Practical Tips for Smooth Aluminum CNC Machining

by David Woolf
Rapid Prototyping

Aluminum CNC machining is a process that is very popular among manufacturers and used for producing high-quality parts. However, just like other manufacturing processes, it has its challenges. 

Here is a set of practical tips that can minimize the challenges and lead to better products. 

Keep the temperature stable

It’s common knowledge that aluminum is sensitive to temperature variations. To avoid that, it is recommended to use software and hardware that can maintain the workload optimal so that the temperatures don’t get too high. 

Make sure that the aluminum chips are thoroughly cleaned

Aluminum chips tend to have some “stickiness” that makes them like welded to the tool. As a result, there is an excess wear and tear on the machine, as well as low quality work.

To avoid that, make sure you spread a lubricant through the machine. For example, a coolant mist can minimize the inclination of the chips to stick.

Furthermore, don’t put all your faith in dust collector systems. It is always better if you check the machine on your own and make sure that each chip is cleared out.

Fewer flutes means fewer problems

Again, this issue is also related to the aluminum chips and their “stickiness” issue. The thing is, too many flutes can worsen the chip problem as they will be packed too tightly. 

The recommendation here is to stick with up to three flutes when doing aluminum machining. This will result in increased space between the machine’s cutting edges which will allow for the larger chips to escape. 

Calculate optimum speeds and feeds

If the feed rates are too slow then the rubbing can wear and tear your tools. On the other hand, if the feed rates are too fast then the machine can be easily overburdened which will eventually lead to breakage.

In most cases when you are cutting aluminum, higher spindle speed is required. If the spindle speed is too high then it can easily push the outside CNC machine limits. 

“Playing it by ear” is one of those old-school methods that simply doesn’t work anymore as it gives too much room for mistakes. Plus, when people were doing it, the CNC machines were nothing like the ones today. So, it is a big no to this. 

So instead, it is for the best to stick with speeds and feeds calculator to find out the precise rates.

Use Carbide-coated Bits

The fact that cutting aluminum requires higher RPMs, it means that cobalt and high-speed steel shouldn’t be your first choice.

Instead, use carbide which is way more rigid and the most optimal material for aluminum cutting. 

Plus, the higher RPMs ask for smaller diameter bits. 

So its carbon-coated bits featuring smaller diameter for optimal aluminum cutting. 

Go steady, go slow

It is easy to be tempted into making deeper cuts. At first, you may think of it as a time-saving strategy. However, this can easily backfire by making it difficult for the chips to be cleared. 

The best strategy is to stick with shallow passes that ensure better control and the chips will be much easier to be removed.

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