fast or tries to feed too quickly, the material can chip or even melt. If it moves too slowly, you’ll likely experience rubbing and short tool lives.

Most manufacturers agree that the optimal spindle speed for a desktop-size CNC machine is around 10,000 RPM with a feed rate of around 40 IPM. Many larger CNC machines can go even slower, allowing you to compensate perfectly for the tool you’re currently using.

As you keep practicing and working on aluminum, you’ll develop an instinct for feeds and speeds that comes only with experience. You might want to consider keeping a notebook with different feeds and speeds you’ve tried, as well as the result.

4- Set Up Your Toolpaths Correctly

While it may not be the first thing you think about when using your CNC for aluminum product processing, the toolpaths play a significant role. Since you can’t remove too much material at once, you may want to use a faster feed rate.

However, if you use a faster feed rate and the wrong toolpath, the machine will unintentionally gather cast-off material in the cuts and channels. When setting your toolpath, ensure that you can clean one area before the machine makes another pass over it.

Additionally, you want to avoid drilling or boring actions. It’s better to make a light pass from a level position and create a basic channel to work with. If you try to plunge a cutting tool straight down into aluminum, it’s likely to get stuck, chip the material, or otherwise damage it.

If you have no other alternative, use a ramping motion to get your bit to the desired depth.

Finally, try to center your bit away from either side of the cut before you allow it to ascend after cutting. If you don’t do this, then the bit may leave a gouge on the side of the cut.

5- Use Tools and Bits with Smaller Diameters

Although many machinists like to use the biggest bits their machine can take, that’s not always beneficial when it comes to using CNC routers for aluminum.

The best thing you can do is to use smaller-diameter tools and make multiple passes if required. Why? Well, aluminum is a lot harder and thicker than most materials you’re likely to work with regularly. As a result, it can place a fair amount of pressure on the tool that you’re using to route with.

But, bigger bits can handle more pressure, right? While it may be counterintuitive, that’s not always the case. Because aluminum is quite sturdy, it provides a lot of “pushback” against the force of the router. Larger bits can generate more leverage than smaller tools, and therefore put more strain on your machine.

The best option is to use smaller diameter tools that fit in a small collet. This allows the machine to counterbalance more effectively, and also counteract much of the wobbling caused by the aluminum.

Smaller-diameter tools also handle higher speeds much better than large-diameter tools. If your machine isn’t capable of the low RPM (<30,000) that you’d need to make clean cuts with a large tool, it’s best to stick to smaller diameters.

6- Keep the Workpiece Clean

We’ve said it once or twice, and we’ll say it again. Aluminum makes a lot of chips. If you want your project to cut well, and have clean edges, you have to make sure that no chips stay in the channels and cuts.

Even if your machine is set up with a vacuum and brush attachment, it will be worth your while to check for renegade chips now and then. Even if that means pausing the machine and using a paintbrush, vacuum, or air blower to keep your cuts clean.

Maintaining a neat environment will help protect your machine against the rigors of cutting aluminum. You’re also less likely to encounter rubbing and gliding.

Another problem that you may encounter with aluminum is that it’s incredibly sticky. It’s not that it’s highly magnetic, or anything along those lines, it just tends to stick to itself and everything around it. If you’re not careful to keep your machine well-lubricated and clean, then the aluminum shavings can easily weld to the bit or the workpiece.

7- Try To Keep Your Cutting Depths Low

We’ll probably say this more than once, but it’s vital to a flawless process. When milling aluminum with a router, ensure that you keep your cutting depths low.

It’s better to make many passes than to try and remove too much at once. Not only will it help to prevent a buildup of cast-off material, but it will help prevent chipping.

If you try to remove too much material at once, it’s likely that the aluminum will chip or that flakes will break off.

Fortunately, if you use short bits and a low cutting depth, you can typically set your feeds and speeds somewhat higher. The main thing to bear in mind is that you’ll have to check regularly to ensure the cutting area stays clear of debris.

8- Compensate for Your Machine’s Rigidity

Different sizes of CNC machines have different levels of rigidity and stability. When using CNC routers for aluminum, this rigidity can play a major role in how you set up the machine.

For instance, if you have a very small machine with quite a lot of flex you want to:

  • Don’t try to make deep cuts, use multiple passes instead. You can probably go as low as one-hundredth of an inch if your machine is truly tiny. Larger machines may be able to handle around one twenty-fifth of an inch. Again, you’ll have to learn what works through some trial and error.
  • Stay away from cutting tools and bits that are too long. Shorter bits will reduce the amount of leverage that the workpiece applies to the machine. Stub-end bits are the best choice when you’re dealing with a small, flexible machine.

Taking these minor steps will prevent damage to your machine if the pressure happens to get too much for it to handle.

Larger machines with more rigidity probably won’t require the same precautions. However, we’d still recommend starting with a low cutting depth and working your way up to whichever depth your machine handles with ease. It’s better to take longer to finish the project than to try and finish quickly and break your machine.

We hope that this article about using a CNC router for aluminum processing has helped you come to grips with the advantages and potential challenges of going this route.

CNC machines can facilitate better aluminum processing, as long as you understand the potential pitfalls.

If you’re still looking for a CNC machine that’s worthy of your aluminum-routing ambitions, feel free to contact us. We’d love to help you set up a package that will suit your unique needs. From a lubrication mister to an engine with higher horsepower, and even vacuum attachments, we can help you create a fantastic system.

If you already have a CNC machine, but you’d like to learn more about CNC routing as a whole, check out our blog for excellent articles about CNC machines.

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