Tips for Efficient Aluminum Machining

CNC routers are frequently used with wood and acrylics, but they’re versatile enough to handle the demands of materials such as aluminum. The key to successful aluminum machining is adapting the process to accommodate its different characteristics.

Incorporate these tips to minimize the challenges and produce high-quality parts.

Calculate Proper Feeds and Speeds

As with most metals, the optimum feeds and speeds combination for aluminum is a more narrow range than that of wood or acrylics. Cutting aluminum requires a higher spindle speed that may push the outside limits of your CNC machine.

  • Feed rates that are too slow can cause rubbing that reduces the lifespan of tools.
  • Feed rates that are too fast can overburden the machine, resulting in breakage.

The old-school method of “playing it by ear” allows too much room for error. A feeds and speeds calculator will help you determine more precise rates.

Use Carbide-Coated Bits with Smaller Diameters

With the higher RPMs involved in cutting aluminum, high-speed steel and cobalt are not likely to be up to the task. Carbide is a more rigid material, making a preferable solution for bits.

Speedier machining rates also call for smaller diameter bits. The rigidity of carbide is another benefit here, as it will protect against potential tool deflection.

Maintain a Stable Temperature

Aluminum is more vulnerable to variations in temperature, causing waste as completed parts are out of tolerance. Use hardware and software that are capable of holding temperatures at an acceptable level.

Clear Chips Thoroughly

Aluminum chips have a certain “stickiness” factor that causes them to become essentially welded to the tool, resulting in poor quality work and excess wear and tear on machines.

  • Don’t rely exclusively on dust collector systems. Check the machine faithfully to ensure chips are cleared out.
  • Run a coolant mist or other lubricant through the machine to reduce the tendency of chips to stick.

Go Slow and Steady

There’s a temptation to save time by making deeper cuts, but this strategy can backfire by making it harder to clear chips. Stick with frequent shallow passes that allow greater control and better access for chip removal.

Reduce the Number of Flutes

Too many flutes can aggravate the chip problem by causing them to get packed in too tightly. Switch to a maximum of three flutes with aluminum machining. Increased space between the cutting edges makes it easier for larger chips to escape.

Our patented stacked aluminum machining process makes it possible to create perfectly finished parts without the cumbersome traditional stacking, drilling and riveting.

CNC Machines – The Effects of Acceleration/Deceleration

Let’s talk about acceleration! One of the simple joys of life. Whether it’s in Grandpa’s ’68 Nova or the catapult at the county fair, it’s fun stuff! At least it is for me; it makes my wife cry!

CNC Machining acceleration

For a CNC, and my wife, it’s, their worst nightmare.

CNC Machine acceleration and deceleration

Types of Acceleration

There are two types of acceleration we need to talk about. Linear acceleration and lateral acceleration. Linear acceleration is acceleration in a straight line. Like the intended direction of a top fuel dragster. Lateral acceleration is the acceleration around a corner or sometimes referred to as lateral force or in automotive terms, cornering forces.  Many times these forces will be measured in “G” forces. One “G” refers to the force of gravity. As an example, when you first step on to an elevator, assuming it’s not moving, you “weigh” 1G.  If the elevator goes up you feel yourself being pushed down slightly. Once the elevator reaches full speed everything is normal again.  On the flip side of that is if the elevator starts down you get that little butterfly feeling of reduced weight. But once the full speed is reached you weigh the same again.

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Methods of our Madness in Measurement: Procedures and Techniques in Calibration

axis freedom of movementIt All Starts with Understanding “CUZ!”

Sometimes I, The Master Blaster, The Exalted One (also known by other, less lofty titles), am asked, “Why the heck are you doing that that way”! I usually answer most emphatically, “CUZ!” The reply almost certainly is “CUZ WHY?” Then I respond, “CUZ I want to,” and away we go. After we have finally exhausted all our attempts to out “CUZ” each other, we get down to the whats and whys of what we do.
The question that is being asked here is how do we go about calibrating a machine and how do we decide on the settings to make the machine do what we need it to do. For example, if we are going to calibrate an X axis for linear positioning, how far apart do we need to set our measurement points?  The answer is of course, it depends. Hence, “CUZ.” It depends on what we need to produce. If we’re trimming plastic flashing off the rim of a thermoformed 5-gallon bucket, we don’t need to be as accurate as if we were making parts for the Mars Lander.

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Ups and Downs, In and Outs and Longs and Shorts of Encoders

CNC Machine Encoders

There are many kinds of encoders and feedback devices. There are resolvers, encoders, glass scales, interferometer scales, inductive scales, capacitive scales, pulse coders, rotary-linear encoders, and even mechanical-hydraulic encoders.  There are temperature specific scales and zero temperature scales. Each type of scale has its specific application and price. Also any type of scale can only perform at its best if installed, adjusted and maintained correctly.

As the senior technician of CMS’s metrology and calibration department I am sometimes called upon to figure out why “funny” things happen during positioning of an axis.  This last week was a prime example.

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