Settings for aluminum

So I am playing with aluminum and doing very small details. I lowered all the settings that CC suggested by quite a bit (feeds, depth…) and it still sounds really bad and snapped a bit 3 seconds in. I finally manually set it to 20% feed in Carbide Motion and it seems to be OK. But curious what is the right way to set this and I will admit I only understand a few of these settings.

#112 - 0.063 end

DPP 0.002
Stepover 0.028 <-- Did not change
Spindle 9000 <–Did not change
Feed 5.000
Plunge 0.500

And I set the center just a hair above the work so the first pass would not be too harsh (like a business card thickness instead of paper).

These are small 1.5" discs and just trying a simple gear design as a pocket.

Your chipload is 0.0003 in/tooth. You are guaranteed rubbing at that point and not cutting proper chips. You need to increase your childhood to at least 0.00075 in/tooth (12.5 in/min) or better yet, to 0.001 (18 in/min). Aluminum is soft and gummy and you need to get a certain bite of the endmill into it or you will break endmills due to rubbing.


So how do I do that? Sorry still new to this.

Yep, no worries. Chipload or chip per tooth (CPT) is the radial depth of cut that the endmills engages every time a tooth hits the material. Think of it as how much material the endmill cuts off every time it rotates. So a chipload of 0.001" means that is you rotate at 9000 RPM and have 2 flutes, you cut 18 inches per minute (90000.0012).

For aluminum, it’s safe to start around 0.00075" CPT for smaller endmills (less than 1/8") and 0.001" CPT for larger endmills (1/8" or greater).

Does that make sense?


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