Your Cart is Empty
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:
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.
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.
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:
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’.
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:
Now that you understand the differences between the two types of manufacturing aluminum alloys, let’s look at some of the different alloys:
Of course, there are many other alloys as well. We’ve only looked at a few of the most commonly used alloys.
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:
Likely, you’ll mostly use sheets in your workshop since they’re the most common and easier to work with.
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:
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:
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.
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.
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:
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.
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.
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.
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.
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.
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.
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.
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.
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:
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.
Comments will be approved before showing up.
